[Federal Register Volume 87, Number 11 (Tuesday, January 18, 2022)]
[Proposed Rules]
[Pages 2571-2587]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-00777]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2020-0441; FRL-9443-01-R8]


Disapproval of Air Quality Implementation Plans; Wyoming; 
Proposed 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 
disapprove a State Implementation Plan (SIP) revision submitted by the 
State of Wyoming on May 14, 2020, and supplemented in September and 
October 2020, addressing regional haze (``Wyoming's 2020 SIP 
revision''). Wyoming's 2020 SIP revision reverses the State's 2011 
decision that emission limits consistent with the installation of 
selective catalytic reduction (SCR) for the Jim Bridger power plant, 
Units 1 and 2, are necessary to make reasonable progress under the 
State's long-term strategy for the first regional haze planning period. 
The SIP revision contains a source-specific nitrogen oxide 
(NO<INF>X</INF>) reasonable progress analysis and determination that 
currently installed controls (low-NO<INF>X</INF> burners with separated 
overfire air (LNB/SOFA)) are sufficient for reasonable progress during 
the first planning period for Jim Bridger Units 1 and 2, and that the 
emission limits associated with the installation of SCR are no longer 
necessary. The SIP revision also contains plant-wide monthly and annual 
NO<INF>X</INF> and sulfur dioxide (SO<INF>2</INF>) emission limits for 
the Jim Bridger power plant, Units 1-4. EPA is proposing to disapprove 
this SIP revision in full. The agency 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 
February 17, 2022.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2020-0441, 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 
www.regulations.gov. 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. 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 http://www.epa.gov/dockets/commenting-epa-dockets.

[[Page 2572]]

    Docket: All documents in the docket are listed in the 
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 
www.regulations.gov. To reduce the risk of COVID-19 transmission, for 
this action we do not plan to offer hard copy review of the docket. 
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: 
<a href="/cdn-cgi/l/email-protection#72161d1000131a1c17005c1813011e0b1c321702135c151d04"><span class="__cf_email__" data-cfemail="d0b4bfb2a2b1b8beb5a2febab1a3bca9be90b5a0b1feb7bfa6">[email protected]</span></a>.

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

I. What Action is EPA Proposing?
II. Background
    A. Requirements of the Clean Air Act and EPA's Regional Haze 
Rule
    B. Best Available Retrofit Technology
    C. Long-Term Strategy and Reasonable Progress Requirements
    D. Consultation with Federal Land Managers
III. Wyoming's Regional Haze SIP Revisions
    A. Background
    B. May 14, 2020 Submittal
    C. Summary of Wyoming's Reasonable Progress Reassessment
     1. Costs of Compliance
     2. Time Necessary for Compliance
     3. Energy and Non-Air Quality Environmental Impacts of 
Compliance
     4. Remaining Useful Life
     5. Visibility Improvement
     6. Reasonable Progress Demonstration
    D. Summary of Wyoming's Plant-Wide Monthly and Annual 
NO<INF>X</INF> and SO<INF>2</INF> Emission Limits for Jim Bridger
IV. EPA's Evaluation and Proposed Disapproval of Wyoming's Regional 
Haze SIP Revisions
    A. Basis for Proposed Disapproval
    B. EPA's Proposed Disapproval of Wyoming's Reasonable Progress 
Determination for Jim Bridger Units 1 and 2
    1. Basis of Our Proposed Disapproval
    a. Costs of Compliance
    b. Visibility Improvement
    c. Other Factors
    d. Summary of EPA's Evaluation of Wyoming's Reasonable Progress 
Demonstration
    C. Plant-Wide Monthly and Annual NO<INF>X</INF> and 
SO<INF>2</INF> Emission Limits for Jim Bridger Units 1-4
    D. Clean Air Act Section 110(l)
    E. Consultation With Federal Land Managers
V. Summary of EPA's Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is EPA proposing?

    On January 30, 2014, 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, EPA approved Wyoming's 
NO<INF>X</INF> best available retrofit technology (BART) emission 
limits of 0.26 lb/MMBtu (30-day rolling average) for Jim Bridger Units 
1-4, as well as the State's decision to include in its long-term 
strategy NO<INF>X</INF> reasonable progress emission limits of 0.07 lb/
MMBtu (30-day rolling average) for the same units, among other 
actions.\2\
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    \1\ 79 FR 5032 (January 30, 2014).
    \2\ The BART determination compliance date for all units was 
March 4, 2019. Reasonable progress 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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    Wyoming submitted its 2020 SIP revision on May 14, 2020.\3\ The SIP 
revision contains amendments to Chapters 7 and 8 of Wyoming's regional 
haze SIP narrative and would incorporate certain conditions of Wyoming 
air quality permit #P0025809 into the SIP.\4\ Together, the amendments 
provide a source-specific NO<INF>X</INF> reasonable progress analysis 
and determination for Jim Bridger Units 1 and 2, remove the 
NO<INF>X</INF> reasonable progress emission limits currently required 
for Jim Bridger Units 1 and 2, and add plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits for Jim Bridger Units 
1-4.\5\
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    \3\ At the request of EPA, Wyoming supplemented the original SIP 
submittal with additional documentation on September 8, 2020, and 
October 6, 2020.
    \4\ State of Wyoming, ``Addressing Regional Haze Visibility 
Protection For The Mandatory Federal Class I Areas Required Under 40 
CFR 51.309,'' Revised May 14, 2020 (``Wyoming 2020 SIP Revision'').
    \5\ Wyoming's SIP revision refers to these limits as ``voluntary 
visibility enhancing emission limits.'' They represent a separate 
SIP component from Wyoming's source-specific reasonable progress 
analysis and determination. The limits were voluntarily proposed by 
PacifiCorp to reduce regional haze causing pollutants. Wyoming 2020 
SIP Revision at 8-9.
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    EPA is proposing to disapprove this SIP revision in full. Our 
proposed disapproval is 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 consistent 
with the installation of SCR); (2) the appreciable visibility 
improvement estimated to result from compliance with the existing 
control requirements; and (3) the fact that the State previously 
determined that the costs of those control requirements were reasonable 
and that they are necessary to satisfy the statutory requirements, and 
has not provided any new information that would support a revised 
determination that the requirements are now unreasonable. In fact, the 
updated cost information provided by Wyoming indicates that SCR for 
these units is even more cost-effective than the State estimated in 
2011 and EPA estimated in its 2014 final rule, while the estimated 
visibility benefits remain the same as estimated in the 2014 final 
rule.
    Based on our proposed conclusions in section IV.B in this document, 
we propose to find that removing the SCR requirement would interfere 
with the regional haze requirements of the CAA, specifically, with the 
requirement that SIPs contain the emission limits, schedules of 
compliance, and other measures that are necessary to make reasonable 
progress toward the national visibility goal. That is, approving 
Wyoming's removal of the SCR requirement would be inconsistent with the 
statutory requirement that Wyoming's SIP contain the measures necessary 
to make reasonable progress toward the national visibility goal. 
Furthermore, EPA cannot propose to approve Wyoming's plant-wide 
NO<INF>X</INF> and SO<INF>2</INF> emission limits while proposing to 
disapprove the elimination of the SCR requirements for Units 1 and 2, 
because such a partial approval would render the SIP more stringent 
than the State intended. Regardless, as discussed in section IV.C, the 
installation of SCR on Units 1 and 2 is estimated to reduce 
NO<INF>X</INF> by at least 3,000 tons per year (tpy) based on current 
utilization. EPA believes it is reasonable to conclude that the plant-
wide NO<INF>X</INF> and SO<INF>2</INF> emission limits that Wyoming has 
required in lieu of the existing control requirements would not provide 
similar or greater emissions reductions or visibility improvement 
compared to two additional SCRs, as claimed by the State.

II. Background

A. Requirements of the Clean Air Act and 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

[[Page 2573]]

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.'' \6\
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    \6\ 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, 
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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    EPA promulgated a rule to address regional haze on July 1, 1999.\7\ 
The Regional Haze Rule revised the existing visibility regulations \8\ 
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 EPA's visibility protection regulations at 40 
CFR 51.300 through 40 CFR 51.309.\9\
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    \7\ 64 FR 35714, 35714 (July 1, 1999) (codified at 40 CFR part 
51, subpart P).
    \8\ 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).
    \9\ EPA revised the Regional Haze Rule on January 10, 2017. 82 
FR 3078 (January 10, 2017). Under the revised Regional Haze Rule, 
the requirements in 40 CFR 51.308(d) and (e) apply to first 
implementation period SIP submissions and 40 CFR 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.\10\ 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 EPA 
for approval.\11\ Once approved, a SIP is enforceable by EPA and 
citizens under the CAA; that is, the SIP is federally enforceable.
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    \10\ See 42 U.S.C. 7410(a), 7491, and 7492; CAA sections 110(a), 
169A, and 169B.
    \11\ 42 U.S.C. 7491(b)(2); 7410.
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B. Best Available Retrofit Technology

    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 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 EPA, in the case of a Federal implementation plan 
(FIP)) are directed to make BART determinations for such ``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.\12\ 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.\13\
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    \12\ 40 CFR 51.308(e). EPA designed the Guidelines for BART 
Determinations Under the Regional Haze Rule (Guidelines) ``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.'' 40 CFR part 51, 
appendix Y, 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'').
    \13\ 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 visibility in 
the 16 Class I areas on the Colorado Plateau.\14\
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    \14\ The Colorado Plateau is a high, semi-arid tableland in 
southeast Utah, northern Arizona, northwest New Mexico, and western 
Colorado. The 16 mandatory Class I areas are the 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 toward 
the national visibility goal for those 16 Class I areas, the GCVTC 
submitted a program to EPA, known as the Western SO<INF>2</INF> 
Backstop Trading Program, containing annual SO<INF>2</INF> emissions 
reduction milestones and detailed provisions for a backstop trading 
program to be implemented automatically if states' measures fail to 
achieve the SO<INF>2</INF> milestones. EPA approved the Backstop 
Trading Program as a BART alternative for SO<INF>2</INF> emissions.\15\ 
Transport Region States' SIPs must also contain BART requirements for 
stationary-source emissions of NO<INF>X</INF> and particulate 
matter.\16\
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    \15\ 64 FR 35714 (July 1, 1999); 68 FR 33764 (June 5, 2003).
    \16\ 40 CFR 51.309(d)(4)(vi).
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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. . . .'' \17\ The 
long-term strategy must address regional haze visibility impairment for 
each mandatory Class I area within the state and 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.\18\ The reasonable progress goals, in turn, 
are calculated for each Class I area based on the control measures 
states have selected for sources by applying 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.'' \19\ That is, states 
consider the four reasonable progress factors, and certain other 
factors listed in Sec.  51.308(d)(3) of the Regional Haze Rule, to 
determine what controls must be included in the long-term strategy. 
Those controls are represented in the long-term strategy, i.e., the 
SIP, as emission limits, schedules of compliance, and other measures. 
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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    \17\ 42 U.S.C. 7491(b)(2)(B).
    \18\ See 42 U.S.C. 7491(b)(2); 40 CFR 51.308(d)(3).
    \19\ 42 U.S.C. 7491(g)(1); 40 CFR 51.308(d)(1)(i)(A).
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    Unlike BART determinations, which are required only for the first 
regional haze planning period SIPs,\20\ states are

[[Page 2574]]

required to submit updates to their long-term strategies, including new 
reasonable progress analyses and reasonable progress goals, in the form 
of SIP revisions on July 31, 2021, and at specific intervals 
thereafter.\21\ In addition, each state must periodically submit a 
report to EPA at five-year intervals beginning five years after the 
submission of the initial regional haze SIP, evaluating the state's 
progress toward meeting the reasonable progress goals for each Class I 
area within the state.\22\
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    \20\ Under the Regional Haze Rule, SIPs are due for each 
regional haze planning period, or implementation period. The terms 
``planning period'' and ``implementation period'' are used 
interchangeably in this document.
    \21\ 40 CFR 51.308(f). The 2021 deadline was originally in 2018; 
EPA revised this deadline in 2017. 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).
    \22\ 40 CFR 51.308(g); 51.309(d)(10).
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    By meeting all the requirements of 40 CFR 51.309, including but not 
limited to the section 309-specific BART requirements, a Transport 
Region State can be deemed to be making reasonable progress toward the 
national goal for the first implementation period for the 16 Class I 
areas on the Colorado Plateau.\23\ For stationary sources, the section 
309 requirements include any necessary long-term strategies for 
reasonable progress for particulate matter (PM) and NO<INF>X</INF> 
emissions.\24\ Additionally, the State of Wyoming includes several non-
Colorado Plateau Class I areas, and thus was also required to submit a 
long-term strategy for those Class I areas.\25\
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    \23\ 40 CFR 51.309(a).
    \24\ 40 CFR 51.309(d)(4)(vii).
    \25\ 79 FR 5199.
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D. Consultation With Federal Land Managers

