```

[Federal Register Volume 78, Number 111 (Monday, June 10, 2013)]
[Proposed Rules]
[Pages 34737-34794]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-13611]

[[Page 34737]]

Vol. 78

Monday,

No. 111

June 10, 2013

Part III

Environmental Protection Agency

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40 CFR Part 52

Approval, Disapproval and Promulgation of Implementation Plans; State 
of Wyoming; Regional Haze State Implementation Plan; Federal 
Implementation Plan for Regional Haze; Proposed Rule

Federal Register / Vol. 78 , No. 111 / Monday, June 10, 2013 / 
Proposed Rules

[[Page 34738]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2012-0026, FRL-9820-4]

Approval, Disapproval and Promulgation of Implementation Plans; 
State of Wyoming; Regional Haze State Implementation Plan; Federal 
Implementation Plan for Regional Haze

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to partially approve and partially disapprove 
a State Implementation Plan (SIP) submitted by the State of Wyoming on 
January 12, 2011, that addresses regional haze. This SIP revision was 
submitted to address the requirements of the Clean Air Act (CAA or 
``the Act'') and our rules that require states to prevent any future 
and remedy any existing anthropogenic impairment of visibility in 
mandatory Class I areas caused by emissions of air pollutants from 
numerous sources located over a wide geographic area (also referred to 
as the ``regional haze program''). States are required to assure 
reasonable progress toward the national goal of achieving natural 
visibility conditions in Class I areas. EPA is taking this action 
pursuant to section 110 of the CAA.
    EPA is also proposing a Federal Implementation Plan (FIP) to 
address the deficiencies identified in our proposed partial disapproval 
of Wyoming's regional haze SIP. In lieu of our proposed FIP, or a 
portion thereof, we will propose approval of a SIP revision as 
expeditiously as practicable if the State submits such a revision and 
the revision matches the terms of our proposed FIP. We will also review 
and take action on any regional haze SIP submitted by the state to 
determine whether such SIP is approvable, regardless of whether or not 
its terms match those of the FIP. We encourage the State to submit a 
SIP revision to replace the FIP, either before or after our final 
action.

DATES: Comments: Written comments must be received at the address below 
on or before August 9, 2013. Public Hearing: A public hearing for this 
proposal is scheduled to be held on Monday, June 24, 2013, at the 
Hershchler Building, Room 1699, 122 W. 25th St., Cheyenne, Wyoming 
82002. The public hearing will be held from 1 p.m. until 5 p.m., and 
again from 6 p.m. until 8 p.m.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2012-0026, by one of the following methods:
    http://www.regulations.gov. Follow the on-line 
instructions for submitting comments.
     Email: r8airrulemakings@epa.gov.
     Fax: (303) 312-6064 (please alert the individual listed in 
the FOR FURTHER INFORMATION CONTACT if you are faxing comments).
     Mail: Carl Daly, Director, Air Program, Environmental 
Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, 
Denver, Colorado 80202-1129.
     Hand Delivery: Carl Daly, Director, Air Program, 
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 
Wynkoop, Denver, Colorado 80202-1129. Such deliveries are only accepted 
Monday through Friday, 8:00 a.m. to 4:30 p.m., excluding Federal 
holidays. Special arrangements should be made for deliveries of boxed 
information.
    Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-
2012-0026. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an email comment directly to EPA, without 
going through http://www.regulations.gov, your email address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional instructions on submitting 
comments, go to Section I. General Information of the SUPPLEMENTARY 
INFORMATION section of this document.
    Docket: All documents in the docket are listed in the http://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 http://www.regulations.gov or in hard copy at the Air Program, 
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 
Wynkoop, Denver, Colorado 80202-1129. 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: Laurel Dygowski, Air Program, U.S. 
Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595 
Wynkoop, Denver, Colorado 80202-1129, (303) 312-6144, 
dygowski.laurel@epa.gov.

SUPPLEMENTARY INFORMATION: 

Definitions

    For the purpose of this document, we are giving meaning to certain 
words or initials as follows:

    i. The words or initials Act or CAA mean or refer to the Clean 
Air Act, unless the context indicates otherwise.
    ii. The initials AFRC mean or refer to air-fuel ratio controls.
    iii. The initials BART mean or refer to Best Available Retrofit 
Technology.
    iv. The initials CAMx mean or refer to Comprehensive Air Quality 
Model.
    v. The initials CMAQ mean or refer to Community Multi-Scale Air 
Quality modeling system.
    vi. The initials CEMS mean or refer to continuous emission 
monitoring systems.
    vii. The initials EC mean or refer to elemental carbon.
    viii. The initials EGUs mean or refer to Electric Generating 
Units.
    ix. The initials EGR mean or refer to exhaust gas recirculation.
    x. The words EPA, we, us or our mean or refer to the United 
States Environmental Protection Agency.
    xi. The initials ESP mean or refer to electrostatic 
precipitator.
    xii. The initials FGC mean or refer to flue gas conditioning.
    xiii. The initials FGD mean or refer to flue gas 
desulfurization.
    xiv. The initials FGR mean or refer to external flue gas 
recirculation.

[[Page 34739]]

    xv. The initials FIP mean or refer to Federal Implementation 
Plan.
    xvi. The initials FLMs mean or refer to Federal Land Managers.
    xvii. The initials FS mean or refer to the U.S. Forest Service.
    xviii. The initials IMPROVE mean or refer to Interagency 
Monitoring of Protected Visual Environments monitoring network.
    xix. The initials IWAQM mean or refer to Interagency Workgroup 
on Air Quality Modeling.
    xx. The initials LEC mean or refer to low-emission combustion.
    xxi. The initials LNB mean or refer to low NOX 
burner.
    xxii. The initials LTS mean or refer to the long-term strategy.
    xxiii. The initials MW mean or refer to megawatts.
    xxiv. The initials NH3 mean or refer to ammonia.
    xxv. The initials NOX mean or refer to nitrogen oxides.
    xxvi. The initials NPS mean or refer to National Park Service.
    xxvii. The initials OC mean or refer to organic carbon.
    xxviii. The initials OFA mean or refer to overfire air.
    xxix. The initials PM2.5 mean or refer to particulate matter 
with an aerodynamic diameter of less than 2.5 micrometers.
    xxx. The initials PM10 mean or refer to particulate matter with 
an aerodynamic diameter of less than 10 micrometers.
    xxxi. The initials PSAT mean or refer to Particle Source 
Apportionment Technology.
    xxxii. The initials PSD mean or refer to Prevention of 
Signification Deterioration.
    xxxiii. The initials RAVI mean or refer to Reasonably 
Attributable Visibility Impairment.
    xxxiv. The initials RHR mean or refer to the Regional Haze Rule.
    xxxv. The initials RMC mean or refer to the Regional Modeling 
Center at the University of California Riverside.
    xxxvi. The initials RPGs mean or refer to Reasonable Progress 
Goals.
    xxxvii. The initials RPOs mean or refer to regional planning 
organizations.
    xxxviii. The initials SCR mean or refer to selective catalytic 
reduction.
    xxxix. The initials SIP mean or refer to State Implementation 
Plan.
    xl. The initials SNCR mean or refer to selective non-catalytic 
reduction.
    xli. The initials SO2 mean or refer to sulfur dioxide.
    xlii. The initials SOFA mean or refer to separated overfire air.
    xliii. The initials TSD mean or refer to Technical Support 
Document.
    xliv. The initials ULNB mean or refer to ultra-low 
NOX burners.
    xlv. The initials URP mean or refer to Uniform Rate of Progress.
    xlvi. The initials VOC mean or refer to volatile organic 
compounds.
    xlvii. The initials WAQSR mean or refer to Wyoming Air Quality 
Standards and Regulations.
    xlviii. The initials WEP mean or refer to Weighted Emissions 
Potential.
    xlix. The initials WRAP mean or refer to the Western Regional 
Air Partnership.
    l. The words Wyoming and State mean the State of Wyoming.

Table of Contents

I. General Information
    A. What should I consider as I prepare my comments for EPA?
II. EPA's Prior Action
III. Overview of Proposed Actions
IV. SIP and FIP Background
V. Background
    A. Regional Haze
    B. Requirements of the CAA and EPA's Regional Haze Rule (RHR)
    C. Roles of Agencies in Addressing Regional Haze
VI. Requirements for the Regional Haze SIPs
    A. The CAA and the Regional Haze Rule
    B. Determination of Baseline, Natural, and Current Visibility 
Conditions
    C. Determination of Reasonable Progress Goals
    D. Best Available Retrofit Technology
    E. Long-Term Strategy
    F. Coordinating Regional Haze and Reasonably Attributable 
Visibility Impairment
    G. Monitoring Strategy and Other Implementation Plan 
Requirements
    H. Consultation With States and Federal Land Managers (FLMs)
VII. EPA's Evaluation of Wyoming's Regional Haze SIP
    A. Affected Class I Areas
    B. Baseline Visibility, Natural Visibility, and Uniform Rate of 
Progress
    C. BART Determinations
    1. BART-Eligible Sources
    2. Sources Subject-to-BART
    a. Modeling Methodology
    b. Contribution Threshold
    c. Sources Identified by Wyoming as Subject-to-BART
    3. BART Determinations and Federally Enforceable Limits
    a. Costs of Compliance
    b. Visibility Improvement Modeling
    c. Summary of BART Determinations and Federally Enforceable 
Limits
    i. FMC Westvaco--Units NS-1A and NS-1B
    ii. General Chemical Green River--Boilers C and D
    iii. Basin Electric Laramie River Station--Units 1-3
    iv. PacifiCorp Dave Johnston--Units 3 and 4
    v. PacifiCorp Jim Bridger Units 1-4
    vi. PacifiCorp Naughton Units 1-3
    vii. PacifiCorp Wyodak--Unit 1
    D. Reasonable Progress Requirements
    1. Visibility Impairing Pollutants and Sources
    2. Four-Factor Analyses
    a. Stationary Sources
    b. Summary of Reasonable Progress Determinations and Limits
    i. Oil and Gas Area Sources
    ii. Mountain Cement Company Laramie Plant--Kiln
    3. Reasonable Progress Goals
    E. Long Term Strategy
    1. Emission Inventories
    2. Consultation and Emissions Reductions for Other States' Class 
I Areas
    3. Mandatory Long-Term Strategy Requirements
    a. Reductions Due to Ongoing Air Pollution Programs
    b. Measures To Mitigate the Impacts of Construction Activities
    c. Smoke Management
    d. Emission Limitations and Schedules for Compliance
    e. Source Retirement and Replacement Schedules
    f. Enforceability of Wyoming's Measures
    g. Anticipated Net Effect on Visibility Due to Projected Changes
    4. Our Conclusions on Wyoming's Long-Term Strategy
    F. Coordination of RAVI and Regional Haze Rule Requirements
    G. Monitoring Strategy and Other Implementation Plan 
Requirements
    H. Consultation With FLMs
    I. Periodic SIP Revisions and 5-Year Progress Reports
VIII. Federal Implementation Plan
    A. Disapproval of the State's NOX BART Determinations 
and Federal Implementation Plan for NOX BART 
Determinations and Limits
    1. Disapproval of the State's Basin Electric Laramie River Units 
1-3 NOX BART Determination and FIP To Address 
NOX BART
    2. Disapproval of the State's PacifiCorp Dave Johnston Unit 3 
and Unit 4 NOX BART Determination and FIP To Address 
NOX BART
    3. Proposals in the Alternative for PacifiCorp Jim Bridger Units 
1 and 2 NOX BART
    4. Disapproval of the State's PacifiCorp Naughton Units 1and 2 
NOX BART Determination and FIP to Address NOX 
BART
    5. Disapproval of the State's PacifiCorp Wyodak Unit 1 
NOX BART Determination and FIP to Address NOX 
BART
    B. Disapproval of the State's NOX Reasonable Progress 
Determinations and Federal Implementation Plan for NOX 
Reasonable Progress Determinations and Limits
    1. PacifiCorp Dave Johnston--Units 1 and 2
    C. Reasonable Progress Goals
    D. Federal Monitoring, Recordkeeping, and Reporting Requirements
    E. Federal Implementation Plan for the Long-Term Strategy
    F. Federal Implementation Plan for Coordination of RAVI and 
Regional Haze Long-Term Strategy
IX. EPA's Proposed Action
X. Statutory and Executive Order Reviews

I. General Information

A. What should I consider as I prepare my comments for EPA?

    1. Submitting CBI. Do not submit CBI to EPA through http://www.regulations.gov or email. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as 
CBI and then

[[Page 34740]]

identify electronically within the disk or CD ROM the specific 
information that is claimed as CBI. In addition to one complete version 
of the comment that includes information claimed as CBI, a copy of the 
comment that does not contain the information claimed as CBI must be 
submitted for inclusion in the public docket. Information so marked 
will not be disclosed except in accordance with procedures set forth in 
40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
    a. Identify the rulemaking by docket number and other identifying 
information (subject heading, Federal Register date and page number).
    b. Follow directions--The agency may ask you to respond to specific 
questions or organize comments by referencing a Code of Federal 
Regulations (CFR) part or section number.
    c. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    d. Describe any assumptions and provide any technical information 
and/or data that you used.
    e. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    f. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    g. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.
    h. Make sure to submit your comments by the comment period deadline 
identified.

II. EPA's Prior Action

    We signed a notice of proposed rulemaking on May 15, 2012, and it 
was published in the Federal Register on June 4, 2012 (77 FR 33022).
    In our proposal, we proposed to disapprove the following:
     The State's nitrogen oxides (NOX) best 
available retrofit technology (BART) determinations for PacifiCorp Dave 
Johnston Unit 3, PacifiCorp Jim Bridger Units 1 and 2, PacifiCorp 
Wyodak Unit 1, and Basin Electric Laramie River Station Units 1, 2, and 
3.
     The State's NOX reasonable progress 
determination for PacifiCorp Dave Johnston Units 1 and 2.
     The State's Reasonable Progress Goals (RPGs).
     The State's monitoring, recordkeeping, and reporting 
requirements in Chapter 6.4 of the SIP.
     Portions of the State's long-term strategy (LTS) that rely 
on or reflect aspects of the regional haze SIP that we are 
disapproving.
     The State's SIP because it does not contain the necessary 
provisions to meet the requirements for the coordination of the review 
of the reasonably attributable visibility impairment (RAVI) and the 
regional haze LTS.
    We proposed to approve the remaining aspects of the State's January 
12, 2011 SIP submittal. We also sought comment on two alternative 
proposals related to the State's NOX BART determination for 
PacifiCorp Jim Bridger Units 1 and 2.
    We proposed the promulgation of a FIP to address the deficiencies 
in the Wyoming regional haze SIP that we identified in the proposal. 
The proposed FIP included the following elements:
     NOX BART determinations and limits for 
PacifiCorp Dave Johnston Unit 3, PacifiCorp Jim Bridger Units 1 and 2, 
PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River Station 
Units 1, 2, and 3.
     NOX reasonable progress determination and 
limits for PacifiCorp Dave Johnston Units 1 and 2.
     RPGs consistent with the SIP limits proposed for approval 
and the proposed FIP limits.
     Monitoring, recordkeeping, and reporting requirements 
applicable to all BART and reasonable progress sources for which there 
is a SIP or FIP emissions limit.
     LTS elements pertaining to emission limits and compliance 
schedules for the proposed BART and reasonable progress FIP emission 
limits.
     Provisions to ensure the coordination of the RAVI and 
regional haze LTS.
    In lieu of our proposed FIP, or a portion thereof, we stated that 
we would propose approval of a SIP revision if the State submits such a 
revision and the revision matches the terms of our proposed FIP. We 
encouraged the State to submit a SIP revision to replace the FIP, 
either before or after our final action.
    We requested comments on all aspects of our proposed action and 
provided a 60-day comment period, with the comment period closing on 
August 3, 2012. We also held two public hearings. The public hearings 
were held on June 26, 2012, in Cheyenne, Wyoming and June 28, 2012, in 
Rock Springs, Wyoming.
    The Conservation Organizations \1\ and the National Park Service 
submitted comments during the public comment period pertaining to, 
among other things, the cost analyses that the State relied upon in its 
SIP and that EPA subsequently relied on to make its proposed rulemaking 
decision. The commenters asserted that the State overestimated the 
costs for some control technologies and underestimated the costs for 
other control technologies. Based on our review of these comments and 
upon further review of the State's cost and visibility analyses, we 
determined that the State's analyses are flawed in several respects and 
are therefore inconsistent with the BART Guidelines and statutory 
requirements, as discussed further in this notice. As a result, EPA 
conducted its own cost analyses for the BART and reasonable progress 
electric generating units (EGUs), and also revised its modeling of the 
visibility improvement for these sources in order to be comparable to 
the revised costs analyses as explained in section V.II.C.3. The 
revised costs and visibility modeling are explained in further detail 
in section VII.C.3. Because we have developed new cost and visibility 
improvement modeling analyses, we are re-proposing action on Wyoming's 
SIP in order to give the public the opportunity to comment on our 
updated cost and visibility analyses and our proposed determinations 
based on this new information.
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    \1\ The Conservation Organizations refers to comments submitted 
on behalf of Powder River Basin Resource Council, Wyoming Outdoor 
Council, Greater Yellowstone Coalition, Sierra Club, National Parks 
Conservation Association, and WildEarth Guardians.
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III. Overview of Proposed Actions

    EPA is proposing to partially approve and partially disapprove a 
regional haze SIP submitted by the State of Wyoming on January 12, 
2011. Specifically, we are proposing to disapprove the following:
     The State's NOX BART determinations for 
PacifiCorp Dave Johnston Units 3 and 4, PacifiCorp Naughton Units 1 and 
2, PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River Units 1, 
2, and 3.
     The State's NOX reasonable progress 
determinations for PacifiCorp Dave Johnston Units 1 and 2.
     Wyoming's RPGs.
     The State's monitoring, recordkeeping, and reporting 
requirements in Chapter 6.4 of the SIP.
     Portions of the State's LTS that rely on or reflect other 
aspects of the regional haze SIP.
     The provisions necessary to meet the requirements for the 
coordination of the review of the RAVI and the regional haze LTS.
    We are proposing to approve the remaining aspects of the State's 
January 12, 2011SIP submittal. However, we are also seeking comment on 
an alternative proposal, related to the State's NOX BART 
determinations, for PacifiCorp Jim Bridger Units 1 and 2, that would

[[Page 34741]]

involve disapproval and the promulgation of a FIP.
    We are proposing the promulgation of a FIP to address the 
deficiencies in the Wyoming regional haze SIP that we have identified 
in this notice. The proposed FIP includes the following elements:
     NOX BART determinations and limits for 
PacifiCorp Dave Johnston Units 3 and 4, PacifiCorp Naughton Units 1 and 
2, PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River Units 1, 
2, and 3.
     NOX reasonable progress determinations and 
limits for PacifiCorp Dave Johnston Units 1 and 2.
     RPGs consistent with the SIP limits proposed for approval 
and the proposed FIP limits.
     Monitoring, recordkeeping, and reporting requirements 
applicable to all BART and reasonable progress sources for which there 
is a SIP or FIP emissions limit.
     LTS elements pertaining to emission limits and compliance 
schedules for the proposed BART and reasonable progress FIP emission 
limits.
     Provisions to ensure the coordination of the RAVI and 
regional haze LTS.
    In lieu of our proposed FIP, or a portion thereof, we will propose 
approval of a SIP revision as expeditiously as practicable if the State 
submits such a revision and the revision matches the terms of our 
proposed FIP. We will also review and take action on any regional haze 
SIP submitted by the state to determine whether such SIP is approvable, 
regardless of whether or not its terms match those of the FIP. We 
encourage the State to submit a SIP revision to replace the FIP, either 
before or after our final action.

IV. SIP and FIP Background

    The CAA requires each state to develop plans to meet various air 
quality requirements, including protection of visibility. CAA sections 
110(a), 169A, and 169B. The plans developed by a state are referred to 
as SIPs. A state must submit its SIPs and SIP revisions to us for 
approval. Once approved, a SIP is enforceable by EPA and citizens under 
the CAA, also known as being federally enforceable. If a state fails to 
make a required SIP submittal or if we find that a state's required 
submittal is incomplete or unapprovable, then we must promulgate a FIP 
to fill this regulatory gap. CAA section 110(c)(1). As discussed 
elsewhere in this notice, we are proposing to disapprove aspects of 
Wyoming's regional haze SIP. We are proposing a FIP to address the 
deficiencies in Wyoming's regional haze SIP.

V. Background

A. Regional Haze

    Regional haze is visibility impairment that is produced by a 
multitude of sources and activities which are located across a broad 
geographic area and emit fine particles (PM2.5) (e.g., 
sulfates, nitrates, organic carbon (OC), elemental carbon (EC), and 
soil dust), and their precursors (e.g., sulfur dioxide 
(SO2), NOX, and in some cases, ammonia 
(NH3) and volatile organic compounds (VOC)). Fine particle 
precursors react in the atmosphere to form PM2.5, which 
impairs visibility by scattering and absorbing light. Visibility 
impairment reduces the clarity, color, and visible distance that one 
can see. PM2.5 can also cause serious health effects and 
mortality in humans and contributes to environmental effects such as 
acid deposition and eutrophication.
    Data from the existing visibility monitoring network, the 
``Interagency Monitoring of Protected Visual Environments'' (IMPROVE) 
monitoring network, show that visibility impairment caused by air 
pollution occurs virtually all the time at most national park and 
wilderness areas. The average visual range \2\ in many Class I areas 
(i.e., national parks and memorial parks, wilderness areas, and 
international parks meeting certain size criteria) in the western 
United States is 100-150 kilometers, or about one-half to two-thirds of 
the visual range that would exist without anthropogenic air pollution. 
In most of the eastern Class I areas of the United States, the average 
visual range is less than 30 kilometers, or about one-fifth of the 
visual range that would exist under estimated natural conditions. 64 FR 
35715 (July 1, 1999).
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    \2\ Visual range is the greatest distance, in kilometers or 
miles, at which a dark object can be viewed against the sky.
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B. Requirements of the CAA and EPA's Regional Haze Rule (RHR)

    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 \3\ which 
impairment results from manmade air pollution.'' On December 2, 1980, 
EPA 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.'' 45 FR 80084. These regulations represented the first 
phase in addressing visibility impairment. EPA deferred action on 
regional haze that emanates from a variety of sources until monitoring, 
modeling and scientific knowledge about the relationships between 
pollutants and visibility impairment were improved.
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    \3\ 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 which they consider to have visibility as an 
important value, the requirements of the visibility program set 
forth in section 169A of the CAA apply only to ``mandatory Class I 
Federal areas.'' Each mandatory Class I Federal area is the 
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i). 
When we use the term ``Class I area'' in this action, we mean a 
``mandatory Class I Federal area.''
---------------------------------------------------------------------------

    Congress added section 169B to the CAA in 1990 to address regional 
haze issues. EPA promulgated a rule to address regional haze on July 1, 
1999. 64 FR 35714 (July 1, 1999), codified at 40 CFR part 51, subpart 
P. The RHR revised the existing visibility regulations to integrate 
into the regulation provisions addressing regional haze impairment and 
established a comprehensive visibility protection program for Class I 
areas. The requirements for regional haze, found at 40 CFR 51.308 and 
51.309, are included in EPA's visibility protection regulations at 40 
CFR 51.300-309. Some of the main elements of the regional haze 
requirements are summarized in section III of this preamble. The 
requirement to submit a regional haze SIP applies to all 50 states, the 
District of Columbia and the Virgin Islands. 40 CFR 51.308(b) requires 
states to submit the first implementation plan addressing regional haze 
visibility impairment no later than December 17, 2007.\4\
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    \4\ EPA's regional haze regulations require subsequent updates 
to the regional haze SIPs. 40 CFR 51.308(g)-(i).
---------------------------------------------------------------------------

    Few states submitted a regional haze SIP prior to the December 17, 
2007 deadline, and on January 15, 2009, EPA found that 37 states 
(including Wyoming), the District of Columbia, and the Virgin Islands, 
had failed to submit SIPs addressing the regional haze requirements. 74 
FR 2392. Once EPA

[[Page 34742]]

has found that a state has failed to make a required submission, EPA is 
required to promulgate a FIP within two years unless the state submits 
a SIP and the Agency approves it within the two-year period. CAA Sec.  
110(c)(1).

C. Roles of Agencies in Addressing Regional Haze

    Successful implementation of the regional haze program will require 
long-term regional coordination among states, tribal governments, and 
various federal agencies. As noted above, pollution affecting the air 
quality in Class I areas can be transported over long distances, even 
hundreds of kilometers. Therefore, to effectively address the problem 
of visibility impairment in Class I areas, states need to develop 
strategies in coordination with one another, taking into account the 
effect of emissions from one jurisdiction on the air quality in 
another.
    Because the pollutants that lead to regional haze can originate 
from sources located across broad geographic areas, EPA has encouraged 
the states and tribes across the United States to address visibility 
impairment from a regional perspective. Five regional planning 
organizations (RPOs) were developed to address regional haze and 
related issues. The RPOs first evaluated technical information to 
better understand how their states and tribes impact Class I areas 
across the country, and then pursued the development of regional 
strategies to reduce emissions of pollutants that lead to regional 
haze.
    The Western Regional Air Partnership (WRAP) RPO is a collaborative 
effort of state governments, tribal governments, and various federal 
agencies established to initiate and coordinate activities associated 
with the management of regional haze, visibility and other air quality 
issues in the western United States. WRAP member state governments 
include: Alaska, Arizona, California, Colorado, Idaho, Montana, New 
Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and 
Wyoming. Tribal members include Campo Band of Kumeyaay Indians, 
Confederated Salish and Kootenai Tribes, Cortina Indian Rancheria, Hopi 
Tribe, Hualapai Nation of the Grand Canyon, Native Village of Shungnak, 
Nez Perce Tribe, Northern Cheyenne Tribe, Pueblo of Acoma, Pueblo of 
San Felipe, and Shoshone-Bannock Tribes of Fort Hall.

VI. Requirements for Regional Haze SIPs

    The following is a summary of the requirements of the RHR. See 40 
CFR 51.308 for further detail regarding the requirements of the rule.

A. The CAA and the Regional Haze Rule

    Regional haze SIPs must assure reasonable progress towards the 
national goal of achieving natural visibility conditions in Class I 
areas. Section 169A of the CAA and EPA's implementing regulations 
require states to establish long-term strategies for making reasonable 
progress toward meeting this goal. Implementation plans must also give 
specific attention to certain stationary sources that were in existence 
on August 7, 1977, but were not in operation before August 7, 1962, and 
require these sources, where appropriate, to install BART controls for 
the purpose of eliminating or reducing visibility impairment. The 
specific regional haze SIP requirements are discussed in further detail 
below.

B. Determination of Baseline, Natural, and Current Visibility 
Conditions

    The RHR establishes the deciview as the principal metric or unit 
for expressing visibility. See 70 FR 39104, 39118. This visibility 
metric expresses uniform changes in the degree of haze in terms of 
common increments across the entire range of visibility conditions, 
from pristine to extremely hazy conditions. Visibility expressed in 
deciviews is determined by using air quality measurements to estimate 
light extinction and then transforming the value of light extinction 
using a logarithmic function. The deciview is a more useful measure for 
tracking progress in improving visibility than light extinction itself 
because each deciview change is an equal incremental change in 
visibility perceived by the human eye. Most people can detect a change 
in visibility at one deciview.\5\
---------------------------------------------------------------------------

    \5\ The preamble to the RHR provides additional details about 
the dv. 64 FR 35714, 35725 (July 1, 1999).
---------------------------------------------------------------------------

    The deciview is used in expressing RPGs (which are interim 
visibility goals towards meeting the national visibility goal), 
defining baseline, current, and natural conditions, and tracking 
changes in visibility. The regional haze SIPs must contain measures 
that ensure ``reasonable progress'' toward the national goal of 
preventing and remedying visibility impairment in Class I areas caused 
by anthropogenic air pollution by reducing anthropogenic emissions that 
cause regional haze. The national goal is a return to natural 
conditions, i.e., anthropogenic sources of air pollution would no 
longer impair visibility in Class I areas.
    To track changes in visibility over time at each of the 156 Class I 
areas covered by the visibility program (40 CFR 81.401-437), and as 
part of the process for determining reasonable progress, states must 
calculate the degree of existing visibility impairment at each Class I 
area at the time of each regional haze SIP submittal and periodically 
review progress every five years midway through each 10-year 
implementation period. To do this, the RHR requires states to determine 
the degree of impairment (in deciviews) for the average of the 20 
percent least impaired (``best'') and 20 percent most impaired 
(``worst'') visibility days over a specified time period at each of 
their Class I areas. In addition, states must also develop an estimate 
of natural visibility conditions for the purpose of comparing progress 
toward the national goal. Natural visibility is determined by 
estimating the natural concentrations of pollutants that cause 
visibility impairment and then calculating total light extinction based 
on those estimates. We have provided guidance to states regarding how 
to calculate baseline, natural and current visibility conditions.\6\
---------------------------------------------------------------------------

    \6\ Guidance for Estimating Natural Visibility Conditions Under 
the Regional Haze Rule, September 2003, EPA-454/B-03-005, available 
at http://www.epa.gov/ttncaaa1/t1/memoranda/Regional Haze_
envcurhr_gd.pdf, (hereinafter referred to as ``our 2003 Natural 
Visibility Guidance''); and Guidance for Tracking Progress Under the 
Regional Haze Rule, (September 2003, EPA-454/B-03-004, available at 
http://www.epa.gov/ttncaaa1/t1/memoranda/rh_tpurhr_gd.pdf, 
(hereinafter referred to as our ``2003 Tracking Progress 
Guidance'').
---------------------------------------------------------------------------

    For the first regional haze SIPs that were due by December 17, 
2007, ``baseline visibility conditions'' were the starting points for 
assessing ``current'' visibility impairment. Baseline visibility 
conditions represent the degree of visibility impairment for the 20 
percent least impaired days and 20 percent most impaired days for each 
calendar year from 2000 to 2004. Using monitoring data for 2000 through 
2004, states are required to calculate the average degree of visibility 
impairment for each Class I area, based on the average of annual values 
over the five-year period. The comparison of initial baseline 
visibility conditions to natural visibility conditions indicates the 
amount of improvement necessary to attain natural visibility, while the 
future comparison of baseline conditions to the then current conditions 
will indicate the amount of progress made. In general, the 2000-2004 
baseline period is considered the time from which improvement in 
visibility is measured.

