[Federal Register Volume 83, Number 197 (Thursday, October 11, 2018)]
[Proposed Rules]
[Pages 51403-51418]
[FR Doc No: 2018-21949]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2018-0606; FRL-9984-85-Region 8]

Approval and Promulgation of Air Quality Implementation Plans;
Wyoming; Revisions to Regional Haze State Implementation Plan;
Revisions to Regional Haze Federal Implementation Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a State Implementation Plan (SIP) revision submitted by the
State of Wyoming on April 5, 2018, addressing regional haze. The
revisions modify the sulfur dioxide (SO2) emissions
reporting requirements for Laramie River Station Units 1 and 2. We are
also proposing to revise the nitrogen oxides (NOX) best
available retrofit technology (BART) emission limits for Laramie River
Units 1-3 in the Federal Implementation Plan (FIP) for regional haze in
Wyoming. The proposed revisions to the Wyoming regional haze FIP would
also establish a SO2 emission limit averaged annually across
both Laramie River Station Units 1 and 2. The EPA is proposing this
action pursuant to section 110 of the Clean Air Act (CAA).

DATES:
    Comments: Written comments must be received on or before November
13, 2018.
    Public Hearing: If anyone contacts us requesting a public hearing
on or before October 26, 2018, we will hold a hearing. Additional
information about the hearing, if requested, will be published in a
subsequent Federal Register document. Contact Jaslyn Dobrahner at (303)
312-6252, or at [email protected], to request a hearing or to
determine if a hearing will be held.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2018-0606, 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. The EPA may publish any comment received to its
public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit http://www.epa.gov/dockets/commenting-epa-dockets.
    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 either electronically
in www.regulations.gov or in hard copy at the Air Program,
Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop Street,
Denver, Colorado 80202-1129. The EPA requests that, if at all possible,
you contact the individual listed in the FOR FURTHER INFORMATION
CONTACT section to view the hard copy of the docket. You may view the
hard copy of the docket Monday through Friday, 8:00 a.m. to 4:00 p.m.,
excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Jaslyn Dobrahner, Air Program, EPA,
Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-
1129,<PHONE_NUMBER>, [email protected].

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

I. What action is the EPA proposing?
II. Background
    A. Requirements of the Clean Air Act and the EPA's Regional Haze
Rule

    B. Best Available Retrofit Technology (BART)
    C. BART Alternatives
    D. Reasonable Progress Requirements
    E. Consultation With Federal Land Managers (FLMs)
    F. Requirements for Regional Haze SIPs Submitted Under 40 CFR
51.309
    G. Regulatory and Legal History of the 2014 Wyoming SIP and FIP
III. Proposed FIP Revisions
    A. Background
    B. The BART Alternative
    C. The NOX Emission Limit for Laramie River Unit 1
IV. Proposed Action on Submitted SIP Revisions
    A. Background
    B. April 5, 2018 Submittal
    C. The EPA's Evaluation of the SO2 Emissions
Reporting Amendments
V. Clean Air Act Section 110(l)
VI. Consultation With FLMs
VII. The EPA's Proposed Action
VIII. Incorporation by Reference
IX. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

    On January 30, 2014, the EPA promulgated a final rule titled
``Approval, Disapproval and Promulgation of Implementation Plans; State
of Wyoming; Regional Haze State Implementation Plan; Federal
Implementation Plan for Regional Haze'' approving, in part, a regional
haze SIP revision submitted by the State of Wyoming on January 12,
2011.\1\ In the final rule, the EPA also disapproved, in part, the
Wyoming regional haze SIP, including the NOX BART emission
limit of 0.21 lb/MMBtu (30-day rolling average) for Laramie River Units
1-3, and promulgated a FIP that imposed a NOX BART emission
limit of 0.07 lb/MMBtu (30-day rolling average) for each of the three
Laramie River Units, among other actions.
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    \1\ 79 FR 5032 (January 30, 2014).
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    The EPA is proposing to revise the FIP per the terms of the
settlement agreement and amendment described in Section II.G. to amend
the NOX and SO2 emission limits for Laramie
River. Specifically, the EPA is proposing to: (1) Revise the
NOX emission limit and associated compliance date for Unit
1; (2) through the incorporation of a BART alternative, revise the
NOX emission limits for Units 2 and 3, and the
SO2 emission limit averaged annually across Units 1 and 2
along with the associated compliance dates; and (3) require selective
catalytic reduction (SCR) on Unit 1 and selective non-catalytic
reduction (SNCR) on Units 2 and 3. Although we are proposing to revise
the Wyoming regional haze FIP, Wyoming may always submit a new regional
haze SIP to the EPA for review and we would welcome such a submission.
The CAA requires the EPA to act within 12 months on a SIP submittal
that it determines to be complete. If Wyoming were to submit a SIP
revision meeting the requirements of the CAA and the regional haze
regulations, we would propose approval of the State's plan as
expeditiously as practicable.
    The EPA is also proposing to approve SIP revisions submitted by the
State of Wyoming on April 5, 2018, to amend the SO2
emissions reporting requirements for Laramie River Units 1 and 2.
Specifically, the EPA is proposing to approve the SO2
emissions reporting requirements for Laramie River Units 1 and 2, which
address how Basin Electric is required to calculate reportable
SO2 emissions, when Basin Electric is required to use the
revised SO2 emissions calculation method, and how the
reported SO2 emissions will be used within the context of
the SO2 emissions milestone inventory.

II. Background

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

    In section 169A of the 1977 Amendments to the CAA, Congress created
a program for protecting visibility in the nation's national parks and
wilderness areas. This section of the CAA establishes ``as a national
goal the prevention of any future, and the remedying of any existing,
impairment of visibility in mandatory Class I Federal areas which
impairment results from manmade air pollution.'' \2\
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    \2\ 42 U.S.C. 7491(a). Areas designated as mandatory Class I
Federal areas consist of national parks exceeding 6000 acres,
wilderness areas and national memorial parks exceeding 5000 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 section, we mean a
``mandatory Class I Federal area.''
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    The EPA promulgated a rule to address regional haze on July 1,
1999.\3\ The Regional Haze Rule (RHR) revised the existing visibility
regulations \4\ to integrate provisions addressing regional haze and
established a comprehensive visibility protection program for Class I
areas. The requirements for regional haze, found at 40 CFR 51.308 and
40 CFR 51.309, are included in the EPA's visibility protection
regulations at 40 CFR 51.300 through 40 CFR 51.309. The EPA revised the
RHR on January 10, 2017.\5\
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    \3\ 64 FR 35714, 35714 (July 1, 1999) (codified at 40 CFR part
51, subpart P).
    \4\ The EPA had previously promulgated regulations to address
visibility impairment in Class I areas that is ``reasonably
attributable'' to a single source or small group of sources, i.e.,
reasonably attributable visibility impairment (RAVI). 45 FR 80084,
80084 (December 2, 1980).
    \5\ 82 FR 3078 (January 10, 2017).
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    The CAA requires each state to develop a SIP to meet various air
quality requirements, including protection of visibility.\6\ Regional
haze SIPs must assure reasonable progress toward the national goal of
achieving natural visibility conditions in Class I areas. A state must
submit its SIP and SIP revisions to the EPA for approval. Once
approved, a SIP is enforceable by the EPA and citizens under the CAA;
that is, the SIP is federally enforceable. If a state elects not to
make a required SIP submittal, fails to make a required SIP submittal
or if we find that a state's required submittal is incomplete or not
approvable, then we must promulgate a FIP to fill this regulatory
gap.\7\
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    \6\ 42 U.S.C. 7410(a), 7491, and 7492(a); CAA sections 110(a),
169A, and 169B.
    \7\ 42 U.S.C. 7410(c)(1).
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B. Best Available Retrofit Technology (BART)

    Section 169A of the CAA directs states as part of their SIPs, or
the EPA when developing a FIP in the absence of an approved regional
haze SIP, to evaluate the use of retrofit controls at certain larger,
often uncontrolled, older stationary sources in order to address
visibility impacts from these sources. Specifically, section
169A(b)(2)(A) of the CAA requires states' implementation plans to
contain such measures as may be necessary to make reasonable progress
toward the natural visibility goal, including a requirement that
certain categories of existing major stationary sources built between
1962 and 1977 procure, install, and operate the ``Best Available
Retrofit Technology'' as determined by the states through their SIPs,
or as determined by the EPA when it promulgated a FIP. Under the RHR,
states (or the EPA) are directed to conduct BART determinations for
such ``BART-eligible'' sources that may reasonably be anticipated to
cause or contribute to any visibility impairment in a Class I area.\8\

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 provides greater
reasonable progress towards improving visibility than BART.\9\
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    \8\ 40 CFR 51.308(e). The EPA designed the Guidelines for BART
Determinations Under the Regional Haze Rule (Guidelines) 40 CFR
appendix Y to part 51 ``to help States and others (1) identify those
sources that must comply with the BART requirement, and (2)
determine the level of control technology that represents BART for
each source.'' Guidelines, Section I.A. Section II of the Guidelines
describes the four steps to identify BART sources, and Section III
explains how to identify BART sources (i.e., sources that are
``subject to BART'').
    \9\ 40 CFR 51.308(e)(2). WildEarth Guardians v. EPA, 770 F.3d
919 (10th Cir. 2014).
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C. BART Alternatives

    An alternative program to BART must meet requirements under 40 CFR
51.308(e)(2) and (e)(3). These requirements for alternative programs
relate to the ``better-than-BART'' test and fundamental elements of any
alternative program.
    In order to demonstrate that the alternative program achieves
greater reasonable progress than source-specific BART, a state, or the
EPA if developing a FIP, must demonstrate that its SIP meets the
requirements in 40 CFR 51.308(e)(2)(i) through (v). The state or the
EPA must conduct an analysis of the best system of continuous emission
control technology available and the associated reductions for each
source subject to BART covered by the alternative program, termed a
``BART benchmark.'' Where the alternative program has been designed to
meet requirements other than BART, simplifying assumptions may be used
to establish a BART benchmark.
    Pursuant to 40 CFR 51.308(e)(2)(i)(E), the state or the EPA, must
also provide a determination that the alternative program achieves
greater reasonable progress than BART under 40 CFR 51.308(e)(3) or
otherwise based on the clear weight of evidence. 40 CFR 51.308(e)(3),
in turn, provides specific tests applicable under specific
circumstances for determining whether the alternative achieves greater
reasonable progress than BART. If the distribution of emissions for the
alternative program is not substantially different than for BART, and
the alternative program results in greater emissions reductions, then
the alternative program may be deemed to achieve greater reasonable
progress. If the distribution of emissions is significantly different,
the differences in visibility between BART and the alternative program,
must be determined by conducting dispersion modeling for each impacted
Class I area for the best and worst 20 percent of days. This modeling
demonstrates ``greater reasonable progress'' if both of the two
following criteria are met: (1) Visibility does not decline in any
Class I area; and (2) there is overall improvement in visibility when
comparing the average differences between BART and the alternative
program across all the affected Class I areas. Alternatively, pursuant
to 40 CFR 51.308(e)(2), states may show that the alternative achieves
greater reasonable progress than the BART benchmark ``based on the
clear weight of evidence'' determinations. Specific RHR requirements
for alternative programs are discussed in more detail in Section
III.\10\
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    \10\ 40 CFR 51.308(e)(2).
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    Generally, a SIP or FIP addressing regional haze must include
emission limits and compliance schedules for each source subject to
BART. In addition to the RHR's requirements, general SIP requirements
mandate that the SIP or FIP include all regulatory requirements related
to monitoring, recordkeeping, and reporting for the alternative's
enforceable requirements. See CAA section 110(a); 40 CFR part 51,
subpart K.

