Document ID: EPA-R08-OAR-2018-0606-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Wyoming; Revisions to Regional Haze State Implementation Plan; Revisions to Regional Haze Federal Implementation Plan
Posted Date: 2018-10-11T04:00Z

[Federal Register Volume 83, Number 197 (Thursday, October 11, 2018)]
[Proposed Rules]
[Pages 51403-51418]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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, (303) 312-6252, [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

[[Page 51404]]

    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\

[[Page 51405]]

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

[[Page 51406]]

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

[[Page 51407]]

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

[[Page 51408]]

 
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

[[Page 51409]]

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

[[Page 51410]]

    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

[[Page 51411]]

 
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

[[Page 51412]]

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

[[Page 51413]]

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

[[Page 51414]]

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

[[Page 51415]]

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.

[[Page 51416]]

    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.
 
                                                  * * * * * * *
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[[Page 51417]]

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
0
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]
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                                                                                                   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)
 
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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
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\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

[[Page 51418]]

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