    The Regional Haze Rule requires that a state consult with Federal 
Land Managers (FLMs) before adopting and submitting a required SIP 
submittal or revision. Further, a state must include a summary of the 
FLMs' conclusions and recommendations in its notice to the public,\26\ 
as well as include in its submission to EPA a description of how it 
addressed any comments provided by the FLMs.\27\
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    \26\ 42 U.S.C. 7491(d).
    \27\ 40 CFR 51.308(i).
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III. Wyoming's Regional Haze SIP Revisions

A. Background

    The Jim Bridger power plant is 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. 
Wyoming determined that all four units are subject to BART.\28\
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    \28\ 77 FR 33022, 33030, 33035 (June 4, 2012).
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    Wyoming submitted a SIP on January 12, 2011, that addressed 
regional haze requirements under 40 CFR 51.309 for the first regional 
haze planning period. The State's regional haze SIP determined that 
NO<INF>X</INF> BART for Jim Bridger Units 1-4 was new LNB/SOFA. 
Compliance with the BART emission limits was required by March 4, 2019, 
for all four Jim Bridger units.\29\ The State also determined that 
emission limits consistent with the installation of SCR were necessary 
to satisfy the reasonable progress (not BART) requirements. Wyoming's 
SIP required compliance with these emission limits by December 31, 
2022, December 31, 2021, December 31, 2015, and December 31, 2016, for 
Units 1-4, respectively.\30\ The State indicated that the delayed 
timeline for installing SCR was based on the large number of retrofits 
that PacifiCorp was undertaking or helping to finance at power plants 
in Wyoming, Utah, Colorado, and Arizona.\31\
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    \29\ 79 FR 5221. Installation of new LNB with SOFA (LNB/SOFA) 
corresponds to a NO<INF>X</INF> emission limit of 0.26 lb/MMBtu (30-
day rolling average).
    \30\ Id. Installation and operation of SCR corresponds to a 
NO<INF>X</INF> emission limit of 0.07 lb/MMBtu (30-day rolling 
average).
    \31\ 77 FR 33053; see also State of Wyoming, ``Addressing 
Regional Haze Visibility Protection For The Mandatory Federal Class 
I Areas Required Under 40 CFR 51.309,'' January 7, 2011, at 102.
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    In June 2012, we proposed to find the State's BART determination 
for Jim Bridger Units 1 and 2 unreasonable. We explained that the cost-
effectiveness values for LNB/SOFA + SCR were reasonable and within the 
range that Wyoming had determined to be reasonable for other BART 
sources. We further explained that the associated visibility 
improvement and NO<INF>X</INF> emissions reductions were significant. 
Because the State's compliance date for installing SCR was beyond the 
five years allowed by the statute for BART sources, we proposed to 
disapprove the State's BART determination and proposed a FIP requiring 
a NO<INF>X</INF> emission limit consistent with the installation of SCR 
with a compliance deadline of no later than five years after EPA took 
final action.\32\
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    \32\ 77 FR 33053.
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    Alternatively, EPA proposed to conclude that while BART for all 
four Jim Bridger units was LNB/SOFA + SCR when the units were 
considered individually, i.e., without regard to other units in the 
PacifiCorp system, when considering all PacifiCorp's units with their 
additional retrofit obligations, BART was LNB/SOFA + SCR on Units 3 and 
4 and LNB + OFA on Units 1 and 2. EPA explained that, based on claims 
by the State and PacifiCorp, costs, considered broadly across all four 
units as well as for units in other states, could be unreasonable for 
PacifiCorp to incur within five years of EPA's final action. EPA then 
proposed in the alternative to approve Wyoming's BART and reasonable 
progress determinations for Units 1 and 2, the latter of which would 
require an SCR emission limit by December 31, 2021, for Unit 2, and 
December 31, 2022, for Unit 1. EPA noted that the Agency believed it 
``may be reasonable and feasible for [SCR] to be completed somewhat 
earlier'' but that, given the context, it ``may be appropriate to give 
considerable deference to the State's conclusions about what controls 
are reasonable and when they should be implemented.'' \33\
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    \33\ 77 FR 33054.
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    In 2013, EPA issued another proposal after the Agency conducted its 
own cost analyses and visibility modeling. As in 2012, EPA proposed two 
options in the alternative. In proposing to approve the State's BART 
and reasonable progress determinations for Jim Bridger Units 1 and 2, 
EPA again cited the fact that PacifiCorp may be required to install 
several additional retrofits at units in Wyoming and in other states 
and proposed to give deference to the State under the 
circumstances.\34\
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    \34\ 78 FR 34738, 34755-56 (June 10, 2013). However, of the 
twenty retrofit actions referenced in EPA's 2013 proposal, 
PacifiCorp has installed only two SCRs in Wyoming and three SCRs and 
one SNCR in Colorado to date.
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    In the alternative, EPA again proposed in 2013 to determine that 
BART for Jim Bridger Units 1 and 2 is LNB/SOFA + SCR and is required 
within five years of EPA's final action. EPA explained that the cost-
effectiveness values for installing SCR were reasonable and the 
visibility improvement at the most impacted Class I area was 
significant. EPA further explained that the cost estimates were within 
the range that Wyoming in its SIP and EPA in other SIP and FIP actions 
have considered reasonable in the BART context.\35\
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    \35\ 78 FR 34780.
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    After considering comments received on the 2012 and 2013 proposals, 
in the 2014 final rule, EPA finalized approval of Wyoming's 
determination that BART for Jim Bridger Units 1 and 2 was LNB/SOFA and 
that SCR should be required for reasonable progress as part of the 
State's long-term strategy by 2021 and 2022. EPA explained that the 
updated source-wide visibility improvement associated with the 
installation of LNB/SOFA + SCR would be significant (1.25-

[[Page 2575]]

1.5 deciviews) with unit-specific visibility benefits for Units 1 and 2 
at 0.27-0.37 deciviews at the most impacted Class I area (Bridger), 
respectively. We explained that ``[t]he fact that Jim Bridger Station 
affects a number of other Class I areas [(in addition to Bridger)], 
which would also see appreciable visibility improvement with the 
installation of LNB/SOFA + SCR, also weighs in favor of selecting this 
option as BART.'' \36\ We also found that the updated average cost-
effectiveness of LNB/SOFA + SCR at $2,635 and $3,403/ton for Units 1 
and 2, respectively, was in line with what we had found to be 
acceptable in other determinations,\37\ in addition to finding that the 
incremental cost-effectiveness of $7,447 and $8,968/ton for Units 1 and 
2, respectively, was on the high end of what we had found to be 
reasonable in other determinations.\38\ However, EPA ultimately 
concluded that, ``while we believe that these costs and visibility 
improvements could potentially justify LNB/SOFA + SCR as BART, because 
this is a close call and because the State has chosen to require SCR as 
a reasonable progress control, we believe deference to the State is 
appropriate in this instance.'' \39\ We thus finalized the State's 
determination to require LNB/SOFA as BART controls with a corresponding 
emission limit of 0.26 lb/MMBtu by March 4, 2019, for Jim Bridger Units 
1 and 2, and the State's determination to require SCR as part of the 
State's long-term strategy necessary to achieve reasonable progress 
with a corresponding emission limit of 0.07 lb/MMBtu (30-day rolling 
average) by 2022 and 2021 for Jim Bridger Units 1 and 2, 
respectively.\40\
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    \36\ 79 FR 5048.
    \37\ 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 Table 5 and 6 at 79 FR 
5040. Note that for Jim Bridger Units 3 and 4, we disagreed with 
Wyoming's conclusion that BART was not LNB/SOFA + SCR, but we 
nonetheless approved 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, because the 
compliance deadlines for SCR were all within the statutory timeframe 
for BART. 77 FR 33035-36; 79 FR 5046, 5221.
    \38\ 79 FR 5048.
    \39\ Id.
    \40\ 79 FR 5048-49.
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B. May 14, 2020 Submittal

    Notwithstanding the State's 2011 determination to require the 
installation of SCR as being necessary for reasonable progress in the 
State's long-term strategy for Jim Bridger 1 and 2 in 2021 and 2022, 
and the deference EPA afforded the State's determination in the 2014 
final rule (instead of requiring SCR as BART controls within five years 
of EPA's action), on May 14, 2020, Wyoming submitted a SIP revision for 
the purpose of amending the State's regional haze SIP and removing the 
SCR requirement for Jim Bridger Units 1 and 2.\41\ Wyoming stated that 
``[d]ue to the significant costs of installing SCR on Units 1 and 2, 
and the potential impact of those costs to PacifiCorp's customers, 
PacifiCorp reassessed its compliance with the Regional Haze Rule and 
developed an alternative regional haze compliance strategy . . . .'' 
\42\
---------------------------------------------------------------------------

    \41\ 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.
    \42\ Wyoming 2020 SIP Revision at 3.
---------------------------------------------------------------------------

    The State's 2020 SIP revision contains a source-specific, 
NO<INF>X</INF>-only reasonable progress analysis and determination for 
Jim Bridger Units 1 and 2, as well as plant-wide annual and monthly 
NO<INF>X</INF> and SO<INF>2</INF> emission limits for Jim Bridger Units 
1-4. Specifically, the amendments provide a source-specific reasonable 
progress four-factor analysis and consideration of visibility benefits 
for Jim Bridger Units 1 and 2 to demonstrate that the current LNB/SOFA 
NO<INF>X</INF> BART controls also satisfy the reasonable progress 
requirements for those units for the first planning period. The SIP 
revision thereby would remove the existing reasonable progress 
requirement for Jim Bridger Units 1 and 2 to comply with emission 
limits of 0.07 lb/MMBtu in 2021 and 2022 (Table 1).

                  Table 1--Existing and Proposed NOX Emission Limits for Jim Bridger Units 1-4
----------------------------------------------------------------------------------------------------------------
                                                                               Existing NOX       Proposed NOX
                                                         Existing NOX BART      reasonable         reasonable
                                                           emission limit   progress emission  progress emission
                          Unit                            (30-day rolling     limit (30-day      limit (30-day
                                                            average; lb/     rolling average;   rolling average;
                                                             MMBtu) \1\       lb/MMBtu) \2\        lb/MMBtu)
----------------------------------------------------------------------------------------------------------------
1......................................................               0.26               0.07               0.26
2......................................................               0.26               0.07               0.26
3......................................................               0.26               0.07            \3\ N/A
4......................................................               0.26               0.07            \3\ N/A
----------------------------------------------------------------------------------------------------------------
\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\ No change to existing NOX reasonable progress emission limit of 0.07 lb/MMBtu (30-day rolling average).


