Proposed Rule2024-17053
Air Plan Limited Approval and Limited Disapproval; Texas; Attainment Plan for the Rusk and Panola Counties 2010 Sulfur Dioxide Primary National Ambient Air Quality Standard Nonattainment Area; Finding of Failure To Attain the Primary 2010 One-Hour Sulfur Dioxide Standard for Rusk and Panola Counties
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
August 2, 2024
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing two actions in this notice. First, EPA is proposing to determine that the Rusk-Panola Counties, Texas nonattainment area failed to attain the 2010 1-hour primary sulfur dioxide (SO<INF>2</INF>) national ambient air quality standard (NAAQS) by the applicable attainment date of January 12, 2022. Second, EPA is proposing a limited approval and limited disapproval of the State Implementation Plan (SIP) revision for the Rusk-Panola 2010 1-hour SO<INF>2</INF> Primary NAAQS nonattainment area. EPA is proposing a limited disapproval because the SIP contains a force majeure clause that, if triggered, is such that the emissions limitations are not continuously applicable or enforceable. EPA is proposing limited approval because the SIP revision strengthens the SIP but does not fully meet the Act's requirements and provides for attainment, albeit not by the required deadline and with the exception of the force majeure clause. Under this limited approval action, if finalized, all provisions will be fully incorporated into the SIP. The limited disapproval, if finalized, will start sanctions clocks until the deficiency is corrected by the State and approved by EPA. EPA plans to address the deficiency in the SIP through a separate action promulgating a Federal Implementation Plan (FIP).
Full Text
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<title>Federal Register, Volume 89 Issue 149 (Friday, August 2, 2024)</title>
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[Federal Register Volume 89, Number 149 (Friday, August 2, 2024)]
[Proposed Rules]
[Pages 63117-63134]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-17053]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R06-OAR-2022-0311; FRL-12123-01-R6]
Air Plan Limited Approval and Limited Disapproval; Texas;
Attainment Plan for the Rusk and Panola Counties 2010 Sulfur Dioxide
Primary National Ambient Air Quality Standard Nonattainment Area;
Finding of Failure To Attain the Primary 2010 One-Hour Sulfur Dioxide
Standard for Rusk and Panola Counties
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing two
actions in this notice. First, EPA is proposing to determine that the
Rusk-Panola Counties, Texas nonattainment area failed to attain the
2010 1-hour primary sulfur dioxide (SO<INF>2</INF>) national ambient
air quality standard (NAAQS) by the applicable attainment date of
January 12, 2022. Second, EPA is proposing a limited approval and
limited disapproval of the State Implementation Plan (SIP) revision for
the Rusk-Panola 2010 1-hour SO<INF>2</INF> Primary NAAQS nonattainment
area. EPA is proposing a limited disapproval because the SIP contains a
force majeure clause that, if triggered, is such that the emissions
limitations are not continuously applicable or enforceable. EPA is
proposing limited approval because the SIP revision strengthens the SIP
but does not fully meet the Act's requirements and provides for
attainment, albeit not by the required deadline and with the exception
of the force majeure clause. Under this limited approval action, if
finalized, all provisions will be fully incorporated into the SIP. The
limited disapproval, if finalized, will start sanctions clocks until
the deficiency is corrected by the State and approved by EPA. EPA plans
to address the deficiency in the SIP through a separate action
promulgating a Federal Implementation Plan (FIP).
DATES: Written comments must be received on or before September 3,
2024.
ADDRESSES: Submit your comments, identified by Docket No. EPA-R06-OAR-
2022-0311, at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from <a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information whose disclosure is restricted by statute.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the web, cloud, or other
file sharing system). For additional submission methods, please contact
Andrew Lee, 214-665-6750, <a href="/cdn-cgi/l/email-protection#1d717878337c73796f786a337e5d786d7c337a726b"><span class="__cf_email__" data-cfemail="90fcf5f5bef1fef4e2f5e7bef3d0f5e0f1bef7ffe6">[email protected]</span></a>. For the full EPA public
comment policy, information about CBI or multimedia submissions, and
general guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
Docket: The index to the docket for this action is available
electronically at <a href="http://www.regulations.gov">www.regulations.gov</a>. While all documents in the
docket are listed in the index, some information may not be publicly
available in the electronic docket due to docket file size and/or file
type restrictions or content (e.g., modeling files, model code,
copyrighted material, CBI).
FOR FURTHER INFORMATION CONTACT: Andrew Lee, EPA Region 6 Office, Ozone
and Infrastructure section, 214-665-6750, <a href="/cdn-cgi/l/email-protection#e38f8686cd828d87918694cd80a3869382cd848c95"><span class="__cf_email__" data-cfemail="7d111818531c13190f180a531e3d180d1c531a120b">[email protected]</span></a>. We
encourage the public to submit comments via <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Please call or email the contact listed above if
you need alternative access to material indexed but not provided in the
docket. Modeling files and other files related to the alternative model
review are
[[Page 63118]]
available upon request. Copyrighted materials are available for review
in person at EPA Region 6 office in Dallas.
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
Table of Contents
I. Background
A. Rusk and Panola Counties SO<INF>2</INF> Nonattainment Area
B. SO<INF>2</INF> Nonattainment Area Plans
C. Attainment Demonstration for SO<INF>2</INF> Nonattainment
Area Plan
II. Proposed Determination--Finding of Failure To Attain the Primary
2010 One-Hour Sulfur Dioxide Standard
A. Applicable Statutory and Regulatory Provisions
B. Monitoring Network Considerations
C. Data Considerations and Proposed Determination
III. Limited Approval/Limited Disapproval
A. Force Majeure Provision Deficiency
B. Compliance Date Deficiency
C. Limited Approval
D. Limited Disapproval and Consequences
IV. Attainment Demonstration and Longer-Term Averaging
V. Review of Modeled Attainment Plan
A. Model Selection
B. Meteorological Data
C. Emissions Data
D. Receptor Grid
E. Emission Limits
F. Background Concentrations
G. Summary of Results
VI. Review of Other Plan Requirements
A. Emissions Inventory
B. Reasonably Available Control Measures and Reasonably
Available Control Technology (RACM/RACT)
C. New Source Review (NSR)
D. Reasonable Further Progress (RFP)
E. Contingency Measures
F. Conformity
VII. Proposed Action
VIII. Incorporation by Reference
IX. Environmental Justice Considerations
X. Statutory and Executive Order Reviews
I. Background
A. Rusk and Panola Counties SO2 Nonattainment Area
On June 22, 2010, the EPA published a new 1-hour primary
SO<INF>2</INF> NAAQS of 75 parts per billion (ppb), which is met at an
ambient air quality monitoring site (or in the case of dispersion
modeling, at an ambient air quality receptor location) when the 3-year
average of the annual 99th percentile of 1-hour daily maximum
concentrations does not exceed 75 ppb, as determined in accordance with
appendix T of 40 CFR part 50.\1\ On December 13, 2016, the EPA
designated portions of Rusk and Panola Counties, Texas as nonattainment
for the 2010 1-hour primary SO<INF>2</INF> NAAQS, effective January 12,
2017.\2\ The primary major source of emissions in the area is the
Martin Lake Steam Electric Station (Martin Lake), a coal-fired power
plant owned by Luminant Generation Company LLC (Luminant), a subsidiary
of Vistra Energy Corporation (Vistra). Section 191 of the CAA directs
states to submit SIPs for nonattainment areas to the EPA within 18
months of the effective date of the designation, i.e., by no later than
July 12, 2018 for the Rusk-Panola area. Under CAA section 192, these
SIPs are required to demonstrate that their respective areas will
attain the NAAQS as expeditiously as practicable, but no later than 5
years from the effective date of designation, i.e., January 12, 2022.
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\1\ See 75 FR 35520. See also 40 CFR 50.17(a)-(b).
\2\ See 81 FR 89870 See also 40 CFR part 81, subpart C.
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On August 10, 2020, the EPA published a ``Findings of Failure to
Submit State Implementation Plans Required for Attainment of the 2010
1-Hour Primary Sulfur Dioxide (SO<INF>2</INF>) National Ambient Air
Quality Standard (NAAQS)'' that found that Texas failed to submit the
required SO<INF>2</INF> attainment plan for the Rusk-Panola area by the
July 12, 2018 CAA deadline.\3\ This finding, effective on September 9,
2020, triggered 18-month and 24-month deadlines (March 9, 2022 and
September 9, 2022) under CAA section 179(a) for the imposition of
mandatory emission offsets and highway funding sanctions, respectively,
unless and until the state submits a SIP revision satisfying the CAA's
completeness criteria. Additionally, this finding triggered the CAA
section 110(c) requirement for EPA to promulgate a federal
implementation plan (FIP) within two years of the finding (September 9,
2022) unless the state submits and obtains EPA approval of a SIP
revision which corrects the deficiency before EPA promulgates a FIP.
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\3\ See 85 FR 48111
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On February 28, 2022, the Texas Commission on Environmental Quality
(TCEQ) submitted a Nonattainment SIP for the Rusk-Panola area. TCEQ's
SIP includes an Agreed Order for the Martin Lake facility in the area,
adopted on February 14, 2022, which includes emission limits and
monitoring requirements. On August 24, 2022, EPA determined that the
February 28, 2022 submittal was complete under 40 CFR part 51, App. V,
which stopped the mandatory emissions offsets sanctions that were in
effect and the 24-month sanction clock for the imposition of highway
funding sanctions.\4\ However, EPA's completeness determination did not
have an effect on EPA's FIP obligation, which is only satisfied by the
promulgation of a FIP or the full approval of a SIP.
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\4\ August 24, 2022 Completeness Determination Letter from David
Garcia, EPA Region 6 to Jon Niermann, TCEQ, available in the docket
for this action.
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B. SO2 Nonattainment Area Plans
SO<INF>2</INF> Nonattainment area SIPs must meet the applicable
requirements of CAA sections 110, 172, 191, and 192. The EPA's
regulations governing nonattainment area SIPs are set forth at 40 CFR
part 51, with specific procedural requirements and control strategy
requirements found at subparts F and G, respectively. Soon after
Congress enacted the 1990 Amendments to the CAA, the EPA issued
comprehensive guidance on SIPs, in a document entitled the ``General
Preamble for the Implementation of Title I of the Clean Air Act
amendments of 1990,'' published at 57 FR 13498 (April 16, 1992)
(General Preamble). Among other things, the General Preamble addressed
SO<INF>2</INF> SIPs and fundamental principles for SIP control
strategies. Id., at 13545-49, 13567-68. On April 23, 2014, the EPA
issued additional guidance for meeting the statutory requirements in
SO<INF>2</INF> SIPs in a document titled, ``Guidance for 1-Hour
SO<INF>2</INF> Nonattainment Area SIP Submissions'' (April 2014
SO<INF>2</INF> Guidance).\5\ In this guidance, the EPA describes how a
nonattainment area SIP can satisfy the following CAA requirements: an
accurate emissions inventory of current emissions for all sources of
SO<INF>2</INF> within the nonattainment area, an attainment
demonstration, demonstration of reasonable further progress (RFP),
implementation of reasonably available control measures (RACM)
(including reasonably available control technology (RACT)), an
approvable nonattainment new source review (NNSR) program, enforceable
emissions limitations and control measures, and adequate contingency
measures for the affected area.\6\
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\5\ ``Guidance for 1-Hour SO<INF>2</INF> Nonattainment Area SIP
Submissions'' available at: <a href="https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf">https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf</a>.
\6\ See section V. of ``Guidance for 1-Hour SO<INF>2</INF>
Nonattainment Area SIP Submissions''.
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Under CAA sections 110(l) and 193, the EPA may not approve a SIP
that would interfere with any applicable requirement concerning NAAQS
attainment and RFP, or any other applicable requirement under the Act.
[[Page 63119]]
C. Attainment Demonstration for SO2 Nonattainment Area Plan
CAA section 172(c)(1) requires a State's nonattainment area SIP to
provide for attainment of the NAAQS. 40 CFR part 51, subpart G further
delineates the control strategy requirements that SIPs must meet. The
EPA has long required that all SIPs and control strategies reflect four
fundamental principles of quantification, enforceability,
replicability, and accountability.\7\ Generally, SO<INF>2</INF>
attainment demonstrations consist of two components: (1) emission
limits and other control measures that assure implementation of
permanent, enforceable and necessary emission controls and (2) a
modeling analysis which demonstrates that the emission limits and
control measures provide for attainment as expeditiously as
practicable, but no later than the attainment date, and meets the
requirements of 40 CFR part 51, appendix W (Guideline on Air Quality
Models).
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\7\ See General Preamble at 13567-68.
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In all cases, the emission limits and control measures must be
accompanied by appropriate methods and conditions to determine
compliance and must be quantifiable (i.e., a specific amount of
emission reduction can be ascribed to the measures), fully enforceable
(specifying clear, unambiguous and measurable requirements for which
compliance can be practicably determined), replicable (the procedures
for determining compliance are sufficiently specific and non-subjective
so that two independent entities applying the procedures would obtain
the same result), and accountable (source specific limits must be
permanent and must reflect the assumptions used in the SIP
demonstrations).\8\
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\8\ See General Preamble at 13567-68.
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40 CFR part 51.112(a)(1) states that all applications of air
quality modeling shall be based on the applicable models specified in
the Guideline on Air Quality Models (Modeling Guideline). Appendix A to
the Guideline on Air Quality Models delineates EPA's preferred models
and other recommended techniques, as well as guidance for their use in
estimating ambient concentrations of air pollutants.<SUP>9 10</SUP> In
2005, the EPA promulgated AERMOD as the Agency's preferred near-field
dispersion modeling for a wide range of regulatory applications
addressing stationary sources (e.g., for estimating SO<INF>2</INF>
concentrations) in all types of terrain based on extensive
developmental and performance evaluation.\11\
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\9\ See 80 FR 45340 (July 29, 2015).