D. Reasonable Progress Requirements

    In addition to BART requirements, as mentioned previously, each
regional haze SIP or FIP must contain measures as necessary to make
reasonable progress towards the national visibility goal. Finally, the
SIP or FIP must establish reasonable progress goals (RPGs) for each
Class I area within the state for the plan implementation period (or
``planning period''), based on the measures included in the long-term
strategy.\11\ If an RPG provides for a slower rate of improvement in
visibility than the rate under which the national goal of no
anthropogenic visibility impact would be attained by 2064, the SIP or
FIP must demonstrate, based on the four reasonable progress factors,
why that faster rate is not reasonable and the slower rate provided for
by the SIP or FIP's state-specific RPG is reasonable.\12\
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    \11\ 40 CFR 51.308(d).
    \12\ 40 CFR 51.308(d)(1)(ii).
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E. Consultation With Federal Land Managers (FLMs)

    The RHR requires that a state, or the EPA if promulgating a FIP
that fills a gap in the SIP with respect to this requirement, consult
with FLMs before adopting and submitting a required SIP or SIP
revision, or a required FIP or FIP revision.\13\ Further, the EPA, or
state when considering a SIP revision, must include in its proposal a
description of how it addressed any comments provided by the FLMs.
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    \13\ 40 CFR 51.308(i).
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F. Requirements for Regional Haze SIPs Submitted Under 40 CFR 51.309

    The EPA's RHR provides two paths to address regional haze. One is
40 CFR 51.308, requiring states to perform individual point source BART
determinations and evaluate the need for other control strategies. The
other method for addressing regional haze is through 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. By meeting the requirements under 40
CFR 51.309, a Transport Region State can be deemed to be making
reasonable progress toward the national goal of achieving natural
visibility conditions for 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: 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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    Section 309 requires those Transport Region States that choose to
participate to adopt regional haze strategies that are based on
recommendations from the Grand Canyon Visibility Transport Commission
(GCVTC) for protecting the 16 Class I areas on the Colorado Plateau.
The purpose of the GCVTC was to assess information about the adverse
impacts on visibility in and around the 16 Class I areas on the
Colorado Plateau and to provide policy recommendations to the EPA to
address such impacts. The GCVTC determined that all Transport Region
States could potentially impact the Class I areas on the Colorado
Plateau. The GCVTC submitted a report to the EPA in 1996 for protecting
visibility for the Class I areas on the Colorado Plateau, and the EPA
codified these recommendations as an option available to states as part
of the RHR.\15\
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    \15\ 64 FR 35714, 35749 (July 1, 1999).
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    The EPA determined that the GCVTC strategies would provide for
reasonable progress in mitigating regional haze if supplemented by an
annex containing quantitative emission reduction milestones and
provisions for a trading program or other alternative measure.\16\ In
September 2000, the Western

Regional Air Partnership (WRAP), which is the successor organization to
the GCVTC, submitted an annex to EPA. The annex contained
SO2 emissions reduction milestones and detailed provisions
of a backstop trading program to be implemented automatically if
voluntary measures failed to achieve the SO2 milestones. The
EPA codified the annex on June 5, 2003 at 40 CFR 51.309(h).\17\
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    \16\ 64 FR 35714, 35749, 35756 (July 1, 1999).
    \17\ 68 FR 33764, 33767 (June 5, 2003).
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    Five western states, including Wyoming, submitted implementation
plans under section 309 in 2003.\18\ The EPA was challenged by the
Center for Energy and Economic Development (CEED) on the validity of
the annex provisions. In CEED v. EPA, the D.C. Circuit Court of Appeals
vacated the EPA approval of the WRAP annex.\19\ In response to the
court's decision, the EPA vacated the annex requirements adopted under
40 CFR 51.309(h), but left in place the stationary source requirements
in 40 CFR 51.309(d)(4).\20\ The requirements under 40 CFR 51.309(d)(4)
contain general requirements pertaining to stationary sources and
market trading, and allow states to adopt alternatives to the point
source application of BART.
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    \18\ Five states--Arizona, New Mexico, Oregon, Utah and
Wyoming--and Albuquerque-Bernalillo County, New Mexico, initially
exercised this option by submitting plans to the EPA in December
2003. Oregon elected to cease participation in 2006, and Arizona
elected to cease participation in 2010.
    \19\ Ctr. for Energy & Econ. Dev. v. EPA, 398 F.3d 653, 654
(D.C. Cir. 2005).
    \20\ 71 FR 60612 (October 13, 2006).
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    Thus, rather than requiring source-specific BART controls as
explained previously in Section II.B., states have the flexibility to
adopt an emissions trading program or other alternative program if the
alternative provides greater reasonable progress than would be achieved
by the application of BART pursuant to 40 CFR 51.308(e)(2). Under 40
CFR 51.309, states can satisfy the SO2 BART requirements by
adopting SO2 emissions milestones and a backstop trading
program. Under this approach, states must establish declining
SO2 emissions milestones for each year of the program
through 2018. The milestones must be consistent with the GCVTC's goal
of 50 to 70 percent reduction in SO2 emissions by 2040. The
backstop trading program would be implemented if a milestone is
exceeded and the program is triggered.\21\
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    \21\ 40 CFR 51.309(d)(4)(v).
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G. Regulatory and Legal History of the 2014 Wyoming SIP and FIP

    On January 30, 2014, the EPA promulgated a final rule titled
``Approval, Disapproval and Promulgation of Implementation Plans; State
of Wyoming; Regional Haze State Implementation Plan; Federal
Implementation Plan for Regional Haze'' approving, in part, a regional
haze SIP revision submitted by the State of Wyoming on January 12,
2011.\22\ In the final rule, the EPA also disapproved, in part, the
Wyoming regional haze SIP, including the SIP NOX BART
emission limit of 0.21 lb/MMBtu (30-day rolling average) for each of
the three Laramie River Units, and promulgated a FIP that imposed a
NOX BART emission limit of 0.07 lb/MMBtu (30-day rolling
average) at each of the three Laramie River Units, among other actions.
The Laramie River Station is in Platte County, Wyoming, and is
comprised of three 550 megawatt (MW) dry-bottom, wall-fired boilers
(Units 1, 2, and 3) burning subbituminous coal for a total net
generating capacity of 1,650 MW. All three units are within the
statutory definition of BART-eligible units, were determined to be
subject to BART by WY, approved in the SIP and are operated by, and
owned in part by, Basin Electric Power Cooperative (Basin Electric).
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    \22\ 79 FR 5032 (January 30, 2014).
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    Basin Electric, the State of Wyoming, and others challenged the
final rule. Basin Electric challenged our action as it pertained to the
NOX BART emission limits for Laramie River Units 1-3.\23\
After mediated discussions through the U.S. Court of Appeals for the
Tenth Circuit's Mediation Office, Basin Electric, Wyoming and the EPA
reached a settlement in 2017 that if fully implemented, would address
all of Basin Electric's challenges to the 2014 final rule and Wyoming's
challenges to the portion of the 2014 final rule establishing
NOX BART emission limits for Laramie River Units 1-
3.24 25
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    \23\ Basin Electric Cooperative v. EPA, No. 14-9533 (10th Cir.
March 31, 2014) and Wyoming v. EPA, No. 14-9529 (10th Cir. March 28,
2014).
    \24\ 81 FR 96450 (December 30, 2016).
    \25\ Letter from Eileen T. McDonough, U.S. Department of
Justice, to Elizabeth Morrisseau, Wyoming Attorney General's Office,
and Christina F. Gomez, Denise W. Kennedy, and Patrick R, Day,
Holland & Hart LLC (notification that both EPA and the Department of
Justice (DOJ) determined not to withdraw their consent to the
Settlement Agreement) (April 24, 2017); Settlement Agreement between
Basin Electric Power Cooperative, the State of Wyoming, and the EPA
(April 24, 2017); First Amendment to Settlement Agreement (pursuant
to Paragraph 15 of the Agreement, extended the deadline for EPA to
determine whether to withdraw or consent to the Settlement Agreement
in Paragraph 1 to May 3, 2017); Second Amendment to Settlement
Agreement (pursuant to Paragraph 15 of the Agreement, amended the
date in Paragraph 5.b.ii. for the SO2 emission limits for
Laramie River Units 1 and 2 to commence December 31, 2018)
(September 14, 2018).
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    The settlement agreement requires the EPA to propose a FIP revision
to include three major items:
     First, an alternative (BART alternative) to the
NOX BART emission limits in the EPA's 2014 FIP that
includes:
    [cir] NOX emission limits for Laramie River Units 2 and
3 of 0.15 lb/MMBtu (30-day rolling average) commencing December 31,
2018, with an interim limit of 0.18 lb/MMBtu (30-day rolling average)
commencing the date that the EPA's final revised FIP becomes effective
and ending December 31, 2018; and
    [cir] a SO2 emission limit for Laramie River Units 1 and
2 of 0.12 lb/MMBtu (annual) averaged annually across the two units
commencing December 31, 2018.
     Second, a NOX BART emission limit for Laramie
River Unit 1 of 0.06 lb/MMBtu on a 30-day rolling average commencing
July 1, 2019, with an interim limit of 0.18 lb/MMBtu on a 30-day
rolling average commencing the date that the EPA's final revised FIP
becomes effective and ending June 30, 2019. These limits are
voluntarily requested by Basin Electric.
     Third, installation of SCR on Laramie River Unit 1 by July
1, 2019, (thereby revising the compliance date of the existing SIP) and
installation of SNCR on Units 2 and 3 by December 30, 2018.
    In accordance with other terms of the 2017 settlement, Wyoming also
submitted a SIP revision to the EPA on April 5, 2018, to revise the
SO2 annual reporting requirements for Laramie River Units 1
and 2 as they pertain to the backstop trading program under 40 CFR
51.309. Specifically, Wyoming determined that Basin Electric must use
SO2 emission rates of 0.159 lb/MMBtu for Laramie River Unit
1 and 0.162 lb/MMBtu for Laramie River Unit 2, and multiply those rates
by the actual annual heat input during the year for each unit to
calculate and report emissions under the SO2 backstop
trading program. The revisions, as described in Section III., ensure
that SO2 emissions reductions proposed under the 2017
settlement agreement are no longer counted as reductions under the
backstop trading program.
    The EPA is required, per the 2017 settlement agreement, to sign a
proposed rule no later than 6 months after receipt of Wyoming's SIP
submittal.