[[Page 34743]]

C. Determination of Reasonable Progress Goals

    The vehicle for ensuring continuing progress towards achieving the 
natural visibility goal is the submission of a series of regional haze 
SIPs from the states that establish two RPGs (i.e., two distinct goals, 
one for the ``best'' and one for the ``worst'' days) for every Class I 
area for each (approximately) 10-year implementation period. See 40 CFR 
51.308(d), (f). The RHR does not mandate specific milestones or rates 
of progress, but instead calls for states to establish goals that 
provide for ``reasonable progress'' toward achieving natural visibility 
conditions. In setting RPGs, states must provide for an improvement in 
visibility for the most impaired days over the (approximately) 10-year 
period of the SIP, and ensure no degradation in visibility for the 
least impaired days over the same period. Id.
    In establishing RPGs, states are required to consider the following 
factors established in section 169A of the CAA and in our RHR at 40 CFR 
51.308(d)(1)(i)(A): (1) The costs of compliance; (2) the time necessary 
for compliance; (3) the energy and non-air quality environmental 
impacts of compliance; and (4) the remaining useful life of any 
potentially affected sources. States must demonstrate in their SIPs how 
these factors are considered when selecting the RPGs for the best and 
worst days for each applicable Class I area. In setting the RPGs, 
states must also consider the rate of progress needed to reach natural 
visibility conditions by 2064 (referred to as the ``uniform rate of 
progress'' (URP) or the ``glidepath'') and the emission reduction 
measures needed to achieve that rate of progress over the 10-year 
period of the SIP. Uniform progress towards achievement of natural 
conditions by the year 2064 represents a rate of progress, which states 
are to use for analytical comparison to the amount of progress they 
expect to achieve. In setting RPGs, each state with one or more Class I 
areas (``Class I state'') must also consult with potentially 
``contributing states,'' i.e., other nearby states with emission 
sources that may be affecting visibility impairment at the state's 
Class I areas. 40 CFR 51.308(d)(1)(iv). In determining whether a 
state's goals for visibility improvement provide for reasonable 
progress toward natural visibility conditions, EPA is required to 
evaluate the demonstrations developed by the state pursuant to 
paragraphs 40 CFR 51.308(d)(1)(i) and (d)(1)(ii). 40 CFR 
51.308(d)(1)(iii).

D. Best Available Retrofit Technology

    Section 169A of the CAA directs states 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 
to revise their SIPs to contain such measures as may be necessary to 
make reasonable progress towards the natural visibility goal, including 
a requirement that certain categories of existing major stationary 
sources \7\ built between 1962 and 1977 procure, install, and operate 
the ``Best Available Retrofit Technology'' as determined by the state. 
Under the RHR, states are directed to conduct BART determinations for 
such ``BART-eligible'' sources that may be anticipated to cause or 
contribute to any visibility impairment in a Class I area. 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.
---------------------------------------------------------------------------

    \7\ The set of ``major stationary sources'' potentially subject-
to-BART is listed in CAA section 169A(g)(7).
---------------------------------------------------------------------------

    On July 6, 2005, EPA published the Guidelines for BART 
Determinations Under the Regional Haze Rule at appendix Y to 40 CFR 
part 51 (hereinafter referred to as the ``BART Guidelines'') to assist 
states in determining which of their sources should be subject to the 
BART requirements and in determining appropriate emission limits for 
each applicable source. 70 FR 39104. In making a BART determination for 
a fossil fuel-fired electric generating plant with a total generating 
capacity in excess of 750 megawatts (MW), a state must use the approach 
set forth in the BART Guidelines. A state is encouraged, but not 
required, to follow the BART Guidelines in making BART determinations 
for other types of sources. Regardless of source size or type, a state 
must meet the requirements of the CAA and our regulations for selection 
of BART, and the state's BART analysis and determination must be 
reasonable in light of the overarching purpose of the regional haze 
program.
    The process of establishing BART emission limitations can be 
logically broken down into three steps: First, states identify those 
sources which meet the definition of ``BART-eligible source'' set forth 
in 40 CFR 51.301;\8\ second, states determine which of such sources 
``emits any air pollutant which may reasonably be anticipated to cause 
or contribute to any impairment of visibility in any such area'' (a 
source which fits this description is ``subject to BART''); and third, 
for each source subject-to-BART, states then identify the best 
available type and level of control for reducing emissions.
---------------------------------------------------------------------------

    \8\ BART-eligible sources are those sources that have the 
potential to emit 250 tons or more of a visibility-impairing air 
pollutant, were not in operation prior to August 7, 1962, but were 
in existence on August 7, 1977, and whose operations fall within one 
or more of 26 specifically listed source categories. 40 CFR 51.301.
---------------------------------------------------------------------------

    States must address all visibility-impairing pollutants emitted by 
a source in the BART determination process. The most significant 
visibility impairing pollutants are SO2, NOX, and 
PM. EPA has stated that states should use their best judgment in 
determining whether VOC or NH3 emissions impair visibility 
in Class I areas.
    Under the BART Guidelines, states may select an exemption threshold 
value for their BART modeling, below which a BART-eligible source would 
not be expected to cause or contribute to visibility impairment in any 
Class I area. The state must document this exemption threshold value in 
the SIP and must state the basis for its selection of that value. Any 
source with emissions that model above the threshold value would be 
subject to a BART determination review. The BART Guidelines acknowledge 
varying circumstances affecting different Class I areas. States should 
consider the number of emission sources affecting the Class I areas at 
issue and the magnitude of the individual sources' impacts. Any 
exemption threshold set by the state should not be higher than 0.5 
deciview. 40 CFR part 51, appendix Y, section III.A.1.
    In their SIPs, states must identify the sources that are subject-
to-BART and document their BART control determination analyses for such 
sources. In making their BART determinations, section 169A(g)(2) of the 
CAA requires that states consider the following factors when evaluating 
potential control technologies: (1) The costs of compliance; (2) the 
energy and non-air quality environmental impacts of compliance; (3) any 
existing pollution control technology in use at the source; (4) the 
remaining useful life of the source; and (5) the degree of improvement 
in visibility which may reasonably be anticipated to result from the 
use of such technology.
    A regional haze SIP must include source-specific BART emission 
limits and compliance schedules for each source subject-to-BART. Once a 
state

[[Page 34744]]

has made its BART determination, the BART controls must be installed 
and in operation as expeditiously as practicable, but no later than 
five years after the date of EPA approval of the regional haze SIP. CAA 
section 169(g)(4) and 40 CFR 51.308(e)(1)(iv). In addition to what is 
required by the RHR, general SIP requirements mandate that the SIP must 
also include all regulatory requirements related to monitoring, 
recordkeeping, and reporting for the BART controls on the source. See 
CAA section 110(a). As noted above, the RHR allows states to implement 
an alternative program in lieu of BART so long as the alternative 
program can be demonstrated to achieve greater reasonable progress 
toward the national visibility goal than would BART.

E. Long-Term Strategy

    Consistent with the requirement in section 169A(b) of the CAA that 
states include in their regional haze SIP a 10- to 15-year strategy for 
making reasonable progress, section 51.308(d)(3) of the RHR requires 
that states include a LTS in their regional haze SIPs. The LTS is the 
compilation of all control measures a state will use during the 
implementation period of the specific SIP submittal to meet applicable 
RPGs. The LTS must include ``enforceable emissions limitations, 
compliance schedules, and other measures as necessary to achieve the 
reasonable progress goals'' for all Class I areas within, or affected 
by emissions from, the state. 40 CFR 51.308(d)(3).
    When a state's emissions are reasonably anticipated to cause or 
contribute to visibility impairment in a Class I area located in 
another state, the RHR requires the impacted state to coordinate with 
the contributing states in order to develop coordinated emissions 
management strategies. 40 CFR 51.308(d)(3)(i). In such cases, the 
contributing state must demonstrate that it has included, in its SIP, 
all measures necessary to obtain its share of the emission reductions 
needed to meet the RPGs for the Class I area. Id. at (d)(3)(ii). The 
RPOs have provided forums for significant interstate consultation, but 
additional consultations between states may be required to sufficiently 
address interstate visibility issues. This is especially true where two 
states belong to different RPOs.
    States should consider all types of anthropogenic sources of 
visibility impairment in developing their long-term strategy, including 
stationary, minor, mobile, and area sources. At a minimum, states must 
describe how each of the following seven factors listed below are taken 
into account in developing their LTS: (1) Emission reductions due to 
ongoing air pollution control programs, including measures to address 
RAVI; (2) measures to mitigate the impacts of construction activities; 
(3) emissions limitations and schedules for compliance to achieve the 
RPG; (4) source retirement and replacement schedules; (5) smoke 
management techniques for agricultural and forestry management purposes 
including plans as currently exist within the state for these purposes; 
(6) enforceability of emissions limitations and control measures; and 
(7) the anticipated net effect on visibility due to projected changes 
in point, area, and mobile source emissions over the period addressed 
by the LTS. 40 CFR 51.308(d)(3)(v).

F. Coordinating Regional Haze and Reasonably Attributable Visibility 
Impairment

    As part of the RHR, EPA revised 40 CFR 51.306(c) regarding the LTS 
for RAVI to require that the RAVI plan must provide for a periodic 
review and SIP revision not less frequently than every three years 
until the date of submission of the state's first plan addressing 
regional haze visibility impairment, which was due December 17, 2007, 
in accordance with 40 CFR 51.308(b) and (c). On or before this date, 
the state must revise its plan to provide for review and revision of a 
coordinated LTS for addressing RAVI and regional haze, and the state 
must submit the first such coordinated LTS with its first regional haze 
SIP. Future coordinated LTS's, and periodic progress reports evaluating 
progress towards RPGs, must be submitted consistent with the schedule 
for SIP submission and periodic progress reports set forth in 40 CFR 
51.308(f) and 51.308(g), respectively. The periodic review of a state's 
LTS must report on both regional haze and RAVI impairment and must be 
submitted to EPA as a SIP revision.

F. Monitoring Strategy and Other Implementation Plan Requirements

    Section 51.308(d)(4) of the RHR includes the requirement for a 
monitoring strategy for measuring, characterizing, and reporting of 
regional haze visibility impairment that is representative of all 
mandatory Class I Federal areas within the state. The strategy must be 
coordinated with the monitoring strategy required in section 51.305 for 
RAVI. Compliance with this requirement may be met through 
``participation'' in the IMPROVE network, i.e., review and use of 
monitoring data from the network. The monitoring strategy is due with 
the first regional haze SIP, and it must be reviewed every five years. 
The monitoring strategy must also provide for additional monitoring 
sites if the IMPROVE network is not sufficient to determine whether 
RPGs will be met.
    The SIP must also provide for the following:
     Procedures for using monitoring data and other information 
in a state with mandatory Class I areas to determine the contribution 
of emissions from within the state to regional haze visibility 
impairment at Class I areas both within and outside the state;
     Procedures for using monitoring data and other information 
in a state with no mandatory Class I areas to determine the 
contribution of emissions from within the state to regional haze 
visibility impairment at Class I areas in other states;
     Reporting of all visibility monitoring data to the 
Administrator at least annually for each Class I area in the state, and 
where possible, in electronic format;
     Developing a statewide inventory of emissions of 
pollutants that are reasonably anticipated to cause or contribute to 
visibility impairment in any Class I area. The inventory must include 
emissions for a baseline year, emissions for the most recent year for 
which data are available, and estimates of future projected emissions. 
A state must also make a commitment to update the inventory 
periodically; and
     Other elements, including reporting, recordkeeping, and 
other measures necessary to assess and report on visibility.
    The RHR requires control strategies to cover an initial 
implementation period extending to the year 2018, with a comprehensive 
reassessment and revision of those strategies, as appropriate, every 10 
years thereafter. Periodic SIP revisions must meet the core 
requirements of section 51.308(d) with the exception of BART. The 
requirement to evaluate sources for BART applies only to the first 
regional haze SIP. Facilities subject-to-BART must continue to comply 
with the BART provisions of section 51.308(e), as noted above. Periodic 
SIP revisions will assure that the statutory requirement of reasonable 
progress will continue to be met.

G. Consultation With States and Federal Land Managers (FLMs)

    The RHR requires that states consult with FLMs before adopting and 
submitting their SIPs. 40 CFR 51.308(i). States must provide FLMs an 
opportunity for consultation, in person and at least 60 days prior to 
holding any

[[Page 34745]]

public hearing on the SIP. This consultation must include the 
opportunity for the FLMs to discuss their assessment of impairment of 
visibility in any Class I area and to offer recommendations on the 
development of the RPGs and on the development and implementation of 
strategies to address visibility impairment. Further, a state must 
include in its SIP a description of how it addressed any comments 
provided by the FLMs. Finally, a SIP must provide procedures for 
continuing consultation between the state and FLMs regarding the 
state's visibility protection program, including development and review 
of SIP revisions, five-year progress reports, and the implementation of 
other programs having the potential to contribute to impairment of 
visibility in Class I areas.

VII. EPA's Evaluation of Wyoming's Regional Haze SIP

A. Affected Class I Areas

    Pursuant to 40 CFR 51.308(d), the State identified seven mandatory 
Class I areas in Wyoming: Grand Teton National Park, Yellowstone 
National Park, Bridger Wilderness, Fitzpatrick Wilderness, North 
Absaroka Wilderness, Teton Wilderness, and Washakie Wilderness.

B. Baseline Visibility, Natural Visibility, and Uniform Rate of 
Progress

    As required by 40 CFR 51.308(d)(2), Wyoming provided baseline 
visibility, natural visibility, and the URP for each Class I area in 
the State. Natural background visibility, as defined in our 2003 
Natural Visibility Guidance, is estimated by calculating the expected 
light extinction using default estimates of natural concentrations of 
fine particle components adjusted by site-specific estimates of 
humidity. This calculation uses the IMPROVE equation, which is a 
formula for estimating light extinction from the estimated natural 
concentrations of fine particle components (or from components measured 
by the IMPROVE monitors). As documented in our 2003 Natural Visibility 
Guidance, EPA allows states to use ``refined'' or alternative 
approaches to this guidance to estimate the values that characterize 
the natural visibility conditions of Class I areas.
    One alternative approach is to develop and justify the use of 
alternative estimates of natural concentrations of fine particle 
components. Another alternative is to use the ``new IMPROVE equation'' 
that was adopted for use by the IMPROVE Steering Committee in December 
2005.\9\ The purpose of this refinement to the ``old IMPROVE equation'' 
is to provide more accurate estimates of the various factors that 
affect the calculation of light extinction.
---------------------------------------------------------------------------

    \9\ The IMPROVE program is a cooperative measurement effort 
governed by a steering committee composed of representatives from 
Federal agencies (including representatives from EPA and the FLMs) 
and regional planning organizations. The IMPROVE monitoring program 
was established in 1985 to aid the creation of Federal and State 
implementation plans for the protection of visibility in Class I 
areas. One of the objectives of IMPROVE is to identify chemical 
species and emission sources responsible for existing anthropogenic 
visibility impairment. TheIMPROVE program has also been a key 
participant in visibility-related research, including the 
advancement of monitoring instrumentation, analysis techniques, 
visibility modeling, policy formulation and source attribution field 
studies.
---------------------------------------------------------------------------

    Wyoming used the new IMPROVE equation to calculate natural 
conditions and baseline visibility. The natural condition for each 
Class I area represents the visibility goal expressed in deciviews for 
the 20% worst days and the 20% best days that would exist if there were 
only naturally occurring visibility impairment. In accordance with 40 
CFR 51.308(d)(2)(iii), the State calculated natural visibility 
conditions based on available monitoring information and appropriate 
data analysis techniques and in accordance with our 2003 Natural 
Visibility Guidance. The State also calculated the number of deciviews 
by which baseline conditions exceed natural conditions at each of its 
Class I areas to meet the requirements of 40 CFR 51.308(d)(2)(iv)(A).
    Wyoming established the baseline visibility for the best and worst 
visibility days for each Class I area based on data from the IMPROVE 
monitoring sites. Each IMPROVE monitor collects particulate 
concentration data which are converted into reconstructed light 
extinction through a complex calculation using the IMPROVE equation 
(see Chapter 13 of the SIP for more information on reconstructed light 
extinction and the IMPROVE equation). Per 40 CFR 51.308(d)(2)(i), the 
State calculated baseline visibility using a five-year average (2000 to 
2004) of IMPROVE data for both the 20% best and 20% worst days. The 
State's baseline calculations were made in accordance with our 2003 
Tracking Progress Guidance.
    Pursuant to 40 CFR 51.308(d)(1)(i)(B), the State calculated the URP 
for each of its Class I areas. For the 20% worst days, the URP is the 
calculation of the deciview reduction needed to achieve natural 
conditions by 2064. For the 20% worst days, the State calculated the 
URP in deciviews per year using the following formula: URP = [Baseline 
Condition--Natural Condition]/60 years. In order to determine the 
uniform progress needed by 2018 to be on the path to achieving natural 
visibility conditions by 2064, the State multiplied the URP by the 14 
years in the first planning period (2004-2018).
    Table 1 shows the baseline visibility, natural conditions, and URP 
for each of the Class I areas. As indicated by the table, some Class I 
areas share a single monitor because of the proximity of the areas to 
each other.

                                   Table 1--Baseline Visibility, Natural Conditions, and URP for Wyoming Class I Areas
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             20% Worst Days                                                                20% Best Days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Reduction
                                                             2000-2004                       Needed to     2064 Natural        Delta         2000-2004
          Wyoming Class I areas            Monitor name      Baseline        2018 URP     Reach 2018 URP    Conditions    Baseline--2064     Baseline
                                                            (deciview)      (deciview)         (delta       (deciview)        Natural       (deciview)
                                                                                             deciview)                      Conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand Teton             YELL2            11.8            10.5             1.3            6.44            5.36            2.58
 National Park, Teton Wilderness........

[[Page 34746]]

 
North Absaroka Wilderness...............           NOABI            11.5            10.4             1.1            6.83            4.67            2.0
Washakie Wilderness.....................
Bridger Wilderness, Fitzpatrick                    BRID1            11.1            10.0             1.1            6.45            4.65            2.1
 Wilderness.............................
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We have reviewed Wyoming's baseline visibility, natural conditions, 
and URP. We find they have been calculated correctly and are proposing 
to approve them.

C. BART Determinations

    BART is an element of Wyoming's LTS for the first implementation 
period. As discussed in more detail in section VI.D of this notice, the 
BART evaluation process consists of three components: (1) An 
identification of all the BART-eligible sources; (2) an assessment of 
whether those BART-eligible sources are in fact subject-to-BART; and 
(3) a determination of any BART controls. Wyoming addressed these steps 
as follows:
1. BART-Eligible Sources
    The first step of a BART evaluation is to identify all the BART-
eligible sources within the state's boundaries. Wyoming identified its 
BART-eligible sources by using the approach set out in the BART 
Guidelines (70 FR 39158). This approach provides three criteria for 
identifying BART-eligible sources: (1) One or more emission units at 
the facility fit within one of the 26 categories listed in the BART 
Guidelines; (2) the emission unit or units began operation on or after 
August 6, 1962, and were in existence on August 6, 1977; and (3) 
combined potential emissions of any visibility-impairing pollutant from 
the units that meet the criteria in (1) and (2) are 250 tons or more 
per year. Wyoming reviewed source permits and emission data from 2001-
2003 to identify facilities in the BART source categories with 
potential emissions of 250 tons per year or more for any visibility-
impairing pollutant from any unit or units that were in existence on 
August 7, 1977 and began operation on or after August 7, 1962. The BART 
Guidelines direct states to address SO2\10\, NOX, 
and direct PM (including both PM10 and PM2.5) 
emissions as visibility-impairing pollutants and to exercise their 
``best judgment to determine whether VOC or NH3 emissions 
from a source are likely to have an impact on visibility in an area.'' 
(70 FR 39162).
---------------------------------------------------------------------------

    \10\ Wyoming has elected to submit its RH SIP pursuant to the 
requirements of 40 CFR 51.309. For states electing to submit under 
section 309, States do not have to do a BART analysis for 
SO2. SO2 controls are included in the backstop 
trading program under 40 CFR 51.309(d)(4).
---------------------------------------------------------------------------

    The State analyzed the emissions from VOC and NH3 from 
sources in the State and eliminated them from further consideration for 
BART controls. The State evaluated the BART-eligible sources and 
determined emissions of VOC and NH3 were negligible. Thus, 
the State has eliminated VOC and NH3 from further 
consideration for BART controls. We agree with the State that emissions 
of VOC and NH3 are negligible and propose to accept this 
determination.
    The State determined that the following were BART-eligible sources: 
PacifiCorp Jim Bridger, P4 Production, PacifiCorp Naughton, OCI 
Wyoming, FMC Granger, Dyno Nobel, FMC Westvaco, Sinclair Casper 
Refinery, Basin Electric Laramie River, Black Hills Neil Simpson 1, 
PacifiCorp Wyodak, Sinclair--Sinclair Refinery, PacifiCorp Dave 
Johnston, and General Chemical Green River.
    We have reviewed this information and propose to accept this 
determination.
2. Sources Subject-to-BART
    The second step of the BART evaluation is to identify those BART-
eligible sources that may reasonably be anticipated to cause or 
contribute to any visibility impairment at any Class I area, i.e., 
those sources that are subject-to-BART. The BART Guidelines allow 
states to consider exempting some BART-eligible sources from further 
BART review because they may not reasonably be anticipated to cause or 
contribute to any visibility impairment in a Class I area. Consistent 
with the BART Guidelines, Wyoming performed dispersion modeling on the 
BART-eligible sources to assess the extent of their contribution to 
visibility impairment at surrounding Class I areas.
a. Modeling Methodology
    The BART Guidelines provide that states may use the CALPUFF \11\ 
modeling system or another appropriate model to predict the visibility 
impacts from a single source on a Class I area and to, therefore, 
determine whether an individual source is anticipated to cause or 
contribute to impairment of visibility in Class I areas, i.e., ``is 
subject to BART.'' The Guidelines state that CALPUFF is the best 
regulatory modeling application currently available for predicting a 
single source's contribution to visibility impairment (70 FR 39162).
---------------------------------------------------------------------------

    \11\ Note that our reference to CALPUFF encompasses the entire 
CALPUFF modeling system, which includes the CALMET, CALPUFF, and 
CALPOST models and other pre and post processors. The different 
versions of CALPUFF have corresponding versions of CALMET, CALPOST, 
etc. which may not be compatible with previous versions (e.g., the 
output from a newer version of CALMET may not be compatible with an 
older version of CALPUFF). The different versions of the CALPUFF 
modeling system are available from the model developer at http://www.src.com/verio/download/download.htm.
---------------------------------------------------------------------------

    The BART Guidelines also recommend that states develop a modeling 
protocol for making individual source attributions, and suggest that 
states may want to consult with EPA and their RPO to address any issues 
prior to modeling. Wyoming used the CALPUFF model for Wyoming BART 
sources in accordance with a protocol it developed titled BART Air 
Modeling Protocol Individual Source Visibility Impairment Analysis, 
March 2006, which was approved by EPA and is included in Chapter 6 of 
the State's TSD. The Wyoming protocol follows

[[Page 34747]]

recommendations for long-range transport described in appendix W to 40 
CFR part 51, Guideline on Air Quality Models, and in EPA's Interagency 
Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and 
Recommendations for Modeling Long Range Transport Impacts as 
recommended by the BART Guidelines. (40 CFR part 51, appendix Y, 
section III.A.3). To determine if each BART-eligible source has a 
significant impact on visibility, Wyoming used the CALPUFF model to 
estimate daily visibility impacts above estimated natural conditions at 
each Class I area within 300 km of any BART-eligible facility. The 
emission rates used in the CALPUFF modeling were determined by Wyoming 
based upon existing permits, allowable rates, and emissions reporting 
data.
b. Contribution Threshold
    For states using modeling to determine the applicability of BART to 
single sources, the BART Guidelines note that the first step is to set 
a contribution threshold to assess whether the impact of a single 
source is sufficient to cause or contribute to visibility impairment at 
a Class I area. The BART Guidelines state that, ``[a] single source 
that is responsible for a 1.0 deciview change or more should be 
considered to `cause' visibility impairment.'' (70 FR 39104, 39161). 
The BART Guidelines also state that ``the appropriate threshold for 
determining whether a source contributes to visibility impairment may 
reasonably differ across states,'' but, ``[a]s a general matter, any 
threshold that you use for determining whether a source ``contributes'' 
to visibility impairment should not be higher than 0.5 deciviews.'' Id. 
Further, in setting a contribution threshold, states should ``consider 
the number of emissions sources affecting the Class I areas at issue 
and the magnitude of the individual sources' impacts.'' The Guidelines 
affirm that states are free to use a lower threshold if they conclude 
that the location of a large number of BART-eligible sources in 
proximity to a Class I area justifies this approach.
    Wyoming used a contribution threshold of 0.5 deciviews for 
determining which sources are subject-to-BART. By using a contribution 
threshold of 0.5 deciviews, Wyoming exempted seven of the fourteen 
BART-eligible sources in the State from further review under the BART 
requirements. Based on the modeling results, the State determined that 
P4 Production, FMC Granger,\12\ and OCI Wyoming had an impact of .07 
deciview, 0.39 deciview, and 0.07 deciview, respectively, at Bridger 
Wilderness. Black Hills Neil Simpson 1, Sinclair Casper Refinery, and 
Sinclair--Sinclair Refinery have an impact of 0.27 deciview, 0.06 
deciview, and 0.12 deciview, respectively, at Wind Cave. Dyno-Nobel had 
an impact of 0.22 deciview at Rocky Mountain National Park. These 
sources' modeled visibility impacts fell below the State's threshold of 
0.5 deciview and were determined not to be subject-to-BART.\13\ Given 
the relatively limited impact on visibility from these seven sources, 
we propose to agree with Wyoming that 0.5 deciviews is a reasonable 
threshold for determining whether its BART-eligible sources are 
subject-to-BART.
---------------------------------------------------------------------------

    \12\ The State of Wyoming performed a refined CALPUFF visibility 
modeling analysis for the two BART-eligible units at the FMC Wyoming 
Granger Facility and demonstrated that the predicted 98th percentile 
impacts at Bridger Wilderness Area and Fitzpatrick Wilderness Area 
would be below 0.5 dv for all meteorological periods modeled. This 
modeling used higher-resolution meteorological data as compared to 
the data used by the State for the initial screening modeling that 
identified the facility as subject-to-BART.
    \13\ CALPUFF modeling results, which provide the maximum change 
in visibility are summarized in the WY BART Screening Analysis 
Results and the WY BART Screening Analysis Results DV Frequency, 
which can also be found in Chapter 6 of the State's TSD.
---------------------------------------------------------------------------

    Because our recommended modeling approach already incorporates 
choices that tend to lower peak daily visibility impact values,\14\ our 
BART Guidelines state that a state should compare the 98th percentile 
(as opposed to the 90th or lower percentile) of CALPUFF modeling 
results against the ``contribution'' threshold established by the state 
for purposes of determining BART applicability. Wyoming used a 98th 
percentile comparison that we find appropriate. Further explanation on 
use of the 98th versus 90th percentile value is provided at 70 FR 
39121.
---------------------------------------------------------------------------

    \14\ See our BART Guidelines, Section III.A.3.
---------------------------------------------------------------------------

c. Sources Identified by Wyoming as Subject-to-BART
    Table 2 shows the sources identified by the State as subject-to-
BART and the results of the CALPUFF modeling. The results reflect the 
single highest impacted year.

[[Page 34748]]

  Table 2--Wyoming Subject-to-BART Sources and CALPUFF Modeling Results
------------------------------------------------------------------------
                                                         State modeling
                                                         results--98th
         Facility name          Subject-to-BART units  percentile  delta-
                                                            deciview
------------------------------------------------------------------------
PacifiCorp--Jim Bridger.......  Units 1-4............               3.1
Basin Electric--Laramie River.  Units 1, 2 and 3.....               3.68
PacifiCorp--Dave Johnston.....  Units 3 and 4........               3.30
PacifiCorp--Naughton..........  Units 1-3............               4.36
PacifiCorp--Wyodak............  Unit 1...............               1.66
FMC--Westvaco.................  Units NS-1A and NS-1B               1.3
General Chemical--Green River.  Boilers C and D......               1.36
------------------------------------------------------------------------

    We are proposing to approve the State's determination of the 
subject-to-BART sources.
3. BART Determinations and Federally Enforceable Limits
    The third step of a BART evaluation is to perform the BART 
analysis. The BART Guidelines (70 FR 39164) describe the BART analysis 
as consisting of the following five steps:
     Step 1: Identify All Available Retrofit Control 
Technologies;
     Step 2: Eliminate Technically Infeasible Options;
     Step 3: Evaluate Control Effectiveness of Remaining 
Control Technologies;
     Step 4: Evaluate Impacts and Document the Results; and
     Step 5: Evaluate Visibility Impacts.
    In determining BART, the State must consider the five statutory 
factors in section 169A of the CAA: (1) The costs of compliance; (2) 
the energy and non-air quality environmental impacts of compliance; (3) 
any existing pollution control technology in use at the source; (4) the 
remaining useful life of the source; and (5) the degree of improvement 
in visibility which may reasonably be anticipated to result from the 
use of such technology. See also 40 CFR 51.308(e)(1)(ii)(A).
    We find that Wyoming considered all five steps above in its BART 
determinations, but we propose to find that its consideration of the 
costs of compliance and visibility improvement for the EGUs was 
inadequate and did not properly follow the requirements in the BART 
Guidelines and statutory requirements, as explained below.
a. Costs of Compliance
    Wyoming obtained the costs of compliance for controls from the BART 
applications submitted by sources that were subject to BART.\15\ EPA in 
turn relied on these costs in our original proposed rule. EPA has 
reviewed Wyoming's cost analyses and has identified deficiencies in 
various cost assumptions and methods. Accordingly, EPA has subsequently 
and independently calculated costs of compliance and performed new 
visibility modeling. In many instances, the BART sources underestimated 
the cost of selective non-catalytic reduction (SNCR), while 
overestimating the cost of selective catalytic reduction (SCR) (both in 
combination with additional combustion controls). Depending on the 
particular BART source in question, we believe this was due to a number 
of errors, such as: use of incorrect baseline emissions; overestimation 
of the ability of SNCR to reduce NOX; underestimation of 
SNCR reagent (urea) usage and cost; and underestimation of the ability 
of SCR to reduce NOX.
---------------------------------------------------------------------------

    \15\ Attachment A to the Wyoming 309(g) Regional Haze SIP.
