[Federal Register Volume 70, Number 128 (Wednesday, July 6, 2005)]
[Rules and Regulations]
[Pages 39104-39172]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-12526]
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Part III
Environmental Protection Agency
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40 CFR Part 51
Regional Haze Regulations and Guidelines for Best Available Retrofit
Technology (BART) Determinations; Final Rule
Federal Register / Vol. 70, No. 128 / Wednesday, July 6, 2005 / Rules
and Regulations
[[Page 39104]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 51
[FRL-7925-9]
RIN 2060-AJ31
Regional Haze Regulations and Guidelines for Best Available
Retrofit Technology (BART) Determinations
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: On July 1, 1999, EPA promulgated regulations to address
regional haze (64 FR 35714). These regulations were challenged, and on
May 24, 2002, the U.S. Court of Appeals for the District of Columbia
Circuit issued a ruling vacating the regional haze rule in part and
sustaining it in part. American Corn Growers Ass'n v. EPA, 291 F.3d 1
(D.C. Cir. 2002). Today's rule addresses the court's ruling in that
case.
In addition, prior to the court's decision, EPA had proposed
guidelines for implementation of the Best Available Retrofit Technology
(BART) requirements under the regional haze rule, (66 FR 38108, July
20, 2001). The proposed guidelines were intended to clarify the
requirements of the regional haze rule's BART provisions. We proposed
to add the guidelines and also proposed to add regulatory text
requiring that these guidelines be used for addressing BART
determinations under the regional haze rule. In addition, we proposed
one revision to guidelines issued in 1980 for facilities contributing
to ``reasonably attributable'' visibility impairment.
In the American Corn Growers case, the court vacated and remanded
the BART provisions of the regional haze rule. In response to the
court's ruling, on May 5, 2004 we proposed new BART provisions and
reproposed the BART guidelines. The American Corn Growers court also
remanded to the Agency its decision to extend the deadline for the
submittal of regional haze plans. Subsequently, Congress amended the
deadlines for regional haze plans (Consolidated Appropriations Act for
Fiscal Year 2004, Public Law 108-199, January 23, 2004). The May 5,
2004 proposed rule also contained an amendment to the regional haze
rule to conform to the new statutory deadlines.
We received numerous comments on both the July 20, 2001 proposal
and the May 5, 2004 reproposal. Today's final rule reflects our review
of the public comments.
DATES: The regulatory amendments announced herein take effect on
September 6, 2005.
ADDRESSES: Docket. All documents in the docket are listed in the
EDOCKET index at http://www.epa.gov/edocket. Although listed in the
index, some information is not publicly available, i.e., CBI or other
information whose disclosure is restricted by statute. Certain other
material, such as copyrighted material, is not placed on the Internet
and will be publicly available only in hard copy form. Publicly
available docket materials are available either electronically in
EDOCKET or in hard copy at the OAR Docket, EPA/DC, EPA West, Room B102,
1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744, and the telephone number for the OAR Docket is (202)
566-1742.
FOR FURTHER INFORMATION CONTACT: Kathy Kaufman at (919) 541-0102 or by
e-mail at [email protected] or Todd Hawes at 919-541-5591 or by e-
mail [email protected].
SUPPLEMENTARY INFORMATION:
Regulated Entities. This final rule will affect the following:
State and local permitting authorities and Indian Tribes containing
major stationary sources of pollution affecting visibility in federally
protected scenic areas.
This list is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This list gives examples of the types of entities EPA is now
aware could potentially be regulated by this action. Other types of
entities not listed could also be affected. To determine whether your
facility, company, business, organization, etc., is regulated by this
action, you should examine the applicability criteria in Part II of
this preamble. If you have any questions regarding the applicability of
this action to a particular entity, consult the people listed in the
preceding section.
Outline. The contents of today's preamble are listed in the
following outline.
I. Overview of Today's Proposed Actions
II. Background
A. Regional Haze Rule
B. Partial Remand of the Regional Haze Rule in American Corn
Growers
C. Changes in Response to American Corn Growers
D. Center for Energy and Economic Development v. EPA
E. Relationship Between BART and the Clean Air Interstate Rule
(CAIR)
F. Overview of the BART Process
III. Detailed Discussion of the BART Guidelines
A. Introduction
B. Scope of the Rule--Whether to Require States to Follow the
Guidelines for All BART Sources
C. How to Identify BART-Eligible Sources
D. How to Determine Which BART-Eligible Sources are Subject to
BART
E. The BART Determination Process
IV. Effect of This Rule on State Options for Using Alternative
Strategies In Lieu of Source-by-Source BART
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use.
I. National Technology Transfer Advancement Act
J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
I. Overview of Today's Actions
Today's rulemaking provides the following changes to the regional
haze regulations:
(1) Revised regulatory text in response to the American Corn
Growers court's remand, to require that the BART determination include
an analysis of the degree of visibility improvement resulting from the
use of control technology at each source subject to BART,
(2) Revised regulatory text in 40 CFR 51.308(b) and deletion of 40
CFR 51.308(c) Options for regional planning in response to
Congressional legislation amending the deadlines for submittal of
regional haze implementation plans. This provision had provided for an
alternative process for States to submit regional haze implementation
plans in attainment areas,
(3) BART guidelines, contained in a new Appendix Y to 40 CFR part
51,
(4) New and revised regulatory text, to be added to 40 CFR
51.308(e), regarding the use of Appendix Y in establishing BART
emission limits, and
(5) Revised regulatory language at 40 CFR 51.302 to clarify the
relationship between New Source Performance Standards (NSPS) and BART
for reasonably attributable visibility impairment.
How This Preamble Is Structured. Section II provides background on
the
[[Page 39105]]
Clean Air Act (CAA) BART requirements as codified in the regional haze
rule, on the D.C. Circuit Court decision which remanded parts of the
rule, and on the April 2004 reproposal responding to the remand.
Section III discusses specific issues in the BART guidelines in more
detail, including background on each issue, major comments we received
on the July 2001 proposal and May 2004 reproposal, and our responses to
those comments. Section IV provides a discussion of how this rulemaking
complies with the requirements of Statutory and Executive Order
Reviews.
II. Background
A. The Regional Haze Rule
In 1999, we published a final rule to address a type of visibility
impairment known as regional haze (64 FR 35714, July 1, 1999). The
regional haze rule requires States to submit implementation plans
(SIPs) to address regional haze visibility impairment in 156 Federally-
protected parks and wilderness areas. These 156 scenic areas are called
``mandatory Class I Federal areas'' in the Clean Air Act (CAA)\1\ but
are referred to simply as ``Class I areas'' in today's rulemaking. The
1999 rule was issued to fulfill a long-standing EPA commitment to
address regional haze under the authority and requirements of sections
169A and 169B of the CAA.
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\1\ See, e.g. CAA Section 169A(a)(1).
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As required by the CAA, we included in the final regional haze rule
a requirement for BART for certain large stationary sources that were
put in place between 1962 and 1977. We discussed these requirements in
detail in the preamble to the final rule (64 FR at 35737-35743). The
regulatory requirements for BART were codified at 40 CFR 51.308(e) and
in definitions that appear in 40 CFR 51.301.
The CAA, in sections 169A(b)(2)(A) and in 169A(g)(7), uses the term
``major stationary source'' to describe those sources that are the
focus of the BART requirement. To avoid confusion with other CAA
requirements which also use the term ``major stationary source'' to
refer to a somewhat different population of sources, the regional haze
rule uses the term ``BART-eligible source'' to describe these sources.
The BART-eligible sources are those sources which have the potential to
emit 250 tons or more of a visibility-impairing air pollutant, were put
in place between August 7, 1962 and August 7, 1977, and whose
operations fall within one or more of 26 specifically listed source
categories. Under the CAA, BART is required for any BART-eligible
source which a State determines ``emits any air pollutant which may
reasonably be anticipated to cause or contribute to any impairment of
visibility in any such area.'' Accordingly, for stationary sources
meeting these criteria, States must address the BART requirement when
they develop their regional haze SIPs.
Section 169A(g)(7) of the CAA requires that States must consider
the following factors in making BART determinations:
(1) The costs of compliance,
(2) The energy and nonair quality environmental impacts of
compliance,
(3) Any existing pollution control technology in use at the source,
(4) The remaining useful life of the source, and
(5) The degree of improvement in visibility which may reasonably be
anticipated to result from the use of such technology.
These statutory factors for BART were codified at 40 CFR
51.308(e)(1)(ii).
In the preamble to the regional haze rule, we committed to issuing
further guidelines to clarify the requirements of the BART provision.
The purpose of this rulemaking is to fulfill this commitment by
providing guidelines to assist States as they identify which of their
BART-eligible sources should undergo a BART analysis (i.e., which are
``sources subject to BART'') and select controls in light of the
statutory factors listed above (``the BART determination'').
B. Partial Remand of the Regional Haze Rule in American Corn Growers v.
EPA
In response to challenges to the regional haze rule by various
petitioners, the D.C. Circuit in American Corn Growers \2\ issued a
ruling striking down the regional haze rule in part and upholding it in
part. This section discusses the court's opinion in that case as
background for the discussion of specific changes to the regional haze
rule and the BART guidelines presented in the next two sections,
respectively.
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\2\ American Corn Growers et al. v. EPA, 291 F.3d 1 (2002).
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We explained in the preamble to the 1999 regional haze rule that
the BART requirements in section 169A(b)(2)(A) of the CAA demonstrate
Congress' intent to focus attention directly on the problem of
pollution from a specific set of existing sources (64 FR 35737). The
CAA requires that any of these existing sources ``which, as determined
by the State, emits any air pollutant which may reasonably be
anticipated to cause or contribute to any impairment of visibility [in
a Class I area],'' shall install the best available retrofit technology
for controlling emissions.\3\ In determining BART, the CAA requires the
State to consider several factors that are set forth in section
169(g)(2) of the CAA, including the degree of improvement in visibility
which may reasonably result from the use of such technology.
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\3\ CAA sections 169A(b)(2) and (g)(7).
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The regional haze rule addresses visibility impairment resulting
from emissions from a multitude of sources located across a wide
geographic area. Because the problem of regional haze is caused in
large part by the long-range transport of emissions from multiple
sources, and for certain technical and other reasons explained in that
rulemaking, we had adopted an approach that required States to look at
the contribution of all BART sources to the problem of regional haze in
determining both applicability and the appropriate level of control.
Specifically, we had concluded that if a source potentially subject to
BART is located within an upwind area from which pollutants may be
transported downwind to a Class I area, that source ``may reasonably be
anticipated to cause or contribute'' to visibility impairment in the
Class I area. Similarly, we had also concluded that in weighing the
factors set forth in the statute for determining BART, the States
should consider the collective impact of BART sources on visibility. In
particular, in considering the degree of visibility improvement that
could reasonably be anticipated to result from the use of such
technology, we stated that the State should consider the degree of
improvement in visibility that would result from the cumulative impact
of applying controls to all sources subject to BART. We had concluded
that the States should use this analysis to determine the appropriate
BART emission limitations for specific sources.\4\
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\4\ See 66 FR at 35737-35743 for a discussion of the rationale
for the BART requirements in the 1999 regional haze rule.
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In American Corn Growers v. EPA, industry petitioners challenged
EPA's interpretation of both these aspects of the BART determination
process and raised other challenges to the rule. The court in American
Corn Growers concluded that the BART provisions in the 1999 regional
haze rule were inconsistent with the provisions in the CAA ``giving the
states broad authority over BART determinations.'' 291 F.3d at 8.
Specifically, with respect to the test for determining whether a source
is subject to BART, the court held that the
[[Page 39106]]
method that EPA had prescribed for determining which eligible sources
are subject to BART illegally constrained the authority Congress had
conferred on the States. Id. The court did not decide whether the
general collective contribution approach to determining BART
applicability was necessarily inconsistent with the CAA. Id. at 9.
Rather, the court stated that ``[i]f the [regional haze rule] contained
some kind of a mechanism by which a state could exempt a BART-eligible
source on the basis of an individualized contribution determination,
then perhaps the plain meaning of the Act would not be violated. But
the [regional haze rule] contains no such mechanism.'' Id. at 12.
The court in American Corn Growers also found that our
interpretation of the CAA requiring the States to consider the degree
of improvement in visibility that would result from the cumulative
impact of applying controls in determining BART was inconsistent with
the language of the Act. 291 F.3d at 8. Based on its review of the
statute, the court concluded that the five statutory factors in section
169A(g)(2) ``were meant to be considered together by the states.'' Id.
at 6.
C. Changes in Response to American Corn Growers
Today's rule responds to the American Corn Growers court's decision
on the BART provisions by including changes to the regional haze rule
at 40 CFR 51.308, and by finalizing changes to the BART guidelines.
This section outlines the changes to the regional haze rule due to the
court's remand. It also explains the minor change we are making to the
section of the regulation governing the use of the 1980 BART guidelines
when conducting BART analyses for certain power plants for reasonably
attributable (i.e., localized) visibility impairment.
1. Determination of Which Sources Are Subject to BART
Today's action addresses the American Corn Growers court's vacature
of the requirement in the regional haze rule requiring States to assess
visibility impacts on a cumulative basis in determining which sources
are subject to BART. Because this requirement was found only in the
preamble to the 1999 regional haze rule (see 291 F.3d at 6, citing 64
FR 35741), no changes to the regulations are required. Instead, this
issue is addressed in the BART guidelines, which provide States with
appropriate techniques and methods for determining which BART-eligible
sources ``may reasonably be anticipated to cause or contribute to any
impairment of visibility in any mandatory Class I Federal area.'' These
processes, to address the holding of American Corn Growers by
eliminating the previous constraint on State discretion, are explained
in further detail in sections II.D. and III below.
2. Consideration of Anticipated Visibility Improvements in BART
Determinations
Pursuant to the remand in American Corn Growers, we are amending
the regional haze rule to require the States to consider the degree of
visibility improvement resulting from a source's installation and
operation of retrofit technology, along with the other statutory
factors set out in CAA section 169A(g)(2), when making a BART
determination. This has been accomplished by listing the visibility
improvement factor with the other statutory BART determination factors
in 40 CFR 51.308(e)(1)(A), so that States will be required to consider
all five factors, including visibility impacts, on an individual source
basis when making each individual source BART determination.
D. Center for Energy and Economic Development v. EPA
After the May 2004 reproposal of the BART guidelines, the D.C.
Circuit decided another case where BART provisions were at issue,
Center for Energy and Economic Development v. EPA, 398 F.3d 653, 2005
(``CEED''). In this case, the court granted a petition challenging
provisions of the regional haze rule governing the optional emissions
trading program for certain western States and Tribes (the ``WRAP Annex
Rule'').
The court in CEED affirmed our interpretation of CAA section
169A(b)(2) as allowing for non-BART alternatives where those
alternatives are demonstrated to make greater progress than BART.
(CEED, slip. op. at 13). The court, however, took issue with provisions
of the regional haze rule governing the methodology of that
demonstration. Specifically, 40 CFR 51.308(e)(2) requires that
visibility improvements under source-specific BART--the benchmark for
comparison to the alternative program--be estimated based on the
application of BART controls to all sources subject to BART. (This
section was incorporated into the WRAP Annex rule by reference at 40
CFR 51.309(f)). The court held that we could not require this type of
group BART approach--vacated in American Corn Growers in a source-
specific BART context--even in a program in which State participation
was wholly optional.
The BART guidelines as proposed in May 2004 contained a section
offering guidance to States choosing to address their BART-eligible
sources under the alternative strategy provided for in 40 CFR
51.308(e)(2). This guidance included criteria for demonstrating that
the alternative program achieves greater progress towards eliminating
visibility impairment than would BART.
In light of the D.C. Circuit's decision in CEED, we have not
included the portion of the proposed BART guidelines addressing
alternative programs in today's rulemaking. We remain committed to
providing States with the flexibility to address BART through
alternative means, and we note again that our authority to do so was
upheld in CEED. Therefore, we intend to revise the provisions of the
regional haze rule governing such alternatives and provide any
additional guidance needed in a subsequent rulemaking conducted as
expeditiously as practicable.
E. Relationship Between BART and the Clean Air Interstate Rule (CAIR)
On March 10, 2005, EPA issued the Clean Air Interstate Rule (CAIR),
requiring reductions in emissions of sulfur dioxide (SO2)
and nitrogen oxides (NOX) in 28 eastern States and the
District of Columbia. When fully implemented, CAIR will reduce
SO2 emissions in these states by over 70 percent and
NOX emissions by over 60 percent from 2003 levels. The CAIR
imposes specified emissions reduction requirements on each affected
State, and establishes an EPA-administered cap and trade program for
EGUs in which States may participate as a means to meet these
requirements. The relationship between BART and the Clean Air
Interstate Rule (CAIR) is discussed in section IV. below.
F. Overview of the BART Process
The process of establishing BART emission limitations can be
logically broken down into three steps: First, States identify those
sources which meet the definition of ``BART-eligible source'' set forth
in 40 CFR 51.301. Second, States determine whether such sources
``emit[] any air pollutant which may reasonably be anticipated to cause
or contribute to any impairment of visibility [in a Class I area.]'' A
source which fits this description is ``subject to BART.'' Third, for
each source subject to BART, States then identify the appropriate type
and the level of control for reducing emissions.
[[Page 39107]]
Identifying BART-eligible sources. The CAA defines BART-eligible
sources as those sources which fall within one of 26 specific source
categories, were built during the 15-year window of time from 1962 to
1977, and have potential emissions greater than 250 tons per year. The
remand did not address the step of identifying BART-eligible sources,
which is conceptually the simplest of the three steps.
Sources reasonably anticipated to cause or contribute to visibility
impairment (sources subject to BART). As we noted in the preamble to
the 1999 regional haze rule, defining the individual contributions of
specific sources of the problem of regional haze can be time-consuming
and expensive. Moreover, Congress established a very low threshold in
the CAA for determining whether a source is subject to BART. We are
accordingly finalizing several approaches for States for making the
determination of whether a source ``emits any pollutants which may
reasonably be anticipated to cause or contribute to any visibility
impairment.'' Certain of these approaches would allow States to avoid
undertaking unnecessary and costly studies of an individual source's
contribution to haze by allowing States to adopt more streamlined
processes for determining whether, or which, BART-eligible sources are
subject to BART.
In 1999, we adopted an applicability test that looked to the
collective contribution of emissions from an area. In particular, we
stated that if ``a State should find that a BART-eligible source is
`reasonably anticipated to cause or contribute' to regional haze if it
can be shown that the source emits pollutants within a geographic area
from which pollutants can be emitted and transported downwind to a
Class I area.'' \5\ States certainly have the discretion to consider
that all BART-eligible sources within the State are ``reasonably
anticipated to cause or contribute'' to some degree of visibility
impairment in a Class I area.
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\5\ 64 FR 335740, July 1, 1999. The regional haze rule discusses
at length why we believe that States should draw this conclusion. 64
FR at 35739-35740.
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This is consistent with the American Corn Growers court's decision.
As previously noted, the court's concern with our original approach
governing BART applicability determinations was that it would have
``tie[d] the states' hands and force[d] them to require BART controls
at sources without any empirical evidence of the particular source's
contribution to visibility impairment.'' 291 F.3d at 8. By the same
rationale, we believe it would be an impermissible constraint of State
authority for the EPA to force States to conduct individualized
analyses in order to determine that a BART-eligible source ``emits any
air pollutant which may reasonably be anticipated to cause or
contribute to any impairment of visibility in any [Class I] area.'' \6\
American Corn Growers did not decide whether consideration of
visibility impact on a cumulative basis would be invalid in all
circumstances. 291 F.3d at 9. Given the court's emphasis on the
importance of the role of the States in making BART determinations, we
believe that a State's decision to use a cumulative analysis at the
eligibility stage is consistent with the CAA and the findings of the
D.C. Circuit.
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\6\ CAA section 169A(b)(2)(A).
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We believe a State may conclude that all BART-eligible sources
within the State are subject to BART.\7\ Any potential for inequity
towards sources could be addressed at the BART determination stage,
which contains an individualized consideration of a source's
contribution in establishing BART emission limits.
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\7\ See 64 FR at 35714, 35721; see also Supporting Information
for Proposed Applicability of Regional Haze Regulations, Memorandum
by Rich Damberg to Docket A-95-38, U.S. Environmental Protection
Agency, Office of Air Quality Planning and Standards, July 29, 1997.
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States also have the option of performing an analysis to show that
the full group of BART-eligible sources in a State cumulatively may not
be reasonably anticipated to cause or contribute to any visibility
impairment in Class I areas. We anticipate that in most, if not all
States, the BART-eligible sources are likely to cause or contribute to
some visibility impairment in Class I areas. However, it is possible
that using a cumulative approach, a State could show that its BART
sources do not pose a problem.
Finally, States may consider the individualized contribution of a
BART-eligible source to determine whether a specific source is subject
to BART. Specifically, States may choose to undertake an analysis of
each BART-eligible source in the State in considering whether each such
source meets the test set forth in the CAA of ``emit[ting] any air
pollutant which may reasonably be anticipated to cause or contribute to
any impairment of visibility in any [Class I] area.'' Alternatively,
States may choose to presume that all BART-eligible sources within the
State meet this applicability test, but provide sources with the
ability to demonstrate on a case by case basis that this is not the
case. Either approach appears consistent with the D.C. Circuit's
statement that a collective contribution approach may be appropriate so
long as the States are allowed to exempt sources on the basis of an
individualized contribution determination. 291 F.3d at 8.
Today's guidelines include different options States can use to
assess whether source should be subject to BART. States need to
determine whether to make BART determinations for all of their BART-
eligible sources, or to consider exempting some of them from BART
because they may not reasonably be anticipated to cause or contribute
to any visibility impairment in a Class I area. For assessing the
impact of BART-eligible sources on nearby Class I areas, we are
including a process whereby the States would use an air quality model
able to estimate a single source's contribution to visibility
impairment and a different process whereby States could exempt groups
of sources with common characteristics based on representative model
plant analyses. Finally, States may use cumulative modeling to show
that no sources in a State are subject to BART.
The BART determination. The State must determine the appropriate
level of BART control for each source subject to BART. Section
169A(g)(7) of the CAA requires States to consider the following factors
in making BART determinations: (1) The costs of compliance, (2) the
energy and nonair quality environmental impacts of compliance, (3) any
existing pollution control technology in use at the source, (4) the
remaining useful life of the source, and (5) the degree of improvement
in visibility which may reasonably be anticipated to result from the
use of such technology. The remand did not address the first four steps
of the BART determination. The remand did address the final step,
mandating that we must permit States to take into account the degree of
improvement in visibility that would result from imposition of BART on
each individual source when deciding on particular controls.
The first four factors are somewhat similar to the engineering
analysis in the original BART guidelines proposed in 2001 and
reproposed in 2004. The BART guidelines also contains a detailed
discussion of available and cost-effective controls for reducing
SO2 and NOX emissions from large coal-fired
electric generating units (EGUs).
For assessing the fifth factor, the degree of improvement in
visibility from various BART control options, the States may run
CALPUFF or another appropriate dispersion model to predict visibility
impacts. Scenarios would be
[[Page 39108]]
run for the pre-controlled and post-controlled emission rates for each
of the BART control options under review. The maximum 24-hour emission
rates would be modeled for a period of three or five years of
meteorological data. States have the flexibility to develop their own
methods to evaluate model results.
III. Detailed Discussion of the Final BART Guidelines
A. Introduction
In this section of the preamble, we discuss changes or
clarifications to the reproposed BART guidelines. Where relevant, we
also respond to comments received during the comment period on the 2001
proposal. For each provision of the guidelines that we are changing or
clarifying, we provide discussion of, as appropriate:
--Background information,
--How the provision was addressed in the May 2004 reproposal (and in
the 2001 proposal, if different from the reproposal),
--A summary of comments received on the provision, either from the May
2004 reproposal, from the July 2001 proposal, or from both, and
--The changes or clarifications that we are finalizing and the reasons
for these changes or clarifications.
B. Scope of the Rule--Whether To Require States To Follow the
Guidelines for All BART Sources
Background. Section 169A(b)(1) of the CAA requires EPA to issue
regulations to provide guidelines to States on the implementation of
the visibility program. In addition, the last sentence of section
169A(b) states:
In the case of a fossil-fuel fired generating powerplant having
a capacity in excess of 750 megawatts, the emission limitations
required under this paragraph shall be determined pursuant to
guidelines, promulgated by the Administrator under paragraph (1).
This statutory requirement clearly requires us to promulgate BART
guidelines that the States must follow in establishing BART emission
limitations for power plants with a total capacity exceeding the 750
megawatt cutoff. The statute is less clear regarding the import of the
guidelines for sources other than 750 megawatt power plants.
Proposed rules. Both the 2001 proposal and the 2004 reproposal
included a requirement for States to follow the procedures set out in
the guidelines in determining BART for sources in all of the 26 listed
BART categories. The 2001 proposal requested comment on whether the
regional haze rule should: (1) Require the use of the guidelines only
for 750 megawatt utilities, with the guidelines applying as guidance
for the remaining categories, or (2) require the use of the guidelines
for all of the affected source categories.
Comments. We received comments on this issue in both 2001 and 2004.
Comments varied widely on whether we can or should require the use of
the guidelines for all of the affected source categories.
Comments from State, local and tribal air quality agencies
generally supported our proposal to require the use of the guidelines
for all of the source categories. These comments cited a need for
national consistency in the application of the BART requirement across
the source categories, and from State to State. One State agency
commenter questioned our legal authority to require the use of the
guidelines for all source categories; and several State agency
commenters, while supporting the proposal, requested that we provide
clarification of the legal authority for requiring the States to use
the guidelines in establishing BART emission limitations for all
categories.
Comments from the utility industry, from various manufacturing
trade groups, and from individual companies were critical of the
proposal to require States to follow the guidelines generally. Many
commenters also argued that EPA lacked the authority to issue
guidelines for any industrial category other than 750 megawatt
powerplants, whether the use of such guidelines were mandatory or not.
Other commenters stated that the language in the CAA clearly restricts
the scope of mandatory guidelines to larger powerplants. The commenters
cited the legislative history of the 1977 Clean Air Act amendments in
support of this position, and frequently claimed that requiring the
guidelines for all 26 categories of sources would deprive States of
flexibility in implementing the program.
Comments from environmental organizations and the general public
supported the approach in the proposed rule and stated that EPA is
obligated to establish regional haze BART guidelines by rulemaking for
all 26 categories of stationary sources. Environmental organization
comments noted that while Congress expressed a particular concern for
750 MW powerplants, this added emphasis on one sector does not change
requirements in the Act for all BART-eligible sources. Accordingly,
these commenters believed that we should not construe a special
emphasis on powerplants as a restriction on our authority to require
use of the guidelines for all categories.
Final rule. The CAA and the relevant legislative history make clear
that EPA has the authority and obligation to publish mandatory
guidelines for powerplants exceeding 750 megawatts. As previously
noted, Congress in section 169A(b) of the CAA expressly provided that
emission limitations for powerplants larger than 750 megawatts ``shall
be determined pursuant to guidelines promulgated by the
Administrator.'' (Emphasis added). This unambiguous language leaves
little room to dispute that the guidelines EPA is required to
promulgate must be used by States when making BART determinations for
this class of sources.
Having carefully considered the comments and further reviewed the
CAA and the legislative history, we have concluded that it would not be
appropriate for EPA to require States to use the guidelines in making
BART determinations for other categories of sources. The better reading
of the Act indicates that Congress intended the guidelines to be
mandatory only with respect to 750 megawatt powerplants. Thus, while we
acknowledge the State agency comments and the policy reasons support
consistency across States, we are not requiring States to use the BART
guideline for these other categories. In response to State concerns
about equitable application of the BART requirement to source owners
with similar sources in different States, we do encourage States to
follow the guidelines for all source categories but are not requiring
States to do so. States should view the guidelines as helpful guidance
for these other categories.
We disagree with comments that the CAA and the legislative history
prohibit us from issuing guidance for other source categories. As the
guidelines make clear, States are not required to follow the approach
in the guidelines for sources other than 750 megawatt powerplants. As
such, although we believe that the guidelines provide useful advice in
implementing the BART provisions of the regional haze rule, we do not
believe that they hamper State discretion in making BART
determinations.
C. How To Identify BART-Eligible Sources
Section II of the BART guidelines contains a step-by-step process
for identifying stiationary sources that are ``BART-eligible'' under
the definitions in the regional haze rule. The four basic steps are:
Step 1: Identify the emission units in the BART categories.
Step 2: Identify the start-up dates of those emission units.
[[Page 39109]]
Step 3: Compare the potential emissions from units identified in
Steps 1 and 2 to the 250 ton/year cutoff.
Step 4: Identify the emission units and pollutants that constitute
the BART-eligible source.
In this section of the preamble, we discuss some of the comments we
received on the steps in this process, and any changes we are making in
light of those comments.
Step 1: Identify the Emission Units in the BART Categories
The BART guidelines list the 26 source categories that the CAA uses
to describe the types of stationary sources that are BART-eligible.
Both proposals clarified the descriptions of particular source
categories.
Comments. The final rule addresses comments on the following source
categories. Some comments discussed below were submitted in response to
the 2001 propoosal and were not addressed in the reproposal; other
comments were submitted in response to the reproposal in 2004.
(1) ``Charcoal production facilities.'' We received comments in
2001 from two industry trade groups requesting that the final
guidelines explicitly exclude ``low-emission'' charcoal production
facilities from BART. These comments cited a 1975 study considered by
Congress in development of the BART category list in the 1977 CAA
amendments. This 1975 study noted that some charcoal production
facilities have much higher emissions factors (i.e., 352 pounds of PM
per ton of charcoal produced versus 20 to 25 pounds of PM per ton of
charcoal produced). Accordingly, the comments asserted that the intent
of Congress in the 1977 CAA amendments was to provide incentives for
higher-emitting facilities to reduce their emissions, rather than to
make the entire category BART-eligible.
(2) ``Chemical process plants.'' In 2001 a trade group representing
the pharmaceutical industry requested that we determine in the
guidelines that the term ``chemical process plants'' does not include
pharmaceutical plants.
(3) ``Primary aluminum ore reduction.'' Comments from the aluminum
industry in 2001 noted that not all emissions units at these facilities
are necessarily involved in ``primary ore reduction.'' Thus, the
comments recommended that we clarify that contiguous sources that are
not related to primary aluminum ore reduction, such as fabricating
facilities and ingot operations, are not BART-eligible. Further, the
comments recommended that we use definitions in the NSPS for primary
aluminum plants to describe the BART-eligible emissions units.
(4) ``Fossil-fuel fired steam electric plants of more than 250
million Btu/hour heat input.'' The 2004 reproposal contained the
clarification, requested by commenters, that this source category
refers only to those fossil-fuel fired steam electric plants that
generate electricity for sale. One commenter objected to this
clarification on the basis that emissions from co-generators would be
excluded; many other commenters supported the clarification. Another
commenter requested that we also clarify that this category includes
only those steam electric plants that burn greater than 50 percent
fossil fuel, in order to be consistent with the definition of fossil-
fuel boilers proposed in the guidelines. Other commenters requested
that we clarify whether the definition includes units which are located
at a steam electric plant, but which themselves are not in any of the
26 BART source categories, such as simple cycle turbines, emergency
diesel engines, and reciprocating internal combustion engines (RICE).
Several commenters opined that the category should exclude combined
cycle units with heat recovery steam generators that lack auxiliary
firing, arguing that these units should count as simple cycle turbines.
These commenters pointed to other EPA regulatory programs that treat
combined cycle units with supplemental firing differently from combined
cycle units without supplemental firing. They argued that we should
only consider a combined cycle unit to be a ``steam electric plant'' if
it has supplemental firing.
(5) ``Fossil-fuel boilers of more than 250 million Btu/hour heat
input.'' The 2004 reproposal clarified that this category should be
read as including only those boilers individually greater than 250
million Btu/hour heat input. We received many comments on this
interpretation, both in favor and opposed. Those favoring this
interpretation (generally industry commenters) cited the implementation
burden that including smaller boilers would pose, the high cost-
effectiveness of controlling smaller boilers, and the relatively
smaller impact on regional haze that smaller boilers would pose. They
also noted that this interpretation is most consistent with definitions
in the NOX SIP call and new source performance standards
(NSPS).
Commenters opposing this interpretation (environmental groups, one
state, and one regional planning organization) noted that regarding all
boilers, irrespective of size, as BART-eligible so long as the
aggregate heat input exceeds 250 million Btu/hour is more consistent
with the definition of stationary source under the Prevention of
Significant Deterioration (PSD) program. These commenters noted that
under the CAA, BART and PSD are complementary programs aimed at
regulating the same source categories; either one or the other applies
depending upon when the source was constructed.
The 2004 reproposal also clarified that if a boiler smaller than
250 million Btu/hour heat input is an integral part of an industrial
process in a BART source category other than electric utilities, then
the boiler should be considered part of the BART-eligible source in
that category. Under these circumstances, the boiler, as part of the
BART-eligible source, should be considered for emission control. Some
commenters opposed this interpretation, asserting that it would result
in an ``arbitrary and capricious'' inconsistency, in that some smaller
boilers would be BART-eligible, and others would not. These commenters
also noted that these boilers could be included in regional haze SIPs
as necessary for making ``reasonable progress'' toward CAA visibility
goals, even if they are not considered to be BART-eligible.
Final rule. After considering the comments, we have made the
following determinations on the definitions of the following source
categories:
(1) ``Charcoal production facilities.'' We believe that in using
the term ``charcoal production facilities'' Congress intended to
encompass all types of charcoal production facilities. We do not agree
with comments that any inferences can necessarily be made regarding the
presence of different PM emission factors for different types of
charcoal production facilities in the 1975 report. For example, if
Congress only intended to regulate a subset of the charcoal production
industry, then we believe Congress could have easily indicated this in
the source category title, as was done for ``kraft pulp mills'' and for
``coal cleaning plants (thermal dryers).'' We also note that it is more
likely that plants in the charcoal production industry with lower
emission factors have emissions that are less than the 250 tons per
year cutoff for BART eligibility.
(2) ``Chemical process plants.'' We believe that there is a clear
precedent to include pharmaceutical manufacturing operations as
``chemical process plants.'' In the standard industrial classification
(SIC) system, pharmaceutical operations are generally
[[Page 39110]]
in SIC codes 2833 and 2834, which are a subset of 2-digit category 28
``Chemical and Allied products.'' Similarly, in the new North American
Industrial Classification Codes (NAICS), pharmaceutical manufacturing
is codes 32541 and 32542, which is a subset of the ``chemical
manufacturing subsector'' which is code 325. Accordingly, in the PSD
program, pharmaceutical plants have been treated as ``chemical process
plants.'' The commenter is correct in noting that EPA has consistently
distinguished between chemical manufacturing and pharmaceutical
manufacturing. Examples where different standards or guidelines are
established included control technique guideline (CTG) documents, NSPS
standards under section 111 of the CAA, and, most recently, maximum
achievable control technology (MACT) standards under section 112 of the
CAA. We do not agree that these differentiations for emissions
standards necessarily require differentiation for purposes of
determining BART eligibility. Therefore we believe pharmaceuticals
should not be excluded from BART. However, we expect that because of
the MACT standards, there is a very low probability that BART
determinations will lead to further control requirements from chemical
production processes at pharmaceutical plants.
(3) ``Primary aluminum ore reduction.'' We agree with commenters
that BART-eligible units in this source category should be defined
consistently with the NSPS definition for primary aluminum ore
reduction. Therefore we have added a clarification to that effect in
the final BART guidelines. We note that this definition is also
consistent with the definition at 40 CFR 63.840, which establishes
applicability for this source category for the MACT program.
(4) ``Fossil-fuel fired steam electric plants of more than 250
million Btu/hour heat input.'' We have retained the clarification that
this source category refers only to those fossil-fuel fired steam
electric plants that generate electricity for sale. We believe that
this clarification helps to distinguish those plants that are electric
utilities from plants in other industrial categories. We also believe
that while large co-generators would be excluded from the fossil-fuel
fired steam electric plant source category, most large co-generators
will be BART-eligible under the fossil-fuel fired boilers source
category.
We do not believe it makes sense for this category to include only
those steam electric plants that burn greater than 50 percent fossil
fuel. We do not believe that a boiler should be excluded from BART
review simply because it is located at a plant which burns less than 50
percent fossil fuel. Emissions from any such boiler could be a
significant contributor to regional haze, and as such, we believe that
each fossil-fuel fired boiler merits a BART review.
We do wish to clarify that units which are located at a steam
electric plant, but which themselves are not in any of the 26 BART
source categories, should not be considered to be BART-eligible units.
We believe that Congress intended that BART review be focused on units
in the source categories it delineated. This interepretation is most
consistent with the definition of BART-eligible source as we have
explained it elsewhere in this preamble in reference to whether entire
plants are included if only some units at the plant meet the statutory
criteria.
Finally, we believe that all combined cycle units are included in
the definition of fossil fuel fired steam electric plant, regardless of
whether the combined cycle unit's heat recovery steam generator lacks
auxilliary firing. Commenters are correct that some EPA programs have
treated combined cycle units with supplemental firing differently from
combined cycle units without supplemental firing. However, while some
EPA programs do not consider a unit to be a combined cycle unit unless
it contains supplemental firing, the definition at issue here is the
definition of fossil-fuel fired steam electric plant, not fossil-fuel
fired unit. The CAA defines both ``stationary source'' (for visibility
purposes) and ``major emitting facility'' (for PSD purposes) to include
``fossil fuel fired steam electric plants.'' In previous guidance for
PSD, we have explained that combined cycle gas turbines do fall within
the category of ``fossil-fuel fired steam electric plants.'' \8\
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\8\ See http://www.epa.gov/Region7/programs/artrd/air/nsr/nsrmemos/turbines.pdf.
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(5) ``Fossil-fuel boilers of more than 250 million Btu/hour heat
input.'' We have decided to retain the interpretation that this
category should be read as including only those boilers individually
greater than 250 million Btu/hour heat input. We agree with commenters
who noted that including smaller boilers would pose considerable
implementation burden. As noted in the 2004 reproposal notice, we do
not believe that this interpretation is likely to have a substantial
impact. Because smaller boilers are generally less cost-effective to
control, we believe that BART review would be unlikely to result in a
significant amount of control on these boilers.
We are also retaining the clarification that if a boiler smaller
than 250 million Btu/hour heat input is an integral part of an
industrial process in a BART source category other than electric
utilities, then the boiler should be considered part of the BART-
eligible source in that category. (By ``integral to the process'', we
mean that the process uses any by-product of the boiler, or vice-versa.
We have added this clarification to the definition in the BART
guidelines.) We believe that if a State is already considering a BART-
eligible industrial process for control, and a boiler is integrated
into that process, it makes common sense not to prematurely rule out
control options any of the emissions from that process as a whole.
(Note that a boiler which is not integral, but is simply attached to a
plant, should not be included.) For example, Kraft pulp mills may have
boilers that are not serving the energy infrastructure of the plant but
typically are serving a process directly by using the waste liquor from
the process. Including such a boiler in consideration of control
options for the process adds minimal additional burden while leaving
maximum discretion to the State in determining BART for the process as
a whole.
We are also clarifying today that we have determined that this
category should include all individual boilers of greater than 250
million Btu/hour heat input burning any amount of fossil fuel, as
opposed to only those boilers that burn greater than 50 percent fossil
fuel. We believe that it is quite possible that boilers of this size
could contribute to regional haze in a Class I area even if they burn
less than 50 percent fossil fuel. Therefore we believe that each fossil
fuel-fired boiler merits a BART review.
Step 2: Identify the Start-up Dates of Those Emission Units
Background. BART applies only to a major stationary source which
``was in existence on August 7, 1977 but which has not been in
operation for more than fifteen years as of such date.'' The visibility
regulations define ``in existence'' and ``in operation'' in 40 CFR
51.301. Under these regulations, promulgated in 1980, ``in existence''
means
that the owner or operator has obtained all necessary
preconstruction approvals or permits * * * and either has (1) begun,
or caused to begin, a continuous program of physical on-site
construction of the facility or (2) entered into binding agreements
or contractual obligations.
[[Page 39111]]
The term ``in operation'' means engaged in activity related to the
primary design function of the source.
Step 2 also addresses the treatment of ``reconstructions'' and
``modifications.'' Under the definition of BART-eligible facility,
sources which were in operation before 1962 but reconstructed during
the 1962 to 1977 time period are treated as new sources as of the time
of reconstruction.\9\ The same policies and procedures for identifying
reconstructed ``affected facilities'' under the NSPS are used to
determine whether a source has been reconstructed for purposes of the
BART requirements. ``Modifications'' under the CAA refers to physical
change or change in the method of operation at a source which has led
to an increase in emissions. In the proposed BART guidelines, we stated
that the best interpretation of the visibility provisions is that a
modification to a source does not change an emission's unit
construction date for purposes of BART applicability. We requested
comment on an alternative interpretation that we believed would be more
difficult to implement. Under this approach, sources built before 1962
but modified during the 1962 to 1977 time frame would be considered
``new'' at the time of modification.
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\9\ However, sources reconstructed after 1977, which
reconstruction had gone through NSR/PSD permitting, are not BART-
eligible.
---------------------------------------------------------------------------
Comments. We received comments in 2001 and 2004 on the discussion
in the guideline of the term ``in existence.'' These comments were
critical of our statement in the guidelines that sources which had
``commenced construction,'' that is, those which had entered into
binding contracts, would be considered to be in existence, even if
actual operations did not begin until after the August 7, 1977 cutoff
date. These commenters asserted that Congress did not intend to treat a
source as ``existing'' in 1977 if it was not yet built.
Other commenters interpreted the proposed guidelines as expanding
the definition of BART-eligible sources by requiring States to find
that all emission units at a facility are BART-eligible if one part of
the facility was built within the 1962-1977 time period. Other comments
did not suggest that we had already expanded the definition in the
proposed guidelines, but did suggest that we should expand the
definition in that way in the final guidelines. Some commenters noted
that there was a degree of confusion in the regulated community on
whether the proposed guidelines were requiring BART for all units at a
power plant, including those that were in operation before August 7,
1962, if these units are co-located with one or more units that were
put in place within the 1962-1977 time period. These commenters
requested that we clarify that such pre-1962 units would not be BART-
eligible.
Some commenters asserted that our proposed approach is unworkable,
because the approach requires States to identify all emissions units
put in place between the 1962 and 1977. Some of these commenters
asserted that Congress intended that BART would apply only if entire
plants satisfy the statutory criteria. These comments suggested that
BART should apply only if an entire plant that is one of the 26 listed
source category types had been placed in operation at a discrete point
within the 15 year time period for BART eligibility. These commenters
asserted that our proposed guidelines, which involved the
identification and aggregation of individual emission units within the
1962-1977 time period, were inconsistent with Congress' intent. Other
comments suggested that EPA could improve implementation of the program
by covering discrete projects rather than individual emissions units. A
few commenters suggested that for purposes of identifying such discrete
projects, we consider using the term ``process or production unit''
that we used in hazardous air pollutant regulations under CAA section
112(g).
One commenter requested that the guidelines clarify that emissions
from ``linked'' emission units should not be considered in determining
BART eligibility. That is, even if changes in emissions from one unit
could affect the emissions from a ``linked'' unit that was not put in
place within the 1962-1977 time period, that would not affect whether
the ``linked'' unit was BART-eligible. Another commenter suggested that
the approach set forth in the guidelines for identifying BART-eligible
sources is inappropriate because the particular set of units identified
as BART-eligible will not necessarily ``provide a reasonable and
logical platform for the installation of controls.''
Other commenters stated that facilities that had been modified
after 1977 should not be included in the pool of sources subject to
BART. Such facilities, it was argued, already meet the BART
requirements because of the controls installed to meet the requirements
of PSD, NSR, or the NSPS.
Final rule. We disagree with the comments recommending that we
interpret the term ``in existence'' to refer to sources that are in
actual operation. The discussion of this term in Step 2 is based on the
regulatory definition which has been in place since 1980. The
guidelines reiterate this definition and provide examples of its
application. Interpreting the term ``in existence'' as suggested by
commenters would not be consistent with the plain language of the
regulations.
In the 2001 and 2004 proposed guidelines, we noted that ``the term
`in existence' means the same thing as the term `commence construction'
as that term is used in the PSD regulations.'' Commenters were critical
of this statement, claiming that EPA was unlawfully reinterpreting
section 169A in the guidelines. The statement in Step 2 of guidelines,
however, is not a reinterpretation of the term ``in existence,'' but
merely a statement noting that the definitions used in the visibility
regulations and the PSD regulations are essentially identical.
To the extent that commenters are claiming that the existing
regulatory definition of ``in existence'' is unlawful, EPA's
interpretation of this term in promulgating the 1980 regulations was a
reasonable one. First, it is worth noting that the regulations adopting
this interpretation of the term ``in existence'' were in effect in 1990
and implicitly endorsed by Congress in its 1990 amendments to the
CAA.\10\ Moreover, the definition at issue accurately reflects
Congress' intent that the BART provision apply to sources which had
been ``grandfathered'' from the new source review permit requirements
in parts C and D of title I of the CAA. For all the above reasons, we
are neither revising the regional haze regulations to change the
definition of ``in existence,'' nor adopting a strained interpretation
of the regulation in the guidelines.
---------------------------------------------------------------------------
\10\ See CAA section 193.
---------------------------------------------------------------------------
We agree with commenters that the definition of ``BART-eligible
source'' does not require States to find that all emission units at a
facility are subject to the requirement of the BART provisions if only
one part of the facility was built within the 1962-1977 time period. We
received comments on this issue in 2001 and clarified in 2004 that the
BART guidelines do not direct States to find that all boilers at a
facility are BART-eligible if one or more boilers at the facility were
put in place during the relevant time period. Under Step 2 of the
process for identifying BART-eligible sources set out in the
guidelines, States are required to identify only those boilers that
were put in place between 1962 and 1977. As explained in the preamble
to the 2004 reproposed guidelines, only these boilers are potentially
subject to BART.
[[Page 39112]]
We do not agree with those commenters claiming that Congress
clearly intended to apply BART only if an ``entire plant'' was put into
place between 1962 and 1977. Most of the BART source categories are
broad descriptions types of industrial facilities such as ``kraft pulp
mills,'' ``petroleum refineries'' or ``primary copper smelters.'' For
such source categories, the implication of commenters' argument would
that if any portion of the plant was in operation before August 7,
1962, then Congress intended to exempt the entire plant from BART. Such
an interpretation is problematic and inequitable. For example, under
this approach BART would not apply if a company chose to expand its
production by building a second production line at an existing line in
1965, but would apply if the same company chose to build the same
equipment at a greenfield site. Under the approach set forth in the
guidelines, such a production line would be treated similarly under
either set of facts. We do not believe that either the plain language
of the statute or the relevant legislative history indicate that
Congress intended for major-emitting sources of visibility-impairing
pollutants to be exempted from the BART requirements because a plant
contains some emission units that began operation before 1962.
Also, we disagree with the comment that modifications after 1977
should change an emissions' unit date of construction for purposes of
BART applicability. The commenter's suggestion that such sources
already meet BART requirements may be accurate, but does not provide a
basis for exempting the source from review. As we note in the
guideline, the review process will take into account the controls
already in place and the State may find that these controls are
consistent with BART.
We agree with the comments related to ``linked'' emission units.
The comment appears to address whether emissions from the ``linked''
units are considered in determining BART eligibility. In the
guidelines, we are focusing on only the emissions units that were put
in place during the 1962 to 1977 dates and the emissions from those
units. We agree that even if changes in emissions from one unit could
affect the emissions from a ``linked'' unit that was not put in place
within the 1962-1977 time period, this would not affect whether the
``linked'' unit was BART-eligible.
We disagree with commenters that the approach set forth in the
guidelines for identifying BART-eligible sources is inappropriate
because the particular set of units identified as BART-eligible will
not necessarily ``provide a reasonable and logical platform for the
installation of controls.'' We do not agree that this factor is
relevant to the identification of those emissions units which meet the
definition of BART-eligible source. Such factors are important in the
States' consideration of control strategies and options but do not
clearly relate to the first step of identifying those sources which
fall within one of 26 source categories, were built during the 15 year
window of time from 1962 to 1977, and have potential emissions of
greater than 250 tons per year. We do thus agree generally with the
commenter's recommendation of allowing States to consider the
particular history and control potential of units in determining BART,
but do not agree that it is relevant to the predicate question of
identifying the BART-eligible source.
Finally, the approach to identifying a ``BART-eligible source'' in
the guidelines is based on the definitions in the regional haze rule of
the relevant terms. For 750 MW power plants, States are required to
apply the definitions as set forth in the guidelines; for other
sources, States may adopt a different approach to the task of
identifying BART-eligible sources, so long as that approach is
consistent with the Act and the implementing regulations. In other
words, while the guidelines adopt an approach for large power plants
which involves the aggregation of all emissions units put into place
between 1962 and 1977, States have the flexibility to consider other
reasonable approaches to the question of identifying BART-eligible
sources for other source categories.
For 750 MW power plants, many of the issues identified by
commenters with the approach of looking at a facility on an emission
unit by emission unit basis do not exist. Unlike many types of
industrial processes, power plants consist generally of a discrete
number of very large emission units. For other types of facilities such
as kraft pulp mills or chemical process plants which may have many
small emission units that have undergone numerous changes, the
guidelines do not limit the ability of the States to approach the
question of identifying BART-eligible sources in ways which make sense
for the particular sources given their design and history.
Step 3: Compare the Potential Emissions to the 250 Ton/Yr Cutoff.
Background. Step 3 of the guidelines addresses the question of
whether the units identified in Steps 1 and 2 have emissions in excess
of the threshold for major sources set forth in section 169A(g)(7) of
the CAA. The guidelines pose the following questions to help the States
in determining whether the relevant emissions units have the potential
to emit in excess of the 250 tons per year threshold of any single
visibility-impairing pollutant:
(1) What pollutants should I address?
The 2001 proposed guidelines included the following list of
visibility-impairing pollutants: SO2, NOX,
particulate matter, volatile organic compounds (VOCs), and ammonia. We
proposed in 2001 and again in 2004 that States use PM10 as
the indicator for particulate matter. As explained in the guidelines,
there is no need to have separate 250 ton thresholds for
PM10 and PM2.5 because emissions of
PM10 include the components of PM2.5 as a subset.