III. Proposed FIP Revisions

A. Background

    In the 2011 submittal, Wyoming determined that emission limits for

Laramie River Units 1-3 of 0.23 lb/MMBtu (30-day rolling average) each,
reflecting installation of operation of new low NOX burners
(LNB) with overfire air (OFA), were reasonable measures to satisfy the
units NOX BART obligations. We disagreed with Wyoming that
LNB with OFA was reasonable for NOX BART and subsequently
finalized a FIP on January 30, 2014, with NOX BART emission
limits of 0.07 lb/MMBtu (30-day rolling average) for each unit based on
the installation and operation of new LNBs with OFA and SCR. The 2017
settlement agreement, described previously in Section II.G, established
a deadline for the EPA to take specific actions related to the
NOX emission limits established in the 2014 FIP for Laramie
River Units 1-3 as well as new SO2 emission limits and
emission control technologies requirements.

B. The BART Alternative

    We are proposing to amend the 2014 FIP to replace the
NOX BART requirements with a NOX BART
alternative. Specifically, we are proposing to revise the
NOX emission limits for Laramie River Units 2 and 3 and
establish a SO2 emission limit for Units 1 and 2. We
evaluate the NOX BART alternative against the regulatory
BART alternative requirements found in 40 CFR 51.308(e)(2) of the
regional haze regulations.
    The RHR establishes requirements for BART alternatives. Three of
the requirements are of relevance to our evaluation of the BART
alternative. We evaluate the proposed BART alternative to the
NOX BART requirements in the EPA's 2014 FIP with respect to
each of these following elements:
     A demonstration that the emissions trading program or
other BART alternative measure will achieve greater reasonable progress
than would have resulted from the installation and operation of BART at
all sources subject to BART in the state and covered by the BART
alternative program.\26\
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    \26\ 40 CFR 51.308(e)(2)(i).
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     A requirement that all necessary emissions reductions take
place during the period of the first long-term strategy for regional
haze.\27\
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    \27\ 40 CFR 51.308(e)(2)(iii).
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     A demonstration that the emissions reductions resulting
from the BART alternative measure will be surplus to those reductions
resulting from the measures adopted to meet requirements of the CAA as
of the baseline date of the SIP.\28\
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    \28\ 40 CFR 51.308(e)(2)(iv).
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    1. Demonstration that the BART alternative measure will achieve
greater reasonable progress.
    Pursuant to 40 CFR 51.308(e)(2)(i), we must demonstrate that the
BART alternative measure will achieve greater reasonable progress than
would have resulted from the installation and operation of BART at all
sources subject to BART in the state and covered by the BART
alternative program. For a source-specific BART alternative, the
critical elements of this demonstration are:
     A list of all BART-eligible sources within the state;
     A list of all BART-eligible sources and all BART source
categories covered by the BART alternative program;
     An analysis of BART and associated emission reductions;
     An analysis of projected emissions reductions achievable
through the BART alternative; and
     A determination that the BART alternative achieves greater
reasonable progress than would be achieved through the installation and
operation of BART.
    We summarize the proposed revisions to the 2014 FIP with respect to
each of these elements and provide our evaluation in the proceeding
sections.
    a. A list of all BART-eligible sources within the state.
    Table 1 shows a list of all the BART-eligible sources in the State
of Wyoming.\29\
---------------------------------------------------------------------------

    \29\ 77 FR 33029 (June 4, 2012).

                 Table 1--Wyoming BART-Eligible Sources
------------------------------------------------------------------------
                Company                             Facility
------------------------------------------------------------------------
PacifiCorp............................  Jim Bridger.
Basin Electric........................  Laramie River.
PacifiCorp............................  Dave Johnston.
PacifiCorp............................  Naughton.
PacifiCorp............................  Wyodak.
FMC...................................  Westvaco.
General Chemical......................  Green River.
Black Hills...........................  Neil Simpson 1.
Sinclair..............................  Sinclair Refinery.
Sinclair..............................  Casper Refinery.
FMC...................................  Granger.
Dyno Nobel............................  Dyno Nobel.
OCI Wyoming...........................  OCI Wyoming.
P4 Production.........................  P4 Production.
------------------------------------------------------------------------

    b. A list of all BART-eligible sources and all BART source
categories covered by the BART alternative program.
    Table 2 shows a list of all the BART-eligible sources covered by
the BART alternative program along with the BART source category.

                    Table 2--Wyoming Subject-to-BART Sources Covered by the BART Alternative
----------------------------------------------------------------------------------------------------------------
               Company                         Facility          Subject-to-BART units       Source category
----------------------------------------------------------------------------------------------------------------
Basin Electric.......................  Laramie River..........  Units 1-3..............  Electrical generating
                                                                                units.
----------------------------------------------------------------------------------------------------------------

    c. Analysis of BART and associated emission reductions
    Pursuant to 40 CFR 51.308(e)(2)(i)(C), the BART alternative must
include an analysis of BART and associated emission reductions at
Laramie River Units 1-3. As noted previously, the SIP and 2014 FIP each
included BART analyses and determinations for Units 1-3. Since we
disapproved Wyoming's BART NOX determinations for Laramie
River Units 1-3, we conducted our own BART analysis and determination
for NOX BART in the 2014 FIP.\30\ For the purposes of this
evaluation, we consider NOX BART for Laramie River Units 1-3
to be the 2014 FIP BART determination summarized in Table 3.
---------------------------------------------------------------------------

    \30\ 79 FR 5039 (January 30, 2014).

                     Table 3--Summary of the EPA's Laramie River Units 1-3 NOX BART Analysis
----------------------------------------------------------------------------------------------------------------
                                                                                Emission limit
                                                                                (lb/MMBtu) (30-    Emission
                    Unit                                 Technology *               day rolling      reduction
                                                                                average)          (tpy)
----------------------------------------------------------------------------------------------------------------
Unit 1.....................................  New LNBs with OFA and SCR..........            0.07           4,880
Unit 2.....................................  New LNBs with OFA and SCR..........            0.07           5,129

Unit 3.....................................  New LNBs with OFA and SCR..........            0.07           5,181
----------------------------------------------------------------------------------------------------------------
* The technology listed is the technology evaluated as BART, but sources can choose to use another technology or
  combination of technologies to meet established limits.

    As described previously, reductions in SO2 emissions
were previously accounted for under the SO2 backstop trading
program, per 40 CFR 51.309.
    d. Analysis of projected emissions reductions achievable through
the BART alternative
    To determine the projected emissions reductions achievable through
the BART alternative, the emissions are calculated using the same
process explained in the 2014 FIP, whereby a percent reduction is
applied to the Laramie River Units 1-3 baseline emissions. However, the
actual percent reduction for the BART alternative is different than the
2014 FIP because the controlled rates are different between the 2014
FIP and BART alternative. The percent reduction, for both the BART
alternative and the 2014 FIP, is calculated as the controlled annual
emission rate (in units of lb/MMBtu) divided by the annual average
emission rate (in units of lb/MMBtu) during the BART baseline period
(2001-2003). In the BART alternative, the modeled controlled
NOX annual emission rate for Unit 1, using SCR controls, is
0.04 lb/MMBtu (annual) based on the expected annual emission
performance under a 0.06 lb/MMBtu emission limit (30-day rolling
average). Likewise, the modeled controlled NOX annual
emission rate for Units 2 and 3, using LNB with OFA and SNCR, is 0.128
lb/MMBtu based on the expected annual emission performance as
calculated in the 2014 FIP under a 0.15 lb/MMBtu emission rate (30-day
rolling average). The controlled SO2 annual emission rate
for Units 1 and 2 is 0.115 lb/MMBtu (annual) for each unit based on the
expected annual emission performance under a 0.12 lb/MMBtu emission
limit (30-day rolling average).
    The controlled annual emissions rates are divided by the average
emission rates during the BART baseline period (2001-2003) to calculate
the percent reduction for each unit. The average emission rates during
the BART baseline period for each unit are: \31\
---------------------------------------------------------------------------

    \31\ Laramie River Station Power Plant Visibility Impacts for
Two Emissions Control Scenarios: Final Report. Prepared for Basin
Electric, AECOM (May 2016). Data based on the information obtained
from the EPA's Clean Air Markets Division (CAMD) database, available
at: https://ampd.epa.gov/ampd/ ampd/.
---------------------------------------------------------------------------

     Unit 1: 0.2585 lb NOX/MMBtu; 0.159 lb
SO2/MMBtu,
     Unit 2: 0.2703 lb NOX/MMBtu; 0.162 lb
SO2/MMBtu, and
     Unit 3: 0.2669 lb NOX/MMBtu.
    The percent reduction for each unit is applied to the baseline
emissions to determine the NOX and SO2 emission
reductions associated with the BART alternative for Laramie River Units
1-3 (Table 4).

                                     Table 4--Summary of the EPA's Laramie River Units 1-3 BART Alternative Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                NOX                             SO2
                                                                                ---------------------------------------------------------------
                                                                                Emission limit                  Emission limit
                      Unit                                      Technology                (lb/MMBtu) (30-    Emission     (lb/MMBtu) (30-    Emission
                                                                                day rolling      reduction      day rolling      reduction
                                                                                average)          (tpy)         average)          (tpy)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 1.........................................  New LNBs with OFA and SCR..............            0.06           4,880            0.12           1,032
Unit 2.........................................  New LNBs with OFA and SNCR.............            0.15           3,342            0.12           1,091
Unit 3.........................................  New LNBs with OFA and SNCR.............            0.15           3,337              NA              NA
--------------------------------------------------------------------------------------------------------------------------------------------------------
NA = not applicable.

    e. Determination that the BART alternative achieves greater
reasonable progress than would be achieved through the installation and
operation of BART.
    Pursuant to 40 CFR 51.308(e)(2)(i)(E), the FIP revision must
provide a determination under 40 CFR 51.308(e)(3) or otherwise based on
the clear weight of evidence that the BART alternative achieves greater
reasonable progress than BART. Two different tests for determining
whether the BART alternative achieves greater reasonable progress than
BART are outlined in 40 CFR 51.308(e)(3). Under the first test, if the
distribution of emissions is not substantially different than under
BART, and the BART alternative measure results in greater emission
reductions, then the BART alternative measure may be deemed to achieve
greater reasonable progress. Under the second test, if the distribution
of emissions is significantly different, then dispersion modeling must
be conducted to determine differences between BART and the BART
alternative for each impacted Class I area for the worst and best 20
percent days. The modeling results would demonstrate ``greater
reasonable progress'' if both of the following criteria are met: (1)
Visibility does not decline in any Class I area; and (2) there is an
overall improvement in visibility, determined by comparing the average
differences between BART and the BART alternative over all affected
Class I areas. This modeling test is sometimes referred to as the
``two-prong test.''
    For the proposed FIP revision, we determined that the BART
alternative will not achieve greater emissions reductions than BART
because, while the SO2 emission reductions for Units 1 and 2
(1,032 tons per year (tpy) and 1,091 tpy respectively under the BART
alternative, compared to 0 tpy under BART) and NOX emission
reduction for Unit 1 (5,179 tpy under the BART

alternative compared to 4,880 tpy under BART) are greater under the
BART alternative, the NOX emission reductions under the BART
alternative are less for Units 2 and 3 (3,342 lb/MMBtu and 3,337 lb/
MMBtu, respectively) than the NOX emission reductions under
BART (5,129 lb/MMBtu and 5,181 lb/MMBtu, respectively). Therefore, we
evaluated the results of modeling (using the Comprehensive Air Quality
Model with Extensions (CAMx) model version 5.41\32\) performed by a
contractor for Basin Electric, AECOM, to assess whether the BART
alternative would result in ``greater reasonable progress'' under the
two-prong test in 40 CFR 51.308(e)(3).\33\
---------------------------------------------------------------------------

