[Federal Register Volume 89, Number 70 (Wednesday, April 10, 2024)]
[Proposed Rules]
[Pages 25200-25216]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-07414]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2022-0536; FRL-11829-01-R8]


Air Plan Approval; Wyoming; Revisions to Regional Haze State 
Implementation Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a State Implementation Plan (SIP) revision submitted by the 
State of Wyoming on December 30, 2022, and supplemented on August 31, 
2023, and November 16, 2023, addressing regional haze (Wyoming 2022 SIP 
revision). The Wyoming 2022 SIP revision replaces Wyoming's previously 
approved source-specific nitrogen oxide (NOX) determination 
for PacifiCorp's Jim Bridger power plant (Jim Bridger) Units 1 and 2 of 
0.07 lb/MMBtu for each unit associated with the installation of 
selective catalytic reduction (SCR) controls to address the long-term 
strategy. Specifically, the Wyoming 2022 SIP revision finds that 
conversion from coal-firing to natural gas-firing, together with 
NOX emission and heat input limits of 0.12 lb/MMBtu (30-day 
rolling average), 1,314 tons/year, and 21,900,000 MMBtu/year, 
respectively, allows for identical reasonable progress during the first 
planning period as the installation SCR controls. Separately, we are 
also proposing to approve Wyoming's monthly and annual NOX 
and sulfur dioxide (SO2) emissions limits for Jim Bridger 
Units 1-4. The EPA is proposing this action pursuant to sections 110 
and 169A of the Clean Air Act (CAA).

DATES: Comments: Written comments must be received on or before May 10, 
2024.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2022-0536, to the Federal Rulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
https://www.regulations.gov. 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, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    Docket: All documents in the docket are listed in the https://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available electronically in 
https://www.regulations.gov. Please email or call the person listed in 
the FOR FURTHER INFORMATION CONTACT section if you need to make 
alternative arrangements for access to the docket.

FOR FURTHER INFORMATION CONTACT: Jaslyn Dobrahner, Air and Radiation 
Division, EPA, Region 8, Mailcode 8P-ARD, 1595 Wynkoop Street, Denver, 
Colorado 80202-1129, telephone number: (303) 312-6252, email address: 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA.

I. What action is the EPA proposing?
II. Background
    A. Requirements of the Clean Air Act and the EPA's Regional Haze 
Rule
    B. Best Available Retrofit Technology (BART)
    C. Long-Term Strategy and Reasonable Progress Requirements
    D. Consultation With Federal Land Managers (FLMs)
    E. Monitoring, Recordkeeping, and Reporting
III. Wyoming's Regional Haze SIP Submittals
    A. Background and Wyoming's Initial Regional Haze SIP
    B. November 2017 Regional Haze Progress Report
    C. May 2020 Regional Haze SIP Revision
    D. December 2022 Regional Haze SIP Revision
    E. Wyoming's Reassessment of Reasonable Progress Under Long-Term 
Strategy
    1. Costs of Compliance
    2. Time Necessary for Compliance
    3. Energy and Non-Air Quality Environmental Impacts of 
Compliance
    4. Remaining Useful Life
    5. Reasonable Progress Demonstration
    F. Summary of Wyoming's Additional Proposed Revisions to the 
Emission Limits for Jim Bridger
IV. The EPA's Evaluation and Proposed Approval of Wyoming's Regional 
Haze SIP Revisions
    A. The EPA's Proposed Approval of Wyoming's Reasonable Progress 
Determination for Jim Bridger Units 1 and 2
    1. Basis for the EPA's Proposed Approval
    a. Costs of Compliance
    b. Other Statutory Factors
    c. Analysis of Projected Emissions Reductions Achievable
    2. Summary of the EPA's Evaluation of Wyoming's Reasonable 
Progress Demonstration
    B. The EPA's Proposed Approval of Wyoming's Long-Term Strategy 
for Jim Bridger Units 1 and 2
    C. Monthly and Annual NOX and SO2 Emission 
Limits for Jim Bridger Units 1-4
    D. Monitoring, Recordkeeping, and Reporting
    E. Consultation With Federal Land Managers
V. Clean Air Act Section 110(l)
VI. Summary of the EPA's Proposed Action
VII. Incorporation by Reference
VIII. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

    The Jim Bridger power plant is located in Sweetwater County, 
Wyoming, and is owned in part, and operated, by PacifiCorp. The power 
plant is composed of four 530 megawatt (MW) tangentially fired boilers 
burning pulverized coal for a total net generating capacity of 2,120 
MW.
    On January 30, 2014, the EPA promulgated a final rule titled, 
``Approval, Disapproval and Promulgation of Implementation Plans; State 
of Wyoming; Regional Haze State Implementation Plan; Federal 
Implementation Plan for Regional Haze,'' approving, in part, a regional 
haze SIP revision submitted by the State of Wyoming on January 12, 2011 
(2014 final rule).\1\ In the 2014 final rule, the EPA approved 
Wyoming's determination to require low-NOX burners (LNB) and 
separated overfire air (SOFA) at Jim Bridger Units 1-4, with

[[Page 25201]]

a NOX best available retrofit technology (BART) emission 
limit of 0.26 pounds per million British Thermal Units (lb/MMBtu) (30-
day rolling average) for Jim Bridger Units 1-4.\2\ The EPA also 
approved Wyoming's determination to require SCR at Jim Bridger Units 1-
4, with a NOX emission limit of 0.07 lb/MMBtu (30-day 
rolling average), as part of its long-term strategy.\3\
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    \1\ 79 FR 5032 (January 30, 2014).
    \2\ Wyoming determined that all four units are subject to BART. 
77 FR 33022, 33030, 33035 (June 4, 2012).
    \3\ The BART determination compliance date for all units was 
March 4, 2019. Long-term strategy determination compliance dates for 
each include: Unit 1 = December 31, 2022; Unit 2 = December 31, 
2021; Unit 3 = December 31, 2015; and Unit 4 = December 31, 2016.
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    The EPA is proposing to approve a SIP revision submitted by the 
State to the EPA on December 30, 2022, and supplemented on August 31, 
2023, and November 16, 2023, which will replace the previously approved 
NOX emission limit of 0.07 lb/MMBtu (30-day rolling average) 
at Jim Bridger Units 1 and 2 for Wyoming's long-term strategy.\4\ The 
Wyoming 2022 SIP revision amends the State's previously approved long-
term strategy for the first Regional Haze planning period and is 
requiring Jim Bridger Units 1 and 2 to operate consistent with 
conversion from coal-firing to natural gas-firing by January 1, 2024, 
with NOX emission limits of 0.12 lb/MMBtu (30-day rolling 
average) and 1,314 tons/year for each unit and a heat input limit of 
21,900,000 MMBtu/year per unit. The Wyoming 2022 SIP revision reflects 
changes to Chapters 7 and 8 of Wyoming's regional haze SIP narrative 
\5\ and incorporates certain conditions of Wyoming air quality permits 
#P0025809 and #P0036941, some conditions of which were memorialized in 
a Wyoming court-approved consent decree between Wyoming and 
PacifiCorp.6 7 Ultimately, the Wyoming 2022 SIP revision 
finds conversion from coal-firing to natural gas-firing, together with 
NOX emission and heat input limits, to be sufficient for 
reasonable progress during the first planning period, and finds the 
emission limits associated with the installation of SCR controls are no 
longer required. The State also included NOX and 
SO2 monthly and annual emissions limits for Jim Bridger 
Units 1-4.\8\
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    \4\ On May 23, 2022, Wyoming submitted a draft SIP revision and 
requested that the EPA parallel process this revision to their 
Regional Haze 309(g) first planning period SIP. Parallel processing 
generally refers to concurrent state and federal proposed rulemaking 
actions. In this action, however, the state submitted a final SIP 
revision after the state concluded its state rulemaking action thus 
we are proposing action on the state's final SIP revision and are 
not parallel processing the rulemaking.
    \5\ State of Wyoming, ``Addressing Regional Haze Visibility 
Protection For The Mandatory Federal Class I Areas Required Under 40 
CFR 51.309,'' Revised May 23, 2022 (``Wyoming 2022 SIP revision'').
    \6\ Consent Decree, State of Wyoming v. PacifiCorp, Docket No. 
2022-CV-200-333, First Judicial District Court, Laramie, Wyoming. 
(February 14, 2022).
    \7\ An EPA Administrative Compliance Order On Consent found 
PacifiCorp in violation of the Wyoming SIP and the Clean Air Act and 
ordered PacifiCorp to comply, no later than June 9, 2023, with the 
terms of the Wyoming 2022 SIP revision, based on the requirements 
found in the February 14, 2022 consent decree. EPA Administrative 
Compliance Order On Consent, PacifiCorp--Jim Bridger Power Plant, 
CAA-08-2022-0006 (EPA June 9, 2022).
    \8\ These limits represent a separate SIP component from 
Wyoming's long-term strategy analysis and determination. See 
sections IV.C. and VI.
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II. Background

A. Requirements of the Clean Air Act and the EPA's Regional Haze Rule

    In section 169A of the CAA, Congress created a program for 
protecting visibility in national parks and wilderness areas. This 
section of the CAA establishes ``as a national goal the prevention of 
any future, and the remedying of any existing, impairment of visibility 
in mandatory Class I Federal areas which impairment results from 
manmade air pollution.'' \9\
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    \9\ 42 U.S.C. 7491(a). Areas designated as mandatory Class I 
Federal areas consist of national parks exceeding 6,000 acres, 
wilderness areas and national memorial parks exceeding 5,000 acres, 
and all international parks that were in existence on August 7, 
1977. 42 U.S.C. 7472(a). In accordance with section 169A of the CAA, 
the EPA, in consultation with the Department of Interior, 
promulgated a list of 156 areas where visibility is identified as an 
important value. 44 FR 69122 (November 30, 1979). The extent of a 
mandatory Class I area includes subsequent changes in boundaries, 
such as park expansions. 42 U.S.C. 7472(a). Although states and 
tribes may designate as Class I additional areas whose visibility 
they consider to be an important value, the requirements of the 
visibility program set forth in section 169A of the CAA apply only 
to ``mandatory Class I Federal areas.'' Each mandatory Class I 
Federal area is the responsibility of a ``Federal Land Manager.'' 42 
U.S.C. 7602(i). When we use the term ``Class I area'' in this 
action, we mean a ``mandatory Class I Federal area.''
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    The EPA promulgated a rule to address regional haze on July 1, 
1999.\10\ The Regional Haze Rule revised the existing visibility 
regulations \11\ to integrate provisions addressing regional haze and 
established a comprehensive visibility protection program for Class I 
areas. The requirements for regional haze, found at 40 CFR 51.308 and 
40 CFR 51.309, are included in the EPA's visibility protection 
regulations at 40 CFR 51.300 through 40 CFR 51.309.\12\
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    \10\ 64 FR 35714, 35714 (July 1, 1999) (codified at 40 CFR part 
51, subpart P).
    \11\ The EPA had previously promulgated regulations to address 
visibility impairment in Class I areas that is ``reasonably 
attributable'' to a single source or small group of sources, i.e., 
reasonably attributable visibility impairment (RAVI). 45 FR 80084, 
80084 (December 2, 1980).
    \12\ The EPA revised the Regional Haze Rule on January 10, 2017. 
82 FR 3078 (January 10, 2017). Under the revised Regional Haze Rule, 
the requirements 40 CFR 51.308(d) and (e) apply to first 
implementation period SIP submissions and 51.308(f) applies to 
submissions for the second and subsequent implementation periods. 82 
FR 3087; see also 81 FR 26942, 26952 (May 4, 2016).
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    The CAA requires each state to develop a SIP to meet various air 
quality requirements, including protection of visibility.\13\ Regional 
haze SIPs must assure reasonable progress toward the national goal of 
preventing future and remedying existing manmade visibility impairment 
in Class I areas. A state must submit its SIP and SIP revisions to the 
EPA for approval.\14\ Once approved, a SIP is enforceable by the EPA 
and citizens under the CAA; that is, the SIP is federally enforceable.
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    \13\ 42 U.S.C. 7410(a), 7491, and 7492(a); CAA sections 110(a), 
169A, and 169B.
    \14\ 42 U.S.C. 7491(b)(2); 7410.
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B. Best Available Retrofit Technology (BART)

    Section 169A(b)(2) of the CAA requires SIPs to contain such 
measures as may be necessary to make reasonable progress toward meeting 
the national visibility goal. Section 169(b)(2)(A) specifies that one 
such requirement for the first regional haze planning period is for 
certain categories of existing major stationary sources built between 
1962 and 1977 to procure, install, and operate BART as determined by 
the states through their SIPs. Under the Regional Haze Rule, states (or 
the EPA, in the promulgation of a federal implementation plan (FIP)) 
are directed to conduct BART determinations for ``BART-eligible'' 
sources--typically larger, often uncontrolled, and older stationary 
sources--that may reasonably be anticipated to cause or contribute to 
any visibility impairment in a Class I area.\15\ States must consider 
the following five factors in making BART determinations: (1) the costs 
of compliance; (2) the energy and non-air quality environmental impacts 
of compliance; (3) any existing pollution control technology in use at 
the source; (4) the remaining useful life of the source; and (5) the 
degree of improvement of visibility which may reasonably be anticipated 
to result from