In addition, because of various uncertainties associated with
regulating VOCs and ammonia, we requested comment in 2004 on the level
of discretion States should exercise in making BART determinations for
VOCs and took ammonia off the list of visibility-impairing pollutants.
In both proposals, we clarified that the 250 tons per year cutoff
applies to emissions on a pollutant by pollutant basis. In other words,
a source is subject to BART only if it emits at least 250 tons per year
of an individual visibility-impairing pollutant.
(2) What does the term ``potential'' emissions mean?
The proposed guidelines in 2001 and the reproposed guidelines in
2004 excerpt the definition of ``potential to emit'' from the
regulations at 40 CFR 51.301. As the definition makes clear, the
potential to emit of a source is calculated based on its capacity to
emit a pollutant taking into account its physical and operational
design. Under this definition, federally enforceable emission limits
may be taken into account in calculating a source's potential
emissions; however, emission limitations which are enforceable only by
State and local agencies, but not by EPA and citizens in Federal court,
cannot be used to limit a source's potential to emit for purposes of
the regional haze program.
(3) What is a ``stationary source?'
As explained above, States are required to make a BART
determination only for ``stationary sources'' of a certain size that
fall within one of 26 types of industrial categories listed in the
statute and that were built within a certain time frame. The regional
haze rule contains definitions that are relevant to the determination
of the emissions units that comprise a ``stationary source.'' First,
the regulations at 40 CFR 51.301
[[Page 39113]]
define ``stationary source'' as ``any building, structure, facility, or
installation which emits or may emit any air pollutant.'' Second, the
terms ``building, structure, or facility'' are defined in part based on
grouping pollutant-emitting activities by industrial category:
Building, structure, or facility means all of the pollutant-
emitting activities which belong to the same industrial grouping,
are located on one or more contiguous or adjacent properties, and
are under the control of the same person (or persons under common
control). Pollutant-emitting activities must be considered as part
of the same industrial grouping if they belong to the same Major
Group (i.e., which have the same two-digit code) as described in the
Standard Industrial Classification Manual, 1972 as amended by the
1977 Supplement (U.S. Government Printing Office stock numbers 4101-
0066 and 003-005-00176-0 respectively).
In the 2001 proposed guideline, we noted that support facilities,
i.e. facilities used to convey, store, or otherwise assist in the
production of the principal product, are considered to fall within the
same industrial grouping as the primary facility. To clarify this, in
2004 we proposed to add language to the guideline noting that emission
units at a plant, even if they are a ``support facility'' for purposes
of other programs, would not be subject to BART unless they were within
one of the 26 listed source categories and were built within the 1962
to 1977 time frame.
Discussion of ``What Pollutants Should I Address?''
Comments. PM10 as an indicator. Some comments questioned
the use of PM10 (which includes both coarse and fine
particulate matter) as the indicator for particulate matter. Commenters
noted that the coarse fraction, that is particulate matter between 10
and 2.5 micrograms in diameter, fundamentally differs compared to the
fine mass in how it interacts with light. Commenters suggested that
only the fine mass (PM2.5) component of particulate matter
is likely to contribute to visibility impairment. Accordingly, these
commenters recommended that the 250 ton cutoff for particulate matter
should be based upon emissions of PM2.5.
Ammonia. Many commenters addressed the exclusion of ammonia from
the list of visibility-impairing pollutants. A number of commenters,
primarily from industry but also from one state and one regional
planning organization, supported the exclusion of ammonia. These
commenters generally cited the complexity and variability of ammonia's
role in the formation of PM2.5 in the atmosphere, the
relative greater benefits of controlling NOX and
SO2, the uncertainties in the inventory of ammonia
emissions, and the inherent complexities of gauging the contribution of
potential ammonia reductions to improving visibility in Class I areas.
In addition, commenters noted that few, if any, point sources emit
ammonia in amounts that exceed the 250 ton per year threshold.
Other commenters, including a number of environmental groups and
several states, regional planning organizations, and industry
commenters, argued that ammonia should be included in the list of
visibility-impairing pollutants in the guidelines. In support of this
view, commenters cited evidence that ammonia is a known precursor to
PM2.5. One commenter noted that improvements are being made
to ammonia inventories and to the understanding of ammonia's role in
the formation of haze. Other commenters pointed to a National Park
Service (NPS) analysis of monitoring data that indicates that
visibility-impairment due to nitrate aerosol formation (to which
ammonia contributes) is of significant concern \11\ and to a 2003
direction to policy-makers from the North American Research Strategy
for Tropospheric Ozone (NARSTO) \12\ indicating that consideration of
control strategies needs to include ammonia in combination with other
precursors to particle formation. Many commenters also argued that EPA
should encourage or allow the States to consider ammonia in their
visibility protection plans, and noted that ammonia reductions could be
a cost-effective way to improve visibility under certain conditions.
---------------------------------------------------------------------------
\11\ See http://wrapair.org/forums/ioc/meetings/030728/index.html (specifically presentation by John Vimont, National Park
Service).
\12\ NARSTO, Particulate Matter Assessment for Policy Makers: A
NARSTO Assessment. P. McMurry, M. Shepherd, and J. Vickery, eds.
Cambridge University Press, Cambridge, England (2004).
---------------------------------------------------------------------------
Volatile Organic Compounds (VOCs). Several commenters responded to
our request for comments on whether States should treat VOCs in urban
areas differently from VOCs in rural areas. Environmental groups and a
few States argued that the current state of scientific knowledge does
not support a differentiation between urban and rural sources of VOCs.
One environmental commenter cited evidence that organic aerosols are a
major constituent of visibility-reducing aerosols and that VOCs are
important precursors to the formation of secondary organic aerosols.
One commenter also stated that VOCs may play a particularly significant
role in particle formation in those rural areas with significant nearby
sources of NOX. Commenters also cited evidence that the
contribution of VOC to particle formation likely varies widely in
different areas of the country, and argued that States should retain
flexibility to address local VOC sources if they determine that those
sources are contributors of concern.
Several industry commenters stated that more focus should be placed
on controlling VOCs in urban rather than rural areas. A few commenters
from industry argued that VOCs in rural areas have not been shown to be
a significant contributor to particle formation, and should be excluded
from the list of pollutants to be addressed in the BART process. One
argued that VOCs should be excluded from BART entirely based upon
uncertainties in the current state of knowledge, and a few argued that
VOCs from both power plants and rural sources should be excluded from
BART, based on low emissions and the cost of controls. One regional
planning organization requested that EPA clarify the definitions of
``urban'' and ``rural'' areas.
Final rule. PM10 as an indicator. While it is always
necessary to assess PM2.5 impacts, we agree with commenters
who stated that the coarse fraction is less efficient at light
scattering than fine particles, there is ample evidence that the coarse
fraction does contribute to visibility impairment.\13\ For example,
standard methods for calculating reconstructed light extinction
routinely include a calculation for the contribution to light
extinction from the coarse fraction, an implicit recognition that these
particles contribute measurably to visibility impairment.\14\ We do
recognize that coarse PM is likely to contribute more to regional haze
in arid areas than humid areas. We believe that, as the Grand Canyon
Visibility Transport Commission (GCTVC) recognized,\15\ States in the
arid West in particular should take the coarse fraction of particulate
matter into account in determining whether a source meets the threshold
for BART applicability.
---------------------------------------------------------------------------
\13\ See Fine particles: Overview of Atmospheric Chemistry,
Sources of Emissions, and Ambient Monitoring Data, Memorandum to
Docket OAR 2002-0076, April 1, 2005.
\14\ These methods are described at the following Web site:
http://vista.cira.colostate.edu/improve/Tools/ReconBext/reconBext.htm.
\15\ Grand Canyon Visibility Transport Commission,
Recommendations for Improving Western Vistas, Report to the U.S.
EPA, June 10, 1996.
---------------------------------------------------------------------------
Because long-range transport of fine particles is of particular
concern in the formation of regional haze, we also
[[Page 39114]]
believe that it is very important to estimate the PM2.5
fraction of direct particulate emissions as correctly as possible. In
addition, we believe that air quality modeling results will be more
meaningful provide a more accurate prediction of a source's impact on
visibility if the inputs account for the relative particle size of
directly emitted particulate matter (e.g. PM10 vs.
PM2.5).
States should consider whether their current test methods for
measuring particulate matter emissions from stationary sources account
for the condensible fraction of particulate matter and consider
revising any such stationary source test methods to account for the
condensible fraction of particulate emissions. See the source testing
technical support document (TSD) in the docket for this rule, which
discusses test methods for particulate matter in more detail.\16\
---------------------------------------------------------------------------
\16\ Fine particles: Overview of Source Testing Approaches,
Memorandum to Docket OAR 2002-0076, April 1, 2005.
---------------------------------------------------------------------------
Ammonia. In regard to ammonia, we believe there is sufficient
uncertainty about emission inventories and about the potential efficacy
of control measures from location to location such that the most
appropriate approach for States to take is a case-by-case approach.
There are scientific data illustrating that ammonia in the atmosphere
can be a precursor to the formation of particles such as ammonium
sulfate and ammonium nitrate; \17\ however, it is less clear whether a
reduction in ammonia emissions in a given location would result in a
reduction in particles in the atmosphere and a concomitant improvement
in visibility. In other words, the question of whether ammonia
contribute to visibility impairment in a specific instance can be a
difficult one.
---------------------------------------------------------------------------
\17\ See Fine particles: Overview of Atmospheric Chemistry,
Sources of Emissions, and Ambient Monitoring Data, Memorandum to
Docket OAR 2002-0076, April 1, 2005.
---------------------------------------------------------------------------
It may be that States will not be faced often with the question of
addressing ammonia in making BART determinations. As noted above,
States are required to make BART determinations only for stationary
sources that fall within certain industrial categories. The types of
sources subject to the BART provisions are not typically significant
emitters of ammonia. Because of this, it is unlikely that including
ammonia on the list of visibility-impairing pollutants in the BART
guidelines would have much impact on the States' determinations of
whether a source is BART-eligible. Thus, while ammonia can contribute
to visibility impairment, we believe the decision whether to consider
ammonia as a visibility-impairing pollutant in a specific case where a
potential BART source actually emits more than 250 tons per year of
ammonia is best left to the State.
VOCs. Organic compounds can be categorized according to their
varying degrees of volatility: highly reactive, volatile compounds with
six or fewer carbon atoms which indirectly contribute to PM formation
through the formation of oxidizing compounds such as the hydroxyl
radical and ozone; semivolatile compounds with between seven and 24
carbon atoms which can exist in particle form and can readily be
oxidized to form other low volatility compounds; and high molecular
weight organic compounds--those with 25 carbon atoms or more and low
vapor pressure--which are emitted directly as primary organic particles
and exist primarily in the condensed phase at ambient temperatures. The
latter organic compounds are considered to be primary PM2.5
emissions and not VOCs for BART purposes.
Current scientific and technical information shows that
carbonaceous material is a significant fraction of total
PM2.5 mass in most areas and that certain aromatic VOC
emissions such as toluene, xylene, and trimethyl-benzene are precursors
to the formation of secondary organic aerosol.\18\ However, while
progress has been made in understanding the role of VOCs in the
formation of organic PM, this relationship remains complex, and issues
such as the relative importance of biogenic versus anthropogenic
emissions remain unresolved.
---------------------------------------------------------------------------
\18\ Ibid.
---------------------------------------------------------------------------
Therefore we believe that the best approach for States to follow in
considering whether VOC emissions are precursors to PM2.5
formation is a case-by-case approach. States should consider, in
particular, whether a source's VOC emissions are those higher-carbon
VOCs that are more likely to form secondary organic aerosols. In
addition, given the variable contribution of a given amount of VOC
emissions to PM2.5 formation, States may also wish to
exercise discretion in considering only relatively larger VOC sources
to be BART-eligible.
After careful consideration of the comments, we agree with
commenters who assert that EPA should not suggest a general distinction
between the relative contributions of urban and rural VOC emissions to
particle formation. The state of knowledge in this area is complex and
rapidly evolving. Monitoring data in the East \19\ suggest that there
may be a greater contribution to particle formation in urban areas from
VOCs as compared to rural areas, but we recognize that further research
is needed to better determine the extent of the contribution of
specific VOC compounds to organic PM mass. We do not agree, however,
with commenters who make the blanket assertion that rural VOCs are not
a significant contributor to particle formation, as it is possible that
in specific areas, such as where NOX emissions are high,
rural anthropogenic VOCs could potentially play a significant role.
---------------------------------------------------------------------------
\19\ Ibid.
---------------------------------------------------------------------------
Discussion of the Term ``Potential'' Emissions
Comments. A number of commenters were critical of the restriction
in the regional haze rule that allows States to credit federally
enforceable limitations on emissions but not limitations that are
enforceable only by States and local agencies. These commenters
believed that this restriction had been rejected by the D.C. Circuit
for a number of other EPA regulations and noted that EPA has developed
policies that currently credit state-enforceable limits. The comments
recommended that EPA issue guidance consistent with what commenters
claimed were current policies for other regulations. In addition, we
received comments arguing that in determining whether a source is a
major stationary source, the States should consider a source's actual--
rather than potential--emissions. These commenters stated that using a
source's potential emissions overstates a source's actual emissions and
impacts on visibility.
Final rule. CAA section 169A(g)(7) defines a ``major stationary
source'' as a source with the potential to emit 250 tons or more any
pollutant. Based inter alia on that statutory definition, EPA's
implementing regulations define BART-eligible sources as those with the
potential to emit 250 tons or more of any air pollutant. As these
definitions clearly require consideration of a source's potential
emissions, the guidelines state that a State should determine whether a
source's potential emissions exceed the 250 ton threshold in
determining whether the source is BART-eligible.
As explained in the 2001 and 2004 proposed guidelines, the regional
haze regulations define ``potential to emit.'' The guidelines repeat
that regulatory definition and provide an example illustrating its
application. EPA did not propose to change the definition in 2001 or
2004, but merely highlighted the
[[Page 39115]]
current definition in 40 CFR 51.301. Although we noted in the 2001
proposed guidelines that we expected to undertake a rulemaking to
determine whether only federally enforceable limitations should be
taken into account in the regional haze program definition, we have not
yet begun the process for such a rulemaking. However, we consider the
comments criticizing EPA's definition of ``potential to emit'' as a
request for reconsideration of the visibility regulations and will take
these requests into account in determining any future rulemaking
efforts to address the general definition of ``potential to emit.'' For
the time being, we believe that States may consider federally
enforceable limits or emissions limitations in State permits, which are
enforceable under State law, in determining a source's ``potential to
emit.''
Discussion of What Emissions Units Should Be Considered Part of a
``Stationary Source''
Comments. A number of comments in 2001 expressed concern with our
statement that a ``support facility'' should be grouped with a primary
facility in determining which emissions units belong to the same
industrial grouping. These comments generally coincided with comments
discussed above that EPA should determine BART on a plantwide basis,
rather than by aggregating emissions units. Commenters on the 2004
reproposal noted with approval the clarification that ``support
facilities'' should only be considered BART-eligible if these units
themselves were both constructed within the 1962-1977 time frame and
fell within one of the listed source categories.
Two commenters felt that we should more clearly define the BART-
eligible source, either by identifying emission units within source
categories, or by somehow accounting for the specific set of emission
units, within the fenceline, to which controls would logically apply.
Final rule. The guidelines continue to note that the definition of
``building, structure or facility'' in the regional haze rule is based
upon aggregating emissions units within the same industrial grouping.
This discussion in the guidelines is consistent with the language in
the definition of ``building, structure or facility'' in the regional
haze rule which contains a specific reference to the 2-digit SIC
classifications. The BART guidelines refer to this definition and
explain how 2-digit SIC codes are used in determining the scope of BART
for a given plantsite. (In the rare situation where industrial
groupings in separate 2-digit SIC codes exist at a single plant site,
then there would be more than one separate ``stationary source''
present. In that situation, each ``stationary source'' should be looked
at individually for purposes of determining BART-eligibility.)
We agree that more clarity is needed to account for situations
where a specific set of units constitute the logical set to which BART
controls would apply. The CAA requires BART at certain major stationary
sources. Accordingly we believe it could be appropriate, at the BART
determination step, for States to allow sources to ``average''
emissions across a set of BART-eligible emission units within a
fenceline, so long as the amount of emission reductions from each
pollutant being controlled for BART would be at least equal to those
reductions that would be obtained by simply controlling each unit. We
have added language to the guidelines to this effect.
Step 4: Identify the Emission Units and Pollutants That Constitute the
BART-Eligible Source
Background. The final step in identifying a ``BART-eligible
source'' is to use the information from the previous three steps to
identify the universe of equipment that makes up the BART-eligible
source. The 2001 and 2004 proposed BART guidelines stated that if the
emissions from the list of emissions units at a stationary source
exceed a potential to emit of 250 tons per year for any individual
visibility-impairing pollutant, then that collection of emissions units
is a BART-eligible source. The guidelines also stated that a BART
analysis would be required for each visibility-impairing pollutant
emitted from this collection of emissions units.
In the 2004 reproposed BART guidelines, we noted that we believed
that section 169A(b)(2)(A) of the CAA requires a State to undertake a
BART analysis for ``any'' visibility-impairing pollutant emitted by a
BART-eligible source, regardless of the amount emitted. We proposed,
however, to provide the States with the flexibility to identify de
minimis levels for pollutants at BART-eligible sources, but limited
that flexibility so that any such de minimis levels could not be higher
than those used in the PSD program: 40 tons per year for
SO2, NOX, and VOC, and 15 tons per year from
PM10. We requested comment on this provision and on the use
of de minimis values.
Discussion of Whether To Include All Emitted Visibility-Impairing
Pollutants in the BART Analysis
Comments. A number of commenters supported the concept of including
all pollutants in the BART analysis once an individual pollutant
triggers the BART review. Other commenters, although supportive of the
concept generally, recommended that we should add the pollutants
together before the comparison with the threshold.
A number of commenters disagreed with EPA's conclusion that the CAA
requires States to make a BART determination for any visibility-
impairing air pollutant emitted by a BART eligible source. These
commenters stated that undertaking a BART analysis for all pollutants
emitted by a major stationary source is an unnecessary administrative
burden with minimal environmental benefit. Commenters argued that
Congress intended for BART to apply only to those pollutants for which
a source is major. Commenters accordingly recommended that the 250 ton
per year threshold apply to each pollutant emitted by a source and that
BART apply only to those pollutants which meet this threshold. A number
of these commenters argued alternatively that only those pollutants
from a source demonstrated, individually, to cause or contribute to
visibility impairment are required to go through a BART determination.
Final rule. We disagree with the comment that emissions of
different visibility-impairing pollutants must be added together to
determine whether a source exceeds the 250 ton per year threshold. The
CAA, in section 169A(g)(7), defines a ``major stationary source'' as
one with the potential to emit 250 tons or more of ``any pollutant.''
We disagree with comments that the BART analysis is required only
for those pollutants that individually exceed the 250 ton per year
threshold. Section 169A(b)(2)(A) specifically requires States to submit
SIPs that include a requirement that a major stationary source
which, as determined by the State * * * emits any air pollutant
which may reasonably be anticipated to cause or contribute to any
impairment of visibility in any [Class I area], shall procure,
install, and operate * * * the best available retrofit technology,
as determined by the State * * * for controlling emissions from such
source for the purpose of eliminating or reducing any such
impairment.
The regional haze regulations similarly require that the States submit
a SIP that contains
[[Page 39116]]
A determination of BART for each BART-eligible source in the State
that emits any air pollutant which may reasonably be anticipated to
cause or contribute to any impairment of visibility in any mandatory
Class I Federal area.
40 CFR 51.308(e)(1)(ii). Nothing in these statutory or regulatory
requirement suggests that the BART analysis is limited to those
pollutants for which a source is considered major. At best, these
provisions can be read as requiring a BART determination only for those
emissions from a specific source which do, in fact, cause or contribute
to visibility impairment in a particular Class I area, or which could
reasonably be anticipated to do so. Commenters, however, have not
presented any evidence that as a general matter emissions of less than
250 tons per year of PM2.5, SO2, or other
visibility-impairing pollutants from potential BART sources do not
``cause or contribute to any impairment of visibility'' in any of the
Class I areas covered by the regional haze rule. As there is no such
evidence currently before us, there is no basis to conclude that the
States are required to make BART determinations only for those
pollutants emitted in excess of 250 tons per year.
At the same time, we agree with certain commenters that the CAA
does not require a BART determination for any visibility impairing
pollutant emitted by a source, regardless of the amount. After
reviewing the language of the Act and the comments received, we have
concluded that our interpretation of the relevant language in section
169A(b)(2)(A) of the Act in the 2004 proposed guidelines is not
necessarily the best reading of the BART provisions. Section
169A(b)(2)(A) of the Act can be read to require the States to make a
determination as to the appropriate level of BART controls, if any, for
emissions of any visibility impairing pollutant from a source. Given
the overall context of this provision, however, and that the purpose of
the BART provision is to eliminate or reduce visibility impairment, it
is reasonable to read the statute as requiring a BART determination
only for those emissions from a source which are first determined to
contribute to visibility impairment in a Class I area.
The interpretation of the requirements of the regional haze program
reflected in the discussion above does not necessitate costly and time-
consuming analyses. Consistent with the CAA and the implementing
regulations, States can adopt a more streamlined approach to making
BART determinations where appropriate. Although BART determinations are
based on the totality of circumstances in a given situation, such as
the distance of the source from a Class I area, the type and amount of
pollutant at issue, and the availability and cost of controls, it is
clear that in some situations, one or more factors will clearly suggest
an outcome. Thus, for example, a State need not undertake an exhaustive
analysis of a source's impact on visibility resulting from relatively
minor emissions of a pollutant where it is clear that controls would be
costly and any improvements in visibility resulting from reductions in
emissions of that pollutant would be negligible. In a scenario, for
example, where a source emits thousands of tons of SO2 but
less than one hundred tons of NOX, the State could easily
conclude that requiring expensive controls to reduce NOX
would not be appropriate. In another situation, however, inexpensive
NOX controls might be available and a State might reasonably
conclude that NOX controls were justified as a means to
improve visibility despite the fact that the source emits less than one
hundred tons of the pollutant. Moreover, as discussed below, we are
revising the regional haze regulations to allow the States to exempt de
minimis emissions of SO2, NOX, and
PM2.5 from the BART determination process which should help
to address the concerns of certain commenters associated with the
burden of a broad BART analysis.
De minimis levels
Comments. Many commenters agreed that we should establish de
minimis levels for individual pollutants in order to allow States and
sources to avoid BART determinations for pollutants emitted in
relatively trivial amounts. Many commenters suggested that States would
be unlikely to impose emission limits for pollutants emitted at the
proposed de minimis levels because it would not be cost-effective to do
so and such emission reductions could not be expected to produce any
perceptible improvements in visibility. Several commenters agreed that
the pollutant coverage requirements for BART eligibility should be
consistent with those for the PSD program, but others argued that BART
should be required only for pollutants emitted in amounts greater than
250 tons per year. Commenters also noted that the guidelines were not
clear as to whether the de minimis provision would apply on a plant-
wide or unit by unit basis. A few commenters also noted that the final
guidelines should clarify where in the BART determination process de
minimis levels may be used.
Other commenters opposed the use of de minimis exemptions. These
commenters argued that it would be unreasonable to rule categorically
that a certain level of emissions had a trivial impact on visibility
without assessing the impacts of these emissions in particular
circumstances. These commenters argued that States should consider the
emissions of all visibility-impairing pollutants in a BART
determination regardless and that, consequently, there should be no de
minimis levels.
Final rule. As proposed in 2004, we believe that it is reasonable
to give States the flexibility to establish de minimis levels so as to
allow them to exempt from the BART determination process pollutants
emitted at very low levels from BART-eligible sources. As explained by
the D.C. Circuit, ``categorical exemptions from the requirements of a
statute may be permissible `as an exercise of agency power, inherent in
most statutory schemes, to overlook circumstances that in context may
fairly be considered de minimis.' '' \20\ The ability to create de
minimis exemptions from a statute is a tool to be used in implementing
the legislative design.\21\
---------------------------------------------------------------------------
\20\ EDF et al. v. EPA, 82 F.3d 451, 466 (D.C. Cir. 1996) citing
Alabama Power v. Costle, 636 F.2d 323 (D.C. Cir. 1979).
\21\ Id.
---------------------------------------------------------------------------
The intent of Congress in requiring controls on emissions from
certain major stationary sources was to eliminate or reduce any
anticipated contribution to visibility impairment from these sources.
This, as section 169A(b)(2)(A) states, is the ``purpose'' of BART. In
making a determination as to the appropriate level of controls,
however, the States are required to take into account not only the
visibility benefits resulting from imposing controls on these sources
but also the costs of complying with the BART provision. The BART
provision is accordingly designed to ensure that the States take into
consideration all emissions of certain stationary sources in making a
BART determination, but also to provide States with the flexibility to
include the costs and benefits of controlling these sources in the
calculus of determining the appropriate level of BART.
We believe it would be permissible for States to create de minimis
levels at a low level. If a State were to undertake a BART analysis for
emissions of less than 40 tons of SO2 or NOX or
15 tons of PM10 from a source, it is unlikely to result in
anything but a trivial improvement in visibility. This is
[[Page 39117]]
because reducing emissions at these levels would have little effect on
regional emissions loadings or visibility impairment. We believe most
States would be unlikely to find that the costs of controlling a few
tons of emissions were justified. Because the overall benefits to
visibility of requiring BART determinations for emissions of less than
the de minimis levels would be trivial, we are amending the regional
haze rule to make clear that the States have this flexibility.
The de minimis levels discussed today apply on a plant-wide basis.
Applying de minimis levels on a unit by unit basis as suggested by
certain commenters could exempt hundreds of tons of emissions of a
visibility-impairing pollutant from BART analysis. In at least some of
the twenty-six source categories covered by the BART provisions, a
single control device can be used to control emissions from multiple
units. Thus, it is possible that while emissions from each unit are
relatively trivial, the costs of controlling emissions from multiple
units might be cost-effective in light of the BART-eligible source's
total emissions of the pollutant at issue. States should consider the
control options in such situations and determine the appropriate
approach for the specific source.
We are revising the regional haze rule to provide States with the
ability to establish de minimis levels up to the levels proposed in
2004. We believe States may, if they choose, exclude from the BART
determination process potential emissions from a source of less than
forty tons per year of SO2 or NOX, or 15 tons per
year for PM10. (Note also that for sources that are BART-
eligible for one pollutant, we also believe that States could allow
those sources to model the visibility impacts of pollutants at levels
between de minimis and 250 tons in order to show that the impact is
negligible and should be disregarded. See section D below). In the
guidelines, we include this as part of the BART determination in
section IV of the guidelines. (We note that these emission levels
represent the maximum allowable de minimis thresholds--States retain
their discretion to set the thresholds at lesser amounts of each
pollutant, or to not provide any pre-determined de mininis levels.) We
believe that this approach is the clearest method for exempting trivial
emissions from the BART determination process. Alternatively, States
may find it useful to exclude de minimis emissions in identifying
whether a source is subject to BART in section III of the guidelines.
Either approach is consistent with the regulation issued in this rule.
D. How To Determine Which BART-eligible Sources Are ``Subject to BART''
Cause or Contribute
Background. Under section 169A(b)(2)(A) of the Act, each State must
review its BART eligible sources and determine whether they emit ``any
air pollutant which may reasonably be anticipated to cause or
contribute to any impairment of visibility in [a Class I] area.'' If a
source meets this threshold, the State must then determine what is BART
for that source.
Proposed rule. In the reproposed guidelines, we identified three
options for States to use in determining which BART-eligible sources
meet the test set forth in section 169A(b)(2)(A) of the CAA. To
determine whether a BART-eligible source is ``reasonably anticipated to
cause or contribute to visibility impairment,'' the first proposed
option was that a State could choose to consider the collective
contribution of emissions from all BART-eligible sources and conclude
that all BART-eligible sources within the State are ``reasonably
anticipated to cause or contribute'' to some degree of visibility
impairment in a Class I area. The preamble to the 1999 regional haze
rule explains at length why we believe that looking to the collective
contribution of many sources over a broad area is a reasonable
approach, and we explained in the 2004 reproposed guideline that we
believed that a State's decision to use a cumulative analysis at this
stage of the BART determination process would be consistent with the
CAA and the findings of the D.C. Circuit in American Corn Growers.
The second proposed option was to allow a State to demonstrate,
using a cumulative approach, that none of its BART-eligible sources
contribute to visibility impairment. Specifically, we proposed to
provide States with the option of performing an analysis to show that
the full group of BART-eligible sources in a State cumulatively do not
cause or contribute to visibility impairment in any Class I areas.
As a third option, we proposed that a State may choose to determine
which sources are subject to BART based on an analysis of each BART-
eligible source's individual contribution. We labeled this option as an
``Individualized Source Exemption Process,'' and proposed that States
use an air quality model to determine an individual source's
contribution to visibility impairment, calculated on a 24 hour basis,
using allowable emissions, and compared to an established threshold.
Comments. Several commenters expressed the view that EPA was
misinterpreting the American Corn Growers case to allow the States to
apply a collective contribution test in determining whether BART-
eligible sources are subject to BART. These commenters took the
position that, because this approach does not allow for a source to
show that it does not individually cause or contribute to visibility
impairment, it is incompatible with the language of section
169A(b)(2)(A)of the Act. They argued that EPA should modify the
provisions in the proposed rule to ensure that an individual source is
afforded the opportunity to conduct an analysis to demonstrate that its
emissions do not impair visibility in any Class I area. Conversely,
several commenters indicated that the option to determine that all
potential BART sources contribute to regional haze should be the
starting point of determining BART eligibility.
Many industry commenters and some States supported the second
proposed option which would allow a State to demonstrate through an
analysis of the collective contribution of all its BART-eligible
sources that none of these sources contribute to visibility impairment.
Several of these commenters added, however, that if this cumulative
analysis were to show a contribution, then, consistent with the
decision in American Corn Growers, the State must allow each individual
source to demonstrate that its own emissions do not, by themselves,
contribute to the problem of visibility impairment. One commenter
requested clarification on what visibility threshold a State should use
in determining that no sources are reasonably anticipated to cause or
contribute to any impairment in a Class I area.
A number of commenters supported the third option for determining
BART applicability based on an analysis of source-specific effects on
visibility. However, many of the commenters stated that the CAA
requires that the States either conduct such an analysis in determining
those sources subject to BART, or allow an individual source to make a
showing that it does not cause or contribute to visibility impairment.
In addition, although supportive of the general notion of allowing for
an exemption process for BART-eligible sources, several commenters
stated that the third option contained burdensome modeling
requirements, and that States need a more flexible, straightforward,
[[Page 39118]]
and less costly method to make the ``cause or contribute''
determination.
Several environmental groups commented that the proposed options
potentially go too far in allowing sources to be exempted from the BART
requirements. These commenters asserted that EPA should clarify that
States may not allow a BART-eligible source to avoid the BART
requirements without an affirmative demonstration by the State, or by
the source, showing that the source does not emit any air pollutant
which may reasonably be anticipated to cause or contribute to any
impairment of visibility in a Class I area. Absent such a
demonstration, they argue, a State may not choose to waive the
requirement to conduct a BART review of the source.
Final rule. The final BART guidelines adopt the general approach
contained in the reproposal, providing the States with several options
for identifying the sources subject to BART. The final BART guidelines
describe the options contained in the reproposal as well as one new
option. The discussion of options in the final guidelines are
structured somewhat differently from the reproposal, and the options
are explained in greater detail. The guidelines reaffirm that a State
may choose to consider all BART-eligible sources to be subject to BART,
and to make BART determinations for all its BART-eligible sources.\22\
For States that choose to consider exempting some or all of their BART-
eligible sources from review, the guidelines then discuss three options
that States may use to determine whether its sources are ``reasonably
anticipated to cause or contribute'' to visibility impairment at a
Class I area. Options 1 and 3 are similar to options in the 2004
reproposal; under option 1, States may use an individual source
attribution approach, while option 3 provides the States with an
approach for demonstrating that no sources in a State should be subject
to BART. Option 2 is new; it is an approach for using model plants to
exempt individual sources with common characteristics.
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\22\ States choosing this approach should use the data being
developed by the regional planning organizations, or on their own,
as part of the regional haze SIP development process to make the
showing that the State contributes to visibility impairment in one
or more Class I areas.
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Threshold for visibility impact. One of the first steps in
determining whether sources cause or contribute to visibility
impairment for purposes of BART is to establish a threshold (quantified
in units called ``deciviews'') against which to measure the visibility
impact of one or more sources. We believe that a single source that is
responsible for a 1.0 deciview change or more should be considered to
``cause'' visibility impairment; a source that causes less than a 1.0
deciview change may still contribute to visibility impairment and thus
be subject to BART.
The guidelines note that because of varying circumstances affecting
different Class I areas, the appropriate threshold for determining
whether a source ``contributes to any visibility impairment'' for the
purposes of BART may reasonably differ across States. Although the
appropriate threshold may vary, the Guidelines state that the
contribution threshold used for BART applicability should not be higher
than 0.5 deciviews. We discuss threshold issues in greater detail in
the subsection immediately following this one, entitled Metric for
Visibility Degradation.
Pollutants
The guidelines direct that States should look at SO2,
NOX, and direct particulate matter (PM) emissions in
determining whether sources cause or contribute to visibility
impairment, including both PM10 and PM2.5.
Consistent with the approach for identifying BART-eligible sources,
States do not need to consider less than de minimis emissions of these
pollutants from a source.
States may use their best judgement to determine whether VOC or
ammonia emissions are likely to have an impact on visibility in an
area. In addition, they may use PM10 or PM2.5 as
an indicator for PM2.5 in determining whether a source is
subject to BART. In determining whether a source contributes to
visibility impairment, however, States should distinguish between the
fine and coarse particle components of direct particulate emissions.
Although both fine and coarse particulate matter contribute to
visibility impairment, the long-range transport of fine particles is of
particular concern in the formation of regional haze. Air quality
modeling results used in the BART determination will provide a more
accurate prediction of a source's impact on visibility if the inputs
into the model account for the relative particle size of any directly
emitted particulate matter (i.e. PM10 vs. PM2.5).
We believe that PM10 is likely to contribute more to
regional haze in arid areas than humid areas. As the Grand Canyon
Visibility Transport Commission (GCTVC) recognized,\23\ States in the
arid West, in particular, will need to take the coarse fraction of
particulate matter into account in determining whether a source meets
the threshold for BART applicability.
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\23\ Grand Canyon Visibility Transport Commission,
Recommendations for Improving Western Vistas, Report to the U.S.
EPA, June 10, 1996.
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Option 1. We agree with commenters supporting the use of an
individual source analysis in determining if a BART-eligible source
causes or contributes to visibility impairment. Consistent with
American Corn Growers, this option provides a method for a State to
evaluate the visibility impact from an individual source and show that
the source is not reasonably anticipated to cause or contribute to
visibility degradation in a Class I area and thus may be exempt from
BART. (Note also that an individual source analysis is used to inform
the BART determination). In general, a dispersion model is used to
assess the visibility impact from a single source, and that impact is
compared to a threshold which is determined by the State. The threshold
(quantified in deciviews) is the numerical metric that is used to
define ``cause or contribute''; if a source's impact is below the
threshold, a State may exempt the source from BART; otherwise the
source would be subject to BART.
We discuss specific issues on the individualized source attribution
process, including changes since proposal and issues raised by
commenters, in the subsections immediately following this one: Metric
for visibility degradation; Use of CALPUFF for visibility modeling; The
use of natural conditions in determining visibility impacts for
reasonable progress and comparison to threshold values; Modeling
protocol; and Alternatives for determining visibility impacts from
individual sources.
Option 2. In the final guideline, we describe a modified approach,
using model plants based on representative sources sharing certain
characteristics, that the States may use to simplify the BART
determination process, either to exempt (individually or as a group)
those small sources that are not reasonably anticipated to cause or
contribute to visibility impairment, or to identify those large sources
that clearly should be subject to BART review. States could use the
CALPUFF model, for example, to estimate levels of visibility impairment
associated with different combinations of emissions and distances to
the nearest Class I area. In carrying out this approach, the State
could then reflect groupings of specific types of sources with
important common characteristics, such as emissions, stack heights and
plume characteristics, and develop ``composite model plants.'' Based on
CALPUFF
[[Page 39119]]
analyses of these model plants, a State may find that certain types of
sources are clearly reasonably anticipated to cause or contribute to
visibility impairment. Conversely, representative plant analyses may
show that certain types of sources are not reasonably anticipated to
cause or contribute to visibility impairment. Based on the modeling
results, a State could exempt from BART all sources that emit less than
a certain amount per year and that are located a certain distance from
the nearest Class I area.
Our analyses of visibility impacts from model plants provide a
useful example of the type of analyses that might be used to exempt
categories of sources from BART.\24\ Based on our model plant analysis,
EPA believes that a State could reasonably choose to exempt sources
that emit less than 500 tons per year of NOX or
SO2 (or combined NOX and SO2), as long
as they are located more than 50 kilometers from any Class I area; and
sources that emit less than 1000 tons per year of NOX or
SO2 (or combined NOX and SO2) that are
located more than 100 kilometers from any Class I area.
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\24\ Supplement to CALPUFF Analysis in Support of the June 2005
Changes to the Regional Haze Rule, U.S. Environmental Protection
Agency, June 15, 2005, Docket No. OAR-2002-0076.
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In our analysis, we developed two model plants (a EGU and a non-
EGU), with representative plume and stack characteristics, for use in
considering the visibility impact from emission sources of different
sizes and compositions at distances of 50, 100 and 200 kilometers from
two hypothetical Class I areas (one in the East and one in the West).
Because the plume and stack characteristics of these model plants were
developed considering the broad range of sources within the EGU and
non-EGU categories, they do not necessarily represent any specific
plant. However, the results of these analyses may be instructive in the
development of an exemption process for groups of BART-eligible
sources, without modeling each of these sources individually.
States may want to conduct their own model plant analysis that take
into account local, regional, and other relevant factors (such as
meteorology, sulfur dioxide, nitrogen dioxide, and ammonia). If so, you
may want to consult your EPA Regional Office to ensure that any
relevant technical issues are resolved before you conduct your
modeling.
In preparing our hypothetical examples, we have made a number of
assumptions and exercised certain modeling choices; some of these have
a tendency to lend conservatism to the results, overstating the likely
impacts, while others may understate the modeling results. On balance,
when all of these factors are considered, we believe that our examples
reflect realistic treatments of the situations being modeled.\25\ A
summary of the more significant elements and their implications is
provided below.
\25\ CALPUFF Analysis in Support of the June 2005 Changes to the
Regional Haze Rule, U.S. Environmental Protection Agency, June 15,
2005, Docket No. OAR-2002-0076.
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Features of the modeling examples which may understate visibility
impacts
An annual emission rate was used for the example modeling
(e.g. 10,000 TPY divided by 365 days divided by 24 hours). ``Real
world'' sources have variable emission rates, and in any 24 hour period
may be operating well above the annual rate.
The monthly average relative humidity was used, rather
than the daily average humidity, and would contribute to lowering the
peak values in daily model averages.
A 24-hour average was calculated from modeled hourly
visibility impacts, reducing the impact of any one particular hour that
could be higher due to a number of meteorological effects.
Features of the modeling examples which may overstate visibility
impacts
We located receptors using a grid of concentric circles
for distances of 50, 100 and 200 km. A receptor was placed every 10
degrees around each circle, and highest impacts were reported
regardless of direction from the source. In actuality, receptors would
be located only in the Class I area, or in only one direction from the
source.
We used simplified chemistry (i.e. for conversion of
SO2 and NOX to fine particles) and disperson
techniques which tend to overstate model impacts.
Special care should be used to ensure that the criteria used in the
modeling are appropriate for a given State. Our modeling may not be
appropriate for every region of the country, due to the unique
characteristics of different Class I areas and varying meteorological
and geographical conditions in different regions. In addition, States
may want to design their own model plants taking into account the types
of sources at issue in their region.
Option 3. Under the BART guidelines, a State may consider exempting
all its BART-eligible sources from BART by conducting analyses that
show that all of the emissions from BART-eligible sources in their
State, taken together, are not reasonably anticipated to cause or
contribute visibility impairment. To make such a showing, a State could
use CALPUFF or another appropriate dispersion model to evaluate the
impacts of individual sources on downwind Class I areas, aggregating
those impacts to determine the collective contribution from all-BART
eligible sources in the State. A State with a sufficiently large number
of BART-eligible sources could also make such a showing using a
photochemical grid model.\26\
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\26\ For regional haze applications, regional scale modeling
typically involves use of a photochemical grid model that is capable
of simulating aerosol chemistry, transport, and deposition of
airborne pollutants, including particulate matter and ozone.
Regional scale air quality models are generally applied for
geographic scales ranging from a multi-state to the continental
scale. Because of the design and intended applications of grid
models, they may not be appropriate for BART assessments, so States
should consult with the appropriate EPA Regional Office prior to
carrying out any such modeling.
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We agree with commenters who pointed out that the option of
allowing a State to demonstrate that the full group of BART-eligible
sources in the State do not contribute to visibility impairment would,
by default, satisfy an individual source contribution assessment.
Commenters have not shown any reason to believe that if the sum total
of emissions from the BART-eligible sources in a State do not ``cause
or contribute'' to visibility impairment in any Class I area, that
emissions from one such source will meet the threshold for BART
applicability. A State following this approach accordingly need not
undertake an affirmative demonstration based on a source by source
analysis of visibility impacts to find that its sources are not subject
to BART.
Metric for Visibility Degradation
Background. The 2004 reproposed guidelines contained a proposed
threshold for the States to use in determining whether an individual
source could be considered to cause visibility impairment in a Class I
area. We proposed a 0.5 deciview change relative to natural background
conditions,\27\ as a numerical threshold for making this
determination.\28\
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\27\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, ( U.S. Environmental Protection Agency,
September 2003. http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf. Natural background conditions, expressed in
deciviews, are defined for each Class I area. EPA has issued
guidance for estimating natural background conditions which has
estimates of default conditions as well as measures to develop
refined estimates of natural conditions.
\28\ In the proposal we noted that a 0.5 deciview change in
visibility is linked to ``perceptibility,'' or a just noticeable
change in most landscapes. National Acid Precipitation Assessment
Program (NAPAP), Acid Deposition: State of Science and Technology
Report 24, Visibility: Existing and Historical Conditions--Causes
and Effects (Washington, DC, 1991) Appendix D at 24-D2 (``changes in
light extinction of 5 percent will evoke a just noticeable change in
most landscapes''). Converting a 5 percent change in light
extinction to a change in deciviews yields a change of approximately
0.5 deciviews.
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[[Page 39120]]
We proposed the CALPUFF model as the preferred approach for
predicting whether a single source caused visibility impairment if the
modeled results showed impacts from the source that exceeded the
threshold on any given day during a five-year period. We also proposed
that if a source had an estimated impact on visibility of less than 0.5
deciviews, a State could choose to exempt the source from further BART
analysis.
Comments. We received numerous comments supporting the proposed
threshold. A number of commenters stated that the 0.5 deciview
threshold is appropriate given the low triggering threshold for
applicability established by Congress, and that the literature supports
it as the minimum level of perceptibility. Some commenters cited
published documentation supporting their assertions that a minimum
change in deciviews necessary for perceptibility is 0.5 deciviews.\29\
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\29\ Ibid.
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Other commenters criticized the threshold as too low. They stated
that a change of 0.5 deciviews is inconsistent with language in the
regional haze rule pointing to 1.0 deciview as the appropriate
perceptibility threshold, and they cited more recent literature
justifying perceptibility as greater than a change of 1 deciview.\30\
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\30\ Henry, R.C., Just-Noticeable Differences in Atmospheric
Haze, Journal of the Air & Waste Management Association, 52:1238-
1243, October 2002.
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One commenter said that we should allow States and regional
planning organizations (RPOs) the flexibility to determine appropriate
visibility-impact thresholds in light of current knowledge about a
range of perceptibility thresholds. Another commenter said that we
should explain our basis for establishing a threshold of a one-time
impact of greater than 0.5 deciviews, in light of the overall goal of
the regional haze program. Yet another commenter said that the proposal
would ``change the regulatory role of the deciview metric by converting
it into a regulatory 0.5 deciview standard (versus a `goal') for
defining how States must exercise their authority and discretion in
determining whether an individual source `causes or contributes' to
visibility impairment in a Class I area.''
Several commenters said that the 0.5 deciview threshold is too
high. A recurring comment was that the statutory BART applicability
test from CAA Section 169A(b)(2)(A) contains two separate elements:
``causation'' of any visibility impairment and ``contribution'' to any
such impairment. Commenters pointed out that by setting a threshold of
0.5 deciviews, we had combined ``cause or contribute'' into a single
test of causality, thus effectively eliminating the ``contribution''
element of the BART applicability test. The commenters asserted that a
single BART-eligible source can ``contribute'' to visibility impairment
with impacts much lower than 0.5 deciviews. They argued that we must
set the minimum threshold for individual source contribution to
visibility impairment at the lowest level detectable by modeling or
other appropriate analysis, and that this minimum individual
contribution level must in any event be set at no greater than a 0.1
deciview change relative to natural conditions, which is a clearly
measurable level. One commenter suggested that a cause or contribute
threshold be set at some percentage of the ``just noticeable'' change
of 0.5 deciviews.
Another commenter said that in a case where multiple sources each
have a visibility impact of less than a 0.5 deciview change, but
together result in a change of more than 0.5 deciview, each of these
sources contributes to the resulting visibility impairment. This
commenter asserted that BART guidelines that result in exemptions for
these ``contributing'' sources would subvert the goals of the regional
haze program.
Similarly, several commenters suggested that if any combination of
BART eligible sources causes visibility impairment in a Class I area of
more than 0.5 deciviews (by CALPUFF modeling for any 24-hour period,
for example), that State should determine that each individual source
is subject to BART. Thus, the commenter added, the court's concern
about the lack of ``empirical evidence of a source's contribution to
visibility impairment'' would be addressed.
Two commenters said that our requirement to use the maximum 24-hour
value over the 5-year period of meteorological data in the modeling, as
proposed, is too stringent, unreasonable, inappropriate, and departs
from the previous methodologies for the regional haze program.
Additionally they said that the threshold is restrictive because the
single highest 24-hour modeled impact over a three- or five-year period
may be influenced by short-term weather conditions, like high humidity,
and the BART applicability determination should not be made based on a
one-time occurrence.
One commenter said that whatever the final threshold for a single-
source impact for BART sources, EPA should clarify that the purpose of
this modeling assessment is to evaluate a source's anticipated
contribution to uniform regional haze over the Class I area. EPA should
state that the assumption of a uniform haze contribution based on
CALPUFF modeling eliminates the need to assess issues related to the
size of the Class I area, views within a Class I area, and weather
impact interactions. Finally, one commenter said that thresholds should
be established separately for the eastern and western regions of the
United States, as natural visibility conditions are established
separately for eastern and western regions in the guidance.
Final Rule. Today's guidelines advise States to use a deciview
metric in defining ``cause or contribute,'' as explained further below.
The fact that the deciview is also used to track progress toward the
goal of natural visibility does not in any way indicate that we are
``converting'' a ``goal'' into a requirement.\31\ Use of the same
metric in the ``cause or contribute'' context as used for establishing
reasonable progress goals, tracking changes in visibility conditions,
and defining baseline, current, and natural conditions simply provides
for a consistent approach to quantifying visibility impairment.
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\31\ Moreover, the fact that the ultimate purpose of the
visibility provisions is expressed as a ``goal'' does not mean that
all aspects of the program are merely aspirational. CAA section
169A(a)(4) requires EPA to establish regulations to ensure that
reasonable progress is made toward the national visibility goal, and
169A(b)(2) provides that EPA must require SIPs to contain emission
limits, schedules of compliance, and other measures as may be
necessary to make reasonable progress towards meeting the goal.
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In response to commenters who said we conflated the ``cause or
contribute'' test, we are clarifying that for purposes of determining
which sources are subject to BART, States should consider a 1.0
deciview change or more from an individual source to ``cause''
visibility impairment, and a change of 0.5 deciviews to ``contribute''
to impairment.\32\
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\32\ If ``causing'' visibility impairment means causing a
humanly perceptible change in visibility in virtually all situations
(i.e. a 1.0 deciview change), then ``contributing'' to visibility
impairment must mean having some lesser impact on the conditions
affecting visibility that need not rise to the level of human
perception.
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In a regulatory context, we believe that a State's decision as to
an
[[Page 39121]]
appropriate threshold for contribution could depend upon the number of
sources affecting a class I area. To illustrate, if there were only one
emissions source affecting visibility in a class I area, that source
could have a deciview impact only slightly below the perceptibility
threshold without contributing to noticeable impairment. However, if
there were 100 sources each changing visibility by 0.1 deciviews, the
total impact would be a 10-deciview change in visibility. In this
hypothetical example, all 100 sources would be contributing, in equal
amounts, to substantial visibility impairment.
Because circumstances will vary in different locations, we believe
that States should have discretion to set an appropriate threshold
depending on the facts of the situation. We believe, however, that it
would be difficult for a State to justify a threshold higher than 0.5
deciviews. In particular, 0.5 deciviews represents one half of the 1.0
deciview level that we are equating with a single source ``causing''
visibility degradation. Typically, there are multiple sources that
affect visibility in class I areas, so a source causing a 0.5 deciview
change can be expected to be contributing to noticeable visibility
impairment.
In determining whether the maximum threshold of 0.5 deciviews or a
lower threshold is appropriate for purposes of BART, we believe that
States should consider the number of emissions sources affecting the
class I area and the magnitude of the individual sources' impacts.\33\
In general, a larger number of sources causing impacts in a class I
area may warrant a lower contribution threshold. In selecting a
threshold, States may want to take into account the fact that
individual sources have varying amounts of impact on visibility in
class I areas. Depending on the facts regarding the number of sources
affecting a class I area and their modeled impacts, the State could set
a threshold that captures those sources responsible for most of the
total visibility impacts, while still excluding other sources with very
small impacts.\34\
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\33\ All states are working together in regional planning
organizations, and we expect that states will have modeling
information that identifies sources affecting visibility in
individual class I areas, and the magnitude of their impacts.