[[Page 2576]]

    In addition, Wyoming's 2020 SIP revision would add federally 
enforceable month-by-month plant-wide NO<INF>X</INF> and SO<INF>2</INF> 
emission limits across all four Jim Bridger units, as well as an 
enforceable annual plant-wide NO<INF>X</INF> and SO<INF>2</INF> 
emissions cap of 17,500 tpy, effective January 1, 2022 (Table 2). The 
plant-wide monthly and annual emission limits for Jim Bridger Units 1-4 
are already State-enforceable through Wyoming air quality permit 
#P0025809. The final permit was issued on May 5, 2020.\43\
---------------------------------------------------------------------------

    \43\ 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 Plant-Wide Block 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
               Month                  limit (monthly     limit (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
------------------------------------------------------------------------

C. Summary of Wyoming's Reasonable Progress Reassessment

    Pursuant to CAA section 169A(g)(1) and 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:
    <bullet> Costs of Compliance;
    <bullet> Time Necessary for Compliance;
    <bullet> Energy and Non-Air Quality Environmental Impacts of 
Compliance; and
    <bullet> Remaining Useful Life of Any Potentially Affected Sources.
    In order to conduct a source-specific reasonable progress 
assessment for Jim Bridger Units 1 and 2, the State took into 
consideration the four required factors and also included visibility 
improvement as an additional factor in its reasonable progress 
analysis.\44\ Wyoming relied on information provided by PacifiCorp and 
EPA for evaluating potential reasonable progress NO<INF>X</INF> 
emissions controls--LNB/SOFA, LNB/SOFA + selective non-catalytic 
reduction (SNCR), and LNB/SOFA + SCR--at Jim Bridger.\45\
---------------------------------------------------------------------------

    \44\ The visibility benefit of an emissions reduction measure is 
not listed as a required factor, but neither the CAA nor the 
Regional Haze Rule prohibits a state from considering visibility 
benefits when it determines what emissions control measures are 
required for a source to make reasonable progress at a Class I area. 
Therefore, a state may consider the visibility benefits of potential 
control measures when determining what is necessary to make 
reasonable progress.
    \45\ Wyoming 2020 SIP Revision at 3; see also PacifiCorp, Jim 
Bridger Power Plant Reasonable Progress Determination to Support 
PacifiCorp's Reasonable Progress Reassessment (PacifiCorp 
Reassessment), February 2019.
---------------------------------------------------------------------------

1. Costs of Compliance
    For the source-specific reasonable progress analysis associated 
with this action, Wyoming relied on cost information provided by 
PacifiCorp. PacifiCorp used NO<INF>X</INF> emission rates for LNB/SOFA 
of 0.187 lb/MMBtu and 0.192 lb/MMBtu (annual average) reflective of the 
actual emissions rate (2013-2015) for Units 1 and 2, respectively. The 
anticipated NO<INF>X</INF> emission rate for LNB/SOFA + SNCR was 
assumed to be 0.15 lb/MMBtu (annual) for both Units 1 and 2. The 
NO<INF>X</INF> emission rate for LNB/SOFA + SCR was assumed to be 0.05 
lb/MMBtu (annual), which corresponds to the 0.07 lb/MMBtu LNB/SOFA + 
SCR NO<INF>X</INF> 30-day rolling average emission limits for Units 1 
and 2 that EPA approved in the 2014 final rule.
    Wyoming's source-specific reasonable progress analysis for Units 1 
and 2 based capital costs and annual operating and maintenance (O&M) 
costs on the actual costs incurred to install and operate SCR 
technology on Jim Bridger Units 3 and 4, as well as the actual costs to 
install LNB/SOFA on Units 1 and 2 (Table 3). Capital costs for SNCR 
technology were estimated based on recent similarly sized projects 
(Table 3).\46\
---------------------------------------------------------------------------

    \46\ Wyoming 2020 SIP Revision, PacifiCorp, Corrected JB RP 
Reassessment NO<INF>X</INF> Comparison Tables, October 6, 2020.

Table 3--PacifiCorp's Total Capital and O&M Costs for the Jim Bridger Units 1 and 2 Reasonable Progress Analysis
----------------------------------------------------------------------------------------------------------------
                                                   Total installed capital costs     Total O&M costs ($/year)
                                                                ($)              -------------------------------
             NOX control technology              --------------------------------
                                                      Unit 1          Unit 2          Unit 1          Unit 2
----------------------------------------------------------------------------------------------------------------
LNB/SOFA........................................      $8,410,000      $7,986,000  ..............  ..............
SNCR............................................      15,538,000      15,538,000       2,954,000       3,158,000
SCR.............................................     140,428,000     140,428,000       2,580,000       2,527,000
----------------------------------------------------------------------------------------------------------------


[[Page 2577]]

    PacifiCorp annualized capital costs using the capital recovery 
factor (CRF) approach described in EPA's Control Cost Manual using 20-
year and 30-year amortization periods for SNCR and SCR, 
respectively.\47\ Total annual costs were calculated as the sum of the 
annualized capital costs and total O&M costs. The cost-effectiveness of 
each NO<INF>X</INF> control technology was calculated on a dollar-per-
ton of pollutant removed basis by dividing the total annual costs by 
the reduction in annual NO<INF>X</INF> emissions associated with each 
NO<INF>X</INF> emissions control technology (i.e., LNB/SOFA, LNB/SOFA + 
SNCR, LNB/SOFA + SCR). Similarly, PacifiCorp calculated the incremental 
cost-effectiveness of each NO<INF>X</INF> control technology on a 
dollar-per-ton of pollutant removed basis by dividing the difference of 
the total annual costs (of one control technology compared to that of 
the next most stringent control technology) by the difference in the 
reduction in annual NO<INF>X</INF> emissions (of the two control 
technologies).
---------------------------------------------------------------------------

    \47\ EPA, ``Control Cost Manual,'' Section 4, Chapter 1, April 
25, 2019, page 1-53-54, and 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 
December 2021).
---------------------------------------------------------------------------

    The summary of cost-effectiveness figures for Wyoming's reasonable 
progress analysis for Jim Bridger Units 1 and 2 is shown in Table 4. 
Baseline NO<INF>X</INF> emissions (2001-2003) are 8,432 tpy and 7,575 
tpy for Units 1 and 2, respectively.
---------------------------------------------------------------------------

    \48\ Wyoming 2020 SIP Revision, PacifiCorp, Corrected JB RP 
Reassessment NO<INF>X</INF> Comparison Tables, October 6, 2020.

        Table 4--Summary of Jim Bridger Units 1 and 2 NOX Revised Reasonable Progress Cost Analysis \48\
----------------------------------------------------------------------------------------------------------------
                                NOX emissions                                                      Incremental
                                  rate (lb/       Emissions     Annualized cost   Average cost-       cost-
    NOX control technology     MMBtu; annual)  reduction (tpy)      ($/year)      effectiveness   effectiveness
                                                                                     ($/ton)         ($/ton)
----------------------------------------------------------------------------------------------------------------
                                                     Unit 1
----------------------------------------------------------------------------------------------------------------
LNB/SOFA.....................       \1\ 0.187  4,414..........  $794,000.......            $180  ...............
LNB/SOFA + SNCR..............        \2\ 0.15  5,209..........  5,215,000......           1,001  5,560
LNB/SOFA + SCR...............            0.05  7,358..........  14,692,000.....           1,997  4,410
----------------------------------------------------------------------------------------------------------------
                                                     Unit 2
----------------------------------------------------------------------------------------------------------------
LNB/SOFA.....................       \1\ 0.192  3,649..........  754,000........             207  ...............
LNB/SOFA + SNCR..............        \2\ 0.15  4,508..........  5,379,000......           1,193  5,385
LNB/SOFA + SCR...............            0.05  6,552..........  14,599,000.....           2,228  4,510
----------------------------------------------------------------------------------------------------------------
\1\ lb/MMBtu, annual average.
\2\ lb/MMBtu, annual. The controlled NOX emission rate with SNCR was assumed to be 0.15 lb./MMBtu, which
  corresponds with a reduction of approximately 20 percent.

    Wyoming also summarized the total estimated capital costs and 
annual costs combined for Units 1 and 2 for the installation of SCR and 
SNCR, in addition to the LNB/SOFA NO<INF>X</INF> emissions controls 
already installed, for the revised reasonable progress analysis (Table 
5).
---------------------------------------------------------------------------

    \49\ Wyoming 2020 SIP Revision at 5.

 Table 5--Total Capital and Annual Costs for Jim Bridger Units 1 and 2 Revised Reasonable Progress Analysis \49\
----------------------------------------------------------------------------------------------------------------
                                                                      Control      Capital costs   Annual costs
                     NOX control technology                       efficiency (%)        ($)          ($/year)
----------------------------------------------------------------------------------------------------------------
LNB/SOFA........................................................              53     $16,396,000      $1,548,000
LNB/SOFA + SNCR.................................................              63      47,472,000      10,594,000
LNB/SOFA + SCR..................................................              87     297,252,000      29,291,000
----------------------------------------------------------------------------------------------------------------

    Although Jim Bridger Units 3 and 4 are not included in the 
reasonable progress analysis, Wyoming noted that the total capital cost 
for LNB/SOFA + SCR installation on Units 3 and 4, which are already 
installed, was $310,959,000. Ultimately, Wyoming concluded that the 
installation of SCR on Jim Bridger Units 1 and 2 would cost ``hundreds 
of millions more'' than the costs already incurred for LNB/SOFA 
NO<INF>X</INF> emissions controls while SNCR would cost ``tens of 
millions more'' than the costs already incurred for LNB/SOFA 
NO<INF>X</INF> emissions controls.\50\
---------------------------------------------------------------------------

    \50\ Id.
---------------------------------------------------------------------------

2. Time Necessary for Compliance
    As stated previously, the SIP approved by 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. Wyoming stated in the 2020 
SIP revision that if SNCR installation was required, the compliance 
timelines would match the SCR timeline. The current LNB/SOFA 
NO<INF>X</INF> emissions controls were installed in 2010 and 2005 for 
Units 1 and 2, respectively.\51\
---------------------------------------------------------------------------

    \51\ Id. at 6.
---------------------------------------------------------------------------

3. Energy and Non-Air Quality Environmental Impacts of Compliance
    The State identified that SCR control technology would periodically 
produce solid waste when the catalyst is changed. Additionally, Wyoming 
stated that SCR control technology would require the storage and use of 
ammonia, while SNCR would require the storage

[[Page 2578]]

and use of urea. With respect to energy use, the State estimated that 
SNCR would require 6 times the energy required by the current 
NO<INF>X</INF> control technology (LNB/SOFA), and SCR would require 150 
times the energy required by LNB/SOFA. Wyoming further stated that SCR 
would require the use of an additional 10.4 megawatts of energy. 
Wyoming did not anticipate any additional negative non-air 
environmental impacts associated with the current LNB/SOFA 
NO<INF>X</INF> emissions controls.\52\
---------------------------------------------------------------------------

    \52\ Id. at 6.
---------------------------------------------------------------------------

4. Remaining Useful Life
    For this evaluation, Wyoming stated that the expected life of the 
source is less than the expected life of the emissions control 
technology, which is 30 years for SCR and 20 years for SNCR. However, 
Wyoming did not provide an enforceable shutdown date that would ensure 
that the expected life of the source would in fact be reduced.\53\ 
Therefore, notwithstanding the State's expectation of a shortened 
remaining useful life for the source, it used the full 30-year and 20-
year periods for SCR and SNCR, respectively, in its analyses.
---------------------------------------------------------------------------

    \53\ Id. at 4.
---------------------------------------------------------------------------

5. Visibility Improvement
    Although visibility improvement is not one of the four statutory 
factors for reasonable progress, Wyoming elected to include visibility 
improvement in the reasonable progress analysis for Jim Bridger Units 1 
and 2. Wyoming did not complete new visibility modeling for the 
reasonable progress analysis and determination. Instead, the State 
relied upon EPA's CALPUFF modeling results contained in the 2014 final 
rule to assess the visibility impacts of the NO<INF>X</INF> emissions 
control technologies evaluated, i.e., for LNB/SOFA, LNB/SOFA + SNCR, 
LNB/SOFA + SCR.\54\ In our 2014 final rule, we evaluated the CALPUFF 
visibility modeling of the Jim Bridger power plant for the most 
impacted Class I area, Bridger Wilderness (Table 6).\55\
---------------------------------------------------------------------------

    \54\ See id. at 7. In the 2014 final rule, EPA addressed 
comments on the visibility improvement modeling by developing a new 
protocol that makes several improvements in the modeling, including 
the latest regulatory version of the CALPUFF model at the time of 
the rule (version 5.8), the use of an improved method to assess the 
effects of pollutants on light scattering and visibility impairment 
(Method 8), the use of background ammonia concentrations based on 
monitoring data and regulatory default concentrations for the area, 
and the use of an ammonia-limiting correction to treat sources with 
multiple units. We used two sets of background ammonia 
concentrations based on representative monthly varying ammonia 
concentrations and default concentrations for forested areas.
    \55\ 79 FR 5048.

          Table 6--Summary of Jim Bridger Power Plant NOX Visibility Analysis in EPA's 2014 Final Rule
----------------------------------------------------------------------------------------------------------------
                                                         Visibility Improvement (deciviews) \1\ (modeled results
                                                             using an ammonia background based on a monitored
                                                           monthly varying concentration/modeled results using
                      Jim Bridger                             IWAQM default 0.5 ppb background ammonia) \3\
                                                        --------------------------------------------------------
                                                              LNB/SOFA       LNB/SOFA + SNCR     LNB/SOFA + SCR
----------------------------------------------------------------------------------------------------------------
Unit 1.................................................          0.17/0.23          0.20/0.27          0.27/0.37
Unit 2.................................................          0.16/0.21          0.19/0.25          0.27/0.36
Unit 3.................................................          0.14/0.19          0.17/0.23          0.26/0.35
Unit 4.................................................          0.25/0.23          0.30/0.28          0.45/0.42
                                                        --------------------------------------------------------
    Total \2\..........................................          0.72/0.86          0.86/1.03           1.25/1.5
----------------------------------------------------------------------------------------------------------------
\1\ For most impacted Class I area, Bridger Wilderness.
\2\ The total visibility improvement was estimated as the sum of the visibility improvement from each unit.
\3\ EPA, Air Quality Modeling Protocol; Wyoming Regional Haze Implementation Plan, January 2014.