---------------------------------------------------------------------------

    EPA has identified a number of flaws in Wyoming's cost analyses for 
SNCR. For example, in the case of Laramie River Units 1-3, Wyoming 
significantly overestimated the ability of SNCR to reduce 
NOX. The analyses submitted by the source, and in turn used 
by Wyoming, assumed that after the installation of additional 
combustion controls, SNCR would reduce NOX from 0.23 lb/
MMBtu to 0.12 lb/MMBtu (or by roughly 48%). However, SNCR typically 
reduces NOX an additional 20 to 30% above combustion 
controls without excessive NH3 slip.\16\ NOX 
reduction with SNCR is known to be greater at higher NOX 
emission rates than lower rates.\17\ Accordingly, EPA has estimated 
that the NOX reduction from SNCR as 30% for initial 
NOX greater than 0.25 lb/MMBtu, 25% for NOX from 
0.20 to 0.25 lb/MMBtu and 20% for NOX less than 0.20 lb/
MMBtu.\18\ Due to the relatively recent installation of overfire air at 
the Laramie River units, the actual annual emissions in 2012 dropped to 
around 0.19 lb/MMBtu,\19\ even lower than the 0.23 lb/MMbtu rate 
assumed by Wyoming. Therefore, EPA predicts that the reduction that can 
be achieved with SNCR at the Laramie River units is 20%, which is much 
lower than the 48% assumed by Wyoming. This significantly reduces the 
tons reduced by SNCR which is in turn used in the calculation of cost 
effectiveness. It also affects the incremental cost effectiveness 
between SNCR and SCR (both in combination with additional combustion 
controls). In addition, our analysis of urea prices indicates that 
producer prices for urea have increased the past three years. This 
increase in price is not reflected in the Wyoming estimates for SNCR.
---------------------------------------------------------------------------

    \16\ White Paper, SNCR for Controlling NOX Emissions, 
Institute of Clean of Clean Air Companies, pp. 4 and 9, February 
2008.
    \17\ Hofmann, J., Sun, W., ``Process for Nitrogen Oxides 
Reduction to Lowest Achievable Level'', US Patent 5,229,090, July 
20, 1993, Figure 6.
    \18\ Review of Estimated Compliance Costs for Wyoming Electric 
Generating (EGUs)--Revision of Previous Memo, memo from Jim Staudt, 
Andover Technology Partners, to Doug Grano, EC/R, Inc., February 7, 
2013, page 7 (Staudt Memo).
    \19\ Staudt memo, Table 2, p. 7.
---------------------------------------------------------------------------

    EPA has also identified a number of flaws in Wyoming's cost 
analyses for SCR. For example, Wyoming assumed that SCR could only 
achieve a control effectiveness of 0.07 lb/MMBtu. By contrast, EPA has 
determined that on an annual basis SCR can achieve emission rates of 
0.05 lb/MMbtu or lower. Moreover, we note that Wyoming's SCR capital 
costs on a $/kW basis often exceeded real-world industry costs. The 
capital costs for SCR claimed by Wyoming for Dave Johnston 3 and 4, 
Naughton Units 1-3, and Wyodak are in excess of the range of capital 
costs documented by various studies for actual installations. Five 
industry studies conducted between 2002 and 2007 have reported the 
installed unit capital cost of SCRs, or the costs actually incurred by 
owners, to range from $79/kW to $316/kW (2010 dollars). By contrast, 
Wyoming's SCR costs range from $415/kW to $531/kW.\20\ These studies 
show actual capital costs are much lower than Wyoming's, particularly 
for the PacifiCorp units.
---------------------------------------------------------------------------

    \20\ Staudt memo, Table 1, p. 4.
---------------------------------------------------------------------------

    For all control technologies, EPA has identified instances in which

[[Page 34749]]

Wyoming's source-based cost analyses did not follow the methods set 
forth in the EPA Control Cost Manual.\21\ For example, Wyoming included 
an allowance for funds used during construction and for owners costs 
and did not provide sufficient documentation such as vendor estimates 
or bids.
---------------------------------------------------------------------------

    \21\ ``In order to maintain and improve consistency, cost 
estimates should be based on the OAQPS Control Cost Manual, where 
possible.'' 70 FR 39166.
---------------------------------------------------------------------------

    In addition, for the PacifiCorp units, Wyoming calculated the 
baseline annual emissions used for determining cost effectiveness based 
on allowable emissions, rated heat input, and 7,884 hours of operation 
(equivalent to a 85% capacity factor), which are not representative of 
actual emissions from the baseline period. By contrast, the BART 
Guidelines state that the baseline emissions should ``represent a 
realistic depiction of anticipated annual emissions for the source.'' 
\22\ Therefore, in our revised cost analyses, we have consistently used 
the actual annual average emissions from 2001-2003 to represent 
baseline emissions.
---------------------------------------------------------------------------

    \22\ 70 FR 39167.
---------------------------------------------------------------------------

    To address these flaws and deficiencies, EPA has developed 
independent cost analyses. In our revised cost analyses, we have 
followed the structure of the EPA Control Cost Manual, though we have 
largely used the Integrated Planning Model cost calculations to 
estimate direct capital costs and operating and maintenance costs. We 
have also followed the BART Guidelines. Detailed information on the 
revised costs can be found in the docket.23 24 In addition, 
we received comments on our original proposed rulemaking from the 
National Park Service and Conservation Organizations that expressed 
similar concerns with the State's cost analyses.
---------------------------------------------------------------------------

    \23\ Review of Estimated Compliance Costs for Wyoming Electric 
Generating (EGUs)--Revision of Previous Memo, memo from Jim Staudt, 
Andover Technology Partners, to Doug Grano, EC/R, Inc., February 7, 
2013. (Staudt Memo).
    \24\ Review of Estimated BART Compliance Costs for Wyoming 
Electricity Generating Units (EGUs) memo from Jim Staudt, Andover 
Technology Partners, to Doug Grano, EC/R, Inc., February 7, 2013.
---------------------------------------------------------------------------

b. Visibility Improvement Modeling
    The BART Guidelines provide that states may use the CALPUFF 
modeling system or another appropriate model to determine the 
visibility improvement expected at a Class I area from potential BART 
control technologies applied to the source. The BART Guidelines also 
recommend that states develop a modeling protocol for modeling 
visibility improvement, and suggest that states may want to consult 
with EPA and their RPO to address any issues prior to modeling. Wyoming 
developed a modeling protocol titled BART Air Modeling Protocol 
Individual Source Visibility Assessments for BART Control Analyses, 
September 2006, for sources to use when they performed their BART 
analysis (see Chapter 6 of the State's TSD). The Wyoming protocol 
follows recommendations for long-range transport described in appendix 
W to 40 CFR part 51, Guideline on Air Quality Models, and in EPA's 
Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary 
Report and Recommendations for Modeling Long Range Transport Impacts, 
as recommended by the BART Guidelines (40 CFR part 51, appendix Y, 
section III.D.5).
    While we are able to propose approval of the State's PM BART 
determinations without having additional visibility improvement 
modeling for PM controls, as discussed below, additional visibility 
improvement modeling to address the EGU NOX BART controls 
was needed and subsequently performed by EPA and presented in our 
original proposed rulemaking.\25\ Our additional modeling to support 
the original proposed rule was intended to addresses two deficiencies. 
First, while Wyoming took into consideration the degree of visibility 
improvement for some BART NOX control options for the 
PacifiCorp EGUs, such as SCR, they did not do so for SNCR. The 
visibility improvement for SNCR was neither provided in the State's SIP 
nor made available to EPA. Wyoming did not assess the visibility 
improvement of SNCR despite having found it to be a technically 
feasible control option, and having considered a number of the other 
statutory factors for SNCR, such as costs of compliance and energy 
impacts. Wyoming did not consider the visibility improvement associated 
with SNCR, which is clearly in conflict with the requirements set forth 
in section 169A(g)(2) of the CAA, as well as in the implementing 
regulations,\26\ which require that states take into consideration 
``the degree of improvement in visibility which may reasonably be 
anticipated to result from the use of such technology.'' Because 
Wyoming did not do so, and in order to be consistent with the statutory 
and regulatory requirements, EPA conducted additional CALPUFF modeling 
to fill this gap in the State's visibility analysis (that is, to assess 
the visibility improvement associated with SNCR).
---------------------------------------------------------------------------

    \25\ A summary of EPA's modeling methodology and results for the 
original proposed rulemaking can be found in the docket under EPA 
BART and RP Modeling for Wyoming Sources.
    \26\ 40 CFR 51.308(e)(1)(ii)(A).
---------------------------------------------------------------------------

    Second, it was not possible for EPA, or any other party, to 
ascertain the visibility improvement that would result from the 
installation of the various NOX control options because 
Wyoming modeled the emission reductions for multiple pollutants 
together in its SIP. In other words, because the visibility improvement 
associated with each of the State's control scenarios was due to the 
combined emission reductions associated with SO2, 
NOX, and PM controls, it was not possible to isolate what 
portion of the improvement was attributable to the NOX 
controls alone. In addition, because Wyoming varied SO2 and 
PM emission rates along with NOX emission rates, it was not 
possible to assess the incremental visibility improvement between the 
various NOX controls options. For these reasons, EPA 
conducted additional modeling for the EGUs in which we held 
SO2 and PM emission rates constant (reflecting the 
``committed controls'' identified by Wyoming), and varied only the 
NOX emission rate. This allowed us to isolate the degree of 
visibility improvement attributable to the NOX control 
technologies. The modeling which EPA performed to support our original 
proposed rule addressed these two deficiencies in the State's analysis.
    To support today's proposal, EPA has found it necessary to revise 
the CALPUFF modeling we performed in association with our original 
proposed rule. The revised modeling to support today's proposed rule is 
intended to address two additional issues that were raised by 
commenters during the comment period for the original proposed rule. 
First, as discussed above in section V.II, we have revised the costs of 
control submitted by the State. In the process of revising these costs, 
we have calculated a new removal efficiency for the control options 
under consideration to reflect updated assumptions about baseline 
emissions and control effectiveness.\27\
---------------------------------------------------------------------------

    \27\ See Staudt memos.
---------------------------------------------------------------------------

    In order to align our cost and modeling analyses, these removal 
efficiencies have been incorporated into our revised modeling. Second, 
the emission rates we relied on in our original proposed rule for both 
the baseline (i.e., pre-control) and post-control modeling scenarios 
were not consistent with the BART Guidelines. For pre-control emission 
rates, the BART Guidelines recommend that States use the 24-hour 
average actual

[[Page 34750]]

emission rate from the highest emitting day of the meteorological 
period modeled.\28\ By contrast, the visibility modeling performed by 
PacifiCorp, and subsequently submitted by the State and utilized by EPA 
in our original proposal, deviates from the BART Guidelines by using 
permit limits and the maximum rated heat input to derive the modeled 
emission rates. Similarly, the visibility modeling performed by Basin 
Electric, and subsequently submitted by the State and utilized by EPA 
in our original proposal, deviates from the BART Guidelines by using 
actual annual average heat input and actual annual average emission 
rates (on a lb/MMBtu basis) from 2001-2003 continuous emissions 
monitoring data to derive modeled emission rates. Furthermore, the BART 
Guidelines recommend that post-control emission rates be calculated as 
a percentage of pre-control emission rates.\29\ The visibility modeling 
performed by PacifiCorp and Basin Electric, and subsequently submitted 
by the State and utilized by EPA in our original proposal, deviates 
from the BART Guidelines by using post-control emission rates 
calculated in a similar manner to the pre-control emission rates. Our 
revised modeling remedies both of the issues identified by the 
commenters and is consistent with the requirements of the BART 
Guidelines. We have otherwise followed the procedures contained in the 
Wyoming BART Air Modeling Protocol. A summary of EPA's revised modeling 
methodology and results can be found in the docket.\30\
---------------------------------------------------------------------------

    \28\ The BART Guidelines, Section IV. (70 FR 39170) specify that 
the modeling should ``[u]se the 24-hour average actual emission rate 
from the highest emitting day of the meteorological period modeled 
(for the pre-control scenario)''.
    \29\ The BART Guidelines, Section IV. (70 FR 39170) specify that 
``[p]ost-control emission rates are calculated as a percentage of 
pre-control emission rates''.
    \30\ EPA's modeling results and a summary of EPA's modeling 
methodology can be found in the docket under Summary of EPA's 
Revised Modeling--Including Revisions from Previous Version Posted 
on 1/18/2013 and Results for Jim Bridger Units 1-4 and EPA's Revised 
Modeling Results; posted to the docket on February 11, 2013.
---------------------------------------------------------------------------

    Because Wyoming relied on visibility modeling methodologies that 
are inconsistent with the statutory and regulatory requirements, we do 
not consider Wyoming's analyses of visibility improvement for 
NOX BART to be reasonable. We propose to find that Wyoming's 
analyses are inconsistent with the statutory and regulatory requirement 
that Wyoming reasonably take into consideration ``the degree of 
improvement in visibility which may reasonably be anticipated to result 
from the use of such technology.'' Therefore, as discussed in more 
detail below, we are proposing to disapprove several of the State's 
NOX BART determinations that do not meet the requirements of 
the CAA and regional haze regulations because they are inconsistent 
with the visibility requirements.
c. Summary of BART Determinations and Federally Enforceable Limits
    For the subject-to-BART sources, the State provided BART analyses, 
as well as additional technical information and materials, in 
Attachment A to the SIP. Chapter 6 of the SIP provides a summary of the 
five-factor analyses. As noted above, for this proposed rulemaking, EPA 
performed cost analyses and NOX visibility improvement 
modeling for the control technology options analyzed for the subject-
to-BART EGU sources. We are presenting the BART analyses that we based 
our June 4, 2012 proposed rulemaking on, as well as EPA's revised BART 
analyses, reflecting our revised cost and visibility improvement 
modeling for the EGUs.
    EPA is proposing to approve the State's BART determinations for the 
following units because we have determined that the State's conclusions 
were reasonable despite the cost and visibility errors for the EGUs 
discussed earlier: NOX and PM BART for FMC Westvaco Unit NS-
1A and NS-1B; NOX and PM BART for General Chemical Green 
River Boiler C and Boiler D; \31\ PM BART for Basin Electric Laramie 
River Units 1, 2, and 3; PM BART for PacifiCorp Dave Johnston Unit 3; 
PM BART for PacifiCorp Dave Johnston Unit 4; NOX and PM BART 
(including reasonable progress controls) for PacifiCorp Jim Bridger 
Units 1-4; PM BART for PacifiCorp Naughton Units 1and 2; NOX 
and PM BART for Naughton Unit 3; and PM BART for PacifiCorp Wyodak Unit 
1. A summary of the State's and EPA's BART determination for each 
source is provided below.
---------------------------------------------------------------------------

    \31\ FMC Westvaco and General Chemical Green River are not EGUs 
and EPA did not identify the same cost and visibility improvement 
modeling issues as it did for the EGUs and are thus proposing to 
approve the State's BART analyses and determinations for these 
units.
---------------------------------------------------------------------------

    EPA is proposing to disapprove the State's NOX BART 
determinations and promulgate a FIP for the following units: PacifiCorp 
Dave Johnston Units 3 and 4; PacifiCorp Naughton Units 1 and 2; 
PacifiCorp Wyodak Unit 1; and Basin Electric Laramie River Units 1, 2, 
and 3. After re-analyzing the costs of control and visibility 
improvement associated with these units, we determined that the State's 
selection of NOX BART controls could not be supported, 
warranting a FIP. EPA's reasoning behind its own NOX BART 
determinations and emission limitations for these units can be found in 
section VIII.A of this notice.
i. FMC Westvaco--Units NS-1A and NS-1B
Background
    FMC's Westvaco facility is a trona mine and sodium products plant 
located in Sweetwater County, Wyoming. FMC Westvaco has two existing 
coal-fired boilers, Unit NS-1A and Unit NS-1B, that are subject to 
BART. Unit NS-1A and Unit NS-1B each have a design heat input rate of 
887 MMBtu/hr and were constructed in 1975. They are both wall-fired, 
wet-bottom boilers burning subbituminous coal. The State's BART 
determinations for these units can be found in Chapter 6.5.2 and 
Attachment A of the SIP.
NOX BART Determination
    Units NS-1A and NS-1B are currently controlled with combustion air 
control with a permit limit of 0.7 lb/MMBtu (3-hour rolling average). 
The State determined that low NOX burners (LNBs) and 
overfired air (OFA), LNBs and OFA with SNCR, and LNBs and OFA with SCR 
were all technically feasible for reducing NOX emissions at 
Unit NS-1A and NS-1B. The State did not identify any technically 
infeasible options. The State did not identify any energy or non-air 
quality environmental impacts that would preclude the selection of any 
of the controls evaluated, and there are no remaining-useful-life 
issues for this source. A summary of the State's NOX BART 
analyses and the visibility impacts is provided in Table 3. Baseline 
NOX emissions are 2,719.5 tpy for each unit based on a heat 
input rate of 887 MMBtu/hr and 8,760 hours of operation per year.

[[Page 34751]]

                                      Table 3--Summary of FMC Westvaco Unit NS-1A and Unit NS-1B NOX BART Analysis*
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                                                             (delta dv for
                                              (lb/MMBtu)  (30-      Emission                          Average cost    Incremental cost  the maximum 98th
             Control technology                  day rolling    reduction  (tpy)  Annualized costs    effectiveness     effectiveness      percentile
                                                  average)                                               ($/ton)                            impact at
                                                                                                                                             Bridger
                                                                                                                                        Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNB + OFA...................................              0.35          $1,359.7          $413,145              $304  ................              0.13
LNB + OFA + SNCR............................              0.21           1,903.6         1,281,851               673            $1,597              0.19
LNB + OFA + SCR.............................              0.10           2,331.0         8,141,177             3,493            16,051              0.24
--------------------------------------------------------------------------------------------------------------------------------------------------------
*This table reflects the costs and visibility improvements per boiler.

    The visibility modeling in the State's SIP only includes the 
visibility improvement at the two most impacted Class I areas: Bridger 
Wilderness Area and Fitzpatrick Wilderness Area. The visibility 
improvement at Bridger is listed in the Table above. For Fitzpatrick, 
the visibility improvement is .09 dv for LNBs with OFA, 0.11 dv for 
LNBs with SNCR, and 0.13 dv for LNBs with SCR. Given the limited 
visibility improvement at the two most impacted areas, we propose to 
find that it was reasonable for the State to model only those two 
receptors.
    Based on its consideration of the five factors, the State 
determined that LNBs plus OFA are reasonable for BART. The State 
determined that the other control options were not reasonable based on 
the cost effectiveness and associated visibility improvement. The State 
has determined that NOX BART emission limit for FMC Westvaco 
Unit NS-1A and Unit MS-1B is 0.35 lb/MMBtu (30-day rolling average).
    We agree with the State's conclusions, and we are proposing to 
approve its NOX BART determinations for FMC Westvaco Unit 
NS-1A and Unit NS-1B. Although the cost-effectiveness for SNCR is 
reasonable, we find it reasonable for the State not to select this 
control technology based on the incremental visibility improvement for 
this control technology.
PM BART Determination
    Unit NS-1A and Unit NS-1B are currently controlled for PM emissions 
by electrostatic precipitators (ESPs). The units each currently have a 
PM emission limit of 0.05 lb/MMBtu. The State determined that fabric 
filters on the wet scrubber, addition of an ESP downstream of the wet 
scrubber, and replacement of the ESPs with fabric filters were 
technically feasible control options. The State did not identify any 
energy or non-air quality environmental impacts that would preclude the 
selection of any of the controls evaluated, and there are no remaining-
useful-life issues for this source. A summary of the State's PM BART 
analysis is provided in Table 4 below. Baseline PM emissions are 197 
tpy for each unit based on a heat input rate of 887 MMBtu/hr and 8,760 
hours of operation per year.

                                      Table 4--Summary of FMC Westvaco Unit NS-1A and Unit NS-1B PM BART Analysis*
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Emission rate
                                                                    Control       (lb/mmbtu)  (30-      Emission                          Average cost
                      Control technology                        efficiency (%)      day rolling     reduction  (tpy)  Annualized costs    effectiveness
                                                                                      average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter on Wet Scrubber................................              21.4              0.04               41.7        $1,791,364           $42,948
ESP after Wet Scrubber.......................................              63.3              0.019             123.3         3,507,617            28,448
Replace ESP with Fabric Filter...............................              71.3              0.015             138.8         4,116,036            29,654
--------------------------------------------------------------------------------------------------------------------------------------------------------
*This table reflects the costs and visibility improvements per boiler.

    Given the high cost of controls, which are higher than what EPA, or 
other states have considered reasonable for PM, FMC did not evaluate 
the visibility improvement that would result from the PM controls 
evaluated. Previous visibility modeling analyses from the source 
indicate that the contribution in visibility degradation from PM is 
minor when compared to the effects of NOX and 
SO2. Results from FMC's visibility modeling screening and 
analysis confirm this conclusion and are discussed in further detail 
within the comprehensive visibility analysis included as part of FMC's 
BART application (see Attachment A to the SIP). The State agreed with 
FMC's conclusions and did not require FMC to perform additional 
visibility analyses for the PM control options.
    The State determined that the current ESP control was reasonable 
for PM BART. The State rejected other controls because of their high 
cost-effectiveness values. The State has determined that the PM BART 
emission limits for FMC Westvaco Unit NS-1A and NS-1B are 0.05 lb/
MMBtu, 45.0 lb/hr, and 197 tpy.
    We agree with the State's conclusions, and we are proposing to 
approve its PM BART determinations for FMC Westvaco Unit NS-1A and Unit 
NS-1B.
ii. General Chemical Green River--Boilers C and D
    General Chemical Green River is a trona mine and sodium products 
plant. General Chemical's two existing coal-fired boilers, C and D, are 
co-located at the facility power plant. Both boilers burn low sulfur 
bituminous coal, and they supply power and process steam to mining and 
ore processing operations. Both boilers are tangentially fired using 
in-line coal pulverizers. The firing rate is 534 MMBtu/hr for Boiler C 
and 880 MMBtu/hr for Boiler D. The State's BART determinations can be 
found in Chapter 6.5.3 and Attachment A of the SIP.
NOX BART Determination
    Boiler C and Boiler D are currently controlled with LNBs plus OFA 
with a permit limit of 0.7 lb/MMBtu (3-hour rolling average). On August 
7, 2009, the State issued a BART permit to General Chemical that 
required the source to meet a NOX emission limit of 0.32 lb/
MMBtu (30-day rolling average) for Boiler C and Boiler D. The State 
assumed the source could meet this

[[Page 34752]]

emission limit with the installation and operation of new LNBs with the 
existing OFA. Upon further investigation, the source determined it 
could not meet a limit of 0.32 lbs/MMBtu with new LNBs and the existing 
OFA.
    In response to the additional information provided by the source, 
the State reexamined its BART determination for Boiler C and D. The 
State determined that installing SOFA in addition to the existing LNBs 
and OFA could achieve an emission limit of 0.28 lb/MMBtu. Because SOFA 
in conjunction with the existing NOX controls could achieve 
better emission reductions than new LNBs plus OFA, the State eliminated 
the latter from further consideration in the BART analysis. The State 
determined that SNCR and SCR were also technically feasible. The State 
did not identify any technically infeasible options.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's NOX BART analysis and 
visibility impacts is provided in Tables 5 and 6 below. Baseline 
NOX emissions are 1,167 tpy for Boiler C and 1,816 tpy for 
Boiler D based on an average of 2001-2003 actual emissions.

                                      Table 5--Summary of General Chemical--Green River Boiler C NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                                                             (delta dv for
                                              (lb/MMBtu)  (30-      Emission                          Average cost    Incremental cost  the maximum 98th
             Control technology                  day rolling    reduction  (tpy)  Annualized costs    effectiveness     effectiveness      percentile
                                                  average)                                               ($/ton)                            impact at
                                                                                                                                             Bridger
                                                                                                                                        Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing LNBs with SOFA.....................              0.28               512          $757,711            $1,480                --              0.05
SNCR........................................              0.35               584         1,433,720             2,455            $4,782              0.08
SCR.........................................              0.14               934         2,434,809             2,607             3,156              0.14
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                      Table 6--Summary of General Chemical--Green River Boiler D NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                                                             (delta dv for
                                              (lb/MMBtu)  (30-      Emission                          Average cost    Incremental cost  the maximum 98th
             Control technology                  day rolling    reduction  (tpy)  Annualized costs    effectiveness     effectiveness      percentile
                                                  average)                                               ($/ton)                            impact at
                                                                                                                                             Bridger
                                                                                                                                        Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing LNBs with SOFA.....................               028               737          $943,549            $1,280                --              0.07
SNCR........................................              0.35               908         1,486,581             3,176            $2,913              0.12
SCR.........................................              0.14             1,453         3,399,266             3,510             4,342              0.17
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The visibility modeling in the State's SIP only includes the 
visibility improvement at the two most impacted Class I areas: Bridger 
Wilderness Area and Fitzpatrick Wilderness Area. The visibility 
improvement at Bridger is listed in the Table above. For Fitzpatrick, 
the visibility improvement is 0.10 dv for LNBs with SOFA, 0.09 for 
SNCR, and 0.12 dv for SCR for each unit. Given the limited visibility 
improvement at the two most impacted areas, we propose to find that it 
was reasonable for the State to model only those two receptors.
    Based on its consideration of the five factors, the State 
determined that NOX BART is the existing LNBs with new SOFA, 
or a comparable performing technology. The State determined that SNCR 
and SCR were not reasonable based on the high cost effectiveness and 
low visibility improvement. The State determined the NOX 
BART emission limit for General Chemical Green River Boiler C is 0.28 
lb/MMBtu (30-day rolling average) and that the NOX BART 
emission limit for Boiler D is 0.28 lb/MMBtu (30-day rolling average).
    We agree with the State's conclusions, and we are proposing to 
approve its NOX BART determinations for General Chemical 
Green River--Boiler C and D. Although the cost-effectiveness for SNCR 
and SCR is reasonable, we find it reasonable for the State not to 
select this control technology based on the low visibility improvement 
for these control technologies.
PM BART Determination
    Boilers C and D are currently controlled by ESPs with permit limits 
of 50 lb/hr and 80 lb/hr, respectively. General Chemical addressed PM 
emissions through an abbreviated analysis by using PM BART information 
from FMC Westvaco, as discussed above. The facilities are similar in 
size and located about ten miles apart. Baseline PM emissions are 98 
tpy for Boiler C and 161 tpy for Boiler D based on the average of 2001-
2003 actual emissions. As discussed above, visibility modeling 
screening and analyses for FMC Westvaco indicate that the contribution 
in visibility degradation from PM for a source comparable to Boiler C 
and Boiler D is minor. Additionally, costs for controlling PM from 
similar boilers are high as indicated by the FMC analysis for Westvaco.
    The State accepted General Chemical's abbreviated PM BART analysis. 
The State determined that the current ESP control was reasonable for PM 
BART. The State rejected other controls because of their high cost-
effectiveness values. The State determined that the PM BART emission 
limits for Boiler C are 0.09 lb/MMBtu, 50 lb/hr, and 219 tpy, and that 
the PM BART emissions limits for Boiler D are 0.09 lb/MMBtu, 80 lb/hr, 
and 350.4 tpy.
    We agree with the State's conclusions, and we are proposing to 
approve its PM BART determination for General Chemical Green River 
Boiler C and D.
iii. Basin Electric Laramie River Station--Units 1-3
    Basin Electric Laramie River Station is located in Platte County, 
Wyoming. Laramie River Station is comprised of three 550 MW dry-bottom, 
wall-fired boilers (Units 1, 2, and 3) burning

[[Page 34753]]

subbituminous coal for a total net generating capacity of 1,650 MW. All 
three units are subject-to-BART. The State's BART determination can be 
found in Chapter 6.5.8 and Attachment A of the SIP (The NOX 
BART analysis is discussed in section VIII.A of this notice).
PM BART Determination
    Laramie River Units 1, 2, and 3 are currently controlled with ESPs, 
each with a permit limit of 0.03 lb/MMBtu. The State determined that 
fabric filters were technically feasible for Unit 3 but not Units 1 and 
2. Units 1 and 2 are controlled with wet flue gas desulfurization and 
fabric filters cannot be used downstream of such a system. The State 
determined that flue gas treatment and GE Max-9 hybrid were technically 
infeasible for all three units. Thus, the only technically feasible 
control option for PM is fabric filters on Unit 3.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's PM BART analysis for Unit 3 is 
provided in Table 7 below. Baseline PM emissions are 716 tpy for the 
unit based on 2001-2003 actual emissions.

                                        Table 7--Summary of Basin Electric Laramie River Unit 3 PM BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Emission rate
                                                                     Control       (lb/MMBtu) (30-      Emission                          Average cost
                      Control technology                         efficiency  (%)     day rolling    reduction  (tpy)  Annualized costs    effectiveness
                                                                                      average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter--Peak Rate for Lost Generating Costs............                50             0.015               358      $194,809,000           $54,707
Fabric Filter Non-Peak Rate for Lost Generating Costs.........                50             0.015               358       134,934,000            40,156
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State did not provide visibility improvement modeling for 
fabric filters, but EPA is proposing to conclude this is reasonable 
based on the high cost-effectiveness of fabric filters at each of the 
units, which is higher than EPA or other state have considered 
reasonable for PM BART.
    Based on its consideration of the five factors, the State 
determined that the current ESPs are reasonable for PM BART, as fabric 
filters on Unit 3 are not cost-effective and there are no other 
technically feasible controls for Units 1 and 2. The State determined 
that the PM BART emission limit for each of the Laramie River Units 1, 
2, and 3 is 0.03 lb/MMBtu.
    We agree with the State's conclusions, and we are proposing to 
approve its PM BART determination for Basin Electric Laramie River 
Units 1, 2, and 3.
iv. PacifiCorp Dave Johnston--Units 3 and 4
Background
    PacifiCorp's Dave Johnston power plant is located in Converse 
County, Wyoming. Dave Johnston Power Plant is comprised of four units 
burning pulverized subbituminous Powder River Basin coal. Units 3 and 4 
are the only units subject-to-BART. Dave Johnston Unit 3 is a nominal 
230 MW pulverized coal-fired boiler that commenced service in 1964. It 
was equipped with burners in a cell configuration until 2010, but was 
then converted to a dry bottom wall-fired boiler. Dave Johnston Unit 4 
is a nominal 330 MW pulverized coal-fired boiler that commenced service 
in 1972. It is a tangential-fired boiler. The State's BART analysis can 
be found in Chapter 6.5.5 and Appendix A of the SIP (the NOX 
BART determination for Dave Johnston Unit 3 and Unit 4 is discussed in 
section VIII.A of this notice).
PM BART Determination
    Units 3 and 4 are currently controlled with fabric filters 
installed in 2008 with an emission limit of 0.015 lb/MMBtu. The State 
determined that fabric filters represent the most stringent PM control 
technology and that 0.015 lb/MMBtu is the most stringent emission 
limit. Consistent with the BART Guidelines, the State did not provide a 
five-factor analysis because the State determined BART to be the most 
stringent control technology and limit available (70 FR 39165). The 
State determined that the PM BART emission limits for Unit 3 and 4 are 
both 0.015 lb/MMBtu.