    \32\ CAMx modeling software (http://www.camx.com/download/default.aspx) and User's Guide (http://www.camx.com/about/default.aspx) are available on these CAMx web pages.
    \33\ Laramie River Station Power Plant Visibility Impacts for
Two Emissions Control Scenarios: Final Report. Prepared for Basin
Electric, AECOM (May 2016).
---------------------------------------------------------------------------

    CAMx has a scientifically current treatment of chemistry to
simulate transformation of emissions into visibility-impairing
particles of species such as ammonium nitrate and ammonium sulfate, and
is often employed in large-scale modeling when many sources of
pollution and/or long transport distances are involved. Photochemical
grid models like CAMx include all emissions sources and have realistic
representation of formation, transport, and removal processes of the
particulate matter that causes visibility degradation. The use of the
CAMx model for analyzing potential cumulative air quality impacts has
been well established: The model has been used for previous visibility
modeling studies in the U.S., including SIPs.\34\
---------------------------------------------------------------------------

    \34\ 82 FR 46903 (October 10, 2017) (Final action for the
Coronado Generating Station in the Regional Haze Plan for Arizona);
81 FR 296 (January 5, 2016) (Final action for Texas and Oklahoma
Regional Haze Plans).
---------------------------------------------------------------------------

    The modeling followed a modeling protocol that was reviewed by the
EPA.\35\ The starting point for assessing visibility impacts for
different levels of emissions from Laramie River was the Three-State
Air Quality Modeling Study (3SAQS) modeling platform that provides a
framework for addressing air quality impacts in Colorado, Utah and
Wyoming. The 3SAQS is a publicly available platform intended to
facilitate air resources analyses.\36\ The 3SAQS developed a base year
modeling platform using the year 2008 to leverage work completed during
the West-wide Jump-start Air Quality modeling study (WestJump).\37\ For
the Laramie River modeling, AECOM performed additional modeling to
refine the modeling domain from the 3SAQS 12-kilometer (km) grid
resolution to a finer 4-km grid resolution. The refined spatial
resolution was used to more accurately simulate the concentration
gradients of gas and particulate species in the plumes emitted from the
source facilities. The AECOM modeling data sets used for this action
are available in the docket.\38\ For the two-prong test, an existing
projected 2020 emissions database was used to estimate emissions of
sources within the modeling domains. The existing 2020 database was
derived from the 3SAQS study, which projected emissions from 2008 to
2020. Since the BART alternative emissions reductions will not be fully
in place until the end of 2018, the 2020 emissions projections are more
representative of the air quality conditions that will be obtained
while the BART alternative is being implemented than the 2008 database.
In the three 2020 CAMx modeling scenarios, Laramie River emissions were
modeled to represent the baseline, the BART 2014 FIP, and the proposed
BART alternative as described in the proceeding section and Table 5.
---------------------------------------------------------------------------

    \35\ Photochemical Modeling Protocol for the Visibility
Assessment of Basin Electric Laramie River Power Plant. Prepared for
Basin Electric, AECOM (September 2015). Draft Modeling Guidance for
Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and
Regional Haze, EPA (December 3, 2014).
    \36\ Three-State Air Quality Modeling Study CAMx Photochemical
Grid Model Final Model Performance Evaluation. University of North
Carolina and Environ (September 2014). http://views.cira.colostate.edu/wiki/Attachments/Modeling/3SAQS_Base08b_MPE_Final_30Sep2014.pdf.
    \37\ https://www.wrapair2.org/WestJumpAQMS.aspx. Additional
information on the WestJump study available in the docket for this
action, ``WestJump Fact Sheet.''
    \38\ CAMx modeling data available on hard disk in the docket.
---------------------------------------------------------------------------

    The CAMx-modeled concentrations for sulfur, nitrogen, and primary
particulate matter (PM) were tracked using the CAMx Particulate Source
Apportionment Technology (PSAT) tool \39\ so that the concentrations
and visibility impacts due to Laramie River could be separated out from
those due to the total of all other modeled sources. AECOM computed
visibility impairment due to Laramie River using the EPA's Modeled
Attainment Test Software (MATS) tool which bias-corrects CAMx outputs
to available measurements of PM species and uses the revised IMPROVE
equation to calculate the 20 percent best and 20 percent worst days for
visibility impacts.\40\
---------------------------------------------------------------------------

    \39\ PSAT is included in the CAMx modeling code and is described
in the CAMx User's Guide available at: http://www.camx.com/download/default.aspx.
    \40\ IMPROVE refers to a monitoring network and also to the
equation used to convert monitored concentrations to visibility
impacts. ``Revised IMPROVE Algorithm for Estimating Light Extinction
from Particle Speciation Data'', IMPROVE technical subcommittee for
algorithm review (January 2006). http://vista.cira.colostate.edu/Improve/gray-literature/.
---------------------------------------------------------------------------

    As described previously, the CAMx system was configured using the
3SAQS modeling platform to simulate future year 2020 conditions for the
following modeling scenarios:
     Baseline: This scenario included the actual emission rates
for all three units during the 2001-2003 BART baseline period that were
previously modeled in CALPUFF simulations.
     BART: This scenario included the emission rates for all
three units that correspond to the EPA's 2014 FIP.
     BART alternative: This scenario included the emission
rates for all three units that correspond to the BART alternative.
    The only differences among scenarios are the NOX and
SO2 emission rates for Laramie River (Table 5). All other
model inputs, including other regional emission sources, remained
unchanged among all future year scenarios.

                       Table 5--Laramie River Units 1-3 Emissions for the CAMx Model by Scenario Projected to Year 2020 Conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                PM2.5 (tpy)
                Scenario                     NOX (tpy)       SO2 (tpy)       VOC (tpy)       CO (tpy)       PM10 (tpy)                       NH3 (tpy)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline................................          18,890          11,605             234           1,950           2,748           2,440              41
BART....................................           3,560          11,605             234           1,950           2,748           2,440              41
BART alternative........................           7,030           9,479             234           1,950           2,748           2,440              41
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Maintaining consistent model inputs allows the CAMx modeling
results to be easily compared to analyze the effects of different
emissions control scenarios. As described previously, the PSAT was
applied to the simulations to track and account for the particulate
mass concentrations that originate or are formed as a result of
emissions from Laramie River.
    Once all the scenarios above were simulated with the photochemical
grid model, model results were post-processed to isolate the changes to
visibility conditions as a result of emissions controls applied to
Laramie River Units 1-3 under the scenarios described previously. To
assess compliance with the RHR requirements, visibility changes are
assessed during the 20 percent best visibility days and the 20 percent
worst visibility days at each potentially affected federally regulated
Class I area. Model-predicted visibility impacts at the thirteen Class
I areas in the 4-km modeling domain were estimated for each of the
three future year modeling scenarios.
    The MATS tool was used to convert model concentrations into
visibility estimates and account for quantifiable model bias. All
models are affected by biases, i.e., model results simulate complex
natural phenomena and, as such, model results can either over or under
estimate measured concentrations. The use of MATS helps mitigate model
bias by pairing model estimates of PM species concentrations with
actual measured conditions.
    As a final step, Laramie River's visibility impact under the BART
alternative is compared to the visibility impact under the Baseline and
BART scenarios to determine if the BART alternative meets the
requirements of the two-prong test, i.e., prong 1, no degradation
compared to the Baseline at any Class I area on the best visibility
days, and prong 2, greater progress compared to BART averaged over all
Class I areas on the worst visibility days.
    The visibility impacts derived from modeling results are summarized
in Tables 6 and 7. The tables show the projected Laramie River
contribution to visibility on the 20 percent best days and worst days,
respectively, for the 2020 Baseline (Column A), BART (Column B), and
BART alternative (Column C) scenarios at each of the Class I areas
analyzed. The last two columns show the predicted visibility benefits
from the BART alternative scenario relative to both the 2020 baseline
(Column D) and BART (Column E). Also shown at the bottom row are the
average visibility values from all the areas. Negative values in Column
D indicate that the BART alternative scenario has smaller contributions
to visibility relative to the baseline (``prong 1''), and therefore it
improves visibility over the baseline. Similarly, negative values in
Column E indicate that the BART alternative scenario has smaller
contributions to visibility relative to the BART scenario (``prong
2'').

      Table 6--Laramie River Visibility Impact (Units 1-3) for the 2020 Baseline, BART, and BART Alternative Scenarios on the 20 Percent Best Days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                [C] BART
                        Class I area *                           [A] Baseline    [B] BART (dv)    alternative   [D] BART alternative--      [E] BART
                                                                     (dv)                            (dv)              Baseline        alternative--BART
--------------------------------------------------------------------------------------------------------------------------------------------------------
Badland NP....................................................          0.0212          0.0131          0.0138             -0.0074               0.0007
Bridger WA....................................................          0.0000          0.0000          0.0000              0.0000               0.0000
Fitzpatrick WA................................................          0.0000          0.0000          0.0000              0.0000               0.0000
Grand Teton NP................................................          0.0012          0.0012          0.0009             -0.0003              -0.0003
Mount Zirkel WA...............................................          0.0000          0.0000          0.0000              0.0000               0.0000
North Absaroka WA **..........................................          0.0005          0.0005          0.0004             -0.0001              -0.0001
Rawah WA......................................................          0.0000          0.0000          0.0000              0.0000               0.0000
Red Rock Lakes WA.............................................          0.0012          0.0012          0.0009             -0.0003              -0.0003
Rocky Mountain NP.............................................          0.0000          0.0000          0.0000              0.0000               0.0000
Teton WA......................................................          0.0012          0.0012          0.0009             -0.0003              -0.0003
Washakie WA **................................................          0.0005          0.0005          0.0004             -0.0001              -0.0001
Wind Cave NP..................................................          0.0055          0.0051          0.0047             -0.0008              -0.0004
Yellowstone NP................................................          0.0012          0.0012          0.0009             -0.0003              -0.0003
All Class I Area Average ***..................................          0.0025         0.00185         0.00176                  NA             -0.00009
--------------------------------------------------------------------------------------------------------------------------------------------------------
* NP = National Park; WA = Wilderness Area.
** Values reported for these Class I areas have been calculated with only 2 years of valid monitoring data.
*** The average visibility impact is calculated as the sum of the visibility impacts divided by the number of Class I areas.
**** NA = Not applicable.