[[Page 25202]]

the use of such technology.\16\ Rather than requiring source-specific 
BART controls, states also have the flexibility to adopt an emissions 
trading program or other alternative program as long as the alternative 
will achieve greater reasonable progress toward natural visibility 
conditions than BART.\17\
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    \15\ 40 CFR 51.308(e). The EPA designed the Guidelines for BART 
Determinations Under the Regional Haze Rule (Guidelines) 40 CFR 
appendix Y to part 51 ``to help States and others (1) identify those 
sources that must comply with the BART requirement, and (2) 
determine the level of control technology that represents BART for 
each source.'' Guidelines, section I.A. section II. of the 
Guidelines describes the four steps to identify BART sources, and 
section III. explains how to identify BART sources (i.e., sources 
that are ``subject to BART'').
    \16\ 40 CFR 51.308(e)(1)(ii).
    \17\ 40 CFR 51.308(e)(2). WildEarth Guardians v. EPA, 770 F.3d 
919, 934 (10th Cir. 2014).
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    One such BART alternative is included in 40 CFR 51.309 and is an 
option for nine states termed the ``Transport Region States,'' which 
include Arizona, California, Colorado, Idaho, Nevada, New Mexico, 
Oregon, Utah, and Wyoming. Transport Region States can adopt regional 
haze strategies based on recommendations from the Grand Canyon 
Visibility Transport Commission (GCVTC) for protecting the 16 Class I 
areas on the Colorado Plateau.\18\
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    \18\ The Colorado Plateau is a high, semi-arid area in southeast 
Utah, northern Arizona, northwest New Mexico, and western Colorado. 
The 16 mandatory Class I areas are Grand Canyon National Park, Mount 
Baldy Wilderness, Petrified Forest National Park, Sycamore Canyon 
Wilderness, Black Canyon of the Gunnison National Park Wilderness, 
Flat Tops Wilderness, Maroon Bells Wilderness, Mesa Verde National 
Park, Weminuche Wilderness, West Elk Wilderness, San Pedro Park 
Wilderness, Arches National Park, Bryce Canyon National Park, 
Canyonlands National Park, Capital Reef National Park, and Zion 
National Park.
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    As part of its overall plan for making reasonable progress towards 
the national visibility goal for the 16 Class I areas, the GCVTC 
submitted an annex to the EPA, known as the Western SO2 
Backstop Trading Program, containing annual SO2 emissions 
reduction milestones and detailed provisions of a backstop trading 
program to be implemented automatically if measures fail to achieve the 
SO2 milestones. The EPA approved the Backstop Trading 
Program as a BART alternative for SO2 emissions.\19\ 
Transport Region States' SIPs must also contain any necessary long-term 
strategy and BART requirements for stationary-source particulate matter 
(PM) and NOX emissions.\20\
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    \19\ 64 FR 35714 (July 1, 1999); 68 FR 33764 (June 5, 2003).
    \20\ 40 CFR 51.309(d)(4)(vii).
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C. Long-Term Strategy and Reasonable Progress Requirements

    In addition to the BART requirements, the CAA's visibility 
protection provisions also require that states' regional haze SIPs 
contain a ``long-term (ten to fifteen years) strategy for making 
reasonable progress toward meeting the national goal. . . .'' \21\ The 
long-term strategy must address regional haze visibility impairment for 
each mandatory Class I area within the state and for each mandatory 
Class I area located outside the state that may be affected by 
emissions from the state. It must include the enforceable emission 
limitations, compliance schedules, and other measures necessary to 
achieve the reasonable progress goals.\22\ The reasonable progress 
goals are calculated for each Class I area based on the control 
measures states have selected by analyzing the four statutory 
``reasonable progress'' factors, which are: ``the costs of compliance, 
the time necessary for compliance, the energy and non-air quality 
environmental impacts of compliance, and the remaining useful life of 
any existing source subject to such requirement.'' \23\ Thus, the four 
reasonable progress factors are considered by a state in setting the 
reasonable progress goal for the first planning period pursuant to 
Sec.  51.308(d)(1)(i)(A), by virtue of the state having first 
considered them, and certain other factors listed in Sec.  51.308(d)(3) 
of the Regional Haze Rule, when deciding what controls are to be 
included in the long-term strategy. Then, the numerical levels of the 
reasonable progress goals are the predicted visibility outcome of 
implementing the long-term strategy in addition to ongoing pollution 
control programs stemming from other CAA requirements.
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    \21\ 42 U.S.C. 7491(b)(2)(B).
    \22\ 40 CFR 51.308(d)(3).
    \23\ 42 U.S.C. 7491(g)(1); 40 CFR 51.308(d)(1)(i).
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    Unlike BART determinations, which are required only for the first 
regional haze planning period SIPs,\24\ states are required to submit 
updates to their long-term strategies, including updated reasonable 
progress analyses and reasonable progress goals, in the form of SIP 
revisions by July 31, 2021, and at specific intervals thereafter.\25\ 
In addition, each state must periodically submit a report to the EPA at 
five-year intervals beginning five years after the submission of the 
initial regional haze SIP, evaluating the state's progress towards 
meeting the reasonable progress goals for each Class I area within the 
state.\26\
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    \24\ Under the Regional Haze Rule, SIPs are due for each 
regional haze planning or implementation period. The terms 
``planning period'' and ``implementation period'' are used 
interchangeably in this document.
    \25\ 40 CFR 51.308(f). The deadline for the 2018 SIP revision 
was moved to 2021. 82 FR 3078 (January 10, 2017); see also 40 CFR 
51.308(f). Following the 2021 SIP revision deadline, the next SIP 
revision is due in 2028. 40 CFR 51.308(f).
    \26\ Id. Sec.  51.308(g); 51.309(d)(10).
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    By meeting all the requirements of 40 CFR 51.309, including the 
section 309-specific BART requirements, a Transport Region State can be 
deemed to be making reasonable progress toward the national goal for 
the 16 Class I areas on the Colorado Plateau.\27\ For stationary 
sources, these requirements include any necessary long-term strategies 
for PM and NOX emissions.\28\ Additionally, the State of 
Wyoming includes several non-Colorado Plateau Class I areas, and was 
also required to submit a long-term strategy for those Class I 
areas.\29\ Wyoming's 2022 SIP revision addresses emissions reductions 
approved under its long-term strategy for the first implementation 
period. As a result, the time period relevant to this rulemaking is the 
first implementation period.
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    \27\ 40 CFR 51.309(a).
    \28\ 40 CFR 51.309(d)(4)(vii).
    \29\ 79 FR 5199 (March 3, 2014).
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D. Consultation With Federal Land Managers (FLMs)

    The Regional Haze Rule requires that a state consult with Federal 
Land Managers before adopting and submitting a required SIP or SIP 
revision. Further, when considering a SIP revision, a state must 
include in its proposal a description of how it addressed any comments 
provided by the FLMs.\30\
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    \30\ 40 CFR 51.308(i); CAA 169A(d).
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E. Monitoring, Recordkeeping, and Reporting

    The CAA requires that SIPs, including regional haze SIPs, contain 
elements sufficient to ensure emission limits are practically 
enforceable. CAA section 110(a)(2) states that the monitoring, 
recordkeeping, and reporting provisions of states' SIPs must: ``(A) 
include enforceable emissions limitations and other control measures, 
means, or techniques (including economic incentives such as fees, 
marketable permits, and auctions of emissions rights), as well as 
schedules and timetables for compliance, as may be necessary or 
appropriate to meet the applicable requirements of this chapter; . . . 
(C) include a program to provide for the enforcement of the measures 
described in subparagraph (A), and regulation of the modification and 
construction of any stationary source within the areas covered by the 
plan as necessary to assure that national ambient air quality standards 
are achieved, including a permit program as required in parts C and D 
of this subchapter; . . . (F) require, as may be prescribed by the 
Administrator--(i) the installation, maintenance, and replacement of 
equipment, and the implementation of other necessary

[[Page 25203]]

steps, by owners or operators of stationary sources to monitor 
emissions from such sources, (ii) periodic reports on the nature and 
amounts of emissions and emissions-related data from such sources, and 
(iii) correlation of such reports by the State agency with any 
emissions limitations or standards established pursuant to this 
chapter, which reports shall be available at reasonable times for 
public inspection.'' \31\
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    \31\ 42 U.S.C. 7410(a)(2)(A), (C), and (F).
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    Accordingly, 40 CFR part 51, subpart K, Source Surveillance, 
requires the SIP to provide for monitoring the status of compliance 
with the regulations in the SIP, including ``[p]eriodic testing and 
inspection of stationary sources,'' \32\ and ``legally enforceable 
procedures'' for recordkeeping and reporting.\33\ Furthermore, 40 CFR 
part 51, appendix V, Criteria for Determining the Completeness of Plan 
Submissions, states in section 2.2 that complete SIPs contain: ``(g) 
Evidence that the plan contains emission limitations, work practice 
standards and recordkeeping/reporting requirements, where necessary, to 
ensure emission levels''; and ``(h) Compliance/enforcement strategies, 
including how compliance will be determined in practice.'' \34\
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    \32\ 40 CFR 51.212.
    \33\ Id. Sec.  51.214.
    \34\ 40 CFR part 51, appendix V.
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III. Wyoming's Regional Haze SIP Submittals

A. Background and Wyoming's Initial Regional Haze SIP

    On January 12, 2011, Wyoming submitted its first regional haze SIP 
pursuant to 40 CFR 51.309. The State determined that NOX 
BART for Jim Bridger Units 1-4 was new LNBs with SOFA at an emissions 
rate of 0.26 lb/MMBtu (30-day rolling average). Compliance with the 
BART emission limits was required by March 4, 2019, for all four Jim 
Bridger units.\35\ The State also determined that SCR at an emissions 
rate of 0.07 lb/MMBtu (30-day rolling average) should be installed at 
all four units as part of the State's long-term strategy to achieve 
reasonable progress at several Class I areas, and required compliance 
with the emission limits by December 31, 2022, December 31, 2021, 
December 31, 2015 and December 31, 2016, for Units 1-4, 
respectively.\36\
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    \35\ 79 FR 5221. Installation of new LNB with SOFA (LNB/SOFA) 
corresponds to a NOX emissions limit of 0.26 lb/MMBtu 
(30-day rolling average).
    \36\ Id. Installation of SCR corresponds to a NOX 
emissions limit of 0.07 lb/MMBtu (30-day rolling average).
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    On June 4, 2012, we proposed to approve the State's BART and 
reasonable progress determinations of 0.26 lb/MMBtu (30-day rolling 
average) and 0.07 lb/MMBtu (30-day rolling average), respectively, for 
Units 3 and 4, including the associated dates for compliance with these 
emissions limits.\37\ We subsequently finalized our proposed action for 
Units 3 and 4.\38\
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    \37\ Id. See also 40 CFR 51.308(e)(1)(iv).
    \38\ 79 FR 5046, 5221.
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    For Jim Bridger Units 1 and 2, we also proposed to approve the 
State's BART and reasonable progress determinations of 0.26 lb/MMBtu 
(30-day rolling average) and 0.07 lb/MMBtu (30-day rolling average), 
respectively. In the alternative, we proposed to find NOX 
BART for Jim Bridger Units 1 and 2 was an emissions limit of 0.07 lb/
MMBtu (30-day rolling average), consistent with the installation of 
LNB/SOFA + SCR, with a compliance deadline of five years.\39\ In our 
final rule, upon consideration of new information and a review of the 
State`s analysis of the BART factors, we found that the source-wide 
visibility improvement associated with the installation of LNB/SOFA + 
SCR to be 1.25-1.5 deciviews,\40\ while the unit-specific visibility 
benefits for Units 1 and 2 were 0.27-0.37 deciviews. We found that the 
average cost-effectiveness of LNB/SOFA + SCR at $2,635 and $3,403/ton 
of NOX for Units 1 and 2, respectively, was in line with 
what we had found to be acceptable in other BART determinations.\41\ 
But we also found that the incremental cost-effectiveness \42\ of 
$7,447 and $8,968/ton NOX for Units 1 and 2, respectively, 
was on the high end of what we had found to be reasonable in other 
determinations.\43\ Ultimately, we finalized the State's determination 
to require LNB/SOFA as BART controls with a corresponding emissions 
limit of 0.26 lb/MMBtu by March 4, 2019, for Jim Bridger Units 1 and 2, 
and to require an emissions limit of 0.07 lb/MMBtu (30-day rolling 
average) with the installation SCR as part of the State's long-term 
strategy to achieve reasonable progress by 2022 and 2021 for Jim 
Bridger Units 1 and 2, respectively.\44\
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    \39\ 77 FR 33053-54.
    \40\ Deciview is the unit of measurement on the deciview index 
scale for quantifying in a standard manner human perceptions of 
visibility. 40 CFR 51.301.
    \41\ 79 FR 5040, 5048. Note that the text at 79 FR 5048 
misstates the average cost-effectiveness for LNB/SOFA + SCR at Units 
1 and 2. The correct figures are stated in Tables 5 and 6 at 79 FR 
5040.
    \42\ The incremental cost-effectiveness of each NOX 
control technology on a dollar-per-ton of pollutant removed basis is 
calculated by dividing the difference of the total annual costs of 
one control technology compared to the total annual costs of the 
next most stringent control technology divided by the difference in 
the reduction in annual NOX emissions of one control 
technology compared to the reduction in annual NOX 
emissions of the next most stringent control technology. See 40 CFR 
part 51, appendix Y, IV.D.e.
    \43\ 79 FR 5040, 5048.
    \44\ 79 FR 5048, 5049.
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B. November 2017 Regional Haze Progress Report

    Under the Regional Haze Rule, states are required to submit 
progress reports to the EPA documenting actual changes in visibility 
and emission reductions within the state.\45\ The first progress report 
must be in the form of a SIP revision and is due five years after 
submittal of the initial regional haze SIP.\46\ On November 28, 2017, 
Wyoming submitted its first progress report, which detailed the 
progress made toward achieving progress for visibility improvement and 
declared a determination of adequacy of the State's regional haze plan 
to meet reasonable progress goals.
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    \45\ 40 CFR 51.309.
    \46\ Id.
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    In June 2020, we approved Wyoming's progress report SIP 
revision.\47\ We found that between 2002 and 2008, Wyoming's 
NOX emissions were reduced by 57,296 tons, a 20 percent 
reduction during that time period. Additionally, we found that other 
haze-causing pollutants were also reduced between the same time 
period.\48\ We also found that all the monitoring sites within 
Wyoming's Class I areas showed improvement in visibility conditions 
between the baseline (2000-2004) and current (2005-2009) periods on 
both the 20 percent worst visibility and 20 percent best visibility 
days. When considering only anthropogenic impairment within the 
baseline (2000-2004) and most current (2012-2016) periods, all the 
monitoring sites also showed improvement on the 20 percent most 
impaired days.\49\
---------------------------------------------------------------------------

    \47\ 85 FR 21341 (April 17, 2020) (Proposed rule); 85 FR 38325 
(June 26, 2020) (Final rule).
    \48\ 85 FR 21346.
    \49\ Id at 21348.