\10\ The EPA published revisions to the Guideline on Air Quality
Models on January 17, 2017. See 82 FR 5182 (January 17, 2017).
\11\ See 70 FR 68218 (November 9, 2005).
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The Modeling Guideline is periodically updated, with the most
recent revisions adopted in a Federal Register action on January 17,
2017, effective May 22, 2017.\12\ This most recent version of the
Modeling Guideline was in effect at the time Texas developed and
submitted its SIP to EPA.
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\12\ 82 FR 5182 (January 17, 2017) and 82 FR 14324 (March 20,
2017).
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While appendix A contains EPA's preferred models, 51.112(a)(2) also
provides that on a case-by-case basis, an alternative air quality model
may be used following written approval from EPA. In addition, the use
of an alternative model is subject to notice and opportunity for public
comment. The Modeling Guideline, in sections 4.2.2 and 4.2.2.1 and
appendix A, identifies AERMOD as EPA's preferred model for development
of a 1-hour SO<INF>2</INF> attainment demonstration SIP.
EPA's Modeling Guideline requires written approval finding that the
criteria in section 3.2 Alternative Models to utilize any modification
or substitution of EPA's preferred model, AERMOD, in a modeling
demonstration have been satisfied. The Modeling Guideline section
3.2.2(a) specifies that the determination of acceptability of an
alternative model is a Regional Office responsibility in consultation
with the Model Clearinghouse (MCH). Modeling Guideline section 3.2.2(b)
(sometimes referred to as ``Condition 2'') states the alternative model
shall be evaluated from both a theoretical and performance perspective
before regulatory use and outlines the three separate conditions that
may justify use of an alternative model.\13\ TCEQ's alternative model
request uses a statistical performance evaluation (Condition 2) to
justify AERMOD-HBP.\14\ A Condition 2 Alternative Model Request must
satisfy the Modeling Guideline requirements, including sections
3.2.2(b)(2), 3.2.2(d),\15\ and 3.2.2(e),\16\ While not specifically
cross-referenced, section 3.2.2(e) sets forth five conditions that
provide part of the framework and analytical process for evaluating
alternative model performance from both a theoretical and performance
perspective under 3.2.2 (b)(3)(sometimes referred to as Condition 3),
but that also provide guidance for what should be considered in any
alternative model approval in general, including for alternative model
approval under 3.2.2(b)(2) to help address the requirements of appendix
W 3.2.2(d) and as part of the elements of a modeling protocol and
submission of an alternative model request.
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\13\ See Modeling Guideline, section 3.2.2.(b)(1) (Condition 1)
(``If a demonstration can be made that the model produces
concentration estimates equivalent to the estimates obtained using a
preferred model''); section 3.2.2.(b)(2) (Condition 2) (``If a
statistical performance evaluation has been conducted using air
quality data and the results of that evaluation indicate the
alternative model performs better for the given application than a
comparable model in appendix A''); and section 3.2.2.(b)(3)
(Condition 3) (``If there is no preferred model'').
\14\ TCEQ submitted a letter dated May 24, 2021 from Ms. Tonya
Baer (Director of the Office of Air) to Mr. David Garcia (Air and
Radiation Division Director) of EPA Region 6 requesting approval of
an alternative model request for use AERMOD with Highly Buoyant
Plume (HBP) code modifications in the Rusk-Panola 2010 1-Hour
SO<INF>2</INF> NAAQS attainment demonstration. This document is
available in the Docket for this action.
\15\ App. W 3.2.2(d) states, ``For condition (2) in paragraph
(b) of this subsection [above], established statistical performance
evaluation procedures and technique for determining the
acceptability of a model for an individual case based on superior
performance should be followed, as appropriate. Preparation and
implementation of an evaluation protocol that is acceptable to both
control agencies and regulated industry is an important element in
such an evaluation.''
\16\ App. W 3.2.2(e) states, ``Finally, for condition (3) in
paragraph (b) of this subsection, an alternative model or technique
may be approved for use provided that: The model or technique has
received a scientific peer review; ii. The model or technique can be
demonstrated to be applicable to the problem on a theoretical basis;
iii. The databases which are necessary to perform the analysis are
available and adequate; iv. Appropriate performance evaluations of
the model or technique have shown that the model or technique is not
inappropriately biased for regulatory application; and v. A protocol
on methods and procedures to be followed has been established.''
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As required by the Modeling Guideline, EPA Region 6 has consulted
and coordinated with the EPA's Model Clearinghouse on TCEQ's
alternative model AERMOD-HBP request and received concurrence from the
Model Clearinghouse with EPA Region 6's approval of the AERMOD-HBP.\17\
While the Regional Administrators are delegated authority to issue such
approvals under section 3.2 of the Modeling Guideline, all alternative
model approvals will only be issued after consultation with the EPA's
MCH and formal documentation through a concurrence memorandum which
demonstrates that the requirements within section 3.2 for use of an
alternative model have been met.
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\17\ EPA Region 6 Concurrence request memorandum to MCH dated
July 11, 2024 and MCH Concurrence memorandum to EPA Region 6 dated
July 24, 2024 that are included in the docket for this action.
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In addition to the Modeling Guideline's requirements, EPA has
[[Page 63120]]
issued supplemental guidance on modeling for purposes of demonstrating
attainment of the 2010 SO<INF>2</INF> NAAQS as part of the April 2014
SO<INF>2</INF> Guidance titled ``appendix A. Modeling Guidance for
Nonattainment Areas'' (April 2014 SO<INF>2</INF> Guidance appendix A)
which is based on and is consistent with the Modeling Guideline. April
2014 SO<INF>2</INF> Guidance appendix A provides specific
SO<INF>2</INF> modeling guidance on the modeling domain, the source
inputs, assorted types of meteorological data, and background
concentrations.
As stated previously, attainment demonstrations for the 2010
SO<INF>2</INF> NAAQS must demonstrate future attainment of the NAAQS in
the entire area designated as nonattainment (i.e., not just at the
violating monitor) by using air quality dispersion modeling in
accordance with the Modeling Guideline and April 2014 SO<INF>2</INF>
Guidance to show that the mix of sources and enforceable control
measures and emission rates in an identified area will not lead to a
violation of the SO<INF>2</INF> NAAQS.\18\ For a short-term (i.e., 1-
hour) standard, the EPA has stated that dispersion modeling, using
allowable emissions and addressing stationary sources in the affected
area (and in some cases those sources located outside the nonattainment
area which may affect attainment in the area) is technically
appropriate, efficient, and effective in demonstrating attainment in
nonattainment areas because it takes into consideration combinations of
meteorological and emission source operating conditions that may
contribute to peak ground-level concentrations of SO<INF>2.</INF>
Estimated concentrations should include ambient background
concentrations, should follow the form of the standard, and should be
calculated as described in section 2.6.1.2 of the August 23, 2010,
clarification memo on ``Applicability of appendix W Modeling Guidance
for the 1-hr SO<INF>2</INF> National Ambient Air Quality Standard.''
\19\
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\18\ April 2014 SO<INF>2</INF> Guidance Pages 11-12.
\19\ See <a href="https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20100823_page_1-hr_so2_naaqs_psd_program.pdf">https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20100823_page_1-hr_so2_naaqs_psd_program.pdf</a>.
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II. Proposed Determination--Finding of Failure To Attain the Primary
2010 One-Hour Sulfur Dioxide Standard
A. Applicable Statutory and Regulatory Provisions
CAA section 179(c)(1) requires the EPA to determine whether a
nonattainment area has attained the NAAQS by the applicable attainment
date based on the area's air quality as of the attainment date. A
determination of whether an area's air quality meets applicable
standards is generally based upon the most recent three years of
complete, quality-assured monitoring data gathered at established state
and local air monitoring stations (SLAMS) in a nonattainment area and
entered into the EPA's Air Quality System (AQS) database. The accuracy
of that data is annually certified by monitoring agencies and the EPA
relied on that certified air monitoring data to calculate the design
values used to determine the area's air quality status.
Under EPA regulations in 40 CFR 50.17 and in accordance with 40 CFR
part 50 appendix T, the 2010 SO<INF>2</INF> NAAQS is met when the
design value is less than or equal to 75 ppb. Design values are
calculated by computing the three-year average of the annual 99th
percentile daily maximum one-hour average concentrations.\20\ An
SO<INF>2</INF> one-hour primary standard design value is valid if it
encompasses three consecutive calendar years of complete monitoring
data. A year is considered complete when all four quarters are
complete, and a quarter is complete when at least 75 percent of the
sampling days are complete. A sampling day is considered complete if 75
percent of the hourly concentration values are reported; this includes
data affected by exceptional events that have been approved for
exclusion by the Administrator.\21\ We note that when determining the
attainment status of SO<INF>2</INF> nonattainment areas, in addition to
ambient monitoring data, the EPA may also consider air quality
dispersion modeling and/or a demonstration that the control strategy in
the SIP has been fully implemented.\22\
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\20\ As defined in 40 CFR part 50, appendix T section 1(c),
daily maximum 1-hour values refer to the maximum one-hour SO 2
concentration values measured from midnight to midnight that are
used in the NAAQS computations.
\21\ See 40 CFR part 50, appendix T sections 1(c), 3(b), 4(c),
and 5(a).
\22\ EPA, April 23, 2014, Guidance for 1-Hour SO 2 Nonattainment
Area SIP Submissions (``SO<INF>2</INF> Nonattainment Area
Guidance''), page 49.
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With regard to the use of monitoring data for such determinations,
the EPA's SO<INF>2</INF> Nonattainment Area Guidance specifically notes
that ``if the EPA determines that the air quality monitors located in
the affected area are located in the area of maximum concentration, the
EPA may be able to use the data from these monitors to make the
determination of attainment without the use of air quality modeling
data.'' \23\ If there are no air quality monitors located in the
affected area or there are air quality monitors located in the area,
but analyses show that none of the monitors are located in the area of
maximum concentration, then air quality dispersion modeling will
generally be needed to estimate SO<INF>2</INF> concentrations in the
area. \24\ This language might be read to suggest that the EPA must
always assess whether the air quality monitors in the affected area are
located in the area of maximum concentration prior to using monitoring
data to determine area's attainment status. However, this language was
intended to refer to a situation where the EPA is considering making a
determination that the area has attained the NAAQS based on a finding
that all of the monitoring sites within the affected area had an
attaining design value for the relevant period.
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\23\ See page 50 of the SO<INF>2</INF> Nonattainment Area
Guidance.
\24\ See section VIII.A of the SO<INF>2</INF> Nonattainment Area
Guidance
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As described in section II.C of this notice, in this instance, the
monitoring sites in the Rusk-Panola SO<INF>2</INF> NAAs did not have
attaining design values for the relevant period. Consequently, even if
the monitoring sites are not located in the area of maximum
concentration, any monitors that would be located in the area of
maximum concentration could not record concentrations lower than those
recorded at the existing monitor at the Martin Creek site (EPA AQS Site
ID 48-401-1082). Accordingly, since the Martin Creek monitor was
violating the 2010 1-hour primary SO<INF>2</INF> NAAQS during the
relevant time period, it is not necessary to consider whether the
monitors are located in the area of maximum concentration in order to
determine that the Rusk-Panola area did not attain the 2010 1-hour
primary SO<INF>2</INF> NAAQS by the January 12, 2022, attainment date.
However, in any future assessment of whether these areas have attained
the NAAQS, the EPA may assess whether the monitors are located in the
area of maximum concentration and may also consider modeling and/or
control implementation information, as appropriate.
B. Monitoring Network Considerations
Section 110(a)(2)(B)(i) of the CAA requires states to establish and
operate air monitoring networks to compile data on ambient air quality
for all criteria pollutants. The EPA's monitoring requirements are
specified by regulation in 40 CFR part 58. These requirements are
applicable to state, and where delegated, local air monitoring agencies
that operate criteria pollutant monitors. In 40 CFR part 58, the EPA
specifies the minimum requirements for SO<INF>2</INF> monitoring sites
to be classified as state or local air monitoring stations (SLAMS)
[[Page 63121]]
or special purpose monitors (SPM). SLAMS and SPM produce data that are
eligible for comparison with the NAAQS and, therefore, the monitor must
be an approved federal reference method (FRM) or federal equivalent
method (FEM) per section 2 of appendix C to 40 CFR part 58. In the
Rusk-Panola Area, TCEQ operates a SPM monitor at Martin Creek site (EPA
AQS Site ID 48-401-1082, 9515 County Road 2181d).
C. Data Considerations and Proposed Determination
Under 40 CFR 58.15, monitoring agencies must annually certify that
prior year data collected by FRM and FEM at all SLAMS and special
purpose monitors (SPMs) meet EPA quality assurance requirements.
Monitoring agencies must also certify that the previous year of data
was completely submitted to AQS and is accurate to the best of their
knowledge.
The one-hour SO<INF>2</INF> design values, based on certified data
at the Martin Creek site (AQS ID: 48-401-1082) within the Rusk-Panola
nonattainment area for the 2019-2021 and 2020-2022 periods, are shown
in table 1.
Table 1--2019-2022 One-Hour SO2 Design Values for the Rusk-Panola Area
------------------------------------------------------------------------
Martin Creek
Years design value
(ppb)
------------------------------------------------------------------------
2019-2021............................................... 93
2020-2022............................................... 81
------------------------------------------------------------------------
The attainment date for the area was January 12, 2022. In order for
the EPA to determine that the area attained by the January 12, 2022,
attainment date based solely on air quality monitoring data, the design
value must be based upon complete, quality-assured monitored air
quality data from three consecutive years (2019-2021) at each eligible
monitoring site and equal to or less than the 75 ppb standard.