    The State noted that EPA determined in 2014 that the unit-specific 
visibility benefits for LNB/SOFA + SCR installation on Units 1 and 2 
were ``modest'' at 0.27 to 0.37 deciviews. In addition, the State noted 
that the incremental visibility improvement, as determined by EPA, of 
LNB/SOFA + SCR over LNB/SOFA, was 0.10 to 0.14 deciviews for Unit 1 and 
0.11 to 0.15 deciviews for Unit 2. The State further noted that 
incremental improvement of LNB/SOFA + SNCR over LNB/SOFA was smaller at 
between 0.03-0.04 deciviews for both Units 1 and 2.\56\
---------------------------------------------------------------------------

    \56\ Wyoming 2020 SIP Revision at 7.
---------------------------------------------------------------------------

    In addition to comparing the visibility impacts associated with 
each NO<INF>X</INF> emissions control technology, Wyoming also pointed 
to PacifiCorp's estimated NO<INF>X</INF> emissions reductions. The 
State asserted that the current LNB/SOFA NO<INF>X</INF> emissions 
controls already have reduced NO<INF>X</INF> emissions from the 2001-
2003 baseline by a combined 8,063 tpy for Units 1 and 2. The 
installation of SCR would reduce NO<INF>X</INF> emissions from the 
2001-2003 baseline by an additional 5,848 tpy (Units 1 and 2 combined), 
while the installation of SNCR would reduce NO<INF>X</INF> emissions 
from the baseline by an additional 1,655 tpy.\57\
---------------------------------------------------------------------------

    \57\ Id.
---------------------------------------------------------------------------

    According to the State, in spite of the additional NO<INF>X</INF> 
emissions reductions achievable through each NO<INF>X</INF> control 
technology, EPA's 2014 modeling demonstrates that the installation of 
SCR on Units 1 and 2 would result in only modest incremental visibility 
benefits of 0.10-0.15 deciviews (per unit) when compared to current 
LNB/SOFA NO<INF>X</INF> emissions controls on Units 1 and 2. The State 
concluded that these visibility improvements are not significant enough 
to outweigh the substantial cost of installing SCR. Instead, Wyoming 
concluded that relying on the current NO<INF>X</INF> emissions controls 
(LNB/SOFA) is the reasonable choice for Jim Bridger Units 1 and 2.\58\
---------------------------------------------------------------------------

    \58\ Id. at 7-8.
---------------------------------------------------------------------------

6. Reasonable Progress Demonstration

[[Page 2579]]

    After considering each of the four reasonable progress factors, 
states must demonstrate how those factors, and visibility improvement 
if included in the analysis, were taken into consideration in making a 
reasonable progress determination.\59\ Thus, after consideration of the 
four factors, along with an evaluation of the modeled visibility 
impacts at the most impacted Class I area (Bridger Wilderness), Wyoming 
determined that no additional controls beyond BART are necessary for 
Jim Bridger Units 1 and 2 under the reasonable progress provisions for 
the first regional haze planning period. Wyoming determined that, 
``[w]hile SCR installation on Units 1 & 2 could be expected to be more 
efficient in controlling NO<INF>X</INF> emission than either SNCR 
installation or relying on Current Unit 1-2 NO<INF>X</INF> Controls 
[(LNB/SOFA)], the estimated capital costs, annual costs, and cost-
effectiveness are far higher for SCR and SNCR, compared with little 
modeled visibility benefit.'' \60\ In addition, the State explained 
that SCR will produce solid waste every time the catalyst must be 
replaced and will have higher electricity requirements. The State 
further explained that the current NO<INF>X</INF> controls are already 
in use and do not require additional time for compliance.\61\
---------------------------------------------------------------------------

    \59\ 40 CFR 51.308(d)(1)(i)(A).
    \60\ Wyoming 2020 SIP Revision at 7.
    \61\ Id.
---------------------------------------------------------------------------

    Wyoming stated that its reasonable progress determination for Jim 
Bridger Units 1 and 2 is consistent with several similar EPA decisions 
where EPA rejected SNCR and SCR because the cost-effectiveness values 
associated with the control measures were significantly higher and/or 
the NO<INF>X</INF> emissions reductions achieved were not that much 
more than combustion controls (LNB) alone.\62\ Furthermore, Wyoming 
stated that it considers the costs that PacifiCorp has already incurred 
on NO<INF>X</INF> emissions control technology at the Jim Bridger power 
plant and the associated improvement in visibility to be sufficient for 
reasonable progress.\63\
---------------------------------------------------------------------------

    \62\ Id. at 7, 8 (citing 77 FR 24794 (April 25, 2012), 77 FR 
11879 (February 28, 2012), 77 FR 18052 (March 26, 2012), 77 FR 23988 
(April 20, 2012), 83 FR 62204 (November 30, 2018), 80 FR 18944 
(April 8, 2015), 77 FR 21896 (April 12, 2012)).
    \63\ Id. at 7.
---------------------------------------------------------------------------

    In summary, Wyoming concluded that the reasonable progress analysis 
demonstrates that the current NO<INF>X</INF> emissions controls (LNB/
SOFA) on Units 1 and 2, including the current NO<INF>X</INF> emission 
limits of 0.26 lb/MMBtu (30-day rolling average), which apply to each 
unit, constitute NO<INF>X</INF> reasonable progress for Jim Bridger 
Units 1 and 2. Therefore, Wyoming's 2020 SIP revision would remove the 
emission limits of 0.07 lb/MMBtu (30-day rolling average) associated 
with the installation of SCR at Jim Bridger Units 1 and 2 as part of 
the State's long-term strategy to achieve reasonable progress at 
several Class I areas for the first planning period.\64\
---------------------------------------------------------------------------

    \64\ Id. at 8.
---------------------------------------------------------------------------

D. Summary of Wyoming's Plant-Wide Monthly and Annual NOX and SO2 
Emission Limits for Jim Bridger

    In addition to concluding that emission limits consistent with LNB/
SOFA are sufficient for reasonable progress for Jim Bridger Units 1 and 
2, the State asserted that PacifiCorp's plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits for Jim Bridger Units 
1-4 strengthen and support the reasonable progress determination for 
Jim Bridger Units 1 and 2. Specifically, the State quoted EPA's 2007 
Reasonable Progress Goals Guidance (2007 Guidance), which provides that 
States ``have flexibility in how to take into consideration [the] 
statutory factors and any other factors [the state has] determined to 
be relevant,'' \65\ in claiming that PacifiCorp's monthly plant-wide 
NO<INF>X</INF> and SO<INF>2</INF> emission limits (shown in Table 2) 
and the annual plant-wide NO<INF>X</INF> and SO<INF>2</INF> emissions 
cap of 17,500 tpy are relevant in Wyoming's revised reasonable progress 
analysis and determination. The State pointed to a number of factors to 
describe how the plant-wide monthly and annual NO<INF>X</INF> and 
SO<INF>2</INF> emission limits bolster the revised reasonable progress 
analysis. These include what the State asserted are greater modeled 
visibility improvement, lower costs, and fewer overall energy and 
environmental impacts than the installation of SCR and SNCR on Units 1 
and 2.\66\
---------------------------------------------------------------------------

    \65\ Wyoming 2020 SIP Revision at 8-9 (quoting EPA's ``Guidance 
for Setting Reasonable Progress Goals Under the Regional Haze 
Program,'' June 1, 2007 (2007 Guidance)).
    \66\ Wyoming 2020 SIP Revision at 8-12.
---------------------------------------------------------------------------

    Wyoming relied on CALPUFF visibility modeling conducted by 
PacifiCorp to evaluate visibility improvement associated with the 
plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits compared to LNB/SOFA + SCR and LNB/SOFA + SNCR.\67\ The 
CALPUFF modeling report used the following three metrics to evaluate 
the results:
---------------------------------------------------------------------------

    \67\ Wyoming chose the CALPUFF visibility model because it was 
the same model used to analyze the existing reasonable progress 
requirements (79 FR 5039). See Wyoming 2020 SIP Revision at 11.
---------------------------------------------------------------------------

    <bullet> The 98th percentile modeled delta-deciview, averaged over 
the 3 years modeled and applied to each Class I area individually;
    <bullet> The number of modeled days (summed over the 3 years 
modeled) with a plant-wide impact above 0.5 delta-deciview, applied to 
each Class I area individually; and
    <bullet> The number of modeled days (summed over the 3 years 
modeled) with a plant-wide impact above 1.0 delta-deciview, applied to 
each Class I area individually.
    Under all three metrics, Wyoming asserted that the updated CALPUFF 
modeling results demonstrate that the plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits resulted in greater 
visibility improvement than SCR and SNCR.\68\
---------------------------------------------------------------------------

    \68\ Id. at 11-12.
---------------------------------------------------------------------------

    With respect to the 98th percentile metric, the State asserted that 
the visibility impacts for the Jim Bridger power plant under the SCR, 
SNCR, and plant-wide monthly and annual NO<INF>X</INF> and 
SO<INF>2</INF> emission limits scenarios are 0.760, 0.930, and 0.653 
deciviews, respectively.\69\ Wyoming further asserted that the number 
of CALPUFF-modeled days resulting in a plant-wide visibility impact 
above 0.5 delta-deciviews over a three-year period under the SCR, SNCR, 
and plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits scenarios are 475, 597, and 371 days, respectively. 
Finally, with respect to the number of CALPUFF-modeled days resulting 
in a plant-wide visibility impact above 1.0 delta-deciview over a 
three-year period under the SCR, SNCR, and plant-wide monthly and 
annual NO<INF>X</INF> and SO<INF>2</INF> emission limits scenarios are 
127, 195, and 108 days, respectively, according to the State.\70\
---------------------------------------------------------------------------

    \69\ Averaged across all impacted Class I areas, including 
Bridger Wilderness, Fitzpatrick Wilderness, Grand Teton National 
Park, Mt. Zirkel Wilderness, Rocky Mountain National Park, Rawah 
Wilderness, Teton Wilderness, Washakie Wilderness, and Yellowstone 
National Park. PacifiCorp Reassessment at 15.
    \70\ Id. at 11-12.
---------------------------------------------------------------------------

    According to Wyoming, installation of SCR and SNCR on Units 1 and 2 
will result in the reduction of NO<INF>X</INF> emissions of 5,848 and 
1,655 tpy respectively, relative to ``current operating potential.'' 
``Current operating potential,'' as defined in PacifiCorp's technical 
analysis, is based on a combination of recent emission rates with 
plant-wide heat input (i.e., utilization) from the 2001-2003 
period.\71\ Implementation of the plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits will result in the 
reduction of NO<INF>X</INF> and SO<INF>2</INF>

[[Page 2580]]

emissions of 6,056 tpy relative to a baseline of 2001-2003 utilization. 
In addition to reductions in NO<INF>X</INF> and SO<INF>2</INF> 
emissions, Wyoming stated that the plant-wide emission limits will 
reduce all emissions from the Jim Bridger power plant, including PM, 
mercury (Hg), greenhouse gases (GHG), carbon monoxide (CO), carbon 
dioxide (CO<INF>2</INF>), and sulfuric acid 
(H<INF>2</INF>SO<INF>4</INF>), as well as reduce coal consumption, coal 
combustion residual production and disposal, and raw water 
consumption.\72\
---------------------------------------------------------------------------

    \71\ See PacifiCorp Reassessment, Attachment 1 at 21.
    \72\ Id. at 9-10.
---------------------------------------------------------------------------

    To compare cost-effectiveness estimates, the State relied on 
PacifiCorp's analysis using total tons of SO<INF>2</INF> and 
NO<INF>X</INF> reduced from ``current operating potential'' under the 
assumption that the pollutants would have equivalent visibility impacts 
(Table 7).