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[[Page 25204]]

C. May 2020 Regional Haze SIP Revision

    On May 14, 2020, Wyoming submitted a proposed revision to its 
regional haze SIP for the long-term strategy at Jim Bridger Units 1 and 
2 (Wyoming's May 2020 SIP revision).\50\ The proposed revision included 
a four-factor reasonable progress analysis to replace the 0.07 lb/MMBtu 
(30-day rolling average) anticipated NOX reductions for Jim 
Bridger Units 1 and 2 as part of Wyoming's long-term strategy to 
improve visibility during the first planning period. Wyoming's May 2020 
SIP revision also included plant-wide (Units 1-4) month-by-month 
emission limits for NOX and SO2 (Table 2) as well 
as an annual total emissions cap of NOX and SO2 
for Units 1-4 of 17,500 tons/year.
---------------------------------------------------------------------------

    \50\ Letter dated May 12, 2020, from Todd Parfitt, Director, 
Wyoming Department of Environmental Quality, to Gregory Sopkin, 
Regional Administrator, EPA Region 8, Subject: State Implementation 
Plant Approval Request--Regional Haze 309(g) SIP revision for 
PacifiCorp Jim Bridger Power Plant.
---------------------------------------------------------------------------

    On January 18, 2022, the EPA proposed to disapprove Wyoming's May 
2020 SIP revision.\51\ Our proposed disapproval was based on the 
following: (1) the reasonable cost-effectiveness of the existing 
reasonable progress control requirements for Jim Bridger Units 1 and 2 
(emission limits of 0.07 lb/MMBtu consistent with the installation of 
SCR); (2) the appreciable visibility improvement estimated to result 
from compliance with the existing control requirements; and (3) the 
State's previous determination that the costs of those control 
requirements were reasonable and necessary to satisfy statutory 
requirements. The EPA also made the determination that Wyoming's 
proposed revision to replace its previously approved long-term strategy 
would not provide for similar or greater emissions reductions or 
visibility improvement as is required under the Clean Air Act and thus 
could not propose approval of Wyoming's May 2020 SIP revision. We have 
not issued a final rule for our proposed disapproval.
---------------------------------------------------------------------------

    \51\ 87 FR 2571 (January 18, 2022).
---------------------------------------------------------------------------

D. December 2022 Regional Haze SIP Revision

    On December 30, 2022, Wyoming submitted a regional haze SIP 
revision (Wyoming 2022 SIP revision).52 53 The Wyoming 2022 
SIP revision proposes to replace Wyoming's previously approved long-
term strategy with conversion of Jim Bridger Units 1 and 2 from coal-
firing to natural gas-firing by January 1, 2024, together with 
NOX emission and heat input limits, to allow for identical 
reasonable progress during the first planning period as would occur 
from the emission reductions from requiring a NOX emissions 
limit of 0.07 lb/MMBtu (30-day rolling average) at Jim Bridger Units 1 
and 2. The State also included monthly and annual NOX and 
SO2 emissions limits for Jim Bridger Units 1-4. On August 
31, 2023, Wyoming submitted a supplement containing associated permit 
amendments addressing heat input limit and monitoring, recordkeeping, 
and reporting requirements for Jim Bridger Units 1 and 2.\54\ On 
November 16, 2023, Wyoming submitted a supplement containing an amended 
permit to correct a typographical error found in the August 31, 2023, 
supplement.\55\
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    \52\ Letter dated December 30, 2022, from Todd Parfitt, 
Director, Wyoming Department of Environmental Quality, to KC Becker, 
Regional Administrator, EPA Region 8, Subject: Approval Request--
Parallel Process Regional Haze Round One State Implementation Plan 
(SIP) revision for PacifiCorp Jim Bridger Power Plant.
    \53\ On May 23, 2022, the state submitted a proposed SIP 
revision with a request to parallel process the draft SIP (letter 
dated May 20, 2022, from Todd Parfitt, Director, Wyoming Department 
of Environmental Quality, to KC Becker, Regional Administrator, EPA 
Region 8, Subject: Request to Parallel Process the Draft 309(g) 
Regional Haze Round 1 State Implementation Plan for PacifiCorp Jim 
Bridger Power Plant).
    \54\ Letter dated August 31, 2023, from Todd Parfitt, Director, 
Wyoming Department of Environmental Quality, to KC Becker, Regional 
Administrator, EPA Region 8, Subject: Supplemental Information for 
Wyoming's Parallel Process Regional Haze Round One State 
Implementation Plan (SIP) revision for PacifiCorp Jim Bridger Power 
Plant.
    \55\ Letter dated November 16, 2023, from Todd Parfitt, 
Director, Wyoming Department of Environmental Quality, to KC Becker, 
Regional Administrator, EPA Region 8, Subject: Supplemental 
Information for Wyoming's Parallel Process Regional Haze Round One 
State Implementation Plan (SIP) revision for PacifiCorp Jim Bridger 
Power Plant.
---------------------------------------------------------------------------

    The Wyoming 2022 SIP revision requires, beginning on January 1, 
2024, Jim Bridger Units 1 and 2 to meet a NOX emission limit 
of 0.12 lb/MMBtu (30-day rolling average) along with an annual 
NOX emission limit of 1,314 tons/year per unit, and a 41.6% 
reduction in maximum annual heat input limit equaling 21,900,000 MMBtu/
year per unit.\56\ As a result, the Wyoming 2022 SIP revision replaces 
the requirement for Jim Bridger Units 1 and 2 to comply with the 0.07 
lb/MMBtu emission limits in 2021 and 2022 (Table 1). The Wyoming 2022 
SIP revision does not, however, remove or revise the existing 
NOX BART determination for Jim Bridger Units 1 and 2 
(consistent with current LNB/SOFA NOX emissions controls) or 
change the existing reasonable progress emission limits of 0.07 lb/
MMBtu for Jim Bridger Units 3 and 4 (consistent with installed SCR 
emissions controls).
---------------------------------------------------------------------------

    \56\ The reduction in maximum annual heat input is based off the 
maximum annual heat input limit of 52,560,000 MMBtu/year per unit.

                                      Table 1--Existing and Proposed NOX Emission Limits for Jim Bridger Units 1-4
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                      Proposed NOX reasonable progress
                                                                     Existing NOX BART     Existing NOX reasonable             emission limits
                                                                   emission limit (30-day  progress emission limit -------------------------------------
                              Unit                                  rolling average; lb/       (30-day rolling       NOX (30-day rolling
                                                                         MMBtu) \1\         average; lb/MMBtu) \2\   average; lb/MMBtu)     NOX (tons/
                                                                                                                                               year)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................................                     0.26                     0.07              \3\ 0.12       3 5 1,314
2...............................................................                     0.26                     0.07              \3\ 0.12       3 5 1,314
3...............................................................                     0.26                     0.07                \4\ NA              NA
4...............................................................                     0.26                     0.07                \4\ NA              NA
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Compliance date is March 4, 2019; no changes to the NOX BART emission limits are proposed.
\2\ Compliance dates for each is: Unit 1 = December 31, 2022; Unit 2 = December 31, 2021; Unit 3 = December 31, 2015; and Unit 4 = December 31, 2016.
\3\ Compliance date is January 1, 2024.
\4\ No change to existing NOX reasonable progress emission limit of 0.07 lb/MMBtu (30-day rolling average).
\5\ Correlates to a 41.67% reduction of the maximum heat input (52,560,000 MMBtu/year) or 21,900,000 MMBtu/year with a 0.12 lb NOX lb/MMBtu 30-day
  rolling average limit.


[[Page 25205]]

    In addition, the Wyoming 2022 SIP revision includes month-by-month 
NOX and SO2 emission limits across all four Jim 
Bridger units, as well as an enforceable annual plant-wide 
NOX plus SO2 emissions cap of 17,500 tons per 
year, effective January 1, 2022 (Table 2). The monthly emissions limit 
and annual emissions cap for Jim Bridger Units 1-4 are federally 
enforceable through reference to Wyoming air quality permit #P0025809. 
The final permit was issued on May 5, 2020.\57\
---------------------------------------------------------------------------

    \57\ Letter dated May 5, 2020, from Nancy E. Vehr, 
Administrator, Air Quality Division, Wyoming Department of 
Environmental Quality, to James Owens, Director, Environmental 
Services, PacifiCorp, Subject: Permit #P0025809 (Permit #0025809).

Table 2--Enforceable Monthly NOX and SO2 Emission Limits for Jim Bridger
                  Units 1-4, Effective January 1, 2022
------------------------------------------------------------------------
                                        Total units 1-4  Total units 1-4
                                          NOX emission     SO2 emission
                                             limit            limit
                 Month                 ---------------------------------
                                            Monthly          Monthly
                                         average basis    average basis
                                           (lb/hour)        (lb/hour)
------------------------------------------------------------------------
January...............................            2,050            2,100
February..............................            2,050            2,100
March.................................            2,050            2,100
April.................................            2,050            2,100
May...................................            2,200            2,100
June..................................            2,500            2,100
July..................................            2,500            2,100
August................................            2,500            2,100
September.............................            2,500            2,100
October...............................            2,300            2,100
November..............................            2,030            2,100
December..............................            2,050            2,100
------------------------------------------------------------------------
                                              Annual emissions cap
                                       ---------------------------------
    Total NOX plus SO2................          17,500 tons/year
------------------------------------------------------------------------

E. Wyoming's Reassessment of Reasonable Progress Under Long-Term 
Strategy

    To demonstrate that the replacement of 0.07 lb/MMBtu with natural 
gas conversion, NOX limits, and reduced heat inputs for Jim 
Bridger Units 1 and 2 provided equivalent emissions reductions 
previously approved by the EPA under long-term strategy, the State 
submitted a reasonable progress analysis for Jim Bridger Units 1 and 2 
in the Wyoming 2022 SIP revision.
    In its source-specific reasonable progress assessment for Jim 
Bridger Units 1 and 2, the State considered the four factors as 
required by 40 CFR 51.308(d)(1)(i)(A).
    In 2014, the EPA approved the State's decision to require 
NOX controls of 0.07 lb/MMBtu (30-day rolling average) on 
Jim Bridger Units 1-4 pursuant to its long-term strategy. The State did 
not conduct a reasonable progress four-factor analysis for any of the 
Jim Bridger units at that time but instead opted for controls under the 
long-term strategy provisions found under 40 CFR 51.308(d)(3).\58\ The 
State conducted its four-factor reasonable progress analysis for Jim 
Bridger Units 1 and 2 for the first time in connection with its 2020 
and 2022 SIP submittals to replace the emissions reductions approved 
for Jim Bridger Units 1 and 2 under the long-term strategy. This is 
acceptable since 40 CFR 51.308(d)(3) provides that a state's ``long-
term strategy must include enforceable emissions limitations, 
compliance schedules, and other measures as necessary to achieve the 
reasonable progress goals established by states having mandatory class 
I Federal areas.''
---------------------------------------------------------------------------

    \58\ See 77 FR 33040 (listing stationary sources evaluated under 
the four reasonable progress factors and not including Jim Bridger).
---------------------------------------------------------------------------

    Pursuant to 40 CFR 51.308(d)(1)(i)(A), in determining the measures 
necessary to make reasonable progress, a state must take into account 
the following four factors and demonstrate how they were taken into 
consideration in making a reasonable progress determination:
     Costs of Compliance;
     Time Necessary for Compliance;
     Energy and Non-Air Quality Environmental Impacts of 
Compliance; and
     Remaining Useful Life of Any Potentially Affected Sources.
1. Costs of Compliance
    For the source-specific reasonable progress analysis, Wyoming 
provided costs of compliance for three scenarios: (1) installation of 
SCR on Units 1 and 2 operating on coal, (2) installation of SCR on 
Units 1 and 2 operating on natural gas, and (3) conversion of Units 1 
and 2 from coal to natural gas, together with NOX and heat 
input limits. For the installation of SCR operating on coal and 
conversion from coal to natural gas scenarios, Wyoming used baseline 
NOX emission rates for LNB/SOFA of 0.187 lb/MMBtu for Unit 1 
and 0.192 lb/MMBtu for Unit 2 (annual average), reflective of the 
actual emissions rate (2013-2015) \59\ and used the 2001-2003 average 
annual heat input of 42,977,652 MMBtu/year and 40,898,999 MMBtu/year to 
calculate baseline NOX emissions in tons/year of 4,018 and 
3,926 for Units 1 and 2, respectively.\60\ For the installation of SCR 
operating on natural gas scenario, Wyoming used the stipulations in the 
consent decree \61\ as the baseline: NOX emission rate of 
0.12 lb/MMBtu (30-day rolling average) for both Units 1 and 2