The one-hour SO<INF>2</INF> design value at the Martin Creek
monitoring site located within the Rusk-Panola area shows a violation
of the 1-hour primary SO<INF>2</INF> NAAQS with a concentration greater
than 75 ppb for the 2019-2021 design value, and thus, EPA is making the
determination that the Rusk-Panola area did not attain by its January
12, 2022, attainment date. We also note that the 2020-2022 design value
also shows a violation of the NAAQS.
Under CAA section 179(d)(2), if the EPA determines that an area did
not attain the NAAQS by the applicable deadline, the responsible air
agency has up to 12 months from the effective date of the determination
to submit a revised SIP for the area demonstrating attainment and
containing any additional measures that the EPA may reasonably
prescribe that can be feasibly implemented in the area in light of
technological achievability, costs, and any non-air quality and other
air quality-related health and environmental impacts as required.
According to CAA section 179(d)(3), this revised SIP is to achieve
attainment of the one-hour SO<INF>2</INF> NAAQS as expeditiously as
practicable, but no later than 5 years from the effective date of the
area's failure to attain (i.e., 5 years after the EPA publishes a final
action in the Federal Register determining that the nonattainment area
failed to attain the SO<INF>2</INF> NAAQS). In addition to triggering
requirements for a new SIP submittal, a final determination that a
nonattainment area failed to attain the NAAQS by the attainment date
would trigger the implementation of contingency measures adopted under
172(c)(9).
III. Limited Approval/Limited Disapproval
Under CAA sections 110(k)(3) and 301(a) and EPA's long-standing
guidance,\25\ the EPA is proposing a Limited Approval/Limited
Disapproval action. A limited approval is appropriate when a SIP
contains provisions that are SIP strengthening, but also contains a
non-severable deficiency that prevents EPA from granting a full
approval of the SIP. EPA's limited approval action allows the EPA to
codify SIP requirements, in this case, that would meet all requirements
of the CAA but for the noted force majeure and timely compliance
deficiencies. Under this limited approval, the area would make progress
toward attaining the NAAQS, even if the SIP cannot be fully approved as
meeting all applicable requirements for demonstrating NAAQS attainment
by the attainment date. EPA's limited disapproval action will ensure
that the deficient portions of the SIP submittal will be addressed,
either through an EPA approved SIP or a FIP. This subsection will
discuss the deficiencies identified in the SIP, the reasoning for and
impact of a limited approval and limited disapproval, and EPA's plan to
cure the deficiency.
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\25\ Processing of State Implementation Plan (SIP) Revisions,
EPA Memorandum from John Calcagni, Director, Air Quality Management
Division, OAQPS, to Air Division Directors, EPA Regional Offices I-X
(1992 Calcagni Memorandum) located at <a href="https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2_old/19920721_calcagni_sip_submittal_processing.pdf">https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2_old/19920721_calcagni_sip_submittal_processing.pdf</a>.
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Section 172(c)(6) of the CAA requires that nonattainment area SIP's
``include enforceable emission limitations, and such other control
measures means or techniques . . . . as well as schedules and
timetables for compliance, as may be necessary or appropriate to
provide for attainment of such standard in such area by the applicable
attainment date . . .''. Further, CAA section 302(k) defines ``emission
limitation'' to mean a requirement which limits the quantity, rate, or
concentration of air pollutant emissions on a continuous basis.
For an SO<INF>2</INF> attainment plan to be fully approvable, a
modeled attainment demonstration must be based on the maximum allowable
emissions permitted under the SIP's emission limitations and under
172(c)(6) those limitations must be practically and legally enforceable
and under 302(k) must be continuous. The same is true for the
demonstration of RACM/RACT, RFP, and contingency measures. Satisfying
the enforceability criteria ensures that NAAQS attainment will be
achieved via compliance with the SIP as adopted.
A. Force Majeure Provision Deficiency
The control strategy for the Rusk-Panola area is found in the
February 14, 2022, Agreed Order between TCEQ and Luminant for the
Martin Lake Facility incorporated into the SIP submittal. The Agreed
Order establishes emissions limits and control requirements for the
source which are necessary for the area to attain the NAAQS. However,
the Agreed Order also includes a force majeure provision which states
that, under a triggering event, the facility's failure to comply with
an emissions limitation or other provision is not a violation of the
Agreed Order.\26\ This provision allows exceedances of emission
limitations of unknown frequency, duration, and magnitude, and thus
impermissibly interferes with the ability to continuously enforce the
emissions limitations relied upon to provide for attainment. The
provision is not contemplated in the attainment modeling which relies
on the emissions limits being continuously and permanently applied,
and, therefore, makes the modeling not representative of actual air
quality in the area should this provision of the SIP be triggered. In
all cases, the emission limits and control measures must be
continuously applicable and accompanied by
[[Page 63122]]
appropriate methods and conditions to determine compliance and must be
quantifiable (i.e., a specific amount of emission reduction can be
ascribed to the measures), fully enforceable (specifying clear,
unambiguous and measurable requirements for which compliance can be
practicably determined), replicable (the procedures for determining
compliance are sufficiently specific and non-subjective so that two
independent entities applying the procedures would obtain the same
result), and accountable (source specific limits must be permanent and
must reflect the assumptions used in the SIP demonstrations).\27\ As
written, emissions associated with a force majeure event may increase
with unknown frequency, duration, and magnitude notwithstanding the
emission limitations because if the force majeure provision is
triggered it is no longer a violation to emit above the limitations set
in the SIP.
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\26\ See page 9 of the Agreed Order. The full text of the Agreed
Order can be found in the docket for this rulemaking action.
\27\ See General Preamble at 13567-68.
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Emissions reductions under this SIP submission are quantifiable,
except if the force majeure provision is triggered and the facility is
exempted from complying with emissions limitations to an unknown
extent. The emissions limitations outlined in the SIP are enforceable
by the state, EPA, and citizens, except in the case of a force majeure
event when lack of compliance with the emission limitations does not
constitute a violation and therefore cannot be enforced. There are no
clear, unambiguous, and measurable requirements for emissions that
occur once the force majeure provision is triggered. This could result
in excess emissions and periods of non-compliance which are ``not a
violation of [the] Agreed Order.'' \28\ These unaccounted emissions
could jeopardize the ability of the area to attain and maintain the
NAAQS while also cutting off the ability to enforce emissions
limitations necessary to attain. The provisions of this SIP are
replicable and are written sufficiently specific and non-subjective,
except for the force majeure provision that does not provide specific
procedures on how the provision should be interpreted, when compliance
should be exempt, or for how long compliance should be exempt.
Accountability is also an issue as the impact of triggering the force
majeure provision may exempt compliance with SIP requirements and lead
to unknowable, unaccounted for emissions associated with that event.
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\28\ See page 9 of the Agreed Order.
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If the control strategy in the SIP fails to adhere to these
principles, then the attainment demonstration relying on that control
strategy, that contemplates no such force majeure event, may no longer
be representative of the nonattainment area when the provision is
triggered. The force majeure provision impacts the enforceability of
the agreed order and thus, cannot be severed from the emissions
limitations contained in the Agreed Order and consequently impacts the
entirety of the SIP revision. The provision could interfere with the
SIP revision's ability to provide for attainment and maintenance of the
NAAQS, RFP, implementation of RACM/RACT, enforceable emission
limitations as necessary to provide for timely attainment, and
implementation of contingency measures. Therefore, the force majeure
provision included in the SIP submission warrants a limited
disapproval.
B. Compliance Date Deficiency
Second, EPA proposes a limited disapproval on the basis that the
date for compliance with the emission limitations as written in the
Agreed Order and SIP submittal is several months after the attainment
date for the area. Under CAA section 172(c)(6), the nonattainment plan
must include provisions as necessary or appropriate to provide for the
attainment by the applicable attainment date. Here, the applicable
attainment date for the Rusk-Panola Nonattainment area was January 12,
2022, but the Martin Lake Facility was not required to comply with all
of the emissions limitations set forth in the SIP submission's control
strategy until 180 days later, July 11, 2022. Therefore, because the
compliance date for the full control strategy is not until after the
attainment date for the area, EPA proposes a limited disapproval for
this SIP submission.
C. Limited Approval
Despite these deficiencies, and as further elaborated on in section
V with the full analysis of the attainment plan, EPA proposes that
absent this force majeure provision and the compliance date deficiency,
the SIP's attainment modeling, controls, emissions limitations, and
other requirements would otherwise be adequate to provide the needed
emission reductions to provide for attainment in the Rusk-Panola area.
Currently, there are no federally enforceable requirements that will
bring the Rusk/Panola area into attainment for the 2010 SO<INF>2</INF>
NAAQS. Therefore, despite the enforceability concerns, EPA is proposing
a limited approval to make these new requirements federally enforceable
as a SIP strengthening measure that will result in emissions reductions
and provide for progress towards attainment of the 1-hour primary
SO<INF>2</INF> NAAQS.
The Limited Approval encompasses the entire submittal, both the SIP
strengthening and deficient provisions, making all provisions federally
enforceable. The major source in the area will have to additionally
incorporate the control requirements and emissions limits prescribed in
the SIP into their CAA title V operating permit, which will also be
subject to federal enforcement.
D. Limited Disapproval and Consequences
On the basis of the deficiencies noted above, EPA is also proposing
a Limited Disapproval, which carries the same consequences as a full
disapproval. In accordance with CAA section 179, this Limited
Disapproval triggers an 18-month NSR emissions offset sanction clock
and a 24-month federal highway sanction clock. This action also
establishes a requirement under CAA section 110(c) for the EPA to
promulgate a FIP within two years. However, because of EPA's previous
Finding of Failure to Submit, EPA is past due to issue a FIP revision.
The sanctions are terminated when EPA fully approves a corrective SIP
revision. The FIP clock obligation is addressed when EPA issues a FIP
or fully approves the required SIP revision. Issuing a Limited
Approval/Limited Disapproval ensures that the area is subject to
federally enforceable requirements that will provide for progress
toward attainment, while simultaneously providing for the correction of
the deficient portion of the SIP submittal.
As stated previously in this section, the force majeure provision,
exempts enforcement of the emissions limitations and controls during a
specific type of event. To remedy this deficiency in the SIP, the EPA
plans to promulgate a FIP that reflects the control strategy included
in TCEQ's SIP submission but does not include the force majeure
provision.
IV. Attainment Demonstration and Longer-Term Averaging
In accordance with CAA section 172(c)(1), nonattainment SIPs must
include provisions that provide for attainment of the NAAQS. Please see
section I. Background, C. Attainment Demonstration for SO<INF>2</INF>
Nonattainment Areas subsection for a more detailed discussion of the
Attainment Demonstration requirements. An area can achieve attainment
by
[[Page 63123]]
implementing the appropriate control strategy identified to reduce
pollution at the requisite sources. 40 CFR part 51, subpart G further
delineates the control strategy requirements that SIPs must meet, and
EPA has long required that all SIPs and control strategies reflect the
four fundamental principles of quantification, enforceability,
replicability, and accountability. See General Preamble, at 13567-68.
Generally, for 1-hour standards control strategies include requirements
that are based on 1-hour averaging times as this is the most straight
forward way to ensure variability in the emission rate will not
interfere with attainment of the standard. However, EPA does allow
states to adopt requirements using longer-term averaging limits as long
as they can demonstrate they are comparably stringent to modeled 1-hour
critical emissions values (CEV) that would, if adopted as emission
limits, provide for attainment of the one-hour standard.
Texas' plan applies a 24-hour block average emission limit to
Martin Lake. Therefore, EPA is providing the following discussion of
its rationale for approving the use of longer-term average limits in
plans designed to provide for attainment. EPA's April 2014
SO<INF>2</INF> Guidance recommends that the emission limits be
expressed as short-term average limits (e.g., addressing emissions
averaged over one or three hours), but also allows for emission limits
with longer averaging times, up to 30 days, if certain criteria are
met. See April 2014 SO<INF>2</INF> Guidance, pp. 22 to 39. The guidance
recommends that, should states and sources utilize a longer-term
average limit, the limit should be set at an adjusted level that
reflects a comparable degree of stringency as the modeled 1-hour CEVs
(lb/hr and lb/MMBtu limits) {Note MMBtu is million British Thermal
Units{time} .
In evaluating this option, EPA considered the nature of the
standard, conducted detailed analyses of the impact of the use of up to
30-day average limits on the prospects for attaining the standard, and
carefully reviewed how best to achieve an appropriate balance among the
various factors that warrant consideration in judging whether a state's
plan provides for attainment. See April 2014 SO<INF>2</INF> Guidance at
appendices B, C and D.
As stated above and specified in 40 CFR 50.17(b), the 1-hour
primary SO<INF>2</INF> NAAQS is met at an ambient air quality
monitoring site when the 3-year average of the annual 99th percentile
of daily maximum 1-hour average concentrations is less than or equal to
75 ppb. In a year with 365 days of valid monitoring data, the 99th
percentile would be the fourth highest daily maximum 1-hour value. For
longer-term average limits, States must demonstrate with adequate
assurance that a longer-term averaging limit will have comparable
stringency as the one-hour average CEV and provide for attainment.
Critical to this demonstration is the frequency and magnitude of hourly
exceedances occurring under a longer-term average limit and the control
level needed to constrain those occurrences to provide for attainment
comparable to a strategy based on a one-hour emission standard. The
following is a synopsis of EPA's review of whether such plans provide
for attainment based on modeling of the one-hour CEV (1-hour CEV
emission rates lb/hr and lb/MMBtu) and in light of the NAAQS form for
determining attainment.