 Table 7--PacifiCorp's Summary of Jim Bridger Units 1-4, Cost Analysis for SCR, SNCR, and Plant-Wide Monthly and
                                       Annual NOX and SO2 Emission Limits
----------------------------------------------------------------------------------------------------------------
                                                                                                       Cost-
              Jim Bridger                  Control technology      Capital cost     Annualized     effectiveness
                                                                        ($)        cost ($/year)      ($/ton)
----------------------------------------------------------------------------------------------------------------
Units 1-2.............................  SCR.....................     280,856,000      27,743,000           4,744
Units 1-2.............................  SNCR....................      31,076,000       9,046,000           5,469
Units 1-4.............................  Monthly and Annual Plant-      4,659,000       2,115,000             349
                                         Wide Emission Limits.
----------------------------------------------------------------------------------------------------------------

    Wyoming also asserted that the plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits are more cost-
effective than SCR or SNCR. Furthermore, Wyoming claimed that even if 
all three emissions control measures are compared on a NO<INF>X</INF>-
only basis (excluding SO<INF>2</INF>), the plant-wide monthly and 
annual NO<INF>X</INF> and SO<INF>2</INF> emission limits remain the 
most cost-effective option.\73\
---------------------------------------------------------------------------

    \73\ Id. at 9-10.
---------------------------------------------------------------------------

    In addition to the asserted visibility and cost benefits associated 
with the plant-wide monthly and annual NO<INF>X</INF> and 
SO<INF>2</INF> emission limits, Wyoming compared the energy and non-air 
quality environmental impacts of compliance. First, Wyoming contended 
that, as compared to the use of SCR, the plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits would allow 
approximately 10.4 megawatts of electrical energy required by SCR for 
Units 1 and 2 to be instead directed to the electrical grid to power 
approximately 8,761 average homes. Second, Wyoming asserted that the 
installation of SCR controls on Units 1 and 2 would not restrict the 
capacity factor of these units (e.g., the annual heat output), so these 
units could operate with a potential average annual capacity factor of 
100 percent. In contrast, Wyoming explained that implementation of the 
plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits would limit the capacity of all four units and 
effectively limit annual boiler heat input, thereby also providing a 
reduction in the consumption of natural resources (i.e., water and 
coal). Third, Wyoming asserted that the installation of SCR at Units 1 
and 2 would result in additional storage and use of ammonia and create 
more coal combustion residuals. Likewise, the installation of SNCR on 
Units 1 and 2 would result in additional storage and use of urea and 
would also create more coal combustion residuals compared to the plant-
wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> emission 
limits. Finally, Wyoming asserted that the plant-wide monthly and 
annual NO<INF>X</INF> and SO<INF>2</INF> emission limits provide the 
entire facility the flexibility to ``load follow'' or accommodate 
intermittent influx of renewable energy into the western power grid, 
which has larger scale environmental impacts in Wyoming and across the 
West.\74\
---------------------------------------------------------------------------

    \74\ Id. at 10-11.
---------------------------------------------------------------------------

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

A. Basis for Proposed Disapproval

    Although states have discretion under the Regional Haze Rule to 
balance the four statutory factors in making control determinations for 
sources, their analyses must be both reasoned and moored to the 
statutory requirement to make reasonable progress toward the national 
visibility goal.\75\ The Regional Haze Rule provides that, ``in 
determining whether the State's goal for visibility improvement 
provides for reasonable progress toward natural visibility conditions, 
the Administrator will evaluate'' the state's demonstration under 40 
CFR 51.308(d)(1)(i) and (ii).\76\ Thus, our regulations and the CAA 
require that we review the reasonableness of the State's reasonable 
progress determination in light of the goal of achieving natural 
visibility conditions. This approach is also inherent in our role as 
the administrative agency empowered to review and approve SIPs. In this 
SIP review action, EPA is not only authorized, but required to exercise 
independent technical judgement in evaluating the adequacy of the 
State's regional haze SIP, including its reasonable progress 
determinations.\77\
---------------------------------------------------------------------------

    \75\ Cf. Arizona v. EPA, 815 F.3d 519, 531 (9th Cir. 2016) 
(While states have discretion to balance the five BART factors, they 
must also adhere to certain requirements when conducting BART 
analyses. EPA may not approve BART determinations that are based on 
analyses that are unreasoned or unmoored to the statutory 
provisions.) (citing N. Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 
2013)).
    \76\ 40 CFR 51.308(d)(1)(iii).
    \77\ 42 U.S.C. 7410(a)(2)(J), (l), (k)(3); 7491(a)(1), 
(b)(2)(B); Oklahoma v. EPA, 723 F.3d 1201 (10th Cir. 2013).
---------------------------------------------------------------------------

    For the reasons described in section IV.B. below, EPA proposes to 
disapprove Wyoming's regional haze SIP revision. Our proposed action is 
based on an evaluation of Wyoming's 2020 SIP revision under the 
regional haze requirements at 40 CFR 51.300-51.309 and CAA section 
169A. The revisions were also evaluated against the general SIP 
requirements contained in CAA section 110 and our regulations 
applicable to this action. Additionally, EPA is not reopening, and thus 
not accepting comment on, EPA's 2014 approval of Wyoming's BART 
determinations for Jim Bridger Units 1-4 or EPA's 2014 approval of the 
emission limits Wyoming required as reasonable progress controls for 
Jim Bridger Units 3 and 4. Any comments on these issues will be deemed 
beyond the scope of this action.

[[Page 2581]]

B. EPA's Proposed Disapproval of Wyoming's Reasonable Progress 
Determination for Jim Bridger Units 1 and 2

    We are proposing to disapprove Wyoming's regional haze SIP revision 
for the NO<INF>X</INF> reasonable progress determination for Jim 
Bridger Units 1 and 2.
    In our analysis of the Wyoming 2020 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). Under this requirement, a state must 
consider the following four factors and include a demonstration of how 
they were taken into consideration in making a reasonable progress 
determination:
    <bullet> Costs of Compliance;
    <bullet> Time Necessary for Compliance;
    <bullet> Energy and Non-Air Quality Environmental Impacts of 
Compliance; and
    <bullet> Remaining Useful Life of Any Potentially Affected Sources.
    The State has discretion to reasonably weigh these four factors, 
along with visibility improvement if it so chooses, to determine what 
controls are necessary to include in the long-term strategy for a 
specific source. States exercise this discretion within the context of 
the statutory requirement to make reasonable progress toward the 
national visibility goal.\78\
---------------------------------------------------------------------------

    \78\ 42 U.S.C. 7491(a)(1), (b)(2)(B); 40 CFR 51.308(d)(1)(iii).
---------------------------------------------------------------------------

1. Basis of Our Proposed Disapproval
    We are proposing to find that Wyoming's 2020 SIP revision does not 
provide a reasonable basis for reversing the State's 2011 determination 
of what reasonable progress controls are necessary for Jim Bridger 
Units 1 and 2 for the first planning period. Our proposed disapproval 
is based on the following: (1) The reasonable cost-effectiveness of the 
existing control requirements for Jim Bridger Units 1 and 2 (emission 
limits consistent with the installation of SCR); (2) the appreciable 
visibility improvement estimated to result from compliance with the 
existing reasonable progress control requirements; and (3) the fact 
that the State previously determined that the costs of those control 
requirements were reasonable and that they are necessary to satisfy the 
statutory requirements, and has not provided any new information that 
would support a revised determination that the existing control 
requirements are now unreasonable. Because the State has not provided 
adequate justification for reversing its 2011 determination, removing 
the existing emission limits reflecting LNB/SOFA + SCR from the SIP 
would be inconsistent with the requirement that SIPs contain the 
measures necessary to make reasonable progress toward the national 
visibility goal. We therefore propose to disapprove the State's 2020 
SIP revision.
    As an initial matter, we propose to find that the State reasonably 
characterized the four factors required in a reasonable progress 
analysis, including the costs of compliance, the time necessary for 
compliance, energy and non-air quality environmental impacts of 
compliance, and the remaining useful life of any potentially affected 
sources. In addition, we agree with the State that, although visibility 
improvement is not one of the four factors required by CAA section 
169A(g)(1) and 40 CFR 51.308(d)(1)(i)(A), visibility improvement (along 
with the statutory factors) can be considered to determine what control 
measures are necessary to make reasonable progress.\79\
---------------------------------------------------------------------------

    \79\ See 77 FR 57864, 57899 (September 18, 2012), 79 FR 9318, 
9353-54 (February 18, 2014), 81 FR 296, 309-310 (January 5, 2016). 
See also 2007 Guidance at page 5-1.
---------------------------------------------------------------------------

    We are also specifically proposing to find that Wyoming's revised 
cost calculation is appropriate, including: (1) The use of actual 
annual average (2013-2015) NO<INF>X</INF> emissions rates for LNB/SOFA; 
(2) the use of NO<INF>X</INF> emissions rates of 0.15 and 0.05 lb/MMBtu 
(annual) for LNB/SOFA + SNCR and LNB/SOFA + SCR, respectively; (3) the 
use of amortization periods of 20, 20, and 30 years for LNB/SOFA, SNCR 
and SCR, respectively; (4) the use of actual costs for the installation 
and operation of SCR taken from those incurred for Units 3 and 4; and 
(5) the use of a baseline of 2001-2003 emissions to analyze cost and 
visibility associated with LNB/SOFA, LNB/SOFA + SNCR, and LNB/SOFA + 
SCR.
    However, as explained previously, notwithstanding our proposed 
finding that Wyoming reasonably characterized relevant information 
under each of the four statutory factors, we are proposing to find that 
the State did not reasonably consider that information in reaching its 
revised reasonable progress determination.
    Of the four reasonable progress factors and the optional visibility 
improvement factor, the State placed significant emphasis on the costs 
of compliance in its analysis of controls for Jim Bridger Units 1 and 
2. Consistent with the State's analysis, we afford this factor similar 
significance in our evaluation here. We are also evaluating the 
visibility improvement information that Wyoming considered in the SIP 
revision, as well as the other three factors--remaining useful life, 
time necessary for compliance, and energy and non-air environmental 
impacts. After a consideration of all five of these factors, we propose 
to conclude that the State's determination that the installation of SCR 
is not necessary for reasonable progress is unreasonable.
a. Costs of Compliance
    In order to evaluate Wyoming's 2020 SIP revision with respect to 
the cost of compliance, we first evaluate Wyoming's characterization of 
the costs using the updated Control Cost Manual. Next, we evaluate the 
reasonableness of the costs associated with the installation of SCR on 
Units 1 and 2 with respect to average and incremental cost-
effectiveness and the State's explanation for why requiring SCR on 
Units 1 and 2 is unreasonable.
    The revised NO<INF>X</INF> control cost estimates in Wyoming's 2020 
SIP revision are based on the current version of the Control Cost 
Manual, which has been revised since our 2014 final rule. As updated, 
the Control Cost Manual includes a 30-year equipment life for SCR.\80\ 
The change in equipment life estimate from 20 to 30 years for SCR 
affects annual cost estimates, as well as average cost-effectiveness 
and incremental cost-effectiveness estimates. We propose to find 
Wyoming's use of the updated Control Cost Manual appropriate.
---------------------------------------------------------------------------

    \80\ EPA, ``Control Cost 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 December 2021).
---------------------------------------------------------------------------

    In the 2020 SIP revision, Wyoming provided updated capital costs, 
annual costs, and average and incremental cost-effectiveness figures 
for SNCR, SCR, and the plant-wide annual and monthly limits.\81\ The 
2007 Guidance instructs that states should evaluate both average and 
incremental costs according to the Control Cost Manual to maintain and 
improve consistency.\82\ These figures take into account capital and 
annual costs and allow states and EPA to compare costs of controls 
industry wide. EPA's guidance further cautions against

[[Page 2582]]

considering in isolation the capital costs of a control option, as 
large or small capital costs alone are not dispositive of the 
reasonableness of a potential control.\83\ Thus, we deem the average 
and incremental cost-effectiveness figures most relevant to our 
consideration of Wyoming's revised cost analysis.
---------------------------------------------------------------------------

    \81\ Wyoming 2020 SIP Revision at 4-5.
    \82\ 2007 Guidance at page 5-1, 2 (referring to the BART 
Guidelines and Control Cost Manual). See also 40 CFR part 51, 
appendix Y, IV.D.4.b (``For purposes of air pollutant analysis, 
`effectiveness' is measured in terms of tons of pollutant emissions 
removed, and `cost' is measured in terms of annualized control 
costs. We recommend two types of cost-effectiveness calculations--
average cost effectiveness, and incremental cost effectiveness.'').
    \83\ See 40 CFR part 51, appendix Y, IV.D.4.g.
---------------------------------------------------------------------------

    In the revised cost analysis for the 2020 SIP revision, Wyoming's 
cost estimates show an average cost-effectiveness for LNB/SOFA + SCR 
for Units 1 and 2 of $1,997 and $2,228 per ton of NO<INF>X</INF> 
removed, respectively.\84\ Wyoming's cost estimates also show an 
incremental cost-effectiveness for LNB/SOFA + SCR for Units 1 and 2 of 
$4,410 and $4,510 per ton of NO<INF>X</INF> removed, respectively, 
relative to the next-most-stringent control (LNB/SOFA + SNCR).\85\
---------------------------------------------------------------------------