[[Page 25206]]

and annual heat input of 21,900,000 MMBtu/year. The NOX 
emission rate for SCR operating on either coal or natural gas was 
assumed to be 0.05 lb/MMBtu (annual), while the NOX emission 
rate for conversion from coal to natural gas was assumed to be 0.12 lb/
MMBtu (30-day rolling average).\62\ Wyoming based total capital costs 
to install SCR ($140,428,000 for each Unit 1 and 2) on the actual costs 
incurred to install SCR technology on Jim Bridger Units 3 and 4.\63\ 
The total capital costs to convert Units 1 and 2 from coal-fired to 
natural gas-fired was found to be $14,632,077 and $14,151,451, 
respectively. The State annualized capital costs using the capital 
recovery factor approach described in the EPA's Control Cost Manual 
using amortization periods between one and 14 years reflective of each 
of the three different scenarios.64 65 Total annual costs 
were calculated as the sum of the annualized capital costs and total 
operation and maintenance costs. Finally, the cost-effectiveness of 
each scenario was calculated on a dollar-per-ton of pollutant removed 
basis by dividing the total annual costs by the reduction in annual 
NOX emissions associated with each scenario.
---------------------------------------------------------------------------

    \59\ Wyoming 2022 SIP revision, Appendix C at 2-3. Note: The 
Wyoming 2020 SIP revision identifies identical baseline 
NOX emission rates that reflect the actual emissions rate 
from 2013-2015.
    \60\ Wyoming 2022 SIP revision, cost supplement.
    \61\ Consent Decree, State of Wyoming v. PacifiCorp, Docket No. 
2022-CV-200-333, First Judicial District Court, Laramie, Wyoming. 
(February 14, 2022).
    \62\ Throughout, we refer to the averaging periods--annual 
average for 0.05 lb/MMBtu and 30-day rolling average for 0.12 lb/
MMBtu--which Wyoming provided in the Wyoming 2022 SIP revision. 
However, we recognize the need to adjust the averaging periods, as 
appropriate. Indeed, this concept is discussed in similar 
rulemakings for Wyoming (79 FR 5167 (January 30, 2014), 84 FR 10434 
(March 21, 2019)), and we discuss the impact of such adjustments in 
section IV. of this document.
    \63\ Wyoming 2022 SIP revision, Appendix C at 5. Note: The 
Wyoming 2022 SIP revision cites the February 4, 2019, S&L Report as 
the basis for the total capital costs.
    \64\ EPA, ``Cost Control Manual,'' Section 4, Chapter 2, June 
2019, page 80, available at https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution. (last visited February 2024).
    \65\ The amortization period in years for SCR operating on coal 
was 1.00 (December 2022-December 2023) and 1.67 (May 2022-December 
2023) for Units 1 and 2, respectively. The amortization period for 
SCR operating on natural gas and conversion from coal to natural gas 
was 14 (2024-2037) for both Units 1 and 2.
---------------------------------------------------------------------------

    Costs of compliance for Wyoming's reasonable progress analysis for 
Jim Bridger Units 1 and 2 is summarized in Table 3.\66\
---------------------------------------------------------------------------

    \66\ Wyoming 2022 SIP revision at 3, 4, and cost supplement.

           Table 3--Summary of Jim Bridger Units 1 and 2 NOX Revised Reasonable Progress Cost Analysis
----------------------------------------------------------------------------------------------------------------
                                               Assumed NOX        Emissions                        Average cost
                 Scenario                    emissions rate    reduction (tons    Total annual    effectiveness
                                               (lb/MMBtu)         per year)       cost ($/year)      ($/ton)
----------------------------------------------------------------------------------------------------------------
                                                     Unit 1
----------------------------------------------------------------------------------------------------------------
SCR operating on coal.....................          \1\ 0.05              2,944    $152,369,457          $51,756
SCR operating on natural gas..............          \1\ 0.05                766      18,036,235           23,531
Conversion from coal to natural gas \3\...          \2\ 0.12              2,704       4,018,476            1,486
----------------------------------------------------------------------------------------------------------------
                                                     Unit 2
----------------------------------------------------------------------------------------------------------------
SCR operating on coal.....................          \1\ 0.05              2,904      94,115,947           32,411
SCR operating on natural gas..............          \1\ 0.05                766      18,036,235           23,531
Conversion from coal to natural gas \3\...          \2\ 0.12              2,612       3,962,516            1,517
----------------------------------------------------------------------------------------------------------------
\1\ Based on an annual average.
\2\ Based on a 30-day rolling average.
\3\ Operating with a heat input limit of 21,900,000 MMBtu/year (equal to 41.6% of maximum annual heat input).

    Ultimately, Wyoming determined that conversion to natural gas 
without the installation of SCR is more cost-effective than conversion 
to natural gas with the addition of SCR particularly with the 
additional NOX and heat input reductions reflected in the 
consent decree.\67\
---------------------------------------------------------------------------

    \67\ Wyoming 2022 SIP revision at 4.
---------------------------------------------------------------------------

2. Time Necessary for Compliance
    The SIP approved by the EPA on January 30, 2014, requires an 
emission limit of 0.07 lb/MMBtu associated with the installation of 
LNB/SOFA + SCR on Jim Bridger Unit 1 by December 31, 2022, and on Unit 
2 by December 31, 2021. The current LNB/SOFA NOX emissions 
controls were installed in 2010 and 2005 for Units 1 and 2, 
respectively.\68\
---------------------------------------------------------------------------

    \68\ Id. at 6.
---------------------------------------------------------------------------

    Wyoming stated that because there is an enforceable commitment to 
cease coal operation and meet natural gas conversion limits at Jim 
Bridger Units 1 and 2 by January 1, 2024,\69\ SCR installation would 
take longer than the planned natural gas conversion. Furthermore, 
according to the State, installing SCR on a converted natural gas unit 
makes no practical or economic sense.
---------------------------------------------------------------------------

    \69\ Consent Decree, Wyoming v. PacifiCorp, Docket No. 2022-CV-
200-333. First Judicial District Court, Laramie, Wyoming. (February 
14, 2022).
---------------------------------------------------------------------------

3. Energy and Non-Air Quality Environmental Impacts of Compliance
    Wyoming determined that the conversion to natural gas will result 
in fewer overall energy and environmental impacts when compared to the 
installation of SCR, including fewer impacts from: mercury (Hg), 
greenhouse gases (GHG), carbon monoxide (CO), carbon dioxide 
(CO2), PM, sulfuric acid (H2SO4), coal 
and natural gas consumption, coal combustion residual (CCR) production 
and disposal, and raw water consumption associated with the burning of 
coal. Additionally, Wyoming also determined that SCR control technology 
would require the storage and use of ammonia and would create more CCR. 
Wyoming also notes that fewer GHGs will be produced with the gas 
conversion compared to SCR, and that the gas conversion would reduce 
the Jim Bridger plants auxiliary load demand by approximately 10.4 
megawatts of energy compared to SCR. Finally, the State noted that the 
requirements relating to the natural gas conversion effectively limit 
the average annual capacity factor (heat input) for Units 1 and 2 to 
approximately 42%, resulting in significant reductions in the 
consumption of natural resources.
4. Remaining Useful Life
    For the Wyoming 2022 SIP revision, Wyoming evaluated each emission 
control technology scenario for Jim Bridger Units 1 and 2 using the 
year 2024 as the end of remaining useful life on coal and the year 2037 
as the end of remaining useful life on natural gas.\70\
---------------------------------------------------------------------------

    \70\ Wyoming 2022 SIP revision at 4.

---------------------------------------------------------------------------

[[Page 25207]]

5. Reasonable Progress Demonstration
    Upon completion of a reasonable progress four-factor analysis, 
states must demonstrate how the four factors were taken into 
consideration in making a reasonable progress determination for each 
class I area within the state.\71\ Taking into consideration the four 
statutory reasonable progress factors described previously, Wyoming 
determined that the conversion of Units 1 and 2 from coal-firing to 
natural gas-firing, together with NOX emission and heat 
input limits, provided greater reasonable progress at a lower cost and 
with fewer negative environmental impacts when compared to SCR as 
reflected in the 2014 final rule. Accordingly, Wyoming's 2022 SIP 
revision replaces the emission limits of 0.07 lb/MMBtu (30-day rolling 
average) associated with SCR installation at Jim Bridger Units 1 and 2 
with natural gas conversion together with NOX emission and 
heat input limits at those same units as part of the State's long-term 
strategy to achieve reasonable progress for the first planning 
period.\72\
---------------------------------------------------------------------------

    \71\ 40 CFR 51.308(d)(1)(i)(A).
    \72\ Wyoming 2022 SIP revision at 8.
---------------------------------------------------------------------------

F. Summary of Wyoming's Additional Proposed Revisions to the Emission 
Limits for Jim Bridger

    In addition to Wyoming's revised emission reductions derived from 
the conversion to natural gas and associated NOX limits, and 
reduced heat input for Jim Bridger's Units 1 and 2 under the reasonable 
progress analysis, the State is requiring monthly and annual 
NOX and SO2 emission limits for Jim Bridger Units 
1-4 (summarized in Table 2) and an annual plant-wide NOX and 
SO2 emissions cap of 17,500 tons per year, federally 
enforceable through reference to permit #P0025809, which is effective 
through December 31, 2023.

IV. The EPA's Evaluation and Proposed Approval of Wyoming's Regional 
Haze SIP Revisions

    For the reasons described in this section, the EPA proposes to 
approve Wyoming's 2022 SIP revision. The proposed Wyoming 2022 SIP 
revision adds a source-specific NOX reasonable progress 
analysis and determination for Jim Bridger Units 1 and 2 and finds 
conversion from coal-firing to natural gas-firing, together with 
NOX emission and heat input limits, to be sufficient for 
reasonable progress and long-term strategy during the first planning 
period and that the emission limits associated with the installation of 
SCR are no longer required. Separately, we are also proposing to 
approve Wyoming's monthly and annual NOX and SO2 
emission limits for Jim Bridger Units 1-4. Our proposed action is based 
on an evaluation of Wyoming's regional haze SIP submittal under the 
regional haze requirements at 40 CFR 51.300-51.309 and CAA section 169A 
and 169B. The Wyoming 2022 SIP revision was also evaluated for 
compliance with the general SIP requirements contained in CAA section 
110 and other provisions of the CAA and our regulations applicable to 
this action. The EPA proposes to approve the Wyoming 2022 SIP revision 
as meeting the relevant statutory and regulatory requirements. Where 
appropriate, we provide additional rationale to supplement the State's 
analysis and to support our conclusions. The EPA is not reopening, and 
thus not accepting comment on, the EPA's 2014 approval of Wyoming's 
BART determinations for Jim Bridger Units 1-4, the EPA's 2014 approval 
of the emission limits Wyoming required as long-term strategy controls 
for Jim Bridger Units 3 and 4, or the EPA's 2022 proposed disapproval 
of Wyoming's 2020 SIP revision. Any comments on these issues are beyond 
the scope of this action and will not be addressed in this rulemaking.

A. The EPA's Proposed Approval of Wyoming's Reasonable Progress 
Determination for Jim Bridger Units 1 and 2

    We are proposing to approve Wyoming's December 2022 regional haze 
SIP revision pertaining to the State's reasonable progress 
NOX determinations for Jim Bridger Units 1 and 2.
    In our analysis of Wyoming's 2022 SIP revision, we evaluated 
Wyoming's reasonable progress determination for Jim Bridger Units 1 and 
2 under 40 CFR 51.308(d)(1)(i)(A). As a threshold matter and given the 
considerably shortened remaining useful life of the existing coal-fired 
boilers due to the proposed natural gas conversion, we propose to find 
that it is appropriate for Wyoming to reassess its existing long-term 
strategy to achieve reasonable progress for Jim Bridger Units 1 and 2 
by conducting a four-factor analysis.
1. Basis for the EPA's Proposed Approval
    Our proposed approval is based on the following: (1) the fact that 
this is a first planning period reasonable progress determination for 
BART sources; (2) the costs of compliance; and (3) an analysis of 
projected emissions reductions achievable.
    As explained in the EPA's 2007 Reasonable Progress Guidance for the 
first planning period, states have latitude to determine appropriate 
additional control requirements for ensuring reasonable progress.\73\ 
Unlike BART, which contains very specific applicability criteria to 
procure, install, and operate the best available retrofit technology 
and a regulatory framework for how states perform a ``one-time'' 
evaluation of emissions controls for the first planning period, the 
procedure for determining what controls are necessary to make 
reasonable progress is not as specific and a reasonable progress 
analysis is performed each planning period.\74\ Thus, although states 
must consider the four statutory factors, at a minimum, in determining 
reasonable progress, states also have more flexibility in how to take 
these factors into consideration.\75\ The text of the CAA and case law 
likewise support affording states deference in their reasonable 
progress determinations, provided those determinations are reasonable 
given the applicable statutory and regulatory requirements and purpose 
of the regional haze program.\76\
---------------------------------------------------------------------------