For plans relying on longer-term averaging limits, EPA's guidance
recommends that States establish a CEV based off of a continuously
applicable 1-hour emissions limit before determining their longer-term
averaging period and limits using fixed emission rates. The maximum
emission rate that would be modeled to result in attainment (i.e., in
an ``average year'' \29\ shows three, not four days with maximum hourly
levels exceeding 75 ppb, over three consecutive years) is labeled the
``critical emission value.'' The modeling process for identifying this
critical emission value considers the numerous variables that affect
ambient concentrations of SO<INF>2,</INF> such as meteorological data,
background concentrations, and topography. In the standard approach,
the state would then provide for attainment by setting a continuously
applicable 1-hour emission limit at this critical emission value.
---------------------------------------------------------------------------
\29\ An ``average year'' is used to mean a year with average air
quality. While 40 CFR 50 appendix T provides for averaging three
years of 99th percentile daily maximum values (e.g., the fourth
highest maximum daily concentration in a year with 365 days with
valid data), this discussion and an example below uses a single
``average year'' in order to simplify the illustration of relevant
principles.
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EPA recognizes that some sources have highly variable emissions,
for example, due to variations in fuel sulfur content and operating
rate, that can make it extremely difficult, even with a well-designed
control strategy, to ensure in practice that emissions for any given
hour do not exceed the critical emissions value. EPA also acknowledges
the concern that longer-term emission limits can allow short periods
with emissions above the critical emissions value, which, if coincident
with meteorological conditions conducive to high SO<INF>2</INF>
concentrations, could in turn create the possibility of a NAAQS level
exceedance occurring on a day when an exceedance would not have
occurred if emissions were continuously controlled at the level
corresponding to the critical emissions value. However, for several
reasons, EPA believes that the approach recommended in its April 2014
SO<INF>2</INF> Guidance document suitably addresses this concern.
First, from a practical perspective, EPA expects the actual emission
profile of a source subject to an appropriately set longer-term average
limit to be like the emission profile of a source subject to an
analogous 1-hour average limit. EPA expects this similarity because it
has recommended that the longer-term average limit be set at a level
that is comparably stringent to the otherwise applicable 1-hour limit
(reflecting a downward adjustment from the critical emissions value)
and that takes the source's emissions profile into account. As a
result, EPA expects either form of emissions limit to yield comparable
air quality.
Second, from a more theoretical perspective, EPA has compared the
likely air quality from a source that has maximum allowable emissions
under an appropriately set longer-term limit, to the likely air quality
from a source that has maximum allowable emissions under the comparable
1-hour limit. In this comparison, in the 1-hour average limit scenario,
the source is presumed at all times to emit at the critical emissions
level. In the longer-term average limit scenario, the source is
presumed occasionally to emit more than the critical emissions value
but on average, and presumably at most times, to emit well below the
critical emissions value. In an ``average year,'' compliance with the
1-hour limit is expected to result in three exceedance days (i.e.,
three days with an hourly value above 75 ppb) and a fourth day with a
maximum hourly value at 75 ppb. By comparison, for the source complying
with a longer-term limit, it is possible that additional exceedances
would occur that would not occur in the 1-hour limit scenario (if
emissions exceed the critical emissions value at times when meteorology
is conducive to poor air quality). However, this comparison must also
factor in the likelihood that exceedances that would be expected in the
1-hour limit scenario would not occur in the longer-term limit
scenario. This result arises because the longer-term limit requires
lower emissions most of the time since the limit is set well below the
critical emissions value, so a source complying
[[Page 63124]]
with an appropriately set longer term limit is likely to have lower
emissions at critical times than would be the case if the source were
emitting as allowed with a 1-hour limit.
As a hypothetical example to illustrate these points, suppose a
source that always emits 1,000 pounds of SO<INF>2</INF> per hour and
this results in air quality at the level of the NAAQS (i.e., results in
a design value of 75 ppb). Suppose further that in an ``average year,''
these emissions cause the 5 highest maximum daily average 1-hour
concentrations to be 100 ppb, 90 ppb, 80 ppb, 75 ppb, and 70 ppb. Then
suppose that the source becomes subject to a 30-day average emission
limit of 700 pounds per hour. It is theoretically possible for a source
meeting this limit to have emissions that occasionally exceed 1,000
pounds per hour, but with a typical emissions profile, emissions would
much more commonly be between 600 and 800 pounds per hour. This
simplified example assumes a zero-background concentration, which
allows one to assume a linear relationship between emissions and air
quality. A nonzero background concentration would make the mathematics
more difficult but would give similar results. Air quality will depend
on what emissions happen at what critical hours but suppose that
emissions at the relevant times on these 5 days are 800 pounds per
hour, 1,100 pounds per hour, 500 pounds per hour, 900 pounds per hour,
and 1,200 pounds per hour, respectively. This is a conservative example
because the average of these emissions, 900 pounds per hour, is well
over the 30-day average emission limit. These emissions would result in
daily maximum 1-hour concentrations of 80 ppb, 99 ppb, 40 ppb, 67.5
ppb, and 84 ppb. In this example, the fifth day would have an
exceedance that would not otherwise have occurred, but the third day
would not have an exceedance that otherwise would have occurred, and
the fourth day would have been below, rather than at, 75 ppb. In this
example, the fourth highest maximum daily concentration under the 30-
day average would be 67.5 ppb.
This simplified example encapsulates the findings of a more
complicated statistical analysis that EPA conducted using a range of
scenarios using actual plant data. As described in appendix B of EPA's
April 2014 Guidance, EPA found that the requirement for a lower long
term average emission limit is highly likely to yield better air
quality than is required with a comparably stringent 1-hour limit.
Based on analyses described in appendix B of its 2014 Guidance, EPA
expects that an emissions profile with maximum allowable emissions
under an appropriately set, comparably stringent 30-day average limit
is likely to produce the net effect of having a lower number of hourly
exceedances of the NAAQS level and better air quality than an emission
profile with maximum allowable emissions under a 1-hour emission limit
at the critical emissions value.\30\ This result provides a compelling
policy rationale for allowing the use of a longer averaging period, in
appropriate circumstances where the facts indicate this result can be
expected to occur.
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\30\ See also further analyses described in rulemaking on the
SO<INF>2</INF> attainment plan for Southwest Indiana. In response to
comments expressing concern that the emissions profiles analyzed for
appendix B represented actual rather than allowable emissions, EPA
conducted additional work formulating sample allowable emission
profiles and analyzing the resulting air quality impact. These
analyses provided further support for the conclusion that an
appropriately set longer term average emission limit in appropriate
circumstances can suitably provide for attainment. The rulemaking
describing these further analyses was published on August 17, 2020,
at 85 FR 49967. A more detailed description of these analyses is
available in the docket for that action, specifically at <a href="https://www.regulations.gov/document?D=EPA-R05-OAR-2015-0700-0023">https://www.regulations.gov/document?D=EPA-R05-OAR-2015-0700-0023</a>.
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The question then becomes whether this approach--which is likely to
produce a lower number of overall hourly NAAQS level exceedances even
though it may produce some unexpected exceedances above the critical
emission value--meets the requirement in section 110(a)(1) and
172(c)(1) for state implementation plans to ``provide for attainment''
of the NAAQS. For SO<INF>2</INF>, a variety of factors can cause a
well-designed attainment plan to fail and unexpectedly not result in
attainment. For example, this can occur if meteorology occurs that is
more conducive to poor air quality than was anticipated in the plan.
Therefore, the plan must provide an adequate level of confidence that
it will provide for attainment of the NAAQS. Additionally, when
evaluating longer-term average limits, EPA must weigh the likely net
effect on air quality. This evaluation must consider the risk that
occasions with meteorology conducive to high concentrations will have
elevated emissions leading to NAAQS level exceedances that would not
otherwise have occurred and must also weigh the likelihood that the
requirement for lower emissions on average will result in days not
having hourly exceedances that would have been expected with emissions
at the critical emissions value. Additional policy considerations,
including the desirability of accommodating real world emissions
variability without significant risk of NAAQS violations, are also
appropriate factors for EPA to weigh in judging whether a plan provides
for attainment with a reasonable degree of confidence. Based on these
considerations, especially given the high likelihood that a
continuously enforceable limit averaged over as long as 30 days,
determined in accordance with EPA's guidance, will result in
attainment, EPA believes as a general matter that such limits, if
appropriately determined, can reasonably be considered to provide for
attainment of the 2010 SO<INF>2</INF> NAAQS.
EPA's April 2014 SO<INF>2</INF> Guidance appendix B prescribes how
a state's SIP should develop and demonstrate that an appropriate
longer-term average limit provides for attainment. Development of
longer-term average limits starts with a determination of the 1-hour
emission limit that would provide for attainment (i.e., the critical
emissions value), establishment of an adjustment factor to determine
the (lower) level of the longer-term average emission limit that would
be estimated to have a stringency comparable to the otherwise necessary
1-hour emission limit, and application of the adjustment factor to the
emissions limits. The method for deriving an appropriate adjustment
factor uses a database of continuous emission data reflecting the type
of control that the source will be using to comply with the SIP
emission limits, which (if compliance requires new controls) may
require use of an emission database from another source. The
recommended method involves using this data to compute a complete set
of emission averages, computed according to the averaging time and
averaging procedures of the prospective emissions limit. In this
recommended method, the ratio of the 99th percentile among these long-
term averages to the 99th percentile of the 1-hour values represents an
adjustment factor that may be multiplied by the candidate 1-hour
emission limit to determine a longer-term average emission limit that
may be considered comparably stringent.\31\ The guidance also addresses
a variety of related topics, such as the potential utility of setting
supplemental emission limits, such as mass-based limits, to reduce the
likelihood and/or magnitude of elevated emission levels that might
occur under the longer-term emission rate limit.
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\31\ For example, if the critical emission value is 1,000 pounds
of SO<INF>2</INF> per hour, and a suitable adjustment factor is
determined to be 70 percent, the recommended longer term average
limit would be 700 pounds per hour.
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[[Page 63125]]
V. Review of Modeled Attainment Plan
This section discusses EPA's review and analysis of the modeled
attainment plan, including model selection, meteorological data,
emissions data, receptor grid, emissions limits, and background
concentrations. As discussed in detail in prior section III., EPA is
proposing that a limited approval and limited disapproval action is
necessary because, but for the presence of the force majeure provision
in the SIP submission, the modeled attainment plan satisfies the EPA's
CAA requirements and would adequately demonstrate the SIP requirements
will provide for attainment absent the force majeure provision.
TCEQ's SIP submittal relies on an alternative model, which modifies
the version of AERMOD approved for regulatory modeling. EPA reviewed
the TCEQ's alternative model and also performed its own additional
modeling analysis to determine whether the emission limits and control
measures in the State's SIP, absent the force majeure provision, would
provide for attainment in the Rusk-Panola area. The EPA's additional
modeling analysis used the Alternative Model AERMOD v.21112 with Highly
Buoyant Plume (TCEQ's alternative model AERMOD-HBP) and reflecting what
was done in the TCEQ modeling. EPA modeled two of the highest modeled
concentration scenarios utilizing the AERMOD-HBP v.21112 with HBP.
Those scenarios produced a modeled maximum design value, with
background concentration included, of 73.6 ppb of SO<INF>2</INF>,
confirming TCEQ's modeling results for these two scenarios. EPA also
ran these same two scenarios with the most recent version of AERMOD
v.23132 with HBP code. EPA has included the HBP code for scientific
testing and investigation as an alpha option in AERMOD v.23132, but it
is important to note that alpha options are for scientific
investigation and not approved for regulatory use. EPA compared the HBP
code in AERMOD v.23132 with TCEQ's AERMOD-HBP, and it appears to be the
same exact code. This modeling was performed by EPA to confirm that any
other changes in AERMOD between v.21112 and v.23132 would not result in
significant changes to TCEQ's attainment demonstration modeling, and
the maximum modeled results for these two scenarios were the same. This
modeling also confirms that the HBP code included in TCEQ's AERMOD-HBP
and the alpha option implemented in AERMOD v.23132 resulted in the same
maximum modeled concentrations. Additional, more detailed discussion of
the State's modeling and EPA's modeling of these two highest
concentration scenarios with both versions of AERMOD (TCEQ's v.21112
with HBP and EPA's v.23132 with non-regulatory alpha option HBP code)
are contained in the Technical Support Document (TSD) for this proposed
action. For EPA's alternative model review of the TCEQ's AERMOD-HBP see
the AERMOD-HBP TSD.
A. Model Selection
According to the Modeling Guideline, alternative models may only be
used instead of AERMOD with EPA review and approval. Texas' attainment
demonstration used an alternative model instead of the Modeling
Guideline preferred model, AERMOD v.21112.\32\ TCEQ's alternative model
modifies AERMOD's treatment of penetrated plumes which affects the
resultant modeled concentrations by delaying mix down of the penetrated
plume component under certain circumstances resulting in less emissions
mixing down to add to surface level concentrations. The modified code
added is referred to as the Highly Buoyant Plume Model Code \33\ and
the resultant alternative model is called AERMOD-Highly Buoyant Plume
(AERMOD-HBP). Along with the AERMOD-HBP, Texas used the regulatory
versions of AERMOD preprocessors (AERMET, AERMINUTE, AERSURFACE,
AERMAP, and Building Profile Input Program for PRIME (BPIPPRM)), and
where applicable, used the preprocessor's regulatory default
parameters.