    \84\ See Table 4 in this document. Because we are finding the 
most stringent control technology (SCR) reasonable, and because 
Wyoming did not request that we evaluate other control technologies, 
we are not evaluating additional control technologies. See 40 CFR 
part 51, appendix Y, IV.D.1.9.
    \85\ See Table 4 in this document.
---------------------------------------------------------------------------

    Based on the State's estimates, the costs of the existing control 
requirements (LNB/SOFA + SCR) are eminently reasonable. Indeed, in 
2011, the State deemed reasonable an average cost-effectiveness of 
$2,258 per ton of NO<INF>X</INF> removed (LNB/SOFA + SCR) and 
incremental cost-effectiveness of $5,721 per ton of NO<INF>X</INF> 
removed (LNB/SOFA + SCR) for each unit when it required SCRs as 
reasonable progress controls.\86\ Similarly, EPA concluded in our 2014 
final rule that our revised average cost-effectiveness figures for LNB/
SOFA + SCR for Units 1 and 2 of $2,635 and $3,403 per ton and our 
revised incremental cost-effectiveness figures for LNB/SOFA + SCR for 
Units 1 and 2 of $7,447 and $8,968 were reasonable.\87\
---------------------------------------------------------------------------

    \86\ 77 FR 33053.
    \87\ 79 FR 5048.
---------------------------------------------------------------------------

    Relatedly, in our 2014 final rule, we required through a Federal 
implementation plan an emission limit consistent with the installation 
of new LNB/OFA + SCR at four other units in Wyoming with higher cost-
effectiveness figures: LNB/OFA + SCR at Laramie River Station Units 1, 
2, and 3 had an average cost-effectiveness of $4,461, $4,424, and 
$4,375 per ton and incremental cost-effectiveness of $5,449, $5,871, 
and $5,667 per ton, respectively,\88\ and LNB/OFA + SCR at Wyodak had 
an average cost-effectiveness of $4,036 per ton and incremental cost-
effectiveness of $6,233 per ton.\89\
---------------------------------------------------------------------------

    \88\ 79 FR 5039-40. The NO<INF>X</INF> emission limit for Units 
1, 2, and 3 were revised (through settlement) on May 20, 2019, to 
0.06 lb/MMBtu by July 1, 2019, 0.15 lb/MMBtu by December 31, 2018, 
and 0.15 lb/MMBtu by December 31, 2018, respectively. 84 FR 22711 
(May 20, 2019).
    \89\ 79 FR 5044. The NO<INF>X</INF> emission limit at Wyodak is 
subject to ongoing litigation and settlement discussions.
---------------------------------------------------------------------------

    Thus, the revised average cost-effectiveness and incremental cost-
effectiveness for installing SCR on Jim Bridger Units 1 and 2 in 
Wyoming's 2020 SIP revision are even lower than what Wyoming determined 
were reasonable for the same units in 2011. And the revised cost-
effectiveness figures are even lower than what EPA in 2014 determined 
were reasonable for Jim Bridger Units 1 and 2 and for four other units 
addressed in the 2014 final rule.\90\
---------------------------------------------------------------------------

    \90\ The examples cited by Wyoming in the 2020 SIP revision do 
not establish that the revised cost-effectiveness figures for Jim 
Bridger Units 1 and 2 are unreasonable. Indeed, the average cost-
effectiveness figures in the examples are higher than or similar to 
Wyoming's revised cost estimates. See 80 FR 18944, 18975 (April 8, 
2015) (proposed rule stating that LNB/SOFA + SCR average ($3,552 and 
$2,749 per ton) and incremental ($6,717 and $5,736 per ton) cost-
effectiveness figures were ``within the range of what we consider to 
be cost-effective'' for BART but incremental visibility improvement 
of 0.069 deciviews at a single Class I area is ``relatively small'' 
in light of incremental cost-effectiveness figures); 77 FR 21896, 
21901 (April 12, 2012) (proposed rule stating that LNB/OFA + SCR 
average cost-effectiveness figures of $2,110, $1,967, and $2,183 and 
incremental cost-effectiveness figures of $4,534, $4,330, and $2,756 
were not cost prohibitive or sufficiently large to warrant 
eliminating SCR from consideration as BART).
---------------------------------------------------------------------------

    In 2014, EPA ultimately deferred to Wyoming's BART and reasonable 
progress determinations for Jim Bridger, even though the available 
information suggested that SCR was reasonable as BART, given the 
State's commitment to require SCR as reasonable progress controls. But 
here, the State submitted a SIP revision that does not warrant such 
deference. Specifically, the cost associated with installing and 
operating the currently required controls on Jim Bridger Units 1 and 2 
has not increased beyond what the State determined in 2011 was 
reasonable. Wyoming has asserted only that not requiring emission 
limits reflecting SCR for Units 1 and 2 will be less costly than 
requiring them and the amount that PacifiCorp has spent to date on 
NO<INF>X</INF> control technology at Jim Bridger is sufficient for 
reasonable progress. Neither of these justifications offers a 
compelling basis for removing the existing control requirements, as 
both were expected and acknowledged at the time of Wyoming's 2011 
decision to require the controls. Additionally, we note again that the 
expected fleetwide installations of SCRs that PacifiCorp had previously 
anticipated have not come to pass.\91\ Regardless, in 2011, Wyoming 
determined the costs the source would incur were reasonable and that 
emission limits reflecting LNB/SOFA + SCR are necessary to meet the 
statutory requirements. The State has offered no reasonable explanation 
for its reversal, i.e., for why the revised, even lower cost-
effectiveness estimates for SCR are now unreasonable such that an 
emission limit associated with SCR is no longer necessary to meet the 
requirement to make reasonable progress.
---------------------------------------------------------------------------

    \91\ See supra note 37.
---------------------------------------------------------------------------

    In summary, we disagree with Wyoming that the cost analysis 
strongly favors removing the existing SCR-based requirement \92\ for 
the following reasons: (1) The average cost-effectiveness and 
incremental cost-effectiveness for installing SCR on Units 1 and 2 in 
Wyoming's 2020 SIP revision are even lower than what Wyoming determined 
were reasonable in 2011 and lower than what we found to be reasonable 
for the installation of LNB/SOFA + SCR in similar instances in 2014; 
(2) the State has offered no reasonable explanation for why the 
revised, lower cost-effectiveness estimates for SCR are now 
unreasonable; and (3) Wyoming has not provided any new information that 
would support a revised determination that the costs of the existing 
control requirements are now unreasonable.
---------------------------------------------------------------------------

    \92\ Wyoming 2020 SIP Revision at 5.
---------------------------------------------------------------------------

b. Visibility Improvement
    For Jim Bridger, the projected visibility improvements associated 
with the installation of LNB/SOFA and SCR are between 0.27-0.37 and 
0.27-0.36 deciviews for Units 1 and 2, respectively, at the most 
impacted Class I area, Bridger Wilderness (Table 6). Additionally, the 
installation of SCR at Units 1 and 2 would result in visibility 
improvement at numerous other Class I areas.\93\
---------------------------------------------------------------------------

    \93\ For Jim Bridger Unit 1, using monthly varying ammonia 
concentrations, model visibility improvements with LNB/OFA + SCR 
were 0.37 deciviews at Bridger; 0.26 deciviews at Fitzpatrick; 0.29 
deciviews at Mt Zirkel; 0.35 deciviews at Rawah; 0.36 deciviews at 
Rocky Mountain; 0.17 deciviews at Grand Teton; 0.14 deciviews at 
Teton; 0.19 deciviews at Washakie; and 0.15 deciviews at 
Yellowstone. For Jim Bridger Unit 1, using a constant 0.5 ppb 
ammonia concentration, model visibility improvements with LNB/OFA/
SCR were: 0.37 deciviews at Bridger; 0.26 deciviews at Fitzpatrick; 
0.29 deciviews at Mt Zirkel; 0.35 deciviews at Rawah; 0.36 deciviews 
at Rocky Mountain; 0.17 deciviews at Grand Teton; 0.14 deciviews at 
Teton; 0.19 deciviews at Washakie; and 0.15 deciviews at 
Yellowstone. For Jim Bridger Unit 2, using monthly varying ammonia 
concentrations, model visibility improvements with LNB/OFA/SCR were: 
0.36 deciviews at Bridger; 0.26 deciviews at Fitzpatrick; 0.28 
deciviews at Mt Zirkel; 0.35 deciviews at Rawah; 0.36 deciviews at 
Rocky Mountain; 0.16 deciviews at Grand Teton; 0.14 deciviews at 
Teton; 0.19 deciviews at Washakie; and 0.14 deciviews at 
Yellowstone. For Jim Bridger Unit 2, using a constant 0.5 ppb 
ammonia concentration, model visibility improvements with LNB/OFA/
SCR were: 0.36 deciviews at Bridger; 0.26 deciviews at Fitzpatrick; 
0.28 deciviews at Mt Zirkel; 0.35 deciviews at Rawah; 0.36 deciviews 
at Rocky Mountain; 0.16 deciviews at Grand Teton; 0.14 deciviews at 
Teton; 0.19 deciviews at Washakie; and 0.14 deciviews at 
Yellowstone. 79 FR 5041.

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

[[Page 2583]]

    As an initial matter, Wyoming mischaracterizes our 2014 final rule 
in its 2020 SIP revision when it asserts that EPA ``determined that the 
unit-specific visibility benefits for LNB/SOFA + SCR installation on 
Units 1 and 2 were `modest' (0.27 to 0.37 deciviews).'' \94\ In the 
2014 final rule, EPA stated that the visibility improvement associated 
with the installation of SCR is ``significant on a source-wide basis 
(1.25 to 1.5 deciviews),'' while ``[t]he unit-specific benefits for 
Units 1 and 2 are somewhat more modest (0.27-0.37 deciviews).'' \95\ 
That is to say, the unit-specific benefits were relatively less than 
the benefits for the entire source, which will always be the case. 
Thus, we did not characterize the visibility improvement associated 
with the installation of SCR at Jim Bridger Units 1 and 2 as merely 
``modest,'' and we do not agree with Wyoming's characterization of the 
associated visibility improvement as such now. The fact remains that 
the installation of SCR at Jim Bridger Units 1 and 2 would yield 
appreciable visibility improvement at a reasonable cost.
---------------------------------------------------------------------------

    \94\ Wyoming 2020 SIP Revision at 7.
    \95\ 79 FR 5048 (emphasis added).
---------------------------------------------------------------------------

    States choosing to consider visibility benefits as an optional 
additional factor should not use visibility to summarily dismiss cost-
effective potential controls. This is because the CAA does not 
explicitly list visibility as a factor that must be considered in 
reasonable progress determinations.\96\ In this case, Wyoming is 
rejecting additional controls at Units 1 and 2, regardless of whether 
they are cost-effective, because ``installation of SCR on Units 1 & 2 
would result in only modest incremental visibility benefits of .10 to 
.15 deciviews (per unit) when compared to LNB/SOFA on Units 1 and 2.'' 
This is a generally inappropriate basis on which to make reasonable 
progress determinations for sources. Furthermore, because Units 1 and 2 
already have been controlled under BART, additional controls would be 
expected to make relatively smaller contributions to visibility 
improvement as a proportion of total impairment. This does not mean, 
however, that such sources need not be controlled in order to achieve 
the national visibility goal.\97\ To the contrary, the evaluation and 
control of BART sources such as Jim Bridger Units 1 and 2 under the 
reasonable progress requirements will be necessary to achieve the 
national goal of the prevention of any future, and the remedying of any 
existing manmade impairment of visibility in Class I areas.\98\
---------------------------------------------------------------------------