      Table 7--Laramie River Visibility Impact (Units 1-3) for the 2020 Baseline, BART, and BART Alternative Scenarios on the 20 Percent Worst Days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                [C] BART
                        Class I area *                           [A] Baseline    [B] BART (dv)    alternative   [D] BART alternative--      [E] BART
                                                                     (dv)                            (dv)              Baseline        alternative--BART
--------------------------------------------------------------------------------------------------------------------------------------------------------
Badland NP....................................................          0.0259          0.0177          0.0176             -0.0083              -0.0001
Bridger WA....................................................          0.0029          0.0028          0.0023             -0.0006              -0.0005
Fitzpatrick WA................................................          0.0029          0.0028          0.0023             -0.0006              -0.0005
Grand Teton NP................................................          0.0024          0.0023          0.0019             -0.0005              -0.0004
Mount Zirkel WA...............................................          0.0065          0.0059          0.0053             -0.0012              -0.0006
North Absaroka WA **..........................................          0.0003          0.0003          0.0001             -0.0002              -0.0002
Rawah WA......................................................          0.0065          0.0059          0.0053             -0.0012              -0.0006
Red Rock Lakes WA.............................................          0.0024          0.0023          0.0019             -0.0005              -0.0004
Rocky Mountain NP.............................................          0.0137          0.0119          0.0106             -0.0031              -0.0013
Teton WA......................................................          0.0024          0.0023          0.0019             -0.0005              -0.0004
Washakie WA **................................................          0.0003          0.0003          0.0001             -0.0002              -0.0002

Wind Cave NP..................................................          0.0369          0.0267          0.0253             -0.0116              -0.0014
Yellowstone NP................................................          0.0024          0.0023          0.0019             -0.0005              -0.0004
All Class I Area Average......................................         0.00812         0.00642         0.00589                  NA             -0.00054
--------------------------------------------------------------------------------------------------------------------------------------------------------
* NP = National Park; WA = Wilderness Area.
** Values reported for these Class I areas have been calculated with only 2 years of valid monitoring data.
*** NA = Not applicable.

    Table 6 shows that the proposed BART alternative emissions will not
result in degradation of visibility on the 20 percent best days
compared to the 2020 baseline conditions at any of the 13 analyzed
Class I areas. In each individual area, visibility is predicted to
improve or remain unchanged compared to the 2020 baseline visibility
since all values shown in Column D are either negative or zero.
Overall, the BART alternative scenario shows an average improvement in
visibility of 0.00009 deciviews (dv) relative to BART for the best 20
percent days. Table 6 also shows that for the BART alternative
scenario, visibility during the best days improves or remains unchanged
at all Class I areas compared to the BART scenario except for Badlands
National Park.
    Table 7 shows that the proposed BART alternative emissions will not
result in degradation of visibility on the 20 percent worst days
compared to the 2020 baseline conditions at any of the 13 analyzed
Class I areas. In each individual area, visibility is predicted to
improve compared to the 2020 baseline visibility, since all values in
Column D are negative. Overall, the BART alternative shows an average
improvement in visibility of 0.00054 dv relative to BART for the 20
percent worst days. Table 7 also shows that for the BART alternative
scenario, visibility during the 20 percent worst days improves at all
Class I areas compared to the BART scenario.
    Pursuant to 40 CFR 51.309(e)(3), the modeling demonstrates
``greater reasonable progress'' if both of the following criteria are
met: (1) Visibility does not decline in any Class I area; and (2) there
is an overall improvement in visibility, determined by comparing the
average differences between BART and the BART alternative over all
affected Class I areas. For the first prong of the modeling test, the
modeling results show that visibility improves or stays the same (i.e.,
does not decline) under the BART alternative scenario for all Class I
areas for the 20 percent best and 20 percent worst days when compared
with the baseline scenario (Column D in Tables 6 and 7). For the second
prong of the modeling test, the modeling results show that there is an
overall improvement in visibility under the BART alternative scenario
for all Class I areas averaged over the 20 percent best and 20 percent
worst days when compared with the BART scenario (Column E in Tables 6
and 7). Based on the modeling analysis, we propose to find that the
BART alternative would achieve greater reasonable progress than BART
under 40 CFR 51.308(e)(3).
    Additionally, AECOM used PSAT to further evaluate the modeling to
determine whether the results represent ``real'' modeled visibility
differences and not the result of numerical artifacts or ``noise'' in
the model results. The numerical method used to simulate aerosol
thermodynamics in CAMx may be subject to some level of numerical error
when calculating the difference between two model simulations. This
typically occurs in areas with high concentrations of sulfate and
nitrate, and numerical error is manifested as areas of small random
checkerboard increases and decreases in concentrations, as illustrated
in the AECOM final report, Figure A-1, left panels.\41\ Note that this
numerical error is typically a very small percentage of the total
modeled nitrate and sulfate concentration. However, this error can be
relatively large in comparison to the impacts of a single emissions
source such as the Laramie River Station. The PSAT-based evaluation
approach eliminates numerical error in the model results by using model
tracer species that track the emissions and chemical transformation of
SO2 and NOX from a single source. By calculating
the changes in the PSAT mass attributed to Laramie River Station in the
baseline for the 2014 FIP and BART alternative simulations, the effects
of numerical error in other emissions sources are excluded from the
analysis of the Laramie River Station impacts. The AECOM report Figure
A-1, right panels, shows the nitrate mass attributed to the Laramie
River Station and illustrates that numerical error from other sources
is eliminated using this approach. Thus, the PSAT plots show that
concentrations within the modeling domain are attributable to the
emissions from Laramie River, and therefore provide reliable data for
assessing whether there is a numerical difference between the
visibility benefits from the BART and BART alternative control
scenarios.
---------------------------------------------------------------------------

    \41\ Laramie River Station Power Plant Visibility Impacts for
Two Emissions Control Scenarios: Final Report. Prepared for Basin
Electric, AECOM (May 2016).
---------------------------------------------------------------------------

    Finally, we note that 40 CFR 51.308(e)(3) allows for a straight
numerical test, regardless of the magnitude of the computed
differences. The regulation does not specify a minimum delta deciview
difference between the modeled scenarios that must be achieved in order
for a BART alternative to be deemed to achieve greater reasonable
progress than BART. Accordingly, given that the modeling results show
that visibility under the BART alternative does not decline at any of
the 13 affected Class I areas compared to the baseline (prong 1) and
will result in improved visibility, on average, across all 13 Class I
areas compared to BART in the 2014 FIP (prong 2), we propose to find
that the BART alternative will achieve greater reasonable progress than
BART (2014 FIP) under the two-prong modeling test in 40 CFR
51.308(e)(3).
    2. A requirement that all necessary emissions reductions take place
during the period of the first long-term strategy for regional haze.
    Pursuant to 40 CFR 51.308(e)(2)(iii), all necessary emission
reductions must take place during the period of the first long-term
strategy for regional haze. The RHR further requires a detailed
description of the BART alternative measure, including schedules for
implementation, the emission reductions required by the program, all
necessary administrative and technical

procedures for implementing the program, rules for accounting and
monitoring emissions, and procedures for enforcement.\42\
---------------------------------------------------------------------------

    \42\ 40 CFR 51.308(e)(2)(iii).
---------------------------------------------------------------------------

    As noted previously, the 2017 settlement agreement includes
requirements for implementing the BART alternative. In addition to the
emission limitations for NOX and SO2, the 2017
settlement agreement includes compliance dates, interim limits,
averaging times, and control technology requirements. The monitoring,
recordkeeping, and reporting requirements,\43\ along with other aspects
of the 2014 FIP that are not contained within the 2017 settlement
agreement, remain unchanged in the EPA's FIP.\44\ The compliance date
for the BART alternative is December 31, 2018, for Laramie River Units
2 and 3 to install and operate SNCR with corresponding NOX
emission limits of 0.15 lb/MMBtu (30-day rolling average).\45\ Laramie
River Units 2 and 3 must also meet interim NOX emission
limits of 0.18 lb/MMBtu (30-day rolling average; each) commencing the
date that the EPA's final revised FIP becomes effective and ending on
December 30, 2018.\46\ In addition, Laramie River Units 1 and 2 must
meet an SO2 emission limit of 0.12 lb/MMBtu averaged
annually across the two units commencing on December 31, 2018.\47\
Therefore, we propose to find that the proposed FIP revision along with
the existing FIP provisions will ensure that all necessary emission
reductions take place during the period of the first long-term strategy
and therefore meets the requirements of 40 CFR 51.308(e)(2)(iii).
---------------------------------------------------------------------------

    \43\ 40 CFR 52.2636(e)-(h).
    \44\ 40 CFR 52.2636.
    \45\ Settlement Agreement between Basin Electric Power
Cooperative, the State of Wyoming and the EPA (April 24, 2017).
    \46\ Ibid.
    \47\ Second Amendment to Settlement Agreement (pursuant to
Paragraph 15 of the Agreement, amended the date in Paragraph 5.b.ii.
for the SO2 emission limits for Laramie River Units 1 and
2 to commence December 31, 2018) (September 14, 2018).
---------------------------------------------------------------------------

    3. Demonstration that emissions reductions from the BART
alternative measure will be surplus.
    Pursuant to 40 CFR 51.308(e)(2)(iv), the SIP (or FIP) must
demonstrate that the emissions reductions resulting from the BART
alternative measure will be surplus to those reductions resulting from
measures adopted to meet requirements of the CAA as of the baseline
date of the SIP. The baseline date for regional haze SIPs is 2002. All
the NOX emission reductions required by the BART alternative
are surplus to reductions resulting from SIP measures applicable to
Laramie River as of 2002. In addition, the proposed SIP revision
discussed in Section IV, revises the SO2 emissions reporting
requirements for Laramie River Units 1 and 2 so that the SO2
emissions reductions achieved from the 2017 settlement agreement are
not also counted towards reductions under the SO2 backstop
trading program and thereby included in the regional SO2
milestone. As discussed in Section IV, we propose to approve these
changes to the SIP. Therefore, we propose to find that the BART
alternative complies with 40 CFR 51.308(e)(2)(iv). In sum, we propose
to find that the BART alternative meets all the applicable requirements
of 40 CFR 51.308(e)(2).
    Finally, in accordance with the proposed establishment of
SO2 emission limits in the proposed FIP for Laramie River
Units 1 and 2, we also propose to revise the monitoring, recordkeeping,
and reporting requirements of the 2014 FIP to reflect the establishment
of SO2 emission limits in the proposed FIP. These proposed
revisions support CAA section 110(a)(2)(A) requiring implementation
plans to include enforceable emission limitations. In order to be
considered enforceable, emission limits must include associated
monitoring, recordkeeping, and reporting requirements. In addition, the
CAA and the EPA's implementing regulations expressly require
implementation plans to include regulatory requirements related to
monitoring, recordkeeping, and reporting for applicable emissions
limitations.\48\ We do not propose to alter the monitoring, record
keeping, and reporting requirements established in the 2014 FIP that
relate to compliance with the BART emission limit for NOX.
---------------------------------------------------------------------------