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\32\ The most current version of AERMOD is version 23132, and
version 21112 was the version of AERMOD available at the time TCEQ
developed and adopted the SIP. See <a href="https://www.epa.gov/scram/air-quality-dispersion-modeling-preferred-and-recommended-models">https://www.epa.gov/scram/air-quality-dispersion-modeling-preferred-and-recommended-models</a>.
\33\ Weil, J.C., Corio, L.A., and Brower, R.P., 1997, A PDF
Dispersion Model for Buoyant Plumes in the Convective Boundary
Layer, Journal of Applied Meteorology. 36, 982-1003.Weil, J.C.,
January 2, 2020, New Dispersion Model for Highly-Buoyant Plumes in
the Convective Boundary Layer, Preliminary Draft v4.
---------------------------------------------------------------------------
Texas requested use of an alternative model in a letter dated May
24, 2021. Vistra's consultant, AECOM, performed initial dispersion
modeling for the Rusk-Panola area using AERMOD v. 19191. AECOM asserted
its initial modeling showed that AERMOD v. 19191 can overpredict
SO<INF>2</INF> concentrations relative to available SO<INF>2</INF>
observations at the Longview and Martin Creek monitors some of the
time.\34\ Based on AECOM's initial modeling, TCEQ and Vistra approached
EPA Region 6 in Fall 2020, that led to TCEQ requesting and having
discussions with EPA, TCEQ's contractor, Vistra, and Vistra's
contractor AECOM to develop an understanding of what information and
analysis were needed to support a potential alternative model request
with modified treatment of penetrated plumes. TCEQ formally requested
EPA's review and approval of an alternative model in a letter dated May
24, 2021.\35\ TCEQ's request did not include all of the necessary
components previously discussed between October 2020 through April 2021
for the EPA to complete an alternative model review. The EPA continued
to receive materials from TCEQ through August 2021, and EPA provided
some feedback and clarification on some technical analyses that were
needed for EPA to conduct its review of the alternative model request.
EPA did not receive all necessary components until August 2021. Those
components included the necessary information and modeling analysis to
enable EPA to perform a full review in accordance with the alternative
model review and approval guidelines. Several of these technical
analyses are based on the available data including: AERMOD v.21112
regulatory version and AERMOD-HBP modeling results comparisons using
actual emissions and meteorological data for the 2016-2020 period
coupled with available SO<INF>2</INF> monitoring data at the Martin
Creek and Longview monitors.\36\
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\34\ TCEQ SIP appendix M Alternative Model Documentation PDF,
page 222.
\35\ TCEQ submitted a letter dated May 24, 2021 from Ms. Tonya
Baer (Director of the Office of Air) to Mr. David Garcia (Air and
Radiation Division Director) of EPA Region 6 requesting approval of
an alternative model request for use AERMOD with Highly Buoyant
Plume (HBP) code modifications in the Rusk-Panola 2010 1-Hour
SO<INF>2</INF> NAAQS attainment demonstration. This document is
available in the Docket for this action.
\36\ Martin Creek monitor (AQS 484011082) is located
approximately 2 km to the north of Martin Lake EGU facility and
Longview Monitor (AQS 481830001) is located approximately 19 km to
the northwest of the Martin Lake EGU facility. While the Longview
monitor is relatively far away from the Martin Lake facility it was
found to have elevated SO<INF>2</INF> data when Martin Lake's
emissions were transported to the monitor, that was not
representative of maximum ambient concentrations from Martin Lake
facility emissions, was still useful to consider in evaluating the
alternative model request since there was limited monitoring data in
the area.
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EPA Region 6 performed a detailed analysis of the alternative model
request materials, including evaluating the theoretical rationale for
modifying how penetrated plumes are treated in AERMOD. TCEQ and EPA's
analysis centered on evaluation of the modeling results centered at the
two monitors in the area, the Martin Creek monitor and Longview
monitor, in order to compare modeled concentrations to monitored
[[Page 63126]]
values. The evaluation and technical analysis of regulatory AERMOD
results and the alternative model AERMOD-HBP results at receptors
placed at the two monitor locations were compared with the monitored
data for these two monitors using actual emissions, meteorology, and
monitored concentrations in the 2016-2020 timeframe for the Longview
monitor and 2018-2020 for the Martin Creek monitor. In addition to
TCEQ's submittal materials, EPA also performed several technical
analyses, including its own Cox-Tikvart statistical analysis to confirm
the conclusions. Overall, EPA's review of TCEQ's submittal materials
and EPA's own analyses confirmed TCEQ's conclusion that based on the
data available, AERMOD-HBP performed better than AERMOD in this one
case-specific and location-specific situation in the area around the
Martin Lake Electric Generating Facility (EGF) facility. Full details
of EPA's review and conclusions related to the alternative model
approval are provided in the ``EPA's Review of TCEQ's Alternative Model
Request of AERMOD with Highly Buoyant Plume Treatment (HBP)'' (AERMOD-
HBP TSD), included in the docket for this action.
Once EPA Region 6 modelers and Office of Air Quality Planning and
Standards' Air Quality Modeling Group (OAQPS-AQMG) modelers were in
agreement that the Alternative Model could be approved in accordance
with the Modeling Guideline section 3.2.2, EPA Region 6 sent a
memorandum with the detailed AERMOD-HBP TSD attached (dated July 11,
2024) to the Model Clearinghouse (part of OAQPS-AQMG) that proposed
approval of the Alternative Model and requested concurrence from the
Model Clearinghouse. The Model Clearinghouse sent a memorandum (dated
July 24, 2024) to EPA Region 6 concurring with the case specific
approval of the Alternative Model in this case-specific situation. The
AERMOD-HBP approval is limited specifically to only allow AERMOD-HBP to
be used in the attainment demonstration modeling for this Rusk-Panola
attainment demonstration. This approval limited to the specific
attainment demonstration at Martin Lake is based on the location and
situation-specific factors, including available monitoring data, that
were considered when evaluating this alternative model for this
specific case. The EPA notes that attempting to use this alternative
model for any other purposes at the Martin Lake facility, or any other
facility, would require a separate, stand-alone evaluation and approval
in accordance with EPA's alternative model requirements. Please see the
TSD, the Model Clearinghouse Memorandums, and EPA's AERMOD-HBP TSD for
more details.
B. Meteorological Data
The State's modeling utilized surface meteorological data obtained
from the Longview East Texas Regional Airport and upper air data from
the Shreveport, Louisiana station from 2015-2019. The Longview East
Texas Regional Airport is the closest National Weather Service (NWS)
site to the Martin Lake facility and monitor at Tatum County Road,
2181d Martin Creek Lake site (Air Quality System (AQS) 484011082),
approximately 19 kilometers (km) away and is representative of the
meteorology in the Rusk-Panola area due to its proximity. The
Shreveport, Louisiana NWS upper air site is the closest site of upper
air data. TCEQ processed the surface and upper air data using the
meteorological processing tools: AERMINUTE (v.15272), AERMET (v.21112),
and AERSURFACE (v.20060). AERMINUTE was used to include measured one-
minute wind averages, AERMET was used to generate meteorological data
files, and AERSURFACE was used to determine the surface characteristics
for the meteorological station. The current version of each
preprocessor at the time the modeling demonstration was performed was
AERMINUTE v.15272, AERMET v.21112, and AERSURFACE v. 20060. While the
most recent versions of AERMINUTE and AERSURFACE were used, AERMET has
been updated since the State conducted its modeling. However, based on
the changes that the EPA made to AERMET, we would not expect to see any
significant changes to modeling results if the data were processed with
the latest version of AERMET, and EPA finds that TCEQ's data are still
representative. EPA recommends using the closest NWS sites for surface
and upper air data if they are considered representative of the area
being modeled. In this situation, EPA concurs with the use of these two
sites for this modeling as meeting EPA's criteria as being nearby and
representative. EPA also finds that TCEQ adequately processed the data
in accordance with the Modeling Guideline and EPA's Guidance to
generate the necessary modeling data to be used in the AERMOD model
runs. Therefore, the EPA is proposing to find the selection and
processing of this data to be acceptable.
C. Emissions Data
The SIP revision identifies the Martin Lake facility as the primary
SO<INF>2</INF> source in the Rusk-Panola area. As there were no
monitors in the area at the time of designation, EPA relied on modeling
to designate the area and found that Martin Lake is likely producing
almost all, if not 100%, of the emissions causing the maximum modeled
design values that were above the NAAQS.\37\ This information is also
confirmed by review the of SO<INF>2</INF> sources in the Rusk-Panola
area provided in the SIP revision's emission inventory analysis. The
emissions inventory analysis shows that there are no other major
sources of SO<INF>2</INF> within the boundary of the Rusk-Panola area.
TCEQ appropriately modeled the maximum hourly emission rate for the
Martin Lake facility emission sources. The only nearby SO<INF>2</INF>
source with emissions greater than 100 tons per year within 50 km of
Martin Lake is the American Electric Power Pirkey Power Plant (Pirkey)
located approximately 17 km outside of the Rusk-Panola area boundary in
Harrison County. Since Pirkey is a background source outside of the
Rusk-Panola NAA that could potentially contribute to concentrations in
the Rusk-Panola NAA, pursuant to the Modeling Guideline table 8-1, a
hybrid of actual and allowable emission factors was used for emissions
from Pirkey in TCEQ's modeling for the Rusk-Panola area. The remainder
of the sources are captured by using monitoring data that is
representative of background concentrations. The inclusion of Pirkey
assures that Texas incorporated all sources in the modeling that are
considered to possibly create SO<INF>2</INF> concentrations and/or
concentration gradients anywhere in the Rusk-Panola NAA that are not
represented by the background monitoring data.
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\37\ See 81 FR 45039.
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The other facility, Pirkey, that is located outside of the Rusk-
Panola area included in the modeling, is not located in a direction
such that it can contribute to the maximum SO<INF>2</INF>
concentrations in the Rusk-Panola area (not upwind), and thus, would
have a negligible impact on maximum modeled concentrations within the
Rusk-Panola area. Therefore, TCEQ did not require new SO<INF>2</INF>
emission limits on Pirkey. EPA has reviewed the facility's data and
notes that the Pirkey facility is 17 km away from Martin Lake and the
nearby Martin Creek monitor near Tatum County Road, and thus adding
emission limits to Pirkey are not critical to demonstrating attainment
in the area. EPA concurs with TCEQ's
[[Page 63127]]
approach of including Martin Lake (allowable emissions modeled) and
Pirkey (hybrid of actual and allowable emission related factors to
generate emissions modeled) emission sources, which comports with EPA's
Modeling Guideline, including table 8-1, that provides guidance on what
sources to include in the modeling and whether to model actuals or
allowable emissions.
TCEQ used site specific building and stack data and modeled all
stacks in Martin Lake at the lesser of actual stack height or Good
Engineering Practice (GEP) stack height. The State's modeling included
building downwash influences for all sources except for Pirkey because
the effects of downwash from Pirkey are localized and would not affect
modeled concentrations in the Rusk-Panola area. The EPA has determined
that the SIP's selection of sources and preprocessing of that source
data satisfies the requirements of the Modeling Guideline. For a more
detailed analysis and conclusions on what sources were included in the
modeling and how they were modeled, see the TSD.
As discussed in the TSD, Martin Lake was identified as the primary
contributor to NAAQS violations in the Rusk-Panola area. Martin Lake is
an EGF, with four point sources and one fugitive area source for
SO<INF>2</INF>; the four point sources consist of three EGF boiler unit
stacks and one combined stack for two auxiliary boilers. Modeling
indicated emission reductions for Martin Lake were necessary to provide
for attainment, and based on the modeling emission limitations were
developed and included in the Agreed Order between TCEQ and Luminant
that was submitted as part of this SIP revision. The modeling covers 42
operating scenarios in total. These different scenarios were developed
based on a combination of an emissions limit specific to each EGF
boiler, an overall emission cap on emissions from the three main EGF
boiler stacks, and four different operating loads. There are four
different operating loads for the EGF boilers: (1) high load, (2)
medium load, (3) low load, and (4) a maintenance, startup and shutdown
(MSS) load. TCEQ modeled control measures using the critical emission
value of 8,208 lbs/hour as the one-hour averaging period emission cap
for the three EGF boilers that correlates with the Agreed Order's
longer-term averaging emissions limit of 7,469 lb/hr over a 24-hour
block averaging period. TCEQ's modeling also modeled the critical
emission value of 0.33 lb/MMBtu limit for each boiler that correlates
to the agreed order limit of 0.32 lb/MMBtu limit on a 24-hour block
averaging period for each boiler. TCEQ developed the 42 different
emission scenarios based on these limits as discussed in the TSD. For
more detailed discussion and evaluation of the Agreed Order 24-hour
block averaging limits and the critical emission value comparably
stringent 1-hour averaging limitation values used in the modeling, see
section V.E. In conclusion, the EPA is proposing to find that Texas'
choice of included sources and the scenarios modeled to cover the
potential range of operating scenarios that could occur with the new
limits in place to be appropriate and inclusive of worst-case
scenarios, in the absence of the force majeure provision.
D. Receptor Grid
Within AERMOD, air quality concentration results are calculated at
discrete locations identified by the user; these locations are called
receptors. Receptors are placed in areas and outside the plant
boundaries and areas within the plant boundary where the public has
access. Areas within the plant where public access is restricted, are
not considered ambient air for the purposes of compliance with NAAQS.