    We agree with the State's conclusions, and we are proposing to 
approve its PM BART determination for Dave Johnston Units 3 and 4.
v. PacifiCorp Jim Bridger--Units 1-4
Background
    PacifiCorp's Jim Bridger Power Plant is located in Sweetwater 
County, Wyoming. Jim Bridger is comprised of four identically sized 
nominal 530 MW tangentially fired boilers burning pulverized coal for a 
total net generating capacity of 2,120 MW. Jim Bridger Unit 1 was 
placed in service in 1974, Unit 2 in 1975, Unit 3 in 1976, and Unit 4 
in 1979. The State's BART determination can be found in Chapter 6.5.4 
and Appendix A of the SIP.
Wyoming's NOX BART Determination for Jim Bridger Unit 1 and 
Unit 2
    During the baseline period of 2001-2003, PacifiCorp Jim Bridger 
Units 1 and 2 were equipped with early generation LNBs with permit 
limits of 0.70 lb/MMBtu (3-hour fixed) and 0.42 lb/MMBtu and 0.40 lb/
MMBtu (annual limit), respectively. The State determined that new LNBs 
with SOFA, new LNBs with SOFA plus SNCR, and new LNBs with SOFA plus 
SCR were all technically feasible for controlling NOX 
emissions. The State did not identify any technically infeasible 
options.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, nor are there any remaining-useful-life issues for 
this source. Baseline NOX emissions are 10,643 tpy for each 
unit based on unit heat input rate of 6,000 MMBtu/hr and 7,884 hours of 
operation. A summary of the State's NOX BART analysis and 
the visibility impacts is provided in Table 8 below.\32\
---------------------------------------------------------------------------

    \32\ We are assuming the same costs for Unit 2 as the other Jim 
Bridger Units. The State analyzed Unit 2 using post installation of 
LNBs/OFA costs so the cost information provided in their analysis is 
not consistent with an uncontrolled baseline.

[[Page 34754]]

                               Table 8--Summary of Wyoming's Jim Bridger Units 1 and 2 NOX BART Analysis--Costs per Boiler
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                                                            (delta deciview
                                               (lb/MMBtu) (30-      Emission                          Average cost    Incremental cost   for the maximum
             Control technology                  day rolling    reduction  (tpy)  Annualized costs    effectiveness     effectiveness    98th percentile
                                                  average)                                               ($/ton)                          impact at Mt.
                                                                                                                                             Zirkel
                                                                                                                                           wilderness)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNB with SOFA...........................              0.26             4,493        $1,144,969              $255                --         0.41/0.47
New LNB with SOFA and SNCR..................              0.20             5,913         2,710.801               459            $1,103         0.52/0.62
New LNB with SOFA and SCR...................              0.07             8,987        20,296,400             2,258             5,721         0.76/0.82
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on its consideration of the five factors, the State 
determined new LNBs with SOFA was reasonable for NOX BART. 
The State determined the NOX BART emission limit for Jim 
Bridger Units 1and 2 is 0.28 lb/MMBtu (30-day rolling average).
    PacifiCorp is required to install additional controls under the 
State's LTS. The State determined that based on the cost of compliance 
and visibility improvement presented by PacifiCorp in the BART 
applications for Jim Bridger Units 1 and 2 and taking into 
consideration the logistical challenge of managing multiple pollution 
control installations within the regulatory time allotted for 
installation of BART by the RHR, additional controls would be required 
under the LTS in order to achieve reasonable progress but would not be 
requires as BART. With respect to Jim Bridger Units 1 and 2, the State 
has required PacifiCorp to install SCR, or other NOX control 
systems, to achieve an emission limit of 0.07 lb/MMBtu on a 30-day 
rolling average. As part of Wyoming's Regional Haze plan, PacifiCorp is 
required to meet the 0.07 lb/MMBtu emission rate on Unit 1 prior to 
December 31, 2021 and on Unit 2 prior to December 31, 2022.
EPA's PacifiCorp Jim Bridger Units 1 and 2 NOX BART 
Determination
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. Baseline NOX emissions are 8,426 tpy for Unit 1 
and 7,577 for Unit 2 based on the actual annual average for the years 
2001-2003. A summary of the EPA's NOX BART analysis and the 
visibility impacts is provided in Tables 9-12 below. The cost 
effectiveness values for the Jim Bridger units vary considerably for 
the same control option. This is largely due to differences in the 
(actual) baseline emissions.

                                             Table 9--Summary of EPA's Jim Bridger Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                         Average cost                        (delta dv for
             Control technology                  (lb/MMBtu)         Emission      Annualized costs    effectiveness   Incremental cost  the maximum 98th
                                              (annual average)  reduction  (tpy)                         ($/ton)        effectiveness      percentile
                                                                                                                                          impact at Mt.
                                                                                                                                             Zirkel)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA...........................              0.18             4,558        $1,167,297              $256                --              0.59
New LNBs with OFA and SNCR..................              0.14             5,332         4,402,757               826            $4,182              0.69
New LNBs with OFA and SCR...................              0.05             7,352        17,592,636             2,393             6,530              0.96
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Jim Bridger Unit 1 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 10 
below.

                   Table 10--Jim Bridger Unit 1: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - New     impact) - New     impact) - New
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Bridger...................................................              0.53              0.62              0.91
Fitzpatrick...............................................              0.22              0.26              0.36
Rawah.....................................................              0.59              0.70              0.96
Rocky Mountain............................................              0.50              0.58              0.79
Grand Teton...............................................              0.17              0.19              0.27
Teton.....................................................              0.16              0.19              0.26
Washakie..................................................              0.18              0.21              0.27
Yellowstone...............................................              0.23              0.15              0.26
----------------------------------------------------------------------------------------------------------------

[[Page 34755]]

                                             Table 11--Summary of EPA's Jim Bridger Unit 2 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                         Average cost                        (delta dv for
             Control technology                  (lb/MMBtu)         Emission      Annualized costs    effectiveness   Incremental cost  the maximum 98th
                                              (annual average)  reduction  (tpy)                         ($/ton)        effectiveness      percentile
                                                                                                                                          impact at Mt.
                                                                                                                                             Zirkel)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA...........................              0.19             3,787        $1,167,297              $308                --              0.55
New LNBs with OFA and SNCR..................              0.15             4,545         4,360,958               959            $4,214              0.65
New LNBs with OFA and SCR...................              0.05             6,554        19,757,979             3,015             7,664              0.95
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Jim Bridger Unit 2 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 12 
below.

                   Table 12--Jim Bridger Unit 2: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Bridger...................................................              0.48              0.58              0.89
Fitzpatrick...............................................              0.21              0.25              0.36
Rawah.....................................................              0.46              0.48              0.78
Rocky Mountain............................................              0.38              0.46              0.68
Grand Teton...............................................              0.15              0.18              0.26
Teton.....................................................              0.15              0.18              0.25
Washakie..................................................              0.17              0.20              0.27
Yellowstone...............................................              0.15              0.18              0.26
----------------------------------------------------------------------------------------------------------------

    As discussed in detail above, because Wyoming relied on visibility 
modeling methodologies that are inconsistent with the statutory and 
regulatory requirements, we do not consider Wyoming's analysis of 
visibility improvement for the NOX BART to be reasonable for 
Wyodak Unit 1. We propose to find that Wyoming's analysis for this Unit 
is inconsistent with the statutory and regulatory requirement that 
``the degree of improvement in visibility which may reasonably be 
anticipated to result from the use of such technology.''
    Also, we are not relying on the State's costs due to reasons stated 
in section VII.C.3.b of this notice. We propose to find that Wyoming 
did not properly or reasonably ``take into consideration the costs of 
compliance.''
    Our analysis follows our BART Guidelines. With the exception of the 
NOX emission limits, the visibility improvement analyses, 
and the cost effectiveness analyses, EPA is proposing to find that the 
Wyoming RH BART analysis NOX for Dave Johnson Units 4 
fulfills all the relevant requirements of CAA Section 169A and the RHR.
    PacifiCorp asserted to the State during formulation of the SIP 
proposal, and has since asserted directly to EPA \33\, that a number of 
factors, when considered together, suggest that requiring installation 
of SCR at Jim Bridger Units 1 and 2 earlier than 2021-2022 is not 
reasonable. First, PacifiCorp points to the large number of retrofit 
actions it is taking at 20 coal-fired electric generating units in 
Wyoming, Utah, Colorado, and Arizona in order to reduce their 
emissions.\34\ These retrofits are intended to comply with the 
requirements in the regional haze SIPs that these states have submitted 
to EPA and with other regulatory requirements, including required 
controls for mercury and acid gases under the recent Mercury and Air 
Toxics Standards rule. The company asserts that there are high capital 
costs for the measures required for these air quality-improving 
retrofits. Moreover, PacifiCorp states that accelerating the required 
installation of SCR at Jim Bridger Units 1 and 2 to late 2017, rather 
than the 2021 and 2022 dates established by the State, would 
significantly increase the costs to the utility and to its customers.
---------------------------------------------------------------------------

    \33\ See July 12, 2012 letter from PacifiCorp to EPA Region 8 
located in the docket for this notice.
    \34\ For a listing of PacifiCorp's retrofit actions, see Table 1 
of Exhibit A--PacifiCorp's Emissions Reductions Plan in Chapter 6 of 
the State's TSD.
---------------------------------------------------------------------------

    In addition, the company asserts that it has designed the 
installation schedule in order to minimize the number of units that are 
out of service system wide for installation of emissions controls at 
any one time. Its goal, it asserts, is to be able to maintain service 
to its customers with an adequate capacity margin. The company asserts 
that accelerating the timeline for installation of SCR would upset the 
orderly shut-down schedule they have devised and would threaten both 
service interruptions and an increased risk of spot-purchases of more 
expensive electrical energy, if it is available, to serve customers, 
but that either eventuality would significantly increase costs to its 
customers.\35\
---------------------------------------------------------------------------

    \35\ See Exhibit A--PacifiCorp's Emissions Reductions Plan in 
Chapter 6 of the State's TSD.
---------------------------------------------------------------------------

    EPA notes that PacifiCorp has offered these assertions taking into 
account only the requirements in the SIPs that have been submitted to 
EPA by Wyoming, Utah, Colorado, and Arizona. Today's proposal includes 
requirements that would likely require the additional installation of 
SCRs at three units and SNCR at two units owned by PacifiCorp

[[Page 34756]]

in Wyoming. In addition, we have since finalized action on the SIP for 
Arizona, and are requiring LNBs plus SCR on three units under a FIP.
    As stated in the BART Guidelines pertaining to affordability: ``1. 
Even if the control technology is cost effective, there may be cases 
where the installation of controls would affect the viability of 
continued plant operations. 2. There may be unusual circumstances that 
justify taking into consideration the conditions of the plant and the 
economic effects of requiring the use of a given control technology. 
These effects would include effects on product prices, the market 
share, and profitability of the source. Where there are such unusual 
circumstances that are judged to affect plant operations, you may take 
into consideration the conditions of the plant and the economic effects 
of requiring the use of a control technology. Where these effects are 
judged to have a severe impact on plant operations you may consider 
them in the selection process, but you may wish to provide an economic 
analysis that demonstrates, in sufficient detail for public review, the 
specific economic effects, parameters, and reasoning. (We recognize 
that this review process must preserve the confidentiality of sensitive 
business information). Any analysis may also consider whether other 
competing plants in the same industry have been required to install 
BART controls if this information is available.'' 40 CFR part 50, 
Appendix Y, IV.E.3.
    Based on the points made by PacifiCorp and noting the additional 
requirements in the proposed FIP for Wyoming, the finalized FIP for 
Arizona, and the possibility of additional requirements in a future FIP 
or SIP for Utah, EPA is proposing that the additional time to install 
controls under the State's LTS on Jim Bridger Unit 1 and Unit 2 is 
warranted under the affordability provisions in the BART Guidelines 
discussed above. Although neither the CAA nor the RHR require states or 
EPA to consider the affordability of controls or ratepayer impacts as 
part of a BART analysis, the BART guidelines allow (but do not require) 
consideration of ``affordability'' in the BART analysis.
    EPA is proposing to determine that BART for all units at Jim 
Bridger would be SCR if the units were considered individually, based 
on the five factors, without regard for the controls being required at 
other units in the PacifiCorp system. However, when the cost of BART 
controls at other PacifiCorp-owned EGUs is considered as part of the 
cost factor for the Jim Bridger Units, EPA is proposing that Wyoming's 
determination that NOX BART for these units is new LNB plus 
OFA for is reasonable. Considering costs broadly, it would be 
unreasonable to require any further retrofits at this source within 
five years of our final action. We note that the CAA establishes five 
years at the longest period that can be allowed for compliance with 
BART emission limits.
    EPA is proposing to approve the SIP with regard to the State's 
determination that the appropriate level of NOX control for 
Units 1 and 2 at Jim Bridger for purposes of reasonable progress is the 
SCR-based emission limit in the SIP, with compliance dates of December 
31, 2021 for Unit 2 and December 31, 2022 for Unit 1. In the context of 
reasonable progress in the second planning period of the regional haze 
program, we have determined it is appropriate to give considerable 
deference to the State's conclusions about what controls are reasonable 
and when they should be implemented. Thus, we do not find it 
appropriate to disapprove the State's preferred compliance deadlines 
for Jim Bridger Units 1 and 2. As discussed below, we are seeking 
comment on an alternative proposal to promulgate a FIP for PacifiCorp 
Jim Bridger Units 1 and 2.
Wyoming's NOX BART Determination for Jim Bridger Units 3 and 
4
    During the 2001-2003 baseline period, PacifiCorp Jim Bridger Units 
3 and 4 were equipped with early generation LNBs with permit limits of 
0.70 lb/MMBtu (3-hour fixed) and 0.41 lb/MMBtu and 0.45 lb/MMBtu 
(annual), respectively. The State determined that new LNBs with SOFA, 
new LNBs with SOFA plus SNCR, and new LNBs with SOFA plus SCR were 
technically feasible for controlling NOX emissions. The 
State did not identify any technically infeasible options.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. Baseline NOX emissions are 10,643 tpy for each 
unit based on unit heat input rate of 6,000 MMBtu/hr and 7,884 hours of 
operation.
    A summary of the State's NOX BART analysis and the 
visibility impacts is provided in Table 13 below.

                              Table 13--Summary of Wyoming's Jim Bridger Units 3 and 4 NOX BART Analysis--Costs per Boiler
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                                                            (delta deciview
                                               (lb/MMBtu) (30-      Emission                          Average cost    Incremental cost   for the maximum
             Control technology                  day rolling    reduction  (tpy)  Annualized costs    effectiveness     effectiveness    98th percentile
                                                  average)                                               ($/ton)                          impact at Mt.
                                                                                                                                             Zirkel
                                                                                                                                        Wilderness) \36\
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNB with SOFA...........................              0.26             4,493        $1,144,969              $255                --         0.41/0.47
New LNB with SOFA and SNCR..................              0.20             5,913         2,710.801               459            $1,103         0.53/0.62
New LNB with SOFA and SCR...................              0.07             8,987        20,296,400             2,258             5,721         0.80/0.82
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State determined that new LNBs with SOFA were reasonable for 
NOX BART for Jim Bridger Units 3 and 4. The State determined 
that the NOX BART emission limits for Jim Bridger Units 3 
and 4 are both 0.26 lb/MMBtu (30-day rolling average). As explained 
below, the State determined SCR was not reasonable for BART.
---------------------------------------------------------------------------

    \36\ Unit 4 has different modeling results as the stack 
parameters used in the modeling are different enough from Units 1-3 
to yield different modeled results.
---------------------------------------------------------------------------

    The State is requiring PacifiCorp to install SCR controls under its 
LTS. The State determined that based on the cost of compliance and 
visibility improvement presented by PacifiCorp in the BART applications 
for Jim Bridger Units 3 and 4 and taking into consideration the 
logistical challenge of managing multiple pollution control 
installations within the regulatory time

[[Page 34757]]

allotted for installation of BART by the RHR, SCR controls would be 
required under the LTS but not BART (see Chapter 8.3.3 of the SIP). 
With respect to Jim Bridger Units 3 and 4, the State has required 
PacifiCorp to install SCR, or other NOX control systems, to 
achieve an emission limit of 0.07 lb/MMBtu (30-day rolling average). 
PacifiCorp is required to meet the 0.07 lb/MMBtu emission rate on Unit 
3 prior to December 31, 2015 and on Unit 4 prior to December 31, 2016.
EPA's NOX BART Determination for Jim Bridger Unit 3 and Unit 
4
    The EPA agrees with the State's analysis pertaining to energy and 
non-air quality environmental impacts and remaining-useful-life for 
this source. EPA determined that baseline NOX emissions are 
7,853 tpy for Unit 3 and 8,133 tpy for Unit 4 based on the actual 
annual average for the years 2001-2003 (compared to 10,643 tpy that 
Wyoming relied on as noted above). As explained above, Wyoming 
determined that taking into consideration the logistical challenge of 
managing multiple pollution control installations within the regulatory 
time allotted for installation of BART by the RHR, SCR controls would 
be required under the LTS but not BART. A summary of the EPA's 
NOX BART analysis and the visibility impacts is provided in 
Tables 14-17 below.

                                             Table 14--Summary of EPA's Jim Bridger Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                         Average cost                        (delta dv for
             Control technology                  (lb/MMBtu)         Emission      Annualized costs    effectiveness   Incremental cost  the maximum 98th
                                              (annual average)  reduction  (tpy)                         ($/ton)        effectiveness      percentile
                                                                                                                                          impact at Mt.
                                                                                                                                             Zirkel)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with SOFA..........................              0.20             3,710        $1,167,297              $315                --              0.50
New LNBs with SOFA and SNCR.................              0.16             4,539         4,530,069               998            $4,058              0.61
New LNBs with SOFA and SCR..................              0.05             6,799        20,135,420             2,961             6,905              0.92
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Jim Bridger Unit 3 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 15 
below.

                   Table 15--Jim Bridger Unit 3: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + SOFA    LNBs + SOFA/SNCR   LNBs + SOFA/SCR
----------------------------------------------------------------------------------------------------------------
Bridger...................................................              0.43              0.54              0.87
Fitzpatrick...............................................              0.19              0.23              0.34
Rawah.....................................................              0.41              0.51              0.75
Rocky Mountain............................................              0.34              0.42              0.65
Grand Teton...............................................              0.14              0.17              0.25
Teton.....................................................              0.14              0.17              0.24
Washakie..................................................              0.22              0.19              0.26
Yellowstone...............................................              0.24              0.16              0.25
----------------------------------------------------------------------------------------------------------------

                                             Table 16--Summary of EPA's Jim Bridger Unit 4 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                         Average cost                        (delta dv for
             Control technology                  (lb/MMBtu)         Emission      Annualized costs    effectiveness   Incremental cost  the maximum 98th
                                              (Annual Average)  reduction  (tpy)                         ($/ton)        effectiveness      percentile
                                                                                                                                          impact at Mt.
                                                                                                                                             Zirkel)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with SOFA..........................              0.19             4,161        $1,167,297              $281                --              0.63
New LNBs with SOFA and SNCR.................              0.15             4,956         4,445,990               897            $4,127              0.75
New LNBs with SOFA and SCR..................              0.05             7,108        17,712,336             2,492             6,165              1.01
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Jim Bridger Unit 4 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 17 
below.

[[Page 34758]]

                   Table 17--Jim Bridger Unit 3: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + SOFA    LNBs + SOFA/SNCR   LNBs + SOFA/SCR
----------------------------------------------------------------------------------------------------------------
Bridger...................................................              0.56              0.68              1.00
Fitzpatrick...............................................              0.23              0.27              0.39
Rawah.....................................................              0.45              0.53              0.71
Rocky Mountain............................................              0.42              0.50              0.75
Grand Teton...............................................              0.18              0.21              0.30
Teton.....................................................              0.15              0.18              0.27
Washakie..................................................              0.19              0.23              0.29
Yellowstone...............................................              0.17              0.20              0.29
----------------------------------------------------------------------------------------------------------------

    As discussed in detail above, because Wyoming relied on visibility 
modeling methodologies that are inconsistent with the statutory and 
regulatory requirements, we do not consider Wyoming's analysis of 
visibility improvement for the NOX BART to be reasonable for 
Jim Bridger Unit 3 and 4. We propose to find that Wyoming's analysis 
for this Unit is inconsistent with the statutory and regulatory 
requirement that ``the degree of improvement in visibility which may 
reasonably be anticipated to result from the use of such technology.''
    Also, we are not relying on the State's costs due to reasons stated 
in section VII.C.3.b of this notice. We propose to find that Wyoming 
did not properly or reasonably ``take into consideration the costs of 
compliance.''
    Our analysis follows our BART Guidelines. With the exception of the 
NOX emission limits, the visibility improvement analyses, 
and the cost effectiveness analyses, EPA is proposing to find that the 
Wyoming regional haze BART analysis NOX for Jim Bridger 
Units 3 and 4 fulfills all the relevant requirements of CAA Section 
169A and the RHR.
    As stated above for Jim Bridger Units 1 and 2, EPA is proposing to 
determine that the facts indicate that BART for the all units at Jim 
Bridger is SCR when the units are considered individually based on the 
five factors without regard to the status of those factors for other 
units in the PacifiCorp system. However, when the five factors are 
considered across all the units, EPA is proposing that BART for Jim 
Bridger Units 3 and 4 is new LNB plus OFA.
    EPA is proposing to approve the SIP with regard to the State's 
determination that the appropriate level of NOX control for 
Units 3 and 4 at Jim Bridger for purposes of reasonable progress is the 
SCR-based emission limit in the SIP of 0.07 lb/MMBtu, with compliance 
dates of December 31, 2015 for Unit 3 and December 31, 2016 for Unit 4. 
As discussed above for Jim Bridger Units 1 and 2, in the context of 
reasonable progress in the second planning period of the regional haze 
program, we have determined it is appropriate to give considerable 
deference to the State's conclusions about what controls are reasonable 
and when they should be implemented. Thus, we do not find it 
appropriate to disapprove the State's preferred compliance deadlines 
for Jim Bridger Units 3 and 4. In addition, the State is requiring 
PacifiCorp to install the LTS controls within the timeline that BART 
controls would have to be installed pursuant to 40 CFR 51.308(e)(iv). 
Thus, we are proposing to approve the State's compliance schedule and 
emission limit of 0.07 lb/MMBtu for Jim Bridger Units 3 and 4 as 
meeting the BART requirements.
PM BART Determination for Jim Bridger Units 1-4
    Units 1, 2, 3, and 4 are currently controlled for PM with ESPs and 
flue gas conditioning (FGC). The current permit limit for all four 
units is 0.03 lb/MMBtu. The State determined that fabric filters were 
technically feasible for controlling PM emissions. The State did not 
identify any technically infeasible controls or any energy or non-air 
quality environmental impacts that would preclude the selection of any 
of the controls evaluated. There are no remaining-useful-life issues 
for this source. A summary of the State's PM BART analyses for Units 1-
4 is provided in Table 18 below. Baseline PM emissions are 1,064 tpy 
for Unit 1, 1,750 tpy for Unit 2, 1,348 tpy for Unit 3, and 710 tpy for 
Unit 4 based on unit heat input rate of 6,000 MMBtu/hr and 7,884 hours 
of operation per year.

                                    Table 18--Summary of Wyoming's PacifiCorp Jim Bridger Units 1-4 PM BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Emission rate
                                                                     Control      (lb/MMBtu)  (30-      Emission                          Average cost
                      Control technology                         efficiency  (%)     day rolling    reduction  (tpy)  Annualized costs    effectiveness
                                                                                      average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter--Unit 1.........................................              66.6             0.015               709        $6,367,118            $8,980
Fabric Filter--Unit 2.........................................              79.7             0.015             1,395         6,357,658             4,557
Fabric Filter--Unit 3.........................................              73.7             0.015               993         6,337,434             6,382
Fabric Filter--Unit 4.........................................                50             0.015               355         6,367,118            17,936
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State did not provide visibility improvement modeling for 
fabric filters, but EPA is proposing to conclude this is reasonable 
based on the high cost for fabric filters at each of the units. In 
addition, we anticipate that the visibility improvement that would 
result from lowering the limit from 0.03 lb/MMBtu to 0.015 lb/MMBtu 
would be

[[Page 34759]]

insignificant based on the State's analysis.\37\
---------------------------------------------------------------------------

    \37\ The cumulative 3-year averaged visibility improvement from 
new LNB with separated OFA, upgraded wet FGD, and FGC for enhanced 
ESP with FGC (Post-Control Scenario 1) across the three Class I 
areas achieved with LNB and separated OFA, upgraded wet FGD, and 
adding a polishing fabric filter (Post-Control Scenario 2) was 0.095 
delta dv from Unit 1, 0.090 delta dv from Unit 2, 0.089 delta dv 
from Unit 3 and 0.025 delta dv from Unit 4.
---------------------------------------------------------------------------

    Based on its consideration of the five-factors, the State 
determined the current ESPs with FGC are reasonable for BART. The State 
determined that fabric filters were not reasonable based on the high 
cost-effectiveness values. The State determined that the PM BART 
emission limit for Jim Bridger Units 1 through 4 is 0.03 lb/MMBtu.
    We agree with the State's conclusions, and we are proposing approve 
its PM BART determination for Jim Bridger Units 1-4.
vi. PacifiCorp Naughton Units 1-3
    PacifiCorp Naughton is located in Lincoln County, Wyoming. Naughton 
is comprised of three pulverized coal-fired units with a total net 
generating capacity of 700 MW. Naughton Unit 1 generates a nominal 160 
MW and commenced operation in 1963. Naughton Unit 2 generates a nominal 
210 MW and commenced operation in 1968. Naughton Unit 3 generates a 
nominal 330 MW and commenced operation in 1971. All three boilers are 
tangentially fired boilers. The State's BART determinations can be 
found in Chapter 6.5.6 and Appendix A of the SIP. The NOX 
BART analysis for Unit 1 and Unit 2 is discussed in section VIII.A of 
this notice.
Wyoming's NOX BART Determination for Naughton Unit 3
    Naughton Unit 3 is currently controlled with LNBs with OFA with 
permit limits of 0.75 lb/MMBtu (93-hour block) and 0.49 lb/MMBtu 
(annual). The State determined that tuning the existing LNBs, existing 
LNBs with OFA and SNCR, and existing LNBs with OFA and SCR were all 
technically feasible for controlling NOX emissions from Unit 
3. The State did not identify any technically infeasible options.
    Wyoming treated Naughton Unit 3 differently than most other units 
in that it did not assume that Unit 3 would first upgrade the 
combustion controls. The State did not identify any energy or non-air 
quality environmental impacts that would preclude the selection of any 
of the controls evaluated, and there no remaining-useful-life issues 
for this source. A summary of the State's NOX BART analyses 
for Unit 3 is provided in Table 19 below. Baseline NOX 
emissions are 6,563 tpy for Unit 3 based on the unit heat input rate of 
3,700 MMBtu/hr and 7,884 hours of operation per year.

                                            Table 19--Summary of Wyoming's Naughton Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                Emission rate                                                                             (delta dv for
                                              (lb/MMBtu)  (30-      Emission                          Average cost    Incremental cost  the maximum 98th
             Control technology                  day rolling    reduction  (tpy)  Annualized costs    effectiveness     effectiveness      percentile
                                                  average)                                               ($/ton)                            impact at
                                                                                                                                             Bridger
                                                                                                                                        Wilderness Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tuning Existing LNBs........................              0.37             1,167           $95,130               $82                --              0.25
Existing LNBs with OFA and SNCR.............              0.30             2,188         1,916,039               876            $1,783              0.46
Existing LNB with OFA and SCR...............              0.07             5,542        15,682,702             2,830             4,105              1.00
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on its consideration of the five-factors, the State 
determined that the existing LNBs with OFA plus SCR were NOX 
BART for Unit 3. The State determined the NOX BART emission 
limit for Naughton Unit 3 is 0.07 lb/MMBtu (30-day rolling average).
EPA's NOX BART Determination for Naughton Unit 3
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. Baseline NOX emissions are 4,544 tpy for Unit 3 
based on the actual annual average for the years 2001-2003. A summary 
of the EPA's NOX BART analysis and the visibility impacts is 
provided in Tables 20 and 21 below.

                                              Table 20--Summary of EPA's Naughton Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Visibility
                                                                                                                                           improvement
                                                                                                                                          (delta dv for
                                                Emission rate       Emission                          Average cost    Incremental cost  the maximum 98th
             Control technology                  (lb/MMBtu)     reduction  (tpy)  Annualized costs    effectiveness     effectiveness      percentile
                                              (annual average)                                           ($/ton)                         impact at Wind
                                                                                                                                          Cave National
                                                                                                                                              Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Existing LNBs with OFA......................              0.33               442          $106,393              $240                --              0.17
Existing LNBs with OFA and SNCR.............              0.23             1,673         3,896,839             2,329            $3,081              0.70
Existing LNBs with OFA and SCR..............              0.05             3,922        12,718,731             3,243             3,922              1.51
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Naughton Unit 3 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 21 
below.

[[Page 34760]]

                             Table 21--Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                            impact)-existing  impact)-existing  impact)-existing
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Fitzpatrick...............................................              0.09              0.33              0.74
N. Absaroka...............................................              0.04              0.16              0.36
Washakie..................................................              0.06              0.23              0.51
Teton.....................................................              0.08              0.30              0.66
Grand Teton...............................................              0.09              0.33              0.73
Yellowstone...............................................              0.07              0.26              0.57
----------------------------------------------------------------------------------------------------------------

    As stated above, the State determined that NOX BART for 
Naughton Unit 3 was existing LNBs plus OFA with SCR with an emission 
limit of 0.07 lb/MMBtu (30-day rolling average). We find this 
determination reasonable given that the average cost effectiveness is 
reasonable at $3,243/ton with significant visibility improvement at the 
most impacted Class I area of 1.51 dv, as well as improvements ranging 
from 0.36 dv to 0.74 dv at six other Class I areas.
    We agree with the State's conclusions, and we are proposing to 
approve its NOX BART determination for Naughton Unit 3.
    We are also asking if interested parties have additional 
information regarding the possible conversion of Naughton Unit 3 from a 
coal fired unit to a natural gas fired unit as part of a better-than-
BART demonstration to the proposed requirement for the installation of 
combustion controls and SCR.\38\ PacifiCorp has indicated that 
converting the unit to natural gas would reduce NOX 
emissions to 0.10 lb/MMbtu, and nearly eliminate all SO2 
emissions. If PacifiCorp proceeds with their planned conversion to 
natural gas, we seek comment on whether the interested parties think 
the Agency should consider the conversion of Naughton Unit 3 to natural 
gas as a BART control technology option that could be finalized as 
either a FIP, or a SIP (if the Agency were to receive a SIP revision 
from the State) instead of BART as proposed, with associated changes to 
the proposed regulatory text as necessary.