\34\ Under our guidelines, the contribution threshold should be
used to determine whether an individual source is reasonably
anticipated to contribute to visibility impairment. You should not
aggregate the visibility effects of multiple sources and compare
their collective effects against your contribution threshold because
this would inappropriately create a ``contribution to contribution''
test.
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We also note that under this guidance, States would have discretion
in setting the threshold for ``contributes to'' based on modeled
impacts of sources. Consistent with American Corn Growers, we are not
requiring States to find sources subject to BART regardless of their
impact on Class I areas. We are suggesting that, in establishing a
threshold for assessing contribution for BART, it may be logical to
draw a line between ``contribution'' and ``non-contribution'' based on
the number and magnitude of the various sources affecting the Class I
areas at issue. Such an approach gives States the ability to assess the
empirical evidence showing contribution and to design an appropriate
regulatory regime in light of the nature of the problem. We note that
for 750 MW power plants, such a line drawing exercise is likely to be
unnecessary, as such sources will in most or all cases have impacts far
exceeding 1.0 deciviews.
Finally, we disagree that separate threshold levels should be
established based on geography because a unit change in visibility
expressed in deciviews, perceived or measured, is the same regardless
of geography. As explained in the 1999 regional haze rule, the deciview
can be used to express changes in visibility impairment in a way that
corresponds to human perception in a linear manner. As a result, using
the deciview as the metric for measuring visibility means, for example,
that a one deciview change in a highly impaired environment would be
perceived as roughly the same degree of change as one deciview in a
relatively clear environment, and geography is not a factor.
Interpretation of CALPUFF Results
The standard CALPUFF modeling run provides day-by-day estimates of
a source's visibility effects over a five-year period. In the proposed
BART guideline, we indicated that if the maximum daily visibility value
at any receptor over the five years modeled is greater than the ``cause
or contribute'' threshold, then the State should conclude that the
source is subject to BART. A number of commenters took issue with our
proposal to use the 24-hour maximum modeled visibility impact over five
years of meteorological data. Several of them pointed out, for example,
that the maximum modeled 24-hour impact may be an outlier unduly
influenced by weather. We agree that the maximum modeled effect in a
five-year period could be the result of unusual meteorology. We also
recognize that, although CALPUFF is the best currently available tool
for analyzing the visibility effects of individual sources, it is a
model that includes certain assumptions and uncertainties. Thus, we
agree with commenters that a State should not necessarily rely on the
maximum modeled impact in determining whether a source may reasonably
be anticipated to contribute to visibility impairment in a Class I
area.
The final guideline states that it would be reasonable for States
to compare the 98th percentile of CALPUFF modeling results against the
``contribution'' threshold established by the State for purposes of
determining BART applicability. Some stakeholders have argued for the
90th percentile value, or even lower, contending that EPA should not
use extreme cases to make BART applicability decisions. EPA agrees
that, in most cases, important public policy decisions should not be
based on the extreme tails of a distribution. We have concluded,
however, that the 98th percentile is appropriate in this case.
The use of 90th percentile value would effectively allow visibility
effects that are predicted to occur at the level of the threshold (or
higher) on 36 or 37 days a year. We do not believe that such an
approach would be consistent with the language of the statute. Second,
we note that the 98th percentile value would only be used to determine
whether a particular BART-eligible source would be subject to further
review by the State. In determining what, if any, emission controls
should be required, the State will have the opportunity to consider the
frequency, duration, and intensity of a source's predicted effect on
visibility.
On the other hand, there are other features of our recommended
modeling approach that are likely to overstate the actual visibility
effects of an individual source. Most important, the simplified
chemistry in the model tends to magnify the actual visibility effects
of that source. Because of these features and the uncertainties
associated with the model, we believe it is appropriate to use the 98th
percentile--a more robust approach that does not give undue weight to
the extreme tail of the distribution. The use of the 98th percentile of
modeled visibility values would appear to exclude roughly 7 days per
year from consideration. In our judgment, this approach will
effectively capture the sources that contribute to visibility
impairment in a Class I area, while minimizing the likelihood that the
highest modeled visibility impacts might be caused by unusual
meteorology or conservative assumptions in the model.
[[Page 39122]]
Use of CALPUFF for Visibility Modeling
Background. In providing the States with the option of making a
determination as to which sources are subject to BART based on a
consideration of each source's individual contribution to visibility
impairment, we proposed that States use an air quality model such as
CALPUFF. We also proposed that States use a CALPUFF or other EPA
approved model in the BART analysis itself. The CALPUFF system, as
explained in the 2004 reproposed guideline, consists of a diagnostic
meteorological model, a gaussian puff dispersion model with algorithms
for chemical transformation and complex terrain, and a post processor
for calculating concentration fields and visibility impacts.
The regional haze rule addresses visibility impairment caused by
emissions of fine particles and their precursors. As fine particle
precursors, such as SO2 or NOX, are dispersed,
they react in the atmosphere with other pollutants to form visibility-
impairing pollutants. In fact, Congress implicitly recognized in 1977
the role of chemical transformation in creating visibility impairment,
when it stated that the ``visibility problem is caused primarily by
emissions of SO2, [NOX], and particulate
matter.'' \35\ In most cases, to predict the impacts of a source's
specific contribution to visibility impairment, a State will need a
tool that takes into account not only the transport and diffusion of
directly emitted PM2.5 but also one that can address
chemical transformation.
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\35\ H.R. Rep. No. 95-294 at 204 (1077).
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Because the air quality model CALPUFF is currently the best
application available to predict the impacts of a single source on
visibility in a Class I area, we proposed that a CALPUFF assessment be
used as the preferred approach first, for determining whether an
individual source is subject to BART, and second, in the BART
determination process. The CALPUFF assessment is specific to each
source, taking into account the individual source's emission
characteristics, location, and the particular meteorological,
topographical, and climatological conditions of the area in which the
source is located, any of which may have an impact on the transport of
PM2.5 and its precursors. CALPUFF can be used to estimate
not only the effects of directly emitted PM2.5 emissions
from a source, but also to predict the visibility impacts from the
transport and chemical transformation of fine particle precursors.
The CALPUFF model is generally intended for use on scales from 50
km to several hundred kilometers from a source. As a general matter,
States will typically need to assess the impacts of potential BART
sources on Class I areas located more than 50 km from the source.\36\
However, in situations where the State is assessing visibility impacts
for source-receptor distances less than 50 km, we proposed that States
use their discretion in determining visibility impacts, giving
consideration to both CALPUFF and other EPA-approved methods. As an
example, we suggested that States could use an appropriate local-scale
plume impact model, such as PLUVUEII,\37\ to determine whether a
source's emissions are below a level that would be reasonably
anticipated to cause or contribute to visibility impairment in any
Class I area.
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\36\ To determine whether a BART-eligible source ``may
reasonably be anticipated to cause or contribute to any visibility
impairment in any Class I area,'' it may not always be sufficient
for the State to predict the impacts of a BART-eligible source only
on the nearest Class I area (or on the nearest receptor in the
nearest Class I area). The particular meteorological and
topographical conditions, for example, could mean that a source's
greatest impacts occurred at a Class I area other than the nearest
one.
\37\ PLUVUEII is a model used for estimating visual range
reduction and atmospheric discoloration caused by plumes resulting
from the emissions of particles, nitrogen oxides, and sulfur oxides
from a single source. The model predicts the transport, dispersion,
chemical reactions, optical effects and surface deposition of point
or area source emissions. It is available at http://www.epa.gov/scram001/tt22.htm#pluvue.
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Comments. A number of States, environmental groups, and some
industry commenters strongly supported the use of CALPUFF as proposed.
Many commenters supported the use of CALPUFF but indicated that States
must have the flexibility to use additional tools for their individual
source analyses. Some suggested options for the ``cause or contribute''
determination were the use of photochemical grid models, or more
simplified, non-modeling approaches. Commenters claimed that States
must have the option to incorporate advances in science and
technologies into models or other applications that may produce more
accurate simulations of meteorology, chemistry, and visibility
impairment. Other industry groups and States argued that CALPUFF has
significant limitations, especially simulating complex atmospheric
chemistry, and that EPA's recommendation of CALPUFF as the preferred
approach is therefore inappropriate.
Another issue raised by commenters was the use of CALPUFF for
estimating secondary particulate matter formation. Commenters
recognized that CALPUFF was incorporated into the ``Guideline on Air
Quality Models'' at 40 CFR part 51, appendix W in April 2003 as the
preferred model for Prevention of Significant Deterioration (PSD)
increment and National Ambient Air Quality Standards (NAAQS) compliance
assessments of long range transport of primary emissions of
SO2 and PM2.5. However, commenters stated that
CALPUFF has not been incorporated into the Guideline on Air Quality
Models for predicting the secondary formation of PM. The commenters
remarked that EPA guidance indicates that photochemical grid models be
used to simulate secondary PM formation and concluded on this basis
that the application of CALPUFF as we proposed is in conflict with our
guidance.
Final rule. We believe that CALPUFF is an appropriate application
for States to use for the particular purposes of this rule, to
determine if an individual source is reasonably anticipated to cause or
contribute to impairment of visibility in Class I areas, and to predict
the degree of visibility improvement which could reasonably be
anticipated to result from the use of retrofit technology at an
individual source. We encourage States to use it for these
purposes.\38\
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\38\ The model code and its documentation are available at no
cost for download from http://www.epa.gov/scram001/tt22.htm#calpuff.
---------------------------------------------------------------------------
CALPUFF is the best modeling application available for predicting a
single source's contribution to visibility impairment. It is the only
EPA-approved model for use in estimating single source pollutant
concentrations resulting from the long range transport of primary
pollutants. In addition, it can also be used for some purposes, such as
the visibility assessments addressed in today's rule, to account for
the chemical transformation of SO2 and NOX. As
explained above, simulating the effect of precursor pollutant emissions
on PM2.5 concentrations requires air quality modeling that
not only addresses transport and diffusion, but also chemical
transformations. CALPUFF incorporates algorithms for predicting both.
At a minimum, CALPUFF can be used to estimate the relative impacts of
BART-eligible sources. We are confident that CALPUFF distinguishes,
comparatively, the relative contributions from sources such that the
differences in source configurations, sizes, emission rates, and
visibility impacts are well-reflected in the model results. States can
make judgements
[[Page 39123]]
concerning the conservativeness or overestimation, if any, of the
results. In fact, although we focused on the use of CALPUFF for primary
pollutants in revising the Guideline of Air Quality Modeling, section
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7.2.1.e. of the Guideline states:
e. CALPUFF (Section A.3) may be applied when assessment is
needed of reasonably attributable haze impairment or atmospheric
deposition due to one or a small group of sources. This situation
may involve more sources and larger modeling domains than that to
which VISCREEN ideally may be applied. The procedures and analyses
should be determined in consultation with the appropriate reviewing
authority (paragraph 3.0(b) and the affected FLM(s).
We believe that our proposed use of CALPUFF is thus fully in
keeping with the Guideline on Air Quality Models, especially in light
of the low triggering threshold for determining whether a source is
reasonably anticipated to cause or contribute to visibility impairment
in a Class I area, and the fact that the modeling results are used as
only one of five statutory criteria evaluated to determine BART
emission limits.
Even so, as commenters point out, CALPUFF has not yet been fully
evaluated for secondary pollutant formation. For the specific purposes
of the regional haze rule's BART provisions, however, we have concluded
that CALPUFF is sufficiently reliable to inform the decision making
process.
EPA revised the Guideline on Air Quality Models in 2003, in part,
to add CALPUFF to the list of approved models for particular uses. At
that time, we considered comments that CALPUFF should be approved for
use in predicting the impact of secondary emissions on particulate
matter concentrations. As we stated in the revision, CALPUFF represents
a substantial improvement in methods for assessing long-range transport
of air pollutants. However, as explained in the response to comments
for that rulemaking, the modeling results in the context of a PSD
review may be used as the sole determining factor in denying a source a
permit to construct.\39\ Although its use in simulating long-range
transport is beneficial, given the significance of the modeling results
in assessing increment consumption due to a single source's impacts, we
made a determination that it would not be appropriate in the rulemaking
revising Appendix W to approve CALPUFF for use in modeling secondary
emissions.
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\39\ Under CAA section 165(a), a major emitting facility may not
be constructed unless the owner or operator of the facility
demonstrates that the emissions from the facility will not cause or
contribute air pollution in excess of an increment or NAAQS.
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In contrast to the significance of the modeling results in the PSD
context, the use of CALPUFF in the context of the regional haze rule is
not determinative of a source's ability to construct or operate. A
State may use CALPUFF to determine whether a source can reasonably be
anticipated to cause or contribute to visibility impairment and so
should be subject to additional review to determine if the source
should be subject to control.
Based on our analysis of the power plants covered by the
guidelines, we believe that all but a handful of these plants have
impacts of greater than 1.0 deciview on one or more Class I areas.\40\
In fact, we anticipate that most of these plants are predicted to have
much higher maximum impacts.\41\ Because of the scale of the predicted
impacts from these sources, CALPUFF is an appropriate or a reasonable
application to determine whether such a facility can reasonably be
anticipated to cause or contribute to any impairment of visibility. In
other words, to find that a source with a predicted maximum impact
greater than 2 or 3 deciviews meets the contribution threshold adopted
by the States does not require the degree of certainty in the results
of the model that might be required for other regulatory purposes.
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\40\ CALPUFF Analysis in Support of the Regional Haze Rule, U.S.
Environmental Protection Agency, April 15, 2005, Docket No. OAR-
2002-0076.
\41\ Ibid.
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In the unlikely case that a State were to find that a 750 MW power
plant's predicted contribution to visibility impairment is within a
very narrow range between exemption from or being subject to BART, the
State can work with EPA and the FLM to evaluate the CALPUFF results in
combination with information derived from other appropriate techniques
for estimating visibility impacts to inform the BART applicability
determination. Similarly for other types of BART eligible sources,
States can work with the EPA and FLM to determine appropriate methods
for assessing a single source's impacts on visibility.
As discussed in section E. below we also recommend that the States
use CALPUFF as a screening application in estimating the degree of
visibility improvement that may reasonably be expected from controlling
a single source in order to inform the BART determination. As we noted
in 2004, this estimate of visibility improvement does not by itself
dictate the level of control a State would impose on a source; ``the
degree of improvement in visibility which may reasonably be anticipated
to result from the use of [BART]'' is only one of five criteria that
the State must consider together in making a BART determination. The
State makes a BART determination based on the estimates available for
each criterion, and as the CAA does not specify how the State should
take these factors into account, the States are free to determine the
weight and significance to be assigned to each factor. CALPUFF
accordingly is an appropriate application for use in combination with
an analysis of the other statutory factors, to inform decisions related
to BART.
We understand the concerns of commenters that the chemistry modules
of the CALPUFF model are less advanced than some of the more recent
atmospheric chemistry simulations. To date, no other modeling
applications with updated chemistry have been approved by EPA to
estimate single source pollutant concentrations from long range
transport. In its next review of the Guideline on Air Quality Models,
EPA will evaluate these and other newer approaches and determine
whether they are sufficiently documented, technically valid, and
reliable to approve for general use. In the meantime, as the Guideline
makes clear, States are free to make their own judgements about which
of these or other alternative approaches are valid and appropriate for
their intended applications.
Theoretically, the CALPUFF chemistry simulations, in total, may
lead to model predictions that are generally overestimated at distances
downwind of 200 km. Again, States can make judgements concerning the
conservativeness or overestimation, if any, of the results.
The use of other models and techniques to estimate if a source
causes or contributes to visibility impairment may be considered by the
State, and the BART guidelines preserve a State's ability to use other
models. Regional scale photochemical grid models may have merit, but
such models have been designed to assess cumulative impacts, not
impacts from individual sources. Such models are very resource
intensive and time consuming relative to CALPUFF, but States may
consider their use for SIP development in the future as they are
adapted and demonstrated to be appropriate for single source
applications. However, to date, regional models have not been evaluated
for single source applications. Their use may be more appropriate in
the cumulative modeling options discussed
[[Page 39124]]
above.\42\ In evaluating visibility improvement as one of the five
factors to consider in setting BART controls, other models, used in
combination with CALPUFF may be helpful in providing a relative sense
of the source's visibility impact and can aid in informing the BART
decision. A discussion of the use of alternative models is given in the
Guideline on Air Quality in appendix W, section 3.2.
---------------------------------------------------------------------------
\42\ For regional haze applications, regional scale modeling
typically involves use of a photochemical grid model that is capable
of simulating aerosol chemistry, transport, and deposition of
airborne pollutants, including particulate matter and ozone.
Regional scale air quality models are generally applied for
geographic scales ranging from a multi-state to the continental
scale. Because of the design and intended applications of grid
models, they may not be appropriate for BART assessments, so States
should consult with the appropriate EPA Regional Office prior to
carrying out any such modeling.
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The Use of Natural Conditions in Determining Visibility Impacts for
Reasonable Progress and Comparison to Threshold Values
Background. As set out in section 169A(a) of the CAA and stated in
the 1999 regional haze rule, a return to natural visibility conditions,
or the visibility conditions that would be experienced in the absence
of human-caused impairment, is the ultimate goal of the regional haze
program. To measure progress toward this goal, the regional haze rule
requires that a comparison with natural conditions for the 20 percent
best and worst days to calculate ``reasonable progress''
determinations. Default values for natural visibility conditions are
provided in EPA guidance.\43\ In the 2004 reproposal of the BART
guidelines, we proposed that changes in visibility, expressed in
deciviews, should be determined by comparing the impact from a single
source to natural visibility conditions. That impact should then be
compared to a threshold impact, also expressed in deciviews, to assess
if a BART-eligible source should be subject to a BART review.
---------------------------------------------------------------------------
\43\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, U.S. Environmental Protection Agency,
September 2003. http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf. Natural background conditions, expressed in
deciviews, are defined for each Class I area. EPA has issued
guidance for estimating natural background conditions which has
estimates of default conditions as well as measures to develop
refined estimates of natural conditions.
---------------------------------------------------------------------------
Comments. Opposing commenters said that a return to natural
conditions is unattainable as it would require the elimination of every
manmade source, and that changes should be compared against currently
existing conditions. They added that true ``natural conditions'' cannot
be verified, do not account for manmade emissions from other countries,
and are not a realistic target for improvement. Further, they argued
that natural conditions are a ``goal'' representing a benchmark that is
relevant to the States' determination, under the regional haze program,
of the level of ``reasonable progress'' to achieve; however they stated
that there is no legal requirement (and there could not be a legal
requirement) that the natural conditions goal ultimately must be
achieved. Several commenters added that current visibility conditions
make more sense as a baseline because sources that are subject to BART
today will likely not be in operation in the 2064 time frame. A
commenter added that using current visibility conditions for the
analysis will give a more realistic, real-world prediction of whether
controlling the source pursuant to BART will actually improve
visibility. The commenter said that Congress did not intend for sources
to have to consider retrofitting controls under the BART provision if
those sources currently are not impacting real-world visibility. Other
utility groups stated that in addition to international emissions, the
estimated natural visibility conditions failed to account for natural
phenomena such as sea salt, wildfires, and natural organics. One
commenter noted that natural visibility estimates will be revised and
refined over time and it would be unwise to compare impacts and
improvements to a moving baseline.
On the other hand, numerous commenters supported the use of natural
visibility conditions as a baseline for measuring visibility
improvements. Several environmental groups said that any increase in
the baseline beyond natural visibility conditions will unlawfully
distort and weaken the BART requirement by effectively raising the
applicability threshold in less protected, highly polluted areas, which
would be illogical. Further, they pointed out that these BART-eligible
sources clearly are contributing to the very manmade visibility
impairment that the Act is explicitly designed to remedy by a return to
natural conditions. They added that measuring natural conditions as
opposed to some other baseline condition is a more appropriate
approach, given that the planning goal is to achieve natural visibility
by the end of the program. They also added that a baseline other than
natural conditions would never assure ``reasonable progress''.
Finally, two commenters asked for clarification on the values for
natural conditions to be used for estimating changes in visibility. The
commenters appeared to assume that we intended for the comparison to be
done for natural visibility conditions on the 20 percent best days.
Final Rule. We disagree with commenters saying that the use of
natural conditions as the baseline for making visibility impact
determinations is inappropriate. The visibility goal of the CAA is both
the remedying of existing impairment, and prevention of future
impairment. The court, in American Corn Growers, upheld our
interpretation of that goal as the return to natural visibility
conditions.\44\ Long-term regional haze strategies are developed to
make ``reasonable progress'' towards the CAA goal, and States must
demonstrate reasonable progress in their regional haze State
implementation plans (SIPs). Since the BART program is one component of
that demonstration, visibility changes due to BART are appropriately
measured against the target of natural conditions.
---------------------------------------------------------------------------
\44\ See also our explanation of the CAA goal provided in the
regional haze rule at 64 FR at 35720-35722. We note that the court
in American Corn Growers also observed, ``the natural visibility
goal is not a mandate, it is a goal.'' 291 F.3d at 27.
---------------------------------------------------------------------------
In establishing the goal of natural conditions, Congress made BART
applicable to sources which ``may be reasonably anticipated to cause or
contribute to any impairment of visibility at any Class I area''. Using
existing conditions as the baseline for single source visibility impact
determinations would create the following paradox: the dirtier the
existing air, the less likely it would be that any control is required.
This is true because of the nonlinear nature of visibility impairment.
In other words, as a Class I area becomes more polluted, any individual
source's contribution to changes in impairment becomes geometrically
less. Therefore the more polluted the Class I area would become, the
less control would seem to be needed from an individual source. We
agree that this kind of calculation would essentially raise the ``cause
or contribute'' applicability threshold to a level that would never
allow enough emission control to significantly improve visibility. Such
a reading would render the visibility provisions meaningless, as EPA
and the States would be prevented from assuring ``reasonable progress''
and fulfilling the statutorily-defined goals of the visibility program.
Conversely, measuring improvement against clean conditions would ensure
reasonable progress toward those clean conditions.
[[Page 39125]]
With regard to BART-eligible sources not being in operation for the
duration of the program, a State, in making BART determinations, is
explicitly directed by the CAA to account for the remaining useful life
of a source. Thus, States may factor into their reasonable progress
estimates those shut-downs that are required and effected in permit or
SIP provisions. In addition, as provided for under our guidance,\45\
proper accounting for international emissions and natural phenomena is
in the 5 year SIP progress report, not in the setting of natural
visibility estimates. Finally, these final BART guidelines use the
natural visibility baseline for the 20 percent best visibility days for
comparison to the ``cause or contribute'' applicability thresholds. We
believe this estimated baseline is likely to be reasonably conservative
and consistent with the goal of natural conditions.
---------------------------------------------------------------------------
\45\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, U.S. Environmental Protection Agency,
September 2003. http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf.
---------------------------------------------------------------------------
Modeling Protocol
Background. The 2004 guidelines proposed that a written modeling
protocol be submitted for assessing visibility impacts from sources at
distances greater than 200 km from a Class I area. The proposal
indicated that the protocol should include a description of the methods
and procedures to follow, for approval by the appropriate reviewing
authority; critical items to include in the protocol are meteorological
and terrain data, source-specific information (stack height,
temperature, exit velocity, elevation, and allowable emission rate of
applicable pollutants), and receptor data from appropriate Class I
areas.
Comments. All of the comments supported the development of a
written modeling protocol. Industry, Federal, and State commenters said
a modeling protocol should be required of all States and stakeholders
who are performing the BART modeling analysis. Commenters said the
protocol should allow all interested parties an opportunity to
understand the modeling approach and how the results will be used, and
that the State should provide opportunity for comments on the
procedures prior to the publication of the final results.
Many utility groups commented that the protocol should provide
States with flexibility and that the choice of models should be at the
States' (or RPOs') discretion. Some commenters stressed that it is
important that states and sources retain the flexibility to decide how
to set up and run the selected model, while others asked for specific
guidance on the setup of CALPUFF or other approved models, including on
specific parameters (e.g. how to adjust for cases where sources are
greater than 200 km from a Class I area).
Regarding the approval of a modeling protocol, some commenters said
that the protocol should be approved by EPA. Others stated, however,
that we should have only an advisory role in development of the
protocol. They said that States are in a better position to determine
which modeling input values best reflect conditions in their States.
Several commenters representing environmental groups said we should
develop a CALPUFF protocol that must be followed and should include,
among other items, meteorological data (i.e., where available 5 years
of data should be used), emissions reported for the same meteorological
years, documented source parameters, model physical parameters, and
assumed background concentrations for ozone and ammonia (based on
nearby reliable observations and/or regional modeling results). They
added that a protocol developed by EPA would help to produce consistent
BART determinations across various sources and geographic areas for
both shorter and longer distances. FLMs stated that this is also an
appropriate time to create regional modeling platforms for CALPUFF,
which would allow States and sources to run the model more
expeditiously and more consistently. They recommended that we consider
a multi-agency process to reach agreement on an appropriate modeling
protocol prior to allowing BART applicability and control
determinations to be based on model results. FLMs added that it would
be helpful to establish a national procedure for this process,
including a methodology for establishing natural background conditions,
background ammonia concentrations, and determining sulfuric acid
emission rates. Such a process, they said, could reasonably be engaged
in prior to deadlines for state implementation plans, and would not
delay implementation of the BART guidelines. The FLMs noted that
consistent, nationally applicable guidance is essential, and that once
it is developed, virtually no deviations should be allowed. Finally,
they added that the CALPUFF modeling exercises should follow the
Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary
Report and Recommendations for Modeling Long Range Transport
Impacts,\46\ but that we, in consultation with the FLMs and States,
should also publish additional guidance to address more recent issues
such as particle speciation, emission rate averaging times, and
``natural obscuration.'' Another State commenter said that The
Guideline on Air Quality Models (CFR Part 51, Appendix W) should be
included along with the IWAQM Report as a reference for CALPUFF setup.
One RPO commented that we should provide data, perhaps using example
facilities, to demonstrate the effect of the process so that States can
get a better feeling for which sources are likely to fall below the 0.5
deciview threshold. This would help States understand the net effect of
all of the parameters chosen in the exemption process.
---------------------------------------------------------------------------
\46\ Interagency Workgroup on Air Quality Modeling (IWAQM) Phase
2 Summary Report and Recommendations for Modeling Long Range
Transport Impacts, U.S. Environmental Protection Agency, EPA-454/R-
98-019, December 1998.
---------------------------------------------------------------------------
Commenters also said that we should continuously revise modeling
protocols by providing a modeling clearinghouse to States, and further,
that we should consider new models for use, such as the Community
Multiscale Air Quality (CMAQ) model.
There were specific comments requesting guidance for calculating
visibility impacts and other general modeling concerns. One technical
comment was that the guidelines should specify that the IMPROVE monitor
is the receptor by which modeled visibility impacts should be evaluated
with the CALPUFF model. Another commenter suggested using recent
scientific evidence to update the light extinction coefficients used by
CALPUFF to calculate visibility changes. These commenters also stated
that CALPUFF might be improved by capping the relative humidity to
lower values than are currently used.
Additional commenters representing utility organizations discussed
how to identify Class I areas that should be modeled. They said that
the guidelines should require sources to model only the nearest Class I
area (or possibly the two closest), and one commenter said that we
should provide a reasonable methodology to minimize the effort needed
to address impacts from BART-eligible sources on multiple Class I
areas.
Final Rule. We agree that States should adopt modeling protocols
for all modeling demonstrations, regardless of the distance from the
BART-eligible source and the Class I area impacted. We are therefore
dropping the 200 km and greater distance requirement from the
guidelines. As noted in the 2004 re-
[[Page 39126]]
proposal, we believe that potential uncertainties in model performance
may be greater at distances greater than 200 km for a source. A
modeling protocol may reduce the need for additional analyses. We favor
coordination among States, EPA regions, RPOs, and other federal
agencies to agree on a modeling protocol(s) which would provide
consistent application.
In developing a modeling protocol, we also encourage States to use
the framework provided for model setup in EPA's IWAQM. CALPUFF model
users may find default settings in that document which may be
appropriate for their modeling situations and add an element of
consistency to model applications. The Guideline on Air Quality Models
(CFR Part 51, Appendix W) also provides useful guidance.
We do, however, understand and agree that States have flexibility
developing a modeling protocol. Moreover, the diversity of the nation's
topography and climate, and variations in source configurations and
operating characteristics, dictate against a strict modeling
``cookbook''. A State may need to address site-specific circumstances
at individual sources potentially affecting a specific Class I area.
For example, in a particular area a State may have available emissions
data, that is more representative of the modeling domain, which may
supplement the model defaults. States may want to consult with the
appropriate EPA regional office and Federal Land Managers in adjusting
the model input parameters. The modeling input recommendations in the
IWAQM report are designed for visibility impact applications, and those
defaults allow for tailoring for a given application (e.g. puff
splitting). The model developers Web site \47\ also has a series of
frequently asked questions with answers to assist users in tailoring
model applications.
---------------------------------------------------------------------------
\47\ http://www.src.com/calpuff/calpuff1.htm.
---------------------------------------------------------------------------
We agree that we have only an advisory role in development of the
protocol as the States better understand the BART-eligible source
configurations and the geophysical and meteorological data affecting
their particular Class I area(s).
In the protocol development process, we support the idea of
designing example runs, as we have done in our example analysis for
EGUs,\48\ so that States may get a better understanding of what
visibility impacts might be expected from a particular type of source
or sources. Once a protocol has been finalized, a State may be able to
use example runs as a proxy in making BART determinations which could
potentially eliminate the need for case-by-case review for every BART-
eligible source. A common sense approach should be taken, particularly
where an analysis may add a significant resource burden to a State. For
example, if there are multiple Class I areas in relatively close
proximity to a BART-eligible source, a State may model a full field of
receptors at the closest Class I area. Then a few strategic receptors
may be added at the other Class I areas (perhaps at the closest point
to the source, a receptor at the highest and lowest elevation in the
Class I area, a receptor at the IMPROVE monitor, and a few receptors
that are expected to be at the approximate plume release height). If
the highest modeled impacts are observed at the nearest Class I area, a
State may choose not to analyze the other Class I areas any further and
additional analyses might be unwarranted.
---------------------------------------------------------------------------
\48\ CALPUFF Analysis in Support of the June 2005 Changes to the
Regional Haze Rule,U.S. Environmental Protection Agency, June 15,
2005, Docket No. OAR-2002-0076.
---------------------------------------------------------------------------
As models are revised and advances in science are incorporated into
the models, we can make certain that revisions to protocols are made
accordingly. We will work closely with States and FLMs, as should
States; we expect that States will also work closely with FLMs
throughout the protocol development process. We expect a similar
protocol development process for other models that may be used, once
those models are developed to predict and track single source impacts
and demonstrate acceptable model performance. States should contact the
appropriate FLM and EPA regional office for the latest guidance and
modeling updates.
Alternatives for Determining Visibility Impacts From Individual Sources
Background. In the 2004 reproposal, we requested comment on the
following alternatives to CALPUFF modeling for determining whether
individual sources cause or contribute to visibility impairment: look-
up tables developed from screening-level air quality modeling; running
CALPUFF in a simpler screening mode than the preferred approach; a
source ranking methodology; and an emissions divided by distance (Q/D)
method. Except for the simplified CALPUFF approach, all alternatives
were based on developing a relationship between source emissions and
the source's distance to a Class I area. Each of these approaches was
intended to reduce the resource burden on States.
Comments. Some commenters supported the use of alternative
approaches, while others suggested that the alternatives could be used
either in conjunction, or in hierarchical fashion, with modeling
approaches. Many commenters were opposed to their use. The opposing
comments were consistent in stating that the alternatives were
inappropriate because they did not account for important factors such
as terrain, local meteorological data, prevailing wind directions
(which influence pollutant transport), and differences in stack release
parameters. Commenters added that there is no direct connection between
emissions, distance, and visibility impairment, and that the methods
treat SO2 and NOX equally for impairment
estimates.
Final Rule. We disagree that the alternatives are necessarily
inappropriate, but we share most of the concerns articulated by the
opposing commenters. We believe that alternatives should not be used to
exempt a source from BART review without more rigorous evaluations and
sensitivity tests showing that the results are at least as conservative
as the CALPUFF model. We know of at least one study showing that, for
one location and for one year, there is no guarantee that the
simplified CALPUFF technique is as conservative as the preferred
approach \49\. While we are not adopting in the guideline any specific
alternative to modeling for power plants greater than 750MW, a State
may develop its own alternative approach for the other source
categories to determine if a source would be subject to BART, provided
that the alternative demonstrates a sufficient basis to determine
clearly that the source causes or contributes to visibility impairment,
or that more refined analysis is warranted. Use of an alternative
approach could be a conservative non-modeling method for easing a
State's resource burden. We believe conservatism is needed because of
the purpose of the test: i.e. solely to determine if a closer look at
the source is warranted.
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\49\ Analysis of the CALMET/CALPUFF Modeling System in a
Screening Mode, U.S. Environmental Protection Agency, November 1998,
Docket No. OAR-2002-0076.
---------------------------------------------------------------------------
E. The BART Determination Process
Background. CAA section 169A(g)(7) directs States to consider five
factors in making BART determinations. The regional haze rule codified
these factors in 40 CFR 51.308(e)(1)(ii)(B), which directs States to
identify the ``best system of continuous emissions control
[[Page 39127]]
technology'' taking into account ``the technology available, the costs
of compliance, the energy and nonair quality environmental impacts of
compliance, any pollution control equipment in use at the source, and
the remaining useful life of the source.'' Section IV. of the BART
guidelines provides a step-by-step guide to conducting a BART
determination which takes these factors into account.
This section of the preamble addresses a number of issues relative
to the process for conducting a BART determination contained in Section
IV of the BART guidelines.
1. What Is Meant by ``Technical Feasibility of the Control Options'' in
Step 2 of the BART Determination?
Comments. We received several comments on this discussion, both on
the 2001 proposal and on the 2004 reproposal. One commenter recommended
that the concept of available technology for regional haze should be
expanded to include those in the pilot scale testing phase, because
these guidelines will precede the installation of controls by about 10
years. Other commenters believed that the discussion of technical
feasibility introduced terms and concepts that were not clear, for
example, what is meant by ``commercial demonstration.'' One commenter
raised issues with deeming technologies used in foreign countries
``available'' unless their performance has been demonstrated in the
United States. A few commenters expressed concern with the provision in
the guidelines that new technologies should be considered up to the
time of a State's public comment period on the BART determination. The
commenter believed that this could create an endless review loop for
States if new technologies continually became available.
Final rule. In the final guidelines, we have largely retained the
language that was in the proposed guidelines. Because the guidelines
call for consideration of technologies that become available by the
time of the State's public comment process on the BART determination,
technologies should be considered that become available well after we
finalize the BART guidelines. We also note, for clarity, that the
Guidelines state that technologies need to be both licensed and
commercially available (i.e. commercially demonstrated and sold).
2. How Should the Costs of Control Be Estimated in Step 4 of the BART
Determination?
Comments. This section of the guidelines remained unchanged between
the 2001 proposal and the 2004 reproposal. Comments varied, ranging
from questioning the reliance on EPA's OAQPS Control Cost Manual Fifth
Edition, February 1996, EPA 453/B-96-001 (hereafter called the
``Control Cost Manual'') to requesting that we not include the concept
of incremental cost effectiveness in the guidelines. A commenter
expressed concerns that incremental cost effectiveness calculations,
the cost of implementing each succeeding control option, is too
dependent on the number of interim options included in the analysis.
Moreover, the commenter believed that incremental cost calculations
increase the complexity of the analysis, and they also increase the
possibility for inconsistent cost results.
Final rule. We have finalized this section of the guidelines with
some changes to how it was proposed. States have flexibility in how
they caculate costs. We believe that the Control Cost Manual provides a
good reference tool for cost calculations, but if there are elements or
sources that are not addressed by the Control Cost Manual or there are
additional cost methods that could be used, we believe that these could
serve as useful supplemental information.
In addition, the guidelines continue to include both average and
incremental costs. We continue to believe that both average and
incremental costs provide information useful for making control
determinations. However, we believe that these techniques should not be
misused. For example, a source may be faced with a choice between two
available control devices, control A and control B, where control B
achieves slightly greater emission reductions. The average cost (total
annual cost/total annual emission reductions) for each may be deemed to
be reasonable. However, the incremental cost (total annual
costA-B/total annual emission reductionsA-B) of
the additional emission reductions to be achieved by control B may be
very great. In such an instance, it may be inappropriate to choose
control B, based on its high incremental costs, even though its average
cost may be considered reasonable.
Finally, it is important to note that, while BART determinations
are focused at individual sources, it is likely that in response to SIP
requirements, States will be making BART determinations for many units
in a subject source category all at the same time. In doing so, States
are likely to compare costs across each source category as well as
looking at costs for individual units in order to respond to SIP
requirements in an efficient manner (from the State's perspective).
3. How Should ``Remaining Useful Life'' Be Considered in Step 4 of the
BART Determination?
Comments. We received a number of comments on the issue of
remaining useful life, both on the 2001 proposal and on the 2004
reproposal. One commenter asserted that remaining useful life should
not be considered in the cost analysis and that if a source is in
operation at the time of a State's SIP submittal, it must have plans to
install controls. Other commenters believed that, to the extent that
assertions regarding a plant's remaining useful life influences the
BART decision, there must be an enforceable requirement for the plant
to shut down by that date. Other comments questioned whether Congress
intended enforceable restrictions in order to take into account the
remaining useful life and whether EPA had the authority under the CAA
to require plant shutdowns.
A number of comments were received regarding our request for
comments on how to provide flexibility for situations where market
conditions change. Some comments interpreted this provision as a
loophole that would allow sources to continue operation for a number of
years without BART. Another comment supported the concept of allowing a
source to later change its mind, so long as BART is installed.
Final rule. We have retained the approach in the proposed
guidelines, including the provision for flexibility for sources to
continue operating, with BART in place, should conditions change. We
believe that the CAA mandates consideration of the remaining useful
life as a separate factor, and that it is appropriate to consider in
the analysis the effects of remaining useful life on costs. We believe
that, because the source would not be allowed to operate after the 5-
year point without such controls, the option for providing flexibility
would not create a loophole for sources. Moreover, any source operating
after this point without BART controls in place would be subject to
enforcement actions for violating the BART limit. For any source that
does not agree to shut down before the 5-year point, the State should
identify a specific BART emission limit that would apply after this
point in time.
4. How Should ``Visibility Impacts'' Be Considered in Step 5 of the
BART Determination?
Background. The fifth statutory factor addresses the degree of
improvement in
[[Page 39128]]
visibility which may reasonably be anticipated to result from the use
of the ``best control technology'' for sources subject to BART. The
2004 reproposal focuses on the use of single source emissions modeling
to evaluate the BART control options. As part of the BART
determination, we proposed that a State or individual source would run
CALPUFF, or another EPA-approved model, to estimate, in deciviews, a
BART source's visibility impact at a Class I area. The source would run
the model once using its allowable emission rates, and then again at
the various post-control emissions rates being evaluated for the BART
determination. The 24-hour model results would then be tabulated for
the pre- and post-control scenarios, for the average of the 20 percent
worst modeled days at each receptor, over the time period of
meteorology modeled. The difference in the averages for each receptor
is the expected degree of improvement in visibility. Alternatively, the
proposal requested comment on the option of using the hourly modeled
impacts from CALPUFF at each receptor and determining the improvement
in visibility based on the number of hours above the 0.5 deciview
threshold for both the pre- and post-control model runs. We also
requested comment on combinations of the proposed and alternative
options and on the use of the simpler screening version of CALPUFF to
do the analysis.
Comments. Several environmental groups said that issues relating to
the determination of visibility improvement for evaluating BART
controls are in many ways the same as for determining which BART-
eligible sources are subject to BART. Thus, the commenter pointed out,
the issues concerning the BART applicability test, discussed in section
D., are all equally applicable here, including comments on: using the
0.5 deciview threshold on an aggregate basis for determining visibility
impairment and potential exemption for BART-eligible sources, use of a
natural visibility baseline versus current visibility, using a
substantially lower deciview threshold than 0.5 deciviews to determine
the contribution to visibility impairment by an individual source, and
demonstration of those thresholds by means of appropriate modeling
rather than other less reliable and more subjective techniques.
An industry commenter claimed that the American Corn Growers case
emphasized the fact that the CAA clearly provides that BART
determinations should balance the visibility benefits of controls
comprehensively against their burdens; the commenter noted that this is
not mentioned in our proposal; the commenter said that although the
proposal would allow States to run the CALPUFF model, it fails to
specify how they might consider the results.
One State commenter opposed the use of visibility modeling for the
purpose of informing the choice of control option, stating that it is
unnecessary, confusing and without adequate standards or guidance for
implementation. The State added that the analysis of control options in
the BART process should yield the greatest, most cost-effective control
efficiency for NOX and SO2 at or above our
presumptive levels of control. Moreover, it said that analysis of the
degree of visibility improvement may result in very small increments of
visibility improvements within Class I areas from an individual source,
thus tilting the selection to the lower control efficiency option. The
State added that we should remove this criterion from the analysis to
ensure that the best cost effective controls will result. Another State
agency said that modeling impacts should not be considered in BART
determinations because they are not considered when determining BACT
for the PSD program.
A variety of commenters pointed out several areas where the
guidelines should be improved or clarified in regard to the degree of
visibility improvement determination:
We should clarify that the analysis is pollutant-specific
(e.g., the modeling evaluation of a BART control option for
SO2 reduction should not be combined with the modeling
evaluation of a BART control option for NOX.)
We should clarify that only the closest Class I area must
be modeled.
We should describe CALPUFF as one possible model to use,
rather than as the only model that may be used.
States and sources should have the flexibility to perform
multiple modeling runs based on different levels of available control.
Predicted visibility improvements that are imperceptible
should be given no weight in determining the level of control that
constitutes BART.
States should be allowed to establish a factor for the
required degree of visibility improvement.
Several industry and utility commenters expressed concern about
using allowable emission rates to predict visibility impacts for BART
control options; they argued that actual emission rates should be
considered instead. Three commenters stated that we must make clear
that States should use emission rates that will be permissible at the
time BART controls take effect, not current emissions rates.
Additional comments from utilities, industry, and one State opposed
the approach wherein the results from the 20 percent worst modeled days
(pre- and post-control) were used to evaluate the visibility
improvements expected from the various control options. Some believed
this was too stringent, while others said it was not stringent enough.
Two utilities added that the criteria should use the 20 percent worst
days based on monitored data, not modeled data. An environmental group
stated that sources should not be limited to just the worst days, but
the improvements should be based upon controls reducing visibility
impairment on any day. The commenter added that this rationale ignores
the middle 60 percent of days in which visibility may worsen, because
sources may increase emissions on these days as a trade-off for cutting
emissions on the worst days. The commenter further argued that there
are no data to support our assertion that improvement on the worst days
means improvement on other days. They noted that default ``natural
condition'' deciview values for Class I areas in our natural conditions
guidance exist only for the average of the 20 percent best and worst
days. The commenter added that we used the average default natural
conditions (for the 20 percent best days) for the visibility impairment
analysis, but there are no default ``maximum 24-hour'' values in the
guidance.
Nine commenters supported implementation of visibility improvement
thresholds, which were not proposed in 2004. A State commenter said it
is unclear how the modeled net visibility improvement would be
specifically utilized in the BART analysis, and requested a target
level of improvement or a de minimis level by which to measure
improvement. Two industry commenters suggested alternatives to the 24-
hour value. One said that setting a threshold for comparison, as in the
BART-applicability test, is more appropriate than the overall
comparison of the 20 percent worst case days, and that the threshold
for comparison should be on at least a daily average (or longer), not
an hourly average, due to the possibility of short-term spikes based on
certain meteorological conditions.
These commenters also said that a comparison of the number of days
above or below a certain threshold is preferable since below a certain
threshold, the impacts of visibility are not perceptible; unlike
concentration
[[Page 39129]]
levels of certain pollutants (i.e., ozone) which do not have a
threshold below which there are no effects, there are concentration
levels of particulate below which there is no visibility impact. They
also asserted that comparing the number of days would allow for a more
complete picture of how controls would potentially improve visibility.
As noted previously, a small number of unusual meteorological
conditions can produce significant spikes on a single day or days.
Since the overall goal of the regional haze rule is long-term
visibility improvement, they said that a comparison of the total number
of days exceeding a threshold over multiple years will provide a better
overall indicator of visibility improvement. One commenter suggested
that if we retain the maximum 24-hour value for the visibility
impairment analysis, we should at least allow the use of only 1 year,
rather than 5 years, of meteorological data. That would simplify the
modeling and would lessen the chance that one day with atypical,
extreme conditions would dictate the result.
One FLM supported our proposed method to determine visibility
improvement associated with installation of BART. However, with regard
to the use of hourly data instead of 24 hour data for the degree of
visibility improvement assessment, another FLM said that while hourly
model data are, by their nature, less reliable in predicting actual
conditions, a measure that reports the total number of hours above a
given threshold would still be a useful measure of the long-term effect
of BART control. They said we should require States to report a
combination of measures of the visibility improvement expected from
BART. Such measures would be the change in the 20 percent worst days as
well as a metric that examines the amount of time during a year that
the source's visibility impact would exceed a threshold with and
without BART.
Another utility commenter added that, if a BART control option
would result in no perceptible improvement in visibility at a Class I
area, then it is not a cost-effective option. This commenter said that
based on Pitchford and Malm (1994) \50\ and Henry (2002) \51\ a 2
deciview threshold of perception would be appropriate, with a 1
deciview threshold providing a margin of safety. Another commenter said
that we should clarify that visibility improvement differences among
BART control options should be considered insignificant if the
differences are less than the perceptibility threshold level, which
should be set in excess of 1 deciview. Other commenters said the
minimum threshold should be 1 deciview.
---------------------------------------------------------------------------
\50\ Pitchford, M. and Malm, W., ``Development and Applications
of a Standard Visual Index,'' Atmospheric Environment, V. 28, no. 5,
March 1994.
\51\ Henry, R.C. ``Just-Noticeable Differences in Atmospheric
Haze'', Journal of the Air & Waste Management Association, 52:1238-
1243, October 2002.
---------------------------------------------------------------------------
Final Rule. We disagree with the comment that modeling should not
be part of a BART review because it is not considered for BACT. CAA
section 169A(g)(2) clearly requires an evaluation of the expected
degree of improvement in visibility from BART controls. All five
statutory factors, including cost-effectiveness and expected visibility
improvement, should be reflected in the level of BART control that the
State implements. We believe that modeling, which provides model
concentration estimates that are readily converted to deciviews, is the
most efficient way to determine expected visibility improvement.
For the purposes of determining visibility improvement, States may
evaluate visibility changes on a pollutant-specific basis. If expected
improvement is shown from the various control choices, the State can
weigh the results with the other four BART determination factors when
establishing BART for a particular source. For example, a State can use
the CALPUFF model to predict visibility impacts from an EGU in
examining the option to control NOX and SO2 with
SCR technology and a scrubber, respectively. A comparison of visibility
impacts might then be made with a modeling scenario whereby
NOX is controlled by combustion controls. If expected
visibility improvements are significantly different under one control
scenario than under another, then a State may use that information,
along with information on the other BART factors, to inform its BART
determination.
Even though the visibility improvement from an individual source
may not be perceptible, it should still be considered in setting BART
because the contribution to haze may be significant relative to other
source contributions in the Class I area. Thus, we disagree that the
degree of improvement should be contingent upon perceptibility. Failing
to consider less-than-perceptible contributions to visibility
impairment would ignore the CAA's intent to have BART requirements
apply to sources that contribute to, as well as cause, such impairment.
Although we are not requiring States to use allowable emission
rates to predict the anticipated future visibility impacts of BART
controls, we disagree that daily average actual emission rates should
be used to make this assessment. Emissions from a source can vary
widely on a day to day basis; during peak operating days, the 24-hour
actual emission rate could be more than double the daily average. On
the other hand, in the long term, estimating visibility impacts based
on allowable emission rates for every hour of the year may unduly
inflate the maximum 24 hour modeled impairment estimate from a BART-
eligible source. The emissions estimates used in the models are
intended to reflect steady-state operating conditions during periods of
high capacity utilization. We do not generally recommend that emissions
reflecting periods of start-up, shutdown, and malfunction be used, as
such emission rates could produce higher than normal effects than would
be typical of most facilities. Where States have information on a
source's daily emissions, an emission rate based on the maximum actual
emissions over a 24 hour period for the most recent five years may be a
more appropriate gauge of a source's potential impact as it would
ensure that peak emission conditions are reflected, but would likely
not overestimate a source's potential impact on any given day. We have
accordingly included this change to the final guidelines. We recommend
that the State use the highest 24-hour average actual emission rate,
for the most recent three or five year period of meteorological data,
to characterize the maximum potential benefit.
Because each Class I area is unique, we believe States should have
flexibility to assess visibility improvements due to BART controls by
one or more methods, or by a combination of methods, and we agree with
the commenters suggestions to do so. We believe the maximum 24-hour
modeled impact can be an appropriate measure in determining the degree
of visibility improvement expected from BART reductions (or for BART
applicability). We have pointed out, however, that States should have
flexibility when evaluating the fifth statutory factor. A State is
encouraged to account for the magnitude, frequency, and duration of the
contributions to visibility impairment caused by the source based on
the natural variability of meteorology. These are important elements to
consider as they would provide useful information on both the short
term peak impact and long term average assessments which are critical
in making the visibility assessment.
We agree with the suggestion that the use of a comparison
threshold, as is
[[Page 39130]]
done for determining if BART-eligible sources should be subject to a
BART determination, is an appropriate way to evaluate visibility
improvement. However, we believe the States have flexibility in setting
absolute thresholds, target levels of improvement, or de minimis levels
since the deciview improvement must be weighed among the five factors,
and States are free to determine the weight and significance to be
assigned to each factor. For example, a 0.3, 0.5, or even 1.0 deciview
improvement may merit stronger weighting in one case versus another, so
one ``bright line'' may not be appropriate.