TCEQ's modeling domain for this demonstration consisted of a 25.5 km by
24.5 km rectangular area centered around Martin Lake with three nested
receptor grids. TCEQ placed receptors within and outside the Rusk-
Panola nonattainment area: (1) receptors at 25 meter (m) spacing along
the non-ambient air fence/boundary lines, (2) the innermost grid
spanning 0 to 3 km from the center point, encompassing Martin Lake,
with 50m spacing between receptors; (3) the middle-nested grid extended
from 3 km to 9 km, with 100 m spacing between receptors; and (4) the
outermost grid, which extends beyond the nonattainment boundary covers
the rest of the modeled domain, had 500 m spacing. The TCEQ, after
discussions with EPA and Vistra, removed receptors from the grid found
within the property owned and controlled (public access is restricted)
by Vistra,\38\ Vistra restricts public access to this area through
fencing, posting, and patrolling. Again, the air in the area controlled
by Vistra is considered non-ambient air relative to its own emissions,
and thus, they are not required to place receptors within these
boundaries. Receptors with 25m spacing were also added along a section
of public road within Vistra's property, and an additional receptor was
placed at the location of the Martin Creek monitor. TCEQ determined
receptor elevations using AERMAP in its modeling. EPA proposes that the
receptor grid is consistent with EPA's Modeling Guideline and is
adequate for demonstrating attainment within the NAA and the
immediately surrounding area in this attainment demonstration modeling.
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\38\ See TCEQ's SIP appendix L--``Documentation from Vistra
Energy Corporation for Property Boundaries''.
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E. Emission Limits
As part of its control strategy for the Rusk-Panola area, Texas
entered an Agreed Order with Luminant set emissions limitations for the
Martin Lake facility, adopted on February 14 2022, pursuant to
Sec. Sec. 382.011, 382.012, 382.023, and 382.024 of the Texas Clean
Air Act, Texas Health & Safety Code, Chapter 382, and the CAA. TCEQ
incorporated the Agreed Order as part of its SIP revision submittal as
a source-specific SIP revision seeking to establish federally
enforceable emission limits. The limits in table 2 are hourly limits,
and compliance with the limits is determined using the longer-term 24-
hour block averaging period.
As stated in subsection C of this notice, there are no other major
sources of SO<INF>2</INF> within the nonattainment area that could
contribute to nonattainment in the Rusk-Panola area. The Agreed Order
set the compliance date for emission limits as ``the date by which the
State of Texas is required to demonstrate compliance with the 2010 1-
hour SO<INF>2</INF> NAAQS for the Rusk-Panola SO<INF>2</INF>
Nonattainment Area.'' This means that the compliance date for the
Agreed Order would be the attainment date, January 12, 2022 for limits
other than the lb/MMBtu limits, which require compliance 180 days later
(July 11, 2022).\39\ EPA proposes to find that the source specific
emissions limits as laid out in the Agreed Order submitted with this
SIP revision would be sufficient, based on the above described modeling
and recognizing the longer than 1 hour averaging period, to provide for
attainment in the Rusk-Panola area absent the force majeure provision.
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\39\ Vistra and TCEQ signed the Agreed Order on January 19,
2022. TCEQ formally adopted the Agreed Order on February 14, 2022.
[[Page 63128]]
Table 2--Martin Lake Agreed Order Emission Limitations
----------------------------------------------------------------------------------------------------------------
Source ID Source description Sulfur Dioxide (SO2) limit
----------------------------------------------------------------------------------------------------------------
S-1, S-2, S-3......................... EGF Boiler Units...................... II.a.(i)
(1) Burn only subbituminous
coal, No. 2 fuel oil, or
natural gas;
(2) limit the firing rate (when
fired) for all three EGF boiler
units to a combined rate not to
exceed 27,000 million British
thermal units (MMBtu) per hour
(the firing rate is an
operating cap for all three EGF
boiler units combined); and
(3) Optimize the FGD systems to
ensure compliance with a
combined SO2 emission rate not
to exceed 7,469 lb/hr on a
block 24-hour average basis for
the three EGF boiler units (the
7,469 lb/hr is an emission cap
for all three EGF boiler units
combined). The emission cap of
7,469 lb/hr applies at all
times when fuel of any type is
fired in any EGF boiler unit.
(ii) . . . the Company shall
ensure compliance with an SO2
emission rate not to exceed
0.32 lb/MMBtu on a block 24-
hour average basis for each EGF
boiler unit. This emission rate
applies at all times when fuel
of any type is fired in any EGF
boiler unit.
S-1A and B............................ Auxiliary Boilers..................... II.b.
(i) Fire only No. 2 fuel oil
with a sulfur content of 0.10%
by weight or less;
(ii) Not exceed an SO2 emission
rate of 51.46 lbs/hr on a one-
hour basis and 22.54 tpy on an
annual basis, combined for the
two Auxiliary Boilers (the
51.46 lbs/hr and 22.54 tpy are
emission caps for the two
auxiliary boilers combined);
and
(iii) Comply with a 10 percent
annual capacity factor for each
of the two Auxiliary Boilers.
Annual capacity factor is the
ratio between the actual heat
input from all fuels burned
during a calendar year and the
potential heat input had the
boiler been operated for 8,760
hours during a year at the
maximum steady state design
heat input capacity. The 10
percent annual capacity factor
limit corresponds to a heat
input of 219,000 MMBtu per
calendar year, per Auxiliary
Boiler.
(iv) The Company shall monitor
the sulfur content of the
liquid fuel in accordance with
fuel sampling requirements
specified in 40 CFR part 75,
appendix D, 2.2 Oil Sampling
and Analysis.
----------------------------------------------------------------------------------------------------------------
1. Enforceability
An attainment plan must include emission limits that provide for
attainment and that are: quantifiable, fully enforceable, replicable,
and accountable.\40\ Full enforceability includes the ability to
enforce emissions limitations by the state, the EPA, or by private
citizens through a citizen suit.\41\ As discussed in detail in section
III. of this notice, EPA proposes to find that the force majeure
provision included in the SIP submission interferes with enforceability
such that the Agreed Order and attainment plan may not be fully
approved as meeting the requirements of CAA sections 110, 172, 191 and
192.
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\40\ See General Preamble at 13567-68.
\41\ 42 U.S.C. 7604.
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2. Longer-Term Average Emission Limits
As noted in section IV. and section V.C, the Texas SIP is using
longer-term lb/hr and lb/MMBtu emission limits with 24-hour block
averaging compliance limits for three EGF boilers at the Martin Lake
facility. Therefore, the critical emissions values are the modeled
emission rates/limits based on 1-hour averaging period and serve as the
basis for developing emission rate limits for longer averaging period
and the limits used in the attainment modeling for the area. Modeled
emission rates of 8,208 lb/hr and 0.33 lbs/MMBtu (one hour averaging
period) were calculated by Vistra to convert to 7,469 lbs/hour and 0.32
lbs/MMBtu averaged over a 24-hour block period. Martin Lake will be
switching fuels from lignite and lignite blend operations to
subbituminous coal, and therefore, Vistra and Texas evaluated other
similar subbituminous coal fired units elsewhere in Texas with similar
SO<INF>2</INF> control devices that would be more representative of
operating conditions rather than comparing to the past performance of
the Martin Lake units operating on lignite coal. As such, Vistra and
Texas determined that the NRG Limestone units would be appropriate
sources to derive an adjustment factor to apply to the EGF boilers at
Martin Lake due to the use of subbituminous coal at the NRG Limestone
units and both facilities have wet FGD controls. In the SIP, Texas
utilized three years of NRG Limestone (located near Jewett, Texas)
emissions data from October 2018 through September 2021 to conduct the
variability analysis, which coincides with when NRG Limestone burned
only subbituminous coal. Texas employed the method detailed in our 2014
SO<INF>2</INF> Guidance appendices B, C, and D for deriving an
appropriate adjustment factor to adjust the lb/hr modeled emission
rates and the lb/MMBtu emission limit, to result in equivalent 24-hour
block averaging lb/hr and lb/MMBtu emission limits. Texas followed
EPA's guidance and evaluated the historic 1-hour 99th percentile of
SO<INF>2</INF> emissions information (lb/hr and lb/MMBtu) against the
99th percentile 24-hour block average for the lb/hr and lb/MMBtu data
to derive the appropriate adjustment factors of 0.91 for lb/hr and 0.97
lb/MMBtu. These factors were used by Texas to derive the emission
limits of 7,469 lbs/hour and 0.32 lbs/MMBtu averaged over a 24-hour
block period that were included in the Agreed Order for Martin Lake.
EPA has reviewed TCEQ's information supporting the 24-hour block
averaging limits and is proposing to find the analysis acceptable and
that these represent comparably stringent limits that would, absent the
force majeure clause be protective of the NAAQS. For a more detailed
discussion of our analysis please see the TSD prepared for this action.
F. Background Concentrations
To develop background concentrations for the NAA, Texas relied on
2015-2019 SO<INF>2</INF> data from the Midlothian OFW monitor in Ellis
County (CAMS C52), approximately 220 km west of the NAA.\42\ Texas
determined that there were no representative nearby monitors to capture
background concentrations, as the nearby monitors were all
SO<INF>2</INF> Data Requirements Rule (DRR) monitors sited to capture
the impacts of major SO<INF>2</INF> sources or other monitors with data
significantly impacted by large SO<INF>2</INF> sources (e.g., Longview
monitor in Gregg County is 19 km from Martin Lake but Martin Lake's
emissions have historically had a large impact on this
[[Page 63129]]
monitor's data). Therefore, Texas used a monitor located away from the
source but still considered to be representative of background
concentrations in the area. The Midlothian OFW monitor in Ellis County,
Texas was chosen as it had complete SO<INF>2</INF> Design Values (DVs)
for the 2015 through 2019 period and had a more stable DV across recent
years.
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\42\ Data is available in EPA's Air Quality System (AQS).
(<a href="https://www.epa.gov/aqs">https://www.epa.gov/aqs</a>).
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A fixed background concentration of 15.72 [micro]g/m\3\ was added
to modeled concentrations to result in maximum modeled concentrations
for all 42 scenarios. These background values are representative of the
contribution due to other sources within the Rusk-Panola area and
surrounding areas that were not explicitly modeled combined with
regional continental background in this area. See the TSD for
additional information. Using this approach, the EPA is proposing to
find the State's treatment of SO<INF>2</INF> background levels to be
acceptable for adding to modeled concentrations to represent background
SO<INF>2</INF> levels in this attainment demonstration modeling.
G. Summary of Results
The State's alternative modeling demonstration, which incorporates
emissions scenarios based on the February 14, 2022, Agreed Order
emission limits for the Martin Lake facility but recognizing the longer
than 1 hour averaging time, resulted in modeled concentrations below
the 1-hour primary SO<INF>2</INF> NAAQS using the alternative model
AERMOD-HBP. As noted, EPA Region 6 proposed approval and obtained
concurrence from the Model Clearinghouse for the use of the alternative
model for this specific application. TCEQ modeled 42 different
scenarios representing the range of operations, emissions, and
dispersion that could occur, incorporating the Agreed Order's required
emission limits. These 42 modeled scenarios had maximum ambient air
modeled DVs ranging from 40 ppb to 73.6 ppb (104.8 [micro]g/m\3\ to
192.8 [micro]g/m\3\) that all demonstrated attainment of the 1-hour
SO<INF>2</INF> NAAQS, without accounting for the possible excused non-
compliant emissions periods under the force majeure provision.\43\
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\43\ TSD pages 24-26.
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As part of EPA's modeling review, EPA modeled the two scenarios
that resulted in the highest maximum DV of 73.6 ppb using the AERMOD-
HBP alternative model (based on AERMOD v.21112), and the results
duplicated TCEQ's results with the same maximum modeled design values.
The only differences between EPA's model runs and TCEQ's model runs for
these two scenarios were that EPA modeled all of the receptors in one
AERMOD run using a single CPU processor, and EPA relied on AERMOD to
generate the maximum DVs with inclusion of the background
concentrations instead of all of the post-processing steps that TCEQ
performed. TCEQ modified a prior version of AERMOD that was the current
version at the time TCEQ developed their SIP, version v.21112. Since
TCEQ submitted their SIP, there have been two updates to AERMOD, and
the most recent version is AERMOD v.23132. EPA ran these same two
scenarios using the current version of AERMOD, v.23132, with the non-
regulatory alpha option HBP code (same as TCEQ's HBP code). The EPA has
included the HBP code in AERMOD as an alpha option that is only for
scientific testing and investigation, and the HBP code is not approved
for any regulatory modeling. EPA did these model runs to see if the
current version of AERMOD with the alternative HBP model code (not
approved for use in regulatory modeling) would still result in the same
maximum DV values obtained using the AERMOD HBP Alternative Model
(AERMOD v.21112 with HBP code). This test is to verify that the code
changes in the regulatory version of the model (non-HBP code) did not
result in any model concentration changes. The more recent version of
AERMOD with the non-regulatory HBP code included resulted in the same
modeled results as TCEQ's AERMOD v.21112 with HBP code. This test
confirms that the updates in the regulatory version of AERMOD between
v.21112 and v.23132 do not result in any differences in the maximum
design value when both AERMOD versions were run with the non-regulatory
alternative model code HBP.
With the exception of the HBP code that is an alternative model,
EPA's review of the rest of TCEQ's modeling components indicated that
TCEQ used the regulatory AERMOD preprocessors (AERMET, AERMINUTE,
AERSURFACE, AERMAP, and Building Profile Input Program for PRIME
(BPIPPRM) for building/structure downwash). TCEQ's submitted modeling,
where applicable, used the regulatory default parameters, and the
options and settings for AERMOD and the processors used are acceptable.
TCEQ broke up the receptor grid into multiple runs and post-processed
the results outside of AERMOD, which complicated review. The EPA
reviewed model input and output files for all 42 modeling runs and
modeled two of the scenarios that had the highest design value and
confirmed that TCEQ's approach resulted in the same maximum modeled
concentration results. For more detailed information, explanation, and
analysis of TCEQ's modeling please see the following documents included
in this docket: TSD, AERMOD-HBP TSD, Model Clearing House memoranda.