    \73\ The EPA's 2007 Guidance at page 4-2.
    \74\ Compare 40 CFR 51.308(e) and part 51, appendix Y with 40 
CFR 51.308(d).
    \75\ The EPA's 2007 Guidance at page 5-1.
    \76\ 42 U.S.C. 7407(a) (``Each State shall have the primary 
responsibility for assuring air quality within [its] entire 
geographic area.''); id. section 7401(a)(3) (``[A]ir pollution 
prevention . . . is the primary responsibility of States and local 
governments.''); Oklahoma v. EPA, 723 F.3d 1201, 1204 (10th Cir. 
2014) (``The Clean Air Act uses a cooperative federalism approach to 
regulate air quality.'') (Internal quotation marks omitted), 
Luminant Generation Co. v. EPA, 675 F.3d 917, 921 (5th Cir. 2012) 
(Congress gave states ``the primary responsibility for implementing 
[air quality] standards.'') (Internal quotation marks omitted); 
Union Elec. Co. v. EPA, 427 U.S. 246, 250 (1976) (states have ``wide 
discretion'' in formulating SIPs).
---------------------------------------------------------------------------

    Furthermore, the EPA's 2007 Guidance provides that reasonable 
progress analyses for the first implementation period are conducted 
against the backdrop of a state's BART determinations. In particular, 
the EPA's 2007 Guidance states that, given the overlap between the 
statutory BART and reasonable progress factors, it may be reasonable to 
conclude that any controls required pursuant to a BART determination 
for a source also satisfy the reasonable progress-related requirements 
for that source.\77\ Here, the two sources (Units 1 and 2) being 
analyzed are BART sources for which BART determinations were made and 
emission limits were required. In its 2022 SIP revision, Wyoming 
considered what, if any, controls should be required in addition to the 
BART controls

[[Page 25208]]

determined appropriate (LNB/SOFA) for the first planning period. 
Specifically, the State performed a reasonable progress four-factor 
analysis for Jim Bridger Units 1 and 2 to analyze whether it was 
appropriate to remove the existing 0.07 lb/MMBtu emission limits 
associated with SCR in addition to the five-factor BART analysis it 
performed previously. We propose to find that the outcome of that 
analysis--that the conversion of Jim Bridger Units 1 and 2 from coal-
firing to natural gas-firing, together with NOX emission and 
heat input limits, makes reasonable progress for the first 
implementation period--is not unreasonable and is supported by the 
EPA's 2007 Guidance and Regional Haze Rule.\78\
---------------------------------------------------------------------------

    \77\ See the EPA's 2007 Guidance at pages 4-2--4-3.
    \78\ 40 CFR 51.308(d)(1).
---------------------------------------------------------------------------

a. Costs of Compliance
    In its reasonable progress analysis for Jim Bridger Units 1 and 2, 
the statutory factor that appears to have been the most significant in 
Wyoming's reasonable progress determination is the costs of compliance. 
As an initial matter, we agree with Wyoming's reliance on the revised 
cost estimates reflected in Wyoming's 2022 SIP revision rather than the 
cost estimates from EPA's 2014 final rule. Specifically, based on our 
review, the following elements of Wyoming's revised cost calculation 
are appropriate: (1) the use of actual annual average (2013-2015) 
baseline NOX emissions rates for LNB/SOFA for the 
installation of SCR operating on coal and conversion from coal-firing 
to natural gas-firing scenarios; (2) the use of baseline NOX 
emissions rates reflected in the consent decree associated with the 
installation of SCR operating on natural gas scenario; (3) the use of 
NOX emissions rates of 0.05 lb/MMBtu (annual average) and 
0.12 lb/MMBtu (30-day rolling average) for the installation of SCR 
firing on coal or natural gas and the conversion from coal-firing to 
natural gas-firing, respectively; (4) the use of amortization periods 
of 1.00 (12 months) and 1.67 (20 months) for the installation of SCR 
firing coal on Units 1 and 2, respectively; and (5) the use of actual 
costs for the installation and operation of SCR derived from those 
costs incurred for Units 3 and 4. However, we disagree with Wyoming's 
amortization period for SCR firing on natural gas and for conversion 
from coal-firing to natural gas-firing scenarios and are therefore 
providing supplemental analysis to support our conclusions. 
Additionally, we are supplementing our cost calculations with a common 
baseline reflecting the maximum allowable heat input.
    With respect to control cost estimates, including amortization 
periods, our NOX control cost estimates in the reasonable 
progress analysis are based on the current version of the EPA's Control 
Cost Manual, which was revised in 2014 and, as updated, includes a 30-
year equipment life for SCR.\79\ The change in the equipment life 
estimate from 20 to 30 years for SCR affects annual cost estimates and 
average cost-effectiveness. The updated Control Cost Manual also 
requires the use of the source's ``firm-specific nominal rate'' of 
borrowing instead of the manual's prior instruction to use a 7% 
interest rate.\80\ In response to comments on Wyoming's 2020 SIP 
revision, PacifiCorp stated that its actual rate of borrowing is higher 
than 7%.\81\ Here, we note that PacifiCorp's actual rate of borrowing 
is 7.303% as provided in Wyoming's 2022 SIP revision.\82\ We agree that 
this approach is appropriate and consistent with the updated Control 
Cost Manual. However, we are proposing to find that the State did not 
use the appropriate amortization period for the installation of SCR on 
natural gas-firing and conversion from coal-firing to natural gas-
firing scenarios. In both of these scenarios, Wyoming used an 
amortization period of 14 years (2024-2037) based on the expected 
remaining useful life of Jim Bridger Units 1 and 2 found in 
PacifiCorp's 2021 Integrated Resource Plan (IRP).\83\ Because there is 
not an enforceable closure date in the Wyoming regional haze SIP that 
would effectively shorten the remaining useful life of Jim Bridger 
Units 1 and 2, we find that the Cost Control Manual requires that the 
default remaining useful life (30 years) be used as the amortization 
period of the control technologies being evaluated in the cost 
analyses.\84\
---------------------------------------------------------------------------

    \79\ EPA, ``Cost Control Manual,'' Section 4, Chapter 2, June 
2019, page 80, available at https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution (last visited February 2024).
    \80\ Id. at Section 1, Chapter 2, November 2017, pages 14-17, 
available at https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution (last 
visited February 2024).
    \81\ Letter dated October 25, 2019, from James Owen, Director, 
Environmental, PacifiCorp, to Nancy Vehr, Administrator, Wyoming 
Department of Environmental Quality, Air Quality Division, at page 
7. (Originally submitted as part of Wyoming 2020 SIP revision).
    \82\ Wyoming 2022 SIP revision, cost supplement.
    \83\ Wyoming 2022 SIP revision at 3.
    \84\ EPA, ``Cost Control Manual,'' Section 4, Chapter 2, June 
2019, page 80, available at https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution (last visited February 2024). However, we also note that 
PacifiCorp's 2021 Integrated Resource Plan Update lists retirement 
for Jim Bridger Units 1 and 2 as 2037. PacifiCorp, ``PacifiCorp 
Integrated Resource Plan Update,'' March 2022, page 13.
---------------------------------------------------------------------------

    With respect to the baseline NOX emissions rates, 
Wyoming's cost analyses assessed the installation of SCR operating on 
coal and conversion to natural gas scenarios against a 2001-2003 
baseline heat input of 42,977,652 MMBtu/year and 40,898,999 MMBtu/year 
for Units 1 and 2, respectively, and 2013-2015 baseline NOX 
emission rates for LNB/SOFA. Because reasonable progress analyses for 
BART sources in the first implementation period are conducted to 
determine what, if anything, in addition to BART is necessary to make 
reasonable progress and are a separate control determination than 
BART,\85\ and because BART controls (LNB/SOFA) are already installed 
and operating on these units, we believe it was reasonable for Wyoming 
to consider the cost of potential reasonable progress controls (SCR 
operating on coal and conversion to natural gas) relative to a baseline 
of BART (2013-2015 baseline NOX emission rates for LNB/SOFA) 
and the 2001-2003 baseline heat input figures. Moreover, because the 
installation of controls (SCR) operating on natural gas scenario 
reflects a baseline associated with natural gas firing instead of coal-
firing, we also believe it was reasonable for Wyoming to use the 
baseline heat input (21,900,000 MMBtu/year) and NOX emission 
limits (0.12 lb/MMBtu; 1,314 tons/year) required in the consent decree 
for both Units 1 and 2. Thus, as previously stated, we agree with the 
State and find the baselines appropriate for each of the three 
scenarios.
---------------------------------------------------------------------------

    \85\ The EPA's 2007 Guidance at page 4-2.
---------------------------------------------------------------------------

    While the Regional Haze Rule does not require states to consider 
fuel switching (e.g. from coal to natural gas) as control options, 
states are free to do so.\86\ In Wyoming and other states, we have 
approved state-adopted requirements for switching fuels, which have 
usually been negotiated between the source operator and the state.\87\ 
Thus, because, as previously described, this is not a BART 
determination, and because two of the control scenarios (conversion 
from coal to natural gas and installation of SCR operating on natural 
gas) involve fuel switching from coal to natural gas, we believe it is 
also reasonable to consider the cost using a common baseline reflecting 
potential-to-emit (e.g., allowable) baseline NOX emissions 
rather than the historical baseline emissions reflective of coal-

[[Page 25209]]

firing. We therefore conducted an additional cost analysis using the 
maximum allowable heat input limit of 52,560,000 MMBtu/year from 
Wyoming's 2009 BART Application Analysis as the baseline for potential 
further controls along with the 30-year amortization period for the SCR 
on natural gas and conversion from coal-firing to natural gas-firing 
scenarios (Table 4).88 89
---------------------------------------------------------------------------

    \86\ 40 CFR part 51, appendix Y.
    \87\ 83 FR 31332 (July 5, 2018), 84 FR 10433 (March 21, 2019).
    \88\ See `Firing Rate' in Wyoming BART Application Analysis (AP-
6040), page 3. (May 28, 2009).
    \89\ EPA Supplemental NOX Revised Reasonable Progress 
Analysis. March 13, 2024.

      Table 4--The EPA's Summary of Jim Bridger Units 1 and 2 NOX Revised Reasonable Progress Cost Analysis
----------------------------------------------------------------------------------------------------------------
                                              NOX emissions       Emissions                        Average cost
                 Scenario                    rate (lb/MMBtu)   reduction (tons    Total annual    effectiveness
                                                                  per year)       cost ($/year)      ($/ton)
----------------------------------------------------------------------------------------------------------------
                                                     Unit 1
----------------------------------------------------------------------------------------------------------------
SCR operating on coal.....................          \1\ 0.05              3,600    $152,369,457          $42,321
SCR operating on natural gas..............          \1\ 0.05                767      13,355,567           17,424
Conversion from coal to natural gas \3\...          \2\ 0.12              3,600       3,530,769              981
----------------------------------------------------------------------------------------------------------------
                                                     Unit 2
----------------------------------------------------------------------------------------------------------------
SCR operating on coal.....................          \1\ 0.05              3,732      94,115,947           25,220
SCR operating on natural gas..............          \1\ 0.05                767      13,355,567           17,424
Conversion from coal to natural gas \3\...          \2\ 0.12              3,732       3,490,829              935
----------------------------------------------------------------------------------------------------------------
\1\ Based on an annual average.
\2\ Based on a 30-day rolling average.
\3\ Operating with a heat input limit of 21,900,000 MMBtu/year (equal to 41.6% of maximum annual heat input).

    Thus, when comparing Wyoming's cost estimates (Table 3) with our 
revised cost estimates (Table 4) using a common baseline maximum heat 
input and 30-year amortization periods for SCR on natural gas and 
conversion from coal-fired to natural gas-fired scenarios, the average 
cost-effectiveness for SCR on coal for Units 1 and 2, respectively, are 
$51,756 and $32,411 per ton of NOX reduced using Wyoming's 
cost estimates and $42,321 and $25,220 per ton of NOX 
reduced using the EPA's revised cost estimates. The average cost-
effectiveness for SCR on natural gas for Units 1 and 2, respectively, 
are $23,531 and $23,531 per ton of NOX reduced using 
Wyoming's cost estimates and $17,424 and $17,424 per ton of 
NOX reduced using the EPA's revised cost estimates. The 
average cost-effectiveness for converting from coal-fired to natural 
gas-fired for Units 1 and 2, respectively, are $1,486 and $1,517 per 
ton of NOX reduced using Wyoming's cost estimates and $981 
and $935 per ton of NOX reduced using the EPA's revised cost 
estimates. As explained previously, while the EPA believes it is 
appropriate for Wyoming to consider the cost of potential reasonable 
progress controls (SCR operating on coal and conversion to natural gas) 
relative to a baseline of BART (2013-2015 baseline NOX 
emission rates for LNB/SOFA) using 2001-2003 baseline heat input, 
comparing the potential reasonable progress controls, including the 
conversion to a different fuel source, to a common baseline reflecting 
the maximum allowable heat input of the source (as well as appropriate 
amortization periods) is appropriate. To that end, the average cost-
effectiveness for all three scenarios is reduced using the EPA's 
revised cost estimates compared to Wyoming's cost estimates.
    Nevertheless, despite the reductions in average cost-effectiveness 
reflected in the EPA's revised cost estimates, we agree with Wyoming's 
consideration of cost-effectiveness and rejection of SCR operating on 
coal and operating on natural gas as reasonable progress controls 
because the cost-effectiveness figures for these controls are well 
above controls similarly determined in other first planning period 
actions to be too costly. For example, at the Antelope Valley Station 
power plant in North Dakota (Units 1 and 2), we determined that 
reasonable progress for NOX required an emission-limit 
corresponding to LNB (0.17 lb/MMBtu).\90\ The average cost-
effectiveness values for LNB at each unit were $586 and $661 per ton 
and that level of control was predicted to achieve NOX 
reductions of approximately 3,500 tons per unit. The average cost-
effectiveness for LNB + SCR at each unit were $6,746/ton and $7,606/ton 
and that level of control was predicted to achieve NOX 
reductions of approximately 6,500 tons per unit. We ultimately excluded 
LNB + SCR because the cost-effectiveness values were much higher than 
LNB. We therefore concluded that requiring higher performing controls 
during the first planning period was not reasonable.\91\ Similarly, we 
are proposing here to approve Wyoming's determination that a higher 
performing control, in this case SCR \92\ operating on coal or natural 
gas, is not reasonable given the cost-effectiveness and consideration 
of the other statutory factors discussed in this document. Here, the 
cost of SCR controls installed at Jim Bridger Units 1 and 2 whether on 
coal-fired or natural gas-fired boilers is significantly greater than 
the cost of conversion from coal to natural gas.
---------------------------------------------------------------------------