In addition, comparison thresholds can be used in a number of ways
in evaluating visibility improvement (e.g. the number of days or hours
that the threshold was exceeded, a single threshold for determining
whether a change in impacts is significant, a threshold representing an
x percent change in improvement, etc.). In our example modeling
analysis of a hypothetical source,\52\ we used three different 24-hour
thresholds (1.0, 0.5, and 0.1 deciviews) and examined the number of
days that those thresholds were exceeded for a source with a 90 percent
change, for example, in SO2 emissions (i.e. 10,000 TPY and
1,000 TPY). The number of days that the thresholds were exceeded in the
10,000 TPY case was substantial, and the visibility improvement due to
the reduction in emissions was dramatic (i.e. the number of days
exceeding the thresholds dropped considerably).\53\
---------------------------------------------------------------------------
\52\ CALPUFF Analysis in Support of the June 2005 Changes to the
Regional Haze Rule, U.S. Environmental Protection Agency, June 15,
2005, Docket No. OAR-2002-0076.
\53\ Ibid.
---------------------------------------------------------------------------
Other ways that visibility improvement may be assessed to inform
the control decisions would be to examine distributions of the daily
impacts, determine if the time of year is important (e.g. high impacts
are occurring during tourist season), consideration of the cost-
effectiveness of visibility improvements (i.e. the cost per change in
deciview), using the measures of deciview improvement identified by the
State, or simply compare the worst case days for the pre- and post-
control runs. States may develop other methods as well.
5. In What Sequence Should Alternatives Be Assessed in Step 5 of the
BART Determination?
Background. Both the 2001 proposal and the 2004 reproposal
requested comments on two options for evaluating the ranked options.
Under the first option, States would use a sequential process for
conducting the impacts analysis, beginning with a complete evaluation
of the most stringent control option. If a State determines that the
most stringent alternative in the ranking does not impose unreasonable
costs of compliance, taking into account both average and incremental
costs, the analysis begins with a presumption that this level is
selected. Under this option, States would then proceed to consider
whether energy and non-air quality environmental impacts would justify
selection of an alternative control option. If there are no outstanding
issues regarding energy and non-air quality environmental impacts, the
analysis is ended and the most stringent alternative is identified as
the ``best system of continuous emission reduction.'' If a State
determines that the most stringent alternative is unacceptable due to
such impacts, this approach would require them to document the
rationale for this finding for the public record. Then, the next most-
effective alternative in the listing becomes the new control candidate
and is similarly evaluated. This process would continue until the State
identifies a technology which does not pose unacceptable costs of
compliance, energy and/or non-air quality environmental impacts.
We also requested comment on an alternative decision-making
approach that would not begin with an evaluation of the most stringent
control option. For example, States could choose to begin the BART
determination process by evaluating the least stringent technically
feasible control option or by evaluating an intermediate control option
drawn from the range of technically feasible control alternatives.
Under this approach, States would then consider the additional
emissions reductions, costs, and other effects (if any) of successively
more stringent control options. Under such an approach, States would
still be required to (1) display all of the options and identify the
average and incremental costs of each option; (2) consider the energy
and non-air quality environmental impacts of each option; and (3)
provide a justification for adopting the technology selected as the
``best'' level of control, including an explanation of its decision to
reject the other control technologies identified in the BART
determination.
In selecting a ``best'' alternative, the proposed guidelines
included a discussion on whether the affordability of controls should
be considered. As a general matter, for plants that are essentially
uncontrolled at present and emit at much greater levels per unit of
production than other plants in the category, we believe it is likely
that additional control will be cost-effective. The proposed guidelines
noted, however, that we recognize there may be unusual circumstances
that justify taking into consideration the conditions of the plant and
the economic effects of requiring the use of a given control
technology. These effects would include effects on product prices, the
market share, and profitability of the source. We did not intend, for
example, that the most stringent alternative must always be selected if
that level would cause a plant to shut down, while a slightly lesser
degree of control would not have this effect.
Comments. We received comments supporting both of the approaches
for evaluating ranked control alternatives. Many commenters, including
commenters from State agencies, were supportive of the first approach.
Comments from State air quality agencies were strongly supportive of
this approach. These commenters believed that this approach is
consistent with past approaches by States for considering control
options for case-by-case determinations, is well understood by all
parties, and thus easier to implement. The first approach also was
strongly supported in comments from environmental organizations and
private citizens. Some comments noted that the plain terminology
``best'' suggests that there must be a sound reason for not using the
most stringent control level.
Many comments from industrial trade organizations were critical of
the first approach and believed that any requirement to use this
approach would reduce State discretion because this approach, in the
judgment of the commenters, would amount to use of the most stringent
alternative as a default. Some of these comments asserted that the
approach in option 1 would shift the BART analysis away from a cost-
benefit approach mandated by the CAA towards a BACT-like technology
analysis. Other commenters believed that EPA should recognize that
BART, as a control requirement for retrofitting existing sources,
should differ from BACT or other controls for new equipment. A number
of comments, in supporting the second approach, believed that this
approach provides greater consideration of the incremental cost of each
succeeding option.
Final rule. In the final guidelines, we have decided that States
should retain the discretion to evaluate control options in whatever
order they choose, so long as the State explains its analysis of the
CAA factors. We agree with
[[Page 39131]]
commenters who asserted that the method for assessing BART controls for
existing sources should consider all of the statutory factors.
6. What Should Be the Presumptive Limits for SO2 and
NOX for Utility Boilers?
Background. In the 2004 reproposal, we proposed that States, as a
general matter, should require EGUs greater than 250 MW in size at
power plants larger than 750 MW to control 95 percent of their
SO2 emissions, or control to within an SO2
emission range of 0.1 to 0.15 lb/mmBtu. We also proposed to establish a
rebuttable presumption that States should impose these BART
SO2 limits on all EGUs greater than 250 MW, regardless of
the size of the power plant at which they are located.
For NOX, we proposed that sources currently using
controls such as SCRs to reduce NOX emissions during part of
the year should be required to operate those controls year-round. For
power plants without post-combustion controls, we proposed to establish
a presumptive emissions limit of 0.20 lbs/mmbtu for EGUs greater than
250 MW in size. We requested comment on the rate of NOX
emissions that can be achieved with combustion modifications on
specific types of boilers. Many commenters responded both in favor and
in opposition to these proposed BART presumptive limits.
Comments. A number of utility groups said the presumptive
SO2 emissions control approach inappropriately ignores the
need for a visibility impact evaluation which is required in step 5 of
the proposed case-by-case BART engineering analysis. They said that
setting presumptive limits infringes on a state's authority to
establish BART on a case-by-case basis considering not only visibility
improvement, but the other statutory factors as well. The commenters
said that visibility is both Class I area and source specific, which is
the reason Congress gave the States the lead role and discretion in the
BART program to determine which sources need to install or upgrade
controls. Through the use of presumptions and default values, however,
our prescriptive process, as proposed, would make the installation of
maximum controls more likely without regard to visibility benefits.
Instead, they argued, we should give the states maximum flexibility to
use the five statutory factors in their BART determinations. Commenters
said sources must be allowed to assess the visibility improvements of a
variety of control options.
Several utilities raised concern that sources with existing
controls should not be required to meet the presumptive limits without
the chance to evaluate the degree of visibility improvement expected
from the additional emission reduction requirements. They said that if
a source can demonstrate a reduction in visibility impairment below the
specified threshold (whether that threshold is our currently proposed
0.5 deciview or an alternative level) with less stringent controls,
then neither we nor States should impose, by default, more stringent
reduction requirements.
Commenters from industry, utilities, and States said that we had
not indicated what previously-controlled sources must do to comply with
BART, while we had determined what controls are necessary for
uncontrolled sources. They were concerned that the guidelines would
lead States to require previously-controlled sources to remove the
controls and replace them with even newer controls at great cost and
very little, if any, improvement in emission levels and visibility in
Class I areas. Commenters added that States should be able to use their
discretion to determine whether additional controls are needed.
Some commenters were concerned that the proposed rule would require
some plants to install SCR to meet the NOX control level
proposed, as the potential retrofit of SCR technology for the BART
determination may be supported by the degree of visibility improvement
expected. They said that the guidelines indicate that if a State finds
that a source's visibility contribution warrants the installation of
SCR, then SCR may be imposed. The commenter added, however, that the
guidelines also need to provide for instances where the visibility
condition warrants a lesser control level than what would be achieved
by advanced combustion control; the commenter claimed there was
reference to this concept in the preamble but not the guidelines.
Final rule. In these guidelines, we are finalizing specific
presumptive limits for SO2 and NOX for certain
EGUs based on fuel type, unit size, cost effectiveness, and the
presence or absence of pre-existing controls. The presumptive limits
finalized in today's rulemaking reflect highly cost-effective
technologies as well as provide enough flexibility for States to take
particular circumstances into account.
The presumptive limits apply to EGUs at power plants with a total
generating capacity in excess of 750 MW. As explained in greater detail
below, for these sources we are establishing a BART presumptive
emission limit for coal-fired EGUs greater than 200 MW in size without
existing SO2 control. These EGUs should achieve either 95
percent SO2 removal, or an emission rate of 0.15 lb
SO2/mmBtu, unless a State determines that an alternative
control level is justified based on a careful consideration of the
statutory factors. For NOX, we are establishing a set of
BART presumptive emission limits for coal-fired EGUs greater than 200
MW in size based upon boiler size and coal type, and based upon whether
selective catalytic reduction (SCR) or selective noncatalytic reduction
(SNCR) are already employed at the source. See section d. below for a
table listing those specific limits. Based on our analysis of emissions
from power plants, we believe that applying these highly cost-effective
controls at the large power plants covered by the guidelines would
result in significant improvements in visibility and help to ensure
reasonable progress toward the national visibility goal.
States, as a general matter, must require owners and operators of
greater than 750 MW power plants to meet these BART emission limits. We
are establishing these requirements based on the consideration of
certain factors discussed below. Although we believe that these
requirements are extremely likely to be appropriate for all greater
than 750 MW power plants subject to BART, a State may establish
different requirements if the State can demonstrate that an alternative
determination is justified based on a consideration of the five
statutory factors.
In addition, while States are not required to follow these
guidelines for EGUs located at power plants with a generating capacity
of less than 750 MW, based on our analysis detailed below, we believe
that States will find these same presumptive controls to be highly-cost
effective, and to result in a significant degree of visibility
improvement, for most EGUs greater than 200 MW, regardless of the size
of the plant at which they are located. A State is free to reach a
different conclusion if the State believes that an alternative
determination is justified based on a consideration of the five
statutory factors. Nevertheless, our analysis indicates that these
controls are likely to be among the most cost-effective controls
available for any source subject to BART, and that they are likely to
result in a significant degree of visibility improvement.
The rest of this section discusses these presumptive limits for
SO2 and NOX for EGUs and the additional
[[Page 39132]]
visibility impact and cost-effectiveness analyses we have performed
since proposal of the guidelines in 2004.
a. Visibility Analysis for SO2 and NOX
Emissions From EGUs. In the 2004 reproposal, our preliminary CALPUFF
modeling \54\ suggested that controlling a single 250 MW EGU at a 90
percent level would improve visibility substantially from that source.
Based on the expected degree of improvement in visibility and the use
of highly effective control technologies that are available for sources
of this capacity and greater, we concluded that the specific control
levels in the proposal were appropriate. Even at that level of control
however, our analysis indicated that emissions from the source might
still cause a perceptible impact on visibility.
---------------------------------------------------------------------------
\54\ Summary of Technical Analyses for the Proposed Rule, Mark
Evangelista, U.S. Environmental Protection Agency, April 12, 2004,
Docket No. OAR-2002-0076.
---------------------------------------------------------------------------
Following comments that we had ignored the need to consider the
degree of improvement in visibility which could reasonably be
anticipated from the use of the presumptive control technologies, we
undertook a more comprehensive modeling analysis of the anticipated
visibility impacts of controlling large EGUs. Based on this modeling
analysis, we anticipate that a majority of the currently uncontrolled
EGUs at power plants covered by the guideline are predicted to have 24-
hour maximum impacts of greater than a change of 2 or 3 deciviews.\55\
Our modeling examples included scenarios that were representative of
typical EGUs, but, in our first hypothetical run 1, we
conservatively assumed SO2 emissions of 10,000 tons per year
(TPY) and NOX emissions of approximately 3,500 TPY.\56\ Such
levels of emissions are well below those that may be expected of an
uncontrolled 200 MW EGU. The number of days during any year that such
sources are predicted to have visibility impacts of greater than 0.5
deciviews or even 1.0 deciview were 29 days and 12 days on average,
respectively, at 50 km from a hypothetical Class I area in the East; if
the 98th percentile were considered, there would be five days above a
1.0 deciview change.
---------------------------------------------------------------------------
\55\ CALPUFF Analysis in Support of the the June 2005 Changes to
the Regional Haze Rule, U.S. Environmental Protection Agency, June
15, 2005, Docket No. OAR-2002-0076.
\56\ Ibid.
---------------------------------------------------------------------------
The modeled emission rates in the example were conservative; for
much larger EGUs with capacities of 750 MW or more, and emission rates
much higher than those which were modeled, visibility degradation is
expected to be far worse. Clearly there is a substantial degree of
visibility improvement which is likely from emission reductions at
these sources.
Although we are confident that the EGUs for which we are
establishing presumptive limits each have a significant impact on
visibility at one or more Class I areas, a State retains the option and
flexibility to conduct its own analysis or allow a source to
demonstrate that it should not be subject to BART (based on its
visibility effects).
b. BART Presumptive Limits for SO2 From Coal-Fired
Units. For currently uncontrolled coal-fired EGUs greater than 200 MW
in size located at power plants greater than 750 MW, we are
establishing a presumptive BART limits of 95 percent SO2
removal, or an emission rate of 0.15 lb SO2/mmBtu. We are
not establishing a presumptive limit for EGUs with existing post-
combustion SO2 controls or for EGUs that burn oil.
In 2004, we proposed presumptive limits for SO2 of 95
percent control or a comparable performance level of 0.1 to 0.15 lbs
per million BTU as controls that would be achievable and cost-
effective. We requested comment on the removal effectiveness of flue
gas desulfurization (``FGD'' or ``scrubber'' controls) for various coal
types and sulfur content combinations. Having considered the comments
received, we have determined that there is ample data to support the
determination that the BART presumptive limits outlined in today's
action are readily achievable by new wet or semi-dry FGD systems across
a wide range of coal types and sulfur contents based on proven scrubber
technologies currently operational in the electric industry.\57\
---------------------------------------------------------------------------
\57\ Technical Support Document for BART SO2 Limits for Electric
Generating Units, Memorandum to Docket OAR 2002-0076, April 1, 2005.
---------------------------------------------------------------------------
We agree with the commenters who stated that our dual
recommendation provided equity across sources burning coals of varying
sulfur content. We believe the presumptive limits provide enough
flexibility that absent unique circumstances, any BART-eligible coal-
fired EGU will be able to achieve one of the limits with a new FGD
system. We expect that BART-eligible EGUs burning medium to high sulfur
coal will be able to achieve a removal efficiency of 95 percent in a
cost effective manner by utilizing various wet FGD technologies, and
that those EGUs burning lower sulfur coals could meet the emission
limit of 0.15lb/mmBtu in a cost effective manner by utilizing dry FGD
technologies. As described below, EPA's unit specific economic modeling
showed that the majority of BART eligible units greater than 200 MW can
meet the presumptive BART limit at a cost of $400 to $2000 per ton of
SO2 removed.
Some commenters expressed concerns that the proposed limits were
too stringent in particular for: (1) EGUs less than 750 MW in size, (2)
EGUs burning low sulfur coals, and (3) EGUs burning lignite coals.
However, numerous examples exist of smaller EGUs and EGUs burning low
sulfur or lignite coals achieving these SO2 limits at
reasonable cost.\58\ We recognize that semi-dry FGD systems are most
commonly utilized on units burning lower sulfur coals and are not
typically designed for removal efficiencies of 95 percent or greater.
However, we believe that most of these EGUs can readily achieve the
presumptive emission rate limit of 0.15 lb SO2/mmBtu. An
analysis of EPA's RACT/BACT/LEAR Clearinghouse Dry FGD cost
effectiveness data ranged from $393 to $2132 per ton SO2
removed, with an average cost effectiveness of $792 per ton.\59\
---------------------------------------------------------------------------
\58\ Ibid.
\59\ Summary of BART Source Analyses, Memorandum from Bill
Balcke and Doran Stegura, Perrin Quarles Associates, Inc., to Chad
Whiteman, EPA March 24, 2003. See 2001 emissions data in BART AR
file, attached.
---------------------------------------------------------------------------
We received a few comments expressing the belief that the
presumptive limits should be more stringent, given that BART emission
limits will not be fully implemented until 2013 or 2014. We recognize
that while some scrubber units currently achieve reductions greater
than 95 percent, not all units can do so. The individual units that
currently achieve greater than 95 percent control efficiencies do not
necessarily represent the wide range of unit types across the universe
of BART-eligible sources. An analysis of the Department of Energy's
U.S. FGD Installation Database supports our belief that 95 percent
removal efficiencies would be obtainable by all types of EGUs burning
medium and high sulfur coal by 2014, including BART-eligible EGUs. In
addition, we note that the presumption does not limit the States'
ability to consider whether a different level of control is appropriate
in a particular case. If, upon examination of an individual EGU, a
State determines that a different emission limit is appropriate based
upon its analysis of the five factors, then the State may apply a more
or less stringent limit.
Our analysis of presumptive BART limits accounted for variations in
existing SO2 controls. We accordingly considered (1) coal-
fired EGUs without
[[Page 39133]]
existing SO2 controls, and (2) coal-fired EGUs with existing
SO2 controls. This analysis consisted of the following key
elements: (1) Identification of all potentially BART-eligible EGUs, and
(2) technical analyses and industry research to determine applicable
and appropriate SO2 control options, (3) economic analysis
to determine cost effectiveness for each potentially BART-eligible EGU,
and (4) evaluation of historical emissions and forecast emission
reductions for each potentially BART-eligible EGU.\60\
---------------------------------------------------------------------------
\60\ Ibid.
---------------------------------------------------------------------------
We identified 491 potentially BART-eligible coal-fired units based
on the following criteria: (1) The unit was put in place between August
7, 1962 and August 7, 1977, and (2) the unit had the potential to emit
more than 250 tons annually of SO2. Our assessment of
potential controls included various industry case studies, technical
papers, public comments, BACT analyses, and historical Acid Rain
emissions data. Our analysis is described in detail in the TSD.\61\
---------------------------------------------------------------------------
\61\ Ibid.
---------------------------------------------------------------------------
We calculated cost effectiveness and projected SO2
emission reductions on a per unit basis based on removal efficiencies
of 90 percent for dry FGD systems, in particular spray dry lime
systems, and 95 percent for wet FGD systems, in particular limestone
forced oxidation systems. Based on our analysis, the average cost
effectiveness for controlling all BART-eligible EGUs greater than 200
MW without existing SO2 controls was estimated to $919 per
ton of SO2 removed. Moreover, the range of costs
effectiveness numbers demonstrates that the majority of these units can
meet the presumptive limits at a cost of $400 to $2000 per ton of
SO2 removed.
Figure 1
----------------------------------------------------------------------------------------------------------------
Calculated Percent of
Percent of BART average cost estimated
Unit capacity (MW) Tons (K) of SO2 eligible coal- effectiveness for removable BART SO2
emitted in 2001 fired unit's 2001 MW grouping ($/ emissions from
emissions ton SO2 removed) coal-fired units*
----------------------------------------------------------------------------------------------------------------
<50 MW............................ 26 0.4 1962 0.9
50-100 MW......................... 93 1.4 2399 1.6
100-150 MW........................ 171 2.5 1796 2.2
150-200 MW........................ 235 3.5 1324 3.4
200-250 MW........................ 253 3.8 1282 3.1
250-300 MW........................ 281 3.2 1128 4.0
>300 MW........................... 5712 85.2 ................. 84.8
All Units......................... 6707 100 984 100
BART Units (>200MW)............... 6246 92.2 919 91.9
----------------------------------------------------------------------------------------------------------------
In establishing presumptive BART limits, we were cognizant of the
fact that upgrading an existing scrubber system is typically considered
more cost effective than constructing a new scrubber system. However,
due to the diverse and complex nature of upgrading existing FGD systems
(scrubber type, reagents, online year, absorber characteristics,
current operating procedures, etc.), there is no single solution or
standard appropriate for all EGUs. As a result, we are not including
specific numerical presumptive limits for EGUs with pre-existing
scrubbers. However, for scrubbers currently achieving removal
efficiencies of at least 50 percent, we recommend States evaluate a
range of scrubber upgrade options available for improving the
SO2 removal performance of existing units. There are
numerous scrubber enhancements available to upgrade the average removal
efficiencies of all types of existing scrubber systems, and the
guidelines contains a discussion of the options that States should
evaluate in making BART determinations for EGUs with existing
scrubbers.
The guidelines do not require EGUs with existing FGD systems to
remove these controls and replace them with new controls, but the
guidelines do state that coal fired EGUs with existing SO2
controls achieving removal efficiencies of less than 50 percent should
consider constructing a new FGD system to meet the presumptive limits
of 95 percent removal or 0.15 lb/mmBtu in addition to evaluating the
suite of upgrade options. For these EGUs, the suite of available
``upgrades'' may not be sufficient to remove significant SO2
emissions in a cost effective manner, and States may determine that
these EGUs should be retrofitted with new FGD systems.
c. BART Limits for SO2 From Oil-Fired Units. We are not
establishing a presumptive BART limit for SO2 from oil-fired
EGUs. The guidelines state that the most appropriate control option for
oil-fired EGUs, regardless of capacity, is to set limits on the sulfur
content of the fuel oil burned in the unit.
Commenters suggested EPA evaluate two primary control options for
BART oil-burning units: (1) Sulfur content fuel oil limitations, and
(2) flue gas desulfurization systems. We have been unable to find any
FGD application in the U.S. electric industry on an oil-fired unit. As
a result, our analysis for oil-fired units focused on benchmarking
previously imposed fuel oil restrictions on the electric industry and
(2) a regional economic analysis of switching from high sulfur to low
sulfur fuel oil.
Our study of currently imposed fuel oil restrictions on the
electric industry suggested that all BART-eligible EGUs currently have
some sort of imposed sulfur content or emission rate limitation. Of the
74 BART-eligible oil-burning EGUs, 32 currently have sulfur fuel oil
restrictions of less than 1 percent, and 67 have some sort of sulfur
content limitation. In addition, our economic analysis suggests that
switching to low sulfur fuel oil is a cost effective method in reducing
SO2 emission from oil fired units.
As approximately 43 percent of the BART eligible oil units
currently have a sulfur content limitation that is either equivalent
to, or more stringent than, one percent sulfur by weight, the
guidelines require States to consider a one percent or lower sulfur by
weight fuel oil restriction on all BART eligible EGUs as part of their
BART analysis, and recommends that States establish appropriate and
sustainable sulfur content fuel oil restrictions, taking into
[[Page 39134]]
account fuel oil availability. States should accordingly evaluate a one
percent sulfur content limitation as a starting point of their BART
determination for oil-fired EGUs subject to BART.
d. BART Presumptive Limits for NOX From Coal-fired Units. In the
2004 reproposal, in discussing NOX controls on EGUs, we
explained that there are two somewhat distinct approaches to reducing
emissions of NOX at existing sources. One is to use
combustion controls (including careful control of combustion air and
low-NOX burners). The other approach is removal technology
applied to the flue gas stream (such as SCRs and SNCRs).
For EGUs currently using controls such as SCRs or SNCRs to reduce
NOX during part of the year, we are establishing a
presumption that use of these same controls year-round is BART. (Some
commenters supported year-round operation of these controls. One
commenter suggested the cost of year-round operation of SCRs would be
significant. However, our analysis showed year-round operation of
existing SCRs compared to operation during the 5-month ozone season
only to be highly cost effective (average cost-effectiveness of $170
per ton).) Although only a few BART-eligible sources currently have
SNCRs installed, we note that States may wish to consider SCR as an
alternative to annual operation of SNCR in light of the relatively high
operating costs associated with SNCR.
For sources without post-combustion controls (i.e., SCRs and
SNCRs), we are establishing a presumption as to the appropriate BART
limits for coal-fired units based on boiler design and coal type. These
presumptions apply to EGUs greater than 200 MW at power plants with a
generating capacity greater than 750 MW and are based on control
strategies that are generally cost-effective for all such units.
In 2004 we noted that, unlike the methods for controlling
SO2 (which fall within a fairly narrow range of cost
effectiveness and control efficiencies), the removal efficiencies and
costs associated with the control techniques for NOX vary
considerably, depending on the design of the boiler and the type of
coal used. In response to comments on the proposal, we have performed
additional analyses of all individual BART-eligible coal-fired units
\62\ and our analyses indicated that both cost effectiveness and post-
control rates for NOX do depend largely on boiler design and
type of coal burned. Based on these analyses, we believe that States
should carefully consider the specific NOX rate limits for
different categories of coal-fired utility units, differentiated by
boiler design and type of coal burned, set forth below as likely BART
limits.
---------------------------------------------------------------------------
\62\ See Technical Support Document for BART NOX
Limits for Electric Generating Units and Technical Support Document
for BART NOX Limits for Electric Generating Units Excel
Spreadsheet, Memorandum to Docket OAR 2002-0076, April 15, 2005.
---------------------------------------------------------------------------
In today's action, EPA is setting presumptive NOX limits
for EGUs larger than 750 MW. EPA's analysis indicates that the large
majority of the units can meet these presumptive limits at relatively
low costs. Because of differences in individual boilers, however, there
may be situations where the use of such controls would not be
technically feasible and/or cost-effective. For example, certain
boilers may lack adequate space between the burners and before the
furnace exit to allow for the installation of over-fire air controls.
Our presumption accordingly may not be appropriate for all sources. As
noted, the NOX limits set forth here today are presumptions
only; in making a BART determination, States have the ability to
consider the specific characteristics of the source at issue and to
find that the presumptive limits would not be appropriate for that
source.
The table below indicates the types of boilers installed at the 491
BART-eligible coal-fired EGUs. Dry-bottom wall-fired boiler units and
tangentially-fired boiler units make up a large majority of the total
BART-eligible EGUs.
Table 1.--Population of BART-Eligible Coal-Fired EGUs
----------------------------------------------------------------------------------------------------------------
Number Number Number
-----------------------------------------------------
Boiler type Units > 200 MW
All units Units > 200 MW at 750 MW plants
----------------------------------------------------------------------------------------------------------------
Cyclone................................................... 56 35 19
Cell Burner............................................... 35 35 29
Dry Bottom--Wall fired.................................... 188 121 77
Dry Bottom Turbo-fired.................................... 14 10 4
Stoker.................................................... 5 0 0
Tangentially-fired........................................ 186 164 112
Wet Bottom................................................ 6 5 5
Other..................................................... 1 0 0
-------------------
Total BART-eligible coal-fired EGUs................... 491 370 246
----------------------------------------------------------------------------------------------------------------
For all types of boilers other than cyclone units, the limits in
Table 2 are based on the use of current combustion control technology.
Current combustion control technology is generally, but not always,
more cost-effective than post-combustion controls such as SCRs. For
cyclone boilers, SCRs were found to be more cost-effective than current
combustion control technology;\63\ thus the NOX limits for
cyclone units are set based on using SCRs. SNCRs are generally not
cost-effective except in very limited applications and therefore were
not included in EPA's analysis. The types of current combustion control
technology options assumed include low NOX burners, over-
fire air, and coal reburning.
---------------------------------------------------------------------------
\63\ The current combustion control technology EPA analyzed for
cyclone units is coal reburning.
---------------------------------------------------------------------------
We are establishing presumptive NOX limits in the
guidelines that we have determined are cost-effective for most units
for the different categories of units below, based on our analysis of
the expected costs and performance of controls on BART-eligible units
greater than 200 MW. We assumed that coal-fired EGUs would have space
available to install separated over-fire air. Based on the large number
of units of various boiler designs that have installed separated over-
fire air, we believe this assumption to be reasonable. It is
[[Page 39135]]
possible, however, that some EGUs may not have adequate space
available. In such cases, other NOX combustion control
technologies could be considered such as Rotating Opposed Fire Air
(``ROFA''). The limits provided were chosen at levels that
approximately 75 percent of the units could achieve with current
combustion control technology. The costs of such controls in most cases
range from just over $100 to $1000 per ton. Based on our analysis,
however, we concluded that approximately 25 percent of the units could
not meet these limits with current combustion control technology.
However, our analysis indicates that all but a very few of these units
could meet the presumptive limits using advanced combustion controls
such as rotating opposed fire air (``ROFA''), which has already been
demonstrated on a variety of coal-fired units. Based on the data before
us, the costs of such controls in most cases are less than $1500 per
ton.
---------------------------------------------------------------------------
\64\ No Cell burners, dry-turbo-fired units, nor wet-bottom
units burning lignite were identified as BART-eligible, thus no
presumptive limit was determined. Similarly, no wet-bottom units
burning sub-bituminous were identified as BART-eligible.
\65\ These limits reflect the design and technological
assumptions discussed in the technical support document for
NOX limits for these guidelines, e.g., EPA assumed space
would be available for over-fire air. See Technical Support Document
for BART NOX Limits for Electric Generating Units and
Technical Support Document for BART NOX Limits for Electric
Generating Units Excel Spreadsheet, Memorandum to Docket OAR 2002-
0076, April 15, 2005.
Table 2.--Presumptive NOX Emission Limits for BART-Eligible Coal-Fired
Units \64\
------------------------------------------------------------------------
NOX presumptive
Unit type Coal type limit (lb/mmbtu)
\65\
------------------------------------------------------------------------
Dry-bottom wall-fired......... Bituminous............ 0.39
Sub-bituminous........ 0.23
Lignite............... 0.29
Tangential-fired.............. Bituminous............ 0.28
Sub-bituminous........ 0.15
Lignite............... 0.17
Cell Burners.................. Bituminous............ 0.40
Sub-bituminous........ 0.45
Dry-turbo-fired............... Bituminous............ 0.32
Sub-bituminous........ 0.23
Wet-bottom tangential-fired... Bituminous............ 0.62
------------------------------------------------------------------------
Table 3.--Average Cost-Effectiveness of NOX Controls for BART-Eligible Coal-Fired Units
----------------------------------------------------------------------------------------------------------------
Number units National average
Unit type Coal type nation-wide ($/ton)
----------------------------------------------------------------------------------------------------------------
Dry-bottom wall-fired.................... Bituminous....................... 114 1229
Sub-bituminous................... 66 576
Lignite.......................... 3 1296
Tangential-fired......................... Bituminous....................... 105 567
Sub-bituminous................... 72 281
Lignite.......................... 9 614
Cell Burners............................. Bituminous....................... 32 1287
Sub-bituminous................... 3 1021
Dry-turbo-fired.......................... Bituminous....................... 7 775
Sub-bituminous................... 7 599
Wet-bottom............................... Bituminous....................... 6 378
Cyclones (with SCR)...................... All.............................. 56 900
----------------------------------------------------------------------------------------------------------------
The advanced combustion control technology we used in our analysis,
ROFA, is recently available and has been demonstrated on a variety of
unit types. It can achieve significantly lower NOX emission
rates than conventional over-fire air and has been installed on a
variety of coal-fired units including T-fired and wall-fired units. We
expect that not only will sources have gained experience with and
improved the performance of the ROFA technology by the time units are
required to comply with any BART requirements, but that more
refinements in combustion control technologies will likely have been
developed by that time. As a result, we believe our analysis and
conclusions regarding NOX limits are conservative.\66\ For
those units that cannot meet the presumptive limits using current
combustion control technology, States should carefully consider the use
of advanced combustion controls such as ROFA in their BART
determination.
---------------------------------------------------------------------------
\66\ See Technical Support Document for BART NOX Limits for
Electric Generating Units and Technical Support Document for BART
NOX Limits for Electric Generating Units Excel Spreadsheet,
Memorandum to Docket OAR 2002-0076, April 15, 2005.
---------------------------------------------------------------------------
A detailed discussion of our analysis is in the docket.\67\ For
data on emissions and existing control technology in use at the BART-
eligible EGUs, we used EPA's Clean Air Markets Division database.\68\
---------------------------------------------------------------------------
\67\ Id.
\68\ Reporting requirements for the Acid Rain Program and
NOX SIP Call affected sources, see 40 CFR 75 subpart G
(parts 7562-64), and EPA Clean Air Markets Division Web site, data
and maps page (http://www.epa.gov/airmarkets).
---------------------------------------------------------------------------
C. Selective Catalytic Reduction (``SCR'') and Cyclone Units
We also analyzed the installation of SCRs at BART-eligible EGUs,
applying SCR to each unit and fuel type. The cost-effectiveness was
generally higher than for current combustion control technology except
for one unit type, cyclone units. Because of the relatively high
NOX emission rates of cyclone units, SCR is more cost-
effective. Our analysis indicated that the cost-effectiveness of
applying SCR on coal-fired cyclone units is typically less than $1500 a
ton, and that the average cost-
[[Page 39136]]
effectiveness is $900 per ton.\69\ As a result, we are establishing a
presumptive NOX limit for cyclone units based on the use of
SCR. For other units, we are not establishing presumptive limits based
on the installation of SCR. Although States may in specific cases find
that the use of SCR is appropriate, we have not determined that SCR is
generally cost-effective for BART across unit types.
---------------------------------------------------------------------------
\69\ See Technical Support Document for BART NOX Limits for
Electric Generating Units and Technical Support Document for BART
NOX Limits for Electric Generating Units Excel Spreadsheet,
Memorandum to Docket OAR 2002-0076, April 15, 2005.
---------------------------------------------------------------------------
Oil and Gas-Fired Units
For oil-fired and gas-fired units, we believe that installation of
current combustion control technology is highly cost-effective and
should be considered in determining BART for these sources. We
performed an analysis of BART-eligible oil and gas-fired units similar
to the analysis done for coal-fired units. Our analysis indicated that
a number of units can make significant reductions in NOX
emissions which are cost-effective through the application of current
combustion control technology.\70\ However, for a number of units, the
use of combustion controls does not appear to be cost-effective. As a
result, we determined that it would be inappropriate to establish a
general presumption regarding likely BART limits. As a result, the
guidelines only indicate that States should consider the installation
of current combustion control technology on oil and gas-fired units.
---------------------------------------------------------------------------
\70\ Id.
---------------------------------------------------------------------------
IV. How Does Today's Rule Affect States Options for Using Alternative
Strategies in Lieu of Source-by-Source BART?
Background
Over the past several years, there have been a number of rule
makings and court decisions on the subject of BART and BART-alternative
programs. In order to understand today's actions, it is useful to again
review the regulatory and litigation history, with a specific focus on
BART-alternative issues.
As noted in part I of this preamble, the 1999 regional haze rule
included provisions for BART, codified at 40 CFR 51.308(e), and in
definitions that appear in 40 CFR 51.301. Among these provisions was
section 308(e)(2), allowing States to implement cap and trade programs,
or other alternative programs, in lieu of BART. Section 308(e)(2)
provided that trading program alternatives must be demonstrated to
achieve greater reasonable progress than BART, and provided the general
parameters for making this demonstration. Of particular relevance,
section 308(e)(2) directed States, in the course of estimating
emissions reductions anticipated from source-by-source BART, to
determine what comprises BART based on the four non-visibility factors,
and then estimate visibility improvements based on the application of
BART to all sources subject to BART. In other words, section 308(e)(2)
indicated that states should use what has since been termed a ``group
BART'' approach to estimating the source-by-source BART benchmark, for
comparison to the alternative program. Section (e)(2) did not prescribe
the specific criteria to be used to compare the progress estimated from
source-by-source BART to that anticipated from the trading program. The
preamble discussion indicated that the comparison should be based on
both emission reductions and visibility improvement, but did not
provide further specificity. See 64 FR at 35741-35743.
Specific criteria for making the comparison to programs was
proposed in the BART Guidelines (40 CFR 51 App. Y) in 2001. These
criteria--sometimes referred to as the ``better-than-BART test''
consist of the following. First, if the geographic distribution of
emissions reductions from the two programs is expected to be similar,
the comparison can be made based on emissions alone. Second, if the
distribution of emissions reductions is anticipated to be significantly
different, then a two-pronged visibility improvement test is employed.
The first prong is that the alternative program must not result in a
degradation of visibility at any Class I area. The second prong is that
the alternative program must result in greater visibility improvement
overall, based on an average across all affected Class I areas. See 66
FR 38133.
In 2002, the D.C. Circuit decided American Corn Growers. The court
in that decision invalidated ``the BART provisions'' on the basis that
EPA had improperly constrained State authority by requiring them to
bifurcate visibility from the other statutory factors when making BART
determinations, and by specifying that visibility impairment should be
considered on a group basis when determining whether a BART eligible
source is subject to BART. 291 F.3d 1, 8.
Because EPA's policy of allowing alternative programs to BART was
not at issue in American Corn Growers, the decision contained no
discussion of how such alternative programs would be compared to BART--
neither the step of estimating emissions from source-by-source BART,
nor the criteria for the actual comparison (i.e., the test). Therefore,
EPA interpreted the court's vacature of the BART provisions to apply to
the source-by-source BART regulations under 40 CFR 51.308(e)(1).
Accordingly, in our May 2004 reproposal of the BART guidelines, we did
not propose any changes in section 308(e)(2), and we retained the
section on trading programs in the guidelines (Appendix Y) as that
section was proposed in 2001.
In June 2004, in the Supplemental Notice of Proposed Rulemaking
(SNPR) for the Clean Air Interstate Rule (CAIR), we proposed to
conclude that the CAIR will achieve greater reasonable progress than
would BART for SO2 and NOX at BART-eligible EGUs
in CAIR affected States and therefore may be treated as a program in
lieu of BART for those sources. In doing so, we discussed regional haze
rule section 308(e)(2) as precedent for the policy of allowing trading
programs to substitute for BART.\71\ However, noting that the CAIR
trading program affected only one category of BART-eligible sources
(EGUs), rather than all BART-eligible categories as envisioned for
State-developed BART-alternative programs under section 308(e)(2), we
proposed adding a 308(e)(3) applicable only to CAIR. This section would
provide that states that comply with the CAIR by subjecting EGUs to the
EPA administered cap and trade program may consider BART satisfied for
NOX and SO2 from BART-eligible EGUs. In the CAIR
SNPR and supporting documentation,\72\ we provided analyses
demonstrating that CAIR would achieve greater emission reductions than
BART, and would make greater reasonable progress according to the two-
pronged visibility test previously proposed in the BART guidelines.
---------------------------------------------------------------------------
\71\ Section 308(e)(2) was based, in turn, on the precedent set
by our interpretation of CAA 169A(b)(2) in a single BART-source
context--see 64 FR 35739, citing Central Arizona Water Conservation
District, 990 F.2d 1531 (1993).
\72\ ``Supplemental Air Quality Modeling Technical Support
Document (TSD) for the Clean Air Interstate Rule (CAIR), May,
2004.'' http://www.epa.gov/cair/pdfs/saqmtsd.pdf.
---------------------------------------------------------------------------
In February 2005, in CEED v. EPA, the D.C. Circuit invalidated a
BART-alternative program developed by the Western Regional Air
Partnership (WRAP), which was also based on a requirement of group-BART
analysis in setting source-by-source benchmark. It is important to note
that the two-pronged better-than-BART test was not
[[Page 39137]]
at issue in CEED, as neither the States nor EPA had employed that test
in determining that the WRAP's program achieved greater progress than
BART. The issue on which the court based its decision was not how the
two programs were compared, but how States were required to estimate
reductions from source-by-source BART in order to make the comparison.
The implications of this case to today's action are discussed in more
detail below.
Finally, on March 10, 2005 we promulgated the final CAIR. In the
final CAIR, we presented refined and updated analyses continuing to
show that CAIR makes greater progress than BART. We concluded at that
time that we should defer a final ``better than BART'' determinations
until (1) the source-by-source BART guidelines for EGU were
promulgated, and (2) the criteria for comparing alternatives to BART
were also finalized. We are taking both of those actions today, and, as
explained below, are therefore also making our final determination that
CAIR achieves greater progress than BART and may be used by States as a
BART substitute.
Final Criteria for Comparing Visibility Progress of an Alternative
Program to BART
Proposed Rule. As noted, the criteria for determining if an
alternative measure achieves greater reasonable progress than BART
(also known as the ``better than BART'' test or the two- pronged
visibility test) were first proposed in the 2001 BART guideline
proposal and reproposed in the identical form in the 2004 BART
guidelines reproposal. The test appeared as an element of the
guideline's overview of the steps involved in developing a trading
program consistent with regional haze rule section 308(e)(2).
Specifically, the guidelines provided that States could first look
at the geographic distribution of emissions under the trading program.
``If [the] distribution of emissions is not substantially different
than under BART, and greater emissions reductions are achieved, then
the trading program would presumptively achieve ``greater reasonable
progress.'' (69 FR at 25231). If the distribution of emissions is
expected to be different, then States are directed to conduct an air
quality modeling study. The guidelines then provide that
``[t]he modeling study would demonstrate ``greater reasonable
progress'' if both of the following two criteria are met:
--Visibility does not decline in any Class I area, and
--Overall improvement in visibility, determined by comparing the
average differences over all affected Class I areas
Comments Received
Several commenters stated that the trading criteria contained in
the proposed BART guidelines were, along with other parts of the
guidelines, beyond EPA's authority to impose under the CAA.
Several State commenters asked for clarification of what should be
considered a significantly different geographic distribution of
emission reductions, for purposes of proceeding to the two-pronged
visibility test.
One comment, submitted by environmental groups in response to our
preliminary application of the two-pronged test to the CAIR in the CAIR
rulemaking, goes to the permissibility of that test in general and is
therefore relevant to the finalization of the test. Specifically, these
commenters stated that because section 169A(b)(2)(A) requires BART for
an eligible source which may reasonably be anticipated to cause or
contribute to any impairment of visibility in any Class I area, EPA is
without basis in law or regulation to base a better-than-BART
determination on an analysis that uses averaging of visibility
improvement across different Class I areas.
Final Action. We are amending the regional haze rule to incorporate
the two- prong visibility test as it was previously proposed in the
BART guideline proposals. Specifically, we are adding the test to the
rule provisions at section 51.308(e)(3).
The EPA has the authority to prescribe this methodology under its
general rulemaking authority provided by CAA section 301(a), and under
CAA sections 169A(4) and 169(e). The latter provisions require EPA to
promulgate regulations to assure reasonable progress towards the
national visibility goal and to assure compliance with the requirements
of section 169A, which include the requirements for BART under section
169A(b)(2)(A), and to promulgate such measures as may be necessary to
carry out these regulations. The EPA has determined that source-by-
source BART need not be required when it is not necessary to meet
reasonable progress because greater progress can be achieved by an
alternative means. The D.C. Circuit in CEED upheld this interpretation
of the BART provisions' relationship to the broader reasonable progress
requirements of the Act. 398 F.3d at 660. In order to assure that such
alternative programs meet the reasonable progress goals of the CAA, EPA
has the authority, and perhaps a duty, to promulgate regulations
governing how that determination is made.
Moreover, these requirements for making the ultimate comparison
between an alternative program and BART do not affect in any way how
states make BART determinations or how they determine which sources are
subject to BART. It is in those areas where the Act and legislative
history indicate that Congress evinced a special concern with insuring
that States would be the decision makers. Nothing in American Corn
Growers or CEED suggests that those cases rendered EPA's rulemaking
authority under section 169A(a)(4) completely inoperable in any BART
context.
With respect to the use of average overall improvement, we
explained in the CAIR NFR preamble that we disagree with comments that
CAA section 169A(b)(2)'s requirement of BART for sources reasonably
anticipated to contribute to impairment at any Class I area means that
an alternative to the BART program must be shown to create improvement
at each and every Class I Area. Even if a BART alternative is deemed to
satisfy BART for regional haze purposes, based on average overall
improvement as opposed to improvement at each and every Class I Area,
CAA section 169A(b)(2)'s trigger for BART based on impairment at any
Class I area remains in effect, because a source may become subject to
BART based on ``reasonably attributable visibility impairment'' at any
area. See 40 CFR 51.302. In addition, within a regional haze context,
not every measure taken is required to achieve a visibility improvement
at every class I area. BART is one component of long term strategies to
make reasonable progress, but it is not the only component. The
requirement that the alternative achieves greater progress based on the
average improvement at all Class I areas assures that, by definition,
the alternative will achieve greater progress overall. Though there may
be cases where BART could produce greater improvement at one or more
class I areas, the no-degradation prong assures that the alternative
will not result in worsened conditions anywhere than would otherwise
exist, and the possibility of BART for reasonably attributable
visibility protects against any potential ``hot spots.'' Taken
together, the EPA believes these factors make a compelling case that
the proposed test properly defines ``greater reasonable progress.'' The
EPA anticipates that regional haze implementation plans will also
contain measures addressing other sources as
[[Page 39138]]
necessary to make progress at every mandatory Federal Class I area.
We are therefore finalizing the test criteria in the same form in
which they were proposed as part of the BART guidelines. We also
recognize that the test criteria leave some terms and conditions
undefined, and we believe States and Tribes should retain the
discretion to reasonably interpret and apply these terms as appropriate
to the context of the particular program at issue.
First, in the proposed test we did not specify the time period
which should serve as the starting point for comparison under the first
prong. That is, we did not specify whether potential degradation should
be determined in relation to visibility conditions existing at the time
of the proposed program, or in relation to base case visibility
projections for the time of program implementation. While either option
is, we believe, reasonable, in this rulemaking we have used the future
projected base case, for the following reasons.
The underlying purpose of both prongs of the test is to assess
whether visibility conditions at Class I areas would be better with the
alternative program in place than they would without it. The first
prong ensures that the program does not cause a decline in visibility
at any particular Class I area. It addresses the possibility that the
alternative program might allow local increases in emissions which
could result in localized degradation. The second prong assesses
whether the alternative program produces greater visibility improvement
in the aggregate than would source specific BART.
In both cases, the logical reference point is visibility conditions
as they are expected to be at the time of program implementation but in
the absence of the program. This insures that the visibility
improvements or degradations determined are due to the programs being
compared--source-specific BART and the cap-and-trade alternative--and
not to other extrinsic factors. For example, if large increases in wild
land fires are expected, due to accumulation of fuel from past forest
management practices, a degradation of visibility from current
conditions may be expected. It would be irrational to disapprove an
alternative program because of a modeled degradation from current
conditions, where that degradation is actually anticipated because of
smoke from such fires--sources which are not subject to the CAA BART
provisions. By comparing the alternative to future projected baseline
conditions, such extrinsic variables are accounted for. We are thus
able to ascertain (to the extent possible where future projections are
concerned) whether visibility under the alternative would decline at
any Class I area, all other things being equal.
Therefore, in applying the test to the CAIR, we used the future
(2015) projected baseline. We believe, however, that States should have
discretion in determining the most appropriate baseline for this prong
of the test, as long as the State's method is reasonable.
Second, although the proposed test indicated that dispersion
modeling should be used to determine visibility differences for the
worst and best 20 percent of days, the guideline did not specify the
relationship between the worst and best days and the two prongs of the
test. We believe that each prong of the test should ideally be based on
an examination of both the worst and best 20 percent of days. Thus,
under the first prong, visibility must not decline at any one Class I
area on either the best 20 percent or the worst 20 percent days \73\ as
a result of implementing the alternative program; and, under the second
prong both the best and worst days should be considered in determining
whether the alternative program produces greater average improvement.
---------------------------------------------------------------------------
\73\ The regional haze rule requires States to establish
reasonable progress goals for each Class I area that provide for
improvement in visibility for the most impaired days and ensure no
degradation in visibility for the most impaired days. The reasonable
progress test in the regional haze rule remains as a separate test
from better than BART. The SIPs must contain measures to achieve the
reasonable progress goal; such measures could include not only
stationary source programs such as BART but also programs to address
emissions from other types of sources. The no degradation (on the 20
percent best days) component of the reasonable progress test must
still be applied to the final future year emissions control
strategy. This does not directly impact the conclusions of the
better than BART test.
---------------------------------------------------------------------------
Third, the proposed guidelines did not define ``affected'' Class I
areas for purposes of the comparison. In applying the test to the CAIR,
we considered all federal mandatory Class I areas in the contiguous 48
States for which data was available. The principal Class I areas
affected by the CAIR are those in the eastern U.S., therefore we
calculated average improvement separately for the eastern areas, but
also considered affects at all Class I areas nationally. We believe
this was appropriate for a federally mandated program of the scope and
magnitude of the CAIR. However, this may not be necessary for every
BART-alternative program developed by States in the future, especially
if proposed programs are limited to smaller geographic areas or are
limited to source categories having significantly less widespread
impacts than EGUs. In such circumstances, it may be reasonable for the
States and Tribes involved to develop criteria for ``affected'' Class I
areas. For example, the affected region could be considered to be the
States and Tribes involved in the trading program as well as
immediately adjacent States, or Class I areas within adjacent States
that are within some defined distance of participating States.
With respect to comments on the degree of difference in the
geographic distribution of emissions necessary to trigger application
of the two prong test, we believe it is not necessary for EPA to define
that in the rule. For our CAIR analysis, we explained in the SNPR that
the fact that CAIR would produce greater emissions reductions than BART
in most States, but less reductions than BART in a few States, was
sufficient reason to employ the two pronged visibility test, 69 FR
32704. For other programs developed by States, a State would have the
ability to make a reasonable decision as to whether there was a
sufficient basis to make the demonstration that an alternative program
would be better than BART based on modeling of the emissions
distributions alone, or whether the State should proceed with the two-
pronged visibility test. The State's discretion is subject as always to
the condition that it must be reasonably exercised, and must be
supported by adequate documentation of the analyses.
Finally, on a related issue, we note that in a separate rule making
to follow soon after today's action, we will be soliciting comments on
whether there might be other means of demonstrating that an alternative
program makes greater reasonable progress than BART, in addition to the
two-pronged visibility test we are finalizing in today's action. Such
other means might take into account additional policy considerations,
as well as the relative degree of visibility improvement of the two
programs.