---------------------------------------------------------------------------

    \38\ At PacifiCorp's request, on December 11, 2013, EPA Region 8 
met with PacifiCorp. PacifiCorp discussed the option of Naughton 
Unit 3 being converted to natural gas and stated that they were 
working on the analysis. In subsequent conversations with the State, 
EPA learned that PacifiCorp had submitted its analysis to the State, 
which the State then provided to EPA. We have included this 
information in the docket (see document titled 2/19/2013 Email from 
Cole Anderson, Wyoming DEQ, to Laurel Dygowski, EPA Region 8).
---------------------------------------------------------------------------

PM BART Determination
    Naughton Units 1 and 2 are currently controlled for PM with ESPs 
and FGC. The current permit limit for Units 1 and 2 is 0.04 lb/MMBtu. 
Unit 3 is required by permit to install fabric filters for both Units 
by 2014 with a permit limit of 0.015 lb/MMBtu. The State determined 
that fabric filters were technically feasible for controlling PM 
emissions for Units 1 and 2. The State did not identify any technically 
infeasible controls. The State determined that a fabric filter on Unit 
3 represents the most stringent PM control technology and that 0.015 
lb/MMBtu represents the most stringent emission limit. Consistent with 
the BART Guidelines, the State did not provide a full five-factor 
analysis because the State determined BART to be the most stringent 
control technology and limit.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's PM BART analyses for Units 1 and 
2 is provided in Table 22 below. Baseline emissions for Unit 1 are 409 
tpy and 605 tpy for Unit 2 based on unit heat input rate of 1,850 
MMBtu/hr and 7,884 hours of operation per year.

                                       Table 22--Summary of PacifiCorp Naughton Unit 1 and Unit 2 PM BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Emission rate
                                                                     Control      (lb/MMBtu)  (30-      Emission                          Average cost
                      Control technology                         efficiency  (%)     day rolling    reduction  (tpy)  Annualized costs    effectiveness
                                                                                      average)                                               ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fabric Filter--Unit 1.........................................              73.2             0.015               299        $3,436,594           $11,494
Fabric Filter--Unit 2.........................................              76.6             0.015               464         4,101,705             8,848
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State did not provide visibility improvement modeling for 
fabric filters, but EPA is proposing to conclude this is reasonable 
based on the high cost-effectiveness values of fabric filters at each 
of the units, which are higher than EPA or other state have considered 
reasonable for PM BART.
    Based on its consideration of the five-factors, the State 
determined that the existing ESPs with FGC were reasonable for PM BART 
for Units 1 and 2. The State determined that fabric filters were not 
reasonable based on the high cost-effectiveness values. The State 
determined that the PM BART emission limit for Naughton Unit 1 and Unit 
2 is 0.04 lb/MMBtu. The State determined the PM BART emission limit for 
Naughton Unit 3 is 0.015 lb/MMBtu.
    We agree with the State's conclusions, and we are proposing to 
approve its PM BART determination for Naughton Units 1, 2, and 3.
vii. PacifiCorp Wyodak--Unit 1
Background
    PacifiCorp Wyodak power plant is located in Campbell County, 
Wyoming. Wyodak is comprised of one coal-fired

[[Page 34761]]

boiler, Unit 1, burning pulverized sub-bituminous Powder River Basin 
coal for a total net generating capacity of a nominal 335MW. Wyodak's 
boiler commenced service in 1978. The State's BART determination can be 
found in Chapter 6.5.7 and Appendix A of the SIP. The NOX 
BART analysis for Wyodak Unit 1 is discussed in Section VII.A of this 
notice.
Wyodak Unit 1 PM BART Determination
    Wyodak Unit 1 is currently controlled with fabric filters with an 
emission limit of 0.015 lb/MMBtu (30-day rolling average). The State 
determined that fabric filters on Wyodak Unit 1 represent the most 
stringent PM control technology and that 0.015 lb/MMBtu represents the 
most stringent emission limit. Consistent with the BART Guidelines, the 
State did not provide a full five-factor analysis because the State 
determined BART to be the most stringent control technology and limit. 
The State determined the PM BART emission limit for Wyodak Unit 1 is 
0.015 lb/MMBtu.
    We agree with the State's conclusions, and we are proposing to 
approve its PM BART determination for Wyodak Unit 1.

D. Reasonable Progress Requirements

    In order to establish RPGs for it Class I areas, and to determine 
the controls needed for the LTS, Wyoming followed the process 
established in the RHR. Wyoming identified sources (other than BART 
sources) and source categories in Wyoming that are major contributors 
to visibility impairment and considered whether these sources should be 
controlled based on a consideration of the factors identified in the 
CAA and EPA's regulations (see CAA 169A(g)(1) and 40 CFR 
51.308(d)(1)(i)(A)). Wyoming then identified the anticipated visibility 
improvement in 2018 in all its Class I areas using the WRAP Community 
Multi-Scale Air Quality (CMAQ) modeling results.
1. Visibility Impairing Pollutants and Sources
    In order to determine the significant sources contributing to haze 
in Wyoming's Class I areas, Wyoming relied upon two source 
apportionment analysis techniques developed by the WRAP. The first 
technique was regional modeling using the Comprehensive Air Quality 
Model (CAMx) and the PM Source Apportionment Technology (PSAT) tool, 
used for the attribution for sulfate and nitrate sources only. The 
second technique was the Weighted Emissions Potential (WEP) tool, used 
for attribution of sources of OC, EC, PM2.5, and 
PM10. The WEP tool is based on emissions and residence time, 
not dispersion modeling, and looks at all sources throughout the 
modeling domain.
    PSAT uses the CAMx air quality model to simulate nitrate-sulfate-
ammonia chemistry and apply this chemistry to a system of tracers or 
``tags'' to track the chemical transformations, transport, and removal 
of NOX and SO2. These two pollutants are 
important because they tend to originate from anthropogenic sources. 
Therefore, the results from this analysis can be useful in determining 
contributing sources that may be controllable, both in-state and in 
neighboring states.
    WEP is a screening tool that helps to identify source regions that 
have the potential to contribute to haze formation at specific Class I 
areas. Unlike PSAT, this method does not account for chemistry or 
deposition. The WEP combines emissions inventories, wind patterns, and 
residence times of air masses over each area where emissions occur, to 
estimate the percent contribution of different pollutants. Like PSAT, 
the WEP tool compares baseline values (2000-2004) to 2018 values, to 
show the improvement expected by 2018 for OC, EC, PM2.5, and 
PM10. More information on the WRAP modeling methodologies is 
available in the document Technical Support Document for Technical 
Products Prepared by the Western Regional Air Partnership (WRAP) in 
Support of Western Regional Haze Plans in the Supporting and Related 
Materials section of the docket. Table 23 shows Wyoming's contribution 
to extinction at its own Class I areas.
---------------------------------------------------------------------------

    \39\ Extinction and species contribution to total particulate 
extinction taken from IMPROVE data (http://vista.cira.colostate.edu/dev/web/AnnualSummaryDev/Composition.aspx). IMPROVE data for NOABI 
based on available data for 2002-2004. Contribution of sulfate and 
nitrate based on PSAT; OC, EC, PM2.5, and PM10 
contribution based on WEP as taken from the WRAP TSS (http://vista.cira.colostate.edu/tss/).

               Table 23--Wyoming Sources Extinction Contribution 2000-2004 for 20% Worst Days \39\
----------------------------------------------------------------------------------------------------------------
                                                                                   Species
                                                                               contribution to  Wyoming  sources
             Class I area                 Pollutant  species      Extinction        total        contribution to
                                                                    (Mm-1)       particulate         species
                                                                               extinction (%)    extinction (%)
----------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand       Sulfate.................         4.3              16.7               5.9
 Teton National Park, Teton
 Wilderness.
                                       Nitrate.................         1.8               7.0               4.7
                                       OC......................        13.5              52.4              72.6
                                       EC......................         2.5               9.7              66.8
                                       Fine PM.................         1.0               3.9              24.0
                                       Coarse PM...............         2.6              10.1              20.0
                                       Sea Salt................         0.02              0.08  ................
North Absaroka Wilderness, Washakie    Sulfate.................         4.9              20.7               5.6
 Wilderness.
                                       Nitrate.................         1.6               6.8               8.2
                                       OC......................        11.6              48.9              44.6
                                       EC......................         1.9               8.0              39.5
                                       Fine PM.................         0.8               3.4              14.0
                                       Coarse PM...............         2.9              12.2              12.1
                                       Sea Salt................  ...........              0.04  ................
Bridger Wilderness, Fitzpatrick        Sulfate.................         5.0              22.2              15.4
 Wilderness.
                                       Nitrate.................         1.4               6.2              19.4
                                       OC......................        10.5              46.6              58.5
                                       EC......................         2.0               8.9              51.0
                                       Fine PM.................         1.1               4.9              30.3
                                       Coarse PM...............         2.5              11.1              27.4

[[Page 34762]]

 
                                       Sea Salt................         0.04              0.2   ................
----------------------------------------------------------------------------------------------------------------

    Table 24 shows influences from sources both inside and outside of 
Wyoming per the PSAT modeling for 2018. As indicated, the outside 
domain (OD) region is the highest contributor to sulfate and nitrate at 
all Wyoming Class I areas. The outside domain region represents the 
concentration of pollutants at the boundaries of the modeling domain. 
Depending on meteorology and the type of pollutant (particularly 
sulfate), these emissions can be transported great distances from 
regions such as Canada, Mexico, and the Pacific Ocean. Wyoming is the 
second highest contributor of particulate sulfate and nitrate at 
Bridger and Fitzpatrick Wilderness areas, but is a lesser contributor 
at the other Class I areas.
---------------------------------------------------------------------------

    \40\ OD denotes Outside Domain; ID denotes Idaho, MT denotes 
Montana, CAN denotes Canada, UT denotes Utah, WA denotes Washington, 
WY denotes Wyoming, CA denotes California, and OR denotes Oregon.

                                           Table 24--PSAT Source Region Apportionment for 20% Worst Days \40\
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
Class I area                                     .................................          2018 Sulfate PSAT
                                                                       2018 Nitrate PSAT
--------------------------------------------------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand Teton National  Region...........................     OD     ID     WY    CAN     OR     OD     ID     WA     UT     OR
 Park, Teton Wilderness.
                                                --------------------------------------------------------------------------------------------------------
                                                 % Contribution...................   46.5    8.1    5.8    5.4    4.6   31.3   28.2    9.4    7.4    7.0
                                                --------------------------------------------------------------------------------------------------------
North Absaroka Wilderness, Washakie Wilderness.  Region...........................     OD    CAN     MT     ID     WY     OD     ID     MT    CAN     WY
                                                --------------------------------------------------------------------------------------------------------
                                                 % Contribution...................   50.1   12.5    6.5    5.7    5.5   30.7   16.7   14.8   11.5    8.2
                                                --------------------------------------------------------------------------------------------------------
Bridger Wilderness, Fitzpatrick Wilderness.....  Region...........................     OD     WY     ID     UT    CAN     OD     WY     UT     ID     CA
                                                --------------------------------------------------------------------------------------------------------
                                                 % Contribution...................   31.1   15.3    7.6    5.9    5.1   21.8   19.3   15.6   10.6    6.8
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Table 25 shows the WEP contribution by source category for EC, OC, 
PM2.5, and PM10.

                          Table 25--WEP Source Category Contribution for 20% Worst Days
----------------------------------------------------------------------------------------------------------------
                                                                                   Anthropogenic   Natural fires
          Class I area                 Point           Area           Mobile           fires       and biogenic
----------------------------------------------------------------------------------------------------------------
                                                       OC
----------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand           0.408           3.892           1.636           8.303          85.764
 Teton National Park, Teton
 Wilderness.....................
North Absaroka Wilderness,                 0.661           9.449           2.844          11.881          75.159
 Washakie Wilderness............
Bridger Wilderness, Fitzpatrick            0.984           7.552           3.28            7.644          80.543
 Wilderness.....................
----------------------------------------------------------------------------------------------------------------
                                                       EC
----------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand           0.243           2.628          13.659           5.51           77.958
 Teton National Park, Teton
 Wilderness.....................
North Absaroka Wilderness,                 0.386           5.755          23.253           7.054          63.55
 Washakie Wilderness............
Bridger Wilderness, Fitzpatrick            0.54            4.509          25.65            4.105          65.195
 Wilderness.....................
----------------------------------------------------------------------------------------------------------------
                                                      PM2.5
----------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand           5.565          70.463           0.086           5.469          18.411
 Teton National Park, Teton
 Wilderness.....................
North Absaroka Wilderness,                 3.491          86.311           0.171           3.334           6.691
 Washakie Wilderness............
Bridger Wilderness, Fitzpatrick           16.311          69.195           0.081           3.618          10.785
 Wilderness.....................
----------------------------------------------------------------------------------------------------------------

[[Page 34763]]

 
                                                      PM10
----------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand           2.655          83.939           0.363           0.717          12.316
 Teton National Park, Teton
 Wilderness.....................
North Absaroka Wilderness,                 2.066          93.197           0.213           0.313           4.206
 Washakie Wilderness............
Bridger Wilderness, Fitzpatrick            6.775          84.157           0.477           0.353           8.23
 Wilderness.....................
----------------------------------------------------------------------------------------------------------------

    Table 25 shows that EC, OC, PM2.5 and PM10 
emissions come mainly from sources such as natural fire, windblown 
dust, and road dust. To select the sources that would undergo the 
required four-factor analysis, Wyoming looked at State emission 
inventory data in conjunction with the source apportionment information 
discussed above (a summary of the State's emission inventory can be 
found in section VI.E.1 of this notice). After evaluating this 
information, the State determined that stationary source emissions of 
NOX and SO2 were reasonable to evaluate for 
purposes of reasonable progress controls. The State also determined 
that emissions of NOX from oil and gas development should be 
analyzed for purposes of reasonable progress. Since emissions of OC, 
EC, PM2.5, and PM10 come from mainly 
uncontrollable sources, the State determined it was reasonable to not 
evaluate these pollutants for reasonable progress controls. The State 
submitted a January 12, 2011, SIP that addresses sources of 
SO2.\41\ Thus, the State evaluated emissions of the 
remaining pollutant, NOX, for reasonable progress in this 
SIP.
---------------------------------------------------------------------------

    \41\ The State submitted a January 12, 2011 SIP submittal to 
address the requirements under 40 CFR 51.309, with the exception of 
the 40 CFR 51.309(g) requirements addressed in this SIP action.
---------------------------------------------------------------------------

2. Four-Factor Analysis
    In determining the measures necessary to make reasonable progress, 
States must take into account the following four factors and 
demonstrate how they were taken into consideration in selecting 
reasonable progress goals for each Class I area:
     Costs of Compliance;
     Time Necessary for Compliance;
     Energy and Non-air Quality Environmental Impacts of 
Compliance; and
     Remaining Useful Life of any Potentially Affected Sources.

CAA Sec.  169A(g)(1) and 40 CFR 308(d)(1)(i)(A).
    The State performed a four factor analysis for each of the 
reasonable progress sources pursuant to 40 CFR 51.308(d)(1)(i)(A).
a. Stationary Sources
    The State used a reasonable progress screening methodology termed 
``Q/d'' to determine which stationary sources would be candidates for 
controls under reasonable progress. Q/d is a calculated ratio where Q 
represents (in this case) the NOX emission rate in tpy of 
the source divided by the distance in kilometers of the point source 
from the nearest Class I area, denoted by ``d.'' The State used the 
maximum permitted emission rate for each source to determine the tpy of 
NOX in the Q/d calculation. The State determined that a Q/d 
value of 10 is reasonable for determining which sources the State 
should consider for reasonable progress controls, since this value 
yielded sources of concern similar in magnitude to sources subject-to-
BART.
    The State determined there were three units with a Q/d of greater 
than 10 that are not already being controlled under BART and the State 
completed a reasonable progress analysis for each of the sources. The 
sources are PacifiCorp Dave Johnston Unit 1 and Unit 2 and Mountain 
Cement Company Laramie Plant kiln. Dave Johnston Units 1 and 2 are 
addressed as part of our FIP in section VII.B of this notice. In 
addition, as previously mentioned, the State considered reasonable 
controls on oil and gas development sources.
b. Summary of Reasonable Progress Determinations and Limits
    For the subject-to-reasonable progress sources, the State provided 
analyses that took into consideration the four factors as required by 
section 169A(g)(1) of the CAA and 40 CFR 51.308(d)(1)(i)(A). For the 
stationary sources, the State relied on the analysis found in 
Supplementary Information for Four-Factor Analyses for Selected 
Individual Facilities in Wyoming, May 6, 2009, Revised Draft Report 
Prepared by EC/R Incorporated. For oil and gas sources, the State 
relied on the analysis found in Supplementary Information for Four 
Factor Analyses by WRAP States, May 4, 2009 (Corrected 4/20/10) Revised 
Draft Report Prepared by EC/R Incorporated (for a complete copy of the 
reports see Chapter 7 of the State's TSD). The analyses considered 
EPA's BART Guidelines as relevant to their reasonable progress 
evaluations, as well as EPA's Guidance for Setting Reasonable Progress 
Goals Under the Regional Haze Program.
    In this action, EPA is proposing to approve the reasonable progress 
NOX determinations submitted by the State for oil and gas 
sources and for Mountain Cement Company Laramie Plant kiln. EPA is 
proposing to disapprove the State's reasonable progress determinations 
and proposing to issue a reasonable progress determination 
NOX FIP for PacifiCorp Dave Johnston Unit 1 and Unit 2. As 
with the BART EGUs, EPA is providing revised cost analyses and 
visibility improvement modeling for PacifiCorp Dave Johnston Unit 1 and 
2. We are also providing the original reasonable progress analyses EPA 
relied on in its June 4, 2012 proposed rulemaking. EPA's rationale for 
disapproving the State's reasonable progress determination for these 
units, as well as EPA's reasonable progress FIP determination, can be 
found in section VIII.B of this notice.
    A summary of the reasonable progress analysis and determination for 
each source/source category that we are proposing to approve is 
provided below.
i. Oil and Gas Sources
Background
    Oil and gas exploration and production is occurring in numerous 
areas in Wyoming. The sources associated with oil and gas production 
mainly emit NOX and VOCs; in this context, the State 
considered NOX. Oil and gas production and exploration 
includes operation, maintenance, and servicing of production 
properties, including transportation to and from sites. EC/R evaluated 
reasonable progress control technologies for common sources in the oil 
and gas industry including compressor engines, turbines, process 
heaters, and drilling rig engines. The State's NOX 
reasonable progress determination for oil and gas

[[Page 34764]]

sources can be found in Chapter 7.3.5 of the SIP.
NOX Reasonable Progress Determination
    For compressor engines, potential control options identified by the 
State include air-fuel ratio controls (AFRC), ignition timing retard, 
low-emission combustion (LEC) retrofit, SCR, SNCR, and replacement with 
electric motors. The State evaluated several control technologies for 
drilling rig engines including ignition timing retard, exhaust gas 
recirculation (EGR), SCR, replacement of Tier 2 engines with Tier 4 
engines, and diesel oxidation catalyst. Potential controls for turbines 
identified by the State include water or steam injection, LNBs, SCR, 
and water or steam injection with SCR. NOX emission control 
technologies identified by the State for process heaters include LNBs, 
ultra-low NOX burners (ULNBs), LNBs with flue gas 
recirculation (FGR), SNCR, SCR, and LNBs installed in conjunction with 
SCR.
    NOX emissions vary based on the equipment and fuel 
source. Emissions from individual natural gas-fired turbines at 
production operations can be as high as 877 tpy of NOX, 
while emissions from individual natural gas turbines at exploration 
operations can reach 131 tpy of NOX. Individual gas 
reciprocating engines have comparable NOX emissions with up 
to 700 tpy at production operations and 210 tpy at exploration 
operations. Diesel engine emissions can approach 46 tpy for production 
operations and 10 tpy for exploration operations.
    Table 26 provides a summary of the reasonable progress 
NOX analysis for oil and gas sources. Both the capital and 
annual costs for each technology is dependent on the engine size or on 
the process throughput; therefore, for most of the control technologies 
listed in Table 26, the State has provided cost estimate ranges. The 
lower end of the cost/ton estimates represent the cost per unit for 
larger or higher production units, while the higher end of the cost/ton 
estimates represent the cost per unit for the smaller or lower 
production units. The capital and annual cost figures are expressed in 
terms of the cost per unit of engine size or per unit of process 
throughput.

                       Table 26--Summary of Reasonable Progress NOX Analysis for Oil and Gas Exploration and Production Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Estimated                        Estimated
                                                             control         Pollutant        capital    Annual cost                           Cost
            Source type              Control  technology    efficiency      controlled       cost  ($/     ($/year/          Units         effectiveness
                                                               (%)                             unit)        unit)                             ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Compressor Engines................  AFRC.................        10-40  NOX...............       5.3-42      0.9-6.8  hp................        68-2,500
                                    Ignition timing              15-30  NOX...............          N/A          1-3  hp................        42-1,200
                                     retard.
                                    LEC retrofit.........        80-90  NOX...............      120-820       30-210  hp................       320-2,500
                                    SCR..................           90  NOX...............      100-450       40-270  hp................      870-31,000
                                    SNCR.................        90-99  NOX...............        17-35          3-6  hp................           16-36
                                    Replacement with               100  NOX...............      120-140        38-44  hp................       100-4,700
                                     electric motors.
Drilling Rig Engines and Other      Ignition timing              15-30  NOX...............       16-120        14-66  hp................     1,000-2,200
 Engines.                            retard.
                                    EGR..................           40  NOX...............          100        26-67  hp................       780-2,000
                                    SCR..................        80-95  NOX...............    100-2,000     40-1,200  hp................     3,000-7,700
                                    Replacement of Tier 2           87  NOX...............          125           20  hp................       900-2,400
                                     engines with Tier 4.
Turbines..........................  Water or steam               68-80  NOX...............       4.4-16          2-5  1000 BTU..........       560-3,100
                                     injection.
                                    LNB..................        68-84  NOX...............         8-22      2.7-8.5  1000 BTU..........    2,000-10,000
                                    SCR..................           90  NOX...............        13-34       5.1-13  1000 BTU..........     1,000-6,700
                                    Water or steam               93-96  NOX...............        13-34       5.1-13  1000 BTU..........     1,000-6,700
                                     injection with SCR.
Process Heaters...................  LNB..................           40  NOX...............      3.8-7.6    0.41-0.81  1000 BTU..........     2,100-2,800
                                    ULNB.................        75-85  NOX...............       4.0-13     0.43-1.3  1000 BTU..........    1, 500-2,000
                                    LNB and FGR..........           48  NOX...............           16          1.7  1000 BTU..........           2,600
                                    SNCR.................           60  NOX...............        10-22      1.1-2.4  1000 BTU..........     4,700-5,200
                                    SCR..................        70-90  NOX...............        33-48      3.7-5.6  1000 BTU..........     2,900-6,700
                                    LNB and SCR..........        70-90  NOX...............        37-55        4-6.3  1000 BTU..........     2,900-6,300
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Wyoming states that it would need up to two years to develop the 
necessary regulations to control oil and gas sources.\42\ The State 
estimated that companies would require a year to procure the necessary 
capital to purchase the control equipment. The time required to design, 
fabricate, and install control technologies will vary based on the 
control technology selected and other factors.
---------------------------------------------------------------------------

    \42\ For all reasonable progress sources, the time necessary to 
develop regulations is not a consideration under the time necessary 
for compliance factor. If regulations are needed to implement 
reasonable progress controls, the State must develop them as part of 
the regional haze SIP.
---------------------------------------------------------------------------

    The State determined that no additional controls for oil and gas 
sources were reasonable at this time. The State concluded that 
emissions from large stationary sources processing oil and gas in the 
WRAP region have been well quantified over the years, while smaller 
exploration and production sources that the State is evaluating for 
reasonable progress have not had the same degree of emission inventory 
development. The State points out that understanding the sources and 
volume of emissions at oil and gas production sites is necessary to 
recognizing the impact that these emissions have on visibility.
    To better understand the emissions from stationary and mobile 
equipment

[[Page 34765]]

operated as part of oil and gas field operations, the WRAP has been 
working on developing an emission inventory to more fully characterize 
the oil and gas field operations emissions. The WRAP's development of a 
more comprehensive emission inventory is still in process (as of the 
date of the State's SIP submittal). The State determined it cannot 
complete the evaluation of oil and gas on visibility until the WRAP 
emission inventory study has been completed.
    The State points out that in the case of compressor engines, many 
facilities have already installed control equipment.\43\ For lean burn 
engines, oxidation catalysts are commonly installed, while SNCR with 
AFRC are commonly installed for rich burn engines. The State also 
points out that regulating drill rig engines can be problematic since 
drill rig engines are, for the most part, considered mobile sources and 
emission limits for mobile sources are set by the Federal government 
under section 202 of the CAA.
---------------------------------------------------------------------------

    \43\ Oil and gas sources are regulated by the State as part of 
its minor source BACT requirements in Wyoming Air Quality Standards 
and Regulations Chapter 6, Section 2.
---------------------------------------------------------------------------

    We disagree with the State's reasoning for not adopting reasonable 
progress controls for oil and gas sources. If the State determined that 
additional information was needed to potentially control oil and gas 
sources, the State should have developed the information. While we 
disagree with the State's reasoning for not requiring any controls 
under reasonable progress, we are proposing to approve the State's 
conclusion that no additional NOX controls are warranted for 
this planning period. As shown by the four-factor analyses, the most 
reasonable controls are for compressor engines, which the State already 
controls through its minor source BACT requirements (see above). In 
addition, while the costs of some controls are within the range of 
cost-effectiveness values Wyoming, other states, and we have considered 
as reasonable in the BART context, they are not so low that we are 
prepared to disapprove the State's conclusion in the reasonable 
progress context. Therefore, we are proposing to approve the State's 
reasonable progress determination for oil and gas sources.
ii. Mountain Cement Company Laramie Plant--Kiln
Background
    The Mountain Cement Company Laramie Plant cement kiln is a long dry 
kiln with a capacity of 1,500 tons of clinker per day. Assuming the 
plant runs 365 days of the year, the result is 547,500 tpy of clinker.
NOX Reasonable Progress Determination
    The kiln is currently uncontrolled for NOX emissions. 
The State determined that indirect and direct firing of LNBs, biosolid 
injection, NOxOUT\SM\, CemSTAR\SM\, LoTOxTM, SCR, SNCR 
(using urea), and SNCR (using ammonia) were technically feasible for 
controlling NOX emissions from the kiln. The State did not 
identify any technically infeasible controls.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's NOX reasonable 
progress analyses for the kiln is provided in Table 27 below. Baseline 
NOX emissions for the kiln are 524 tpy based on 2002 actual 
emissions.

               Table 27--Summary of Mountain Cement Company Kiln NOX Reasonable Progress Analysis
----------------------------------------------------------------------------------------------------------------
                                                                                                      Cost
         Control technology                Control            Emission       Annualized costs  effectiveness ($/
                                        efficiency (%)    reduction (tpy)                             ton)
----------------------------------------------------------------------------------------------------------------
LNB (indirect)......................              30-40            157-210           $205,000       $6,568-4,910
LNB (direct)........................                 40                210            449,000             13,853
Biosolid Injection \44\.............                 50                262           -127,000              1,324
NOxOUT \SM\.........................                 35                183            507,000              8,023
CemSTAR \SM\ \45\...................              20-60            105-314            Unknown            Unknown
LoTOxTM \46\........................              80-90            419-472            Unknown            Unknown
SCR.................................                 80                419          7,553,000             82,535
SNCR (urea) \47\....................                 35                183            Unknown              1,223
SNCR (ammonia)......................                 35                183            Unknown              1,223
----------------------------------------------------------------------------------------------------------------
\44\ A negative annual cost is given because cement kilns receive a credit for the biosolids tipping fee paid by
  facilities providing the biosolids to the cement plant. For the purposes of this analysis, the tipping fee is
  $5.00/ton.
\45\ Cost effectiveness figures for the CemStar\SM\ process were not available for dry kilns.
\46\ Cost effectiveness figures for LoTOxTM were not available for dry kilns.
\47\ Capital and annual costs for SNCR have only been evaluated for preheater and precalcnier kilns. Only cost
  effectiveness figures were available for dry kilns.

    The State estimated that it could potentially take seven years to 
install control equipment on the kiln. This estimate includes the two 
years that will be necessary for the State to implement new regulations 
and the one-year Mountain Cement will likely need to obtain the 
necessary capital for the purchase of new emission control technology. 
The State estimates the total time necessary for compliance will vary 
based on the control technology selected. For example, the State 
predicts that one and a half years will be required to design, 
fabricate, and install SCR or SNCR technology, while over two and a 
half years will be required to design, fabricate, and install LoTOx\TM\ 
technology.
    The State determined no controls were reasonable for reasonable 
progress for Mountain Cement Company Laramie Plant kiln. The State 
cited that the four-factor analysis was limited, in that no guidance 
was provided by EPA for identifying significant sources and EPA did not 
establish contribution to visibility impairment thresholds (a potential 
fifth factor for reasonable progress determinations).\48\ The State 
further claims that the State cannot, per Wyoming Statute 35-11-202, 
establish emission control requirements except through State rule or 
regulation. Furthermore, the Wyoming statute requires the State to 
consider the

[[Page 34766]]

character and degree of injury of the emissions involved. In this case, 
the State claims it would need to have visibility modeling that 
assessed the degree of injury caused by the emissions, which the State 
does not have. The State believes it has taken a strong and reasonable 
first step in identifying potential contributors to visibility 
impairment, and that the next step of creating an appropriate rule or 
regulation will be accomplished in the next SIP revision.
---------------------------------------------------------------------------

    \48\ States must consider the four factors as listed above but 
can also take into account other relevant factors for the reasonable 
progress sources identified (see EPA's Guidance for Setting 
Reasonable Progress Goals under the Regional Haze Program, (``EPA's 
Reasonable Progress Guidance''), p. 2-3, July 1, 2007).
---------------------------------------------------------------------------

    We disagree with the State's reasoning for not adopting reasonable 
progress controls for Mountain Cement Company Laramie Plant kiln. If 
the State determined that it needed to adopt a rule or perform modeling 
to adequately assess and, if warranted, require reasonable progress 
controls, the State should have completed these steps before it 
submitted its regional haze SIP. The RHR does not allow for commitments 
to potentially implement strategies at some later date that are 
identified under reasonable progress or for the State to take credit 
for such commitments. Nor does it allow the State to consider the time 
to promulgate regulations as part of the time for compliance.
    While we disagree with the State's reasoning for not requiring any 
controls under reasonable progress, we are proposing to approve the 
State's conclusion that no additional NOX controls are 
warranted for this planning period. While the costs of some controls 
(i.e., biosolid injection and SNCR) are within the range of cost-
effectiveness values that Wyoming, other states, and EPA have 
considered as reasonable in the BART context, the costs are not so low 
that we are prepared to disapprove the State's conclusion in the 
reasonable progress context. In addition, these additional controls 
only afford relatively modest emission reductions.