    \90\ 76 FR 58570, 58632 (September 21, 2011); 77 FR 20894, 
20896-97, 20899 (April 6, 2012). LNB here refers to LNB with close-
coupled overfire air and SOFA.
    \91\ 76 FR at 58631-32; 77 FR at 20899.
    \92\ Antelope Valley was not a BART source and did not have LNB 
installed at the time of the reasonable progress analysis; 
therefore, LNB was assessed as a potential reasonable progress 
control in addition to LNB + SNCR and LNB + SCR. In contrast, Jim 
Bridger Units 1 and 2 are operating LNB/SOFA pursuant to those 
units' BART determinations.
---------------------------------------------------------------------------

    In addition to the Antelope Valley Station, we are also proposing 
to find that Wyoming's determinations were reasonable and supported by 
the EPA's reasonable progress determination for Tucson Electric Power's 
Springerville Generating Station in Arizona (Springerville). For 
Springerville, cost effectiveness was analyzed after the installation 
of LNB with over-fire air (LNB/OFA) similar to the analysis of Jim 
Bridger Units 1 and 2 with LNB/SOFA controls already installed (see 
Tables 3 and 4). The Springerville Generating

[[Page 25210]]

Station contains four units, and like Jim Bridger, Springerville Units 
3 and 4 already had SCR controls installed at the time of the 
reasonable progress analysis for Units 1 and 2. We determined the 
average cost-effectiveness for SCR at Springerville Units 1 and 2 to be 
$6,829 per ton and $6,085 per ton, respectively.\93\ Ultimately, we 
concluded that the visibility benefit of SCR, while larger at 0.41 
deciviews at the most impacted Class I area, did not warrant the 
relatively high cost of controls for purposes of reasonable progress in 
the first planning period.\94\
---------------------------------------------------------------------------

    \93\ 79 FR 9318, 9359 (February 18, 2014).
    \94\ 79 FR 9360; see also 79 FR 52420, 52420 (September 3, 
2014).
---------------------------------------------------------------------------

    Wyoming did not assess visibility impacts; thus, we are not 
assessing visibility impacts in our review. Nevertheless, the average 
cost effectiveness associated with the installation of SCR on either 
the coal-fired or natural-gas fired boilers would be much higher than 
those we found unreasonable on Springerville Units 1 and 2.
b. Other Statutory Factors
    Of the four reasonable progress factors, cost was the most 
significant factor in our analysis of controls for Units 1 and 2. 
However, we also considered the other three statutory factors: time 
necessary for compliance, energy and non-air quality environmental 
impacts, and remaining useful life.
    With respect to time necessary for compliance, the December 31, 
2022, and December 31, 2021, compliance deadlines to install SCR on Jim 
Bridger Units 1 and 2 have existed since 2014. Therefore, we do not 
agree with the State that the time necessary for compliance is ``no 
longer accurate or relevant.''
    Relevant to energy and non-air quality environmental impacts, the 
EPA's 2007 Guidance references the EPA's BART Guidelines, which 
provide, among other things, that (1) the fact that a control 
technology uses energy in and of itself does not disqualify that 
technology, and (2) the fact that a control technology creates waste 
that must be disposed of does not necessarily suggest selection of that 
technology is unwarranted, especially if the control has been applied 
to similar facilities elsewhere and the waste is similar to those other 
applications.\95\ The 2007 Guidance also provides that to the extent 
energy and non-air quality environmental impacts of compliance are 
quantifiable, they should be included in the engineering analysis 
supporting the cost of compliance estimates.\96\ Wyoming analyzed and 
included relevant information in this regard in its revised cost 
analysis for the Wyoming 2022 SIP revision.\97\ We also agree with the 
State that the requirements relating to natural gas conversion 
effectively limits the average annual capacity factor (heat input) to 
approximately 42%, which is significant and may result in reducing the 
consumption of natural resources.
---------------------------------------------------------------------------

    \95\ The EPA's 2007 Guidance at pages 5-2 and 5-3; 40 CFR part 
51, appendix Y, IV.D.4.h-i.
    \96\ The EPA's 2007 Guidance at pages 5-2 and 5-3.
    \97\ Wyoming 2022 SIP revision, cost supplement.
---------------------------------------------------------------------------

    With respect to remaining useful life, we agree with the State that 
the remaining useful life of the existing coal-fired boilers under the 
SCR on coal-firing scenario is shortened to the end of 2023 by the 
enforceable provisions in the consent decree. However, as stated 
previously, the State did not provide an enforceable closure mechanism 
that would ensure that the remaining useful life of Jim Bridger Units 1 
and 2 under the natural gas conversion and SCR on natural gas-firing 
scenarios would not extend beyond 2037.
    Overall, despite disagreeing with certain aspects of Wyoming's 
reasonable progress analyses, consideration of the three other 
statutory factors--remaining useful life, time necessary for 
compliance, and energy and non-air quality environmental impacts--does 
not alter analysis that the costs of compliance is the determining 
factor for the selection of controls at Jim Bridger Units 1 and 2.
c. Analysis of Projected Emissions Reductions Achievable
    We also analyzed the three scenarios based on their associated 
NOX emissions and emissions reductions achievable (Tables 5 
and 6).

  Table 5--Jim Bridger Units 1 and 2 Emissions Limits When Converted to
                               Natural Gas
------------------------------------------------------------------------
          Permitted conversion                         NOX
------------------------------------------------------------------------
Coal-fired to natural gas-fired boilers  0.12 lb/MMBtu (30-day rolling
 \1\.                                     average) 1,314 tons/year.
------------------------------------------------------------------------
\1\ Operating with a heat input limit of 21,900,000 MMBtu/year (equal to
  41.6% of maximum annual heat input).


                   Table 6--Jim Bridger Units 1 and 2 Coal to Natural Gas Emissions Comparison
----------------------------------------------------------------------------------------------------------------
                                                                                         NOX
                                                                    --------------------------------------------
                                                                      Emission limit
               Fuel                       Permitted controls          (lb/MMBtu, 30-      Annual        Annual
                                                                        day rolling      emissions    reduction
                                                                         average)       (tons/year)  (tons/year)
----------------------------------------------------------------------------------------------------------------
Coal.............................  Existing controls + SCR.........          \1\ 0.07         1,314        3,600
Natural gas......................  Heat input limit, NOX limits....              0.12         1,314        3,600
----------------------------------------------------------------------------------------------------------------
\1\ Equivalent to 0.05 lb/MMBtu annual average.

    As previously discussed, the EPA approved Wyoming's NOX 
emission limit of 0.07 lb/MMBtu (30-day rolling average) for Jim 
Bridger Units 1 and 2 that reflected existing LNB/SOFA with the 
installation of SCR on both units under the State's long-term strategy. 
The installation of SCR on Jim Bridger Units 1 and 2 would reduce 
NOX emissions by 3,600 tons/year resulting in total 
NOX emissions of 1,314 tons/year when operated at maximum 
heat input. Likewise, the conversion from coal to natural gas, together 
with NOX emission and heat input limits, would result in an 
equivalent NOX emissions reduction of 3,600 tons/year 
resulting in equivalent total NOX emissions of 1,314 tons/
year. Thus, once Units 1 and 2 are converted from coal to natural gas 
under the conditions of the consent decree, the

[[Page 25211]]

NOX annual emissions are equivalent to the annual emissions 
achieved with coal-fired SCR controls.
    Notably, and as mentioned previously,\98\ we recognize the need to 
adjust the averaging periods (e.g., annual actual average, 30-day 
rolling average), as appropriate. In the Wyoming 2022 SIP revision, the 
State chose to use an annual NOX emissions rate of 0.05 lb/
MMBtu to represent the installation of SCR on coal-fired or natural 
gas-fired boilers, which we are proposing to find appropriate. 
Generally, the NOX annual average emission rate is based on 
the expected annual emission performance under a 30-day rolling average 
emission rate. The latter value will necessarily be higher than the 
former because of the shorter averaging period and a margin for 
compliance.
---------------------------------------------------------------------------

    \98\ See footnote #63.
---------------------------------------------------------------------------

    For example, the relationship between annual average and 30-day 
rolling average can be observed at Jim Bridger Units 3 and 4 which are 
subject to a 30-day rolling average emission limit of 0.07 lb/MMBtu and 
are achieving actual annual emission rates of approximately 0.05 lb/
MMBtu.\99\ Thus, we find that an estimated actual annual emission limit 
of 0.05 lb/MMBtu appropriately corresponds to the 30-day rolling 
average emission limit of 0.07 lb/MMBtu.
---------------------------------------------------------------------------

    \99\ 83 FR 55656, 55662 (November 7, 2018).
---------------------------------------------------------------------------

2. Summary of the EPA's Evaluation of Wyoming's Reasonable Progress 
Demonstration
    We are proposing to find that Wyoming's determination was not 
unreasonable based on the circumstances described herein. However, we 
note that it may be necessary to reassess higher performing controls 
for reasonable progress sources, including Jim Bridger Units 1 and 2, 
in future planning periods.\100\
---------------------------------------------------------------------------

    \100\ Wyoming's regional haze second planning period proposed 
SIP revision was due July 31, 2021. 40 CFR 51.308(f).
---------------------------------------------------------------------------

    Regardless, considering the fact that this is a first planning 
period reasonable progress determination for BART sources which the 
State has already required controls for the first planning period, the 
costs of compliance, and the analysis of projected emissions reductions 
achievable, it is not unreasonable for Wyoming to conclude that 
conversion from coal-firing to natural gas-firing, together with 
NOX emission and heat input limits, on Jim Bridger Units 1 
and 2 is sufficient to make reasonable progress in the first planning 
period. Thus, we are proposing to fully approve Wyoming's reasonable 
progress determination for Jim Bridger Units 1 and 2 for the first 
implementation period.

B. The EPA's Proposed Approval of Wyoming's Long-Term Strategy for Jim 
Bridger Units 1 and 2

    Under 40 CFR 308(d)(3), a state's ``long-term strategy must include 
enforceable emissions limitations, compliance schedules, and other 
measures as necessary to achieve the reasonable progress goals 
established by States having mandatory Class I Federal areas.'' Wyoming 
submitted the Wyoming 2022 SIP revision to replace the approved 
reductions under the long-term strategy with comparable emission 
reductions as analyzed under reasonable progress. As described in more 
detail previously, we are proposing to find that the conversion of Jim 
Bridger Units 1 and 2 to natural gas along with associated 
NOX limits and decreasing heat input, results in 
NOX annual emissions that are equivalent to the annual 
emissions achieved with coal-fired SCR controls (a reduction of 
NOX emissions by 3,600 tons/year resulting in total 
NOX emissions of 1,314 tons/year when operated at maximum 
heat input). Since reasonable progress is a subset of the requirements 
for the long-term strategy, adoption of the emission reductions under 
reasonable progress for Jim Bridger Units 1 and 2 will also ensure that 
the long-term strategy requirements are met. Because Wyoming has 
demonstrated that the proposed emissions reductions for Jim Bridger 
Units 1 and 2 under reasonable progress are equivalent to the long-term 
strategy emissions reductions Wyoming is proposing to replace for those 
same units, we are also proposing to approve Wyoming's reasonable 
progress NOX emissions limit derived for natural gas 
conversion and reduced heat inputs for Jim Bridger Units 1 and 2 as 
meeting the requirements of long-term strategy.