C. Final Determination That CAIR Makes Greater Reasonable Progress Than
BART
Proposal. As noted in the background section above, in both the
CAIR SNPR, and NFR, we discussed the proposed approach of allowing
States to treat CAIR as an in-lieu-of BART program for EGUs in CAIR-
affected States. In both actions, we presented analyses based on
emission projections and air quality modeling showing that CAIR will
achieve greater reasonable progress
[[Page 39139]]
towards the national visibility goal than would BART for affected EGUs.
These analyses were conducted according to the criteria for making such
``better than BART'' determinations which had been proposed in the BART
guidelines, and which have now been finalized in the regional haze rule
at 40 CFR 51.308(e)(3), as discussed above in section IV.B. Below, we
briefly recap these prior analyses. See 69 FR 32684, 32702-32707 and 70
FR 25162, 25299-25304 and associated Technical Support Documents \74\
for full details.
---------------------------------------------------------------------------
\74\ Supplemental Air Quality Modeling Technical Support
Document (TSD) for the Clean Air Interstate Rule (CAIR), May, 2004.
http://www.epa.gov/cair/pdfs/saqmtsd.pdf; Demonstration that CAIR
Satisfies the `Better-than-BART' Test as proposed in the Guidelines
for Making BART Determinations, EPA Docket Number OAR-2003-0054-
YYYY, March 2005. http://www.epa.gov/cair/pdfs/finaltech04.pdf.
---------------------------------------------------------------------------
Scenarios Examined
The CAIR is applicable to 28 States and the District of Columbia
and requires levels of SO2 and NOX emissions
reductions based on those achievable on a highly cost effective basis
from EGUs. BART, on the other hand, is applicable nationwide and covers
25 additional industrial categories, as well as EGUs, of a certain
vintage. In our comparison, we sought to determine whether the CAIR cap
and trade program for EGUs will achieve greater reasonable progress
than would BART for EGUs only. Therefore, the relevant scenarios to
examine were (1) SO2 and NOX emissions from all
EGUs nationwide after the application of BART controls to all BART-
eligible EGUs (``nationwide BART''), and (2) SO2 and
NOX emissions from all EGUs nationwide after the emissions
reductions attributable to CAIR in the CAIR region and application of
BART controls to all BART-eligible EGUS outside the CAIR region (``CAIR
+ BART''). The latter scenario reflects the fact that source-by-source
BART would remain a federal requirement outside the CAIR region, unless
and until it is replaced by some other state or federally required
program. Thus, in order to more accurately project CAIR emissions, it
is necessary to impose BART controls outside the CAIR region, to
account for potential load and emission shifting among EGUs.
In addition to these two scenarios, a third was used--the future
base case in the absence of either program. This third scenario was
used to ensure that CAIR would not cause degradation from otherwise
existing conditions. See section IV.B above for a discussion of why the
future baseline is an appropriate comparison point for the first prong
of the ``better than BART'' test.
At the SNPR stage, a ``CAIR + BART'' scenario was not available, as
the only projections available at that time had been developed for
other purposes. Thus, the ``CAIR'' scenario used then, which was based
on the Clear Skies proposal, was imperfect for purposes of this
analysis in that it assumed SO2 reductions on a nationwide
basis (rather than in the CAIR region only) and assumed NOX
reductions requirements in a slightly different geographic region than
covered by the proposed CAIR.
For the CAIR NFR, we redid the emissions projections for both the
Nationwide BART and CAIR + BART in the West scenarios. For the former,
we increased the number of BART-eligible units included by lowering the
assumed threshold for BART applicability from 250 MW capacity for both
NOX and SO2 to 100 MW for SO2 and 25
MW for NOX, and by reviewing the list of potentially BART-
eligible EGUs. For the latter scenario, we produced emissions
projections based on application of CAIR-level emission reductions in
the States proposed for inclusion in the CAIR in the SNPR.
Emission Projections. For the analyses in both the SNPR and NFR, we
used the Integrated Planning Model (IPM) to estimate emissions expected
from the scenarios described above. Tables 1 and 2 present the results
from the SNPR and NFR, respectively.
Table 1.--EGU SO2 and NOX Emissions--as Projected in CAIR SNPR
[In thousands of tons per year]
----------------------------------------------------------------------------------------------------------------
Additional
2015 Modeled reduction from
2015 Base case 2015 ``CAIR'' nationwide e ``CAIR''
EGU emissions Bart (nationwide BART
minus ``CAIR'')
----------------------------------------------------------------------------------------------------------------
Nationwide SO2.......................... 9,081 5,260 7,012 1,752
Nationwide NOX.......................... 3,950 2,248 2,781 533
----------------------------------------------------------------------------------------------------------------
Table 2.--EGU SO2 and NOX Emissions--as Projected in CAIR NFR
[In thousands of tons per year]
----------------------------------------------------------------------------------------------------------------
Additional
reduction from
2015 Base case 2015 CAIR + BART 2015 Nationwide CAIR + BART
EGU emissions BART (nationwide BART
minus CAIR+BART)
----------------------------------------------------------------------------------------------------------------
Nationwide SO2.......................... 9,084 4,735 7,162 2,427
Nationwide NOX.......................... 3,721 1,816 2,454 638
----------------------------------------------------------------------------------------------------------------
As can be seen in the numbers in the right-most column, CAIR
produced far superior emission reductions to nationwide BART, and the
superiority of CAIR over BART increased between the SNPR and NFR
projections, when the scenarios were corrected to more accurately
reflect the anticipated reality in 2015.
Air Quality Modeling Results. The proposed ``better-than-BART''
test provided that if the distribution of emission reductions is
substantially the same under the alternative program as under BART,
then the demonstration can be made simply by comparing emission
reductions. If, however, the distribution is significantly different,
[[Page 39140]]
then visibility modeling is required in order to apply the two pronged
test previously described. As noted above, CAIR emission reductions
were vastly greater than those under BART. However, because there were
some differences in the geographic distribution of reductions on a
state-by-state basis, in order to be conservative we conducted air
quality modeling and evaluated CAIR under the two pronged test.
Specifically, using the above emissions projections, we completed
numerous air quality modeling runs and postprocessing calculations to
determine the impacts of emissions and emissions control strategies on
visibility in Class I areas. We quantified the impacts of the CAIR and
BART controls on visibility impairment by comparing the results of the
future-year (2015) base case model runs with the results of the CAIR +
BART and nationwide BART control strategy model runs. We quantified
visibility impacts on the 20 percent best and 20 percent worst
visibility days.
For the SNPR modeling, we used the Regional Modeling System for
Aerosols and Deposition (REMSAD) model to calculate these visibility
impacts. This modeling used base year meteorology from 1996. Complete
year ambient monitoring data, which is necessary to model future
improvements in visibility, was available for 1996 from Inter-agency
Monitoring of Protected Visual Environments (IMPROVE) monitors located
at 44 Class I areas--13 within the CAIR region and 31 outside of it.
For the NFR modeling, we used the Community Multiscale Air Quality
(CMAQ) model. The base year meteorology used in the CMAQ modeling was
2001. This later base year enabled us to look at more Class I areas,
because there were more IMPROVE monitors which had complete year data
for 2001 than there had been in 1996. Specifically, 81 of the 110
IMPROVE sites have complete ambient air quality data for 2001.
Moreover, because in some cases a given IMPROVE monitor is designated
as representing more than one Class I area, these 81 sites are
representative of 116 Class I areas. Twenty nine of the 116 are in the
East (east of 100 degrees longitude) and 87 are in the West.
Using the modeling results, we then applied the two prong better
than BART test which had been defined in the proposed BART rule. As
explained above, under the first prong, visibility must not decline at
any Class I area, as determined by comparing the predicted visibility
impacts at each affected Class I area under the (CAIR) trading program
with future base case visibility conditions. Under the second prong,
overall visibility, as measured by the average improvement at all
affected Class I areas, must be better under the trading program than
under source-specific BART. The future year air quality modeling
results were used to make this demonstration.
The visibility impacts of the CAIR + BART scenario were compared to
base case 2015 visibility conditions (without CAIR or BART) to
determine whether the CAIR resulted in a degradation of visibility at
any Class I area. We also compared these visibility impacts with the
visibility impacts of nationwide BART implementation, to assess whether
the proposed CAIR would result in greater average visibility
improvement than nationwide BART.
The CAIR passed the first prong by not causing a degradation of
visibility at any Class I area, either in the West or nationally. This
was true in both the SNPR and NFR modeling. The visibility projections
for each Class I area are presented in the respective TSD's.\75\
---------------------------------------------------------------------------
\75\ See Footnote [74], Supra.
---------------------------------------------------------------------------
The overall results are presented in tables 3 and 4 below,
representing the SNPR and NFR modeling respectively.
Table 3.--Average Visibility Improvement in 2015 vs. 2015 Base Case (Deciviews) as Modeled Using REMSAD in CAIR
SNPR
----------------------------------------------------------------------------------------------------------------
``CAIR'' Scenario Nationwide BART
Class I areas ---------------------------------------------------------------
East \76\ National East National
----------------------------------------------------------------------------------------------------------------
20 percent Worst Days........................... 2.0 0.7 1.0 0.4
20 percent Best Days............................ 0.7 0.2 0.4 0.1
----------------------------------------------------------------------------------------------------------------
Table 4.--Average Visibility Improvement in 2015 vs. 2015 Base Case (Deciviews) as Modeled Using CMAQ in CAIR
NFR
----------------------------------------------------------------------------------------------------------------
CAIR + BART in West Nationwide BART
Class I Areas ---------------------------------------------------------------
East \76\ National East National
----------------------------------------------------------------------------------------------------------------
20 percent Worst Days........................... 1.6 0.5 0.7 0.2
20 percent Best Days............................ 0.4 0.1 0.2 0.1
----------------------------------------------------------------------------------------------------------------
As can be see from the tables, although the models produced
different absolute values, in both cases CAIR produced significantly
greater visibility improvement than nationwide BART. For example,
looking at the 20 percent worst days at Eastern Class I areas (the
areas most influenced by the CAIR, since it is an eastern program), in
both cases the visibility improvements from CAIR were at least twice as
great as under nationwide BART (i.e., in the SNPR, 2.0 deciviews
compared to 1.0 deciviews improvement, and in the NFR, 1.6 deciviews
compared to 0.7 deciviews improvement).
---------------------------------------------------------------------------
\76\ Eastern Class I areas are those in the CAIR affected
states, except areas in west Texas which are considered western and
therefore included in the national average, plus those in New
England
---------------------------------------------------------------------------
This historical overview is given in the interest of providing a
more complete understanding of the analyses presented at various stages
in the CAIR rule making progress. In the end, however, it is the
analyses presented in the CAIR NFR on which we are basing our
determination that CAIR makes greater reasonable progress towards the
national visibility goals than does nationwide BART. Therefore, these
NFR results are examined more closely in the ``Final Action'' section
below, in light of additional emissions projections we
[[Page 39141]]
have conducted to insure that changes to the CAIR and BART rules made
subsequent to the CAIR NFR do not affect that determination.
Comments Received and EPA's Responses
Although many comments were received regarding our proposal to
determine that CAIR makes greater reasonable progress than BART, nearly
all of them related either to the terms of the test itself, or to
policy and legal implications of allowing CAIR required reductions to
substitute for source-by-source BART. These are addressed in sections B
(above ) and D (below) respectively. One commenter asserted, with
respect to modeling presented in the SNPR, that the improvement of CAIR
compared to source-specific BART is so slight it may be potentially
within the margin of error, and therefore insufficient for the better
than BART demonstration, or for assuring that no hot spots will occur.
The EPA disagrees that the difference between CAIR and BART in the
SNPR visibility projections was not significant. The visibility results
presented in the NFR continue to show that the CAIR cap and trade
program with BART in the non-CAIR region provides considerably more
visibility improvement compared to nationwide BART (for EGUs only). The
NFR modeling results show that the average visibility improvement from
CAIR on the 20 percent worst days at 29 Eastern Class I areas is 1.6
deciviews (dv) compared to only a 0.7 dv improvement from nationwide
BART controls. In the ``better than BART'' TSD we have provided
modeling results for 116 individual Class I areas. The modeling shows
that CAIR will not create any ``hot spots.'' On the 20 percent worst
days, all of the Eastern Class I areas show more visibility improvement
under CAIR+BART than under BART alone. In many of the Western Class I
areas, nationwide BART and CAIR + BART in the West provide about the
same visibility benefits. (This is to be expected, since the CAIR is
only applicable in the East.) While the visibility benefits are similar
in the West (outside of the CAIR region), they are clearly not similar
in the East, where the CAIR is predicted to achieve twice as much
visibility improvement compared to BART.
Final action. The CAIR vs. BART comparison presented in the CAIR
NFR was developed while both rules were under development and therefore
subject to change. Since the emissions projections and air quality
modeling presented in the CAIR NFR was completed, several changes were,
in fact, made to the CAIR region. In addition, since that time our
assumptions regarding the likely maximum BART emission reductions from
EGUs also changed. Therefore, we recalculated the emission projections
to see if the rule changes could possibly affect the determination that
CAIR will achieve greater reasonable progress than BART.
Most significantly, the final CAIR included Arkansas, Delaware, and
New Jersey only for purposes of significant contribution to ozone non-
attainment by summertime NOX emissions, whereas our modeling
had been based on the assumption that these States would be included
for contribution to PM2.5 non-attainment by SO2
and NOX emissions. The new emission projections are based on
the application of CAIR only for ozone in these States.
With respect to the nationwide BART, for SO2 the NFR
projections assumed the application of a 90 percent control or 0.10
lbs/mmBtu at uncontrolled EGUs greater than 100 MW. In the new
projections, the control assumptions were changed to 95 percent or 0.15
lbs/mmbtu, to reflect the presumptive control levels in the final BART
guidelines. For NOX, the NFR projections were based on an
assumed emission rate of 0.2 lbs/mmBTU at all BART eligible EGUs
nationwide. The new projections are based on the assumption of
combustion controls on all BART eligible units except cyclones which
have SCR, and the operation of all existing SCR and SNCRs annually,
instead of just in the ozone season. Finally for both pollutants, the
threshold for application of controls was increased to 200 MW, to
better reflect the presumptions included in the final BART guidelines.
We used IPM to project 2015 emissions given these new parameters.
The results are presented in Table 5 below, which also includes the
CAIR NFR projections (as reported in Table 2) for the reader's
convenience.
Table 5.--EGU SO2 and NOX Emissions--as Projected in CAIR NFR and as Projected in Subsequent Update
(In thousands of tons per year)
----------------------------------------------------------------------------------------------------------------
Additional
reduction from
2015 CAIR + BART 2015 Nationwide CAIR + BART
BART (nationwide BART
minus CAIR+BART)
----------------------------------------------------------------------------------------------------------------
CAIR NFR:
Nationwide SO2........................................ 4,735 7,162 2,427
Nationwide NOX........................................ 1,816 2,454 638
Updated Projections:
Nationwide SO2........................................ 5,042 7,953 2,911
Nationwide NOX........................................ 2,000 2,738 738
----------------------------------------------------------------------------------------------------------------
The updated emissions estimates for both the BART and CAIR with
BART in the West scenarios are slightly higher than the NFR emissions
estimates, but the difference between the CAIR + BART and nationwide
BART scenarios are even larger compared to the NFR determination. For
SO2, the updated CAIR + BART achieves about 2.9 million tons
more reductions than updated nationwide BART in 2015. For
NOX, the updated CAIR + BART policy is projected to result
in about 738,000 tons more emissions reductions than the updated BART
nationwide policy in 2015. The difference between the updated CAIR +
BART and nationwide BART scenarios is now larger by 484,000 tons of
SO2 reduction (i.e., 2,911,000 - 2,427,000) and 100,000 tons
of NOX reduction (i.e. 738,000 - 638,000).
Implications of New Emission Projections for the Two-Pronged Test
The first prong of the better than BART test specifies that no
degradation of visibility can occur at any Class I area. In order to be
sure that Class I areas do not experience a degradation in
[[Page 39142]]
visibility, we examined the updated State by State emissions estimates.
Compared to the 2015 base case, in the updated CAIR + BART case, there
are no individual Statewide increases in either SO2 or
NOX (except for a very small 1,000 ton increase in
NOX in Connecticut and 2,000 ton increase in SO2
in New Jersey).\77\ That is consistent with the NFR CAIR + BART case in
which no degradation was found. Consequently we have determined that no
degradation would occur under the updated CAIR + BART emissions
scenario.
---------------------------------------------------------------------------
\77\ The 1,000 ton per year increase in NOX in
Connecticut represents approx. 0.003 percent of the total EGU
NOX in the 2015 base case and the 2,000 ton per year
increase in SO2 in New Jersey represents approx. 0.0005
percent of the total EGU SO2 . Since the impacts on
visibility from EGU SO2 and NOX are generally
regional in nature, we would expect this small increase to have
little or no impact on visibility in any Class I area.
---------------------------------------------------------------------------
The second prong of the better than BART test specifies a greater
average visibility improvement from the CAIR trading program (CAIR +
BART). The average visibility improvement from the NFR CAIR + BART case
was much greater (on the 20 percent worst visibility days) than the
nationwide BART case. In the scenario we modeled for the NFR, the
larger visibility improvement from CAIR + BART was achieved by reducing
SO2 emissions by an additional 2.4 million tons per year
compared to nationwide BART and NOX emissions by an
additional 638,000 tons per year compared to natiowide BART.
In the updated scenario, the emissions difference between the CAIR
+ BART and nationwide BART cases are even larger (2.9 million tons of
SO2 and 738,000 tons of NOX).\78\ The
distribution of emission reductions changed somewhat in the new
projections--that is, some States saw a larger difference between CAIR
and BART, while in other States the difference was smaller. The largest
change was in Kentucky, where the new projections showed that emission
reductions from CAIR were even greater than those from BART by an
additional 200,000 tons per year. Among States where the change between
projections went the other direction--that is, showing that BART
reductions were closer to CAIR reductions than previously projected--
the greatest changes were in Alabama and Pennsylvania, where the
difference between the programs decreased by 46,000 and 45,000 tons,
respectively.
---------------------------------------------------------------------------
\78\ The difference between the updated CAIR + BART and
nationwide BART scenarios is larger than the difference between the
modeled CAIR + BART and nationwide BART scenarios. The ``difference
of the differences'' is 485,000 tons of SO2 and 100,000
tons of NOX.
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Perhaps more importantly, in the new projections, there are fewer
States in which BART reductions are greater than CAIR reductions. In
the NFR projections, there were 12 States \79\ where nationwide BART
SO2 reductions were greater than CAIR + BART reductions.\80\
In those 12 States, BART emissions achieved approx. 686,000 more tons
of SO2 reduction compared to CAIR + BART. In the rest of the
States, CAIR + BART achieved an additional 3.1 million tons per year of
SO2 reduction compared to BART. All told, the modeling
showed that visibility improvement was greater under the CAIR than
under BART on an overall average basis, both at eastern Class I areas
and at all Class I areas nationally. In the new projections, CAIR +
BART achieved an additional 3.4 million tons per year of SO2
reduction compared to BART in 39 of the 48 States. In the remaining 9
States \81\ BART achieved approx. 472,000 more tons of SO2
reduction compared to CAIR + BART in the west.\82\
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\79\ California, Delaware, Florida, Georgia, Iowa, Louisiana,
Michigan, Mississippi, Missouri, North Carolina, Texas, and
Wisconsin.
\80\ There were also four States where BART NOX
emissions reductions were slightly higher than CAIR + BART (a total
of 4,000 tons per year). Those States are Connecticut, Delaware, New
Jersey, and Oklahoma.
\81\ Alabama, Louisiana, Michigan, Mississippi, Missouri, New
Jersey, North Carolina, Texas, Wisconsin.
\82\ We performed a similar analysis using projections including
the Clean Air Mercury Rule, CAMR, which was promulgated after the
CAIR NFR. The CAMR emission projections show slight additional
emission reductions of SO2 and NOX as compared
to the projections CAIR + BART without CAMR, and are nearly
identical in terms of geographic distribution. Therefore CAIR + BART
+ CAMR, like CAIR + BART, passes the two-pronged test for
demonstrating greater reasonable progress than BART. This is
discussed in more detail in the TSD accompanying today's action.
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Due to the fact that the new projections show that the difference
between CAIR and BART reductions is even greater than previously
estimated, and the visibility improvements due to CAIR + BART were
previously modeled to be much larger than BART, we can state with a
high degree of confidence that the updated CAIR + BART scenario passes
the second prong of the better than BART test.
D. Revision to Regional Haze Rule To Allow CAIR States To Treat CAIR as
a BART-Substitute for EGUs
In the SNPR, we proposed that States which adopt the CAIR cap and
trade program for SO2 and NOX would be allowed to
treat the participation of EGUs in this program as a substitute for the
application of BART controls for these pollutants at affected EGUs. To
implement this, we proposed an amendment to the Regional Haze Rule
which would add a subpart 40 CFR 51.308(e)to read as follows:
A State that opts to participate in the Clean Air Interstate
Rule cap-and-trade program under part 96 AAA-EEE need not require
affected BART-eligible EGUs to install, operate, and maintain BART.
A State that chooses this option may also include provisions for a
geographic enhancement to the program to address the requirement
under Sec. 51.302(c) related to BART for reasonably attributable
impairment from the pollutants covered by the CAIR cap and trade
program.\83\
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\83\ A geographic enhancement is a method, procedure, or process
to allow a broad regional strategy, such as the CAIR cap & trade
program, to accommodate BART for reasonably attributable impairment.
For example, it could consist of a methodology for adjusting
allowance allocations at a source which is required to install BART
controls.
We proposed that this would be codified at 40 CFR 51.308(e)(3);
however, that section now incorporates the ``better than BART'' test as
discussed above. In today's action, as described below we are
finalizing this provision of the rule, where it will be codified as
section 308(e)(4).
The EPA's authority to treat emissions reductions required by the
CAIR as satisfying BART was not affected by CEED. As noted, the D.C.
Circuit in CEED upheld the proposition that EPA can approve
implementation plans which rely on alternative strategies to BART, as
long as greater reasonable progress is achieved. CEED, 398 F.3d at 660.
Moreover, the CAIR program is not infected in any way with the ``group
BART'' methodology held invalid by the court. That is because CAIR
emission reductions levels were not based on the invalid ``group-BART''
approach or any other assumptions regarding BART, but were developed
for other reasons. Specifically, the CAIR was developed to assist with
attainment of the NAAQS for PM2.5 and ozone. Had EPA not
performed the comparison of CAIR to BART for visibility progress
purposes, the CAIR emission reduction requirements would remain
unchanged. Therefore, EPA is not imposing an invalid BART requirement
on States, but rather allowing States, at their option, to utilize the
CAIR cap and trade program as a means to satisfy BART for affected
EGUs.
We received numerous comments on this proposal, which are
summarized along with our responses in the CAIR NFR preamble at 70 FR
25300-25302 and in the Response to Comment document. To summarize our
responses to some of the most important comments:
[[Page 39143]]
(1) We note that we are not constraining the discretion of States
to determine which sources are subject to BART and to make BART
determinations. CAIR-affected States are not required to accept our
determination that CAIR may substitute for BART. Under the amended
rule, States simply have the option of accepting this determination.
(2) The EPA does not believe that anything in the CAA or relevant
case law prohibits a State from considering emissions reductions
required to meet other CAA requirements when determining whether source
by source BART controls are necessary to make reasonable progress.
Whatever the origin of the emission reduction requirement, the relevant
question for BART purposes is whether the alternative program makes
greater reasonable progress. As discussed above, EPA has determined
that CAIR does so with respect to SO2 and NOX
from EGUs in the CAIR region.
Moreover, the fact that BART and CAIR originate from different
provisions of the CAA does not mean that CAIR and BART emissions
reductions would be additive if BART-eligible EGUs in the CAIR program
were required to install and operate BART. Such source specific control
requirements would simply result in a redistribution of emission
reductions, as other EGUs could buy the excess allowances generated by
the installation of controls at BART units. The net result would be the
same level of emission reductions, but at a higher total cost, because
the ability of the market to find the most cost effective emission
reductions would be constrained.
(3) Although regional haze rule section 308(e)(2) is not directly
applicable, as the CAIR is covered by the special provision newly
codified at section 308(e)(4), this determination is consistent with
the policy contained in section 308(e)(2) requiring in-lieu of BART
programs be based on emissions reductions ``surplus to reductions
resulting from measures adopted to meet requirements as of the baseline
date of the SIP.'' The baseline date for regional haze SIPs is
2002;\84\ therefore CAIR reductions are surplus to requirements as of
that year.
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\84\ See Memorandum from Lydia Wegman and Peter Tsirigotis, 2002
Base Year Emission Inventory SIP Planning: 8-hr Ozone, PM2.5, and
Regional Haze Programs, November 8, 2002. http://www.epa.gov/ttn/oarpg/t1/ memoranda/2002bye--gm.pdf.
---------------------------------------------------------------------------
(4) We agree with commenters that it was premature to make a final
determination whether CAIR makes greater reasonable progress than BART
in the final CAIR because at that time the BART guidelines and the
criteria for making such determinations had not been finalized. In
today's action, both those rule makings are complete and therefore such
a determination is ripe.
(5) We disagree with commenters who thought that CAIR should be
considered ``better than BART'' regardless of whether a State
participates in the cap and trade program. Our demonstration that CAIR
makes greater reasonable progress than BART is based only on an
examination of emissions reductions from EGUs under both programs. The
CAIR emissions projections and modeling assumes that EGU emissions will
be capped at the levels specified in the CAIR. Therefore, States that
choose to meet their CAIR emission reduction requirements in a manner
other than through the participation of EGUs in the CAIR cap and trade
program would have to develop an appropriate demonstration that the
measures they employ make greater reasonable progress than would BART
for any affected source categories, if the State wanted its CAIR-
required reductions to substitute for source-by-source BART.
(6) We disagree with commenters who asserted that CAIR should
satisfy BART for States that are subject to CAIR only for ozone season
NOX. We explained in the final CAIR preamble that a State
subject to CAIR for NOX purposes only would have to make a
supplementary demonstration that BART has been satisfied for
SO2, as well as for NOX on an annual basis. We
wish to clarify here that a State which is only subject to CAIR for
NOX, but which also chooses to participate in the CAIR
trading program for both SO2 and NOX, may
consider BART to be satisfied for both SO2 and
NOX from EGUs. Because we modeled these States as
controlling for both SO2 and NOX in the CAIR NFR,
our better than BART demonstration presented in that action would be
valid in that scenario. Conversely, if such States choose to
participate only in the ozone season NOX trading program,
the updated projections presented in today's action demonstrate that
BART would be satisfied for NOX, but such states would still
need to address BART for SO2 emissions from EGUs.
(7) We noted in the final CAIR preamble that although we believe it
is unlikely that a State or FLM will find it necessary to certify
reasonably attributable visibility impairment at any Class I area, as a
legal matter that possibility exists. That is, the determination that
CAIR makes greater reasonable progress than BART is made in the context
of BART for regional haze under CAA 169B, and does not preclude a
finding of reasonably attributable impairment under CAA 169A. The CAIR
cap and trade program does not include geographic enhancements to
accommodate the situation where BART is required based on reasonable
attribution at a source which participates in the trading program, but
States retain the discretion to include such enhancements in their
SIPs.
(8) Our determination that CAIR makes greater reasonable progress
than BART for EGUs is not a determination that CAIR satisfies all
reasonable progress requirements in CAIR affected States. Each State,
whether in the CAIR region or not, is required to set reasonable
progress goals for each Class I area within the State as required in
regional haze rule section 308(d)(1), and to develop long term
strategies, considering all anthropogenic sources of visibility
impairing pollutants, as required by section 308(d)(3).
In setting the reasonable progress goals, the State is to consider
the amount of visibility improvement needed to achieve a uniform rate
of progress towards natural background conditions in the year 2064.
(This uniform rate of progress is sometimes referred to as the default
glide-path). The State is also to consider the statutory reasonable
progress factors contained in CAA section 169A(g)(1).\85\
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\85\ Similar to the BART factors, the reasonable progress
factors are: the cost of compliance, the time necessary for
compliance, the energy and nonair quality environmental impacts of
compliance, and the remaining useful life of any existing sources
subject to such requirements.
---------------------------------------------------------------------------
In doing so, we anticipate that States will take into account the
degree to which CAIR emissions reductions are projected to bring
visibility conditions at its Class I areas in line with the default
glide path. In some States, the improvements expected from CAIR,
combined with the application of the reasonable progress factors to
other source sectors, may result in a determination that few additional
emissions reductions are reasonable for the first long term strategy
period. Nonetheless, each State is required to set its reasonable
progress goals as provided by the regional haze rule and cannot assume
that CAIR will satisfy all of its visibility-related obligations.
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA
must determine whether the regulatory action is ``significant'' and,
therefore, subject to Office of Management and Budget
[[Page 39144]]
(OMB) review and the requirements of the Executive Order. The Order
defines ``significant regulatory action'' as one that is likely to
result in a rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or Tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
(3) Materially alter the budgetary impacts of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
Pursuant to the terms of Executive Order 12866, it has been
determined that this rule is a ``significant regulatory action,'' thus
EPA has submitted this rule to OMB for review. The drafts of the rules
submitted to OMB, the documents accompanying such drafts, written
comments thereon, written responses by EPA, and identification of the
changes made in response to OMB suggestions or recommendations are
available for public inspection at EPA's Air and Radiation Docket and
Information Center (Docket Number OAR-2002-0076). The EPA has prepared
the document entitled ``Regulatory Impact Analysis of the Final Clean
Visibility Interstate Rule or Guidelines for Best Available Retrofit
Technology Determinations Under the Regional Haze Regulations'' (RIA)
to address the requirements of this executive order.
1. What Economic Analyses Were Conducted for the Rulemaking?
The analyses conducted for this final rule provide several
important analyses of impacts on public welfare. These include an
analysis of the social benefits, social costs, and net benefits of
three possible regulatory scenarios that States may follow to implement
the BART rule and guidelines. The economic analyses also address issues
involving requirements of the Paperwork Reduction Act (PRA), potential
small business impacts, unfunded mandates (including impacts for Tribal
governments), environmental justice, children's health, energy impacts,
and other statutory and executive order requirements.
2. What Are the Benefits and Costs of This Rule?
The benefit-cost analysis shows that substantial net economic
benefits to society are likely to be achieved due to reductions in
emissions resulting from this rule. The results detailed below show
that this rule would be beneficial to society, with annual net benefits
(benefits less costs) ranging from approximately $1.9 to $12.0 billion
in 2015. These alternative net benefits estimates reflect differing
assumptions about State actions taken to implement BART and about the
social discount rate used to estimate the annual value of the benefits
and costs of the rule. All amounts are reflected in 1999 dollars. The
range of benefits and costs reported for the BART represent estimates
of EPA's assessment of State actions that will likely be taken to
comply with the BART rule and guidelines.
a. Control Scenarios
Today's rule sets forth presumptive requirements for States to
require EGUs to reduce SO2 and NOX emissions for
units greater than 200 megawatts (MW) in capacity at plants greater
than 750 MW in capacity that significantly contribute to visibility
impairment in Federal Class I areas (national parks). The analysis
conducted in the RIA presents alternative control scenarios of possible
additional controls for EGUs located at plants less than 750 MW in
capacity. The EPA also calculated the amount of SO2 and
NOX emissions reductions for several illustrative scenarios
that reflect alternative State actions regulating industries with non-
EGU sources. The analyses conducted include three regulatory
alternative scenarios that States may choose to follow to comply with
BART. The alternatives include three scenarios of increasing
stringency--Scenario 1, Scenario 2, and Scenario 3. A brief discussion
of the these alternatives for the EGUs and all other sources follows.
More details of the alternative control scenarios and associated
control costs are discussed in the RIA.
i. Electric Generating Units
In the revised BART guidelines, we have included presumptive
control levels for SO2 and NOX emissions from
coal-fired electric generating units greater than 200 megawatts (MW) in
capacity at plants greater than 750 MW in capacity. Given the
similarities of these units to other BART-eligible coal-fired units
greater than 200 MW at plants 750 MW or less, EPA's guidance suggests
that States control such units at similar levels for BART. The
guidelines would require 750 MW power plants to meet specific control
levels of either 95 percent control or controls of 0.15 lbs/MMBtu, for
each EGU greater than 200 MW, unless the State determines that an
alternative control level is justified based on a careful consideration
of the statutory factors.\86\ Thus, for example, if the source
convincingly demonstrates unique circumstances affecting its ability to
cost-effectively reduce its emissions, the State may take that into
account in determining whether the presumptive levels of control are
appropriate for the facility. For an EGU greater than 200 MW in size,
but located at a power plant smaller than 750 MW in size, States may
also find that such controls are cost-effective when taking into
consideration the costs of compliance in the BART analysis in applying
the five factor test for the BART determination. In our analysis we
have assumed that no additional controls will occur where units have
existing scrubbers and that no controls will occur for oil-fired units.
While these levels may represent current control capabilities, we
expect that scrubber technology will continue to improve and control
costs will continue to decline.
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\86\ These levels are commonly achievable by flue gas
desulfurization controls (``scrubbers'').
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For NOX, for those large EGUs that have already
installed selective catalytic reduction (SCR) or selective non-
catalytic reduction (SNCR) during the ozone season, States should
require the same controls for BART. However, those controls should be
required to operate year-round for BART. For sources currently using
SCR or SNCR for part of the year, states should presume that the use of
those same controls year-round is highly cost-effective. For other
sources, the guidelines establish presumptive emission levels that vary
depending largely upon boiler type and fuel burned. For coal-fired
cyclone units with a size greater than 200 MW, our analysis assumes
these units will install SCR. For all other coal-fired units, our
analysis assumed these units will install current combustion control
technology. In addition, we assume no additional controls for oil and/
or gas-fired steam units.
We present alternative regulatory scenarios. Scenario 2 represents
our application of the presumptive limits described above to all BART
eligibility EGUs greater than 200 MW. For Scenario 1, we assume that
only 200 MW BART-eligible EGUs located at facilities above 750 MW
capacity will comply with the SO2 requirements and
NOX controls. In this scenario, no
[[Page 39145]]
facilities less than 750 MW capacity are assumed to install BART
controls. For Scenario 1, we assume that units with existing SCRs will
operate those SCR units year round annually. In contrast in Scenario 3,
we analyzed SO2 controls equivalent to 95 percent reductions
or 0.1 lbs per MMBtu on all previously uncontrolled units.
NOX controls for this most stringent scenario presume SCRs
will be installed on all units greater than 100 MW capacity and
combustion controls will be installed on units greater than 25 MW but
less than 100 MW capacity. The EPA analyzed the costs of each BART
scenario using the Integrated Planning Model (IPM). The EPA has used
this model extensively in past rulemakings to analyze the impacts of
regulations on the power sector.
The analysis presented assumes that BART-eligible EGUs affected by
the Clean Air Interstate Rule (70 FR 25162) have met the requirements
of this rule. Thus, no additional controls for EGUs beyond CAIR are
anticipated or modeled for the 28 State plus District of Columbia CAIR
region. In addition, we are assuming no additional SO2
controls for sources located in States of Arizona, Utah, Oregon,
Wyoming, and New Mexico or Tribal lands located in these States due to
agreements made with the Western Regional Air Partnership (WRAP).
ii. Sources Other Than Electric Generating Units
As previously discussed there are 25 source categories potentially
subject to BART in addition to EGUs (referred to as non-EGU source
categories) as defined by the CAA. The EPA evaluated a set of
SO2 and NOX emission control technologies
available for these source categories and estimated the associated
costs of control using AirControlNET. The control scenarios evaluated
reflect control measure cost caps of up to $1,000 per ton (Scenario 1),
$4,000 per ton (Scenario 2), and $10,000 per ton (Scenario 3). The EPA
also conducted a cost analysis for control costs of up to $2,000 per
ton and $3,000 per ton, and the results of this analysis are presented
in the RIA. The analysis consists of applying SO2 and
NOX controls to each non-EGU source category up to the
specified cost per ton ``cap'' in each scenario. These cost per ton
caps are specified in average cost terms. As control stringency is
increased, the marginal costs are also estimated for each non-EGU
source category. The scenarios examined are based on the costs of
technologies such as scrubbers for SO2 control, and varying
types of technologies for NOX control. Scrubbers are the
most common type of SO2 control for most non-EGU sources for
each scenario, while combustion controls such as low NOX
burners (LNB) and post-combustion controls such as selective
noncatalytic reduction (SNCR) and selective catalytic reduction (SCR)
are commonly applicable to most of the non-EGU source categories.
Combustion controls are commonly applied as part of Scenario 1, while
SNCR and SCR are more commonly applied either by themselves or in
combination with combustion controls as part of Scenarios 2 and 3.
Analyses are not available for 8 of the 25 non-EGU source categories,
because there are no available control measures for these sources or
there are no sources in these categories included in the non-EGU
emissions data utilized in these analyses. All of these results are
estimated using a nationwide database of BART-eligible non-EGU sources
that is based on information collected from Regional Planning
Organizations (RPOs) in the fall of 2004.
b. Baseline and Year of Analysis
The final rule sets forth the guidelines for States and Tribes for
meeting the BART requirements under the CAA and the Regional Haze Rule.
The Agency considered all promulgated CAA requirements and known State
actions in the baseline used to develop the estimates of benefits and
costs for this rule including the recently promulgated Clean Air
Interstate Rule (70 FR 25162) and the proposal to include New Jersey
and Delaware in the final CAIR region for fine particulate matter (70
FR 25408). However, EPA did not include within the baseline the actions
States may take to implement the ozone and PM2.5 NAAQS
standards nor the recently promulgated Clean Air Mercury Rule. No
additional SO2 controls were assumed for any EGUs within the
five WRAP States of Utah, Arizona, Wyoming, Oregon or New Mexico that
have existing agreements to achieve reduction goals.
In the analysis, the controls and reductions are assumed to be
required in 2015, a date that is generally consistent with the expected
timing of the rule. States must submit SIPs relevant to the BART
requirements in January 2008. After approval of the SIP, there is a 5
year compliance date. Thus, controls are likely to be installed and in
operation by the end of 2013 or the beginning of 2014 to comply with
the rule. In addition, EPA had existing inventories, modeling, and base
case runs for 2015 to use for the analysis. The year 2015 is used in
this analysis. All estimates presented in this report represent
annualized estimates of the benefits and costs of BART in 2015 rather
than the net present value of a stream of benefits and costs in these
particular years of analysis.
c. Cost Analysis and Economic Impacts
For the affected region, the projected annual private incremental
costs of BART to the power industry (EGU source category) range from
$253 to $896 million in 2015 depending upon the scenario evaluated.
These costs represent the private compliance cost to the electric
generating industry of reducing NOX and SO2
emissions that EPA believes States may require to comply with BART.
In estimating the net benefits of regulation, the appropriate cost
measure is ``social costs.'' Social costs represent the welfare costs
of the rule to society. These costs do not consider transfer payments
(such as taxes) that are simply redistributions of wealth. The social
costs of this rule for the EGU sector only are estimated to range from
approximately $119 to $567 million in 2015 assuming a 3 percent
discount rate. These EGU sector costs become $141 to $688 million in
2015 assuming a 7 percent discount rate.
Overall, the impacts of the BART are modest, particularly in light
of the large benefits we expect. Retail electricity prices are
projected to increase roughly 0.1 percent with BART in the 2015
timeframe under Scenario 2. Coal-fired generation, as well as coal
production and natural gas-fired generation are projected to remain
essentially unchanged as a result of this rule. It is also not expected
that BART will change the composition of new generation built to meet
growth in electricity demand. BART is also not expected to impact coal
or natural gas prices.
For today's rule, EPA analyzed the costs for the EGU source
category using the Integrated Planning Model (IPM). The IPM is a
dynamic linear programming model that can be used to examine the
economic impacts of air pollution control policies for SO2
and NOX throughout the contiguous U.S. for the entire power
system. Documentation for IPM can be found in the docket for this
rulemaking or at http://www.epa.gov/airmarkets/epa-ipm.
The EPA also conducted an analysis of State actions in requiring
emission controls for BART eligible sources in the non-EGU source
categories. For the nation, the projected annual private incremental
costs range from $150 million to $2.24 billion for industries with
affected non-EGU sources. This cost range results from different
assumptions about possible actions
[[Page 39146]]
States may take to comply with BART and alternative discount rates of 3
and 7 percent. The non-EGU private incremental control cost estimates
are assumed to approximate the social costs of the rule for the non-EGU
sector. The EPA analyzed the costs to non-EGUs sources using
AirControlNET. The AirControlNET is a software tool that can be used to
estimate the private costs and emission reductions of air pollution
control policies for SO2, NOX, and other criteria
pollutants throughout the contiguous U.S. for all manufacturing
industries and many other industries. Documentation for AirControlNET
can be found in the docket for this rulemaking or at http://www.epa.gov/ttn/ecas/AirControlNET.htm.
In summary, the EPA estimates that the annual social costs of this
rule for the EGU and non-EGU source categories range from approximately
$0.3 to $2.9 billion annually, based on alternative scenarios of State
actions in response to the BART rule and guidelines assuming 3 or 7
percent discount rates. Estimates are reflected in 1999 dollars.
d. Human Health Benefit Analysis
Our analysis of the health and welfare benefits associated with
this rule are presented in this section. Briefly, the analysis projects
major benefits from implementation of the rule in 2015. As described
below, thousands of deaths and other serious health effects would be
prevented. We are able to monetize annual benefits ranging from
approximately $2.2 to $14.3 billion in 2015. This range reflects
different assumptions about States actions in response to the BART rule
and the applicable discount rate (3 percent or 7 percent).
Table IV-1 presents the primary estimates of reduced incidence of
PM- and visibility-related health effects for 2015 for the regulatory
control strategy the EPA expects States may follow to comply with BART.
In 2015 for Scenario 2, we estimate that PM-related annual benefits
include approximately 1,600 fewer premature fatalities, 890 fewer cases
of chronic bronchitis, 2,200 fewer non-fatal heart attacks, 2300 fewer
hospitalizations (for respiratory and cardiovascular disease combined--
admissions and emergency room visits) and result in significant
reductions in days of restricted activity due to respiratory illness
(with an estimate of one million fewer cases) and approximately 170,000
fewer work-loss days. We also estimate substantial health improvements
for children from reduced upper and lower respiratory illness, acute
bronchitis, and asthma attacks.
Ozone health-related benefits are expected to occur during the
summer ozone season (usually ranging from May to September in the
Eastern U.S.). Since we did not conduct ozone modeling for this
rulemaking, we are unable to quantify or monetize the ozone related
benefits that will likely result from BART.
Table IV-2 presents the estimated monetary value of reductions in
the incidence of health and welfare effects. Annual PM-related health
benefits and visibility benefits are estimated to range from
approximately $2.2 to $14.3 billion annually. This range of estimates
reflects different scenarios about States actions in response to the
BART rule and the applicable discount rate (3 percent or 7 percent).
Estimated annual visibility benefits in southeastern and southwestern
Class I areas range from approximately $80 million to $420 million
annually in 2015. All monetized estimates are stated in 1999$. These
estimates account for growth in real gross domestic product (GDP) per
capita between the present and 2015. As the table indicates, total
benefits are driven primarily by the reduction in premature fatalities
each year. Reductions in premature mortality account for over 90
percent of total benefits.
Table IV-3 presents the total monetized net benefits for 2015. This
table also indicates with a ``B'' those additional health and
environmental benefits of the rule that we were unable to quantify or
monetize. These effects are additive to the estimate of total benefits.
A listing of the benefit categories that could not be quantified or
monetized in our benefit estimates are provided in Table IV-4. We are
not able to estimate the magnitude of these unquantified and
unmonetized benefits. While EPA believes there is considerable value to
the public for the PM-related benefit categories that could not be
monetized, we believe these benefits may be small relative to those
categories we were able to quantify and monetize. In contrast, EPA
believes the monetary value of the ozone-related premature mortality
benefits could be substantial, but we were unable to estimate the
benefits for this rulemaking.
e. Quantified and Monetized Welfare Benefits
Only a subset of the expected visibility benefits--those for Class
I areas in the southeastern and southwestern U.S. are included in the
monetary benefits estimates we project for this rule. We believe the
benefits associated with these non-health benefit categories are likely
significant. For example, we are able to quantify significant
visibility improvements in Class I areas in the Northeast and Midwest,
but are unable at present to place a monetary value on these
improvements. Similarly, we anticipate improvement in visibility in
residential areas where people live, work and recreate in the nation
for which we are currently unable to monetize benefits. For the Class I
areas in the southeastern and southwestern U.S., we estimate annual
benefits ranging from $80 to $420 million beginning in 2015 for
visibility improvements. The value of visibility benefits in areas
where we were unable to monetize benefits could also be substantial.
Table IV-1.--Clean Air Visibility Rule: Estimated Reduction in Incidence of Adverse Health Effects in 2015 \a,b\
----------------------------------------------------------------------------------------------------------------
Incidence reduction
Health Effect -----------------------------------------------------
Scenario 1 Scenario 2 Scenario 3
----------------------------------------------------------------------------------------------------------------
PM-Related Endpoints:
Premature mortality \c\
Adult, age 30 and over............................ 400 1,600 2,300
Infant, age <1 year............................... 1 4 5
Chronic bronchitis (adult, age 26 and over)........... 230 890 1,300
Non-fatal myocardial infarction (adults, age 18 and 570 2,200 3,000
older)...............................................
Hospital admissions--respiratory (all ages) \d\....... 140 510 720
Hospital admissions--cardiovascular (adults, age >18) 120 450 640
\e\..................................................
Emergency room visits for asthma (age 18 years and 370 1,300 1,800
younger).............................................
Acute bronchitis (children, age 8-12)................. 550 2,100 3,000
[[Page 39147]]
Lower respiratory symptoms (children, age 7-14)....... 6,600 25,000 36,000
Upper respiratory symptoms (asthmatic children, age 9- 5,000 19,000 27,000
18)..................................................
Asthma exacerbation (asthmatic children, age 6-18).... 8,100 31,000 44,000
Work loss days (adults, age 18-65).................... 44,000 170,000 240,000
Minor restricted-activity days (MRADs) (adult age, 18- 260,000 1,000,000 1,400,000
65)..................................................
----------------------------------------------------------------------------------------------------------------
\a\ Incidences are rounded to two significant digits. These estimates represent benefits from BART nationwide.
The modeling used to derive these incidence estimates assumes the final CAIR program in the baseline including
the CAIR promulgated rule and the proposal to include SO2 and annual NOX controls for New Jersey and Delaware.
Modeling used to develop these estimates assumes annual SO2 and NOX controls for Arkansas for CAIR resulting
in a slight understatement of the reported benefits and costs for BART. The recently promulgated CAMR has not
been considered in the baseline for BART.
\b\ Ozone benefits are expected for BART, but are not estimated for this analysis.
\c\ Adult premature mortality based upon studies by Pope et al., 2002. Infant premature mortality is based upon
studies by Woodruff, Grillo, and Schoendorf, 1997.
\d\ Respiratory hospital admissions for PM include admissions for chronic obstructive pulmonary disease (COPD),
pneumonia, and asthma.
\e\ Cardiovascular hospital admissions for PM include total cardiovascular and subcategories for ischemic heart
disease, dysrhythmias, and heart failure.
Table IV-2. Estimated Monetary Value of Reductions in Incidence of Health and Welfare Effects for the Clean Air
Visibility Rule in 2015
[In millions of 1999$] a,b
----------------------------------------------------------------------------------------------------------------
Scenario 1 Scenario 2 Scenario 3
----------------------------------------------------------------------------------------------------------------
Health Effects:
Premature mortality c,d
Adult >30 years
3 percent discount rate.................... $2,330 $9,180 $13,000
7 percent discount rate.................... 1,960 7,730 10,900
Infant <1 year................................. 6.12 23.8 34.2
Chronic bronchitis (adults, 26 and over)........... 90.5 353 498
Nonfatal acute myocardial infarctions
3 percent discount rate........................ 49.3 189 264
7 percent discount rate........................ 45.8 175 245
Hospital admissions for respiratory causes......... 1.07 4.03 5.65
Hospital admissions for cardiovascular causes...... 2.6 10.0 14.1
Acute bronchitis (children, age 8-12).............. 0.207 0.79 1.12
Lower respiratory symptoms (children, 7-14)........ 0.109 0.415 0.587
Upper respiratory symptoms (asthma, 9-11).......... 0.137 0.523 0.74
Emergency Room Visits for Asthma (age 18 years and 0.106 0.362 0.51
younger)..........................................
Asthma exacerbations............................... 0.367 1.4 1.98
Work loss days..................................... 5.56 22.4 31.5
Minor restricted-activity days (MRADs)............. 13.8 54.1 76.3
Welfare Effects:
Recreational visibility, 81 Class I areas.......... 84 239 416
--------------------
Monetized Total \e\
Base Estimate:
3 percent discount rate.................... 2,600+B 10,100+B 14,300+B
7 percent discount rate.................... 2,200+B 8,600+B 12,200+B
----------------------------------------------------------------------------------------------------------------
\a\ Monetary benefits are rounded to three significant digits. These estimates are nationwide with the exception
of visibility benefits. Visibility benefits relate to Class I areas in the southeastern and southwestern
United States. Ozone benefits are expected for BART, but have not been estimated for this analysis. The
benefit estimates assume the final CAIR program in the baseline that includes the CAIR promulgated rule and
the proposal to include SO2 and annual NOX controls for New Jersey and Delaware. Modeling used to develop the
CAIR baseline estimates assumes annual SO2 and NOX controls for Arkansas resulting in a slight understatement
of the reported benefits and costs for BART. The recently promulgated CAMR is not considered in the baseline
for BART.
\b\ Monetary benefits adjusted to account for growth in real GDP per capita between 1990 and the analysis year
of 2015.
\c\ Valuation assumes discounting over the SAB-recommended 20-year segmented lag structure described in Chapter
4. Results show 3 percent and 7 percent discount rates consistent with EPA and OMB guidelines for preparing
economic analyses (U.S. EPA, 2000; OMB, 2003).
\d\ Adult premature mortality based upon studies by Pope et al., 2002. Infant premature mortality based upon
studies by Woodruff, Grillo, and Schoendorf, 1997.