3. Reasonable Progress Goals
    40 CFR 51.308(d)(1) requires states to ``establish goals'' (in 
deciviews) that provide for reasonable progress towards achieving 
natural visibility conditions for each Class I area of the State. These 
RPGs are interim goals that must provide for incremental visibility 
improvement for the most impaired visibility days, and ensure no 
degradation for the least impaired visibility days. The RPGs for the 
first planning period are goals for the year 2018.
    Wyoming relied on WRAP modeling to establish its RPGs for 2018. The 
primary tool WRAP relied upon for modeling regional haze improvements 
by 2018, and for estimating Wyoming's RPGs, was the CMAQ model. The 
CMAQ model was used to estimate 2018 visibility conditions in Wyoming 
and all western Class I areas, based on application of anticipated 
regional haze strategies in the various states' regional haze plans, 
including assumed controls on BART sources.
    The Regional Modeling Center (RMC) at the University of California 
Riverside conducted the CMAQ modeling under the oversight of the WRAP 
Modeling Forum. The RMC developed air quality modeling inputs including 
annual meteorology and emissions inventories for: (1) A 2002 actual 
emissions base case; (2) a planning case to represent the 2000-2004 
regional haze baseline period using averages for key emissions 
categories; (3) a 2018 base case of projected emissions determined 
using factors known at the end of 2005; and (4) a 2018 reasonable 
progress case to represent anticipated BART controls. All emission 
inventories were spatially and temporally allocated using the Sparse 
Matrix Operator Kernel Emissions (SMOKE) modeling system. Each of these 
inventories underwent a number of revisions throughout the development 
process to arrive at the final versions used in CMAQ modeling.
    The photochemical modeling of regional haze for the WRAP states for 
2002 and 2018 was conducted on the 36-km resolution national regional 
planning organization domain that covered the continental United 
States, portions of Canada and Mexico, and portions of the Atlantic and 
Pacific Oceans along the east and west coasts. The RMC examined the 
model performance of the regional modeling for the areas of interest 
before determining whether the CMAQ model results were suitable for use 
in the regional haze assessment of the LTS and for use in the modeling 
assessment. The 2002 modeling efforts were used to evaluate air 
quality/visibility modeling for a historical episode, in this case, for 
calendar year 2002, to demonstrate the suitability of the modeling 
systems for subsequent planning, sensitivity, and emissions control 
strategy modeling. Model performance evaluation compares output from 
model simulations with ambient air quality data for the same time 
period to determine whether model performance is sufficiently accurate 
to justify using the model to simulate future conditions. Once the RMC 
determined that model performance was acceptable, it used the model to 
determine the 2018 RPGs using the current and future year air quality 
modeling predictions, and compared the RPGs to the uniform rate of 
progress. A more detailed description of the CMAQ modeling performed 
for the WRAP can be found in the Chapter 5 of the State's TSD.
    The State determined that the WRAP 2018 projections represent 
significant visibility improvement and reasonable progress toward 
natural visibility based upon the State's consideration of the factors 
required for BART and reasonable progress. The State adopted the WRAPs 
2018 projections as their RPG for each Class I area. Table 28 shows the 
URP and the 2018 RPGs adopted by the State.

                                                        Table 28--Wyoming's URP and RPGs for 2018
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                20% Worst days                                     20% Best days
                                                    ----------------------------------------------------------------------------------------------------
                                                                                        Reduction
               Wyoming Class I Areas                    2000-2004                       needed to     2018 CMAQ modeling     2000-2004       2018 CMAQ
                                                        Baseline        2018 URP     reach URP goal  projection--State's     Baseline        modeling
                                                       (deciview)      (deciview)         (delta             RPG            (deciview)      projection
                                                                                        deciview)                                           (deciview)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Yellowstone National Park, Grand Teton National                11.8            10.5             0.7               11.2               2.6             2.4
 Park, Teton Wilderness............................
North Absaroka Wilderness, Washakie Wilderness.....            11.5            10.4             0.6               11.0               2.0             2.0
Bridger Wilderness, Fitzpatrick Wilderness.........            11.1            10.0             0.6               10.6               2.1             2.0
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 34767]]

    Table 28 shows that the State's regional haze SIP is providing for 
improvement in visibility for the most-impaired days for the period 
ending in 2018 and allows for no degradation in visibility for the 
least-impaired days.
    Table 28 also shows that Wyoming is not meeting the URP to meet 
natural visibility conditions by 2064. In this case, 40 CFR 
51.308(d)(1)(ii) requires the State to demonstrate, based on the four 
factors in 51.308(d)(1)(i)(A), that the RPGs established in this SIP 
are reasonable for this planning period and that achieving the URP in 
this planning period is not reasonable. In its demonstration, the State 
cited many reasons why meeting the URP was not reasonable, including 
the following. First, emissions from natural sources greatly affect the 
State's ability to meet the 2018 URP. As discussed earlier, WEP data 
shows that emissions of OC, EC, PM2.5, and PM10 
come mainly from natural or non-anthropogenic sources, such as natural 
wildfire and windblown dust. The State has little or no control over 
OC, EC, PM2.5, and PM10 emissions associated with 
natural fire and windblown dust. Second, emissions from sources outside 
the WRAP modeling domain also affect the State's ability to meet the 
2018 URP. Sources outside of the modeling domain are the single largest 
source region contributor to sulfate and nitrate at the State's Class I 
areas. These sources are not under the control of Wyoming or the 
surrounding states.
    Because the State is not meeting the URP, the State is required by 
40 CFR 51.308(d)(1)(ii) to assess the number of years it would take to 
reach natural conditions if visibility improvement continues at the 
current rate of progress. The State has calculated the year and the 
length of time to reach natural visibility as follows: Yellowstone 
National Park, Grand Teton National Park, and Teton Wilderness: 2130 
(126 years); North Absaroka Wilderness and Washakie Wilderness: 2136 
(132 years); and Bridger Wilderness and Fitzpatrick Wilderness: 2165 
(161 years).
    EPA disagrees with the State's assessment that, based on the 
factors in 40 CFR 51.308(d)(1)(i)(a), all reasonable controls were 
implemented by the State for this first planning period of the regional 
haze program. In particular, as discussed in sections VIII.A and 
VIII.B. below, we find unreasonable the State's determination to not 
impose more stringent NOX BART controls on certain sources 
or not to impose any reasonable progress controls at PacifiCorp Dave 
Johnston Units 1 and 2. As a result, EPA is proposing to disapprove the 
State's RPGs, and because we are proposing to disapprove Wyoming's 
RPGs, we are also proposing a FIP to replace them. See discussion in 
section VIII.C below.

E. Long Term Strategy

1. Emission Inventories
    40 CFR 51.308(d)(3)(iii) requires that Wyoming document the 
technical basis, including modeling, monitoring, and emissions 
information, on which it relied to determine its apportionment of 
emission reduction obligations necessary for achieving reasonable 
progress in each mandatory Class I Federal area it affects. Wyoming 
must identify the baseline emissions inventory on which its strategies 
are based. 40 CFR 51.308(d)(3)(iv) requires that Wyoming identify all 
anthropogenic sources of visibility impairment it considered in 
developing its LTS. This includes major and minor stationary sources, 
mobile sources, and area sources.
    In order to meet these requirements, Wyoming relied on the emission 
inventory developed by the WRAP. The State has provided an emission 
inventory for SO2, NOX, VOC, OC, EC, 
PM2.5, PM10, and NH3. The inventory 
provides the baseline year 2002 emissions and provides projections of 
future emissions in 2018 based on expected controls, growth, and other 
factors. The following are the inventory source categories identified 
by the State: point, area, on-road mobile, off-road mobile, 
anthropogenic fire, natural fire, road dust, fugitive dust, area source 
oil and gas, and biogenic emissions. The emission inventories developed 
by the WRAP were calculated using best available data and approved EPA 
methods.\49\ Following is a summary of the emission inventory for each 
pollutant by source.
---------------------------------------------------------------------------

    \49\ The methods WRAP used to develop these emission inventories 
are described in more detail in Technical Support Document for 
Technical Products Prepared by the Western Regional Air Partnership 
(WRAP) in Support of Western Regional Haze Plans in the Supporting 
and Related Materials section of the docket.
---------------------------------------------------------------------------

SO2
    Sulfur dioxide emissions come primarily from coal combustion at 
EGUs, but smaller amounts come from natural gas combustion, mobile 
sources, and wood combustion.

[[Page 34768]]

             Table 29--Wyoming SO2 Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................      119,717       96,809          -19
Area.............................       16,689       23,093           38
On-Road Mobile...................          959           81          -92
Off-Road Mobile..................        5,866           65          -99
Oil & Gas........................          150            3          -98
Road Dust........................            0            0            0
Fugitive Dust....................            0            0            0
Windblown Dust...................            0            0            0
Anthropogenic Fire...............          173          109          -37
Natural Fire.....................        2,286        2,286            0
Biogenic.........................            0            0            0
                                  --------------------------------------
    Total........................      145,840      122,446          -16
------------------------------------------------------------------------

    The State expects a 16% reduction in SO2 emissions by 
2018 due to planned controls on existing sources, even with expected 
growth in generating capacity for the State.
NOX
    NOX emissions in Wyoming come mostly from point sources 
and from on-road and off-road mobile sources.

             Table 30--Wyoming NOX Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................      117,806      110,109           -7
Area.............................       15,192       19,663           29
On-Road Mobile...................       38,535        9,728          -75
Off-Road Mobile..................       76,637       49,677          -35
Oil & Gas........................       14,725       34,142          132
Road Dust........................            0            0            0
Fugitive Dust....................            0            0            0
Windblown Dust...................            0            0            0
Anthropogenic Fire...............          782          484          -38
Natural Fire.....................        8,372        8,372            0
Biogenic.........................       15,925       15,925            0
                                  --------------------------------------
    Total........................      287,974      248,100          -14
------------------------------------------------------------------------

    The State expects NOX emissions to decrease by 14% by 
2018, primarily due to significant reductions in mobile source 
emissions. The State projects that off-road and on-road vehicles 
emissions will decline by more than 55,760 tpy from the baseline 2002 
emissions of 115,172 tpy.
OC
    A wide variety of sources contribute emissions to this pollutant, 
including diesel emissions and combustion byproducts from wood and 
agricultural burning.

              Table 31--Wyoming OC Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................          646          990           53
Area.............................        2,000        1,975           -1
On-Road Mobile...................          304          249          -18
Off-Road Mobile..................          625          411          -34
Oil & Gas........................            0            0            0
Road Dust........................           20           26           30
Fugitive Dust....................           96          133           39
Windblown Dust...................            0            0            0
Anthropogenic Fire...............        1,709          886          -48
Natural Fire.....................       23,793       23,793            0
Biogenic.........................            0            0            0
                                  --------------------------------------
    Total........................       29,193       28,463           -3
------------------------------------------------------------------------

[[Page 34769]]

    OC emissions from all sources are expected to show a 3% decline. 
Natural fire is the largest source contributing to OC emissions. The 
State does not have the ability to predict future emissions from 
natural fires and thus, the State held this category constant in the 
inventory.
EC
    EC is a byproduct of incomplete combustion. EC emissions mainly 
come from mobile sources and natural fires.

              Table 32--Wyoming EC Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................          104          180           73
Area.............................          304          335           10
On-Road Mobile...................          443           86          -81
Off-Road Mobile..................        1,986        1,161          -42
Oil & Gas........................            0            0            0
Road Dust........................            2            2            0
Fugitive Dust....................            7            9           29
Windblown Dust...................            0            0            0
Anthropogenic Fire...............          298          153          -49
Natural Fire.....................        4,922        4,922            0
Biogenic.........................            0            0            0
                                  --------------------------------------
    Total........................        8,066        6,848          -15
------------------------------------------------------------------------

    The State predicts EC emissions to decrease approximately 15% by 
2018. Reductions in manmade emissions of EC are largely due to mobile 
sources emission reductions resulting from new federal emission 
standards for mobile sources, especially for diesel engines.
PM2.5
    PM2.5 emissions come mainly from agricultural and mining 
activities, windblown dust from construction areas, and emissions from 
unpaved and paved roads.

            Table 33--Wyoming PM2.5 Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................       11,375       15,709           38
Area.............................        1,601        1,756           10
On-Road Mobile...................            0            0            0
Off-Road Mobile..................            0            0            0
Oil & Gas........................            0            0            0
Road Dust........................          160          206           29
Fugitive Dust....................        2,082        2,882           38
Windblown Dust...................        5,838        5,838            0
Anthropogenic Fire...............          242          129          -47
Natural Fire.....................        1,535        1,535            0
Biogenic.........................            0            0            0
                                  --------------------------------------
    Total........................       22,833       28,055           23
------------------------------------------------------------------------

    The State predicts emissions of PM2.5 to increase 23% by 
2018. Emission increases are related to population growth and an 
increase in vehicle miles traveled.
PM10
    PM10 emissions come from many of the same sources as 
PM2.5 emissions but other activities like rock crushing and 
processing, material transfer, open pit mining, and unpaved road 
emissions also can be prominent sources.

             Table 34--Wyoming PM10 Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................       24,751       30,619           24
Area.............................          409          653           60
On-Road Mobile...................          171          165           -4
Off-Road Mobile..................            0            0            0
Oil & Gas........................            0            0            0
Road Dust........................        1,125        1,449           29
Fugitive Dust....................       18,030       25,144           39
Windblown Dust...................       52,546       52,546            0
Anthro Fire......................          259          109          -58
Natural Fire.....................        5,369        5,369            0

[[Page 34770]]

 
Biogenic.........................            0            0            0
                                  --------------------------------------
    Total........................      102,660      116,054           13
------------------------------------------------------------------------

    Overall, PM10 emissions are expected to increase by 13%. 
increases in coarse PM emissions are linked to population growth and 
vehicle miles traveled.
NH3
    NH3 emissions come from a variety of sources including 
wastewater treatment facilities, livestock operations, fertilizer 
application, mobile sources, and point sources.

             Table 35--Wyoming NH3 Emissions--2002 and 2018
------------------------------------------------------------------------
                                     Baseline                  Percent
         Source category               2002     Future 2018     change
------------------------------------------------------------------------
Point............................          685        1,398          104
Area.............................       29,776       29,901            0
On-Road Mobile...................          538          724           35
Off-Road Mobile..................           41           57           39
Oil & Gas........................            0            0            0
Road Dust........................            0            0            0
Fugitive Dust....................            0            0            0
Windblown Dust...................            0            0            0
Anthropogenic Fire...............          218          119          -45
Natural Fire.....................        1,775        1,775            0
Biogenic.........................            0            0            0
                                  --------------------------------------
    Total........................       33,033       33,974            3
------------------------------------------------------------------------

    NH3 emissions are expected to increase by 3% by 2018. 
Increases in NH3 emissions are linked to population growth 
and increased vehicular traffic.
2. Consultation and Emissions Reductions for Other States' Class I 
Areas
    40 CFR 51.308(d)(3)(i) requires that Wyoming consult with another 
state if its emissions are reasonably anticipated to contribute to 
visibility impairment at that state's Class I area(s), and that Wyoming 
consult with other states if those other states' emissions are 
reasonably anticipated to contribute to visibility impairment at its 
Class I areas. The State participated in regional planning, 
coordination, and consultation with other states in developing emission 
management strategies through the WRAP. Through the WRAP consultation 
process, Wyoming has reviewed and analyzed contributions from other 
states that reasonably may cause or contribute to visibility impairment 
in Wyoming's Class I areas and analyzed Wyoming's impact on other 
states' Class I areas.
    40 CFR 51.308(d)(3)(ii) requires that if Wyoming emissions cause or 
contribute to impairment in another state's Class I area, Wyoming must 
demonstrate that it has included in its regional haze SIP all measures 
necessary to obtain its share of the emission reductions needed to meet 
the RPG for that Class I area. Section 51.308(d)(3)(ii) also requires 
that, since Wyoming participated in a regional planning process, it 
must ensure it has included all measures needed to achieve its 
apportionment of emission reduction obligations agreed upon through 
that process. As we state in the RHR, Wyoming's commitments to 
participate in WRAP bind it to secure emission reductions agreed to as 
a result of that process.
    The State determined it did potentially impact Class I areas in 
South Dakota, Colorado, Utah, Idaho, Montana, and North Dakota (see 
Table 8.1.2.1-1 in the SIP). Wyoming accepted and incorporated the 
WRAP-developed visibility modeling into its regional haze SIP and the 
SIP includes the controls assumed in the modeling. Wyoming has 
satisfied the RHR requirements for consultation and included controls 
in the SIP sufficient to address the relevant requirements related to 
impacts on Class I areas in other states.
    We are proposing to find that the State has met the requirements 
for consultation under 40 CFR 51.308(d)(3)(i) and 40 CFR 
51.308(d)(3)(ii).
3. Mandatory Long-Term Strategy Requirements
    40 CFR 51.308(d)(3)(v) requires that Wyoming, at a minimum, 
consider certain factors in developing its LTS. These are: (a) Emission 
reductions due to ongoing air pollution control programs, including 
measures to address RAVI; (b) measures to mitigate the impacts of 
construction activities; (c) emissions limitations and schedules for 
compliance to achieve the reasonable progress goals; (d) source 
retirement and replacement schedules; (e) smoke management techniques 
for agricultural and forestry management purposes including plans that 
currently exist within the state for these purposes; (f) enforceability 
of emissions limitations and control measures; and (g) the anticipated 
net effect on visibility due to projected changes in point, area, and 
mobile source emissions over the period addressed by the LTS.
a. Reductions Due to Ongoing Air Pollution Programs
    In addition to its BART and reasonable progress determinations, the 
State's LTS contains other reductions due to ongoing air pollution 
programs. The State's LTS contains numerous ongoing air pollution 
programs, including: (1) New Source Review Program, which is a permit 
program for

[[Page 34771]]

the construction of new sources and the modification of existing 
sources; (2) Prevention of Significant Deterioration Program, which 
protects visibility from proposed major stationary sources or major 
modifications to existing facilities; and (3) New Source Performance 
Standards, which the State incorporates by reference on an annual 
basis. For a complete listing of ongoing air pollution programs in 
Wyoming, see Chapter 8.2.1 of the SIP.
b. Measures To Mitigate the Impacts of Construction Activities
    Chapter 3 of the Wyoming Air Quality Standards and Regulations 
(WAQSR) establishes limits on the quantity or concentration of 
emissions of air pollutants from numerous sources, including 
construction activities. Specifically, WAQSR Chapter 3, Section 2(f), 
prescribes measures to ensure the control of fugitive dust emissions 
during construction or demolition activities. WAQSR Chapter 3, Section 
2(f) requires any person engaged in clearing or leveling of land, 
earthmoving, excavation, or movement of trucks or construction 
equipment over access haul roads or cleared land to take steps to 
minimize fugitive dust from such activities. Such control measures may 
include frequent watering and/or chemical stabilization. EPA approved 
WAQSR Chapter 3 into the SIP on July 28, 2004 (69 FR 44965).
c. Smoke Management
    WAQSR Chapter 10 establishes restrictions and requirements on 
different types of burning in Wyoming. WAQSR Chapter 10, Section 2 
regulates open burning, including refuse burning, open burning of trade 
wastes, open burning at salvage operations, open burning for 
firefighting training, and small vegetative material open burning (not 
exceeding 0.25 tons per day of PM). WAQSR Chapter 10, Section 3 
regulates emissions from wood waste burners. EPA approved WAQSR Chapter 
10, Section 2 and 3 into the SIP on July 28, 2004 (69 FR 44965). WAQSR 
Chapter 10, Section 4 was adopted by the State and submitted to EPA to 
meet the requirements for programs related to fire under 40 CFR 
51.309(d)(6). Chapter 10, Section 4 seeks to minimize the impacts from 
private and prescribed burning on visibility in Class I areas and 
potentially affected populations. EPA is proposing approval of Chapter 
10, Section 4 in a separate action.
d. Emission Limitations and Schedules for Compliance
    Chapter 6.5 of the State's SIP contains the emission limitations 
and schedules for compliance for BART sources. Chapter 6.5 of the SIP 
requires the BART sources to install and demonstrate compliance with 
the State's BART determination as expeditiously as practicable, but no 
later than five years after EPA approval of the SIP. For some sources 
where controls have already been installed, the State specifies an 
earlier compliance deadline in Chapter 6.5 of the SIP. In addition, 
Chapter 8.3.3 of the SIP contains the emission limits and compliance 
schedule for LTS controls on Jim Bridger Units 1-4.
e. Source Retirement and Replacement Schedules
    The State is not currently aware of any specific scheduled 
shutdowns, retirements in upcoming years, or replacement schedules, 
such as planned installation of new control equipment to meet other 
regulations. If such actions occur, the State will factor them into 
upcoming reviews.
f. Enforceability of Wyoming's Measures
    As discussed in section VII.D of this notice, EPA is proposing to 
disapprove the State's SIP because it contains inadequate monitoring, 
recordkeeping, and reporting requirements, and we are proposing a FIP 
to address the enforceability of BART and reasonable progress controls.
g. Anticipated Net Effect on Visibility Due to Projected Changes
    The anticipated net effect on visibility due to projected changes 
in point, area, and mobile source emissions during this planning period 
is addressed in section VI.D.3 of this notice.
4. Our Conclusions on Wyoming's Long-Term Strategy
    We propose to partially approve and partially disapprove Wyoming's 
LTS. Because we are proposing to disapprove the NOX BART 
determinations for PacifiCorp Dave Johnston Unit 3 and Unit 4, 
PacifiCorp Naughton Units 1 and 2, PacifiCorp Wyodak Unit 1, and Basin 
Electric Laramie River Units 1, 2, and 3, we are also proposing to 
disapprove the corresponding emission limits and compliance schedules 
that Wyoming relied on as part of its LTS. Because we are proposing to 
disapprove the reasonable progress determination for PacifiCorp Dave 
Johnston Units 1 and 2, we are also proposing to disapprove the LTS 
because it does not include appropriate NOX reasonable 
progress emission limits and compliance schedules for Dave Johnston 
Units 1 and 2. We are also proposing to disapprove the State's LTS 
because it does not contain the necessary monitoring, recordkeeping, 
and reporting requirements to make the BART and reasonable progress 
limits practically enforceable. Except for these elements, the State's 
LTS satisfies the requirements of 40 CFR 51.308(d)(3), and we are 
proposing to approve it.

F. Coordination of RAVI and Regional Haze Rule Requirements

    Per 40 CFR 51.306(c), the State must provide for review and 
revision of a coordinated LTS for addressing RAVI and regional haze, 
and the State must submit the first such coordinated LTS with its first 
regional haze SIP. The State did not provide for the coordination of 
their RAVI and regional haze LTS. We are proposing to disapprove the 
State's SIP as not meeting the requirements of 40 CFR 51.306(c). We are 
proposing a FIP as explained in section VIII.F of this notice to meet 
the coordination requirements of 40 CFR 51.306(c).

G. Monitoring Strategy and Other Implementation Plan Requirements

    40 CFR 51.308(d)(4) requires that the SIP contain a monitoring 
strategy for measuring, characterizing, and reporting regional haze 
visibility impairment that is representative of all mandatory Class I 
Federal areas within the state. This monitoring strategy must be 
coordinated with the monitoring strategy required in 40 CFR 51.305 for 
RAVI. As 40 CFR 51.308(d)(4) notes, compliance with this requirement 
may be met through participation in the IMPROVE network. 40 CFR 
51.308(d)(4)(i) further requires the establishment of any additional 
monitoring sites or equipment needed to assess whether the RPGs for all 
mandatory Class I Federal areas within the state are being achieved.
    Consistent with EPA's monitoring regulations for RAVI and regional 
haze, Wyoming states in Chapter 9 of the regional haze SIP that it will 
rely on the IMPROVE network for compliance purposes, in addition to any 
additional visibility impairment monitoring that may be needed in the 
future.
    Section 51.308(d)(4)(ii) requires that states establish procedures 
by which monitoring data and other information are used in determining 
the contribution of emissions from within Wyoming to regional haze 
visibility impairment at mandatory Class I Federal areas both within 
and outside the state. The IMPROVE monitoring program is national in 
scope, and other states have similar monitoring and data reporting 
procedures, ensuring a consistent and robust monitoring data collection 
system. As 40 CFR 51.308(d)(4) indicates, Wyoming's participation in

[[Page 34772]]

the IMPROVE program constitutes compliance with this requirement.
    40 CFR 51.308(d)(4)(iv) requires that the SIP provide for the 
reporting of all visibility monitoring data to the Administrator, at 
least annually, for each mandatory Class I Federal area in the state. 
To the extent possible, Wyoming should report visibility monitoring 
data electronically. 40 CFR 51.308(d)(4)(vi) also requires that the SIP 
provide for other elements, including reporting, recordkeeping, and 
other measures, necessary to assess and report on visibility. We 
propose that Wyoming's participation in the IMPROVE network ensures 
that the monitoring data is reported at least annually and is easily 
accessible; therefore, such participation complies with this 
requirement. IMPROVE data are centrally compiled and made available to 
EPA, states and the public via various electronic formats and Web sites 
including IMPROVE (http://vista.cira.colostate.edu/improve/) and VIEWS 
(http://vista.cira.colostate.edu/views/).
    40 CFR 51.308(d)(4)(v) requires that Wyoming maintain a statewide 
inventory of emissions of pollutants that are reasonably anticipated to 
cause or contribute to visibility impairment in any mandatory Class I 
Federal area. The inventory must include emissions for a baseline year, 
emissions for the most recent year for which data are available, and 
estimates of future projected emissions. The State must also include a 
commitment to update the inventory periodically. The State's emission 
inventory is discussed in section VI.F.1 of this notice. Wyoming states 
in Chapter 9 of the SIP that it intends to update the Wyoming statewide 
emissions inventories periodically and review periodic emissions 
information from other states and future emissions projections. We 
propose that this satisfies the requirement.
    40 CFR 51.308(d)(4)(vi) requires that states provide for any 
additional reporting, recordkeeping, and measures necessary to evaluate 
and report on visibility. The State of Wyoming, in accordance with 
provisions of 40 CFR 51.308(d)(4)(vi), will track data related to 
regional haze for sources for which the State has regulatory authority, 
and will depend on the IMPROVE program and RPO sponsored collection and 
analysis efforts for monitoring and emissions inventory data, 
respectively. To ensure the availability of data and analyses to report 
on visibility conditions and progress toward Class I area visibility 
goals, the State of Wyoming will collaborate with members of a RPO to 
ensure the continued operation of the IMPROVE program and RPO sponsored 
technical support analysis tools and systems.
    We propose to find that the State's SIP satisfies the requirements 
of 40 CFR 51.308(d)(4).

H. Consultation With FLMs

    Although the FLMs are very active in participating in the RPOs, the 
RHR grants the FLMs a special role in the review of the regional haze 
SIPs, summarized in section V.H above. Under 40 CFR 51.308(i)(2), 
states are obligated to provide the FLMs with an opportunity for 
consultation, in person, and at least 60 days prior to holding a public 
hearing on the regional haze SIP. The State provided an opportunity for 
FLM consultation, in person and at least 60 days prior to holding any 
public hearing on the SIP. As required by 40 CFR Section 51.308(i)(3), 
the State has included FLM comments and State responses in Chapter 11 
of the Wyoming TSD.
    40 CFR 51.308(i)(3) requires that states provide in its regional 
haze SIP a description of how it addressed any comments provided by the 
FLMs. The FLMs formally commented on the Wyoming proposed SIP in 
November and December of 2010. The FLM comments provided support for 
the modeling approach used by the State in the BART determinations and 
complimented the State on thorough BART, reasonable progress, and area 
source analysis. The FLMs also recommended the State reevaluate costs 
and emission limits for some of the BART and reasonable progress 
sources. Chapter 11 of the State's TSD provides detailed information on 
the State's response to FLM comments.
    Lastly, 40 CFR 51.308(i)(4) specifies the regional haze SIP must 
provide procedures for continuing consultation between a state and FLMs 
on the implementation of the visibility protection program required by 
40 CFR 51.308. This includes development and review of implementation 
plan revisions and five-year progress reports and the implementation of 
other programs having the potential to contribute to impairment of 
visibility in mandatory Class I Federal areas. Pursuant to Chapter 11.2 
of the SIP, the State will provide the FLMs an opportunity to review 
and comment on SIP revisions, the five-year progress reports, and other 
developing programs that may contribute to Class I visibility 
impairment.
    We are proposing that the State's SIP satisfies the requirements of 
40 CFR 51.308(i).

I. Periodic SIP Revisions and 5-Year Progress Reports

    40 CFR 51.308(f) requires a state to revise and submit its regional 
haze SIP to EPA by July 31, 2018, and every ten years thereafter. 
Pursuant to Chapter 10 of the SIP, the State will provide this 
revision. In accordance with the requirements listed in 40 CFR 
51.308(g), the State will submit a report on reasonable progress to EPA 
every five years following the initial submittal of the SIP. That 
report will be in the form of an implementation plan revision. The 
State's report will evaluate the progress made towards the RPGs for 
each mandatory Class I area located within the State and in each 
mandatory Class I area located outside the State, which have been 
identified as being affected by emissions from the State. The State 
will also evaluate the monitoring strategy adequacy in assessing RPGs.
    Based on the findings of the five-year progress report, 40 CFR 
51.308(h) requires a state to make a determination of adequacy of the 
current implementation plan. The State must take one or more of the 
actions listed in 40 CFR 51. 308(h)(1) through (4) that are applicable 
at the same time as the state submits a five-year progress report. 
Chapter 12 of the SIP requires the State to make an adequacy 
determination of the current SIP pursuant to 40 CFR 51.308(h)(1) 
through (4) at the same time a five-year progress report is due.
    We propose to find the State's SIP satisfies the requirements of 40 
CFR 51.308(f)-(h).

VIII. Federal Implementation Plan

    EPA is proposing a FIP to address the deficiencies indentified in 
our proposed partial disapproval of Wyoming's regional haze SIP. In 
lieu of our proposed FIP, or a portion thereof, we will propose 
approval of a SIP revision as expeditiously as practicable if the State 
submits such a revision and the revision matches the terms of our 
proposed FIP. We will also review and take action on any regional haze 
SIP submitted by the state to determine whether such SIP is approvable, 
regardless of whether or not its terms match those of the FIP. We 
encourage the State to submit a SIP revision to replace the FIP, either 
before or after our final action.