C. Monthly and Annual NOX and SO2 Emission Limits for Jim Bridger Units 
1-4

    Our proposed approval of Wyoming's reasonable progress 
determination for Jim Bridger Units 1 and 2 is based solely on the 
source-specific NOX reasonable progress analysis, as this 
analysis and determination pertains to NOX only. As 
previously stated, Wyoming did not provide a rationale or analysis for 
the inclusion of the monthly and annual NOX and 
SO2 emission limits. Furthermore, these limits include both 
NOX and SO2 emissions reductions which is outside 
of the scope of this proposed rulemaking. Nevertheless, we acknowledge 
that (1) per the EPA's 2007 Reasonable Progress Goals Guidance, Wyoming 
has discretion to evaluate factors (beyond the four statutory factors) 
that it considers relevant in formulating its long-term strategy,\101\ 
and (2) the inclusion of the monthly and annual NOX and 
SO2 emissions limits will reduce haze-causing pollutants. 
Indeed, the State has opted to adopt and make enforceable these monthly 
and annual NOX and SO2 emission limits, as 
proposed by PacifiCorp, through a state permit. Thus, we propose to 
find that these limits are relevant to Wyoming's progress towards 
natural visibility conditions at its Class I areas. However, because we 
are proposing that Wyoming's regional haze obligations under 40 CFR 
51.308(d)(1)(i)(A) are met by the determinations made pursuant to the 
NOX reasonable progress analysis, we propose to accept these 
limits solely as a SIP-strengthening measure, thus making them 
federally enforceable through incorporation and reference to Wyoming 
air quality permit #P0025809.\102\
---------------------------------------------------------------------------

    \101\ The EPA's 2007 Guidance at page 5-1.
    \102\ We are not evaluating the monthly and annual 
NOX and SO2 emission limits beyond our 
proposed acceptance of these limits as a SIP-strengthening measure.
---------------------------------------------------------------------------

D. Monitoring, Recordkeeping, and Reporting

    We are proposing to approve certain monitoring, recordkeeping, and 
reporting requirements found in Wyoming air quality permit #P0036941 
associated with the conversion from coal-firing to natural gas-firing 
which, if finalized, will replace the monitoring, recordkeeping, and 
reporting requirements associated with EPA's 2014 final rule found in 
40 CFR 52.2636(e) through 40 CFR 52.2636(k).\103\ We are also proposing 
to approve an additional monitoring, recordkeeping, and reporting 
condition into the SIP associated with permit #P0025809 related to the 
monthly and annual NOX and SO2 emission limits 
for Jim Bridger Units 1-4.\104\ The condition will be in addition to, 
and does not replace, existing requirements.\105\
---------------------------------------------------------------------------

    \103\ Permit #P0036941, Conditions 4, 5, 6, 10.i.1, 10.i.4, 17, 
18, 19, 20, and 21.
    \104\ Permit #P0025809, Condition 8.i.
    \105\ The monitoring, recordkeeping, and reporting requirements 
associated with Permit #P0025809 correspond to the monitoring, 
recordkeeping, and reporting requirements promulgated at 40 CFR 
52.2636(e) through 40 CFR 52.2636(k) and differ only as necessary to 
accommodate the differences in emissions rates used for the monthly 
annual NOX and SO2 emissions limits. 
Specifically, the monitoring, recordkeeping, and reporting 
requirements at 40 CFR 52.2636(e) through 40 CFR 52.2636(k) assume 
lb/MMBtu rates for NOX on a 30-day rolling basis, while 
the monitoring, recordkeeping, and reporting requirements for the 
monthly and annual NOX and SO2 emissions 
limits in Permit #P0025809 assume lb/hr rates for NOX and 
SO2 on a monthly-block basis.

---------------------------------------------------------------------------

[[Page 25212]]

    The BART emission limits for Units 3 and 4 identified for the Jim 
Bridger power plant in Table 1 of 40 CFR 52.2636 and associated 
NOX-related monitoring, recordkeeping, and reporting 
requirements found in 40 CFR 52.2636(e) through 40 CFR 52.2636(k) will 
remain in effect for the BART limits and reasonable progress limits 
will therefore not be impacted upon approval of our proposed revisions.

E. Consultation With Federal Land Managers

    There are seven Class I areas in the State of Wyoming. The United 
States Forest Service manages the Bridger Wilderness, Fitzpatrick 
Wilderness, North Absaroka Wilderness, Teton Wilderness, and Washakie 
Wilderness.\106\ The National Park Service manages Grand Teton National 
Park and Yellowstone National Park. The Regional Haze Rule grants the 
FLMs, regardless of whether an FLM manages a Class I area within the 
state, a special role in the review of regional haze implementation 
plans, summarized in section II.D. of this preamble.
---------------------------------------------------------------------------

    \106\ Our 2014 final rule modeled visibility improvement for six 
Class I areas in Wyoming (Bridger Wilderness, Fitzpatrick 
Wilderness, Teton Wilderness, Washakie Wilderness, Grand Teton 
National Park, and Yellowstone National Park) as well as three 
additional Class I areas in Colorado (Mt. Zirkel Wilderness, Rawah 
Wilderness, and Rocky Mountain National Park).
---------------------------------------------------------------------------

    Under 40 CFR 51.308(i)(2), Wyoming was obligated to provide the 
FLMs with an opportunity for consultation in development of the State's 
SIP revision no less than 60 days prior to the associated public 
hearing or public comment opportunity. On June 7, 2022, the State of 
Wyoming informed the FLMs of the State's draft proposed regional haze 
SIP revision for the Jim Bridger power plant. In doing so, the State 
provided the FLMs with a copy of the draft regional haze SIP revision 
and related consent decree \107\ and provided the FLMs with 60 days to 
provide comments as well as the opportunity to discuss the draft SIP 
during a phone call, if requested.\108\ The State received comments 
from the FLMs, made those comments available during the public comment 
period, and responded to the comments in the final SIP submittal.\109\ 
Therefore, we propose to find that Wyoming met its obligations for 
consultation in development of the State's draft regional haze SIP 
revision.
---------------------------------------------------------------------------

    \107\ Consent Decree, State of Wyoming v. PacifiCorp, Docket No. 
2022-CV-200-333. First Judicial District Court, Laramie, Wyoming. 
(February 14, 2022).
    \108\ Email from Amber Potts, Wyoming Department of 
Environmental Quality, to Federal Land Managers. June 7, 2022.
    \109\ Per the CAA 169A(d), states shall include a summary of the 
conclusions and recommendations of the FLMs in the notice to the 
public.
---------------------------------------------------------------------------

V. Clean Air Act Section 110(l)

    Under CAA section 110(l), the EPA cannot approve a plan revision 
``if the revision would interfere with any applicable requirement 
concerning attainment and reasonable further progress (as defined in 
section 7501 of this title), or any other applicable requirement of 
this chapter.'' \110\ The previous sections of the document explain how 
the Wyoming 2022 SIP revision will comply with applicable regional haze 
requirements and general implementation plan requirements, such as 
enforceability, and that annual NOX emissions are not 
greater than what is currently allowed in the SIP. There are no 
National Ambient Air Quality Standard (NAAQS) nonattainment areas in 
Wyoming for nitrogen dioxide (NO2) or PM.\111\ Likewise, 
there are also no NAAQS nonattainment areas in the State of Wyoming for 
SO2.
---------------------------------------------------------------------------

    \110\ Note that ``reasonable further progress'' as used in CAA 
section 110(l) is a reference to that term as defined in section 
301(a) (i.e., 42 U.S.C. 7501(a)), and as such means reductions 
required to attain the NAAQS set for criteria pollutants under 
section 109. This term as used in section 110(l) (and defined in 
section 301(a)) is not synonymous with ``reasonable progress'' as 
that term is used in the regional haze program. Instead, section 
110(l) provides that the EPA cannot approve plan revisions that 
interfere with regional haze requirements (including reasonable 
progress requirements) insofar as they are ``other applicable 
requirement[s]'' of the CAA.
    \111\ See Wyoming 2020 SIP revision at 13.
---------------------------------------------------------------------------

    With respect to ozone NAAQS nonattainment areas,\112\ the Upper 
Green River Basin ozone nonattainment area covers areas in Lincoln, 
Sublette, and Sweetwater counties and was designated nonattainment for 
the 2008 8-hour ozone NAAQS on July 20, 2012.\113\ On May 4, 2016, the 
EPA finalized a determination of attainment for the Upper Green River 
Basin nonattainment area.\114\ Based on the most recent 3 years of 
valid data at that time (2012-2014), the Upper Green River Basin 
attained the 2008 8-hour ozone NAAQS by the attainment date of July 20, 
2015, and continued to attain that standard during the most recent 
monitoring period (from 2020 to 2022).\115\ Thus, the Upper Green River 
Basin is attaining the 2008 8-hour ozone NAAQS at current emissions 
levels which would not increase under Wyoming's 2022 SIP revision 
because the proposed action results in emissions reductions equivalent 
to the previous SIP. In addition, the Upper Green River Basin is not a 
nonattainment area for the 2015 ozone NAAQS as it had an attaining 
design value of 63 ppb \116\ at the time of the designations in 2017. 
The current 2020-2022 preliminary design value is also attaining with a 
value of 67 ppb.\117\
---------------------------------------------------------------------------

    \112\ NOX is an ozone precursor.
    \113\ 77 FR 30088 (May 21, 2012).
    \114\ 81 FR 26697 (May 4, 2016).
    \115\ EPA, ``Air Quality System Preliminary Design Value 
Report,'' October 5, 2022.
    \116\ EPA, ``Ozone Design Values Report, 2016,'' October 2, 
2017.
    \117\ EPA, ``Upper Green River Basin 2020-2022 Preliminary Ozone 
Design Value Report,'' Row 18, October 5, 2022.
---------------------------------------------------------------------------

    Therefore, we propose to find that the Wyoming 2022 SIP revision is 
not anticipated to interfere with applicable requirements of the CAA 
and therefore CAA section 110(l) does not prohibit approval of this 
SIP.

VI. Summary of the EPA's Proposed Action

    In this action, the EPA is proposing to approve Wyoming's 2022 SIP 
revision for the NOX reasonable progress analysis and 
determination for Jim Bridger Units 1 and 2, including the associated 
emission and operational limitations, compliance dates, and monitoring, 
recordkeeping and reporting requirements as well as the separate 
monthly and annual NOX and SO2 emissions limits. 
Specifically, the EPA is proposing to approve the following as 
federally enforceable elements of the Wyoming 2022 SIP revision for Jim 
Bridger Units 1-4:
     The NOX emission limits found in Wyoming air 
quality permit #P0036941 (Condition 9 for NOX lb/MMBtu and 
tons/year emission limits) for Units 1 and 2.
     The NOX and SO2 emission limits 
found in Wyoming air quality permit #P0025809 (Condition 7 for lb/hr 
and Condition 9 for tons/year) for Units 1-4.
     The operational limit on annual heat input (based on a 12-
month rolling average of hourly heat input values) found in Wyoming air 
quality permit #P0036941 (Condition 19).
     The compliance dates found in Wyoming air quality permit 
#P0036941 (Conditions 11 and 16) requiring that Units 1 and 2 comply 
with NOX emission rates in lb/MMBtu (30-day rolling average) 
and tons/year as well as an annual heat input in MMBtu/year; and permit 
#P0025809 (Conditions 7 and 9) requiring that Units 1-4 comply with the 
NOX and SO2 emission limits in lb/hr and tons/
year, respectively.

[[Page 25213]]

     The monitoring, recordkeeping and reporting requirements 
found in Wyoming air quality permit #P0036941 (Conditions 4, 5, 6, 
10.i.1, 10.i.4, 17, 18, 19, 20, and 21) and permit #P0025809 (Condition 
8.i and 9).
    If the above elements are finalized into the SIP, the 0.07 lb/MMBtu 
NOX long-term emission limits for Jim Bridger Units 1 and 2 
will be removed from the SIP and replaced with the 0.12 lb/MMBtu 
NOX reasonable progress emission limit and associated 
NOX emissions and heat input limits, while the 0.07 lb/MMBtu 
NOX long-term strategy emission limits will remain for Units 
3 and 4.
    We are also proposing to approve the following non-enforceable 
elements of the Wyoming 2022 SIP revision for:
     Jim Bridger Units 1 and 2, Chapters 7.3.6 PacifiCorp Jim 
Bridger Electric Generating Station of Wyoming's regional haze 
narrative, Addressing Regional Haze Visibility Protection For The 
Mandatory Federal Class I Areas Required Under 40 CFR 51.309, which 
contain a source-specific NOX reasonable progress analysis.
     Jim Bridger Units 1-4, Chapter 8.3.3 Long-Term Control 
Strategies for BART Facilities (Jim Bridger Power Plant (Units 1 and 2) 
only) of Wyoming's regional haze narrative, Addressing Regional Haze 
Visibility Protection For The Mandatory Federal Class I Areas Required 
Under 40 CFR 51.309, which contains (1) plant-wide monthly 
NOX and SO2 emission limits and an annual 
emissions cap for NOX plus SO2; \118\ and (2) a 
compliance date to convert Units 1 and 2 to natural gas along with an 
associate NOX 30-day rolling average (lb/MMBtu), 
NOX annual emission cap (tons/year), and annual heat input 
(MMBtu/year).
---------------------------------------------------------------------------

    \118\ The revised text in Chapter 8 refers only to Jim Bridger 
Units 1 and 2. However, the monthly and annual NOX and 
SO2 emissions limits contained within the permit 
referenced, #P0025809, apply to Units 1-4 (Wyoming 2022 SIP revision 
at 8).

  Table 7--List of Wyoming SIP Amendments That the EPA Is Proposing To
                                 Approve
------------------------------------------------------------------------
 
-------------------------------------------------------------------------
Conditions of Wyoming Air Quality Permit #P0036941 Proposed for Approval
------------------------------------------------------------------------
Condition 9 for NOX lb/MMBtu and tons/year emission limits; Condition 11
 for fuel compliance date; Conditions 16, 19 for heat input limit and
 associated compliance date; and Conditions 4, 5, 6, 10.i.1, 10.i.4, 17,
 18, 19, 20, and 21 for associated monitoring, recordkeeping, and
 reporting requirements.
------------------------------------------------------------------------
Conditions of Wyoming Air Quality Permit #P0025809 Proposed for Approval
------------------------------------------------------------------------
Condition 7 (lb/hr emission limits) and 9 (tons/year emission limits)
 for NOX and SO2 monthly-block and annual emission limits and compliance
 dates, and Condition 8.i for associated monitoring, recordkeeping, and
 reporting requirements.
------------------------------------------------------------------------
  Amended Sections of Wyoming Regional Haze SIP Narrative Proposed for
                              Approval \1\
------------------------------------------------------------------------
Chapter 7.3.6, Chapter 8.3.3 (Jim Bridger Power Plant (Units 1 and 2)
 only)
------------------------------------------------------------------------
\1\ Wyoming 2022 SIP revision.