\e\ B represents the monetary value of health and welfare benefits not monetized. A detailed listing is provided
in Table IV-4. Totals rounded to nearest $100 million, and totals may not sum due to rounding.
Table IV-3.--Summary of Annual Benefits, Costs, and Net Benefits of the Clean Air Visibility Rule in 2015 a
[Billions of 1999$]
----------------------------------------------------------------------------------------------------------------
Description Scenario 1 Scenario 2 Scenario 3
----------------------------------------------------------------------------------------------------------------
Social costs b
[[Page 39148]]
3 percent discount rate..................................... $0.4 $1.4 $2.3
7 percent discount rate..................................... 0.3 1.5 2.9
Social benefits c, d, e
3 percent discount rate..................................... 2.6 + B 10.1 + B 14.3 + B
7 percent discount rate..................................... 2.2 + B 8.6 + B 12.2 + B
Health-related benefits:
3 percent discount rate..................................... 2.5 9.8 13.9
7 percent discount rate..................................... 2.1 8.4 11.8
Visibility benefits............................................. 0.08 0.24 0.42
Net benefits (benefits-costs) e, f
3 percent discount rate..................................... 2.2 + B 8.7 + B 12.0 + B
7 percent discount rate..................................... 1.9 + B 7.1 + B 9.3 + B
----------------------------------------------------------------------------------------------------------------
a All estimates are rounded to three significant digits and represent annualized benefits and costs anticipated
for the year 2015. Estimates assume a complete CAIR program in the baseline including the CAIR promulgated
rule and the proposal to include SO2 and annual NOX controls for New Jersey and Delaware. Modeling used to
develop the CAIR baseline estimates assumes annual SO2 and NOX controls for Arkansas resulting in a slight
understatement of the reported benefits and costs for BART. The recently promulgated CAMR is not considered in
the baseline for BART.
b Note that costs are the annualized total costs of reducing pollutants including NOX and SO2 for the EGU source
category in areas outside the CAIR region and excluding additional SO2 controls for the WRAP 309 States of UT,
AZ, WY, OR or NM and include costs for non-EGU sources nationwide. The discount rate used to conduct the
analysis impacts the control strategies chosen for the non-EGU source category resulting in greater level of
controls under the 3 percent discount rate for Scenario 1.
c As this table indicates, total benefits are driven primarily by PM-related health benefits. The reduction in
premature fatalities each year accounts for over 90 percent of total monetized benefits in 2015. Benefit
estimates in this table are nationwide (with the exception of visibility) and reflect NOX and SO2 reductions.
Ozone benefits are expected to occur for this rule, but are not estimated in this analysis. Visibility
benefits represent benefits in Class I areas in the southeastern and southwestern United States.
d Not all possible benefits or disbenefits are quantified and monetized in this analysis. B is the sum of all
unquantified benefits and disbenefits. Potential benefit categories that have not been quantified and
monetized are listed in Table IV-4.
e Valuation assumes discounting over the SAB-recommended 20-year segmented lag structure described in Chapter 4.
Results reflect 3 percent and 7 percent discount rates consistent with EPA and OMB guidelines for preparing
economic analyses (U.S. EPA, 2000; OMB, 2003).
f Net benefits are rounded to the nearest $100 million. Columnar totals may not sum due to rounding.
Table IV-4.--Unquantified and Nonmonetized Effects of the Clean Air
Visibility Rule
------------------------------------------------------------------------
Effects not included in primary
Pollutant/effect estimates--changes in:
------------------------------------------------------------------------
Ozone--Health a................... Premature mortality b.
Chronic respiratory damage.
Premature aging of the
lungs.
Nonasthma respiratory
emergency room visits.
Increased exposure to Uvb.
Hospital Admissions :
respiratory.
Emergency room visits for
asthma.
Minor restricted activity
days.
School loss days.
Asthma attacks.
Cardiovascular emergency
room visits.
Acute respiratory symptoms.
Ozone--Welfare.................... Yields for:
--Commercial forests,
--Fruits and vegetables, and
--Commercial and noncommercial
crops.
Damage to urban ornamental
plants.
Recreational demand from
damaged forest aesthetics.
Ecosystem functions.
Increased exposure to UVb.
PM--Health c...................... Premature mortality: short-
term exposuresd.
Low birth weight.
Pulmonary function.
Chronic respiratory
diseases other than chronic
bronchitis.
Nonasthma respiratory
emergency room visits.
Exposure to UVb (+/-) e.
PM--Welfare....................... Visibility in many Class I
areas.
Residential and
recreational visibility in non-
Class I areas.
Soiling and materials
damage.
Ecosystem functions.
Exposure to UVb (+/-)e.
Nitrogen and Sulfate Deposition-- Commercial forests due to
Welfare. acidic sulfate and nitrate
deposition.
Commercial freshwater
fishing due to acidic deposition.
Recreation in terrestrial
ecosystems due to acidic
deposition.
Existence values for
currently healthy ecosystems.
[[Page 39149]]
Commercial fishing,
agriculture, and forests due to
nitrogen deposition.
Recreation in estuarine
ecosystems due to nitrogen
deposition.
Ecosystem functions.
Passive fertilization due
to nitrogen deposition.
Mercury Health g.................. Incidence of neurological
disorders.
Incidence of learning
disabilities.
Incidence of developmental
delays.
Potential reproductive
effectsf.
Potential cardiovascular
effectsf, including:
--Altered blood pressure regulation
f
--Increased heart rate variability
f
--Incidence of myocardial
infarction f
Mercury Deposition Welfare g...... Impacts on birds and
mammals (e.g., reproductive
effects).
Impacts to commercial,
subsistence, and recreational
fishing.
------------------------------------------------------------------------
a In addition to primary economic endpoints, there are a number of
biological responses that have been associated with ozone health
effects including increased airway responsiveness to stimuli,
inflammation in the lung, acute inflammation and respiratory cell
damage, and increased susceptibility to respiratory infection. The
public health impact of these biological responses may be partly
represented by our quantified endpoints.
b Premature mortality associated with ozone is not currently included in
the primary analysis. Recent evidence suggests that short-term
exposures to ozone may have a significant effect on daily mortality
rates, independent of exposure to PM. EPA is currently conducting a
series of meta-analyses of the ozone mortality epidemiology
literature. EPA will consider including ozone mortality in primary
benefits analyses once a peer-reviewed methodology is available.
c In addition to primary economic endpoints, there are a number of
biological responses that have been associated with PM health effects
including morphological changes and altered host defense mechanisms.
The public health impact of these biological responses may be partly
represented by our quantified endpoints.
d While some of the effects of short term exposures are likely to be
captured in the estimates, there may be premature mortality due to
short term exposure to PM not captured in the cohort study upon which
the primary analysis is based.
e May result in benefits or disbenefits. See discussion in Section 5.3.4
for more details.
f These are potential effects as the literature is insufficient.
g Mercury emission reductions are not anticipated for BART for the EGU
source category due to the cap-and-trade program promulgated for the
Clean Air Mercury Rule (March 2005); however, the geographic location
of mercury reductions may change as a result of this rule. EPA
believes any such effects for these sources would be minimal. Mercury
reductions are expected for the non-EGU source categories. The mercury
reduction for BART from the non-EGU source categories is expected to
be small in comparison to reductions resulting from the recently
promulgated Clean Air Interstate Rule and the Clean Air Mercury Rule
(March 2005).
3. How Do the Benefits Compare to the Costs of This Final Rule?
In estimating the net benefits of regulation, the appropriate cost
measure is ``social costs.'' Social costs represent the welfare costs
of the rule to society. The social costs of this rule for the EGU and
non-EGU sector sources are estimated to range from approximately $0.3
to $2.9 billion in 2015. This range depends upon the control scenario
assumed and applicable discount rates of 3 percent and 7 percent. The
net benefits (social benefits minus social costs) of the rule range
from approximately $1.9 + B billion or $12.0 + B billion depending upon
the scenario evaluated and the applicable discount rate (3 and 7
percent) annually in 2015. Implementation of the rule is expected to
provide society with a substantial net gain in social welfare based on
economic efficiency criteria.
There is uncertainty surrounding the actions States are likely to
take to comply with the BART guidelines. States will determine BART-
eligible sources based upon CAA criteria, determine those BART-eligible
sources reasonably anticipated to cause or contribute to visibility
impairment in Class I areas and then apply a 5 factor test for BART
determinations. The range of estimated benefits, costs, and resulting
net benefits for BART reflects the uncertainty concerning States
responses to BART and represents EPA's best estimates of the benefit-
cost outcomes of alternative compliance scenarios.
The annualized cost of BART, as quantified here, is EPA's best
assessment of the cost of actions States are likely to take to comply
with the rule. The EGU portion of these costs are generated from
rigorous economic modeling of changes in the power sector due to the
BART rule and guidelines. This type of analysis using IPM has undergone
peer review and been upheld in Federal courts. The direct cost
includes, but is not limited to, capital investments in pollution
controls, operating expenses of the pollution controls, investments in
new generating sources, and additional fuel expenditures. The EPA
believes that these costs reflect, as closely as possible, the
additional costs of the BART rule and guidelines to industry. However,
there may exist certain costs that EPA has not quantified in these
estimates. These costs may include costs of transitioning to the BART,
such as the costs associated with the retirement of smaller or less
efficient EGUs, employment shifts as workers are retrained at the same
company or re-employed elsewhere in the economy. Costs may be
understated since an optimization model was employed that assumes cost
minimization, and the regulated community may not react in the same
manner to comply with the rule. Although EPA has not quantified these
potential additional costs, the Agency believes that they are small
compared to the quantified costs of the program on the power sector.
The annualized cost estimates presented are the best and most accurate
based upon available information.
The non-EGU portion of these costs are generated from extensive
cost modeling based on applying illustrative regulatory scenarios to
the non-EGU source categories. These costs represent potential impacts
to non-EGU sources from State-imposed BART requirements. The direct
cost includes, but is not limited to, capital investments in pollution
controls, operating and maintenance expenses of the pollution controls,
and additional fuel expenditures. The EPA believes that these costs
reflect, as closely as possible, the potential additional costs of the
BART rule and guidelines to industries with non-EGU sources. However,
there
[[Page 39150]]
may exist certain costs that EPA has not quantified in these estimates.
These costs may include costs of transitioning to the BART rule and
guidelines, such as the costs associated with the retirement of smaller
or less efficient non-EGUs, employment shifts as workers are retrained
at the same company or re-employed elsewhere in the economy, and costs
associated with applying both SO2 and NOX
controls at one facility at the same time. Costs may be understated
since the non-EGU cost modeling presumed a least-cost approach, and the
potentially regulated community may not react in the same manner to
comply with the rules. Although EPA has not quantified these costs, the
Agency believes that they are small compared to the quantified costs of
the program on industries with potentially affected non-EGU sources.
The annualized cost estimates presented are the best and most accurate
based upon available information. In a separate analysis, EPA estimates
the indirect costs and impacts of higher electricity prices and costs
applicable to the non-EGU sectors on the entire economy [see Regulatory
Impact Analysis for the Final Clean Visibility Rule, Appendix A (June
2005)].
The costs presented here are EPA's best estimate of the direct
private costs of the BART rule and guidelines. For purposes of benefit-
cost analysis of this rule, EPA has also estimated the additional costs
of BART using alternate discount rates for calculating the social
costs, parallel to the range of discount rates used in the estimates of
the benefits of BART (3 percent and 7 percent). Using these alternate
discount rates, the social costs of BART range from $0.3 to $2.9
billion in 2015. (Note the portion of these annual costs associated
with non-EGU sources represents incremental private cost estimates that
are used as a proxy for the social costs of the rule.)
Every benefit-cost analysis examining the potential effects of a
change in environmental protection requirements is limited to some
extent by data gaps, limitations in model capabilities (such as
geographic coverage), and uncertainties in the underlying scientific
and economic studies used to configure the benefit and cost models.
Gaps in the scientific literature often result in the inability to
estimate quantitative changes in health and environmental effects. Gaps
in the economics literature often result in the inability to assign
economic values even to those health and environmental outcomes that
can be quantified. While uncertainties in the underlying scientific and
economics literatures (that may result in overestimation or
underestimation of benefits) are discussed in detail in the economic
analyses and its supporting documents and references, the key
uncertainties which have a bearing on the results of the benefit-cost
analysis of this rule include the following:
Uncertainty concerning actions States will undertake to
comply with BART;
EPA's inability to quantify potentially significant
benefit categories;
Uncertainties in population growth and baseline incidence
rates;
Uncertainties in projection of emissions inventories and
air quality into the future;
Uncertainty in the estimated relationships of health and
welfare effects to changes in pollutant concentrations including the
shape of the C-R function, the size of the effect estimates, and the
relative toxicity of the many components of the PM mixture;
Uncertainties in exposure estimation; and
Uncertainties associated with the effect of potential
future actions to limit emissions.
Despite these uncertainties, we believe the benefit-cost analysis
provides a reasonable indication of the expected economic benefits of
the rulemaking in future years under a set of reasonable assumptions.
In valuing reductions in premature fatalities associated with PM,
we used a value of $5.5 million per statistical life. This represents a
central value consistent with a range of values from $1 to $10 million
suggested by recent meta-analyses of the wage-risk value of statistical
life (VSL) literature.\87\
---------------------------------------------------------------------------
\87\ Mrozek, J.R. and L.O. Taylor, What determines the value of
a life? A Meta Analysis, Journal of Policy Analysis and Management
21 (2), pp. 253-270.
---------------------------------------------------------------------------
The benefits estimates generated for this rule are subject to a
number of assumptions and uncertainties, that are discussed throughout
the Regulatory Impact Analysis document [Regulatory Impact Analysis for
the Final Clean Air Visibility Rule (April 2005)]. As Table IV-2
indicates, total benefits are driven primarily by the reduction in
premature fatalities each year. Elaborating on the previous uncertainty
discussion, some key assumptions underlying the primary estimate for
the premature mortality category include the following:
(1) EPA assumes inhalation of fine particles is causally associated
with premature death at concentrations near those experienced by most
Americans on a daily basis. Plausible biological mechanisms for this
effect have been hypothesized for the endpoints included in the primary
analysis and the weight of the available epidemiological evidence
supports an assumption of causality.
(2) EPA assumes all fine particles, regardless of their chemical
composition, are equally potent in causing premature mortality. This is
an important assumption, because the proportion of certain components
in the PM mixture produced via precursors emitted from EGUs may differ
significantly from direct PM released from automotive engines and other
industrial sources, but no clear scientific grounds exist for
supporting differential effects estimates by particle type.
(3) EPA assumes the C-R function for fine particles is
approximately linear within the range of ambient concentrations under
consideration. In the PM Criteria Document, EPA recognizes that for
individuals and specific health responses there are likely threshold
levels, but there remains little evidence of thresholds for PM-related
effects in populations.\88\ Where potential threshold levels have been
suggested, they are at fairly low levels with increasing uncertainty
about effects at lower ends of the PM2.5 concentration
ranges. Thus, EPA estimates include health benefits from reducing the
fine particles in areas with varied concentrations of PM, including
both regions that are in attainment with fine particle standard and
those that do not meet the standard.
\88\ U.S. EPA. (2004). Air Quality Criteria for Particulate
Matter. Research Triangle Park, NC: National Center for
Environmental Assessment-RTP Office; Report No. EPA/600/P-99/002aD.
---------------------------------------------------------------------------
The EPA recognizes the difficulties, assumptions, and inherent
uncertainties in the overall enterprise. The analyses upon which the
BART rule and guidelines are based were selected from the peer-reviewed
scientific literature. We used up-to-date assessment tools, and we
believe the results are highly useful in assessing this rule.
There are a number of health and environmental effects that we were
unable to quantify or monetize. A complete benefit-cost analysis of
BART requires consideration of all benefits and costs expected to
result from the rule, not just those benefits and costs which could be
expressed here in dollar terms. A listing of the benefit categories
that were not quantified or monetized in our estimate are provided in
Table IV-4. These effects are denoted by ``B'' in Table IV-3 above, and
are additive to the estimates of benefits.
[[Page 39151]]
4. What Are the Unquantified and Unmonetized Benefits of BART Emissions
Reductions?
Important benefits beyond the human health and welfare benefits
resulting from reductions in ambient levels of PM2.5 and
ozone are expected to occur from this rule. These other benefits occur
both directly from NOX and SO2 emissions
reductions, and indirectly through reductions in co-pollutants such as
mercury. These benefits are listed in Table IV-4. Some of the more
important examples include: Reductions in NOX and
SO2 emissions required by BART will reduce acidification
and, in the case of NOX, eutrophication of water bodies.
Reduced nitrate contamination of drinking water is another possible
benefit of the rule. This final rule will also reduce acid and
particulate deposition that cause damages to cultural monuments, as
well as, soiling and other materials damage.
To illustrate the important nature of benefit categories we are
currently unable to monetize, we discuss two categories of public
welfare and environmental impacts related to reductions in emissions
required by BART: reduced acid deposition and reduced eutrophication of
water bodies.
a. What Are the Benefits of Reduced Deposition of Sulfur and Nitrogen
to Aquatic, Forest, and Coastal Ecosystems?
Atmospheric deposition of sulfur and nitrogen, more commonly known
as acid rain, occurs when emissions of SO2 and
NOX react in the atmosphere (with water, oxygen, and
oxidants) to form various acidic compounds. These acidic compounds fall
to earth in either a wet form (rain, snow, and fog) or a dry form
(gases and particles). Prevailing winds can transport acidic compounds
hundreds of miles, across State borders. Acidic compounds (including
small particles such as sulfates and nitrates) cause many negative
environmental effects, including acidification of lakes and streams,
harm to sensitive forests, and harm to sensitive coastal ecosystems.
i. Acid Deposition and Acidification of Lakes and Streams
The extent of adverse effects of acid deposition on freshwater and
forest ecosystems depends largely upon the ecosystem's ability to
neutralize the acid. The neutralizing ability [key indicator is termed
Acid Neutralizing Capacity (ANC)] depends largely on the watershed's
physical characteristics: geology, soils, and size. Waters that are
sensitive to acidification tend to be located in small watersheds that
have few alkaline minerals and shallow soils. Conversely, watersheds
that contain alkaline minerals, such as limestone, tend to have waters
with a high ANC. Areas especially sensitive to acidification include
portions of the Northeast (particularly, the Adirondack and Catskill
Mountains, portions of New England, and streams in the mid-Appalachian
highlands) and southeastern streams.
ii. Acid Deposition and Forest Ecosystem Impacts
Current understanding of the effects of acid deposition on forest
ecosystems focuses on the effects of ecological processes affecting
plant uptake, retention, and cycling of nutrients within forest
ecosystems. Recent studies indicate that acid deposition is at least
partially responsible for decreases in base cations (calcium,
magnesium, potassium, and others) from soils in the northeastern and
southeastern United States. Losses of calcium from forest soils and
forested watersheds have now been documented as a sensitive early
indicator of soil response to acid deposition for a wide range of
forest soils in the United States.
In red spruce stands, a clear link exists between acid deposition,
calcium supply, and sensitivity to abiotic stress. Red spruce uptake
and retention of calcium is impacted by acid deposition in two main
ways: leaching of important stores of calcium from needles and
decreased root uptake of calcium due to calcium depletion from the soil
and aluminum mobilization. These changes increase the sensitivity of
red spruce to winter injuries under normal winter conditions in the
Northeast, result in the loss of needles, slow tree growth, and impair
the overall health and productivity of forest ecosystems in many areas
of the eastern United States. In addition, recent studies of sugar
maple decline in the Northeast demonstrate a link between low base
cation availability, high levels of aluminum and manganese in the soil,
and increased levels of tree mortality due to native defoliating
insects.
Although sulfate is the primary cause of base cation leaching,
nitrate is a significant contributor in watersheds that are nearly
nitrogen saturated. Base cation depletion is a cause for concern
because of the role these ions play in surface water acid
neutralization and their importance as essential nutrients for tree
growth (calcium, magnesium and potassium).
This regulatory action will decrease acid deposition in the
transport region and is likely to have positive effects on the health
and productivity of forest systems in the region.
iii. Coastal Ecosystems
Since 1990, a large amount of research has been conducted on the
impact of nitrogen deposition to coastal waters. Nitrogen is often the
limiting nutrient in coastal ecosystems. Increasing the levels of
nitrogen in coastal waters can cause significant changes to those
ecosystems. In recent decades, human activities have accelerated
nitrogen nutrient inputs, causing excessive growth of algae and leading
to degraded water quality and associated impairments of estuarine and
coastal resources.
Atmospheric deposition of nitrogen is a significant source of
nitrogen to many estuaries. The amount of nitrogen entering estuaries
due to atmospheric deposition varies widely, depending on the size and
location of the estuarine watershed and other sources of nitrogen in
the watershed. There are a few estuaries where atmospheric deposition
of nitrogen contributes well over 40 percent of the total nitrogen
load; however, in most estuaries for which estimates exist, the
contribution from atmospheric deposition ranges from 15-30 percent. The
area of the country with the highest air deposition rates (30 percent
deposition rates) includes many estuaries along the northeast seaboard
from Massachusetts to the Chesapeake Bay and along the central Gulf of
Mexico coast.
In 1999, National Oceanic and Atmospheric Administration (NOAA)
published the results of a 5-year national assessment of the severity
and extent of estuarine eutrophication. An estuary is defined as the
inland arm of the sea that meets the mouth of a river. The 138
estuaries characterized in the study represent more than 90 percent of
total estuarine water surface area and the total number of U.S.
estuaries. The study found that estuaries with moderate to high
eutrophication represented 65 percent of the estuarine surface area.
Eutrophication is of particular concern in coastal areas with poor
or stratified circulation patterns, such as the Chesapeake Bay, Long
Island Sound, and the Gulf of Mexico. In such areas, the
``overproduced'' algae tends to sink to the bottom and decay, using all
or most of the available oxygen and thereby reducing or eliminating
populations of bottom-feeder fish and shellfish, distorting the normal
population balance between different aquatic organisms, and in extreme
cases, causing dramatic fish kills. Severe and persistent
eutrophication often directly impacts human activities. For example,
[[Page 39152]]
fishery resource losses can be caused directly by fish kills associated
with low dissolved oxygen and toxic blooms. Declines in tourism occur
when low dissolved oxygen causes Noxious smells and floating mats of
algal blooms create unfavorable aesthetic conditions. Risks to human
health increase when the toxins from algal blooms accumulate in edible
fish and shellfish, and when toxins become airborne, causing
respiratory problems due to inhalation. According to the NOAA report,
more than half of the nation's estuaries have moderate to high
expressions of at least one of these symptoms'an indication that
eutrophication is well developed in more than half of U.S. estuaries.
This rule is anticipated to reduce nitrogen deposition in the
nation. Thus, reductions in the levels of nitrogen deposition will have
a positive impact upon current eutrophic conditions in estuaries and
coastal areas in the country.
5. Are There Health or Welfare Disbenefits of the BART That Have Not
Been Quantified?
In contrast to the additional benefits of the rule discussed above,
it is also possible that this rule will result in disbenefits in some
areas of the region. Current levels of nitrogen deposition in these
areas may provide passive fertilization for forest and terrestrial
ecosystems where nutrients are a limiting factor and for some
croplands.
The effects of ozone and PM on radiative transfer in the atmosphere
can also lead to effects of uncertain magnitude and direction on the
penetration of ultraviolet light and climate. Ground level ozone makes
up a small percentage of total atmospheric ozone (including the
stratospheric layer) that attenuates penetration of ultraviolet--b
(UVb) radiation to the ground. The EPA's past evaluation of the
information indicates that potential disbenefits would be small,
variable, and with too many uncertainties to attempt quantification of
relatively small changes in average ozone levels over the course of a
year (EPA, 2005a). The EPA's most recent provisional assessment of the
currently available information indicates that potential but
unquantifiable benefits may also arise from ozone-related attenuation
of UVb radiation (EPA, 2005b). Sulfate and nitrate particles also
scatter UVb, which can decrease exposure of horizontal surfaces to UVb,
but increase exposure of vertical surfaces. In this case as well, both
the magnitude and direction of the effect of reductions in sulfate and
nitrate particles are too uncertain to quantify (EPA, 2004). Ozone is a
greenhouse gas, and sulfates and nitrates can reduce the amount of
solar radiation reaching the earth, but EPA believes that we are unable
to quantify any net climate-related disbenefit or benefit associated
with the combined ozone and PM reductions in this rule.
B. Paperwork Reduction Act
Today's rule clarifies, but does not modify the information
collection requirements for BART. Therefore, this action does not
impose any new information collection burden. However, the OMB has
previously approved the information collection requirements contained
in the existing regulations [40 CFR Part 51] under the provisions of
the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and has assigned
OMB control number 2060-0421, EPA ICR number 1813.04. A copy of the OMB
approved Information Collection Request (ICR) may be obtained from
Susan Auby, Collection Strategies Division; U.S. Environmental
Protection Agency (2822T); 1200 Pennsylvania Ave., NW, Washington, DC
20460 or by calling (202) 566-1672.
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.
C. Regulatory Flexibility Act
EPA has determined that it is not necessary to prepare a regulatory
flexibility analysis in connection with this final rule.
For purposes of assessing the impacts of today's rule on small
entities, small entity is defined as: (1) A small business as defined
by the Small Business Administrations' regulations at 13 CFR 121.201;
(2) a small governmental jurisdiction that is a government of a city,
county, town, school district or special district with a population of
less than 50,000; and (3) a small organization that is any not-for-
profit enterprise which is independently owned and operated and is not
dominant in its field.
Table IV-5 lists potentially impacted BART industry source
categories and the current applicable small business criteria
established by the Small Business Administration.
Table IV-5. Potentially Affected BART Source Categories and Small Business Size Standards
----------------------------------------------------------------------------------------------------------------
NAICS \a\ Description Size standard \b\
----------------------------------------------------------------------------------------------------------------
221112 \c,d\.......................... Fossil fuel-fired electric electric output <= 4 million megawatt
utility steam generating hours.
units.
212112................................ Bituminous Coal Underground 500 Employees.
Mining.
311221................................ Wet Corn Milling............. 750 Employees.
311311................................ Sugarcane Mills.............. 500 Employees.
311313................................ Beet Sugar Manufacturing..... 750 Employees.
31214................................. Distilleries................. 750 Employees.
321212................................ Softwood Veneer and Plywood 500 Employees.
Manufacturing.
322121................................ Paper (except Newsprint) 750 Employees.
Mills (pt).
325188................................ All Other Basic Inorganic 1,000 Employees.
Chemical Manufacturing (pt).
325221................................ Cellulosic Organic Fiber 1,000 Employees.
Manufacturing.
325222................................ Noncellulosic Organic Fiber 1,000 Employees.
Manufacturing.
325182................................ Carbon Black Manufacturing 500 Employees.
(pt).
327213................................ Glass Container Manufacturing 750 Employees.
327212................................ Other Pressed and Blown Glass 750 Employees.
and Glassware Manufacturing.
[[Page 39153]]
32731................................. Cement Manufacturing......... 750 Employees.
32741................................. Lime Manufacturing........... 500 Employees.
331111................................ Iron and Steel Mills......... 1,000 Employees.
331315................................ Aluminum Sheet, Plate, and 750 Employees.
Foil Manufacturing.
331319................................ Other Aluminum Rolling and 750 Employees.
Drawing.
22121................................. Natural Gas Distribution..... 500 Employees.
----------------------------------------------------------------------------------------------------------------
\a\ North American Industry Classification System.
\b\ Small Business Administration Size Criteria.
\c\ Include NAICS categories for source categories that own and operate electric generating units only.
\d\ Federal, State, or local government-owned and operated establishments are classified according to the
activity in which they are engaged.
After considering the economic impacts of today's final rule on
small entities, EPA has concluded that this action will not have a
significant economic impact on a substantial number of small entities.
This final rule will not impose any direct requirements on small
entities. The rule would apply to States, not to small entities.
Courts have interpreted the RFA to require a regulatory flexibility
analysis only when small entities will be subject to the requirements
of the rule. See Motor and Equip. Mfrs. Ass'n v. Nichols, 142 F. 3d 449
(D.C. Cir., 1998); United Distribution Cos. v. FERC, 88 F. 3d 1105,
1170 (D.C. Cir., 1996); Mid-Tex Elec. Co-op, Inc. v. FERC, 773 F . 2d
327, 342 (D.C. Cir., 1985) (agency's certification need only consider
the rule's impact on entities subject to the rule).
BART requirements in the regional haze rule require BART
determinations for a select list of major stationary sources defined by
section 169A(g)(7) of the CAA. However, as noted in the proposed and
final regional haze rules, the State's determination of BART for
regional haze involves some State discretion in considering a number of
factors set forth in section 169A(g)(2), including the costs of
compliance.
Further, the final regional haze rule allows States to adopt
alternative measures in lieu of requiring the installation and
operation of BART at these major stationary sources. As a result, the
potential consequences of the BART provisions of the regional haze rule
(as clarified in today's rule) at specific sources are speculative. Any
requirements for BART will be established by State rulemakings. The
States would accordingly exercise substantial intervening discretion in
implementing the BART requirements of the regional haze rule and
today's guidelines.
EPA has undertaken an illustrative analysis to assess the potential
small business impacts of BART based upon EPA's assessment of the
actions States may take to comply with the BART rule and guidelines.
For this final rule, the engineering analysis conducted for the
rulemaking identified 491 EGU units potentially affected by the outcome
of this rule. Using unit ORIS \89\ numbers and the Energy Information
Administration's publicly available 2002 electric generator databases
(Form EIA 860 and Form EIA 861), we identified utility names, nameplate
capacity for affected units, and net electricity generation potentially
affected by this rule. After identifying these units, we excluded units
that are located in CAIR regions in order to identify those units most
likely affected by the BART regulatory program. After an assessment of
the ownership of these remaining units, we identified 2 potentially
affected small entities in the EGU sector. We used a cost-to-sales
approach (comparison of expected annual costs of emission controls to
annual sales revenue or government entity budgets for the affected
small entity) to assess the potential impacts of BART for these
affected entities. Using data from the cost analysis, EPA found one of
these small entities may experience a cost-to-sales ratio of 3 percent
of sales. The other affected small entity in the EGU sector does not
face additional compliance costs associated with the rule.
---------------------------------------------------------------------------
\89\ An ORIS code is a 4 digit number assigned by the Energy
Information Administration (EIA) at the U.S. Department of Energy to
power plants owned by utilities.
---------------------------------------------------------------------------
The engineering analysis conducted for the rulemaking identified
over 2,000 records associated with affected non-EGU units (all source
categories listed in table IV-5 other than EGUs--NAICS 221112)
potentially affected by the rule. Using publicly available sales and
employment databases, plant names, and locations, we identified 279
entities and potential owners. In order to classify affected ultimate
entities as small or large, EPA collected information on facility
names, parent company sales, and parent company employment data. Data
were compared with the appropriate size standard and entities were
classified as small or large according to Small Business
Administration's definitions. For example, ultimate parent companies of
cement producers with employment exceeding 750 employees were
classified as large companies. This process identified 36 small
companies and 195 large companies potentially impacted as a result
promulgating this rule. The remaining 48 entities were either
government-owned (25 entities, primarily state universities) or parent
ownership could not be definitively identified using available
databases (23 entities).
Using the cost-to-sales approach described above, EPA found that
five non-EGU source category small entities may potentially be affected
at or above 3 percent. Two entities may be affected between one and
three percent, and the remaining small entity cost-to-sales ratios are
below one percent. The median cost-to-sales ratio for non-EGU source
category small entities is estimated to be 0.3 percent and could
potentially range from 0 to 20 percent. As previously discussed this
analysis is illustrative and based upon EPA's assessment of actions
States are likely to take as a result of the BART rule and guidelines
promulgated today.
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates Reform Act of 1995 (Public Law
104-4) establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and Tribal
governments and the private sector. Under section 202 of UMRA, 2 U.S.C.
1532, EPA generally must prepare a written statement, including a cost-
benefit analysis, for any proposed or final rule that ``includes any
Federal mandate that may result in the expenditure by State, local, and
tribal governments, in the aggregate, or by the private sector, of
$100,000,000 or more * * * in any one year.'' A ``Federal
[[Page 39154]]
mandate'' is defined under section 421(6), 2 U.S.C. 658(6), to include
a ``Federal intergovernmental mandate.'' A ``Federal intergovernmental
mandate,'' in turn, is defined to include a regulation that ``would
impose an enforceable duty upon State, local, or tribal governments,''
section 421(5)(A)(I), 2 U.S.C. 658(5)(A)(I). A ``Federal private sector
mandate'' includes a regulation that ``would impose an enforceable duty
upon the private sector,'' with certain exceptions, section 421(7)(A),
2 U.S.C. 658(7)(A).
Before promulgating an EPA rule for which a written statement is
needed under section 202 of UMRA, section 205, 2 U.S.C. 1535, of UMRA
generally requires EPA to identify and consider a reasonable number of
regulatory alternatives and adopt the least costly, most cost
effective, or least burdensome alternative that achieves the objectives
of the rule.The RIA prepared by EPA and placed in the docket for this
rulemaking is consistent with the requirements of section 202 of the
UMRA. Furthermore, EPA is not directly establishing any regulatory
requirements that may significantly or uniquely affect small
governments, including tribal governments. Thus, EPA is not obligated
to develop under section 203 of the UMRA a small government agency
plan. Further, EPA carried out consultations with the governmental
entities affected by this rule in a manner consistent with the
intergovernmental consultation provisions of section 204 of the UMRA.
The EPA also believes that today's rule meets the UMRA requirement
in section 205 to select the least costly and burdensome alternative in
light of the statutory mandate for BART. As explained above, we are
promulgating the BART rule and guidelines following the D.C. Circuit's
remand of the BART provisions in the 1999 regional haze rule. The 1999
regional haze rule provides substantial flexibility to the States,
allowing them to adopt alternative measures such as a trading program
in lieu of requiring the installation and operation of BART. The
provisions governing such alternative measures were affected by a more
recent decision of the D.C. Circuit and will be revised in a separate
rulemaking process. Today's rule will not restrict the ability of the
States to adopt such alternatives measures once those revisions to the
regional haze rule have been made final. This will provide an
alternative to BART that gives States the ability to choose the least
costly and least burdensome alternative. Today's rule also allows
States affected by the Clean Air Interstate Rule to utilize emission
reductions achieved by EGUs under that rule to satisfy BART
requirements for those sources. This will provide those States with
another cost effective and less burdensome alternative to BART.
The EPA is not reaching a final conclusion as to the applicability
of UMRA to today's rulemaking action. The reasons for this are
discussed in the 1999 regional haze rule (64 FR 35762) and in the 2001
BART guidelines proposal (66 FR 38111-38112). Notwithstanding this, the
discussion in chapter 9 of the RIA constitutes the UMRA statement that
would be required by UMRA if its statutory provisions applied.
Consequently, we continue to believe that it is not necessary to reach
a conclusion as to the applicability of the UMRA requirements.
E. Executive Order 13132: Federalism
Executive Order 13132, entitled Federalism (64 FR 43255, August 10,
1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
Such policies are defined in the Executive Order to include regulations
that have ``substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.'' Under section 6 of Executive Order 13132, EPA may not
issue a regulation that has federalism implications, that imposes
substantial direct compliance costs, and that is not required by
statute, unless the Federal government provides the funds necessary to
pay the direct compliance costs incurred by State and local
governments, or EPA consults with State and local officials early in
the process of developing the regulation. The EPA also may not issue a
regulation that has federalism implications and that preempts State law
unless EPA consults with State and local officials early in the process
of developing the regulation.
We have concluded that today's action, promulgating the BART
guidelines, will not have federalism implications, as specified in
section 6 of the Executive Order 13132 (64 FR 43255, August 10, 1999)
because it will not have substantial direct effects on the States, nor
substantially alter the relationship or the distribution of power and
responsibilities between the States and the Federal government.
Nonetheless, we consulted with a wide scope of State and local
officials, including the National Governors Association, the National
League of Cities, the National Conference of State Legislatures, the U.
S. Conference of Mayors, the National Association of Counties, the
Council of State Governments, the International City/County Management
Association, and the National Association of Towns and Townships during
the course of developing this rule.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by Tribal officials in the development of regulatory
policies that have Tribal implications.''
This rule does not have Tribal implications as defined by Executive
Order 13175. It does not have a substantial direct effect on one or
more Indian Tribes. Furthermore, this rule does not affect the
relationship or distribution of power and responsibilities between the
Federal government and Indian Tribes. The CAA and the TAR establish the
relationship of the Federal government and Tribes in developing plans
to address air quality issues, and this rule does nothing to modify
that relationship. This rule does not have Tribal implications, and
Executive Order 13175 does not apply to this rulemaking.
G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
Executive Order 13045, ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that (1) is determined to be ``economically significant''
as defined under Executive Order 12866 and (2) concerns an
environmental health or safety risk that EPA has reason to believe may
have a disproportionate effect on children. If the regulatory action
meets both criteria, Section 5-501 of the Order directs the Agency to
evaluate the environmental health or safety effects of the planned rule
on children and to explain why the planned regulation is preferable to
other potentially effective and reasonably feasible alternatives
considered by the Agency.
EPA interprets Executive Order 13045 as applying only to those
regulatory actions that are based on health and safety risks, such that
the analysis required under section 5-501 of the
[[Page 39155]]
Order has the potential to influence the regulation. The BART rule and
guidelines are not subject to the Executive Order because the rule and
guidelines do not involve decisions on environmental health or safety
risks that may disproportionately affect children. The EPA believes
that the emissions reductions from the control strategies considered in
this rulemaking will further improve air quality and will further
improve children's health.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
We have conducted a Regulatory Impact Analysis for this rule, that
includes an analysis of energy impacts and is contained in the docket
(Docket No. OAR-2002-0076). This rule is not a ``significant energy
action'' as defined in Executive Order 13211, ``Actions Concerning
Regulations That Significantly Affect Energy Supply, Distribution, or
Use'' (66 FR 28355 (May 22, 2001)) because it is not likely to have a
significant adverse effect on the supply, distribution, or use of
energy. This rule is not a ``significant energy action,'' because it
will have less than a 1 percent impact on the cost of energy production
and does not exceed other factors described by OMB that may indicate a
significant adverse effect. (See, ``Guidance for Implementing E.O.
13211,'' OMB Memorandum 01-27 (July 13, 2001) http://www.whitehouse.gov/omb/memoranda/m01-27.html.) Specifically, the
presumptive requirements for EGUs for this rule, when fully
implemented, are expected have a 0.25 percent impact on the cost of
energy production for the nation in 2015. States must use the
guidelines in making BART determinations for power plants with a
generating capacity in excess of 750 MW. Our analysis evaluates the
impact of the presumptive requirements for these sources and does not
consider any possible additional controls for EGU sources or non-EGU
sources that States may require. Although States may choose to use the
guidelines in establishing BART limits for non-EGUs , ultimately States
will determine the sources subject to BART and the appropriate level of
control for such sources.
We are finalizing today's rule following the D.C. Circuit's remand
of the BART provisions in the 1999 regional haze rule. The 1999
regional haze rule provides substantial flexibility to the States,
allowing them to adopt alternative measures such as a trading program
in lieu of requiring the installation and operation of BART. The
provisions governing such alternative measures were affected by a more
recent decision of the D.C. Circuit and will be revised in a separate
rulemaking process. This rulemaking will not restrict the ability of
the States to adopt alternative measures once those revisions to the
regional haze rule have been made final. This will provide an
alternative to BART that reduces the overall cost of the regulation and
its impact on the energy supply. Today's rule also allows States
affected by the Clean Air Interstate Rule to utilize emission
reductions achieved by EGUs under that rule to satisfy BART
requirements for those sources. This will provide those States with
another cost effective and less burdensome alternative to BART. The
BART rule itself offers flexibility by offering the choice of meeting
SO2 requirements between an emission rate and a removal
rate.
For a State that chooses to require case-by-case BART, today's rule
would establish presumptive levels of controls for SO2 and
NOX for certain EGUs that the State finds are subject to
BART. Based on its consideration of various factors set forth in the
regulations; however, a State may conclude that a different level of
control is appropriate. The States will accordingly exercise
substantial intervening discretion in implementing the final rule.
Additionally, we have assessed that the compliance dates for the rule
will provide adequate time for EGUs to install the required emission
controls.
I. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer Advancement Act
of 1995 (NTTAA), Public Law 104-113, section 12(d)(15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards (VCS) in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by VCS bodies. The NTTAA directs EPA to provide Congress,
through OMB, explanations when the EPA decides not to use VCS.
This action does not involve technical standards; thus, EPA did not
consider the use of any VCS.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations
Executive Order 12898, ``Federal Actions to Address Environmental
Justice in Minority Populations and Low-Income Populations,'' requires
federal agencies to consider the impact of programs, policies, and
activities on minority populations and low-income populations.
According to EPA guidance,\90\ agencies are to assess whether minority
or low-income populations face risks or a rate of exposure to hazards
that are significant and that ``appreciably exceed or is likely to
appreciably exceed the risk or rate to the general population or to the
appropriate comparison group.'' (EPA, 1998)
---------------------------------------------------------------------------
\90\ U.S. Environmental Protection Agency, 1998. Guidance for
Incorporating Environmental Justice Concerns in EPA's NEPA
Compliance Analyses. Office of Federal Activities, Washington, D.C.,
April, 1998.
---------------------------------------------------------------------------
In accordance with Executive Order 12898, the Agency has considered
whether this rule may have disproportionate negative impacts on
minority or low income populations. Negative impacts to these sub-
populations that appreciably exceed similar impacts to the general
population are not expected because the Agency expects this rule to
lead to reductions in air pollution emissions and exposures generally.
K. Congressional Review Act
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. The EPA will submit a report containing this rule and
other required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is a ``major rule'' as defined by 5 U.S.C.
804(2).
List of Subjects in 40 CFR Part 51
Environmental protection, Air pollution control, Administrative
practice and procedure, Intergovernmental relations, Lead, Nitrogen
dioxide, Ozone, Particulate matter, Reporting and recordkeeping
[[Page 39156]]
requirements, Sulfur oxides, Volatile organic compounds.
Dated: June 15, 2005.
Stephen L. Johnson,
Administrator.
0
For the reasons set forth in the preamble, part 51 of chapter I of
title 40 of the Code of Federal Regulations is amended as follows:
PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF
IMPLEMENTATION PLANS
0
1. The authority citation for part 51 continues to read as follows:
Authority: 23 U.S.C. 101; 42 U.S.C. 7410-7671q.
0
2. Section 51.302 is amended by revising paragraph (c)(4)(iii) to read
as follows:
Sec. 51.302 Implementation control strategies for reasonably
attributable visibility impairment.
* * * * *
(c) * * *
(4) * * *
(iii) BART must be determined for fossil-fuel fired generating
plants having a total generating capacity in excess of 750 megawatts
pursuant to ``Guidelines for Determining Best Available Retrofit
Technology for Coal-fired Power Plants and Other Existing Stationary
Facilities'' (1980), which is incorporated by reference, exclusive of
appendix E to the Guidelines, except that options more stringent than
NSPS must be considered. Establishing a BART emission limitation
equivalent to the NSPS level of control is not a sufficient basis to
avoid the analysis of control options required by the guidelines. This
document is EPA publication No. 450/3-80-009b and has been approved for
incorporation by reference by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. It is for sale from
the U.S. Department of Commerce, National Technical Information
Service, 5285 Port Royal Road, Springfield, Virginia 22161. It is also
available for inspection from the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/index.html.
* * * * *
0
3. Section 51.308 is amended by revising paragraph (b), removing and
reserving paragraph (c), revising paragraphs (e)(1)(ii), (e)(3), and
(e)(4), and adding paragaphs (e)(5) and (6) to read as follows:
Sec. 51.308 Regional haze program requirements.
* * * * *
(b) When are the first implementation plans due under the regional
haze program? Except as provided in Sec. 51.309(c), each State
identified in Sec. 51.300(b)(3) must submit, for the entire State, an
implementation plan for regional haze meeting the requirements of
paragraphs (d) and (e) of this section no later than December 17, 2007.
(c) [Reserved]
* * * * *
(e) * * *
(1) * * *
(ii) A determination of BART for each BART-eligible source in the
State that emits any air pollutant which may reasonably be anticipated
to cause or contribute to any impairment of visibility in any mandatory
Class I Federal area. All such sources are subject to BART.
(A) The determination of BART must be based on an analysis of the
best system of continuous emission control technology available and
associated emission reductions achievable for each BART-eligible source
that is subject to BART within the State. In this analysis, the State
must take into consideration the technology available, the costs of
compliance, the energy and nonair quality environmental impacts of
compliance, any pollution control equipment in use at the source, the
remaining useful life of the source, and the degree of improvement in
visibility which may reasonably be anticipated to result from the use
of such technology.
(B) The determination of BART for fossil-fuel fired power plants
having a total generating capacity greater than 750 megawatts must be
made pursuant to the guidelines in appendix Y of this part (Guidelines
for BART Determinations Under the Regional Haze Rule).
(C) Exception. A State is not required to make a determination of
BART for SO2 or for NOX if a BART-eligible source
has the potential to emit less than 40 tons per year of such
pollutant(s), or for PM10 if a BART-eligible source emits
less than 15 tons per year of such pollutant.
* * * * *
(3) A State which opts under 40 CFR 51.308(e)(2) to implement an
emissions trading program or other alternative measure rather than to
require sources subject to BART to install, operate, and maintain BART
may satisfy the final step of the demonstration required by that
section as follows: If the distribution of emissions is not
substantially different than under BART, and the alternative measure
results in greater emission reductions, then the alternative measure
may be deemed to achieve greater reasonable progress. If the
distribution of emissions is significantly different, the State must
conduct dispersion modeling to determine differences in visibility
between BART and the trading program for each impacted Class I area,
for the worst and best 20 percent of days. The modeling would
demonstrate ``greater reasonable progress'' if both of the following
two criteria are met:
(i) Visibility does not decline in any Class I area, and
(ii) There is an overall improvement in visibility, determined by
comparing the average differences between BART and the alternative over
all affected Class I areas.
(4) A State that opts to participate in the Clean Air Interstate
Rule cap-and-trade and trade program under part 96 AAA-EEE need not
require affected BART-eligible EGU's to install, operate, and maintain
BART. A State that chooses this option may also include provisions for
a geographic enhancement to the program to address the requirement
under Sec. 51.302(c) related to BART for reasonably attributable
impairment from the pollutants covered by the CAIR cap-and-trade
program.
(5) After a State has met the requirements for BART or implemented
emissions trading program or other alternative measure that achieves
more reasonable progress than the installation and operation of BART,
BART-eligible sources will be subject to the requirements of paragraph
(d) of this section in the same manner as other sources.
(6) Any BART-eligible facility subject to the requirement under
paragraph (e) of this section to install, operate, and maintain BART
may apply to the Administrator for an exemption from that requirement.
An application for an exemption will be subject to the requirements of
Sec. 51.303(a)(2)-(h).
* * * * *
0
4. Appendix Y to Part 51 is added to read as follows:
Appendix Y to Part 51--Guidelines for BART Determinations Under the
Regional Haze Rule
Table of Contents
I. Introduction and Overview
A. What is the purpose of the guidelines?
B. What does the CAA require generally for improving visibility?
C. What is the BART requirement in the CAA?
D. What types of visibility problems does EPA address in its
regulations?
[[Page 39157]]
E. What are the BART requirements in EPA's regional haze
regulations?
F. What is included in the guidelines?
G. Who is the target audience for the guidelines?
H. Do EPA regulations require the use of these guidelines?
II. How to Identify BART-eligible Sources
A. What are the steps in identifying BART-eligible sources?
1. Step 1: Identify emission units in the BART categories
2. Step 2: Identify the start-up dates of the emission units
3. Step 3: Compare the potential emissions to the 250 ton/yr
cutoff
4. Final step: Identify the emission units and pollutants that
constitute the BART-eligible source.
III. How to Identify Sources ``Subject to BART''
IV. The BART Determination: Analysis of BART Options
A. What factors must I address in the BART Analysis?
B. What is the scope of the BART review?
C. How does a BART review relate to maximum achievable control
technology (MACT) standards under CAA section 112?
D. What are the five basic steps of a case-by-case BART
analysis?
1. Step 1: How do I identify all available retrofit emission
control techniques?
2. Step 2: How do I determine whether the options identified in
Step 1 are technically feasible?
3. Step 3: How do I evaluate technically feasible alternatives?
4. Step 4: For a BART review, what impacts am I expected to
calculate and report? What methods does EPA recommend for the
impacts analyses?
a. Impact analysis part 1: how do I estimate the costs of
control?
b. What do we mean by cost effectiveness?
c. How do I calculate average cost effectiveness?
d. How do I calculate baseline emissions?
e. How do I calculate incremental cost effectiveness?
f. What other information should I provide in the cost impacts
analysis?
g. What other things are important to consider in the cost
impacts analysis?
h. Impact analysis part 2: How should I analyze and report
energy impacts?
i. Impact analysis part 3: How do I analyze ``non-air quality
environmental impacts?''
j. Impact analysis part 4: What are examples of non-air quality
environmental impacts?
k. How do I take into account a project's ``remaining useful
life'' in calculating control costs?
5. Step 5: How should I determine visibility impacts in the BART
determination?
E. How do I select the ``best'' alternative, using the results
of Steps 1 through 5?
1. Summary of the impacts analysis
2. Selecting a ``best'' alternative
3. In selecting a ``best'' alternative, should I consider the
affordability of controls?
4. SO2 limits for utility boilers
5. NOX limits for utility boilers
V. Enforceable Limits/Compliance Date
I. Introduction and Overview
A. What is the purpose of the guidelines?
The Clean Air Act (CAA), in sections 169A and 169B, contains
requirements for the protection of visibility in 156 scenic areas
across the United States. To meet the CAA's requirements, we
published regulations to protect against a particular type of
visibility impairment known as ``regional haze.'' The regional haze
rule is found in this part at 40 CFR 51.300 through 51.309. These
regulations require, in 40 CFR 51.308(e), that certain types of
existing stationary sources of air pollutants install best available
retrofit technology (BART). The guidelines are designed to help
States and others (1) identify those sources that must comply with
the BART requirement, and (2) determine the level of control
technology that represents BART for each source.