    \96\ Compare 42 U.S.C. 7491(g)(2) (including visibility as a 
factor in BART determinations) with id. 7491(g)(1) (visibility not 
included as an explicit factor in reasonable progress 
determinations); see also EPA, ``Clarifications Regarding Regional 
Haze State Implementation Plans for the Second Implementation 
Period,'' July 8, 2021 (``July 2021 Clarifications Memo'') at 12-13, 
available at https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf; 82 FR 3078, 3093 (January 
10, 2017) (because regional haze is caused by emissions from 
numerous sources, in order to address it, states may not abandon 
controls they already have determined are reasonable based on the 
four statutory factors on the basis that impact on visibility 
conditions is subjectively assessed as not ``meaningful'').
    \97\ See id.; see also 40 CFR 51.308(e)(5) (after a state has 
met BART requirements, BART-eligible sources are subject to 
reasonable progress requirements in the same manner as other 
sources).
    \98\ As with Wyoming's cost-effectiveness examples, Wyoming's 
visibility examples do not support Wyoming's conclusions regarding 
visibility improvement. Each is an example of a proposed BART 
determination that does not address the fact that, in many 
instances, reasonable progress controls naturally yield relatively 
smaller visibility improvement over already-installed BART controls. 
Thus, the fact that we proposed to reject controls of a certain 
cost-effectiveness and visibility improvement for BART does not 
necessitate rejecting similar controls for reasonable progress. See 
77 FR 24794, 24818 (April 25, 2012) (proposed rule stating that SCR 
is cost-effective for BART at $5,358 per ton but visibility 
improvement at the most impacted Class I area of 0.254 deciviews and 
cumulative visibility improvement at seven Class I areas of 0.273 
deciviews are small and thus EPA proposed to approve determination 
that BART is not SCR); 77 FR 11879, 11891 (February 28, 2012) 
(proposed rule stating that EPA proposed to agree with state 
determination that certain controls for a refinery were not BART due 
to high costs (unavailable) and small visibility gains (0.045 to 
0.16 deciview range)); 77 FR 18052, 18066 (March 26, 2012) (proposed 
rule stating that EPA proposed to agree with the state's 
determination that SCR was not BART given high cost-effectiveness 
($9,900 and $15,290 per ton) and low visibility improvement (under 
0.2 deciviews)); 77 FR 23988, 24013 (April 20, 2012) (proposed rule 
stating that SO<INF>2</INF> BART controls were cost-effective when 
values ranged from $1400 to $4800 per ton but visibility improvement 
ranges of 0.033 and 0.18 were ``relatively small'').
---------------------------------------------------------------------------

    Finally, in Wyoming's 2020 SIP revision, the visibility improvement 
remains unchanged from our 2014 final rule, and the State has provided 
no new visibility information to support a revised NO<INF>X</INF> 
reasonable progress determination that the existing control 
requirements are now unreasonable. In summary, we disagree with 
Wyoming's assertion that the visibility benefits are not sufficiently 
meaningful to warrant cost-effective controls.
c. Other Factors
    Relevant to energy and non-air quality environmental impacts, the 
State noted that SCR will produce solid waste when the catalyst is 
replaced periodically, and that requiring SCR will require 
significantly more electricity than LNB/SOFA. EPA's 2007 Guidance 
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.\99\ 
PacifiCorp did so in the revised cost analysis for the 2020 SIP 
revision. As explained elsewhere in this document, even with the energy 
and non-air environmental costs incorporated into the cost analysis, 
the cost-effectiveness of SCR remains reasonable.
---------------------------------------------------------------------------

    \99\ 2007 Guidance at 5-2 and 5-3.
---------------------------------------------------------------------------

    Additionally, the 2007 Guidance points to 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 argue against selection 
of that technology, especially if the control has been applied to 
similar facilities elsewhere and the waste is similar to those other 
applications.\100\ Wyoming has merely pointed out that the existing 
controls on Units 1 and 2 (LNB/SOFA) require less electricity to 
operate than SNCR or SCR and that SCR requires periodic catalyst 
replacement. The State has not demonstrated that the anticipated energy 
expenditure or waste that would be generated at Units 1 and 2 would be 
any different from the numerous other units for which states or EPA 
have required SCR. Indeed, Wyoming has already determined that energy 
and non-air environmental impacts did not disqualify SCR from being a 
reasonable control technology for two units at the same facility, i.e., 
at Jim Bridger Units 3 and 4.\101\ Based on EPA's long-standing 
guidance and the fact that the State has not provided any evidence to 
support a conclusion that the energy and non-air environmental impacts 
of SCR at Units 1 and 2 are unreasonable, we disagree that these 
factors support a conclusion that SCR is not the reasonable choice of 
control.
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    \100\ 2007 Guidance at 5-2 and 5-3; 40 CFR part 51, appendix Y, 
IV.D.4.h-i.
    \101\ Additionally, in its 2011 SIP submission Wyoming did not 
identify any energy or non-air quality environmental impacts that 
would preclude selection of any of the controls evaluated for Jim 
Bridger, including LNB/SOFA + SCR. See 78 FR 34753.

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[[Page 2584]]

    With respect to remaining useful life, as stated above, Wyoming did 
not provide an enforceable shutdown date that would ensure that the 
expected life of Jim Bridger Units 1 and 2 would be less than the 
expected life of the control technology. Thus, Wyoming appropriately 
used the Control Cost Manual remaining useful life for SCR of 30 years 
in the cost analysis.
    With respect to time necessary for compliance, Wyoming noted that 
the LNB/SOFA are already in use and thus, in contrast to SCR and SNCR, 
do not need any additional time for compliance. The deadline for Jim 
Bridger Units 1 and 2 to comply with the existing control requirements 
reflecting installation and operation of SCR by December 31, 2022 and 
December 31, 2021, respectively has existed in the SIP since 2014. We 
thus do not believe it is reasonable for the State to consider the time 
necessary for compliance as weighing in favor of not requiring SCRs as 
reasonable progress controls.
d. Summary of EPA's Evaluation of Wyoming's Reasonable Progress 
Demonstration
    In summary, we propose to disapprove Wyoming's reasonable progress 
demonstration concluding that the NO<INF>X</INF> emission limits 
associated with LNB/SOFA controls are the reasonable choice for Jim 
Bridger Units 1 and 2. We base our proposed disapproval on the 
following: (1) The reasonable average cost-effectiveness and 
incremental cost-effectiveness of the existing control requirements for 
Jim Bridger Units 1 and 2; (2) the appreciable visibility improvement 
estimated to result from compliance with the existing reasonable 
progress control requirements; (3) the fact that the State previously 
determined that the costs of those control requirements were reasonable 
given the visibility benefits, and thus necessary to satisfy the 
statutory requirements, and has not provided any new information that 
would support a revised determination that the existing control 
requirements are now unreasonable. Ultimately, we propose to find that 
because the State failed to justify its conclusion that the existing 
SCR requirements should be removed such that no further controls beyond 
BART are required for Jim Bridger Units 1 and 2, we cannot reasonably 
approve Wyoming's 2020 SIP revision. Because removing the existing SCR 
requirements would be inconsistent with the statutory requirement that 
SIPs contain the measures necessary to make reasonable progress, we are 
proposing to disapprove Wyoming's 2020 SIP revision.

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

    Wyoming's SIP revision includes ``an alternative regional haze 
compliance strategy for the Jim Bridger Power Plant'' \102\ that 
Wyoming considered as supplemental information to its revised four-
factor reasonable progress analysis and determination. Wyoming asserts 
that the alternative regional haze compliance strategy's plant-wide 
monthly and annual NO<INF>X</INF> and SO<INF>2</INF> emission limits 
are designed to reduce regional haze and create numerous other 
environmental benefits toward achieving natural visibility conditions 
at its Class I areas.\103\
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    \102\ Letter from Todd Parfitt, Director, Wyoming Department of 
Environmental Quality, to Gregory Sopkin, Regional Administrator, 
USEPA Region 8, Subject: State Implementation Plan Approval 
Request--Regional Haze 309(g) SIP Revision for PacifiCorp Jim 
Bridger Power Plant (May 12, 2020). See also Wyoming 2020 SIP 
Revision at 3.
    \103\ Wyoming 2020 SIP Revision at 9.
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    The 2020 SIP revision provides that the State ``considered it 
appropriate to re-balance and reconsider its [reasonable progress/long-
term strategy] determination and complete a four factor reasonable 
progress analysis on a NO<INF>X</INF>-only basis.'' \104\ Our proposed 
disapproval of Wyoming's reasonable progress determination for Jim 
Bridger Units 1 and 2 is thus based solely on the source-specific 
NO<INF>X</INF> reasonable progress analysis, as this analysis and 
resulting determination were intended to replace the State's previous 
NO<INF>X</INF>-only determination. However, we are also proposing to 
find that we cannot approve, and are therefore proposing to disapprove, 
the plant-wide emission limits, which rely on a comparative analysis 
that includes both NO<INF>X</INF> and SO<INF>2</INF> emissions 
reductions.
---------------------------------------------------------------------------

    \104\ Id. at 3.
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    EPA is proposing to disapprove the plant-wide monthly 
NO<INF>X</INF> and SO<INF>2</INF> emission limits because we cannot 
render a SIP more stringent than intended by the state through a 
partial SIP approval.\105\ While Wyoming has discretion to consider 
these limits,\106\ it is our understanding that Wyoming intended to 
adopt and make enforceable the plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits, as proposed by 
PacifiCorp, in lieu of the required emission limits associated with the 
installation of SCR on Units 1 and 2 and not in addition to the 
required emission limits associated with the installation of SCR.\107\ 
That is, we understand that Wyoming did not intend to implement the 
plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits together with SCR on Jim Bridger Units 1 and 2. 
Implementing a NO<INF>X</INF> emission limit consistent with the 
installation of SCR together with plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits would effectively 
increase the stringency of the SIP beyond what was intended in the 
Wyoming 2020 SIP revision.\108\ Thus, because EPA cannot render 
Wyoming's SIP more stringent than intended by the State through a 
partial SIP approval, and because we are proposing to disapprove 
Wyoming's revised NO<INF>X</INF> reasonable progress determination as 
unreasonable, we are also proposing to extend our disapproval to the 
State's plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits. Wyoming may choose to submit the plant-wide monthly 
and annual NO<INF>X</INF> and SO<INF>2</INF> emission limits to EPA in 
a stand-alone SIP submittal if the State would like to incorporate 
these emission limits into its SIP independent of the revised 
NO<INF>X</INF> reasonable progress analysis and determination for Jim 
Bridger Units 1 and 2 contained in the 2020 SIP revision. For example, 
some form of plant-wide mass limits could serve as a SIP strengthening 
measure.
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    \105\ Bethlehem Steel Corp. v. Gorsuch, 742 F.2d 1028, 1036 (7th 
Cir. 1984).
    \106\ As stated above, Wyoming has discretion to evaluate 
factors (beyond the four factors) that it considers relevant in 
formulating its long-term strategy, 2007 Guidance at page 5-1, so 
long as it does so reasonably and in a manner consistent with the 
statute and other applicable requirements. 42 U.S.C. 7491(b)(2)(B); 
40 CFR 51.308(d)(1)(iii).
    \107\ Wyoming 2020 SIP Revision at 9, 10, and 12.
    \108\ Implementation of NO<INF>X</INF> limits consistent with 
installing SCRs on Units 1 and 2, combined with the plant-wide 
monthly SO<INF>2</INF> limits would likely result in some 
SO<INF>2</INF> reductions (from the monthly plant-wide limits) plus 
additional NO<INF>X</INF> reductions (from meeting the 0.07 lb/MMBtu 
limits on Units 1 and 2) that are beyond what was intended in the 
SIP revision.
---------------------------------------------------------------------------

    In addition to the legal basis for proposing to disapprove the 
plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits, we also note two additional considerations. These 
considerations relate to Wyoming and PacifiCorp's quantitative analyses 
in support of the plant-wide limits, which assume that Jim Bridger is 
still operating at historical (2001-2003) levels. Although we are not 
relying on these considerations as the basis of our proposed 
disapproval, we provide them here for completeness.
    First, Wyoming analyzed the plant-wide limits assuming Jim 
Bridger's emissions are consistent with the plant's ``current operating 
potential.'' \109\ As explained above, PacifiCorp's analysis defines 
``current operating potential'' as

[[Page 2585]]

a combination of recent emission rates with plant-wide heat input 
(i.e., utilization) from the 2001-2003 period. Thus, the majority of 
the emissions reductions that Wyoming credited to the plant-wide limits 
\110\ would be realized only if Jim Bridger was utilized at levels 
consistent with the 2001-2003 period. However, recent utilization of 
the plant, based on the 2017-2020 period, has been much lower.\111\ EPA 
examined emissions and operations data from the 2017 to 2020 period 
because it reflects (1) full operation of the SCRs on Units 3 and 4 
that were installed in 2015 and 2016, respectively, (2) earlier 
SO<INF>2</INF> scrubber upgrades on all four units, and (3) recent 
trends in plant operations, as hours of operation and heat input. To 
the extent Wyoming's demonstration relies on historical (2001-2003) 
utilization to show that the plant-wide monthly and annual 
NO<INF>X</INF> and SO<INF>2</INF> emission limits achieve greater 
emissions reductions (and therefore greater visibility improvement) 
than SCRs on Units 1 and 2,\112\ neither the CAA nor the Regional Haze 
Rule provide a basis for such reliance.\113\
---------------------------------------------------------------------------