    Together these proposed amendments modify:
     40 CFR 52.2620(d)--air quality permit amendments adding 
(1) the requirement to convert to natural gas and associated 
NOX emissions limits and annual heat input for Jim Bridger 
Units 1 and 2, (2) the monthly and annual NOX and 
SO2 emission limits for Jim Bridger Units 1-4, and (3) 
associated monitoring, recordkeeping and reporting requirements;
     40 CFR 52.2620(e)--regional haze narrative amendments 
adding (1) a source-specific NOX reasonable progress 
analysis and determination for Jim Bridger Units 1 and 2 along with 
associated NOX emission limits and annual heat input, and 
(2) the monthly and annual NOX and SO2 emission 
limits for Jim Bridger Units 1-4; and
     40 CFR 52.2636(c)-(d)--NOX and SO2 
emissions limits, heat input, and associated compliance dates for Jim 
Bridger Units 1-4.
    The proposed revisions to both 40 CFR 52.2620 and 40 CFR 52.2636 
are included in this document. We are not proposing to change any other 
regulatory text in 40 CFR 52.2620 or 40 CFR 52.2636.

VII. Incorporation by Reference

    In this document, the EPA is proposing to include regulatory text 
in an EPA final rule that includes incorporation by reference. In 
accordance with the requirements of 1 CFR 51.5, the EPA is proposing to 
incorporate by reference the SIP amendments described in section VI. of 
this preamble. The EPA has made, and will continue to make, these 
materials generally available through https://www.regulations.gov 
(refer to docket EPA-R08-OAR-2022-0536) and at the EPA Region 8 Office 
(please contact the person identified in the FOR FURTHER INFORMATION 
CONTACT section of this preamble for more information).

VIII. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the Act and applicable 
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, the EPA's role is to approve state choices, 
provided that they meet the requirements of the CAA and applicable 
Federal regulations. Accordingly, this action merely proposes to 
approve state law as meeting Federal requirements and does not impose 
additional requirements beyond those imposed by state law. For that 
reason, this action:
     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 13563 (76 FR 3821, January 21, 
2011);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     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.);
     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);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or

[[Page 25214]]

safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 
1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     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 CAA; and
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where the 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).
    Executive Order 12898 (Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
Feb. 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. 
The 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.'' The 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.''
    The State 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. The EPA 
did not perform an EJ analysis and did not consider EJ in this 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. Consideration of EJ is not required as part of this 
action, and there is no information in the record inconsistent with the 
stated goal of E.O. 12898 of achieving environmental justice for people 
of color, low-income populations, and Indigenous peoples.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Greenhouse gases, Incorporation by reference, Intergovernmental 
relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting 
and recordkeeping requirements, Sulfur oxides, Volatile organic 
compounds.

    Authority: 42 U.S.C. 7401 et seq.

    Dated: April 2, 2024.
KC Becker,
Regional Administrator, Region 8.

    For the reasons stated in the preamble, the Environmental 
Protection Agency proposes to amend 40 CFR part 52 as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart ZZ--Wyoming

0
2. In Sec.  52.2620:
0
a. The table in paragraph (d) is amended by adding the entries ``Jim 
Bridger Units 1 and 2'' and ``Jim Bridger Units 1-4'' in alphabetical 
order at the end of the table.
0
b. The table in paragraph (e) is amended by revising the entry ``(25) 
XXV''.
    The additions and revision read as follows:


Sec.  52.2620  Identification of plan.

* * * * *
    (d) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                             Final rule citation/
          Regulation                  Rule title           State effective date        EPA effective date            date                 Comments
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
Jim Bridger Units 1 and 2.....  Air Quality SIP        August 29, 2023.............  [date 30 days after    [Federal Register      Only the following
                                 Permit containing                                    date of publication    citation of the        permit provisions:
                                 conversion to                                        of the final rule in   final rule], [date     NOX emission limits
                                 natural gas                                          the Federal            of publication of      (Condition 9 for NOX
                                 requirements,                                        Register].             the final rule in      lb/MMBtu and tons/
                                 P0036941.                                                                   the Federal            year emission
                                                                                                             Register].             limits); emission
                                                                                                                                    limit compliance
                                                                                                                                    date (Condition 11
                                                                                                                                    for fuel compliance
                                                                                                                                    date); heat input
                                                                                                                                    limit and associated
                                                                                                                                    compliance date
                                                                                                                                    (Condition 16, 19);
                                                                                                                                    and associated
                                                                                                                                    monitoring,
                                                                                                                                    recordkeeping, and
                                                                                                                                    reporting
                                                                                                                                    requirements
                                                                                                                                    (Conditions 4, 5, 6,
                                                                                                                                    10.i.1, 10.i.4, 17,
                                                                                                                                    18, 19, 20, and 21).

[[Page 25215]]

 
Jim Bridger Units 1-4.........  Air Quality SIP        5/5/2020....................  [date 30 days after    [Federal Register      Only the following
                                 Permit containing                                    date of publication    citation of the        permit provisions:
                                 additional                                           of the final rule in   final rule], [date     NOX and SO2 monthly-
                                 requirements,                                        the Federal            of publication of      block and annual
                                 P0025809.                                            Register].             the final rule in      emission limits
                                                                                                             the Federal            (P0025809 Condition
                                                                                                             Register].             7 for lb/hr emission
                                                                                                                                    limits, and
                                                                                                                                    Condition 9 for tons/
                                                                                                                                    year emission
                                                                                                                                    limits); emission
                                                                                                                                    limit compliance
                                                                                                                                    dates (P0025809,
                                                                                                                                    Conditions 7 and 9);
                                                                                                                                    and associated
                                                                                                                                    monitoring,
                                                                                                                                    recordkeeping, and
                                                                                                                                    reporting
                                                                                                                                    requirements
                                                                                                                                    (P0025809, Condition
                                                                                                                                    8.i).
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (e) * * *

----------------------------------------------------------------------------------------------------------------
                                            State
      Rule No.            Rule title      effective    EPA Effective        Final rule            Comments
                                            date            date          citation/date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
(25) XXV............  Wyoming State         5/23/22  [date 30 days      [Federal Register  Excluding portions of
                       Implementation                 after date of      citation of the    the following:
                       Plan for                       publication of     final rule],       Chapters 6.4, 6.5.7,
                       Regional Haze                  the final rule     [date of           6.5.8, and 7.5. EPA
                       for 309(g).                    in the Federal     publication of     disapproved (1) the
                                                      Register].         the final rule     NOX BART
                                                                         in the Federal     determinations for
                                                                         Register].         (a) Laramie River
                                                                                            Units 1-3, (b) Dave
                                                                                            Johnston Unit 3, and
                                                                                            (c) Wyodak Unit 1;
                                                                                            (2) the State's
                                                                                            monitoring,
                                                                                            recordkeeping, and
                                                                                            reporting
                                                                                            requirements for
                                                                                            BART units; and (3)
                                                                                            the State's
                                                                                            reasonable progress
                                                                                            goals.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

0
3. In Sec.  52.2636:
0
a. Revise table 1 in paragraph (c)(1).
0
b. Add tables 3 and 4 in numerical order in paragraph (c)(1).
0
c. Revise paragraph (d)(1).
    The revisions and additions read as follows:


Sec.  52.2636  Implementation plan for regional haze.

    (c) * * *
    (1) * * *

                        Table 1 to Sec.   52.2636
 [Emission limits for BART units for which the EPA approved the State's
              BART and Reasonable Progress determinations]
------------------------------------------------------------------------
                                                          NOX emission
                                         PM emission    limits- lb/MMBtu
        Source name/BART unit           limits-- lb/    (30-day rolling
                                            MMBtu           average)
------------------------------------------------------------------------
FMC Westvaco Trona Plant/Unit NS-1A..            0.05               0.35
FMC Westvaco Trona Plant/Unit NS-1B..            0.05               0.35
TATA Chemicals Partners (General                 0.09               0.28
 Chemical) Green River Trona Plant/
 Boiler C............................
TATA Chemicals Partners (General                 0.09               0.28
 Chemical) Green River Trona Plant/
 Boiler D............................
Basin Electric Power Cooperative                 0.03                N/A
 Laramie River Station/Unit 1........
Basin Electric Power Cooperative                 0.03                N/A
 Laramie River Station/Unit 2........
Basin Electric Power Cooperative                 0.03                N/A
 Laramie River Station/Unit 3........
PacifiCorp Dave Johnston Power Plant/           0.015                N/A
 Unit 3..............................
PacifiCorp Dave Johnston Power Plant/           0.015               0.15
 Unit 4..............................
PacifiCorp Jim Bridger Power Plant/              0.03          0.26/0.12
 Unit 1 \1\ \2\......................
PacifiCorp Jim Bridger Power Plant/              0.03          0.26/0.12
 Unit 2 \1\ \2\......................
PacifiCorp Jim Bridger Power Plant/              0.03          0.26/0.07
 Unit 3 \1\ \2\......................
PacifiCorp Jim Bridger Power Plant/              0.03          0.26/0.07
 Unit 4 \1\ \2\......................
PacifiCorp Naughton Power Plant/Unit             0.04               0.26
 1...................................
PacifiCorp Naughton Power Plant/Unit             0.04               0.26
 2...................................
PacifiCorp Wyodak Power Plant/Unit 1.           0.015                N/A
------------------------------------------------------------------------
\1\ The owners and operators of PacifiCorp Jim Bridger Units 1, 2, 3,
  and 4 shall comply with the NOX emission limit for BART of 0.26 lb/
  MMBtu and the PM emission limit for BART of 0.03 lb/MMBtu and other
  requirements of this section by March 4, 2019. The owners and
  operators of PacifiCorp Jim Bridger Units 1, 2, 3, and 4 shall comply
  with the NOX emission limit for reasonable progress of 0.12 lb/MMBtu
  by January 1, 2024, for Jim Bridger Units 1 and 2 and 0.07 lb/MMBtu by
  December 31, 2015, for Unit 3, and December 31, 2016, for Unit 4.

[[Page 25216]]

 
\2\ Additional NOX and SO2 emissions control measures and associated
  compliance dates for Jim Bridger Units 1-4, are found in Sec.
  52.2636(c) Tables 3 and 4.

* * * * *

                                            Table 3 to Sec.   52.2636
               [NOX and SO2 Emission Limits for Jim Bridger Units 1-4, Effective January 1, 2022]
----------------------------------------------------------------------------------------------------------------
                                                                  Total units 1-4 NOX      Total units 1-4 SO2
                                                                emission limit (monthly  emission limit (monthly
                             Month                              average basis) 1 2 (lb/  average basis) 1 2 (lb/
                                                                         hour)                    hour)
----------------------------------------------------------------------------------------------------------------
January.......................................................                    2,050                    2,100
February......................................................                    2,050                    2,100
March.........................................................                    2,050                    2,100
April.........................................................                    2,050                    2,100
May...........................................................                    2,200                    2,100
June..........................................................                    2,500                    2,100
July..........................................................                    2,500                    2,100
August........................................................                    2,500                    2,100
September.....................................................                    2,500                    2,100
October.......................................................                    2,300                    2,100
November......................................................                    2,030                    2,100
December......................................................                    2,050                   2,100
----------------------------------------------------------------------------------------------------------------
\1\ Effective January 1, 2022, through December 31, 2023.
\2\ In addition to monthly NOX and SO2 emission limits, an annual, plant-wide NOX plus SO2 emissions cap of
  17,500 tons per year is effective January 1, 2022, through December 31, 2023.


                                            Table 4 to Sec.   52.2636
            [NOX Emission Limits and Heat Input for Jim Bridger Units 1-2, Effective January 1, 2024]
----------------------------------------------------------------------------------------------------------------
                                                                   NOX emission limit
                             Unit                                     (tons/year)        Heat input (MMBtu/year)
----------------------------------------------------------------------------------------------------------------
Unit 1........................................................                    1,314               21,900,000
Unit 2........................................................                    1,314               21,900,000
----------------------------------------------------------------------------------------------------------------

* * * * *
    (d) Compliance date. (1) The owners and operators of PacifiCorp Jim 
Bridger Units 1, 2, 3, and 4 shall comply with the NOX 
emission limit of 0.26 lb/MMBtu and PM emission limit of 0.03 lb/MMBtu 
and other requirements of this section by March 4, 2019. The owners and 
operators of PacifiCorp Jim Bridger Units 1 and 2 shall comply with the 
NOX emission limit of 0.12 lb/MMBtu by January 1, 2024. The 
owners and operators of PacifiCorp Jim Bridger Units 3 and 4 shall 
comply with the NOX emission limit of 0.07 lb/MMBtu by: 
December 31, 2015, for Unit 3, and December 31, 2016, for Unit 4. The 
owners and operators of PacifiCorp Jim Bridger Units 1, 2, 3, and 4 
shall comply with the NOX and SO2 emission limits 
contained in Sec.  52.2636(c) Table 3 by January 1, 2022. The owners 
and operators of PacifiCorp Jim Bridger Units 1 and 2 shall comply with 
NOX emission and heat input limits contained in Sec.  
52.2636(c) Table 4 by January 1, 2024.
* * * * *
[FR Doc. 2024-07414 Filed 4-9-24; 8:45 am]
BILLING CODE 6560-50-P