B. What does the CAA require generally for improving visibility?
Section 169A of the CAA, added to the CAA by the 1977
amendments, requires States to protect and improve visibility in
certain scenic areas of national importance. The scenic areas
protected by section 169A are ``the mandatory Class I Federal Areas
* * * where visibility is an important value.'' In these guidelines,
we refer to these as ``Class I areas.'' There are 156 Class I areas,
including 47 national parks (under the jurisdiction of the
Department of Interior--National Park Service), 108 wilderness areas
(under the jurisdiction of the Department of the Interior--Fish and
Wildlife Service or the Department of Agriculture--U.S. Forest
Service), and one International Park (under the jurisdiction of the
Roosevelt-Campobello International Commission). The Federal Agency
with jurisdiction over a particular Class I area is referred to in
the CAA as the Federal Land Manager. A complete list of the Class I
areas is contained in 40 CFR 81.401 through 81.437, and you can find
a map of the Class I areas at the following Internet site: http://www.epa.gov/ttn/oarpg/t1/fr_notices/classimp.gif.
The CAA establishes a national goal of eliminating man-made
visibility impairment from all Class I areas. As part of the plan
for achieving this goal, the visibility protection provisions in the
CAA mandate that EPA issue regulations requiring that States adopt
measures in their State implementation plans (SIPs), including long-
term strategies, to provide for reasonable progress towards this
national goal. The CAA also requires States to coordinate with the
Federal Land Managers as they develop their strategies for
addressing visibility.
C. What is the BART requirement in the CAA?
1. Under section 169A(b)(2)(A) of the CAA, States must require
certain existing stationary sources to install BART. The BART
provision applies to ``major stationary sources'' from 26 identified
source categories which have the potential to emit 250 tons per year
or more of any air pollutant. The CAA requires only sources which
were put in place during a specific 15-year time interval to be
subject to BART. The BART provision applies to sources that existed
as of the date of the 1977 CAA amendments (that is, August 7, 1977)
but which had not been in operation for more than 15 years (that is,
not in operation as of August 7, 1962).
2. The CAA requires BART review when any source meeting the
above description ``emits any air pollutant which may reasonably be
anticipated to cause or contribute to any impairment of visibility''
in any Class I area. In identifying a level of control as BART,
States are required by section 169A(g) of the CAA to consider:
(a) The costs of compliance,
(b) The energy and non-air quality environmental impacts of
compliance,
(c) Any existing pollution control technology in use at the
source,
(d) The remaining useful life of the source, and
(e) The degree of visibility improvement which may reasonably be
anticipated from the use of BART.
3. The CAA further requires States to make BART emission
limitations part of their SIPs. As with any SIP revision, States
must provide an opportunity for public comment on the BART
determinations, and EPA's action on any SIP revision will be subject
to judicial review.
D. What types of visibility problems does EPA address in its
regulations?
1. We addressed the problem of visibility in two phases. In
1980, we published regulations addressing what we termed
``reasonably attributable'' visibility impairment. Reasonably
attributable visibility impairment is the result of emissions from
one or a few sources that are generally located in close proximity
to a specific Class I area. The regulations addressing reasonably
attributable visibility impairment are published in 40 CFR 51.300
through 51.307.
2. On July 1, 1999, we amended these regulations to address the
second, more common, type of visibility impairment known as
``regional haze.'' Regional haze is the result of the collective
contribution of many sources over a broad region. The regional haze
rule slightly modified 40 CFR 51.300 through 51.307, including the
addition of a few definitions in Sec. 51.301, and added new
Sec. Sec. 51.308 and 51.309.
E. What are the BART requirements in EPA's regional haze
regulations?
1. In the July 1, 1999 rulemaking, we added a BART requirement
for regional haze. We amended the BART requirements in 2005. You
will find the BART requirements in 40 CFR 51.308(e). Definitions of
terms used in 40 CFR 51.308(e)(1) are found in 40 CFR 51.301.
2. As we discuss in detail in these guidelines, the regional
haze rule codifies and clarifies the BART provisions in the CAA. The
rule requires that States identify and list ``BART-eligible
sources,'' that is, that States identify and list those sources that
fall within the 26 source categories, were put in place during the
15-year window of time from 1962 to 1977, and have potential
[[Page 39158]]
emissions greater than 250 tons per year. Once the State has
identified the BART-eligible sources, the next step is to identify
those BART-eligible sources that may ``emit any air pollutant which
may reasonably be anticipated to cause or contribute to any
impairment of visibility.'' Under the rule, a source which fits this
description is ``subject to BART.'' For each source subject to BART,
40 CFR 51.308(e)(1)(ii)(A) requires that States identify the level
of control representing BART after considering the factors set out
in CAA section 169A(g), as follows:
--States must identify the best system of continuous emission
control technology for each source subject to BART taking into
account the technology available, the costs of compliance, the
energy and non-air quality environmental impacts of compliance, any
pollution control equipment in use at the source, the remaining
useful life of the source, and the degree of visibility improvement
that may be expected from available control technology.
3. After a State has identified the level of control
representing BART (if any), it must establish an emission limit
representing BART and must ensure compliance with that requirement
no later than 5 years after EPA approves the SIP. States may
establish design, equipment, work practice or other operational
standards when limitations on measurement technologies make emission
standards infeasible.
F. What is included in the guidelines?
1. The guidelines provide a process for making BART
determinations that States can use in implementing the regional haze
BART requirements on a source-by-source basis, as provided in 40 CFR
51.308(e)(1). States must follow the guidelines in making BART
determinations on a source-by-source basis for 750 megawatt (MW)
power plants but are not required to use the process in the
guidelines when making BART determinations for other types of
sources.
2. The BART analysis process, and the contents of these
guidelines, are as follows:
(a) Identification of all BART-eligible sources. Section II of
these guidelines outlines a step-by-step process for identifying
BART-eligible sources.
(b) Identification of sources subject to BART. As noted above,
sources ``subject to BART'' are those BART-eligible sources which
``emit a pollutant which may reasonably be anticipated to cause or
contribute to any impairment of visibility in any Class I area.'' We
discuss considerations for identifying sources subject to BART in
section III of the guidance.
(c) The BART determination process. For each source subject to
BART, the next step is to conduct an analysis of emissions control
alternatives. This step includes the identification of available,
technically feasible retrofit technologies, and for each technology
identified, an analysis of the cost of compliance, the energy and
non-air quality environmental impacts, and the degree of visibility
improvement in affected Class I areas resulting from the use of the
control technology. As part of the BART analysis, the State should
also take into account the remaining useful life of the source and
any existing control technology present at the source. For each
source, the State will determine a ``best system of continuous
emission reduction'' based upon its evaluation of these factors.
Procedures for the BART determination step are described in section
IV of these guidelines.
(d) Emissions limits. States must establish emission limits,
including a deadline for compliance, consistent with the BART
determination process for each source subject to BART.
Considerations related to these limits are discussed in section V of
these guidelines.
G. Who is the target audience for the guidelines?
1. The guidelines are written primarily for the benefit of
State, local and Tribal agencies, and describe a process for making
the BART determinations and establishing the emission limitations
that must be included in their SIPs or Tribal implementation plans
(TIPs). Throughout the guidelines, which are written in a question
and answer format, we ask questions ``How do I * * *? '' and answer
with phrases ``you should * * *, you must * * * '' The ``you'' means
a State, local or Tribal agency conducting the analysis. We have
used this format to make the guidelines simpler to understand, but
we recognize that States have the authority to require source owners
to assume part of the analytical burden, and that there will be
differences in how the supporting information is collected and
documented. We also recognize that data collection, analysis, and
rule development may be performed by Regional Planning
Organizations, for adoption within each SIP or TIP.
2. The preamble to the 1999 regional haze rule discussed at
length the issue of Tribal implementation of the requirements to
submit a plan to address visibility. As explained there,
requirements related to visibility are among the programs for which
Tribes may be determined eligible and receive authorization to
implement under the ``Tribal Authority Rule'' (``TAR'') (40 CFR 49.1
through 49.11). Tribes are not subject to the deadlines for
submitting visibility implementation plans and may use a modular
approach to CAA implementation. We believe there are very few BART-
eligible sources located on Tribal lands. Where such sources exist,
the affected Tribe may apply for delegation of implementation
authority for this rule, following the process set forth in the TAR.
H. Do EPA regulations require the use of these guidelines?
Section 169A(b) requires us to issue guidelines for States to
follow in establishing BART emission limitations for fossil-fuel
fired power plants having a capacity in excess of 750 megawatts.
This document fulfills that requirement, which is codified in 40 CFR
51.308(e)(1)(ii)(B). The guidelines establish an approach to
implementing the requirements of the BART provisions of the regional
haze rule; we believe that these procedures and the discussion of
the requirements of the regional haze rule and the CAA should be
useful to the States. For sources other than 750 MW power plants,
however, States retain the discretion to adopt approaches that
differ from the guidelines.
II. How to Identify BART-Eligible Sources
This section provides guidelines on how to identify BART-
eligible sources. A BART-eligible source is an existing stationary
source in any of 26 listed categories which meets criteria for
startup dates and potential emissions.
A. What are the steps in identifying BART-eligible sources?
Figure 1 shows the steps for identifying whether the source is a
``BART-eligible source:''
Step 1: Identify the emission units in the BART categories,
Step 2: Identify the start-up dates of those emission units, and
Step 3: Compare the potential emissions to the 250 ton/yr
cutoff.
Figure 1. How to determine whether a source is BART-eligible:
Step 1: Identify emission units in the BART categories
Does the plant contain emissions units in one or more of the 26
source categories?
[rtarr2] No [rtarr2] Stop
[rtarr2] Yes [rtarr2] Proceed to Step 2
Step 2: Identify the start-up dates of these emission units
Do any of these emissions units meet the following two tests?
In existence on August 7, 1977
AND
Began operation after August 7, 1962
[rtarr2] No [rtarr2] Stop
[rtarr2] Yes [rtarr2] Proceed to Step 3
Step 3: Compare the potential emissions from these emission
units to the 250 ton/yr cutoff
Identify the ``stationary source'' that includes the emission
units you identified in Step 2.
Add the current potential emissions from all the emission units
identified in Steps 1 and 2 that are included within the
``stationary source'' boundary.
Are the potential emissions from these units 250 tons per year
or more for any visibility-impairing pollutant?
[rtarr2] No [rtarr2] Stop
[rtarr2] Yes [rtarr2] These emissions units comprise the
``BART-eligible source.''
1. Step 1: Identify Emission Units in the BART Categories
1. The BART requirement only applies to sources in specific
categories listed in the CAA. The BART requirement does not apply to
sources in other source categories, regardless of their emissions.
The listed categories are:
(1) Fossil-fuel fired steam electric plants of more than 250
million British thermal units (BTU) per hour heat input,
(2) Coal cleaning plants (thermal dryers),
(3) Kraft pulp mills,
(4) Portland cement plants,
(5) Primary zinc smelters,
(6) Iron and steel mill plants,
(7) Primary aluminum ore reduction plants,
[[Page 39159]]
(8) Primary copper smelters,
(9) Municipal incinerators capable of charging more than 250
tons of refuse per day,
(10) Hydrofluoric, sulfuric, and nitric acid plants,
(11) Petroleum refineries,
(12) Lime plants,
(13) Phosphate rock processing plants,
(14) Coke oven batteries,
(15) Sulfur recovery plants,
(16) Carbon black plants (furnace process),
(17) Primary lead smelters,
(18) Fuel conversion plants,
(19) Sintering plants,
(20) Secondary metal production facilities,
(21) Chemical process plants,
(22) Fossil-fuel boilers of more than 250 million BTUs per hour
heat input,
(23) Petroleum storage and transfer facilities with a capacity
exceeding 300,000 barrels,
(24) Taconite ore processing facilities,
(25) Glass fiber processing plants, and
(26) Charcoal production facilities.
2. Some plants may have emission units from more than one
category, and some emitting equipment may fit into more than one
category. Examples of this situation are sulfur recovery plants at
petroleum refineries, coke oven batteries and sintering plants at
steel mills, and chemical process plants at refineries. For Step 1,
you identify all of the emissions units at the plant that fit into
one or more of the listed categories. You do not identify emission
units in other categories.
Example: A mine is collocated with an electric steam generating
plant and a coal cleaning plant. You would identify emission units
associated with the electric steam generating plant and the coal
cleaning plant, because they are listed categories, but not the
mine, because coal mining is not a listed category.
3. The category titles are generally clear in describing the
types of equipment to be listed. Most of the category titles are
very broad descriptions that encompass all emission units associated
with a plant site (for example, ``petroleum refining'' and ``kraft
pulp mills''). This same list of categories appears in the PSD
regulations. States and source owners need not revisit any
interpretations of the list made previously for purposes of the PSD
program. We provide the following clarifications for a few of the
category titles:
(1) ``Steam electric plants of more than 250 million BTU/hr heat
input.'' Because the category refers to ``plants,'' we interpret
this category title to mean that boiler capacities should be
aggregated to determine whether the 250 million BTU/hr threshold is
reached. This definition includes only those plants that generate
electricity for sale. Plants that cogenerate steam and electricity
also fall within the definition of ``steam electric plants''.
Similarly, combined cycle turbines are also considered ``steam
electric plants'' because such facilities incorporate heat recovery
steam generators. Simple cycle turbines, in contrast, are not
``steam electric plants'' because these turbines typically do not
generate steam.
Example: A stationary source includes a steam electric plant
with three 100 million BTU/hr boilers. Because the aggregate
capacity exceeds 250 million BTU/hr for the ``plant,'' these boilers
would be identified in Step 2.
(2) ``Fossil-fuel boilers of more than 250 million BTU/hr heat
input.'' We interpret this category title to cover only those
boilers that are individually greater than 250 million BTU/hr.
However, an individual boiler smaller than 250 million BTU/hr should
be subject to BART if it is an integral part of a process
description at a plant that is in a different BART category--for
example, a boiler at a Kraft pulp mill that, in addition to
providing steam or mechanical power, uses the waste liquor from the
process as a fuel. In general, if the process uses any by-product of
the boiler and the boiler's function is to serve the process, then
the boiler is integral to the process and should be considered to be
part of the process description.
Also, you should consider a multi-fuel boiler to be a ``fossil-
fuel boiler'' if it burns any amount of fossil fuel. You may take
federally and State enforceable operational limits into account in
determining whether a multi-fuel boiler's fossil fuel capacity
exceeds 250 million Btu/hr.
(3) ``Petroleum storage and transfer facilities with a capacity
exceeding 300,000 barrels.'' The 300,000 barrel cutoff refers to
total facility-wide tank capacity for tanks that were put in place
within the 1962-1977 time period, and includes gasoline and other
petroleum-derived liquids.
(4) ``Phosphate rock processing plants.'' This category
descriptor is broad, and includes all types of phosphate rock
processing facilities, including elemental phosphorous plants as
well as fertilizer production plants.
(5) ``Charcoal production facilities.'' We interpret this
category to include charcoal briquet manufacturing and activated
carbon production.
(6) ``Chemical process plants.'' and pharmaceutical
manufacturing. Consistent with past policy, we interpret the
category ``chemical process plants'' to include those facilities
within the 2-digit Standard Industrial Classification (SIC) code 28.
Accordingly, we interpret the term ``chemical process plants'' to
include pharmaceutical manufacturing facilities.
(7) ``Secondary metal production.'' We interpret this category
to include nonferrous metal facilities included within SIC code
3341, and secondary ferrous metal facilities that we also consider
to be included within the category ``iron and steel mill plants.''
(8) ``Primary aluminum ore reduction.'' We interpret this
category to include those facilities covered by 40 CFR 60.190, the
new source performance standard (NSPS) for primary aluminum ore
reduction plants. This definition is also consistent with the
definition at 40 CFR 63.840.
2. Step 2: Identify the Start-Up Dates of the Emission Units
1. Emissions units listed under Step 1 are BART-eligible only if
they were ``in existence'' on August 7, 1977 but were not ``in
operation'' before August 7, 1962.
What does ``in existence on August 7, 1977'' mean?
2. The regional haze rule defines ``in existence'' to mean that:
``the owner or operator has obtained all necessary
preconstruction approvals or permits required by Federal, State, or
local air pollution emissions and air quality laws or regulations
and either has (1) begun, or caused to begin, a continuous program
of physical on-site construction of the facility or (2) entered into
binding agreements or contractual obligations, which cannot be
canceled or modified without substantial loss to the owner or
operator, to undertake a program of construction of the facility to
be completed in a reasonable time.'' 40 CFR 51.301.
As this definition is essentially identical to the definition of
``commence construction'' as that term is used in the PSD
regulations, the two terms mean the same thing. See 40 CFR
51.165(a)(1)(xvi) and 40 CFR 52.21(b)(9). Under this definition, an
emissions unit could be ``in existence'' even if it did not begin
operating until several years after 1977.
Example: The owner of a source obtained all necessary permits in
early 1977 and entered into binding construction agreements in June
1977. Actual on-site construction began in late 1978, and
construction was completed in mid-1979. The source began operating
in September 1979. The emissions unit was ``in existence'' as of
August 7, 1977.
Major stationary sources which commenced construction AFTER
August 7, 1977 (i.e., major stationary sources which were not ``in
existence'' on August 7, 1977) were subject to new source review
(NSR) under the PSD program. Thus, the August 7, 1977 ``in
existence'' test is essentially the same thing as the identification
of emissions units that were grandfathered from the NSR review
requirements of the 1977 CAA amendments.
3. Sources are not BART-eligible if the only change at the plant
during the relevant time period was the addition of pollution
controls. For example, if the only change at a copper smelter during
the 1962 through 1977 time period was the addition of acid plants
for the reduction of SO2 emissions, these emission
controls would not by themselves trigger a BART review.
What does ``in operation before August 7, 1962'' mean?
An emissions unit that meets the August 7, 1977 ``in existence''
test is not BART-eligible if it was in operation before August 7,
1962. ``In operation'' is defined as ``engaged in activity related
to the primary design function of the source.'' This means that a
source must have begun actual operations by August 7, 1962 to
satisfy this test.
Example: The owner or operator entered into binding agreements
in 1960. Actual on-site construction began in 1961, and construction
was complete in mid-1962. The source began operating in September
1962. The emissions unit was not ``in operation'' before August 7,
1962 and is therefore subject to BART.
What is a ``reconstructed source?'
1. Under a number of CAA programs, an existing source which is
completely or
[[Page 39160]]
substantially rebuilt is treated as a new source. Such
``reconstructed'' sources are treated as new sources as of the time
of the reconstruction. Consistent with this overall approach to
reconstructions, the definition of BART-eligible facility (reflected
in detail in the definition of ``existing stationary facility'')
includes consideration of sources that were in operation before
August 7, 1962, but were reconstructed during the August 7, 1962 to
August 7, 1977 time period.
2. Under the regional haze regulations at 40 CFR 51.301, a
reconstruction has taken place if ``the fixed capital cost of the
new component exceeds 50 percent of the fixed capital cost of a
comparable entirely new source.'' The rule also states that ``[a]ny
final decision as to whether reconstruction has occurred must be
made in accordance with the provisions of Sec. Sec. 60.15 (f)(1)
through (3) of this title.'' ``[T]he provisions of Sec. Sec.
60.15(f)(1) through (3)'' refers to the general provisions for New
Source Performance Standards (NSPS). Thus, the same policies and
procedures for identifying reconstructed ``affected facilities''
under the NSPS program must also be used to identify reconstructed
``stationary sources'' for purposes of the BART requirement.
3. You should identify reconstructions on an emissions unit
basis, rather than on a plantwide basis. That is, you need to
identify only the reconstructed emission units meeting the 50
percent cost criterion. You should include reconstructed emission
units in the list of emission units you identified in Step 1. You
need consider as possible reconstructions only those emissions units
with the potential to emit more than 250 tons per year of any
visibility-impairing pollutant.
4. The ``in operation'' and ``in existence'' tests apply to
reconstructed sources. If an emissions unit was reconstructed and
began actual operation before August 7, 1962, it is not BART-
eligible. Similarly, any emissions unit for which a reconstruction
``commenced'' after August 7, 1977, is not BART-eligible.
How are modifications treated under the BART provision?
1. The NSPS program and the major source NSR program both
contain the concept of modifications. In general, the term
``modification'' refers to any physical change or change in the
method of operation of an emissions unit that results in an increase
in emissions.
2. The BART provision in the regional haze rule contains no
explicit treatment of modifications or how modified emissions units,
previously subject to the requirement to install best available
control technology (BACT), lowest achievable emission rate (LAER)
controls, and/or NSPS are treated under the rule. As the BART
requirements in the CAA do not appear to provide any exemption for
sources which have been modified since 1977, the best interpretation
of the CAA visibility provisions is that a subsequent modification
does not change a unit's construction date for the purpose of BART
applicability. Accordingly, if an emissions unit began operation
before 1962, it is not BART-eligible if it was modified between 1962
and 1977, so long as the modification is not also a
``reconstruction.'' On the other hand, an emissions unit which began
operation within the 1962-1977 time window, but was modified after
August 7, 1977, is BART-eligible. We note, however, that if such a
modification was a major modification that resulted in the
installation of controls, the State will take this into account
during the review process and may find that the level of controls
already in place are consistent with BART.
3. Step 3: Compare the Potential Emissions to the 250 Ton/Yr Cutoff
The result of Steps 1 and 2 will be a list of emissions units at
a given plant site, including reconstructed emissions units, that
are within one or more of the BART categories and that were placed
into operation within the 1962-1977 time window. The third step is
to determine whether the total emissions represent a current
potential to emit that is greater than 250 tons per year of any
single visibility impairing pollutant. Fugitive emissions, to the
extent quantifiable, must be counted. In most cases, you will add
the potential emissions from all emission units on the list
resulting from Steps 1 and 2. In a few cases, you may need to
determine whether the plant contains more than one ``stationary
source'' as the regional haze rule defines that term, and as we
explain further below.
What pollutants should I address?
Visibility-impairing pollutants include the following:
(1) Sulfur dioxide (SO2),
(2) Nitrogen oxides (NOX), and
(3) Particulate matter.
You may use PM10 as an indicator for particulate
matter in this intial step. [Note that we do not recommend use of
total suspended particulates (TSP) as in indicator for particulate
matter.] As emissions of PM10 include the components of
PM2.5 as a subset, there is no need to have separate 250
ton thresholds for PM10 and PM2.5; 250 tons of
PM10 represents at most 250 tons of PM2.5, and
at most 250 tons of any individual particulate species such as
elemental carbon, crustal material, etc.
However, if you determine that a source of particulate matter is
BART-eligible, it will be important to distinguish between the fine
and coarse particle components of direct particulate emissions in
the remainder of the BART analysis, including for the purpose of
modeling the source's impact on visibility. This is because although
both fine and coarse particulate matter contribute to visibility
impairment, the long-range transport of fine particles is of
particular concern in the formation of regional haze. Thus, for
example, air quality modeling results used in the BART determination
will provide a more accurate prediction of a source's impact on
visibility if the inputs into the model account for the relative
particle size of any directly emitted particulate matter (i.e.
PM10 vs. PM2.5).
You should exercise judgment in deciding whether the following
pollutants impair visibility in an area:
(4) Volatile organic compounds (VOC), and
(5) Ammonia and ammonia compounds.
You should use your best judgment in deciding whether VOC or
ammonia emissions from a source are likely to have an impact on
visibility in an area. Certain types of VOC emissions, for example,
are more likely to form secondary organic aerosols than others.\1\
Similarly, controlling ammonia emissions in some areas may not have
a significant impact on visibility. You need not provide a formal
showing of an individual decision that a source of VOC or ammonia
emissions is not subject to BART review. Because air quality
modeling may not be feasible for individual sources of VOC or
ammonia, you should also exercise your judgement in assessing the
degree of visibility impacts due to emissions of VOC and emissions
of ammonia or ammonia compounds. You should fully document the basis
for judging that a VOC or ammonia source merits BART review,
including your assessment of the source's contribution to visibility
impairment.
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\1\ Fine particles: Overview of Atmospheric Chemistry, Sources
of Emissions, and Ambient Monitoring Data, Memorandum to Docket OAR
2002-006, April 1, 2005.
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What does the term ``potential'' emissions mean?
The regional haze rule defines potential to emit as follows:
``Potential to emit'' means the maximum capacity of a stationary
source to emit a pollutant under its physical and operational
design. Any physical or operational limitation on the capacity of
the source to emit a pollutant including air pollution control
equipment and restrictions on hours of operation or on the type or
amount of material combusted, stored, or processed, shall be treated
as part of its design if the limitation or the effect it would have
on emissions is federally enforceable. Secondary emissions do not
count in determining the potential to emit of a stationary source.
The definition of ``potential to emit'' means that a source which
actually emits less than 250 tons per year of a visibility-impairing
pollutant is BART-eligible if its emissions would exceed 250 tons
per year when operating at its maximum capacity given its physical
and operational design (and considering all federally enforceable
and State enforceable permit limits.)
Example: A source, while operating at one-fourth of its
capacity, emits 75 tons per year of SO2. If it were
operating at 100 percent of its maximum capacity, the source would
emit 300 tons per year. Because under the above definition such a
source would have ``potential'' emissions that exceed 250 tons per
year, the source (if in a listed category and built during the 1962-
1977 time window) would be BART-eligible.
How do I identify whether a plant has more than one ``stationary
source?''
1. The regional haze rule, in 40 CFR 51.301, defines a
stationary source as a ``building, structure, facility or
installation which emits or may emit any air pollutant.'' \2\
[[Page 39161]]
The rule further defines ``building, structure or facility'' as:
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\2\ Note: Most of these terms and definitions are the same for
regional haze and the 1980 visibility regulations. For the regional
haze rule we use the term ``BART-eligible source'' rather than
``existing stationary facility'' to clarify that only a limited
subset of existing stationary sources are subject to BART.
all of the pollutant-emitting activities which belong to the same
industrial grouping, are located on one or more contiguous or
adjacent properties, and are under the control of the same person
(or persons under common control). Pollutant-emitting activities
must be considered as part of the same industrial grouping if they
belong to the same Major Group (i.e., which have the same two-digit
code) as described in the Standard Industrial Classification Manual,
1972 as amended by the 1977 Supplement (U.S. Government Printing
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Office stock numbers 4101-0066 and 003-005-00176-0, respectively).
2. In applying this definition, it is necessary to determine
which facilities are located on ``contiguous or adjacent
properties.'' Within this contiguous and adjacent area, it is also
necessary to group those emission units that are under ``common
control.'' We note that these plant boundary issues and ``common
control'' issues are very similar to those already addressed in
implementation of the title V operating permits program and in NSR.
3. For emission units within the ``contiguous or adjacent''
boundary and under common control, you must group emission units
that are within the same industrial grouping (that is, associated
with the same 2-digit SIC code) in order to define the stationary
source.\3\ For most plants on the BART source category list, there
will only be one 2-digit SIC that applies to the entire plant. For
example, all emission units associated with kraft pulp mills are
within SIC code 26, and chemical process plants will generally
include emission units that are all within SIC code 28. The ``2-
digit SIC test'' applies in the same way as the test is applied in
the major source NSR programs.\4\
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\3\ We recognize that we are in a transition period from the use
of the SIC system to a new system called the North American Industry
Classification System (NAICS). For purposes of identifying BART-
eligible sources, you may use either 2-digit SICS or the equivalent
in the NAICS system.
\4\ Note: The concept of support facility used for the NSR
program applies here as well. Support facilities, that is facilities
that convey, store or otherwise assist in the production of the
principal product, must be grouped with primary facilities even when
the facilities fall wihin separate SIC codes. For purposes of BART
reviews, however, such support facilities (a) must be within one of
the 26 listed source categories and (b) must have been in existence
as of August 7, 1977, and (c) must not have been in operation as of
August 7, 1962.
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4. For purposes of the regional haze rule, you must group
emissions from all emission units put in place within the 1962-1977
time period that are within the 2-digit SIC code, even if those
emission units are in different categories on the BART category
list.
Examples: A chemical plant which started operations within the
1962 to 1977 time period manufactures hydrochloric acid (within the
category title ``Hydrochloric, sulfuric, and nitric acid plants'')
and various organic chemicals (within the category title ``chemical
process plants''). All of the emission units are within SIC code 28
and, therefore, all the emission units are considered in determining
BART eligibility of the plant. You sum the emissions over all of
these emission units to see whether there are more than 250 tons per
year of potential emissions.
A steel mill which started operations within the 1962 to 1977
time period includes a sintering plant, a coke oven battery, and
various other emission units. All of the emission units are within
SIC code 33. You sum the emissions over all of these emission units
to see whether there are more than 250 tons per year of potential
emissions.
4. Final Step: Identify the Emissions Units and Pollutants That
Constitute the BART-Eligible Source
If the emissions from the list of emissions units at a
stationary source exceed a potential to emit of 250 tons per year
for any visibility-impairing pollutant, then that collection of
emissions units is a BART-eligible source.
Example: A stationary source comprises the following two
emissions units, with the following potential emissions:
Emissions unit A
200 tons/yr SO2
150 tons/yr NOX
25 tons/yr PM
Emissions unit B
100 tons/yr SO2
75 tons/yr NOX
10 tons/yr PM
For this example, potential emissions of SO2 are 300
tons/yr, which exceeds the 250 tons/yr threshold. Accordingly, the
entire ``stationary source'', that is, emissions units A and B, may
be subject to a BART review for SO2, NOX, and
PM, even though the potential emissions of PM and NOX at
each emissions unit are less than 250 tons/yr each.
Example: The total potential emissions, obtained by adding the
potential emissions of all emission units in a listed category at a
plant site, are as follows:
200 tons/yr SO2
150 tons/yr NOX
25 tons/yr PM
Even though total emissions exceed 250 tons/yr, no individual
regulated pollutant exceeds 250 tons/yr and this source is not BART-
eligible.
Can States establish de minimis levels of emissions for pollutants at
BART-eligible sources?
In order to simplify BART determinations, States may choose to
identify de minimis levels of pollutants at BART-eligible sources
(but are not required to do so). De minimis values should be
identified with the purpose of excluding only those emissions so
minimal that they are unlikely to contribute to regional haze. Any
de minimis values that you adopt must not be higher than the PSD
applicability levels: 40 tons/yr for SO2 and
NOX and 15 tons/yr for PM10. These de minimis
levels may only be applied on a plant-wide basis.
III. How to Identify Sources ``Subject to BART''
Once you have compiled your list of BART-eligible sources, you
need to determine whether (1) to make BART determinations for all of
them or (2) to consider exempting some of them from BART because
they may not reasonably be anticipated to cause or contribute to any
visibility impairment in a Class I area. If you decide to make BART
determinations for all the BART-eligible sources on your list, you
should work with your regional planning organization (RPO) to show
that, collectively, they cause or contribute to visibility
impairment in at least one Class I area. You should then make
individual BART determinations by applying the five statutory
factors discussed in Section IV below.
On the other hand, you also may choose to perform an initial
examination to determine whether a particular BART-eligible source
or group of sources causes or contributes to visibility impairment
in nearby Class I areas. If your analysis, or information submitted
by the source, shows that an individual source or group of sources
(or certain pollutants from those sources) is not reasonably
anticipated to cause or contribute to any visibility impairment in a
Class I area, then you do not need to make BART determinations for
that source or group of sources (or for certain pollutants from
those sources). In such a case, the source is not ``subject to
BART'' and you do not need to apply the five statutory factors to
make a BART determination. This section of the Guideline discusses
several approaches that you can use to exempt sources from the BART
determination process.
A. What Steps Do I Follow To Determine Whether a Source or Group of
Sources Cause or Contribute to Visibility Impairment for Purposes
of BART?
1. How Do I Establish a Threshold?
One of the first steps in determining whether sources cause or
contribute to visibility impairment for purposes of BART is to
establish a threshold (measured in deciviews) against which to
measure the visibility impact of one or more sources. A single
source that is responsible for a 1.0 deciview change or more should
be considered to ``cause'' visibility impairment; a source that
causes less than a 1.0 deciview change may still contribute to
visibility impairment and thus be subject to BART.
Because of varying circumstances affecting different Class I
areas, the appropriate threshold for determining whether a source
``contributes to any visibility impairment'' for the purposes of
BART may reasonably differ across States. As a general matter, any
threshold that you use for determining whether a source
``contributes'' to visibility impairment should not be higher than
0.5 deciviews.
In setting a threshold for ``contribution,'' you should consider
the number of emissions sources affecting the Class I areas at issue
and the magnitude of the individual sources' impacts.\5\ In general,
a larger number of sources causing impacts in a Class I area may
warrant a lower contribution threshold. States remain free to use a
threshold lower than 0.5 deciviews if they conclude that the
[[Page 39162]]
location of a large number of BART-eligible sources within the State
and in proximity to a Class I area justify this approach.\6\
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\5\ We expect that regional planning organizations will have
modeling information that identifies sources affecting visibility in
individual class I areas.
\6\ Note that the contribution threshold should be used to
determine whether an individual source is reasonably anticipated to
contribute to visibility impairment. You should not aggregate the
visibility effects of multiple sources and compare their collective
effects against your contribution threshold because this would
inappropriately create a ``contribute to contribution'' test.
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2. What Pollutants Do I Need to Consider?
You must look at SO2, NOX, and direct
particulate matter (PM) emissions in determining whether sources
cause or contribute to visibility impairment, including both
PM10 and PM2.5. Consistent with the approach
for identifying your BART-eligible sources, you do not need to
consider less than de minimis emissions of these pollutants from a
source.
As explained in section II, you must use your best judgement to
determine whether VOC or ammonia emissions are likely to have an
impact on visibility in an area. In addition, although as explained
in Section II, you may use PM10 an indicator for
particulate matter in determining whether a source is BART-eligible,
in determining whether a source contributes to visibility
impairment, you should distinguish between the fine and coarse
particle components of direct particulate emissions. Although both
fine and coarse particulate matter contribute to visibility
impairment, the long-range transport of fine particles is of
particular concern in the formation of regional haze. Air quality
modeling results used in the BART determination will provide a more
accurate prediction of a source's impact on visibility if the inputs
into the model account for the relative particle size of any
directly emitted particulate matter (i.e. PM10 vs.
PM2.5).
3. What Kind of Modeling Should I Use To Determine Which Sources and
Pollutants Need Not Be Subject to BART?
This section presents several options for determining that
certain sources need not be subject to BART. These options rely on
different modeling and/or emissions analysis approaches. They are
provided for your guidance. You may also use other reasonable
approaches for analyzing the visibility impacts of an individual
source or group of sources.
Option 1: Individual Source Attribution Approach (Dispersion
Modeling)
You can use dispersion modeling to determine that an individual
source cannot reasonably be anticipated to cause or contribute to
visibility impairment in a Class I area and thus is not subject to
BART. Under this option, you can analyze an individual source's
impact on visibility as a result of its emissions of SO2,
NOX and direct PM emissions. Dispersion modeling cannot
currently be used to estimate the predicted impacts on visibility
from an individual source's emissions of VOC or ammonia. You may use
a more qualitative assessment to determine on a case-by-case basis
which sources of VOC or ammonia emissions may be likely to impair
visibility and should therefore be subject to BART review, as
explained in section II.A.3. above.
You can use CALPUFF \7\ or other appropriate model to predict
the visibility impacts from a single source at a Class I area.
CALPUFF is the best regulatory modeling application currently
available for predicting a single source's contribution to
visibility impairment and is currently the only EPA-approved model
for use in estimating single source pollutant concentrations
resulting from the long range transport of primary pollutants.\8\ It
can also be used for some other purposes, such as the visibility
assessments addressed in today's rule, to account for the chemical
transformation of SO2 and NOX.
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\7\ The model code and its documentation are available at no
cost for download from http://www.epa.gov/scram001/tt22.htm#calpuff.
\8\ The Guideline on Air Quality Models, 40 CFR part 51,
appendix W, addresses the regulatory application of air quality
models for assessing criteria pollutants under the CAA, and
describes further the procedures for using the CALPUFF model, as
well as for obtaining approval for the use of other, nonguideline
models.
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There are several steps for making an individual source
attribution using a dispersion model:
1. Develop a modeling protocol. Some critical items to include
in the protocol are the meteorological and terrain data that will be
used, as well as the source-specific information (stack height,
temperature, exit velocity, elevation, and emission rates of
applicable pollutants) and receptor data from appropriate Class I
areas. We recommend following EPA's Interagency Workgroup on Air
Quality Modeling (IWAQM) Phase 2 Summary Report and Recommendations
for Modeling Long Range Transport Impacts \9\ for parameter settings
and meteorological data inputs. You may use other settings from
those in IWAQM, but you should identify these settings and explain
your selection of these settings.
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\9\ Interagency Workgroup on Air Quality Modeling (IWAQM) Phase
2 Summary Report and Recommendations for Modeling Long Range
Transport Impacts, U.S. Environmental Protection Agency, EPA-454/R-
98-019, December 1998.
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One important element of the protocol is in establishing the
receptors that will be used in the model. The receptors that you use
should be located in the nearest Class I area with sufficient
density to identify the likely visibility effects of the source. For
other Class I areas in relatively close proximity to a BART-eligible
source, you may model a few strategic receptors to determine whether
effects at those areas may be greater than at the nearest Class I
area. For example, you might chose to locate receptors at these
areas at the closest point to the source, at the highest and lowest
elevation in the Class I area, at the IMPROVE monitor, and at the
approximate expected plume release height. If the highest modeled
effects are observed at the nearest Class I area, you may choose not
to analyze the other Class I areas any further as additional
analyses might be unwarranted.
You should bear in mind that some receptors within the relevant
Class I area may be less than 50 km from the source while other
receptors within that same Class I area may be greater than 50 km
from the same source. As indicated by the Guideline on Air Quality
Models, 40 CFR part 51, appendix W, this situation may call for the
use of two different modeling approaches for the same Class I area
and source, depending upon the State's chosen method for modeling
sources less than 50 km. In situations where you are assessing
visibility impacts for source-receptor distances less than 50 km,
you should use expert modeling judgment in determining visibility
impacts, giving consideration to both CALPUFF and other appropriate
methods.
In developing your modeling protocol, you may want to consult
with EPA and your regional planning organization (RPO). Up-front
consultation will ensure that key technical issues are addressed
before you conduct your modeling.
2. With the accepted protocol and compare the predicted
visibility impacts with your threshold for ``contribution.'' You
should calculate daily visibility values for each receptor as the
change in deciviews compared against natural visibility conditions.
You can use EPA's ``Guidance for Estimating Natural Visibility
Conditions Under the Regional Haze Rule,'' EPA-454/B-03-005
(September 2003) in making this calculation. To determine whether a
source may reasonably be anticipated to cause or contribute to
visibility impairment at Class I area, you then compare the impacts
predicted by the model against the threshold that you have selected.
The emissions estimates used in the models are intended to
reflect steady-state operating conditions during periods of high
capacity utilization. We do not generally recommend that emissions
reflecting periods of start-up, shutdown, and malfunction be used,
as such emission rates could produce higher than normal effects than
would be typical of most facilities. We recommend that States use
the 24 hour average actual emission rate from the highest emitting
day of the meteorological period modeled, unless this rate reflects
periods start-up, shutdown, or malfunction. In addition, the monthly
average relative humidity is used, rather than the daily average
humidity--an approach that effectively lowers the peak values in
daily model averages.
For these reasons, if you use the modeling approach we
recommend, you should compare your ``contribution'' threshold
against the 98th percentile of values. If the 98th percentile value
from your modeling is less than your contribution threshold, then
you may conclude that the source does not contribute to visibility
impairment and is not subject to BART.
Option 2: Use of Model Plants To Exempt Individual Sources With
Common Characteristics
Under this option, analyses of model plants could be used to
exempt certain BART-eligible sources that share specific
characteristics. It may be most useful to use this type of analysis
to identify the types of small sources that do not cause or
contribute to visibility impairment for purposes of BART, and thus
should not be subject to a BART review. Different Class I areas may
have different characteristics, however, so
[[Page 39163]]
you should use care to ensure that the criteria you develop are
appropriate for the applicable cases.
In carrying out this approach, you could use modeling analyses
of representative plants to reflect groupings of specific sources
with important common characteristics. Based on these analyses, you
may find that certain types of sources are clearly anticipated to
cause or contribute to visibility impairment. You could then choose
to categorically require those types of sources to undergo a BART
determination. Conversely, you may find based on representative
plant analyses that certain types of sources are not reasonably
anticipated to cause or contribute to visibility impairment. To do
this, you may conduct your own modeling to establish emission levels
and distances from Class I areas on which you can rely to exempt
sources with those characteristics. For example, based on your
modeling you might choose to exempt all NOX-only sources
that emit less than a certain amount per year and are located a
certain distance from a Class I area. You could then choose to
categorically exempt such sources from the BART determination
process.
Our analyses of visibility impacts from model plants provide a
useful example of the type of analyses that can be used to exempt
categories of sources from BART.\10\ In our analyses, we developed
model plants (EGUs and non-EGUs), with representative plume and
stack characteristics, for use in considering the visibility impact
from emission sources of different sizes and compositions at
distances of 50, 100 and 200 kilometers from two hypothetical Class
I areas (one in the East and one in the West). As the plume and
stack characteristics of these model plants were developed
considering the broad range of sources within the EGU and non-EGU
categories, they do not necessarily represent any specific plant.
However, the results of these analyses are instructive in the
development of an exemption process for any Class I area.
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\10\ CALPUFF Analysis in Support of the June 2005 Changes to the
Regional Haze Rule, U.S. Environmental Protection Agency, June 15,
2005, Docket No. OAR-2002-0076.
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In preparing our analyses, we have made a number of assumptions
and exercised certain modeling choices; some of these have a
tendency to lend conservatism to the results, overstating the likely
effects, while others may understate the likely effects. On balance,
when all of these factors are considered, we believe that our
examples reflect realistic treatments of the situations being
modeled. Based on our analyses, we believe that a State that has
established 0.5 deciviews as a contribution threshold could
reasonably exempt from the BART review process sources that emit
less than 500 tons per year of NOX or SO2 (or
combined NOX and SO2), as long as these
sources are located more than 50 kilometers from any Class I area;
and sources that emit less than 1000 tons per year of NOX
or SO2 (or combined NOX and SO2)
that are located more than 100 kilometers from any Class I area. You
do, however, have the option of showing other thresholds might also
be appropriate given your specific circumstances.
Option 3: Cumulative Modeling To Show That No Sources in a State
Are Subject to BART
You may also submit to EPA a demonstration based on an analysis
of overall visibility impacts that emissions from BART-eligible
sources in your State, considered together, are not reasonably
anticipated to cause or contribute to any visibility impairment in a
Class I area, and thus no source should be subject to BART. You may
do this on a pollutant by pollutant basis or for all visibility-
impairing pollutants to determine if emissions from these sources
contribute to visibility impairment.
For example, emissions of SO2 from your BART-eligible
sources may clearly cause or contribute to visibility impairment
while direct emissions of PM2.5 from these sources may
not contribute to impairment. If you can make such a demonstration,
then you may reasonably conclude that none of your BART-eligible
sources are subject to BART for a particular pollutant or
pollutants. As noted above, your demonstration should take into
account the interactions among pollutants and their resulting
impacts on visibility before making any pollutant-specific
determinations.
Analyses may be conducted using several alternative modeling
approaches. First, you may use the CALPUFF or other appropriate
model as described in Option 1 to evaluate the impacts of individual
sources on downwind Class I areas, aggregating those impacts to
determine the collective contribution of all BART-eligible sources
to visibility impairment. You may also use a photochemical grid
model. As a general matter, the larger the number of sources being
modeled, the more appropriate it may be to use a photochemical grid
model. However, because such models are significantly less sensitive
than dispersion models to the contributions of one or a few sources,
as well as to the interactions among sources that are widely
distributed geographically, if you wish to use a grid model, you
should consult with the appropriate EPA Regional Office to develop
an appropriate modeling protocol.
IV. The BART Determination: Analysis of BART Options
This section describes the process for the analysis of control
options for sources subject to BART.
A. What factors must I address in the BART review?
The visibility regulations define BART as follows:
Best Available Retrofit Technology (BART) means an emission
limitation based on the degree of reduction achievable through the
application of the best system of continuous emission reduction for
each pollutant which is emitted by . . . [a BART-eligible source].
The emission limitation must be established, on a case-by-case
basis, taking into consideration the technology available, the costs
of compliance, the energy and non-air quality environmental impacts
of compliance, any pollution control equipment in use or in
existence at the source, the remaining useful life of the source,
and the degree of improvement in visibility which may reasonably be
anticipated to result from the use of such technology.
The BART analysis identifies the best system of continuous
emission reduction taking into account:
(1) The available retrofit control options,
(2) Any pollution control equipment in use at the source (which
affects the availability of options and their impacts),
(3) The costs of compliance with control options,
(4) The remaining useful life of the facility,
(5) The energy and non-air quality environmental impacts of
control options
(6) The visibility impacts analysis.
B. What is the scope of the BART review?
Once you determine that a source is subject to BART for a
particular pollutant, then for each affected emission unit, you must
establish BART for that pollutant. The BART determination must
address air pollution control measures for each emissions unit or
pollutant emitting activity subject to review.
Example: Plantwide emissions from emission units within the
listed categories that began operation within the ``time window''
for BART \11\ are 300 tons/yr of NOX, 200 tons/yr of
SO2, and 150 tons/yr of primary particulate. Emissions
unit A emits 200 tons/yr of NOX, 100 tons/yr of
SO2, and 100 tons/yr of primary particulate. Other
emission units, units B through H, which began operating in 1966,
contribute lesser amounts of each pollutant. For this example, a
BART review is required for NOX, SO2, and
primary particulate, and control options must be analyzed for units
B through H as well as unit A.
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\11\ That is, emission units that were in existence on August 7,
1977 and which began actual operation on or after August 7, 1962.
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C. How does a BART review relate to Maximum Achievable Control
Technology (MACT) Standards under CAA section 112, or to other
emission limitations required under the CAA?
For VOC and PM sources subject to MACT standards, States may
streamline the analysis by including a discussion of the MACT
controls and whether any major new technologies have been developed
subsequent to the MACT standards. We believe that there are many VOC
and PM sources that are well controlled because they are regulated
by the MACT standards, which EPA developed under CAA section 112.
For a few MACT standards, this may also be true for SO2.
Any source subject to MACT standards must meet a level that is as
stringent as the best-controlled 12 percent of sources in the
industry. Examples of these hazardous air pollutant sources which
effectively control VOC and PM emissions include (among others)
secondary lead facilities, organic chemical plants subject to the
hazardous organic NESHAP (HON), pharmaceutical production
facilities, and equipment leaks and wastewater operations at
petroleum refineries. We believe that, in many cases, it will be
unlikely that States will identify emission controls more stringent
than the MACT standards without
[[Page 39164]]
identifying control options that would cost many thousands of
dollars per ton. Unless there are new technologies subsequent to the
MACT standards which would lead to cost-effective increases in the
level of control, you may rely on the MACT standards for purposes of
BART.
We believe that the same rationale also holds true for emissions
standards developed for municipal waste incinerators under CAA
section 111(d), and for many NSR/PSD determinations and NSR/PSD
settlement agreements. However, we do not believe that technology
determinations from the 1970s or early 1980s, including new source
performance standards (NSPS), should be considered to represent best
control for existing sources, as best control levels for recent
plant retrofits are more stringent than these older levels.
Where you are relying on these standards to represent a BART
level of control, you should provide the public with a discussion of
whether any new technologies have subsequently become available.
D. What Are the Five Basic Steps of a Case-by-Case BART Analysis?
The five steps are:
STEP 1--Identify All \12\ Available Retrofit Control
Technologies,
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\12\ In identifying ``all'' options, you must identify the most
stringent option and a reasonable set of options for analysis that
reflects a comprehensive list of available technologies. It is not
necessary to list all permutations of available control levels that
exist for a given technology--the list is complete if it includes
the maximum level of control each technology is capable of
achieving.
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STEP 2-- Eliminate Technically Infeasible Options,
STEP 3-- Evaluate Control Effectiveness of Remaining Control
Technologies,
STEP 4-- Evaluate Impacts and Document the Results, and
STEP 5--Evaluate Visibility Impacts.
1. STEP 1: How do I identify all available retrofit emission control
techniques?
1. Available retrofit control options are those air pollution
control technologies with a practical potential for application to
the emissions unit and the regulated pollutant under evaluation. Air
pollution control technologies can include a wide variety of
available methods, systems, and techniques for control of the
affected pollutant. Technologies required as BACT or LAER are
available for BART purposes and must be included as control
alternatives. The control alternatives can include not only existing
controls for the source category in question but also take into
account technology transfer of controls that have been applied to
similar source categories and gas streams. Technologies which have
not yet been applied to (or permitted for) full scale operations
need not be considered as available; we do not expect the source
owner to purchase or construct a process or control device that has
not already been demonstrated in practice.
2. Where a NSPS exists for a source category (which is the case
for most of the categories affected by BART), you should include a
level of control equivalent to the NSPS as one of the control
options.\13\ The NSPS standards are codified in 40 CFR part 60. We
note that there are situations where NSPS standards do not require
the most stringent level of available control for all sources within
a category. For example, post-combustion NOX controls
(the most stringent controls for stationary gas turbines) are not
required under subpart GG of the NSPS for Stationary Gas Turbines.
However, such controls must still be considered available
technologies for the BART selection process.
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\13\ In EPA's 1980 BART guidelines for reasonably attributable
visibility impairment, we concluded that NSPS standards generally,
at that time, represented the best level sources could install as
BART. In the 20 year period since this guidance was developed, there
have been advances in SO2 control technologies as well as
technologies for the control of other pollutants, confirmed by a
number of recent retrofits at Western power plants. Accordingly, EPA
no longer concludes that the NSPS level of controls automatically
represents ``the best these sources can install.'' Analysis of the
BART factors could result in the selection of a NSPS level of
control, but you should reach this conclusion only after considering
the full range of control options.
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3. Potentially applicable retrofit control alternatives can be
categorized in three ways.