After reviewing Texas' attainment demonstration and conducting
additional modeling runs, the EPA agrees that Texas' submittal and
supplemental materials, along with the Agreed Order (February 14, 2022)
limits, constitute an attainment plan that would strengthen the SIP and
sufficiently reduce emissions to meet the NAAQS in the Rusk-Panola
area, but for the force majeure provision. However, due to the untimely
compliance date for aspects of the attainment plan and the impacts of
the force majeure provision of the Agreed Order on all of the Agreed
Order's emission limits for the Martin Lake facility, Texas' attainment
plan is insufficient to fully provide for attainment in the Rusk-Panola
area or fully meet the requirements of CAA sections 110, 172, 191 and
192. EPA therefore proposes to issue a limited approval and limited
disapproval for this attainment plan SIP revision. See section III.
Limited Approval/Limited Disapproval for additional discussion. We
therefore propose to determine that, absent the force majeure
provision, Texas' plan would provide for attaining air quality under
the 2010 1-hour primary SO<INF>2</INF> NAAQS in the Rusk-Panola
nonattainment area.
VI. Review of Other Plan Requirements
Section VI includes EPA's review of the following SIP elements:
Emissions inventory, RACM and RACT, NSR, RFP, contingency measures, and
conformity. EPA proposes that the SIP adequately satisfies the
requirements for a baseline emissions inventory and nonattainment NSR,
but due to the presence of the force majeure provision affecting the
enforceability of the limits relied upon in the attainment
demonstration, cannot otherwise meet the requirements of CAA sections
110, 172, 191 and 192, particularly for RACM/RACT, RFP, emissions
limits necessary to provide for attainment, and contingency measures.
A. Emissions Inventory
The emissions inventory and source emission rate data for an area
serve as the foundation for air quality modeling and other analyses
that enable states to: (1) estimate the degree to which different
sources within a nonattainment area contribute to
[[Page 63130]]
violations within the affected area; and (2) assess the expected
improvement in air quality within the nonattainment area due to the
adoption and implementation of control measures. A nonattainment SIP
must include a comprehensive, accurate, and current inventory of actual
emissions from all sources of SO<INF>2</INF> in the nonattainment area
as well as any sources located outside the nonattainment area which may
affect attainment in the area. See CAA section 172(c)(3). In its
submittal, Texas included a current emissions inventory for the Rusk-
Panola area covering the 2017-2022 period, which can be found below at
table 3.
The State of Texas compiles a statewide emissions inventory for
stationary sources in accordance with Texas regulations at 30 Texas
Administrative Code (TAC) Sec. 101.10, CAA requirements, and EPA
guidance. The submitted data is then reviewed for quality assurance
purposes and stored in the State of Texas Air Reporting System (STARS)
database. In its submittal, Texas confirmed that stationary point
sources (i.e., Martin Lake) comprised over 99% of the SO<INF>2</INF>
emissions in the Rusk-Panola area. Texas determined the forecasted 2022
emissions for Martin Lake through historical point source heat input
and a future year emissions limit that accounts for enforceable
emissions reductions as required in the Agreed Order. According to the
2014 SO<INF>2</INF> Guidance, nearby sources outside the NAA (Pirkey)
should also be included in the emissions inventory.
TCEQ chose the year 2017 as the base year for its analyses as the
most complete and representative record of annual SO<INF>2</INF>
emissions because (1) it was the most recent periodic inventory year
available and (2) it was also the year that the EPA designated the
Rusk-Panola area as nonattainment for the 2010 SO<INF>2</INF> NAAQS.
The 2017 baseline area source emissions inventories were developed
in accordance with the requirements of the Air Emissions Reporting
Requirements (AERR) rule and developed using EPA-generated EIs, TCEQ-
contracted projects, TCEQ staff projects, and 2014 EIs by applying
growth factors derived from different sources.\44\ TCEQ also developed
non-road and on-road mobile source emissions inventories by using EPA's
mobile source emissions models, Texas-specific utility of the EPA
mobile source models, and EPA-approved methods and guidance.
---------------------------------------------------------------------------
\44\ Eastern Research Group (ERG) study data, the Economy and
Consumer Credit Analytics website (<a href="https://www.economy.com/default.asp">https://www.economy.com/default.asp</a>), and the United States Energy Information
Administration's Annual Energy Outlook publication.
---------------------------------------------------------------------------
A summary of the State's submitted emissions inventory is provided
in the following table:
---------------------------------------------------------------------------
\45\ AEP Pirkey Power Plant was retired in Spring of 2023.
Table 3-1--Rusk-Panola Nonattainment Area SO2 Emissions in Tons per Year (TPY)
----------------------------------------------------------------------------------------------------------------
Agreed order
2017 Base 2018 2019 2022 federally
Source category year Reported Reported Attainment enforceable
reported emissions emissions year maximum
emissions emissions emissions
----------------------------------------------------------------------------------------------------------------
Point--Martin Lake.......................... 36,441.46 56,198.55 46,549.50 22,269.31 32,736.76
Non-point................................... 0.31 N/A N/A 0.43 N/A
On-road Mobile.............................. 0.14 N/A N/A 0.14 N/A
Non-road Mobile............................. 0.02 N/A N/A 0.02 N/A
-------------------------------------------------------------------
Total................................... 36,441.93 56,198.55 46,549.50 22,269.90 32,736.76
----------------------------------------------------------------------------------------------------------------
Table 3-2--AEP Pirkey Power Plant SO2 EI Annual and Permitted Emissions in TPY \45\
----------------------------------------------------------------------------------------------------------------
2022
2017 2017 2017 Attainment Permitted
Source Reported Reported Reported year emissions
emissions emissions emissions emissions
----------------------------------------------------------------------------------------------------------------
Point--AEP Pirkey......................... 3,959.80 5,084.80 3,073.00 4,039.20 35,820.00
----------------------------------------------------------------------------------------------------------------
The EPA agrees that the State's emissions inventories for point,
nonpoint, and mobile sources are appropriate because they have been
accumulated and reported in accordance with established methods and
criteria. EPA proposes that the base year emissions inventory is
representative and satisfies the EI requirement, however, EPA cannot
fully approve the future year emission inventory due to enforceability
concerns arising from the force majeure provision included in the
Agreed Order.
B. Reasonably Available Control Measures and Reasonably Available
Control Technology (RACM/RACT)
Section 172(c)(1) of the CAA requires states to adopt and submit
all RACM, including RACT, as needed to attain the standards as
expeditiously as practicable. Section 172(c)(6) requires the SIP to
contain enforceable emission limits and control measures necessary to
provide for timely attainment of the standard. The plan relies on
ambient SO<INF>2</INF> concentration reductions achieved by
implementation of the Agreed Order's control requirements and emissions
limits at Martin Lake. Martin Lake plans to implement SO<INF>2</INF>
emission limits (lb/hr and lb/MMBtu) for the three EGF boilers.
The control strategy at Martin Lake incorporates pre-combustion and
post- combustion controls for the three EGF boilers and sets
SO<INF>2</INF> emission limits for the two auxiliary boilers. The EGF
boilers will be limited to burning subbituminous coal, No. 2 fuel oil,
and natural gas during operations and additionally have a combined cap
on their firing rate (MMBtu/hr). Martin Lake intends for the
subbituminous coal to be the primary fuel burned, which is lower in
sulfur content compared to the lignite and lignite-blended mix of coals
historically used by the facility. TCEQ
[[Page 63131]]
additionally provides that the existing SO<INF>2</INF> wet limestone
scrubber system for the EGF boilers will be optimized to increase
efficiency to meet the limits in the Agreed Order.
The final emission limitations as included in the February 14,
2022, Agreed Order are provided earlier in this document in section
V.E., Emission Limitations. Texas has provided modeling which
demonstrates that these measures for Martin Lake provide for timely
attainment and meet the RACM and RACT requirements, without accounting
for excused emissions not in compliance with the limits during force
majeure periods. The EPA proposes that, but for the presence of the
force majeure provision, the state would satisfy the requirements in
section 172(c)(1) to adopt and submit all RACM, including RACT, as
needed to attain the standard as expeditiously as practicable and in
section 172(c)(6) to include emission limits as necessary to attain.
However, due to the presence of the force majeure provision, at this
time EPA can only propose a limited approval of the emission limits for
SIP strengthening purposes.
C. New Source Review (NSR)
In its submittal, TCEQ provided a certification statement that
Texas already has EPA-approved rules that address nonattainment NSR
requirements. EPA initially approved Texas' nonattainment NSR
regulations for SO<INF>2</INF> on November 27, 1995 (60 FR 49781). TCEQ
determined that because previously approved revisions to the Texas SIP
already includes 30 TAC section 116.12 (Nonattainment and Prevention of
Significant Deterioration Review Definitions) and 30 TAC section
116.151 (New Major Source or Major Modification in Nonattainment Area
Other Than Ozone), Texas has satisfied the nonattainment NSR SIP
requirements for the Rusk-Panola nonattainment area. Further, TCEQ
already certified that Texas has EPA-approved rules that cover
nonattainment NSR requirements with the timely-submitted 2010
SO<INF>2</INF> NAAQS Infrastructure and Transport SIP Revision.
Therefore, EPA concludes that the SIP satisfies the CAA's NSR
requirements.
D. Reasonable Further Progress (RFP)
Section 171(1) of the CAA defines RFP as ``such annual incremental
reductions in emissions of the relevant air pollutant as are required
by [part D] or may reasonably be required by the [EPA] for the purpose
of ensuring attainment of the applicable [NAAQS] by the applicable
attainment date.'' For purposes of SO<INF>2</INF>, the EPA issued
guidance prescribing how states could satisfy this requirement when
developing their nonattainment SIPs.\46\ Since pollutants like
SO<INF>2</INF> usually have a limited number of sources affecting areas
of air quality that are relatively well defined, and emissions control
measures for such sources generally provide significant and immediate
improvements in air quality, there is usually a single ``step'' between
pre-control nonattainment and post-control attainment. Therefore, due
to the discernible relationship between emissions and air quality, EPA
interprets RFP in the SO<INF>2</INF> context as ``adherence to an
ambitious compliance schedule'' which ``ensures that affected sources
implement appropriate control measures as expeditiously as
practicable'' to ensure attainment by the applicable attainment date.
See General Preamble, 74 FR 13498, 13547 (April l6, 1992).
---------------------------------------------------------------------------
\46\ See ``Guidance for 1-Hour SO<INF>2</INF> Nonattainment Area
SIP Submissions'', U.S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, April 23, 2014, which can be
accessed at: <a href="https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf">https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf</a>.
---------------------------------------------------------------------------
In its submittal, TCEQ provided its rationale for concluding that
the plan met the requirement for RFP in accordance with EPA guidance.
According to TCEQ, the Rusk-Panola area contains a single source with
well-defined emissions, such that emissions controls for this source
should result in a ``swift and dramatic improvement in air quality.''
TCEQ further explained that enforceable emission limitations would be
implemented for the source (Martin Lake) in this area and, therefore,
this compliance schedule fulfills the RFP requirement for the Rusk-
Panola area. In its submittal, TCEQ sets two compliance deadlines for
Vistra to meet its emissions limits from the Agreed Order. For limits
expressed in lbs/hr, compliance is required no later than the date by
which Texas is required to demonstrate compliance with the 2010
SO<INF>2</INF> NAAQS, which would be the area's attainment date of
January 12, 2022. For limits expressed in lbs/MMBtu, compliance is
required by July 11, 2022. EPA has determined that once control
requirements and emissions limits have been implemented, these measures
will provide for attainment in the area. This meets the requirement for
RFP for the Rusk-Panola area. EPA proposes a limited approval/limited
disapproval for this SIP submission in part because the compliance date
is several months after the attainment date for this area. EPA proposes
that, but for the presence of the force majeure provision, the SIP
submittal would provide for RFP. However, due to the force majeure
provision and untimely compliance date, EPA proposes a limited approval
and limited disapproval of the SIP limits Texas relied upon for its RFP
demonstration for SIP strengthening purposes and to apply federally
enforceable limits to the area as expeditiously as possible.
E. Contingency Measures
As discussed in our 2014 SO<INF>2</INF> Guidance, section 172(c)(9)
of the CAA defines contingency measures as such measures in a SIP that
are to be implemented in the event that an area fails to make RFP, or
fails to attain the NAAQS, by the applicable attainment date.
Contingency measures are to become effective without further action by
the state or the EPA, where the area has failed to (1) achieve RFP or
(2) attain the NAAQS by the statutory attainment date for the affected
area. These control measures are to consist of other available control
measures that are not included in the control strategy for the
nonattainment area SIP. EPA guidance describes special features of
SO<INF>2</INF> planning that influence the suitability of alternative
means of addressing the requirement in section 172(c)(9) for
contingency measures. Because SO<INF>2</INF> control measures are by
definition based on what is directly and quantifiably necessary for
emissions controls, any violations of the NAAQS are likely related to
source violations of a source's permit or agreed order terms.
Therefore, an appropriate means of satisfying this requirement for
SO<INF>2</INF> is for the state to have a comprehensive enforcement
program that identifies sources of violations of the SO<INF>2</INF>
NAAQS and to undertake an aggressive follow-up for compliance and
enforcement.