    \109\ Wyoming 2020 SIP Revision at 9.
    \110\ See Wyoming 2020 SIP Revision at 9 (plant-wide emission 
limits would result in combined NO<INF>X</INF> and SO<INF>2</INF> 
reduction of 6,056 tons/year).
    \111\ Compare PacifiCorp Reassessment, Attachment 1 at 21 
(providing 2001-2003 average heat input used as baseline for cost-
effectiveness analysis) with EPA Calculations for Wyoming 2020 SIP 
Revision (January 7, 2022) (Tab 1).
    \112\ See, e.g., Wyoming 2020 SIP Revision at 9 (PacifiCorp's 
comparative analysis of the existing control requirements and plant-
wide emission limits indicates the limits ``produce better modeled 
visibility and greater environmental benefits than installation of 
SCR or SNCR'').
    \113\ Unlike the BART program, which includes an extensive 
regulatory framework under which states can rely on such historical 
emissions and utilization data to demonstrate that a BART 
alternative achieves greater reasonable progress than BART, neither 
the CAA nor the Regional Haze Rule contain a similar framework for 
reasonable progress. Compare 40 CFR 51.308(e)(2) and (3) with 
(d)(1)(i)(A) and (d)(3).
---------------------------------------------------------------------------

    Second (and relatedly), based on recent (2017-2020) operation of 
the plant, we believe it is reasonable to conclude that the plant-wide 
monthly and annual NO<INF>X</INF> and SO<INF>2</INF> emission limits 
would not actually achieve similar or greater emissions reductions and 
visibility improvement compared to the installation of SCR on Units 1 
and 2 as Wyoming contends.
    Wyoming claims that the plant-wide limits will produce greater 
visibility improvement compared to the installation of two additional 
SCRs on Units 1 and 2. However, the CALPUFF visibility modeling inputs, 
and therefore visibility modeling results, are premised on assumptions 
about Jim Bridger's baseline utilization and emissions. Again, Wyoming 
analyzed the plant-wide emission limits assuming Jim Bridger's 
emissions were consistent with its plant-wide heat input from the 2001-
2003 period. That is, the modeling analysis assumes heat input from a 
historical period that does not correspond to how the facility is 
currently operated.\114\ The plant-wide 2017-2020 average utilization 
is approximately 29 percent below 2001-2003 average levels.\115\ Based 
on the assumption of plant-wide heat input from the 2001-2003 period, 
the analysis of the plant-wide limits by PacifiCorp and Wyoming 
estimates a reduction of 5,049 tpy of SO<INF>2</INF> and 1,007 tpy of 
NO<INF>X</INF>. Had the quantitative analysis been based on Jim 
Bridger's current utilization, it would have shown that the plant-wide 
limits would actually achieve far fewer emissions reductions going 
forward.\116\ For example, the proposed annual plant-wide 
SO<INF>2</INF> + NO<INF>X</INF> emission limit is 17,500 tpy. However, 
in the 2017-2020 period, plant-wide annual SO<INF>2</INF> + 
NO<INF>X</INF> emissions have ranged from 14,823 to 16,004 tpy.\117\ 
Therefore, Jim Bridger is already operating well below the proposed 
annual plant-wide SO<INF>2</INF> + NO<INF>X</INF> emission limits. 
Consequently, any annual SO<INF>2</INF> and NO<INF>X</INF> reductions 
based on the source's actual current operations would be much smaller 
than estimated from the analysis of a potential historical operation 
basis.
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    \114\ PacifiCorp Reassessment at 7. The PacifiCorp Reassessment 
also references annual heat input values that were not disclosed to 
EPA due to confidential forecasted capacity factors (see Attachment 
3B to Attachment 1). Therefore, some assumptions are unknown and 
impossible to replicate.
    \115\ Compare PacifiCorp Reassessment, Attachment 1 at 21 
(providing 2001-2003 average heat input used as baseline for cost-
effectiveness analysis) with EPA Calculations for Wyoming 2020 SIP 
Revision (January 7, 2022) (Tab 1).
    \116\ Wyoming and PacifiCorp used the 2001-2003 period as the 
baseline for the revised cost estimates in the Wyoming 2020 SIP 
Revision's NO<INF>X</INF>-only four-factor analysis for Jim Bridger 
Units 1 and 2. EPA believes this is a reasonable approach given the 
circumstances, particularly that the purpose was to compare the 
costs of different controls against a common baseline and that the 
cost and visibility figures relied on for that analysis were 
originally calculated for BART purposes. In contrast, EPA 
understands the purpose of the quantitative analysis accompanying 
the plant-wide monthly and annual NO<INF>X</INF> and SO<INF>2</INF> 
emission limits was to determine whether they will result in greater 
prospective emissions reductions and visibility improvement than 
SCR. See, e.g., Wyoming 2020 SIP Revision at 12 (``In addition, 
PacifiCorp's visibility enhancing proposal to limit overall 
operations at all four Jim Bridger Units adds support to Wyoming's 
reasonable progress revision, and ensures that visibility 
improvements greater than SCR installation will be achieved for the 
State of Wyoming.''). In this context, using a historical 
utilization baseline that does not reflect current or likely future 
plant operation obfuscates the assessment of future potential 
emissions reductions.
    \117\ EPA Calculations for Wyoming 2020 SIP Revision (January 7, 
2022) (Tab 1). Data based on the information obtained from EPA's 
Clean Air Markets Division (CAMD) database, available at: https://ampd.epa.gov/ampd/.
---------------------------------------------------------------------------

    Due to the complicated nature of the proposed monthly limits and a 
lack of complete information,\118\ EPA could not complete a full 
evaluation of the impact of the monthly limits on emissions and 
emissions reductions. However, based on the information available to 
EPA, it appears that while the proposed additional plant-wide monthly 
SO<INF>2</INF> and NO<INF>X</INF> limits may restrict SO<INF>2</INF> 
emissions (and to a lesser extent NO<INF>X</INF> emissions) in some 
months, the facility's recent operation has been emitting at levels 
similar to the proposed monthly limits.\119\ Thus, the plant-wide 
annual and monthly limits appear to result in few actual emissions 
reductions based on Jim Bridger's recent operation.
---------------------------------------------------------------------------

    \118\ See supra note 114.
    \119\ EPA Calculations for Wyoming 2020 SIP Revision (January 7, 
2022) (Tabs 3 and 4).
---------------------------------------------------------------------------

    In contrast, installation of two additional SCRs on Units 1 and 2 
will provide significant and certain additional NO<INF>X</INF> 
emissions reductions under any operating scenario compared to either 
recent operation or potential historical operation. With the current 
SIP emission limits of 0.07 lb/MMBtu (30-day rolling average) for Units 
1 and 2, additional SCRs on those two units would reduce annual 
NO<INF>X</INF> emissions by at least 3,000 tpy relative to the 2017-
2020 period (based on actual calendar month operation over that time 
period).\120\ Because the more recent data reflect the facility as it 
operates today (including emissions controls and limits that PacifiCorp 
and Wyoming assumed in the analysis of plant-wide limits), we believe 
it presents a reasonable set of operating conditions from which to 
evaluate which scenario would achieve greater combined NO<INF>X</INF> 
and SO<INF>2</INF> emissions reductions in future years. Furthermore, 
neither PacifiCorp nor Wyoming included any information that would 
indicate increased operation in the future.
---------------------------------------------------------------------------

    \120\ Id. at Tab 2.
---------------------------------------------------------------------------

    In conclusion, unlike the plant-wide NO<INF>X</INF> and 
SO<INF>2</INF> emission limits, installation of two additional SCRs 
provides significant NO<INF>X</INF> reductions of at least 3,000 tpy. 
Based on the information we have before us, we believe it is reasonable 
to conclude that the proposed plant-wide annual and monthly limits 
would not provide similar or greater emissions reductions or visibility 
improvement compared to the installation of two additional SCRs. This 
is especially true in comparison to recent operation of the Jim Bridger 
plant in the 2017 to 2020 period.

[[Page 2586]]

D. 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.'' \121\ Wyoming states that the 2020 SIP revision will 
not interfere with reasonable further progress or other applicable 
requirements because there are no areas in Wyoming that are currently 
designated nonattainment for NO<INF>X</INF> or particulate matter, and 
that with the reductions anticipated from the plant-wide annual and 
monthly limits, the SIP revision will not interfere with attainment or 
maintenance of the National Ambient Air Quality Standards (NAAQS).\122\
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    \121\ 43 U.S.C. 7410(l). 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 National Ambient Air Quality 
Standards (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 
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.
    \122\ Wyoming 2020 SIP Revision at 13. We note, however, that 
NO<INF>X</INF> is not a criteria pollutant itself but instead 
represents a group of highly reactive gases that includes the 
criteria pollutant nitrogen dioxide (NO<INF>2</INF>).
---------------------------------------------------------------------------

    As an initial matter, we note that Wyoming's evaluation pursuant to 
CAA section 110(l) is overly narrow and does not address all relevant 
NAAQS-related considerations. Additionally, CAA section 110(l) applies 
to all requirements of the CAA, not just the attainment and maintenance 
of the NAAQS. The previous sections of this document explain how the 
State failed to justify its conclusion that the existing SCR 
requirements should be removed such that no further controls beyond 
BART are necessary for Jim Bridger Units 1 and 2 for reasonable 
progress in the first planning period. Based on our proposed 
conclusions in section IV.B in this document, we propose to find that 
removing the SCR requirement would interfere with the regional haze 
requirements of the CAA, specifically, with the requirement that SIPs 
contain the emission limits, schedules of compliance, and other 
measures that are necessary to make reasonable progress toward the 
national visibility goal. Accordingly, we propose to disapprove the 
Wyoming 2020 SIP revision under CAA section 110(l) in addition to the 
basis stated in section IV.B above.

E. Consultation With Federal Land Managers

    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 
proposed SIP revision no less than sixty days prior to the associated 
public hearing or public comment opportunity. On March 29, 2019, 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 provided the FLMs with sixty days to provide comments 
as well as the opportunity to discuss the draft SIP during a phone call 
on May 21, 2019.\123\ The State did not receive any comments from the 
FLMs. Therefore, we propose to find that Wyoming met its obligations 
for consultation in development of the Wyoming 2020 SIP revision.
---------------------------------------------------------------------------

    \123\ Amber Potts, Wyoming Department of Environmental Quality, 
Record of State of Wyoming, PacifiCorp, and Federal Land Manager 
Consultation Meeting for the Proposed Updates to the Regional Haze 
(Round 1) SIP Concerning the Jim Bridger Facility, May 21, 2019. See 
also Wyoming Department of Environmental Quality, FLM Consultation 
Meeting Slides.
---------------------------------------------------------------------------

V. Summary of EPA's Proposed Action

    In this action, EPA is proposing to disapprove the Wyoming 2020 SIP 
revision (as submitted in May 2020 and supplemented in September and 
October 2020), which includes amendments to Chapters 7.3.6 and 8 of 
Wyoming's regional haze SIP narrative, Addressing Regional Haze 
Visibility Protection For The Mandatory Federal Class I Areas Required 
Under 40 CFR 51.309, that contain a source-specific NO<INF>X</INF> 
reasonable progress analysis and revised determination for Jim Bridger 
Units 1 and 2. EPA is also proposing to disapprove the plant-wide 
monthly and annual NO<INF>X</INF> and SO<INF>2</INF> emission limits 
for Jim Bridger Units 1-4. Because we are proposing to disapprove the 
State's proposed revisions to its existing SIP requirements, we are not 
proposing to change any regulatory text, including text in 40 CFR 
52.2620 or 40 CFR 52.2636.

VI. 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, EPA's role is to approve state choices, 
provided that they meet the requirements of the CAA. As explained 
above, Wyoming's SIP submission does not meet the requirements of the 
CAA. Accordingly, this action merely proposes to disapprove state law 
as not meeting Federal requirements and does not impose additional 
requirements beyond those imposed by state law. For that reason, this 
action:
    <bullet> Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
    <bullet> Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
    <bullet> Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
    <bullet> Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
    <bullet> Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
    <bullet> Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
    <bullet> Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
    <bullet> Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
    <bullet> Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction. In those areas of Indian 
country, the proposed rule does not have tribal implications and will 
not impose substantial direct costs on tribal governments or preempt 
tribal law as specified by Executive Order 13175 (65 FR 67249, November 
9, 2000).

[[Page 2587]]

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: January 11, 2022.
KC Becker,
Regional Administrator, Region 8.
[FR Doc. 2022-00777 Filed 1-14-22; 8:45 am]
BILLING CODE 6560-50-P


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