Pollution prevention: use of inherently lower-emitting
processes/practices, including the use of control techniques (e.g.
low-NOX burners) and work practices that prevent
emissions and result in lower ``production-specific'' emissions
(note that it is not our intent to direct States to switch fuel
forms, e.g. from coal to gas),
Use of (and where already in place, improvement in the
performance of) add-on controls, such as scrubbers, fabric filters,
thermal oxidizers and other devices that control and reduce
emissions after they are produced, and
Combinations of inherently lower-emitting processes and
add-on controls.
4. In the course of the BART review, one or more of the
available control options may be eliminated from consideration
because they are demonstrated to be technically infeasible or to
have unacceptable energy, cost, or non-air quality environmental
impacts on a case-by-case (or site-specific) basis. However, at the
outset, you should initially identify all control options with
potential application to the emissions unit under review.
5. We do not consider BART as a requirement to redesign the
source when considering available control alternatives. For example,
where the source subject to BART is a coal-fired electric generator,
we do not require the BART analysis to consider building a natural
gas-fired electric turbine although the turbine may be inherently
less polluting on a per unit basis.
6. For emission units subject to a BART review, there will often
be control measures or devices already in place. For such emission
units, it is important to include control options that involve
improvements to existing controls and not to limit the control
options only to those measures that involve a complete replacement
of control devices.
Example: For a power plant with an existing wet scrubber, the
current control efficiency is 66 percent. Part of the reason for the
relatively low control efficiency is that 22 percent of the gas
stream bypasses the scrubber. A BART review identifies options for
improving the performance of the wet scrubber by redesigning the
internal components of the scrubber and by eliminating or reducing
the percentage of the gas stream that bypasses the scrubber. Four
control options are identified: (1) 78 percent control based upon
improved scrubber performance while maintaining the 22 percent
bypass, (2) 83 percent control based upon improved scrubber
performance while reducing the bypass to 15 percent, (3) 93 percent
control based upon improving the scrubber performance while
eliminating the bypass entirely, (this option results in a ``wet
stack'' operation in which the gas leaving the stack is saturated
with water) and (4) 93 percent as in option 3, with the addition of
an indirect reheat system to reheat the stack gas above the
saturation temperature. You must consider each of these four options
in a BART analysis for this source.
7. You are expected to identify potentially applicable retrofit
control technologies that represent the full range of demonstrated
alternatives. Examples of general information sources to consider
include:
The EPA's Clean Air Technology Center, which includes
the RACT/BACT/LAER Clearinghouse (RBLC);
State and Local Best Available Control Technology
Guidelines--many agencies have online information--for example South
Coast Air Quality Management District, Bay Area Air Quality
Management District, and Texas Natural Resources Conservation
Commission;
Control technology vendors;
Federal/State/Local NSR permits and associated
inspection/performance test reports;
Environmental consultants;
Technical journals, reports and newsletters, air
pollution control seminars; and
The EPA's NSR bulletin board--http://www.epa.gov/ttn/nsr;
Department of Energy's Clean Coal Program--technical
reports;
The NOX Control Technology ``Cost Tool''--
Clean Air Markets Division Web page--http://www.epa.gov/airmarkets/arp/nox/controltech.html;
Performance of selective catalytic reduction on coal-
fired steam generating units--final report. OAR/ARD, June 1997 (also
available at http://www.epa.gov/airmarkets/arp/nox/controltech.html);
Cost estimates for selected applications of
NOX control technologies on stationary combustion
boilers. OAR/ARD June 1997. (Docket for NOX SIP Call, A-
96-56, item II-A-03);
Investigation of performance and cost of NOX
controls as applied to group 2 boilers. OAR/ARD, August 1996.
(Docket for Phase II NOX rule, A-95-28, item IV-A-4);
Controlling SO2 Emissions: A Review of
Technologies. EPA-600/R-00-093, USEPA/ORD/NRMRL, October 2000; and
The OAQPS Control Cost Manual.
You are expected to compile appropriate information from these
information sources.
8. There may be situations where a specific set of units within
a fenceline constitutes the
[[Page 39165]]
logical set to which controls would apply and that set of units may
or may not all be BART-eligible. (For example, some units in that
set may not have been constructed between 1962 and 1977.)
9. If you find that a BART source has controls already in place
which are the most stringent controls available (note that this
means that all possible improvements to any control devices have
been made), then it is not necessary to comprehensively complete
each following step of the BART analysis in this section. As long
these most stringent controls available are made federally
enforceable for the purpose of implementing BART for that source,
you may skip the remaining analyses in this section, including the
visibility analysis in step 5. Likewise, if a source commits to a
BART determination that consists of the most stringent controls
available, then there is no need to complete the remaining analyses
in this section.
2. STEP 2: How do I determine whether the options identified in Step 1
are technically feasible?
In Step 2, you evaluate the technical feasibility of the control
options you identified in Step 1. You should document a
demonstration of technical infeasibility and should explain, based
on physical, chemical, or engineering principles, why technical
difficulties would preclude the successful use of the control option
on the emissions unit under review. You may then eliminate such
technically infeasible control options from further consideration in
the BART analysis.
In general, what do we mean by technical feasibility?
Control technologies are technically feasible if either (1) they
have been installed and operated successfully for the type of source
under review under similar conditions, or (2) the technology could
be applied to the source under review. Two key concepts are
important in determining whether a technology could be applied:
``availability'' and ``applicability.'' As explained in more detail
below, a technology is considered ``available'' if the source owner
may obtain it through commercial channels, or it is otherwise
available within the common sense meaning of the term. An available
technology is ``applicable'' if it can reasonably be installed and
operated on the source type under consideration. A technology that
is available and applicable is technically feasible.
What do we mean by ``available'' technology?
1. The typical stages for bringing a control technology concept
to reality as a commercial product are:
Concept stage;
Research and patenting;
Bench scale or laboratory testing;
Pilot scale testing;
Licensing and commercial demonstration; and
Commercial sales.
2. A control technique is considered available, within the
context presented above, if it has reached the stage of licensing
and commercial availability. Similarly, we do not expect a source
owner to conduct extended trials to learn how to apply a technology
on a totally new and dissimilar source type. Consequently, you would
not consider technologies in the pilot scale testing stages of
development as ``available'' for purposes of BART review.
3. Commercial availability by itself, however, is not
necessarily a sufficient basis for concluding a technology to be
applicable and therefore technically feasible. Technical
feasibility, as determined in Step 2, also means a control option
may reasonably be deployed on or ``applicable'' to the source type
under consideration.
Because a new technology may become available at various points
in time during the BART analysis process, we believe that guidelines
are needed on when a technology must be considered. For example, a
technology may become available during the public comment period on
the State's rule development process. Likewise, it is possible that
new technologies may become available after the close of the State's
public comment period and before submittal of the SIP to EPA, or
during EPA's review process on the SIP submittal. In order to
provide certainty in the process, all technologies should be
considered if available before the close of the State's public
comment period. You need not consider technologies that become
available after this date. As part of your analysis, you should
consider any technologies brought to your attention in public
comments. If you disagree with public comments asserting that the
technology is available, you should provide an explanation for the
public record as to the basis for your conclusion.
What do we mean by ``applicable'' technology?
You need to exercise technical judgment in determining whether a
control alternative is applicable to the source type under
consideration. In general, a commercially available control option
will be presumed applicable if it has been used on the same or a
similar source type. Absent a showing of this type, you evaluate
technical feasibility by examining the physical and chemical
characteristics of the pollutant-bearing gas stream, and comparing
them to the gas stream characteristics of the source types to which
the technology had been applied previously. Deployment of the
control technology on a new or existing source with similar gas
stream characteristics is generally a sufficient basis for
concluding the technology is technically feasible barring a
demonstration to the contrary as described below.
What type of demonstration is required if I conclude that an option is
not technically feasible?
1. Where you conclude that a control option identified in Step 1
is technically infeasible, you should demonstrate that the option is
either commercially unavailable, or that specific circumstances
preclude its application to a particular emission unit. Generally,
such a demonstration involves an evaluation of the characteristics
of the pollutant-bearing gas stream and the capabilities of the
technology. Alternatively, a demonstration of technical
infeasibility may involve a showing that there are unresolvable
technical difficulties with applying the control to the source
(e.g., size of the unit, location of the proposed site, operating
problems related to specific circumstances of the source, space
constraints, reliability, and adverse side effects on the rest of
the facility). Where the resolution of technical difficulties is
merely a matter of increased cost, you should consider the
technology to be technically feasible. The cost of a control
alternative is considered later in the process.
2. The determination of technical feasibility is sometimes
influenced by recent air quality permits. In some cases, an air
quality permit may require a certain level of control, but the level
of control in a permit is not expected to be achieved in practice
(e.g., a source has received a permit but the project was canceled,
or every operating source at that permitted level has been
physically unable to achieve compliance with the limit). Where this
is the case, you should provide supporting documentation showing why
such limits are not technically feasible, and, therefore, why the
level of control (but not necessarily the technology) may be
eliminated from further consideration. However, if there is a permit
requiring the application of a certain technology or emission limit
to be achieved for such technology, this usually is sufficient
justification for you to assume the technical feasibility of that
technology or emission limit.
3. Physical modifications needed to resolve technical obstacles
do not, in and of themselves, provide a justification for
eliminating the control technique on the basis of technical
infeasibility. However, you may consider the cost of such
modifications in estimating costs. This, in turn, may form the basis
for eliminating a control technology (see later discussion).
4. Vendor guarantees may provide an indication of commercial
availability and the technical feasibility of a control technique
and could contribute to a determination of technical feasibility or
technical infeasibility, depending on circumstances. However, we do
not consider a vendor guarantee alone to be sufficient justification
that a control option will work. Conversely, lack of a vendor
guarantee by itself does not present sufficient justification that a
control option or an emissions limit is technically infeasible.
Generally, you should make decisions about technical feasibility
based on chemical, and engineering analyses (as discussed above), in
conjunction with information about vendor guarantees.
5. A possible outcome of the BART procedures discussed in these
guidelines is the evaluation of multiple control technology
alternatives which result in essentially equivalent emissions. It is
not our intent to encourage evaluation of unnecessarily large
numbers of control alternatives for every emissions unit.
Consequently, you should use judgment in deciding on those
alternatives for which you will conduct the detailed impacts
analysis (Step 4 below). For example, if two or more control
techniques result in control levels that are essentially identical,
considering the uncertainties of emissions factors and other
parameters
[[Page 39166]]
pertinent to estimating performance, you may evaluate only the less
costly of these options. You should narrow the scope of the BART
analysis in this way only if there is a negligible difference in
emissions and energy and non-air quality environmental impacts
between control alternatives.
3. STEP 3: How do I evaluate technically feasible alternatives?
Step 3 involves evaluating the control effectiveness of all the
technically feasible control alternatives identified in Step 2 for
the pollutant and emissions unit under review.
Two key issues in this process include:
(1) Making sure that you express the degree of control using a
metric that ensures an ``apples to apples'' comparison of emissions
performance levels among options, and
(2) Giving appropriate treatment and consideration of control
techniques that can operate over a wide range of emission
performance levels.
What are the appropriate metrics for comparison?
This issue is especially important when you compare inherently
lower-polluting processes to one another or to add-on controls. In
such cases, it is generally most effective to express emissions
performance as an average steady state emissions level per unit of
product produced or processed.
Examples of common metrics:
Pounds of SO2 emissions per million Btu heat
input, and
Pounds of NOX emissions per ton of cement
produced.
How do I evaluate control techniques with a wide range of emission
performance levels?
1. Many control techniques, including both add-on controls and
inherently lower polluting processes, can perform at a wide range of
levels. Scrubbers and high and low efficiency electrostatic
precipitators (ESPs) are two of the many examples of such control
techniques that can perform at a wide range of levels. It is not our
intent to require analysis of each possible level of efficiency for
a control technique as such an analysis would result in a large
number of options. It is important, however, that in analyzing the
technology you take into account the most stringent emission control
level that the technology is capable of achieving. You should
consider recent regulatory decisions and performance data (e.g.,
manufacturer's data, engineering estimates and the experience of
other sources) when identifying an emissions performance level or
levels to evaluate.
2. In assessing the capability of the control alternative,
latitude exists to consider special circumstances pertinent to the
specific source under review, or regarding the prior application of
the control alternative. However, you should explain the basis for
choosing the alternate level (or range) of control in the BART
analysis. Without a showing of differences between the source and
other sources that have achieved more stringent emissions limits,
you should conclude that the level being achieved by those other
sources is representative of the achievable level for the source
being analyzed.
3. You may encounter cases where you may wish to evaluate other
levels of control in addition to the most stringent level for a
given device. While you must consider the most stringent level as
one of the control options, you may consider less stringent levels
of control as additional options. This would be useful, particularly
in cases where the selection of additional options would have widely
varying costs and other impacts.
4. Finally, we note that for retrofitting existing sources in
addressing BART, you should consider ways to improve the performance
of existing control devices, particularly when a control device is
not achieving the level of control that other similar sources are
achieving in practice with the same device. For example, you should
consider requiring those sources with electrostatic precipitators
(ESPs) performing below currently achievable levels to improve their
performance.
4. STEP 4: For a BART review, what impacts am I expected to calculate
and report? What methods does EPA recommend for the impacts analysis?
After you identify the available and technically feasible
control technology options, you are expected to conduct the
following analyses when you make a BART determination:
Impact analysis part 1: Costs of compliance,
Impact analysis part 2: Energy impacts, and
Impact analysis part 3: Non-air quality environmental impacts.
Impact analysis part 4: Remaining useful life.
In this section, we describe how to conduct each of these three
analyses. You are responsible for presenting an evaluation of each
impact along with appropriate supporting information. You should
discuss and, where possible, quantify both beneficial and adverse
impacts. In general, the analysis should focus on the direct impact
of the control alternative.
a. Impact analysis part 1: how do I estimate the costs of control?
1. To conduct a cost analysis, you:
(1) Identify the emissions units being controlled,
(2) Identify design parameters for emission controls, and
(3) Develop cost estimates based upon those design parameters.
2. It is important to identify clearly the emission units being
controlled, that is, to specify a well-defined area or process
segment within the plant. In some cases, multiple emission units can
be controlled jointly. However, in other cases, it may be
appropriate in the cost analysis to consider whether multiple units
will be required to install separate and/or different control
devices. The analysis should provide a clear summary list of
equipment and the associated control costs. Inadequate documentation
of the equipment whose emissions are being controlled is a potential
cause for confusion in comparison of costs of the same controls
applied to similar sources.
3. You then specify the control system design parameters.
Potential sources of these design parameters include equipment
vendors, background information documents used to support NSPS
development, control technique guidelines documents, cost manuals
developed by EPA, control data in trade publications, and
engineering and performance test data. The following are a few
examples of design parameters for two example control measures:
------------------------------------------------------------------------
Control device Examples of design parameters
------------------------------------------------------------------------
Wet Scrubbers......................... Type of sorbent used (lime,
limestone, etc.).
Gas pressure drop.
Liquid/gas ratio.
Selective Catalytic Reduction......... Ammonia to NOX molar ratio.
Pressure drop.
Catalyst life.
------------------------------------------------------------------------
4. The value selected for the design parameter should ensure
that the control option will achieve the level of emission control
being evaluated. You should include in your analysis documentation
of your assumptions regarding design parameters. Examples of
supporting references would include the EPA OAQPS Control Cost
Manual (see below) and background information documents used for
NSPS and hazardous pollutant emission standards. If the design
parameters you specified differ from typical designs, you should
document the difference by supplying performance test data for the
control technology in question applied to the same source or a
similar source.
5. Once the control technology alternatives and achievable
emissions performance levels have been identified, you then develop
estimates of capital and annual costs. The basis for equipment cost
estimates also should be documented, either with data supplied by an
equipment vendor (i.e., budget estimates or bids) or by a referenced
source (such as the OAQPS Control Cost Manual, Fifth Edition,
February 1996, EPA 453/B-96-001).\14\ In order to maintain and
improve consistency, cost estimates should be based on the OAQPS
Control Cost Manual, where possible.\15\ The Control Cost Manual
addresses most control technologies in sufficient detail for a BART
analysis. The cost analysis should also take into account any site-
specific design or other conditions identified above that affect the
cost of a particular BART technology option.
---------------------------------------------------------------------------
\14\ The OAQPS Control Cost Manual is updated periodically.
While this citation refers to the latest version at the time this
guidance was written, you should use the version that is current as
of when you conduct your impact analysis. This document is available
at the following Web site: http://www.epa.gov/ttn/catc/dir1/cs1ch2.pdf.
\15\ You should include documentation for any additional
information you used for the cost calculations, including any
information supplied by vendors that affects your assumptions
regarding purchased equipment costs, equipment life, replacement of
major components, and any other element of the calculation that
differs from the Control Cost Manual.
---------------------------------------------------------------------------
[[Page 39167]]
b. What do we mean by cost effectiveness?
Cost effectiveness, in general, is a criterion used to assess
the potential for achieving an objective in the most economical way.
For purposes of air pollutant analysis, ``effectiveness'' is
measured in terms of tons of pollutant emissions removed, and
``cost'' is measured in terms of annualized control costs. We
recommend two types of cost-effectiveness calculations--average cost
effectiveness, and incremental cost effectiveness.
c. How do I calculate average cost effectiveness?
Average cost effectiveness means the total annualized costs of
control divided by annual emissions reductions (the difference
between baseline annual emissions and the estimate of emissions
after controls), using the following formula:
Average cost effectiveness (dollars per ton removed) = Control
option annualized cost \16\
---------------------------------------------------------------------------
\16\ Whenever you calculate or report annual costs, you should
indicate the year for which the costs are estimated. For example, if
you use the year 2000 as the basis for cost comparisons, you would
report that an annualized cost of $20 million would be: $20 million
(year 2000 dollars).
Baseline annual emissions--Annual emissions with Control option
Because you calculate costs in (annualized) dollars per year ($/
yr) and because you calculate emissions rates in tons per year
(tons/yr), the result is an average cost-effectiveness number in
(annualized) dollars per ton ($/ton) of pollutant removed.
d. How do I calculate baseline emissions?
1. The baseline emissions rate should represent a realistic
depiction of anticipated annual emissions for the source. In
general, for the existing sources subject to BART, you will estimate
the anticipated annual emissions based upon actual emissions from a
baseline period.
2. When you project that future operating parameters (e.g.,
limited hours of operation or capacity utilization, type of fuel,
raw materials or product mix or type) will differ from past
practice, and if this projection has a deciding effect in the BART
determination, then you must make these parameters or assumptions
into enforceable limitations. In the absence of enforceable
limitations, you calculate baseline emissions based upon
continuation of past practice.
3. For example, the baseline emissions calculation for an
emergency standby generator may consider the fact that the source
owner would not operate more than past practice of 2 weeks a year.
On the other hand, baseline emissions associated with a base-loaded
turbine should be based on its past practice which would indicate a
large number of hours of operation. This produces a significantly
higher level of baseline emissions than in the case of the
emergency/standby unit and results in more cost-effective controls.
As a consequence of the dissimilar baseline emissions, BART for the
two cases could be very different.
e. How do I calculate incremental cost effectiveness?
1. In addition to the average cost effectiveness of a control
option, you should also calculate incremental cost effectiveness.
You should consider the incremental cost effectiveness in
combination with the average cost effectiveness when considering
whether to eliminate a control option. The incremental cost
effectiveness calculation compares the costs and performance level
of a control option to those of the next most stringent option, as
shown in the following formula (with respect to cost per emissions
reduction):
Incremental Cost Effectiveness (dollars per incremental ton removed)
= (Total annualized costs of control option) - (Total annualized
costs of next control option) / (Control option annual emissions) -
(Next control option annual emissions)
Example 1: Assume that Option F on Figure 2 has total
annualized costs of $1 million to reduce 2000 tons of a pollutant,
and that Option D on Figure 2 has total annualized costs of $500,000
to reduce 1000 tons of the same pollutant. The incremental cost
effectiveness of Option F relative to Option D is ($1 million -
$500,000) divided by (2000 tons - 1000 tons), or $500,000 divided by
1000 tons, which is $500/ton.
Example 2: Assume that two control options exist: Option 1 and
Option 2. Option 1 achieves a 1,000 ton/yr reduction at an
annualized cost of $1,900,000. This represents an average cost of
($1,900,000/1,000 tons) = $1,900/ton. Option 2 achieves a 980 tons/
yr reduction at an annualized cost of $1,500,000. This represents an
average cost of ($1,500,000/980 tons) = $1,531/ton. The incremental
cost effectiveness of Option 1 relative to Option 2 is ($1,900,000 -
$1,500,000) divided by (1,000 tons - 980 tons). The adoption of
Option 1 instead of Option 2 results in an incremental emission
reduction of 20 tons per year at an additional cost of $400,000 per
year. The incremental cost of Option 1, then, is $20,000 per ton -
11 times the average cost of $1,900 per ton. While $1,900 per ton
may still be deemed reasonable, it is useful to consider both the
average and incremental cost in making an overall cost-effectiveness
finding. Of course, there may be other differences between these
options, such as, energy or water use, or non-air environmental
effects, which also should be considered in selecting a BART
technology.
2. You should exercise care in deriving incremental costs of
candidate control options. Incremental cost-effectiveness
comparisons should focus on annualized cost and emission reduction
differences between ``dominant'' alternatives. To identify dominant
alternatives, you generate a graphical plot of total annualized
costs for total emissions reductions for all control alternatives
identified in the BART analysis, and by identifying a ``least-cost
envelope'' as shown in Figure 2. (A ``least-cost envelope''
represents the set of options that should be dominant in the choice
of a specific option.)
[[Page 39168]]
[GRAPHIC] [TIFF OMITTED] TR06JY05.000
Example: Eight technically feasible control options for
analysis are listed. These are represented as A through H in Figure
2. The dominant set of control options, B, D, F, G, and H, represent
the least-cost envelope, as we depict by the cost curve connecting
them. Points A, C and E are inferior options, and you should not use
them in calculating incremental cost effectiveness. Points A, C and
E represent inferior controls because B will buy more emissions
reductions for less money than A; and similarly, D and F will buy
more reductions for less money than C and E, respectively.
3. In calculating incremental costs, you:
(1) Array the control options in ascending order of annualized
total costs,
(2) Develop a graph of the most reasonable smooth curve of the
control options, as shown in Figure 2. This is to show the ``least-
cost envelope'' discussed above; and
(3) Calculate the incremental cost effectiveness for each
dominant option, which is the difference in total annual costs
between that option and the next most stringent option, divided by
the difference in emissions, after controls have been applied,
between those two control options. For example, using Figure 2, you
would calculate incremental cost effectiveness for the difference
between options B and D, options D and F, options F and G, and
options G and H.
4. A comparison of incremental costs can also be useful in
evaluating the viability of a specific control option over a range
of efficiencies. For example, depending on the capital and
operational cost of a control device, total and incremental cost may
vary significantly (either increasing or decreasing) over the
operational range of a control device. Also, the greater the number
of possible control options that exist, the more weight should be
given to the incremental costs vs. average costs. It should be noted
that average and incremental cost effectiveness are identical when
only one candidate control option is known to exist.
5. You should exercise caution not to misuse these techniques.
For example, you may be faced with a choice between two available
control devices at a source, control A and control B, where control
B achieves slightly greater emission reductions. The average cost
(total annual cost/total annual emission reductions) for each may be
deemed to be reasonable. However, the incremental cost (total annual
costA - B/total annual emission
reductionsA - B) of the additional emission reductions to
be achieved by control B may be very great. In such an instance, it
may be inappropriate to choose control B, based on its high
incremental costs, even though its average cost may be considered
reasonable.
6. In addition, when you evaluate the average or incremental
cost effectiveness of a control alternative, you should make
reasonable and supportable assumptions regarding control
efficiencies. An unrealistically low assessment of the emission
reduction potential of a certain technology could result in inflated
cost-effectiveness figures.
f. What other information should I provide in the cost impacts
analysis?
You should provide documentation of any unusual circumstances
that exist for the source that would lead to cost-effectiveness
estimates that would exceed that for recent retrofits. This is
especially important in cases where recent retrofits have cost-
effectiveness values that are within what has been considered a
reasonable range, but your analysis concludes that costs for the
source being analyzed are not considered reasonable. (A reasonable
range would be a range that is consistent with the range of cost
effectiveness values used in other similar permit decisions over a
period of time.)
Example: In an arid region, large amounts of water are needed
for a scrubbing system. Acquiring water from a distant location
could greatly increase the cost per ton of emissions reduced of wet
scrubbing as a control option.
g. What other things are important to consider in the cost impacts
analysis?
In the cost analysis, you should take care not to focus on
incomplete results or partial calculations. For example, large
capital costs for a control option alone would not preclude
selection of a control measure if large emissions reductions are
projected. In such a case, low or reasonable cost effectiveness
numbers may validate the option as an appropriate BART alternative
irrespective of the large capital costs. Similarly, projects with
relatively low capital costs may not be cost effective if there are
few emissions reduced.
h. Impact analysis part 2: How should I analyze and report energy
impacts?
1. You should examine the energy requirements of the control
technology and determine whether the use of that technology results
in energy penalties or benefits. A source owner may, for example,
benefit from the combustion of a concentrated gas stream rich in
volatile organic compounds; on the other hand, more often extra fuel
or electricity is required to power a control
[[Page 39169]]
device or incinerate a dilute gas stream. If such benefits or
penalties exist, they should be quantified to the extent
practicable. Because energy penalties or benefits can usually be
quantified in terms of additional cost or income to the source, the
energy impacts analysis can, in most cases, simply be factored into
the cost impacts analysis. The fact of energy use in and of itself
does not disqualify a technology.
2. Your energy impact analysis should consider only direct
energy consumption and not indirect energy impacts. For example, you
could estimate the direct energy impacts of the control alternative
in units of energy consumption at the source (e.g., BTU, kWh,
barrels of oil, tons of coal). The energy requirements of the
control options should be shown in terms of total (and in certain
cases, also incremental) energy costs per ton of pollutant removed.
You can then convert these units into dollar costs and, where
appropriate, factor these costs into the control cost analysis.
3. You generally do not consider indirect energy impacts (such
as energy to produce raw materials for construction of control
equipment). However, if you determine, either independently or based
on a showing by the source owner, that the indirect energy impact is
unusual or significant and that the impact can be well quantified,
you may consider the indirect impact.
4. The energy impact analysis may also address concerns over the
use of locally scarce fuels. The designation of a scarce fuel may
vary from region to region. However, in general, a scarce fuel is
one which is in short supply locally and can be better used for
alternative purposes, or one which may not be reasonably available
to the source either at the present time or in the near future.
5. Finally, the energy impacts analysis may consider whether
there are relative differences between alternatives regarding the
use of locally or regionally available coal, and whether a given
alternative would result in significant economic disruption or
unemployment. For example, where two options are equally cost
effective and achieve equivalent or similar emissions reductions,
one option may be preferred if the other alternative results in
significant disruption or unemployment.
i. Impact analysis part 3: How do I analyze ``non-air quality
environmental impacts?''
1. In the non-air quality related environmental impacts portion
of the BART analysis, you address environmental impacts other than
air quality due to emissions of the pollutant in question. Such
environmental impacts include solid or hazardous waste generation
and discharges of polluted water from a control device.
2. You should identify any significant or unusual environmental
impacts associated with a control alternative that have the
potential to affect the selection or elimination of a control
alternative. Some control technologies may have potentially
significant secondary environmental impacts. Scrubber effluent, for
example, may affect water quality and land use. Alternatively, water
availability may affect the feasibility and costs of wet scrubbers.
Other examples of secondary environmental impacts could include
hazardous waste discharges, such as spent catalysts or contaminated
carbon. Generally, these types of environmental concerns become
important when sensitive site-specific receptors exist or when the
incremental emissions reductions potential of the more stringent
control is only marginally greater than the next most-effective
option. However, the fact that a control device creates liquid and
solid waste that must be disposed of does not necessarily argue
against selection of that technology as BART, particularly if the
control device has been applied to similar facilities elsewhere and
the solid or liquid waste is similar to those other applications. On
the other hand, where you or the source owner can show that unusual
circumstances at the proposed facility create greater problems than
experienced elsewhere, this may provide a basis for the elimination
of that control alternative as BART.
3. The procedure for conducting an analysis of non-air quality
environmental impacts should be made based on a consideration of
site-specific circumstances. If you propose to adopt the most
stringent alternative, then it is not necessary to perform this
analysis of environmental impacts for the entire list of
technologies you ranked in Step 3. In general, the analysis need
only address those control alternatives with any significant or
unusual environmental impacts that have the potential to affect the
selection of a control alternative, or elimination of a more
stringent control alternative. Thus, any important relative
environmental impacts (both positive and negative) of alternatives
can be compared with each other.
4. In general, the analysis of impacts starts with the
identification and quantification of the solid, liquid, and gaseous
discharges from the control device or devices under review.
Initially, you should perform a qualitative or semi-quantitative
screening to narrow the analysis to discharges with potential for
causing adverse environmental effects. Next, you should assess the
mass and composition of any such discharges and quantify them to the
extent possible, based on readily available information. You should
also assemble pertinent information about the public or
environmental consequences of releasing these materials.
j. Impact analysis part 4: What are examples of non-air quality
environmental impacts?
The following are examples of how to conduct non-air quality
environmental impacts:
(1) Water Impact
You should identify the relative quantities of water used and
water pollutants produced and discharged as a result of the use of
each alternative emission control system. Where possible, you should
assess the effect on ground water and such local surface water
quality parameters as ph, turbidity, dissolved oxygen, salinity,
toxic chemical levels, temperature, and any other important
considerations. The analysis could consider whether applicable water
quality standards will be met and the availability and effectiveness
of various techniques to reduce potential adverse effects.
(2) Solid Waste Disposal Impact
You could also compare the quality and quantity of solid waste
(e.g., sludges, solids) that must be stored and disposed of or
recycled as a result of the application of each alternative emission
control system. You should consider the composition and various
other characteristics of the solid waste (such as permeability,
water retention, rewatering of dried material, compression strength,
leachability of dissolved ions, bulk density, ability to support
vegetation growth and hazardous characteristics) which are
significant with regard to potential surface water pollution or
transport into and contamination of subsurface waters or aquifers.
(3) Irreversible or Irretrievable Commitment of Resources
You may consider the extent to which the alternative emission
control systems may involve a trade-off between short-term
environmental gains at the expense of long-term environmental losses
and the extent to which the alternative systems may result in
irreversible or irretrievable commitment of resources (for example,
use of scarce water resources).
(4) Other Adverse Environmental Impacts
You may consider significant differences in noise levels,
radiant heat, or dissipated static electrical energy of pollution
control alternatives. Other examples of non-air quality
environmental impacts would include hazardous waste discharges such
as spent catalysts or contaminated carbon.
k. How do I take into account a project's ``remaining useful life'' in
calculating control costs?
1. You may decide to treat the requirement to consider the
source's ``remaining useful life'' of the source for BART
determinations as one element of the overall cost analysis. The
``remaining useful life'' of a source, if it represents a relatively
short time period, may affect the annualized costs of retrofit
controls. For example, the methods for calculating annualized costs
in EPA's OAQPS Control Cost Manual require the use of a specified
time period for amortization that varies based upon the type of
control. If the remaining useful life will clearly exceed this time
period, the remaining useful life has essentially no effect on
control costs and on the BART determination process. Where the
remaining useful life is less than the time period for amortizing
costs, you should use this shorter time period in your cost
calculations.
2. For purposes of these guidelines, the remaining useful life
is the difference between:
(1) The date that controls will be put in place (capital and
other construction costs incurred before controls are put in place
can be rolled into the first year, as suggested in EPA's OAQPS
Control Cost Manual); you are conducting the BART analysis; and
(2) The date the facility permanently stops operations. Where
this affects the BART determination, this date should be assured by
a federally- or State-enforceable restriction preventing further
operation.
3. We recognize that there may be situations where a source
operator intends to shut down a source by a given date, but wishes
to retain the flexibility to continue
[[Page 39170]]
operating beyond that date in the event, for example, that market
conditions change. Where this is the case, your BART analysis may
account for this, but it must maintain consistency with the
statutory requirement to install BART within 5 years. Where the
source chooses not to accept a federally enforceable condition
requiring the source to shut down by a given date, it is necessary
to determine whether a reduced time period for the remaining useful
life changes the level of controls that would have been required as
BART.
If the reduced time period does change the level of BART
controls, you may identify, and include as part of the BART emission
limitation, the more stringent level of control that would be
required as BART if there were no assumption that reduced the
remaining useful life. You may incorporate into the BART emission
limit this more stringent level, which would serve as a contingency
should the source continue operating more than 5 years after the
date EPA approves the relevant SIP. The source would not be allowed
to operate after the 5-year mark without such controls. If a source
does operate after the 5-year mark without BART in place, the source
is considered to be in violation of the BART emissions limit for
each day of operation.
5. Step 5: How should I determine visibility impacts in the BART
determination?
The following is an approach you may use to determine visibility
impacts (the degree of visibility improvement for each source
subject to BART) for the BART determination. Once you have
determined that your source or sources are subject to BART, you must
conduct a visibility improvement determination for the source(s) as
part of the BART determination. When making this determination, we
believe you have flexibility in setting absolute thresholds, target
levels of improvement, or de minimis levels since the deciview
improvement must be weighed among the five factors, and you are free
to determine the weight and significance to be assigned to each
factor. For example, a 0.3 deciview improvement may merit a stronger
weighting in one case versus another, so one ``bright line'' may not
be appropriate. [Note that if sources have elected to apply the most
stringent controls available, consistent with the discussion in
section E. step 1. below, you need not conduct, or require the
source to conduct, an air quality modeling analysis for the purpose
of determining its visibility impacts.]
Use CALPUFF,\17\ or other appropriate dispersion model to
determine the visibility improvement expected at a Class I area from
the potential BART control technology applied to the source.
Modeling should be conducted for SO2, NOX, and
direct PM emissions (PM2.5 and/or PM10). If
the source is making the visibility determination, you should review
and approve or disapprove of the source's analysis before making the
expected improvement determination. There are several steps for
determining the visibility impacts from an individual source using a
dispersion model:
---------------------------------------------------------------------------
\17\ The model code and its documentation are available at no
cost for download from http://www.epa.gov/scram001/tt22.htm#calpuff.
---------------------------------------------------------------------------
Develop a modeling protocol.
Some critical items to include in a modeling protocol are
meteorological and terrain data, as well as source-specific
information (stack height, temperature, exit velocity, elevation,
and allowable and actual emission rates of applicable pollutants),
and receptor data from appropriate Class I areas. We recommend
following EPA's Interagency Workgroup on Air Quality Modeling
(IWAQM) Phase 2 Summary Report and Recommendations for Modeling Long
Range Transport Impacts \18\ for parameter settings and
meteorological data inputs; the use of other settings from those in
IWAQM should be identified and explained in the protocol.
---------------------------------------------------------------------------
\18\ Interagency Workgroup on Air Quality Modeling (IWAQM) Phase
2 Summary Report and Recommendations for Modeling Long Range
Transport Impacts, U.S. Environmental Protection Agency, EPA-454/R-
98-019, December 1998.
---------------------------------------------------------------------------
One important element of the protocol is in establishing the
receptors that will be used in the model. The receptors that you use
should be located in the nearest Class I area with sufficient
density to identify the likely visibility effects of the source. For
other Class I areas in relatively close proximity to a BART-eligible
source, you may model a few strategic receptors to determine whether
effects at those areas may be greater than at the nearest Class I
area. For example, you might chose to locate receptors at these
areas at the closest point to the source, at the highest and lowest
elevation in the Class I area, at the IMPROVE monitor, and at the
approximate expected plume release height. If the highest modeled
effects are observed at the nearest Class I area, you may choose not
to analyze the other Class I areas any further as additional
analyses might be unwarranted.
You should bear in mind that some receptors within the relevant
Class I area may be less than 50 km from the source while other
receptors within that same Class I area may be greater than 50 km
from the same source. As indicated by the Guideline on Air Quality
Models, this situation may call for the use of two different
modeling approaches for the same Class I area and source, depending
upon the State's chosen method for modeling sources less than 50 km.
In situations where you are assessing visibility impacts for source-
receptor distances less than 50 km, you should use expert modeling
judgment in determining visibility impacts, giving consideration to
both CALPUFF and other EPA-approved methods.
In developing your modeling protocol, you may want to consult
with EPA and your regional planning organization (RPO). Up-front
consultation will ensure that key technical issues are addressed
before you conduct your modeling.
For each source, run the model, at pre-control and
post-control emission rates according to the accepted methodology in
the protocol.
Use the 24-hour average actual emission rate from the highest
emitting day of the meteorological period modeled (for the pre-
control scenario). Calculate the model results for each receptor as
the change in deciviews compared against natural visibility
conditions. Post-control emission rates are calculated as a
percentage of pre-control emission rates. For example, if the 24-hr
pre-control emission rate is 100 lb/hr of SO2, then the
post control rate is 5 lb/hr if the control efficiency being
evaluated is 95 percent.
Make the net visibility improvement determination.
Assess the visibility improvement based on the modeled change in
visibility impacts for the pre-control and post-control emission
scenarios. You have flexibility to assess visibility improvements
due to BART controls by one or more methods. You may consider the
frequency, magnitude, and duration components of impairment.
Suggestions for making the determination are:
Use of a comparison threshold, as is done for
determining if BART-eligible sources should be subject to a BART
determination. Comparison thresholds can be used in a number of ways
in evaluating visibility improvement (e.g. the number of days or
hours that the threshold was exceeded, a single threshold for
determining whether a change in impacts is significant, or a
threshold representing an x percent change in improvement).
Compare the 98th percent days for the pre- and post-
control runs.
Note that each of the modeling options may be supplemented with
source apportionment data or source apportionment modeling.
E. How do I select the ``best'' alternative, using the results of
Steps 1 through 5?
1. Summary of the Impacts Analysis
From the alternatives you evaluated in Step 3, we recommend you
develop a chart (or charts) displaying for each of the alternatives:
(1) Expected emission rate (tons per year, pounds per hour);
(2) Emissions performance level (e.g., percent pollutant
removed, emissions per unit product, lb/MMBtu, ppm);
(3) Expected emissions reductions (tons per year);
(4) Costs of compliance--total annualized costs ($), cost
effectiveness ($/ton), and incremental cost effectiveness ($/ton),
and/or any other cost-effectiveness measures (such as $/deciview);
(5) Energy impacts;
(6) Non-air quality environmental impacts; and
(7) Modeled visibility impacts.
2. Selecting a ``best'' alternative
1. You have discretion to determine the order in which you
should evaluate control options for BART. Whatever the order in
which you choose to evaluate options, you should always (1) display
the options evaluated; (2) identify the average and incremental
costs of each option; (3) consider the energy and non-air quality
environmental impacts of each option; (4) consider the remaining
useful life; and (5) consider the modeled visibility impacts. You
should provide a justification for adopting the technology that you
select as the ``best'' level of control, including an explanation of
the
[[Page 39171]]
CAA factors that led you to choose that option over other control
levels.
2. In the case where you are conducting a BART determination for
two regulated pollutants on the same source, if the result is two
different BART technologies that do not work well together, you
could then substitute a different technology or combination of
technologies.
3. In selecting a ``best'' alternative, should I consider the
affordability of controls?
1. Even if the control technology is cost effective, there may
be cases where the installation of controls would affect the
viability of continued plant operations.
2. There may be unusual circumstances that justify taking into
consideration the conditions of the plant and the economic effects
of requiring the use of a given control technology. These effects
would include effects on product prices, the market share, and
profitability of the source. Where there are such unusual
circumstances that are judged to affect plant operations, you may
take into consideration the conditions of the plant and the economic
effects of requiring the use of a control technology. Where these
effects are judged to have a severe impact on plant operations you
may consider them in the selection process, but you may wish to
provide an economic analysis that demonstrates, in sufficient detail
for public review, the specific economic effects, parameters, and
reasoning. (We recognize that this review process must preserve the
confidentiality of sensitive business information). Any analysis may
also consider whether other competing plants in the same industry
have been required to install BART controls if this information is
available.
4. Sulfur dioxide limits for utility boilers
You must require 750 MW power plants to meet specific control
levels for SO2 of either 95 percent control or 0.15 lbs/
MMBtu, for each EGU greater than 200 MW that is currently
uncontrolled unless you determine that an alternative control level
is justified based on a careful consideration of the statutory
factors. Thus, for example, if the source demonstrates circumstances
affecting its ability to cost-effectively reduce its emissions, you
should take that into account in determining whether the presumptive
levels of control are appropriate for that facility. For a currently
uncontrolled EGU greater than 200 MW in size, but located at a power
plant smaller than 750 MW in size, such controls are generally cost-
effective and could be used in your BART determination considering
the five factors specified in CAA section 169A(g)(2). While these
levels may represent current control capabilities, we expect that
scrubber technology will continue to improve and control costs
continue to decline. You should be sure to consider the level of
control that is currently best achievable at the time that you are
conducting your BART analysis.
For coal-fired EGUs with existing post-combustion SO2
controls achieving less than 50 percent removal efficiencies, we
recommend that you evaluate constructing a new FGD system to meet
the same emission limits as above (95 percent removal or 0.15 lb/
mmBtu), in addition to the evaluation of scrubber upgrades discussed
below. For oil-fired units, regardless of size, you should evaluate
limiting the sulfur content of the fuel oil burned to 1 percent or
less by weight.
For those BART-eligible EGUs with pre-existing post-combustion
SO2 controls achieving removal efficiencies of at least
50 percent, your BART determination should consider cost effective
scrubber upgrades designed to improve the system's overall
SO2 removal efficiency. There are numerous scrubber
enhancements available to upgrade the average removal efficiencies
of all types of existing scrubber systems. We recommend that as you
evaluate the definition of ``upgrade,'' you evaluate options that
not only improve the design removal efficiency of the scrubber
vessel itself, but also consider upgrades that can improve the
overall SO2 removal efficiency of the scrubber system.
Increasing a scrubber system's reliability, and conversely
decreasing its downtime, by way of optimizing operation procedures,
improving maintenance practices, adjusting scrubber chemistry, and
increasing auxiliary equipment redundancy, are all ways to improve
average SO2 removal efficiencies.
We recommend that as you evaluate the performance of existing
wet scrubber systems, you consider some of the following upgrades,
in no particular order, as potential scrubber upgrades that have
been proven in the industry as cost effective means to increase
overall SO2 removal of wet systems:
(a) Elimination of Bypass Reheat;
(b) Installation of Liquid Distribution Rings;
(c) Installation of Perforated Trays;
(d) Use of Organic Acid Additives;
(e) Improve or Upgrade Scrubber Auxiliary System Equipment;
(f) Redesign Spray Header or Nozzle Configuration.
We recommend that as you evaluate upgrade options for dry
scrubber systems, you should consider the following cost effective
upgrades, in no particular order:
(a) Use of Performance Additives;
(b) Use of more Reactive Sorbent;
(c) Increase the Pulverization Level of Sorbent;
(d) Engineering redesign of atomizer or slurry injection system.
You should evaluate scrubber upgrade options based on the 5 step
BART analysis process.
5. Nitrogen oxide limits for utility boilers
You should establish specific numerical limits for
NOX control for each BART determination. For power plants
with a generating capacity in excess of 750 MW currently using
selective catalytic reduction (SCR) or selective non-catalytic
reduction (SNCR) for part of the year, you should presume that use
of those same controls year-round is BART. For other sources
currently using SCR or SNCR to reduce NOX emissions
during part of the year, you should carefully consider requiring the
use of these controls year-round as the additional costs of
operating the equipment throughout the year would be relatively
modest.
For coal-fired EGUs greater than 200 MW located at greater than
750 MW power plants and operating without post-combustion controls
(i.e. SCR or SNCR), we have provided presumptive NOX
limits, differentiated by boiler design and type of coal burned. You
may determine that an alternative control level is appropriate based
on a careful consideration of the statutory factors. For coal-fired
EGUs greater than 200 MW located at power plants 750 MW or less in
size and operating without post-combustion controls, you should
likewise presume that these same levels are cost-effective. You
should require such utility boilers to meet the following
NOX emission limits, unless you determine that an
alternative control level is justified based on consideration of the
statutory factors. The following NOX emission rates were
determined based on a number of assumptions, including that the EGU
boiler has enough volume to allow for installation and effective
operation of separated overfire air ports. For boilers where these
assumptions are incorrect, these emission limits may not be cost-
effective.
[[Page 39172]]
Table 1.--Presumptive NOX Emission Limits for BART-Eligible Coal-Fired
Units.\19\
------------------------------------------------------------------------
NOX presumptive
Unit type Coal type limit (lb/
mmbtu) \20\
------------------------------------------------------------------------
Dry-bottom wall-fired......... Bituminous............ 0.39
Sub-bituminous........ 0.23
Lignite............... 0.29
Tangential-fired.............. Bituminous............ 0.28
Sub-bituminous........ 0.15
Lignite............... 0.17
Cell Burners.................. Bituminous............ 0.40
Sub-bituminous........ 0.45
Dry-turbo-fired............... Bituminous............ 0.32
Sub-bituminous........ 0.23
Wet-bottom tangential-fired... Bituminous............ 0.62
------------------------------------------------------------------------
Most EGUs can meet these presumptive NOX limits
through the use of current combustion control technology, i.e. the
careful control of combustion air and low-NOX burners.
For units that cannot meet these limits using such technologies, you
should consider whether advanced combustion control technologies
such as rotating opposed fire air should be used to meet these
limits.
---------------------------------------------------------------------------
\19\ No Cell burners, dry-turbo-fired units, nor wet-bottom
tangential-fired units burning lignite were identified as BART-
eligible, thus no presumptive limit was determined. Similarly, no
wet-bottom tangential-fired units burning sub-bituminous were
identified as BART-eligible.
\20\ These limits reflect the design and technological
assumptions discussed in the technical support document for
NOX limits for these guidelines. See Technical Support
Document for BART NOX Limits for Electric Generating Units and
Technical Support Document for BART NOX Limits for Electric
Generating Units Excel Spreadsheet, Memorandum to Docket OAR 2002-
0076, April 15, 2005.
---------------------------------------------------------------------------
Because of the relatively high NOX emission rates of
cyclone units, SCR is more cost-effective than the use of current
combustion control technology for these units. The use of SCRs at
cyclone units burning bituminous coal, sub-bituminous coal, and
lignite should enable the units to cost-effectively meet
NOX rates of 0.10 lbs/mmbtu. As a result, we are
establishing a presumptive NOX limit of 0.10 lbs/mmbtu
based on the use of SCR for coal-fired cyclone units greater than
200 MW located at 750 MW power plants. As with the other presumptive
limits established in this guideline, you may determine that an
alternative level of control is appropriate based on your
consideration of the relevant statutory factors. For other cyclone
units, you should review the use of SCR and consider whether these
post-combustion controls should be required as BART.
For oil-fired and gas-fired EGUs larger than 200MW, we believe
that installation of current combustion control technology to
control NOX is generally highly cost-effective and should
be considered in your determination of BART for these sources. Many
such units can make significant reductions in NOX
emissions which are highly cost-effective through the application of
current combustion control technology.\21\
---------------------------------------------------------------------------
\21\ See Technical Support Document for BART NOX Limits for
Electric Generating Units and Technical Support Document for BART
NOX Limits for Electric Generating Units Excel Spreadsheet,
Memorandum to Docket OAR 2002-0076, April 15, 2005.
---------------------------------------------------------------------------
V. Enforceable Limits/Compliance Date
To complete the BART process, you must establish enforceable
emission limits that reflect the BART requirements and require
compliance within a given period of time. In particular, you must
establish an enforceable emission limit for each subject emission
unit at the source and for each pollutant subject to review that is
emitted from the source. In addition, you must require compliance
with the BART emission limitations no later than 5 years after EPA
approves your regional haze SIP. If technological or economic
limitations in the application of a measurement methodology to a
particular emission unit make a conventional emissions limit
infeasible, you may instead prescribe a design, equipment, work
practice, operation standard, or combination of these types of
standards. You should consider allowing sources to ``average''
emissions across any set of BART-eligible emission units within a
fenceline, so long as the emission reductions from each pollutant
being controlled for BART would be equal to those reductions that
would be obtained by simply controlling each of the BART-eligible
units that constitute BART-eligible source.
You should ensure that any BART requirements are written in a
way that clearly specifies the individual emission unit(s) subject
to BART regulation. Because the BART requirements themselves are
``applicable'' requirements of the CAA, they must be included as
title V permit conditions according to the procedures established in
40 CFR part 70 or 40 CFR part 71.
Section 302(k) of the CAA requires emissions limits such as BART
to be met on a continuous basis. Although this provision does not
necessarily require the use of continuous emissions monitoring
(CEMs), it is important that sources employ techniques that ensure
compliance on a continuous basis. Monitoring requirements generally
applicable to sources, including those that are subject to BART, are
governed by other regulations. See, e.g., 40 CFR part 64 (compliance
assurance monitoring); 40 CFR 70.6(a)(3) (periodic monitoring); 40
CFR 70.6(c)(1) (sufficiency monitoring). Note also that while we do
not believe that CEMs would necessarily be required for all BART
sources, the vast majority of electric generating units potentially
subject to BART already employ CEM technology for other programs,
such as the acid rain program. In addition, emissions limits must be
enforceable as a practical matter (contain appropriate averaging
times, compliance verification procedures and recordkeeping
requirements). In light of the above, the permit must:
Be sufficient to show compliance or noncompliance
(i.e., through monitoring times of operation, fuel input, or other
indices of operating conditions and practices); and
Specify a reasonable averaging time consistent with
established reference methods, contain reference methods for
determining compliance, and provide for adequate reporting and
recordkeeping so that air quality agency personnel can determine the
compliance status of the source; and
For EGUS, specify an averaging time of a 30-day rolling
average, and contain a definition of ``boiler operating day'' that
is consistent with the definition in the proposed revisions to the
NSPS for utility boilers in 40 CFR Part 60, subpart Da.\22\ You
should consider a boiler operating day to be any 24-hour period
between 12:00 midnight and the following midnight during which any
fuel is combusted at any time at the steam generating unit. This
would allow 30-day rolling average emission rates to be calculated
consistently across sources.
\22\ 70 FR 9705, February 28, 2005.
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[FR Doc. 05-12526 Filed 7-5-05; 8:45 am]
BILLING CODE 6560-50-P