For its contingency plan, Texas stated that TCEQ's comprehensive
program to (1) identify sources of violations of the NAAQS is satisfied
through its monitoring network and (2) follow-up for compliance and
enforcement is satisfied through TCEQ's enforcement programs authorized
under the Texas Water Code and Texas Health and Safety Code. If EPA
makes the determination that that the Rusk-Panola Area has failed to
attain, TCEQ will notify Martin Lake and upon notification the owner or
operator will be required to do a full system audit of all
SO<INF>2</INF> emissions from Martin Lake within 90 days. The owner or
operator of Martin Lake must conduct a root cause analysis for the
reason why the area failed to attain and recommend provisional
SO<INF>2</INF> emission controls as
[[Page 63132]]
necessary. Additionally, Texas has the authority to issue orders
pursuant to the Texas Clean Air Act and Texas Health and Safety Code
for the purpose of supporting attainment and maintenance of the 2010
SO<INF>2</INF> NAAQS. EPA believes that this approach generally
continues to be a valid approach for the implementation of contingency
measures to address the 2010 SO<INF>2</INF> NAAQS. However, as
previously discussed, the presence of the force majeure provision
undermines the enforceability of the emission limits in the SIP
submission, and consequently undermines the utility of Texas'
enforcement authority to address periods of non-compliance with the
limits. Therefore, EPA is proposing that but for the presence of the
force majeure provision, Texas' plan would adequately provide for
contingency measures as required by the CAA. As a result, EPA can only
propose limited approval of the limits upon which the SIP relies for
SIP strengthening purposes.
F. Conformity
Generally, as set forth in section 176(c) of the CAA, conformity
requires that actions by federal agencies do not cause new air quality
violations, worsen existing violations, or delay timely attainment of
the relevant NAAQS. General conformity applies to federal actions,
other than certain highway and transportation projects, if the action
takes place in a nonattainment area or maintenance area (i.e., an area
which submitted a maintenance plan that meets the requirements of
section 175A of the CAA and has been redesignated to attainment) for
ozone, particulate matter, nitrogen dioxide, carbon monoxide, lead, or
SO<INF>2.</INF> EPA's General Conformity Rule (40 CFR 93.150 to 93.165)
establishes the criteria and procedures for determining if a federal
action conforms to the SIP. With respect to the 2010 SO<INF>2</INF>
NAAQS, federal agencies are expected to continue to estimate emissions
for conformity analyses in the same manner as they estimated emissions
for conformity analyses under the previous SO<INF>2</INF> NAAQS. EPA's
General Conformity Rule includes the basic requirement that a federal
agency's general conformity analysis be based on the latest and most
accurate emission estimation techniques available (40 CFR 93.159(b)).
When updated and improved emissions estimation techniques become
available, EPA expects the federal agency to use these techniques. EPA
finds that the Rusk-Panola SO<INF>2</INF> Attainment Plan SIP Revision
submission meets these conformity requirements.
Transportation conformity determinations are not required in
SO<INF>2</INF> nonattainment and maintenance areas. EPA concluded in
its 1993 transportation conformity rule that highway and transit
vehicles are not significant sources of SO<INF>2</INF>. Therefore,
transportation plans, transportation improvement programs and projects
are presumed to conform to applicable implementation plans for
SO<INF>2</INF>. (See 58 FR 3776, January 11, 1993.)
VII. Proposed Action
For Texas' February 28, 2022 SIP revision submittal, we are
proposing a limited approval which will incorporate all of the
submissions requirements, including the emission limits and associated
control requirements such as monitoring, recordkeeping and reporting
requirements into the State Implementation Plan. We have determined
that the revision provides for emissions controls and limits that
strengthen the existing EPA-approved Texas SIP and would satisfy the
applicable CAA requirements of sections 110, 172, 191 and 192. We are
proposing limited disapproval due to the enforceability deficiency
caused by the force majeure provision in the SIP and the timing of the
compliance date for the emissions limitations several months after the
attainment date for this nonattainment area, as is necessary under the
CAA and associated regulations. The State has demonstrated that its
current Nonattainment NSR program covers this NAAQS; therefore, no
revision to the SIP is required for the Nonattainment NSR element.
Under CAA section 179(c)(1), EPA also proposes to determine that the
Rusk-Panola SO<INF>2</INF> NAA failed to attain the 2010 1-hour
SO<INF>2</INF> standard by the applicable attainment date of January
12, 2022 based on monitored data from 2019-2021.
VIII. Incorporation by Reference
In this action, we are proposing to include in a final rule
regulatory text that includes incorporation by reference. In accordance
with the requirements of 1 CFR 51.5, we are proposing to incorporate by
reference revisions to the Texas source-specific requirements for
Vistra's Martin Lake Electrical Station (Martin Lake) as described in
section VII of this preamble, Proposed Action. These source-specific
requirements for Martin Lake include SO<INF>2</INF> emission limits and
fuel limitations for the facility as well as other monitoring,
recordkeeping, and reporting requirements. We have made, and will
continue to make, these documents generally available electronically
through <a href="http://www.regulations.gov">www.regulations.gov</a> (please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section of this preamble for more
information).
IX. Environmental Justice Considerations
Information on Executive Order 12898 (Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations, 59 FR 7629, February 16, 1994), and how EPA defines
environmental justice (EJ) can be found in the section titled ``VII.
Statutory and Executive Order Reviews,'' in this proposed rulemaking.
EPA is providing additional analysis of environmental justice
associated with this action. The results of this analysis are being
provided for informational and transparency purposes only, not as a
basis of our proposed action.
The EPA conducted a screening analysis using EJSCREEN, an
environmental justice mapping and screening tool that provides EPA with
a nationally consistent dataset and approach for combining various
environmental and demographic indicators.\47\ The EJSCREEN tool
presents these indicators at a Census block group (CBG) level or a
larger user-specified ``buffer'' area that covers multiple CBGs.\48\ An
individual CBG is a cluster of contiguous blocks within the same census
tract and generally contains between 600 and 3,000 people. EJSCREEN is
not a tool for performing in-depth risk analysis, but is instead a
screening tool that provides an initial representation of indicators
related to environmental justice and is subject to uncertainty in some
underlying data (e.g., some environmental indicators are based on
monitoring data which are not uniformly available; others are based on
self-reported data).\49\ To help mitigate this uncertainty, we have
summarized EJSCREEN data within larger ``buffer'' areas covering
multiple block groups and representing the average resident within the
buffer area surrounding Martin Lake. We present EJSCREEN environmental
indicators to help screen
[[Page 63133]]
for locations where residents may experience a higher overall pollution
burden than would be expected for a block group with the same total
population. These indicators of overall pollution burden include
estimates of ambient particulate matter (PM<INF>2.5</INF>) and ozone
concentration, a score for traffic proximity and volume, percentage of
pre-1960 housing units (lead paint indicator), and scores for proximity
to Superfund sites, risk management plan (RMP) sites, and hazardous
waste facilities.\50\ EJSCREEN also provides information on demographic
indicators, including percent low-income, communities of color,
linguistic isolation, and less than high school education.
---------------------------------------------------------------------------
\47\ The EJSCREEN tool is available at <a href="https://www.epa.gov/ejscreen">https://www.epa.gov/ejscreen</a>.
\48\ See <a href="https://www.census.gov/programs-surveys/geography/about/glossary.html">https://www.census.gov/programs-surveys/geography/about/glossary.html</a>.
\49\ In addition, EJSCREEN relies on the five-year block group
estimates from the U.S. Census American Community Survey. The
advantage of using five-year over single-year estimates is increased
statistical reliability of the data (i.e., lower sampling error),
particularly for small geographic areas and population groups. For
more information, see <a href="https://www.census.gov/content/dam/Census/library/publications/2020/acs/acs_general_handbook_2020.pdf">https://www.census.gov/content/dam/Census/library/publications/2020/acs/acs_general_handbook_2020.pdf</a>.
\50\ For additional information on environmental indicators and
proximity scores in EJSCREEN, see ``EJSCREEN Environmental Justice
Mapping and Screening Tool: EJSCREEN Technical Documentation for
Version 2.2,'' Chapter 3 (July 2023) at <a href="https://www.epa.gov/system/files/documents/2023-06/ejscreen-tech-doc-version-2-2.pdf">https://www.epa.gov/system/files/documents/2023-06/ejscreen-tech-doc-version-2-2.pdf</a>.
---------------------------------------------------------------------------
The EPA prepared an EJSCREEN report covering a buffer area of
approximately a 6-mile radius around the Martin Lake facility. Table 4
presents a summary of results from the EPA's screening-level analysis
for Martin Lake compared to the U.S. as a whole. From that report,
Martin Lake did not show EJ indices greater than the 80th percentiles.
The full, detailed EJSCREEN report is provided in the docket for this
rulemaking.
Table 4--EJSCREEN Analysis Summary for Martin Lake
------------------------------------------------------------------------
EJSCREEN values for buffer area (radius)
for Martin Lake and the U.S. (percentile
within U.S. where indicated)
Variables ------------------------------------------
Martin Lake
(Rusk-Panola U.S.
Area, 6 miles)
------------------------------------------------------------------------
Pollution Burden Indicators:
Particulate matter 9.57 [micro]g/ 8.67 [micro]g/m\3\ (--).
(PM2.5), annual average. m\3\ (77th
%ile).
Ozone, summer seasonal 40.1 ppb (32nd 42.5 ppb (--).
average of daily 8-hour max. %ile).
Traffic proximity and 0.72 (2nd %ile) 760 (--).
volume score *.
Lead paint (percentage 0.12% (37th 0.27% (--).
pre-1960 housing). %ile).
Superfund proximity score 0.048 (42nd 0.13 (--).
*. %ile).
RMP proximity score *.... 0.17 (32nd 0.77 (--).
%ile).
Hazardous waste proximity 0.059 (11th 2.2 (--).
score *. %ile).
Demographic Indicators:
People of color 31% (52nd %ile) 40% (--).
population.
Low-income population.... 25% (46th %ile) 30% (--).
Linguistically isolated 2% (62nd %ile). 5% (--).
population.
Population with less than 13% (65th %ile) 12% (--).
high school education.
Population under 5 years 9% (82nd %ile). 6%.
of age.
Population over 64 years 14% (44th %ile) 16% (--).
of age.
------------------------------------------------------------------------
* The traffic proximity and volume indicator is a score calculated by
daily traffic count divided by distance in meters to the road. The
Superfund proximity, RMP proximity, and hazardous waste proximity
indicators are all scores calculated by site or facility counts
divided by distance in kilometers.
This proposed action is proposing limited approval and limited
disapproval of Texas' February 28, 2022, SIP submittal to strengthen
the SIP requirements for the Rusk-Panola NAA for the 2010 1-hour
primary SO<INF>2</INF> NAAQS. Information on SO<INF>2</INF> and its
relationship to negative health impacts can be found at final Federal
Register notice titled ``Primary National Ambient Air Quality Standard
for Sulfur Dioxide'' (75 FR 35520, June 22, 2010).\51\ We expect that
this action and resulting emissions reductions will generally be
neutral or contribute to reduced environmental and health impacts on
all populations in the Rusk-Panola NAA, including people of color and
low-income populations in the Rusk-Panola nonattainment area. At a
minimum, this action would not worsen any existing air quality and is
expected to help the area make progress towards meeting requirements to
attain air quality standards. Further, there is no information in the
record indicating that this action is expected to have
disproportionately high or adverse human health or environmental
effects on a particular group of people.
---------------------------------------------------------------------------
\51\ See <a href="https://www.federalregister.gov/d/2010-13947">https://www.federalregister.gov/d/2010-13947</a>.
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X. Statutory and Executive Order Reviews
Under the Clean Air Act, the Administrator is required to approve a
SIP submission that complies with the provisions of the Clean Air Act
and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions, EPA's role is to approve state
choices, provided that they meet the criteria of the Clean Air Act.
Accordingly, this proposed action is proposing a limited approval and
limited disapproval of state law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by state
law. For that reason, this action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Orders 12866 (58
FR 51735, October 4, 1993) and 14094 (88 FR 21879, April 11, 2023);
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
[[Page 63134]]
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the Clean Air Act.
<bullet> Executive Order 12898 (Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations, 59 FR 7629, February 16, 1994) directs Federal agencies to
identify and address ``disproportionately high and adverse human health
or environmental effects'' of their actions on minority populations and
low-income populations to the greatest extent practicable and permitted
by law. EPA defines environmental justice (EJ) as ``the fair treatment
and meaningful involvement of all people regardless of race, color,
national origin, or income with respect to the development,
implementation, and enforcement of environmental laws, regulations, and
policies.'' EPA further defines the term fair treatment to mean that
``no group of people should bear a disproportionate burden of
environmental harms and risks, including those resulting from the
negative environmental consequences of industrial, governmental, and
commercial operations or programs and policies.''
TCEQ did not evaluate environmental justice considerations as part
of its SIP submittal; the CAA and applicable implementing regulations
neither prohibit nor require such an evaluation. EPA performed an
environmental justice analysis, as is described above in the section
titled, ``Environmental Justice Considerations.'' The analysis was done
for the purpose of providing additional context and information about
this rulemaking to the public, not as a basis of the action. Due to the
nature of the action being taken here, this action is expected to have
a neutral to positive impact on the air quality of the affected area.
In addition, there is no information in the record upon which this
decision is based inconsistent with the stated goal of E.O. 12898 of
achieving environmental justice for people of color, low-income
populations, and Indigenous peoples.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the proposed rule does not have tribal implications and will
not impose substantial direct costs on tribal governments or preempt
tribal law as specified by Executive Order 13175 (65 FR 67249, November
9, 2000).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Reporting and recordkeeping
requirements, Sulfur oxides.
Authority: 42 U.S.C. 7401 et seq.
Dated: July 29, 2024.
Earthea Nance,
Regional Administrator, Region 6.
[FR Doc. 2024-17053 Filed 8-1-24; 8:45 am]
BILLING CODE 6560-50-P
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on August 2, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.