    \48\ See, e.g. CAA section 110(a)(2)(F) and 40 CFR 51.212(c).
---------------------------------------------------------------------------

C. The NOX Emission Limit for Laramie River Unit 1

    In addition to the BART alternative, we are also proposing to amend
the 2014 FIP by revising the NOX emission limit for Laramie
River Unit 1 as voluntarily requested by Basin Electric in the
settlement agreement.\49\ The amendment revises the NOX
emission limit for Unit 1 from the NOX BART limit of 0.07
lb/MMBtu to 0.06 lb/MMBtu (30-day rolling average) commencing July 1,
2019, with an interim limit of 0.18 lb/MMBtu (30-day rolling average)
commencing the effective date of the EPA's final revised FIP and ending
June 30, 2019. Because the revision to the NOX emission
limit for Laramie River Unit 1 achieves greater NOX emission
reductions than the relevant portions of the 2014 FIP, we propose to
amend the Wyoming regional haze 2014 FIP with this revision.
---------------------------------------------------------------------------

    \49\ Settlement Agreement between Basin Electric Power
Cooperative, the State of Wyoming and the EPA (April 24, 2017).
---------------------------------------------------------------------------

IV. Proposed Action on Submitted SIP Revisions

A. Background

    Wyoming submitted SIP revisions on January 12, 2011, and April 19,
2012, that address regional haze requirements under 40 CFR 51.309. As
explained previously, 40 CFR 51.309 allows certain western Transport
Region States an optional way to fulfill regional haze requirements as
opposed to adopting the requirements under 40 CFR 51.308. As required
by 40 CFR 51.309, the participating states must adopt a trading
program, or what has been termed the Western Backstop Sulfur Dioxide
Trading Program (backstop trading program or trading program). One of
the components of the backstop trading program is for stationary source
SO2 emissions reductions.\50\ Thus, under 40 CFR 51.309,
states can satisfy the section 308 SO2 BART requirements by
adopting SO2 emissions milestones and a backstop trading
program. Under this approach, states must establish declining
SO2 emissions milestones for each year of the program
through 2018. If the milestones are exceeded in any year, the backstop
trading program is triggered.
---------------------------------------------------------------------------

    \50\ 40 CFR 51.309(d)(4).
---------------------------------------------------------------------------

    Among other things, the January 2011 and April 2012 SIP submittals
contained amendments to the Wyoming Air Quality Standards and
Regulations (WAQSR) Chapter 14, Emission Trading Program Regulations,
Section 3, Sulfur dioxide milestone inventory. On December 12, 2012, we
approved these amendments into the SIP as meeting the requirements of
40 CFR 51.309.\51\
---------------------------------------------------------------------------

    \51\ 77 FR 73926 (December 12, 2012).
---------------------------------------------------------------------------

B. April 5, 2018 Submittal

    On April 5, 2018, Wyoming submitted a SIP revision containing
amendments to WAQSR, Chapter 14, Emission Trading Program Regulations,
Section 3, Sulfur dioxide milestone inventory and additions to the
regional haze narrative.\52\ The amendments modify the SO2
emissions backstop trading program reporting requirements for Laramie
River Station Units 1 and 2. The revisions ensure that SO2
emissions reductions proposed under the 2017 settlement are no longer
counted as

reductions under the backstop trading program. Specifically, the
amendments revise the SO2 emissions reporting requirements
for Laramie River Units 1 and 2 so that Unit 1's SO2
emissions shall be reported based on an annual emission rate of 0.159
lb/MMBtu multiplied by the actual annual heat input, and Unit 2's
SO2 emissions shall be reported based on an annual emission
rate of 0.162 lb/MMBtu multiplied by the actual heat input. Annual
SO2 emissions for Laramie River Unit 3 shall be reported as
otherwise provided in Chapter 14, Section 3(b). The revisions also
require that the revised SO2 emissions reporting
requirements for Units 1 and 2 commence as of the year that Basin
Electric commences operation of SCR at Unit 1 and that Wyoming use the
revised SO2 emissions reporting requirements for all
purposes under Chapter 14. The additions to the SIP narrative provide
an explanation of the regulatory amendments. The Wyoming Environmental
Quality Council approved the proposed revisions on December 5, 2017
(effective February 5, 2018).
---------------------------------------------------------------------------

    \52\ State of Wyoming. Addressing Regional Haze Visibility
Protection For The Mandatory Federal Class I Areas Required Under 40
CFR 51.309. Revised April 5, 2018.
---------------------------------------------------------------------------

C. The EPA's Evaluation of the SO2 Emissions Reporting
Amendments

    We are proposing to approve Wyoming's amendments to the
SO2 emissions reporting requirements and the addition to the
SIP narrative for Laramie River Units 1 and 2, including when Basin
Electric is required to use the revised SO2 emissions
reporting requirements and how the SO2 emissions will be
reported within the context of the SO2 emissions milestone
inventory. Together, these revisions ensure that the SO2
emissions reductions in the BART alternative are not ``double-counted''
in the backstop trading program in order to meet the requirement in 40
CFR 51.308(e)(2)(iv) (requirement that emissions reductions from the
alternative will be surplus to the SIP). We evaluated how these
revisions meet the relevant requirements under 40 CFR 51.309(d)(4).
    We agree with Wyoming that the revisions to the SO2
emissions reporting requirements for Laramie River Units 1 and 2 are
sufficient to ensure that the SO2 emissions reductions
obtained under the settlement agreement under the NOX BART
alternative (see Section III) are not also counted towards reductions
under the SO2 backstop trading program milestones.\53\ The
annual SO2 emission rates of 0.159 lb/MMBtu and 0.162 lb/
MMBtu (30-day average) for Laramie River Units 1 and 2, respectively,
reflect the actual average emission rates from 2001 to 2003 for these
units.\54\ By reporting SO2 emissions using the average
annual SO2 emission rates from 2001 to 2003 (and multiplied
by the actual annual heat input) instead of reporting the actual
average annual SO2 emission rates, emissions reductions
achieved since the baseline period at these units will no longer be
included in the backstop trading program. Thus, if EPA decides to
finalize this proposed action, instead of reporting the actual annual
SO2 emissions for Units 1 and 2 achieved under the revised
average annual emission limit of 0.115 lb/MMBtu (0.12 lb/MMBtu; 30-day
rolling average limit), pursuant to 40 CFR 51.309(d)(4)(vi)(A) and the
settlement agreement, as of the year that Basin Electric commences
operation of SCR on Unit 1, SO2 emissions would be
calculated using the average annual emission rates reflective of the
baseline period (0.159 lb/MMBtu for Unit 1 and 0.162 lb/MMBtu for Unit
2) multiplied by the actual annual heat input. Thus, these revisions
not only ensure that the SO2 emissions reductions achieved
under the NOX BART alternative are only accounted for under
the BART alternative, and not ``double-counted,'' but also describe how
compliance with the backstop trading program requirements will be
determined as required under 40 CFR 51.309(d)(4)(i).
---------------------------------------------------------------------------

    \53\ 40 CFR 51.309(d)(4)(i).
    \54\ Laramie River Station Power Plant Visibility Impacts for
Two Emissions Control Scenarios: Final Report. Prepared for Basin
Electric, AECOM (May 2016). Data based on the information obtained
from the EPA's Clean Air Markets Division (CAMD) database, available
at: https://ampd.epa.gov/ampd/ ampd/.
---------------------------------------------------------------------------

    Under 40 CFR 51.309(d)(4)(ii), documentation of the SO2
emission calculation methodology and any changes to the specific
methodology used to calculate the emissions at any emitting unit for
any year after the base year must be provided in the backstop trading
program implementation plan. The revisions in Wyoming's 2018 SIP
submittal: (1) Document the changes to the specific methodology used to
calculate and report SO2 emissions at Laramie River Units 1
and 2, including the annual average SO2 emission rates for
each unit and how to determine the actual annual heat rate (Chapter 14,
Section 3(d)); (2) specify that the revised methodology will commence
as of the year that SCR is operational on Unit 1 (Chapter 14, Section
3(d)(i)); and (3) clarify that the revisions to the SO2
emissions reporting methodology for Units 1 and 2 shall be used for all
purposes under Chapter 14, Emission Trading Program Regulations
(Chapter 14, Section 3(e)). Thus, the revisions meet the requirements
of 40 CFR 51.309(d)(4)(ii) because the amendments to the SO2
emissions reporting requirements provide for documentation of the
changes to the specific methodology used to calculate emissions at
Laramie River Units 1 and 2 for the relevant years after the base year,
and the amendments are contained within Wyoming's backstop trading
program implementation plan (Chapter 14, Section 3).
    Under 40 CFR 51.309(d)(4)(iii), the EPA-approved plan includes
provisions requiring the monitoring, recordkeeping, and annual
reporting of actual stationary source SO2 emissions within
the State, (Chapter 14, Section 3(b)). These requirements continue to
apply to the Laramie River Units 1 and 2 and were not modified in
Wyoming's 2018 SIP submittal. Likewise, the requirements found in 40
CFR 51.309(d)(4)(iv), 40 CFR 51.309(d)(4)(v) and 40 CFR
51.309(d)(4)(vi) pertaining to the market trading program and
provisions for the 2018 milestone were not modified in Wyoming's 2018
SIP submittal. Because the revisions to the SO2 emissions
reporting requirements for Laramie River Units 1 and 2 meet the
requirements of 40 CFR 51.309(d)(4) we propose to approve the SIP
revisions to Chapter 14, Section 3.

V. Clean Air Act Section 110(l)

    Under CAA section 110(l), the EPA cannot approve a plan revision
``if the revision would interfere with any applicable requirement
concerning attainment and reasonable further progress (as defined in
section 7501 of this title), or any other applicable requirement of
this chapter.'' \55\ We propose to find that these revisions satisfy
section 110(l). The previous sections of the notice explain how the
proposed FIP revision will comply with applicable regional haze
requirements and general implementation plan requirements such as
enforceability. Likewise, the SIP revision will also comply with
applicable regional haze requirements. With respect to

requirements concerning attainment and reasonable further progress, the
Wyoming Regional Haze SIP and FIP, as revised by this action, will
result in a significant reduction in emissions compared to historical
levels. In addition, the area where the Laramie River Station is
located is in attainment for all National Ambient Air Quality Standards
(NAAQS). Thus, the revisions will ensure a significant reduction in
NOX and SO2 emissions compared to historical
levels in an area that has not been designated nonattainment for the
relevant NAAQS at those current levels.
---------------------------------------------------------------------------

    \55\ 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 Clean Air Act.
---------------------------------------------------------------------------

VI. Consultation With FLMs

    There are seven (7) Class I areas in the State of Wyoming. The
United States Forest Service manages the Bridger Wilderness,
Fitzpatrick Wilderness, North Absaroka Wilderness, Teton Wilderness,
and Washakie Wilderness. The National Park Service manages the Grand
Teton National Park and Yellowstone National Park. The RHR grants the
FLMs, regardless of whether a FLM manages a Class I area within the
state, a special role in the review of regional haze implementation
plans, summarized in Section II.E of this preamble.
    There are obligations to consult on plan revisions under 40 CFR
51.308(i)(3). Thus, we consulted with the Forest Service, the Fish and
Wildlife Service and the National Park Service on the proposed FIP
revision. We described the proposed revisions to the regional haze 2014
FIP and 2018 SIP revisions with the Forest Service, the Fish and
Wildlife Service and the National Park Service on August 15, 2018 and
met our obligations under 40 CFR 51.308(i)(3).