A. Disapproval of the State's NOX BART Determinations and 
Federal Implementation Plan for NOX BART Determinations and 
Limits

    As noted above, the State provided five-factor analyses that 
considered all factors, but we find that its

[[Page 34773]]

consideration of the costs of compliance and visibility improvement was 
inconsistent with regulatory and statutory requirements. In 
disapproving specific State BART determinations in our proposed 
rulemaking notice on June 4, 2012, we based our analysis on information 
provided by the State in their BART analyses, with the exception of 
visibility improvement modeling, and thus accepted the cost information 
provided by the State. In this proposed rulemaking, in addition to the 
other BART information in the State SIP submittal, we are basing our 
proposed BART determinations on cost analyses and visibility 
improvement modeling developed by EPA, as explained in section VII.C of 
this notice. EPA is proposing to disapprove the State's NOX 
BART determinations, and we are proposing to issue a BART FIP, for the 
following units: PacifiCorp Dave Johnston Unit 3 and Unit 4, PacifiCorp 
Naughton Unit 1 and Unit 2, PacifiCorp Wyodak Unit 1, and Basin 
Electric Laramie River Units 1, 2, and 3. EPA's rationale for 
disapproving the State's BART determinations for these units, as well 
as EPA's BART FIP determinations and emission limits, are discussed 
below.
    We are also asking if interested parties have additional 
information or comments regarding the BART factors and EPA's proposed 
determinations, for example our weighing of average costs, incremental 
costs, visibility improvement, and timing of installation of such 
controls, and in light of such information, whether the interested 
parties think the Agency should consider another BART control 
technology option that could be finalized either instead of, or in 
conjunction with, BART as proposed. The Agency is also asking if 
interested parties have additional information or comments on the 
proposed timing of compliance when the challenge of coordinating the 
work our proposed SIP and FIP will require is considered.
    The Agency will take the comments and testimony received, as well 
as any further SIP revisions submitted by the State, into consideration 
in our final promulgation. Supplemental information received may lead 
the Agency to adopt final SIP and/or FIP regulations that reflect a 
different BART control technology option, or impact other proposed 
regulatory provisions, which differ from this proposal.
1. Disapproval of the State's Basin Electric Laramie River Units 1-3 
NOX BART Determination and FIP to Address NOX 
BART
Wyoming's NOX BART Determination
    During the 2001-2003 baseline, Basin Electric Laramie River Units 
1-3 were all controlled with LNBs with a permit limit of 0.5 lbs/MMBtu 
(3-hour rolling average). The State determined that new LNBs, OFA, new 
LNBs and OFA, new SNCR/SCR hybrid \50\, new LNBs and OFA with SNCR, and 
SCR were technically feasible for reducing NOX emissions at 
Units 1-3. The State determined that natural gas re-burn was 
technically infeasible. The State did not identify any energy or non-
air quality environmental impacts that would preclude the selection of 
any of the controls evaluated, and there are no remaining-useful-life 
issues for this source. A summary of the State's NOX BART 
analysis is provided in Tables 36-38 below. As discussed above, the 
visibility improvement modeling results in these tables were developed 
by EPA because Wyoming did not properly follow the BART Guidelines. 
Baseline NOX emissions are 6,320 tpy for Unit 1, 6,285 tpy 
for Unit 2, and 6,448 tpy for Unit 3 based on annual average heat input 
for 2001-2003 and an emission rate of 0.27 lb/MMBtu.
---------------------------------------------------------------------------

    \50\ A hybrid SNCR/SCR system combines the lower costs and 
higher ammonia slip of SNCR with the higher NOx reduction potential 
and lower ammonia slip of SCR. During operation, the SNCR system is 
allowed to inject higher amounts of reagent into the flue gas. The 
increased reagent flow brings about increased NOx reduction, but 
also causes increased ammonia slip which is then consumed by the SCR 
system. The use of the ammonia slip by the SCR system can reduce the 
size of the required SCR catalyst.

                                  Table 36--Summary of Wyoming's Basin Electric Laramie River Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate                                                                    the maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (30-day        reduction         costs       effectiveness       cost         percentile
                                                              rolling          (tpy)                          ($/ton)      effectiveness  impact at Wind
                                                             average)                                                                      Cave National
                                                                                                                                             Park) EPA
                                                                                                                                             analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
OFA.....................................................            0.23             936        $625,000            $668  ..............            0.08
New LNBs................................................            0.23             936       1,360,000           1,453  ..............            0.08
New LNBs with OFA.......................................            0.23             936       1,944,000           2,077  ..............            0.08
SNCR/SCR Hybrid.........................................            0.20           1,639       7,429,000           4,534  ..............  ..............
New LNBs with OFA and SNCR..............................            0.12           3,511       7,365,000           2,098          $2,105            0.32
SCR.....................................................            0.07           4,681      15,787,000           3,372           7,198            0.44
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                  Table 37--Summary of Wyoming's Basin Electric Laramie River Unit 2 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate                                                                    the maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (30-day        reduction         costs       effectiveness       cost         percentile
                                                              rolling          (tpy)                          ($/ton)      effectiveness  impact at Wind
                                                             average)                                                                      Cave National
                                                                                                                                             Park) EPA
                                                                                                                                             analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
OFA.....................................................            0.23             931        $625,000            $671  ..............            0.08

[[Page 34774]]

 
New LNBs................................................            0.23             931      $1,360,000          $1,461  ..............            0.08
New LNBs with OFA.......................................            0.23             931       1,944,000           2,088  ..............            0.08
SNCR/SCR Hybrid.........................................            0.20           1,630       7,429,000           4,559  ..............  ..............
New LNBs with OFA and SNCR..............................            0.12           3,492       7,365,000           2,109          $2,117            0.32
SCR.....................................................            0.07           4,656      15,787,000           3,391           7,242            0.44
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                  Table 38--Summary of Wyoming's Basin Electric Laramie River Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate                                                                    the maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (30-day        reduction         costs       effectiveness       cost         percentile
                                                              rolling          (tpy)                          ($/ton)      effectiveness  impact at Wind
                                                             average)                                                                      Cave National
                                                                                                                                             Park) EPA
                                                                                                                                             analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
OFA.....................................................            0.23             955        $625,000            $654  ..............            0.08
New LNBs................................................            0.23             955       1,360,000           1,424  ..............            0.08
New LNBs with OFA.......................................            0.23             955       1,944,000           2,036  ..............            0.08
SNCR/SCR Hybrid.........................................            0.20           1,672       7,429,000           4,444  ..............  ..............
New LNBs with OFA and SNCR..............................            0.12           3,582       7,365,000           2,056          $2,064            0.33
SCR.....................................................            0.07           4,777      15,787,000           3,305           7,054            0.44
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The State eliminated the SNCR/SCR hybrid from further consideration 
because it has higher cost-effectiveness values and lower control 
efficiency compared to new LNBs plus OFA with SNCR.
    Based on its consideration of the five factors, the State 
determined that new LNBs with OFA were reasonable for NOX 
BART. The State determined that the NOX BART emission limit 
for Laramie River Unit 1 is 0.23 lb/MMBtu (30-day rolling average). The 
State determined that the NOX BART emission limit for 
Laramie River Unit 2 is 0.23 lb/MMBtu (30-day rolling average). The 
State determined that the NOX BART emission limit for 
Laramie River Unit 3 is 0.23 lb/MMBtu (30-day rolling average).
    The State's proposed SIP required additional NOX 
emission reductions for Laramie River under its LTS. Based on the costs 
and visibility improvement for Laramie River Station Units 1, 2, and 3, 
the State proposed installation of two SCRs, or equivalent performing 
emission control systems, at any of the three units. The State proposed 
that the add-on NOX control achieve an emission rate, on an 
individual unit basis, at or below 0.07 lb/MMBtu on a 30-day rolling 
average. The State proposed that the add-on controls be installed and 
operational on one of the Laramie River Station units by December 31, 
2018 and on a second Laramie River Station unit by December 31, 2023.
    On March 8, 2010, Basin Electric Power Cooperative appealed the 
additional controls proposed by the State under its LTS before the 
Wyoming Environmental Quality Council. The State entered into a 
settlement agreement on November 16, 2010 with Basin Electric Power 
Cooperative (a copy of the settlement agreement is included in the 
State's revised NOX BART Analysis for Laramie River dated 
January 3, 2011). As part of the settlement agreement, the State agreed 
to remove the requirement for Basin Electric to install additional 
controls under the LTS. In return, Basin Electric agreed to additional 
NOX emissions reductions under BART. Under the settlement 
agreement, Basin Electric agreed to a NOX emission limit of 
0.21 lb/MMBtu (30-day rolling average) on all three units. Basin 
Electric also agreed to a NOX emission limit for Unit 1 and 
Unit 2 of 4,780 tpy and a NOX emission limit for Unit 3 of 
4,914 tpy, effectively capping emissions from all three units at 12,773 
tpy. In the SIP adopted by the State, the State determined the emission 
limits in the settlement agreement were BART for Basin Electric Laramie 
River Units 1, 2, and 3.
EPA's Basin Electric Laramie River Units 1-3 NOX BART 
Determination and FIP for NOX BART
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. However, EPA disagrees with the State's baseline 
NOX emissions estimates, as listed above, because the State 
based its estimate on annual average heat input for 2001-2003 at an 
emission rate of 0.07 lb/MMBtu and not actual annual averages. EPA's 
revised baseline NOX emissions are 6,051 tpy for Unit 1, 
6,293 tpy for Unit 2, and 6,375 tpy for Unit 3 based on the actual 
annual average for the years 2001-2003. A summary of the EPA's 
NOX BART analysis and the visibility impacts is provided in 
Tables 39-44 below.

[[Page 34775]]

                                            Table 39--Summary of EPA's Laramie River Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                           Emission rate                                                                   (delta dv for
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental     the maximum
                   Control technology                         (annual        reduction         costs       effectiveness       cost            98th
                                                             average)          (tpy)                          ($/ton)      effectiveness    percentile
                                                                                                                                             impact at
                                                                                                                                             Badlands)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.19           1,556      $2,268,806          $1,458  ..............            0.29
New LNBs with OFA and SNCR..............................            0.15           2,445       5,880,822           2,395          $4,018            0.44
New LNBs with OFA and SCR...............................            0.05           4,880      18,146,629           3,718           5,057            0.79
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Laramie River Unit 1 also impacts other Class I areas. The 
visibility improvement modeled by EPA at other Class I areas is shown 
in Table 40 below.

                  Table 40--Laramie River Unit 1: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Wind Cave.................................................              0.20              0.30              0.64
Rawah.....................................................              0.10              0.16              0.32
Rocky Mountain............................................              0.12              0.19              0.37
----------------------------------------------------------------------------------------------------------------

                                            Table 41--Summary of EPA's Laramie River Unit 2 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                           Emission rate                                                                   (delta dv for
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental     the maximum
                   Control technology                         (annual        reduction         costs       effectiveness       cost            98th
                                                             average)          (tpy)                          ($/ton)      effectiveness    percentile
                                                                                                                                             impact at
                                                                                                                                             Badlands)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.19            1823      $2,268,806          $1,244  ..............            0.30
New LNBs with OFA and SNCR..............................            0.15           2,717       5,884,257           2,166          $4,044            0.42
New LNBs with OFA and SCR...............................            0.05           5,129      20,017,988           3,903           5,860            0.73
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Laramie River Unit 2 also impacts other Class I areas. The 
visibility improvement modeled by EPA at other Class I areas is shown 
in Table 42 below.

                  Table 42--Laramie River Unit 2: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Wind Cave.................................................              0.24              0.36              0.66
Rawah.....................................................              0.10              0.16              0.29
Rocky Mountain............................................              0.13              0.19              0.35
----------------------------------------------------------------------------------------------------------------

[[Page 34776]]

                                            Table 43--Summary of EPA's Laramie River Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                           Emission rate                                                                   (delta dv for
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental     the maximum
                   Control technology                         (annual        reduction         costs       effectiveness       cost            98th
                                                             average)          (tpy)                          ($/ton)      effectiveness    percentile
                                                                                                                                             impact at
                                                                                                                                             Badlands)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.19            1789      $2,268,806          $1,268  ..............            0.22
New LNBs with OFA and SNCR..............................            0.15           2,706       5,933,791           2,192          $3,996            0.33
New LNBs with OFA and SCR...............................            0.05           5,181      18,597,027           3,589           5,117            0.67
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Laramie River Unit 3 also impacts other Class I areas. The 
visibility improvement modeled by EPA at other Class I areas is shown 
in Table 44 below.

                  Table 44--Laramie River Unit 3: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Wind Cave.................................................              0.20              0.31              0.60
Rawah.....................................................              0.10              0.15              0.29
Rocky Mountain............................................              0.12              0.18              0.34
----------------------------------------------------------------------------------------------------------------

    As noted above, under the settlement agreement terms incorporated 
into the SIP, Basin Electric agreed to a NOX emission limit 
of 0.21 lb/MMBtu (30-day rolling average) on all three units, and thus 
eliminated other control options. We propose to find that Wyoming did 
not properly follow the requirements of the BART Guidelines in 
determining NOX BART for these units.
    Furthermore, as discussed in detail above, because Wyoming relied 
on visibility modeling methodologies that are inconsistent with the 
statutory and regulatory requirements, we do not consider Wyoming's 
analyses of visibility improvement for the NOX BART to be 
reasonable for the Laramie units. We propose to find that Wyoming's 
analyses for these units are inconsistent with the statutory and 
regulatory requirement that ``the degree of improvement in visibility 
which may reasonably be anticipated to result from the use of such 
technology.''
    Therefore, EPA does not agree with the State's conclusion that a 
limit of 0.21 lb/MMBtu is consistent with the BART Guidelines and 
reasonable for BART for Laramie River Units 1, 2, and 3, which can be 
achieved with the installation and operation of new LNBs with OFA. 
Specifically, we propose to find that in negotiating the emission 
limit, Wyoming did not properly or reasonably ``take into consideration 
the costs of compliance.'' Thus, the State's BART analyses for Basin 
Electric Laramie River Units 1, 2, and 3 do not meet the requirements 
of the regional haze regulation, and we are proposing to disapprove 
those analyses and the State's NOX BART determination. We 
are proposing a FIP for NOX BART to fill the gap left by our 
disapproval, as explained below.
    Our analysis follows our BART Guidelines. Because the Basin 
Electric Laramie River Units 1, 2, and 3 are similar, we are proposing 
a single BART analysis and determination that applies to each unit. 
With the exception of the NOX emission limits, the 
visibility improvement analyses, and the cost-effectiveness analyses, 
EPA is proposing to find that the Wyoming regional haze NOX 
BART analyses for Units 1, 2 and 3, fulfills all the relevant 
requirements of CAA Section 169A and the RHR. As discussed above in 
section VII.C.3.b., Wyoming's visibility improvement analyses for these 
units is inconsistent with the requirements found in the CAA and BART 
Guidelines. Furthermore, we are not relying on the State's costs due to 
the reasons described in section VII.C.3.a above.
    In addition, the cost-effectiveness for new LNBs with OFA and SCR 
ranges from approximately $3,600/ton to $3,900/ton with significant 
visibility improvement at the most impacted Class I area of 0.79 dv for 
Unit 1, 0.73 dv for Unit 2, and 0.67 dv for Unit 3. SCR provides 
significant visibility improvement at other impacted Class I areas, 
with cumulative visibility improvements of 2.12 dv for Unit 1, 1.97 dv 
for Unit 2, and 2.29 dv for Unit 3. When considering the cost 
effectiveness and visibility improvement of new LNBs plus OFA and SCR, 
it is within the range of what EPA has found reasonable for BART in 
other SIP and FIP actions. We also propose to find that the incremental 
cost-effectiveness does not preclude the selection of new LNBs with OFA 
and SCR.
    EPA's NOX BART analyses and the visibility impacts for 
Units 1, 2 and 3 is summarized in Tables 39-44 above and detailed 
information can be found in the docket.\51\ We propose to find that at 
an emission limit of 0.07 lb/MMBtu (30-day rolling average), which can 
be achieved by the installation of new LNBs with OFA plus SCR, is 
reasonable and consistent with the CAA and BART Guideline requirements 
for NOX BART for Basin Electric Laramie River Units 1, 2, 
and 3. Consequently, we are proposing that the FIP NOX BART 
emission limit for Basin Electric Laramie River Unit 1, Unit 2, and 
Unit

[[Page 34777]]

3 is 0.07 lb/MMBtu (30-day rolling average).
---------------------------------------------------------------------------

    \51\ Detailed supporting information for our cost and visibility 
improvement analyses can be found in the Docket (see Staudt memos 
and EPA BART and RP Modeling for Wyoming, respectively).
---------------------------------------------------------------------------

    We propose that Basin Electric meet our proposed emission limit at 
Laramie River Units 1, 2, and 3, as expeditiously as practicable, but 
no later than five years after EPA finalizes action on our proposed 
FIP. This is consistent with the requirements of 40 CFR 51.308(e)(iv).
    We are also asking if interested parties have additional 
information regarding the BART factors and EPA's proposed 
determination, for example our weighing of average costs, incremental 
costs, visibility improvement, and timing of installation of such 
controls, and in light of such information, whether the interested 
parties think the Agency should consider another BART control 
technology option that could be finalized either instead of, or in 
conjunction with, BART as proposed. The Agency will take the comments 
and testimony received, as well as any further SIP revisions submitted 
by the State, into consideration in our final promulgation. 
Supplemental information received may lead the Agency to adopt final 
SIP and/or FIP regulations that reflect a different BART control 
technology option, or impact other proposed regulatory provisions, 
which differ from this proposal.
2. Disapproval of the State's PacifiCorp Dave Johnston Unit 3 and Unit 
4 NOX BART Determinations and FIP To Address NOX 
BART
Wyoming's NOX BART Determination for Dave Johnston Unit 3
    During the baseline period of 2001-2003, Dave Johnston Unit 3 was 
uncontrolled for NOX and had emission limits of 0.75 lb/
MMbtu (3-hour rolling) and 0.59 lb/MMbtu (annual). The State determined 
LNBs with advanced OFA, LNBs with advanced OFA and SNCR, and LNBs with 
advanced OFA and SCR were technically feasible for controlling 
NOX emissions from Unit 3. The State did not identify any 
technically infeasible controls.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. Baseline NOX emissions are 5,814 tpy for Unit 3 
based on unit heat input rate of 2,500 MMBtu/hr and 7,884 hours of 
operation. A summary of the State's NOX BART analysis and 
the visibility impacts is provided in Table 45 below. As discussed 
above, the visibility improvement modeling results in these tables were 
developed by EPA because Wyoming did not properly follow the BART 
Guidelines.

                                          Table 45--Summary of Wyoming's Dave Johnston Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                              (delta
                                                                                                                                           deciview for
                                                           Emission rate     Emission                      Average cost     Incremental     the maximum
                   Control technology                     (lb/MMBtu) (30-    reduction      Annualized     effectiveness       cost            98th
                                                            day rolling        (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                             Park) EPA
                                                                                                                                             analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNB with advanced OFA...................................            0.28           2,723      $1,764,775            $648  ..............            0.77
LNB with advanced OFA and SNCR..........................            0.19           3,717       2,679,192             721            $920            0.94
LNB with advanced OFA and SCR...........................            0.07           5,041      16,347,519           3,243          10,234            1.16
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on its consideration of the five factors, the State 
determined LNBs with OFA were reasonable for NOX BART. The 
State determined the cost of compliance (capital costs and annual 
operating and maintenance costs) were significantly higher for the 
addition of SCR. The State determined that the NOX BART 
emission limit for Unit 3 is 0.28 lb/MMBtu (30-day rolling average).
EPA's Conclusions on Dave Johnston Unit 3 NOX BART 
Determination and Proposed FIP for NOX BART
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. We disagree with the State's estimate of baseline 
NOX emissions (5,814 tpy) because it is based on a unit heat 
input rate of 2,500 MMBtu/hr and 7,884 hours of operation rather than 
an average of actual annual emissions. EPA finds that baseline 
NOX emissions are 4,913 tpy for Unit 3 based on the actual 
annual average for the years 2001-2003. A summary of the EPA's 
NOX BART analysis and the visibility impacts is provided in 
Tables 46 and 47 below.

                                            Table 46--Summary of EPA's Dave Johnston Unit 3 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate     Emission                      Average cost     Incremental     the maximum
                   Control technology                       (lb/MMBtu)       reduction      Annualized     effectiveness       cost            98th
                                                              (annual          (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                               Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNBs with OFA...........................................            0.22           2,837      $1,699,807            $599  ..............            0.64
LNBs with OFA and SNCR..................................            0.16           3,356       3,545,435           1,057          $3,555            0.76
LNBs with OFA and SCR...................................            0.05           4,433      11,262,188           2,540           7,163            1.00
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Dave Johnston Unit 3 also impacts other Class I areas. The 
visibility improvement modeled by EPA at other Class I areas is shown 
in Table 47 below.

[[Page 34778]]

              Table 47--Dave Johnston Unit 3: Visibility Improvement Modeled at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                            impact) - LNBs +  impact) - LNBs +  impact) - LNBs +
                                                                   OFA            OFA/SNCR           OFA/SCR
----------------------------------------------------------------------------------------------------------------
Badlands..................................................              0.44              0.52              0.67
Mt. Zirkel................................................              0.21              0.25              0.33
Rawah.....................................................              0.24              0.29              0.38
Rocky Mountain............................................              0.34              0.41              0.54
----------------------------------------------------------------------------------------------------------------

    EPA does not agree with the State's conclusion that a limit of 0.28 
lb/MMBtu, which can be achieved with the installation and operation of 
LNBs with OFA, is reasonable for NOX BART for Dave Johnston 
Unit 3. We propose to find that Wyoming did not properly follow the 
requirements of the BART Guidelines in determining NOX BART 
for this unit. Specifically, we propose to find that Wyoming did not 
properly or reasonably conduct certain requirements of the BART 
analysis.
    As discussed in detail above, because Wyoming relied on visibility 
modeling methodologies that are inconsistent with the statutory and 
regulatory requirements, we do not consider Wyoming's analysis of 
visibility improvement for the NOX BART to be reasonable for 
Dave Johnston Unit 3. We propose to find that Wyoming's analysis for 
this Unit is inconsistent with the statutory and regulatory requirement 
that ``the degree of improvement in visibility which may reasonably be 
anticipated to result from the use of such technology.''
    Also, we are not relying on the State's costs due to reasons stated 
in section VII.C.3.a. We propose to find that Wyoming did not properly 
or reasonably ``take into consideration the costs of compliance.'' 
Thus, the State's BART analysis for Dave Johnson Unit 3 does not meet 
the requirements of the CAA and the RHR, and we are proposing to 
disapprove the analysis and the State's NOX BART 
determination. We are proposing a FIP for NOX BART to fill 
the gap left by our disapproval, as explained below.
    Our analysis follows our BART Guidelines. With the exception of the 
NOX emission limits, the visibility improvement analyses, 
and the cost analyses, EPA is proposing to find that the Wyoming 
regional haze NOX BART analysis for Dave Johnson Units 3 
fulfills all the relevant requirements of CAA Section 169A and the 
Regional Haze Rule. As discussed above, Wyoming's visibility 
improvement analyses for these units is inconsistent with the 
requirements found in the BART Guidelines.
    EPA's NOX BART analysis and the visibility impacts for 
Dave Johnson Units 3 are summarized in Tables 46-47 above and detailed 
information can be found in the docket.\52\ The cost-effectiveness for 
LNB with OFA and SCR at this unit is $2,540, with visibility 
improvement at the most impacted Class I area of 1.00 dv. SCR provides 
significant visibility improvement at other impacted Class I areas, 
with cumulative visibility improvements of 2.92 dv. We do not find that 
the incremental cost-effectiveness for LNBs with OFA and SCR precludes 
the selection of this technology for BART. The cost-effectiveness and 
visibility improvement are within the range that Wyoming in its SIP and 
EPA in other SIP and FIP actions have considered reasonable in the BART 
context.
---------------------------------------------------------------------------

    \52\ Detailed supporting information for our cost and visibility 
improvement analyses can be found in the Docket (see Staudt memos 
and EPA BART and RP Modeling for Wyoming, respectively).
---------------------------------------------------------------------------

    Based on our examination of the cost estimates and the predicted 
visibility improvement (along with a consideration of the other BART 
factors), we propose to find that LNBs with OFA plus SCR at an emission 
limit of 0.07 lb/MMBtu (30-day rolling average) is reasonable and 
consistent with the CAA and BART Guideline requirements for 
NOX BART for Dave Johnston Unit 3. We are proposing that the 
FIP NOX BART emission limit for PacifiCorp Dave Johnston 
Unit 3 is 0.07 lb/MMBtu (30-day rolling average).
    We propose that PacifiCorp meet our proposed emission limit at Dave 
Johnston Unit, as expeditiously as practicable, but no later than five 
years after EPA finalizes action on our proposed FIP, consistent with 
the requirements of 40 CFR 51.308(e)(iv).
    We are also asking if interested parties have additional 
information regarding the BART factors and EPA's proposed 
determination, for example our weighing of average costs, incremental 
costs, visibility improvement, and timing of installation of such 
controls, and in light of such information, whether the interested 
parties think the Agency should consider another BART control 
technology option that could be finalized either instead of, or in 
conjunction with, BART as proposed. The Agency will take the comments 
and testimony received, as well as any further SIP revisions submitted 
by the State, into consideration in our final promulgation. 
Supplemental information received may lead the Agency to adopt final 
SIP and/or FIP regulations that reflect a different BART control 
technology option, or impact other proposed regulatory provisions, 
which differ from this proposal.
Wyoming's NOX BART Determination for Dave Johnston Unit 4
    Unit 4 is currently controlled with LNBs that were placed in 
operation in 1976. The State determined new LNBs with advanced OFA, new 
LNBs with advanced OFA and SNCR, and new LNBs with advanced OFA and SCR 
were technically feasible for controlling NOX emissions for 
Unit 4. The State did not identify any technically infeasible controls.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. Baseline NOX emissions are 8,566 tpy for Unit 4 
based on unit heat input rate of 2,500 MMBtu/hr and 7,884 hours of 
operation. A summary of the State's NOX BART analysis and 
the visibility impacts is provided in Table 48 below. As discussed 
above, the visibility improvement modeling results in these tables were 
developed by EPA because Wyoming did not properly follow the BART 
Guidelines.

[[Page 34779]]

                                          Table 48--Summary of Wyoming's Dave Johnston Unit 4 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                              (delta
                                                           Emission rate                                                                   deciview for
                                                            (lb/MMBtu)       Emission                      Average cost     Incremental     the maximum
                   Control technology                         (30-day        reduction      Annualized     effectiveness       cost            98th
                                                              rolling          (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                             Park) EPA
                                                                                                                                             analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNB with advanced OFA...............................            0.15           6,142        $841,527            $137  ..............            0.71
New LNB with advanced OFA and SNCR......................            0.12           6,626       2,141,786             323          $2,686            0.80
New LNB with advanced OFA and SCR.......................            0.07           7,435      16,430,528           2,210          17,662            0.97
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on its consideration of the five factors, the State 
determined new LNBs with advanced OFA was reasonable for NOX 
BART for Dave Johnston Unit 4. The State determined the NOX 
BART emission limit for Unit 4 is 0.15 lb/MMBtu (30-day rolling 
average).
EPA's Conclusions on Dave Johnston Unit 4 NOX BART 
Determination and FIP for NOX BART
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. We disagree with the State's estimate of baseline 
NOX emissions (8,566 tpy) because it is based on a unit heat 
input rate of 2,500 MMBtu/hr and 7,884 hours of operation rather than 
an average of actual annual emissions. EPA finds that baseline 
NOX emissions are 5,070 tpy for Unit 4 based on the actual 
annual average for the years 2001-2003. A summary of the EPA's 
NOX BART analysis and the visibility impacts is provided in 
Tables 49 and 50 below.

                                            Table 49--Summary of EPA's Dave Johnston Unit 4 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate     Emission                      Average cost     Incremental     the maximum
                   Control technology                       (lb/MMBtu)       reduction      Annualized     effectiveness       cost            98th
                                                              (annual          (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                               Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.14           3,114        $767,342            $246  ..............            0.84
New LNBs with OFA and SNCR..............................            0.11           3,505       2,592,288             740          $4,665            0.95
New LNBs with OFA and SCR...............................            0.05           4,377      13,021,894           2,975          11,951             1.2
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Dave Johnston Unit 4 also impacts other Class I areas. The 
visibility improvement EPA modeled at other Class I areas is shown in 
Table 50 below.

              Table 50--Dave Johnston Unit 4: Visibility Improvement Modeled at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                              impact) - new     impact) - new     impact) - new
                                                               LNBs + OFA      LNBs + OFA/SNCR   LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Badlands..................................................              0.54              0.57              0.73
Mt. Zirkel................................................              0.28              0.32              0.37
Rawah.....................................................              0.29              0.32              0.39
Rocky Mountain............................................              0.45              0.51              0.63
----------------------------------------------------------------------------------------------------------------

    EPA does not agree with the State's conclusion that a limit of 0.15 
lb/MMBtu, which can be achieved with the installation and operation on 
new LNBs with OFA, is reasonable for NOX BART for Dave 
Johnston Unit 4. We propose to find that Wyoming did not properly 
follow the requirements of the BART Guidelines in determining 
NOX BART for this unit. Specifically, we propose to find 
that Wyoming did not properly or reasonably conduct certain 
requirements of the BART analysis.
    As discussed in detail above, because Wyoming relied on visibility 
modeling methodologies that are inconsistent with the statutory and 
regulatory requirements, we do not consider Wyoming's analysis of 
visibility improvement for the NOX BART to be

[[Page 34780]]

reasonable for Dave Johnston Unit 4. We propose to find that Wyoming's 
analysis for this Unit is inconsistent with the statutory and 
regulatory requirement that ``the degree of improvement in visibility 
which may reasonably be anticipated to result from the use of such 
technology.''
    Also, we are not relying on the State's costs due to reasons stated 
in section VII.C.3.b. We propose to find that Wyoming did not properly 
or reasonably ``take into consideration the costs of compliance.'' 
Thus, the State's BART analysis for Dave Johnson Unit 4 does not meet 
the requirements of the regional haze regulation, and we are proposing 
to disapprove the analysis and the State's NOX BART 
determination. We are proposing a FIP for NOX BART to fill 
the gap left by our disapproval, as explained below.
    Our analysis follows our BART Guidelines. With the exception of the 
NOX emission limits, the visibility improvement analyses, 
and the cost-effectiveness analyses, EPA is proposing to find that the 
Wyoming RH BART analysis of NOX for Dave Johnson Units 4 
fulfills all the relevant requirements of CAA Section 169A and the RHR. 
As discussed above, Wyoming's visibility improvement analyses for these 
units are inconsistent with the requirements found in the BART 
Guidelines.
    EPA's NOX BART analysis and the visibility impacts for 
Dave Johnson Unit 4 are summarized in Tables 49-50 above and detailed 
information can be found in the docket.\53\ Additionally, the cost 
effectiveness and visibility improvement are within the range that 
Wyoming in its SIP and EPA in other SIP and FIP actions have considered 
reasonable and consistent with the BART Guidelines.