VII. The EPA's Proposed Action

    In this action, the EPA is proposing to approve SIP amendments,
shown in Table 8, to the Wyoming Air Quality Standards and Regulations,
Chapter 14, Emission Trading Program Regulations, Section 3, Sulfur
dioxide milestone inventory, revising the backstop trading program
SO2 emissions reporting requirements for Laramie River Units
1 and 2.

  Table 8--List of Wyoming Amendments That EPA Is Proposing To Approve
------------------------------------------------------------------------
    Amended sections in April 5, 2018 submittal proposed for approval
-------------------------------------------------------------------------
Chapter 14, Section 3: (d), (e).
------------------------------------------------------------------------

    We are also proposing to amend the Wyoming regional haze FIP
contained in 40 CFR 52.2636 to remove the 2014 FIP's NOX
emission limits and instead incorporate the BART alternative and
associated NOX and SO2 emission limits for
Laramie River Units 1-3, revise the NOX emission limit for
Unit 1, and add control technology requirements. Specifically, the EPA
is proposing to revise the NOX emission limits and add
SO2 emission limits and control technologies in Table 2 of
40 CFR 52.2636(c)(1) for Laramie River Units 1-3. We are also proposing
to add associated compliance dates in 40 CFR 52.2636(d)(4) for Laramie
River Units 1-3. Finally, we are proposing to reference SO2
in the following sections: Applicability (40 CFR 52.2636(a));
Definitions (40 CFR 52.2636(b)); Compliance determinations for NOX (40
CFR 52.2636(e)); Reporting (40 CFR 52.2636(h)); and Notifications (40
CFR 52.2636(i)). We are not proposing to change any other regulatory
text in 40 CFR 52.2636.

VIII. Incorporation by Reference

    In this document, EPA is proposing to include regulatory text in an
EPA final rule that includes incorporation by reference. In accordance
with requirements of 1 CFR 51.5, EPA is proposing to incorporate by
reference the SIP amendments described in Section VII of this preamble.
The EPA has made, and will continue to make, these materials generally
available through www.regulations.gov (refer to docket EPA-R08-OAR-
2018-0606) and at the EPA Region 8 Office (please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section of this
preamble for more information).

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is not a ``significant regulatory action'' under the
terms of Executive Order 12866 \56\ and was therefore not submitted to
the Office of Management and Budget (OMB) for review. This proposed
rule applies to only one facility in the State of Wyoming. It is
therefore not a rule of general applicability.
---------------------------------------------------------------------------

    \56\ 58 FR 51735, 51738 (October 4, 1993).
---------------------------------------------------------------------------

B. Executive Order 13771: Reducing Regulations and Controlling
Regulatory Costs

    This action is not an Executive Order 13771 regulatory action
because this action is not significant under Executive Order 12866.

C. Paperwork Reduction Act

    This proposed action does not impose an information collection
burden under the provisions of the Paperwork Reduction Act (PRA).\57\ A
``collection of information'' under the PRA means ``the obtaining,
causing to be obtained, soliciting, or requiring the disclosure to an
agency, third parties or the public of information by or for an agency
by means of identical questions posed to, or identical reporting,
recordkeeping, or disclosure requirements imposed on, ten or more
persons, whether such collection of information is mandatory,
voluntary, or required to obtain or retain a benefit.'' \58\ Because
this proposed rule revises the NOX and SO2
emission limits and associated reporting requirements for one facility,
the PRA does not apply.
---------------------------------------------------------------------------

    \57\ 44 U.S.C. 3501 et seq.
    \58\ 5 CFR 1320.3(c) (emphasis added).
---------------------------------------------------------------------------

D. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations and small governmental jurisdictions.
    For purposes of assessing the impacts of this proposed rule on
small entities, small entity is defined as: (1) A small business as
defined by the Small Business Administration's (SBA) regulations at 13
CFR 121.201; (2) a small governmental jurisdiction that is a government
of a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
    After considering the economic impacts of this proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities under the
RFA. This rule does not impose any requirements or create impacts on
small entities as no small entities are subject to the requirements of
this rule.

E. Unfunded Mandates Reform Act (UMRA)

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for federal agencies to assess the
effects of

their regulatory actions on state, local and tribal governments and the
private sector. Under section 202 of UMRA, the EPA generally must
prepare a written statement, including a cost-benefit analysis, for
final rules with ``Federal mandates'' that may result in expenditures
to state, local, and tribal governments, in the aggregate, or to the
private sector, of $100 million or more (adjusted for inflation) in any
one year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of UMRA generally requires the EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective, or least burdensome alternative
that achieves the objectives of the rule. The provisions of section 205
of UMRA do not apply when they are inconsistent with applicable law.
Moreover, section 205 of UMRA allows the EPA to adopt an alternative
other than the least costly, most cost-effective, or least burdensome
alternative if the Administrator publishes with the final rule an
explanation why that alternative was not adopted. Before the EPA
establishes any regulatory requirements that may significantly or
uniquely affect small governments, including tribal governments, it
must have developed under section 203 of UMRA a small government agency
plan. The plan must provide for notifying potentially affected small
governments, enabling officials of affected small governments to have
meaningful and timely input in the development of EPA regulatory
actions with significant federal intergovernmental mandates, and
informing, educating, and advising small governments on compliance with
the regulatory requirements.
    Under Title II of UMRA, the EPA has determined that this proposed
rule does not contain a federal mandate that may result in expenditures
that exceed the inflation-adjusted UMRA threshold of $100 million \59\
by state, local, or tribal governments or the private sector in any one
year. The proposed revisions to the 2014 FIP would reduce private
sector expenditures. Additionally, we do not foresee significant costs
(if any) for state and local governments. Thus, because the proposed
revisions to the 2014 FIP reduce annual expenditures, this proposed
rule is not subject to the requirements of sections 202 or 205 of UMRA.
This proposed rule is also not subject to the requirements of section
203 of UMRA because it contains no regulatory requirements that might
significantly or uniquely affect small governments.
---------------------------------------------------------------------------

    \59\ Adjusted to 2014 dollars, the UMRA threshold becomes $152
million.
---------------------------------------------------------------------------

F. Executive Order 13132: Federalism

    Executive Order 13132, Federalism,\60\ revokes and replaces
Executive Orders 12612 (Federalism) and 12875 (Enhancing the
Intergovernmental Partnership). Executive Order 13132 requires the EPA
to develop an accountable process to ensure ``meaningful and timely
input by State and local officials in the development of regulatory
policies that have federalism implications.'' \61\ ``Policies that have
federalism implications'' is defined in the Executive Order to include
regulations that have ``substantial direct effects on the States, on
the relationship between the national government and the States, or on
the distribution of power and responsibilities among the various levels
of government.'' \62\ Under Executive Order 13132, the EPA may not
issue a regulation ``that has federalism implications, that imposes
substantial direct compliance costs, . . . and that is not required by
statute, unless [the federal government provides the] funds necessary
to pay the direct [compliance] costs incurred by the State and local
governments,'' or the EPA consults with state and local officials early
in the process of developing the final regulation.\63\ The EPA also may
not issue a regulation that has federalism implications and that
preempts state law unless the agency consults with state and local
officials early in the process of developing the final regulation.
---------------------------------------------------------------------------

    \60\ 64 FR 43255, 43255-43257 (August 10, 1999).
    \61\ 64 FR 43255, 43257.
    \62\ Ibid.
    \63\ Ibid.
---------------------------------------------------------------------------

    This action does not have federalism implications. The proposed FIP
revisions will not have substantial direct effects on the states, on
the relationship between the national government and the states, or on
the distribution of power and responsibilities among the various levels
of government, as specified in Executive Order 13132. Thus, Executive
Order 13132 does not apply to this action.

G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments,'' requires the EPA to develop an
accountable process to ensure ``meaningful and timely input by tribal
officials in the development of regulatory policies that have tribal
implications.'' \64\ This proposed rule does not have tribal
implications, as specified in Executive Order 13175. It will not have
substantial direct effects on tribal governments. Thus, Executive Order
13175 does not apply to this rule. However, on September 5, 2018, the
EPA did send letters to each of the Wyoming tribes explaining our
regional haze proposed FIP revision and offering consultation.\65\
---------------------------------------------------------------------------

    \64\ 65 FR 67249, 67250 (November 9, 2000).
    \65\ Letters to tribal governments (September 5, 2018).
---------------------------------------------------------------------------

H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997). The EPA interprets Executive Order 13045 as applying
only to those regulatory actions that concern environmental health or
safety risks that the EPA has reason to believe may disproportionately
affect children, per the definition of ``covered regulatory action'' in
section 2-202 of the executive order. This action is not subject to
Executive Order 13045 because it does not concern an environmental
health risk or safety risk.

I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355
(May 22, 2001)), because it is not a significant regulatory action
under Executive Order 12866.

J. National Technology Transfer and Advancement Act

    Section 12 of the National Technology Transfer and Advancement Act
(NTTAA) of 1995 requires federal agencies to evaluate existing
technical standards when developing a new regulation. Section 12(d) of
NTTAA, Public Law 104-113, 12(d) (15 U.S.C. 272 note) directs the EPA
to consider and use ``voluntary consensus standards'' in its regulatory
activities unless to do so would be inconsistent with applicable law or
otherwise impractical. Voluntary consensus standards are technical
standards (e.g., materials specifications, test methods, sampling
procedures and business practices) that are developed or adopted by
voluntary consensus standards bodies. NTTAA directs the EPA to provide
Congress, through OMB, explanations when the agency decides not to use
available and applicable voluntary consensus standards.

    This action involves technical standards. The EPA has decided to
use the applicable monitoring requirements of 40 CFR part 75. Part 75
already incorporates a number of voluntary consensus standards.
Consistent with the agency's Performance Based Measurement System
(PBMS), part 75 sets forth performance criteria that allow the use of
alternative methods to the ones set forth in part 75. The PBMS approach
is intended to be more flexible and cost-effective for the regulated
community; it is also intended to encourage innovation in analytical
technology and improved data quality. At this time, the EPA is not
recommending any revisions to part 75. However, the EPA periodically
revises the test procedures set forth in part 75. When the EPA revises
the test procedures set forth in part 75 in the future, the EPA will
address the use of any new voluntary consensus standards that are
equivalent. Currently, even if a test procedure is not set forth in
part 75, the EPA is not precluding the use of any method, whether it
constitutes a voluntary consensus standard or not, as long as it meets
the performance criteria specified; however, any alternative methods
must be approved through the petition process under 40 CFR 75.66 before
they are used.

K. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898, establishes federal executive policy on
environmental justice.\66\ Its main provision directs federal agencies,
to the greatest extent practicable and permitted by law, to make
environmental justice part of their mission by identifying and
addressing, as appropriate, disproportionately high and adverse human
health or environmental effects of their programs, policies and
activities on minority populations and low-income populations in the
United States.
---------------------------------------------------------------------------

    \66\ 59 FR 7629 (February 16, 1994).
---------------------------------------------------------------------------

    I certify that the approaches under this proposed rule will not
have potential disproportionately high and adverse human health or
environmental effects on minority, low-income or indigenous/tribal
populations. As explained previously, the Wyoming Regional Haze FIP, as
revised by this action, will result in a significant reduction in
emissions compared to current levels. Although this revision will allow
an increase in future emissions as compared to the 2014 FIP, the
proposed FIP, as a whole, will still result in overall NOX
and SO2 reductions compared to those currently allowed. In
addition, the area where Laramie River Station is located has not been
designated nonattainment for any NAAQS. Thus, the proposed FIP will
ensure a significant reduction in NOX and SO2
emissions compared to current levels and will not create a
disproportionately high and adverse human health or environmental
effect on minority, low-income, or indigenous/tribal populations. The
EPA, however, will consider any input received during the public
comment period regarding environmental justice considerations.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Sulfur oxides.

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

    Dated: October 3, 2018.
Douglas Benevento,
Regional Administrator, Region 8.
    40 CFR part 52 is proposed to be amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart ZZ--Wyoming

0
2. Section 52.2620 is amended by revising:
0
a. In paragraph (c), the table entry for `Section 3' under the centered
table heading ``Chapter 14. Emission Trading Program Regulations.'';
and
0
b. In paragraph (e), the table entry for `(20)XX'.
    The revisions read as follows:

Sec.  52.2620   Identification of plan.

* * * * *
    (c) * * *

----------------------------------------------------------------------------------------------------------------
                                                State         EPA
       Rule No.             Rule title        effective    effective    Final rule/citation        Comments
                                                 date         date             date
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                Chapter 14. Emission Trading Program Regulations
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
Section 3............  Sulfur dioxide           2/5/2018   11/13/2018  [Federal Register
                        milestone inventory.                            citation], [Federal
                                                                        Register date of
                                                                        publication].

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *
    (e) * * *

----------------------------------------------------------------------------------------------------------------
                                                State         EPA
       Rule No.             Rule title        effective    effective    Final rule/citation        Comments
                                                 date         date             date
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
(20)XX...............  Addressing Regional      4/5/2018   11/13/2018  [Federal Register
                        Haze Visibility                                 citation], [Federal
                        Protection For The                              Register date of
                        Mandatory Federal                               publication].
                        Class I Areas
                        Required Under 40
                        CFR 51.309.

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

0
3. Section 52.2636 is amended by:
0
a. Revising paragraphs (a)(2), (b)(4), (b)(12), (c)(1), (c)(1) Table 2,
(d)(2) and (d)(3), (e), (e)(1)(i), (e)(1)(ii)(A) through (C), (h)(1),
and (i)(1); and
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b. Adding paragraphs (b)(13), (d)(4), and (e)(1)(ii)(D).
    The revisions and additions read as follows:

Sec.  52.2636   Implementation plan for regional haze.

    (a) * * *
    (2) This section also applies to each owner and operator of the
following emissions units in the State of Wyoming for which EPA
disapproved the State's BART determination and issued a SO2
and/or NOX BART Federal Implementation Plan:
    (i) Basin Electric Power Cooperative Laramie River Station Units 1,
2, and 3;
    (ii) PacifiCorp Dave Johnston Unit 3; and
    (iii) PacifiCorp Wyodak Power Plant Unit 1.
* * * * *
    (b) * * *
    (4) Continuous emission monitoring system or CEMS means the
equipment required by this section to sample, analyze, measure, and
provide, by means of readings recorded at least once every 15 minutes
(using an automated data acquisition and handling system (DAHS)), a
permanent record of SO2 and/or NOX emissions,
diluent, or stack gas volumetric flow rate.
* * * * *
    (12) SO2 means sulfur dioxide.
    (13) Unit means any of the units identified in paragraph (a) of
this section.
    (c) * * *
    (1) The owners/operators of emissions units subject to this section
shall not emit, or cause to be emitted, PM, NOX, or
SO2 in excess of the following limitations:
* * * * *

                                            Table 2 to Sec.   52.2636
[Emission limits and required control technologies for BART units for which the EPA disapproved the State's BART
                                      determination and implemented a FIP]
----------------------------------------------------------------------------------------------------------------
                                                                                SO2 emission
                                                                                NOX emission     limit-- lb/
                                                                                limit-- lb/        MMBtu
                                                       NOX required control        MMBtu (30-day     (averaged
              Source name/BART unit                         technology                rolling        annually
                                                                                average)       across both
                                                                                units)

----------------------------------------------------------------------------------------------------------------
Basin Electric Power Cooperative Laramie River    Selective Catalytic Reduction    \4\ 0.18/0.06            0.12
 Station/Unit 1 \1\.                               (SCR) \2\.
Basin Electric Power Cooperative Laramie River    Selective Non-catalytic              0.18/0.15
 Station/Unit 2 \1\.                               Reduction (SNCR) \3\.
Basin Electric Power Cooperative Laramie River    Selective Non-catalytic              0.18/0.15             N/A
 Station/Unit 3 \1\.                               Reduction (SNCR) \3\.
PacifiCorp Dave Johnston Unit 3.................  N/A...........................        \*\ 0.07             N/A
PacifiCorp Wyodak Power Plant/Unit 1............  N/A...........................            0.07             N/A
----------------------------------------------------------------------------------------------------------------
\1\ The owners and operators of Laramie River Station Unit 1 shall comply with the NOX emission limit of 0.18 lb/
  MMBtu on [the effective date of the final rule] and ending June 30, 2019. The owners and operators of Laramie
  River Station Unit 1 shall comply with the NOX emission limit of 0.06 lb/MMBtu on July 1, 2019. The owners and
  operators of the Laramie River Station Units 2 and 3 shall comply with the NOX emission limit of 0.18 lb/MMBtu
  on [the effective date of the final rule] and ending on December 30, 2018. The owners and operators of Laramie
  River Station Units 2 and 3 shall comply with the NOX emission limit of 0.15 lb/MMBtu on December 31, 2018.
  The owners and operators of Laramie River Station Units 1 and 2 shall comply with the SO2 emission limit of
  0.12 lb/MMBtu averaged annually across the two units on December 31, 2018.
\2\ By July 1, 2019.
\3\ By December 30, 2018.
\4\ These limits are in addition to the NOX emission limit for Laramie River Station Unit 1 of 0.07 MMBtu on a
  30-day rolling average.
* (or 0.28 and shut-down by December 31, 2027).

* * * * *
    (d) * * *
    (2) The owners and operators of Laramie River Station Unit 1 shall
comply with the NOX emission limit of 0.18 lb/MMBtu on [the
effective date of the final rule] and ending June 30, 2019. The owners
and operators of Laramie River Station Unit 1 shall comply with the
NOX emission limit of 0.06 lb/MMBtu on July 1, 2019. The
owners and operators of the Laramie River Station Units 2 and 3 shall
comply with the NOX emission limit of 0.18 lb/MMBtu on [the
effective date of the final rule] and ending on December 30, 2018. The
owners and operators of Laramie River Station Units 2 and 3 shall
comply with the NOX emission limit of 0.15 lb/MMBtu on
December 31, 2018. The owners and operators of Laramie River Station
Units 1 and 2 shall comply with the SO2 emission limit of
0.12 lb/MMBtu averaged annually across the two units on December 31,
2018.
    (3) The owners and operators of the other BART sources subject to
this section shall comply with the emissions limitations and other
requirements of this section by March 4, 2019.
    (4) Compliance alternatives for PacifiCorp Dave Johnston Unit 3.
(i) The owners and operators of PacifiCorp Dave Johnston Unit 3 will
meet a NOX emission limit of 0.07 lb/MMBtu (30-day rolling
average) by March 4, 2019; or
    (ii) Alternatively, the owners and operators of PacifiCorp Dave
Johnston Unit 3 will permanently cease operation of this unit on or
before December 31, 2027.
    (e) Compliance determinations for SO2 and NOX.
    (1) * * *
    (i) CEMS. At all times after the earliest compliance date specified
in paragraph (d) of this section, the owner/operator of each unit shall
maintain, calibrate, and operate a CEMS, in full compliance with the
requirements found at 40 CFR part 75, to accurately measure
SO2 and/or NOX, diluent, and stack gas volumetric
flow rate from each unit. The CEMS shall be used to determine
compliance with the emission limitations in paragraph (c) of this
section for each unit.
    (ii) * * *
    (A) For any hour in which fuel is combusted in a unit, the owner/
operator of each unit shall calculate the hourly average NOX
emission rates in lb/MMBtu at the CEMS in accordance with the
requirements of 40 CFR part 75. At the end of each operating day, the
owner/operator shall calculate and record a new 30-day rolling average

emission rate in lb/MMBtu from the arithmetic average of all valid
hourly emission rates from the CEMS for the current operating day and
the previous 29 successive operating days.
    (B) At the end of each calendar year, the owner/operator shall
calculate the annual average SO2 emission rate in lb/MMBtu
across Laramie River Station Units 1 and 2 as the sum of the
SO2 annual mass emissions (pounds) divided by the sum of the
annual heat inputs (MMBtu). For Laramie River Station Units 1 and 2,
the owner/operator shall calculate the annual mass emissions for
SO2 and the annual heat input in accordance with 40 CFR part
75 for each unit.
    (C) An hourly average SO2 and/or NOX emission
rate in lb/MMBtu is valid only if the minimum number of data points, as
specified in 40 CFR part 75, is acquired by both the pollutant
concentration monitor (SO2 and/or NOX) and the
diluent monitor (O2 or CO2).
    (D) Data reported to meet the requirements of this section shall
not include data substituted using the missing data substitution
procedures of subpart D of 40 CFR part 75, nor shall the data have been
bias adjusted according to the procedures of 40 CFR part 75.
* * * * *
    (h) * * *
    (1) The owner/operator of each unit shall submit quarterly excess
emissions reports for SO2 and/or NOX BART units
no later than the 30th day following the end of each calendar quarter.
Excess emissions means emissions that exceed the emissions limits
specified in paragraph (c) of this section. The reports shall include
the magnitude, date(s), and duration of each period of excess
emissions, specific identification of each period of excess emissions
that occurs during startups, shutdowns, and malfunctions of the unit,
the nature and cause of any malfunction (if known), and the corrective
action taken or preventative measures adopted.
* * * * *
    (i) * * *
    (1) The owner/operator shall promptly submit notification of
commencement of construction of any equipment which is being
constructed to comply with the SO2 and/or NOX
emission limits in paragraph (c) of this section.
* * * * *

[FR Doc. 2018-21949 Filed 10-10-18; 8:45 am]
 BILLING CODE 6560-50-P