---------------------------------------------------------------------------

    \53\ Detailed supporting information for our cost and visibility 
improvement analyses can be found in the Docket (see Staudt memos 
and EPA BART and RP Modeling for Wyoming, respectively).
---------------------------------------------------------------------------

    Based on our examination of the cost estimates and the predicted 
visibility improvement (along with a consideration of the other BART 
factors), we propose to find that new LNBs with OFA plus SNCR at an 
emission limit of 0.12 lb/MMBtu (30-day rolling average) is reasonable 
and consistent with the CAA and BART Guideline requirements for 
NOX BART for Dave Johnston Unit 4. We are proposing that the 
FIP NOX BART emission limit for PacifiCorp Dave Johnston 
Unit 4 is 0.12 lb/MMBtu (30-day rolling average).
    We propose to eliminate the higher performing control option (i.e., 
new LNBs with advanced OFA plus SCR) because, although the average cost 
effectiveness and visibility improvement for SCR are within the range 
EPA has found reasonable in other SIP or FIP actions, we find that the 
incremental cost of SCR at $11,951/ton is high enough so that it 
precludes the selection of SCR.
    We propose that PacifiCorp meet our proposed emission limit at Dave 
Johnston Unit 4, as expeditiously as practicable, but no later than 
five years after EPA finalizes action on our proposed FIP. This is 
consistent with the requirements of 40 CFR 51.308(e)(iv).
    We are also asking if interested parties have additional 
information regarding the BART factors and EPA's proposed 
determination, for example our weighing of average costs, incremental 
costs, visibility improvement, and timing of installation of such 
controls, and in light of such information, whether the interested 
parties think the Agency should consider another BART control 
technology option that could be finalized either instead of, or in 
conjunction with, BART as proposed. The Agency will take the comments 
and testimony received, as well as any further SIP revisions submitted 
by the State, into consideration in our final promulgation. 
Supplemental information received may lead the Agency to adopt final 
SIP and/or FIP regulations that reflect a different BART control 
technology option, or impact other proposed regulatory provisions, 
which differ from this proposal.
3. Proposal in the Alternative for PacifiCorp Jim Bridger Units 1 and 2 
NOX BART
    As noted above, EPA is seeking comment on a proposal (``first 
proposed approach'') to approve the regional haze plan submitted by the 
State for Jim Bridger Unit 1 and Unit 2. EPA also is seeking comment on 
another alternative approach (``second proposed approach'') that would 
determine that BART for Units 1 and 2 at Jim Bridger power plant is 
SCR, and would establish corresponding NOX emission limits 
for these units that would have to be achieved within five years of our 
final action. This would have the effect of accelerating the 
installation of the SCR controls at these units that the State and 
source owner (PacifiCorp) had proposed to install later (in the 2021-
2022 time-period). The State determined that BART for these units is 
LNB plus OFA, and selected the 2021-2022 time-period for SCR-based 
emission limits as a reasonable progress measure. The timeframe was 
based on the large number of actions PacifiCorp is undertaking (or 
helping to finance) at a large number of EGUs in Wyoming, Utah, 
Colorado, and Arizona that it owns and operates or co-owns.
    Under our second proposed approach, EPA would propose that it does 
not agree with the State's conclusion that a limit of 0.26 lb/MMBtu is 
reasonable for BART for Jim Bridger Units 1 and 2, which can be 
achieved with the installation and operation on LNBs with OFA. In 
particular, the cost-effectiveness values that EPA calculated for LNBs 
with OFA and SCR at Unit 1 is $2,393 with a 0.96 deciview visibility 
improvement at the most impacted Class I area. The cost-effectiveness 
values that EPA calculated for LNBs with SOFA and SCR at Unit 2 is 
$2,492, with a 0.95 deciview visibility improvement at the most 
impacted Class I area. Under this approach, EPA would propose to find 
that the cost effectiveness values are reasonable and the visibility 
improvement significant for LNBs with SOFA plus SCR. In addition, the 
costs are within the range that Wyoming in its SIP and EPA in other SIP 
and FIP actions have considered reasonable in the BART context. We 
would propose in the alternative to find that it was unreasonable for 
the State not to determine that LNBs with OFA plus SCR was 
NOX BART for Jim Bridger Units 1 and 2. Though the State is 
requiring the installation of SCR on Units 1 and 2 under its LTS, the 
compliance date for both installations is beyond the five-years allowed 
for BART sources by 40 CFR 51.308(e)(iv). Thus, we would propose to 
disapprove the State's NOX BART determination for Jim 
Bridger Units 1 and 2 and propose a FIP for NOX BART.
    Based on our examination of the cost estimates and the predicted 
visibility improvement (along with a consideration of the other BART 
factors), for our second proposed approach we would propose to find 
that LNBs with SOFA plus SCR at an emission limit of 0.07 lb/MMBtu (30-
day rolling average) is reasonable for NOX BART for Jim 
Bridger Units 1 and 2. We would propose that the FIP NOX 
BART emission limit for PacifiCorp Units 1 and 2 is 0.07 lb/MMBtu (30-
day rolling average).
    Under our second proposed approach, we would propose that 
PacifiCorp meet our proposed emission limit at Jim Bridger Unit 1 and 
2, as expeditiously as practicable, but no later than five years after 
EPA finalizes action on our proposed FIP. This is consistent with

[[Page 34781]]

the requirements of 40 CFR 51.308(e)(iv).\54\
---------------------------------------------------------------------------

    \54\ The proposed regulatory language for this rulemaking only 
covers our first proposed approach. If EPA finalizes an action that 
differs from our first proposed approach for Jim Bridger Units 1 and 
2, we will revise the regulatory language accordingly. If we 
finalize action on our first proposed approach, the regulatory 
language will reflect a compliance deadline of December 31, 2021 for 
Unit 2 and December 31, 2022 for Unit 1. If we finalize action on 
our second proposed approach, the regulatory language would be 
revised to require compliance at Unit 1 and Unit 2 no later than 
five years after we take final action.
---------------------------------------------------------------------------

4. Disapproval of the State's PacifiCorp Naughton Units 1 and 2 
NOX BART Determinations and FIP to Address NOX 
BART
Wyoming's NOX BART Determination
    During the baseline period of 2001-2003, NOX emissions 
from Naughton Unit 1 and Unit 2 were controlled with good combustion 
practices with NOX emission limits of 0.75 lb/MMBtu (3-hour 
block) per boiler, and 0.58 lb/MMBtu (annual) and 0.54 lb/MMBtu 
(annual), respectively. The State determined that new LNBs with OFA, 
new LNBs with OFA and SNCR, and new LNBs with OFA and SCR were all 
technically feasible for controlling NOX emissions from Unit 
1 and Unit 2. The State did not identify any technically infeasible 
options.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's NOX BART analyses for 
Units 1 and 2 is provided in Tables 51 and 52 below. As discussed 
above, the visibility improvement modeling results in these tables were 
developed by EPA because Wyoming did not properly follow the BART 
Guidelines. Baseline NOX emissions are 4,230 tpy for Unit 1 
and 5,109 tpy for Unit 2 based on heat input rates of 1,850 MMBtu/hr 
and 2,400 MMBtu/hr, respectively, and 7,884 hours of operation.

                                            Table 51--Summary of Wyoming's Naughton Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                              (delta
                                                                                                                                           deciview for
                                                           Emission rate                                                                   the  maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (30-day        reduction         costs       effectiveness       cost         percentile
                                                              rolling          (tpy)                          ($/ton)      effectiveness     impact at
                                                             average)                                                                         Bridger
                                                                                                                                            Wilderness
                                                                                                                                             Area) EPA
                                                                                                                                             Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.26           2,334        $993,248            $426  ..............            0.79
New LNBs with OFA and SNCR..............................            0.21           2,699       1,972,363             731          $2,683            0.80
New LNBs with OFA and SCR...............................            0.07           3,720      10,231,210           2,750           8,089            1.07
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                            Table 52--Summary of Wyoming's Naughton Unit 2 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                              (delta
                                                                                                                                             deciview)
                                                                                                                                              (delta
                                                           Emission rate                                                                   deciview for
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental    the  maximum
                   Control technology                         (30-day        reduction         costs       effectiveness       cost            98th
                                                              rolling          (tpy)                          ($/ton)      effectiveness    percentile
                                                             average)                                                                        impact at
                                                                                                                                              Bridger
                                                                                                                                            Wilderness
                                                                                                                                             Area) EPA
                                                                                                                                             Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.26           2,649        $945,683            $357  ..............            0.70
New LNBs with OFA and SNCR..............................            0.21           3,122       2,260,957             724          $2,781            0.74
New LNBs with OFA and SCR...............................            0.07           4,447      12,664,919           2,848           7,852            1.10
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on its consideration of the five factors, the State 
determined new LNBs with OFA was reasonable for NOX BART for 
Unit 1 and Unit 2. The State determined SNCR and SCR were not 
reasonable based on the high cost effectiveness and associated 
visibility improvement. The State determined that the NOX 
BART emission limit for Naughton Unit 1 is 0.26 lb/MMBtu (30-day 
rolling average), and the NOX BART emission limit for 
Naughton Unit 2 is 0.26 lb/MMBtu (30-day rolling average).
EPA's PacifiCorp Naughton Units 1 and 2 NOX BART 
Determination and Proposed FIP for NOX BART
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. We disagree with the State's estimate of baseline 
NOX emissions of 4,230 tpy for Unit 1 and 5,109 tpy for Unit 
2 because these estimates are based on heat input rates of 1,850 MMBtu/
hr and 2,400 MMBtu/hr, respectively rather than an average of actual 
annual emissions. EPA finds that baseline NOX emissions are 
3,553 tpy for Unit 1 and 4,337 tpy for Unit 2 based on the actual 
annual average for the years 2001-2003. A summary of the EPA's 
NOX BART analysis and the visibility impacts is provided in 
Tables 53-56 below.

[[Page 34782]]

                                              Table 53--Summary of EPA's Naughton Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate                                                                    the maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (annual        reduction         costs       effectiveness       cost         percentile
                                                             average)          (tpy)                          ($/ton)      effectiveness     impact at
                                                                                                                                              Bridger
                                                                                                                                            Wilderness
                                                                                                                                               Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.21           2,100        $932,466            $444  ..............            0.84
New LNBs with OFA and SNCR..............................            0.16           2,463       2,258,826             917          $3,650            0.99
New LNBs with OFA and SCR...............................            0.05           3,209       7,437,269           2,318           6,947            1.23
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Naughton Unit 1 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 54 
below.

                    Table 54--Naughton Unit 1: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                                                    Visibility
                                                                    Visibility      improvement     Visibility
                                                                    improvement    (delta dv for    improvement
                                                                   (delta dv for    the maximum    (delta dv for
                          Class I area                              the maximum        98th         the maximum
                                                                       98th         percentile         98th
                                                                    percentile      impact) new     percentile
                                                                    impact) new     LNBs + OFA/     impact) new
                                                                    LNBs + OFA         SNCR       LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Fitzpatrick.....................................................            0.38            0.45            0.56
N. Absaroka.....................................................            0.14            0.16            0.20
Washakie........................................................            0.20            0.23            0.29
Teton...........................................................            0.25            0.29            0.36
Grand Teton.....................................................            0.33            0.39            0.49
Yellowstone.....................................................            0.28            0.32            0.41
----------------------------------------------------------------------------------------------------------------

                                              Table 55--Summary of EPA's Naughton Unit 2 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate                                                                    the maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (annual        reduction         costs       effectiveness       cost         percentile
                                                             average)          (tpy)                          ($/ton)      effectiveness     impact at
                                                                                                                                              Bridger
                                                                                                                                            Wilderness
                                                                                                                                               Area)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.21           2,586        $883,900            $342  ..............            0.97
New LNBs with OFA and SNCR..............................            0.16           3,024       2,510,049             830          $3,713            1.15
New LNBs with OFA and SCR...............................            0.05           3,922       8,843,387           2,255           7,050            1.42
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Naughton Unit 2 also impacts other Class I areas. The visibility 
improvement modeled by EPA at other Class I areas is shown in Table 56 
below.

                    Table 56--Naughton Unit 2: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                                                    Visibility
                                                                    Visibility      improvement     Visibility
                                                                    improvement    (delta dv for    improvement
                                                                   (delta dv for    the maximum    (delta dv for
                          Class I area                              the maximum        98th         the maximum
                                                                       98th         percentile         98th
                                                                    percentile      impact) new     percentile
                                                                    impact) new     LNBs + OFA/     impact) new
                                                                    LNBs + OFA         SNCR       LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Fitzpatrick.....................................................            0.43            0.51            0.64
N. Absaroka.....................................................            0.18            0.21            0.26
Washakie........................................................            0.24            0.28            0.34
Teton...........................................................            0.24            0.37            0.45
Grand Teton.....................................................            0.48            0.56            0.70

[[Page 34783]]

 
Yellowstone.....................................................            0.26            0.30            0.37
----------------------------------------------------------------------------------------------------------------

    EPA does not agree with the State's conclusion that a limit of 0.26 
lb/MMBtu, which can be achieved with the installation and operation of 
new LNBs with SOFA, is reasonable for BART for Naughton Units 1 and 2. 
We propose to find that Wyoming did not properly follow the 
requirements of the BART Guidelines in determining NOx BART for these 
units. Specifically, we propose to find that Wyoming did not properly 
or reasonably conduct certain requirements of the BART analyses.
    As discussed in detail above, because Wyoming relied on visibility 
modeling methodologies that are inconsistent with the statutory and 
regulatory requirements, we do not consider Wyoming's analysis of 
visibility improvement for the NOX BART to be reasonable for 
Naughton Units 1 and 2. We propose to find that Wyoming's analyses for 
these Units are inconsistent with the statutory and regulatory 
requirement that ``the degree of improvement in visibility which may 
reasonably be anticipated to result from the use of such technology.''
    Also, we are not relying on the State's costs due to reasons stated 
in section VII.C.3.b. We propose to find that Wyoming did not properly 
or reasonably ``take into consideration the costs of compliance.'' 
Thus, the State's BART analyses for Naughton Units 1 and 2 do not meet 
the requirements of the CAA and RHR, and we are proposing to disapprove 
the analyses and the State's NOX BART determinations. We are 
proposing a FIP for NOX BART to fill the gaps left by our 
disapproval, as explained below.
    Our analysis follows our BART Guidelines. With the exception of the 
NOX emission limits, the visibility improvement analyses, 
and the cost effectiveness analyses, EPA is proposing to find that the 
Wyoming's regional haze NOX BART analysis for Naughton Units 
1 and 2, fulfills all the relevant requirements of CAA Section 169A and 
the RHR.
    EPA's NOX BART analysis and the visibility impacts for 
Naughton Units 1 and 2 are summarized in Tables 53-56 above and 
detailed information can be found in the docket.\55\ EPA's cost 
analysis estimated the cost-effectiveness value for LNBs with OFA and 
SCR at Unit 1 is $2,318/ton with a 1.23 dv visibility improvement at 
the most impacted Class I area. The cost effectiveness value for LNBs 
with OFA and SCR at Unit 2 is estimated at $2,255/ton, with a 1.42 dv 
visibility improvement at the most impacted Class I area. In addition, 
the installation of SCR will also have substantial visibility benefits 
for other Class I areas, besides the most impacted area. The cumulative 
visibility improvement is 3.54 dv for Unit 1 and 4.18 dv for Unit 2. 
EPA followed the BART Guidelines in developing these cost-effectiveness 
values, which are reasonable and the visibility improvement is 
significant for new LNBs with OFA plus SCR. The costs and visibility 
improvements are within the range that Wyoming in its SIP and EPA in 
other SIP and FIP actions have considered reasonable in the BART 
context.
---------------------------------------------------------------------------

    \55\ Detailed supporting information for our cost and visibility 
improvement analyses can be found in the Docket (see Staudt memos 
and EPA BART and RP Modeling for Wyoming, respectively).
---------------------------------------------------------------------------

    Based on our examination of the cost estimates and the predicted 
visibility improvement (along with a consideration of the other BART 
factors), we propose to find that new LNBs with OFA plus SCR at an 
emission limit of 0.07 lb/MMBtu (30-day rolling average) is reasonable 
and consistent with the CAA and BART Guidelines requirements for 
NOX BART for Naughton Units 1 and 2. We are proposing that 
the FIP NOX BART emission limit for PacifiCorp Naughton 
Units 1 and 2 is 0.07 lb/MMBtu (30-day rolling average).
    We propose that PacifiCorp meet our proposed emission limit at 
Naughton Unit 1 and 2, as expeditiously as practicable, but no later 
than five years after EPA finalizes action on our proposed FIP. This is 
consistent with the requirements of 40 CFR 51.308(e)(iv).
    We are also asking if interested parties have additional 
information regarding the BART factors and EPA's proposed 
determination, for example our weighing of average costs, incremental 
costs, visibility improvement, and timing of installation of such 
controls, and in light of such information, whether the interested 
parties think the Agency should consider another BART control 
technology option that could be finalized either instead of, or in 
conjunction with, BART as proposed. The Agency will take the comments 
and testimony received, as well as any further SIP revisions submitted 
by the State, into consideration in our final promulgation. 
Supplemental information received may lead the Agency to adopt final 
SIP and/or FIP regulations that reflect a different BART control 
technology option, or impact other proposed regulatory provisions, 
which differ from this proposal.
5. Disapproval of the State's PacifiCorp Wyodak Unit 1 NOX 
BART Determination and FIP To Address NOX BART
Wyoming's NOX BART Determination
    During the baseline period, Wyodak Unit 1 was controlled for 
NOX emissions with early generation LNBs with emission 
limits of 0.70 lb/MMBtu (3-hour block) and 0.31 lb/MMbtu (annual). The 
State determined new LNBs with OFA, existing LNBs with ROFA, new LNBs 
with OFA plus SNCR, and new LNBs with OFA plus SCR were technically 
feasible for controlling NOX emissions. The State did not 
identify any technically infeasible control options.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's NOX BART analyses for 
Unit 1 is provided in Table 57 below. Baseline NOX emissions 
are 5,744 tpy based on the unit heat input rate of 4,700 MMBtu/hr and 
7,884 hours of operation per year. As discussed above, the visibility 
improvement modeling results in these tables were developed by EPA 
because Wyoming

[[Page 34784]]

did not properly follow the BART Guidelines.

                                             Table 57--Summary of Wyoming's Wyodak Unit 1 NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate                                                                    the maximum
                                                            (lb/MMBtu)       Emission       Annualized     Average cost     Incremental        98th
                   Control technology                         (30-day        reduction         costs       effectiveness       cost         percentile
                                                              rolling          (tpy)                          ($/ton)      effectiveness  impact at Wind
                                                             average)                                                                      Cave National
                                                                                                                                            Park)  EPA
                                                                                                                                             analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNBs with OFA...........................................            0.23           1,483      $1,306,203            $881  ..............            0.25
LNBs with OFA and SNCR..................................            0.18           2,409       2,306,728             958          $1,080            0.40
LNBs with OFA and SCR...................................            0.07           4,447      18,910,781           4,252           8,147            0.72
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on its consideration of the five factors, the State 
determined LNBs with OFA was reasonable for NOX BART for 
Unit 1. The State determined other control technologies were not 
reasonable based on the high-cost effectiveness values and low 
visibility improvement. The State determined the NOX BART 
emission limit for Wyodak Unit 1 is 0.23 lb/MMBtu (30-day rolling 
average).
EPA's Conclusions on Wyodak Unit 1 NOX BART Determination 
and FIP for NOX BART
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. We disagree with the State's estimate of baseline 
NOX emissions of 5,744 tpy because these estimates are based 
on the unit heat input rate of 4,700 MMBtu/hr and 7,884 hours of 
operation per year rather than an average of actual annual emissions. 
EPA finds that baseline NOX emissions are 4,615 tpy based on 
the actual annual average for the years 2001-2003. A summary of the 
EPA's NOX BART analysis and the visibility impacts is 
provided in Tables 58 and 59 below.

                                                  Table 58--Summary of EPA's Wyodak's NOX BART Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate     Emission                      Average cost     Incremental     the maximum
                   Control technology                       (lb/MMBtu)       reduction      Annualized     effectiveness       cost            98th
                                                              (annual          (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                               Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
New LNBs with OFA.......................................            0.19           1,239      $1,272,427          $1,027  ..............            0.24
New LNBs with OFA and SNCR..............................            0.15           1,914       3,787,466           1,979          $3,725            0.38
New LNBs with OFA and SCR...............................            0.05           3,735      14,386,417           3,852           5,822            0.71
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Wyodak also impacts one other Class I area. The visibility 
improvement EPA modeled at the other Class I area is shown in Table 59 
below.

                         Table 59--Wyodak: Visibility Improvement at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                                                    Visibility
                                                                    Visibility      improvement     Visibility
                                                                    improvement    (delta dv for    improvement
                                                                   (delta dv for    the maximum    (delta dv for
                          Class I area                              the maximum        98th         the maximum
                                                                       98th         percentile         98th
                                                                    percentile     impact) - new    percentile
                                                                   impact) - new    LNBs + OFA/    impact) - new
                                                                    LNBs + OFA         SNCR       LNBs + OFA/SCR
----------------------------------------------------------------------------------------------------------------
Badlands........................................................            0.17            0.23            0.45
----------------------------------------------------------------------------------------------------------------

    EPA does not agree with the State's conclusion that a limit of 0.23 
lb/MMBtu is reasonable for NOX BART for Wyodak Unit 1, which 
can be achieved with the installation and operation of new LNBs with 
OFA. We propose to find that Wyoming did not properly follow the 
requirements of the BART Guidelines in determining NOx BART for this 
unit. Specifically, we propose to find that Wyoming did not properly or 
reasonably conduct certain requirements of the BART analysis.
    As discussed in detail above, because Wyoming relied on visibility 
modeling methodologies that are inconsistent with the statutory and 
regulatory requirements, we do not consider Wyoming's analysis of 
visibility improvement for the NOX BART to be reasonable for 
Wyodak Unit 1. We propose to find that Wyoming's analysis for this Unit 
is inconsistent with the statutory and regulatory requirement that 
``the degree of improvement in visibility which may reasonably be

[[Page 34785]]

anticipated to result from the use of such technology.''
    Also, we are not relying on the State's costs due to reasons stated 
in section VII.C.3.b of this notice. We propose to find that Wyoming 
did not properly or reasonably ``take into consideration the costs of 
compliance.'' Thus, the State's BART analysis for Wyodak Unit 1 does 
not meet the requirements of the CAA and RHR, and we are proposing to 
disapprove the analysis and the State's NOX BART 
determination. We are proposing a FIP for NOX BART to fill 
the gap left by our disapproval, as explained below.
    Our analysis follows our BART Guidelines. With the exception of the 
NOX emission limits, the visibility improvement analyses, 
and the cost-effectiveness analyses, EPA is proposing to find that the 
Wyoming's regional haze NOX BART analysis for Wyodak Unit 1 
fulfills all the relevant requirements of CAA Section 169A and the RHR.
    EPA's NOX BART analysis and the visibility impacts for 
Wyodak Unit 1 are summarized in Tables 58-59 above and detailed 
information can be found in the docket.\56\ In particular, the cost 
effectiveness value for new LNB with OFA plus SNCR at this unit is 
$1,979/ton with a visibility improvement at the most impacted Class I 
area of 0.38 deciviews. The costs are within the range that EPA in 
other SIP and FIP actions has considered reasonable and consistent with 
the BART Guidelines.
---------------------------------------------------------------------------

    \56\ Detailed supporting information for our cost and visibility 
improvement analyses can be found in the Docket (see Staudt memos 
and EPA BART and RP Modeling for Wyoming, respectively.
---------------------------------------------------------------------------

    Based on our examination of the costs estimates, emission 
reductions, and the predicted visibility improvement, we propose to 
find that new LNBs with OFA plus SNCR at an emission limit of 0.17 lb/
MMBtu (30-day rolling average) is reasonable and consistent with the 
CAA and BART Guideline requirements for NOX BART for Wyodak 
Unit 1. We are proposing that the FIP NOX BART emission 
limit for PacifiCorp Wyodak Unit 1 is 0.17 lb/MMBtu (30-day rolling 
average).
    We have eliminated the highest performing option from 
consideration--new LNBs with OFA plus SCR. Although the cost-
effectiveness and visibility improvement are within the range of other 
EPA FIP actions, we find that the cumulative visibility improvement of 
1.16 deciviews for new LNBs with OFA plus SCR is low compared to the 
cumulative visibility benefits that will be achieved by requiring SCR 
at Dave Johnston Unit 3 (2.92 dv), Laramie River Unit 1 (2.12 dv), 
Laramie River Unit 2 (1.97 dv), Laramie River Unit 3 (2.29 dv), 
Naughton Unit 1 (3.54 dv), and Naughton Unit 2 (4.18 dv).
    We propose that PacifiCorp meet our proposed emission limit at 
Wyodak Unit 1, as expeditiously as practicable, but no later than five 
years after EPA finalizes action on our proposed FIP. This is 
consistent with the requirements of 40 CFR 51.308(e)(iv).
    We are also asking if interested parties have additional 
information regarding the BART factors and EPA's proposed 
determination, for example our weighing of average costs, incremental 
costs, visibility improvement, and timing of installation of such 
controls, and in light of such information, whether the interested 
parties think the Agency should consider another BART control 
technology option that could be finalized either instead of, or in 
conjunction with, BART as proposed. The Agency will take the comments 
and testimony received, as well as any further SIP revisions submitted 
by the State, into consideration in our final promulgation. 
Supplemental information received may lead the Agency to adopt final 
SIP and/or FIP regulations that reflect a different BART control 
technology option, or impact other proposed regulatory provisions, 
which differ from this proposal.

B. Disapproval of the State's NOX Reasonable Progress 
Determinations and Federal Implementation Plan for NOX 
Reasonable Progress Determinations and Limits

    We are proposing to disapprove the State's reasonable progress 
determination for PacifiCorp Dave Johnston Unit 1 and Unit 2, and we 
are proposing a reasonable progress NOX FIP for these units, 
as explained below. As noted above, the State provided four-factor 
analyses that evaluated the required factors. However, due to 
deficiencies in the control cost estimates, EPA conducted its own cost 
analyses for Dave Johnston Unit 1 and 2. The cost analysis was done in 
the same manner as described for BART sources in Section VII.C.
    We concluded that it is also appropriate to consider a fifth factor 
for these units for evaluating potential reasonable progress control 
options--the degree of visibility improvement that may reasonably be 
anticipated from the use of the reasonable progress controls. Our 
reasonable progress guidance contemplates that states (or EPA in lieu 
of a state) may be able to consider other relevant factors for 
reasonable progress sources (see EPA's Guidance for Setting Reasonable 
Progress Goals under the Regional Haze Program, (``Reasonable Progress 
Guidance''), pp. 2-3, July 1, 2007). We find it appropriate, in certain 
circumstances, to consider visibility improvement when evaluating 
potential reasonable progress controls. Thus, in the same manner as 
described for BART sources in Section VII.C, EPA conducted visibility 
improvement modeling for Dave Johnston Units 1 and 2.
1. PacifiCorp Dave Johnston--Units 1 and 2
Background
    PacifiCorp's Dave Johnston power plant is comprised of four units 
burning pulverized subbituminous Powder River Basin coal. Units 3 and 4 
are subject to BART, as described above. Units 1 and 2 are nominal 106 
MW dry bottom wall-fired boilers. Unit 1 began operation in 1958 and 
Unit 2 in 1960.
Wyoming's NOX Reasonable Progress Determinations
    Unit 1 and Unit 2 are currently uncontrolled for NOX 
emissions. The State determined that LNBs, LNBs with OFA, SNCR, and SCR 
were technically feasible for controlling NOX emissions. The 
State did not identify any technically infeasible control options.
    The State did not identify any energy or non-air quality 
environmental impacts that would preclude the selection of any of the 
controls evaluated, and there are no remaining-useful-life issues for 
this source. A summary of the State's NOX reasonable 
progress analyses for Unit 1 and Unit 2, along with our visibility 
modeling results, are provided in Tables 60 and 61 below. Baseline 
NOX emissions are 2,256 tpy for Unit 1 and 2,174 tpy for 
Unit 2 based on 2002 actual emissions. Wyoming did not provide 
controlled emission rates in their reasonable progress analysis.

[[Page 34786]]

                   Table 60--Summary of Dave Johnston Unit 1 NOX Reasonable Progress Analysis
----------------------------------------------------------------------------------------------------------------
                                                                                                    Visibility
                                                                                                    improvement
                                                                                                   (delta dv for
                                                                                                    the maximum
                                      Control        Emission       Annualized     Average cost        98th
       Control technology         efficiency (%)     reduction         costs       effectiveness    percentile
                                                       (tpy)                          ($/ton)     impact at Wind
                                                                                                   Cave National
                                                                                                     Park) EPA
                                                                                                     Analysis
----------------------------------------------------------------------------------------------------------------
LNBs............................              51           1,150        $631,000            $528            0.37
LNBs with OFA...................              65           1,466         962,000             632            0.49
SNCR............................              40             902       2,490,000           2,659            0.26
SCR.............................              80           1,804       3,390,000           1,810            0.58
----------------------------------------------------------------------------------------------------------------

                   Table 61--Summary of Dave Johnston Unit 2 NOX Reasonable Progress Analysis
----------------------------------------------------------------------------------------------------------------
                                                                                                    Visibility
                                                                                                    improvement
                                                                                                   (delta dv for
                                                                                                    the maximum
                                      Control        Emission       Annualized     Average cost        98th
       Control technology         efficiency (%)     reduction         costs       effectiveness    percentile
                                                       (tpy)                          ($/ton)     impact at Wind
                                                                                                   Cave National
                                                                                                     Park) EPA
                                                                                                     Analysis
----------------------------------------------------------------------------------------------------------------
LNBs............................              51           1,108        $631,000            $538            0.38
LNBs with OFA...................              65           1,413         962,000             644            0.49
SNCR............................              40             869       2,490,000           2,709            0.28
SCR.............................              80           1,739       3,390,000           1,844            0.58
----------------------------------------------------------------------------------------------------------------

    The State estimated that it would take nearly five and a half years 
for NOX reduction strategies to become effective. The State 
determined that roughly two years would be necessary for the State to 
develop the necessary regulations to implement the selected control 
measures. The State estimated that it would take up to a year for the 
source to secure the capital necessary to purchase emission control 
devices and approximately 18 months would be required for the company 
to design, fabricate, and install SCR or SNCR technology. Because there 
are two boilers being evaluated at Dave Johnston, the State determined 
an additional year may be required for staging the installation 
process.
    The State determined that no controls were reasonable for this 
planning period. The State cited that the four-factor analysis was 
limited, in that no guidance was provided by EPA for identifying 
significant sources and EPA did not establish contribution to 
visibility impairment thresholds (a potential fifth factor for 
reasonable progress determinations).\57\ The State further claims that 
the State cannot, per Wyoming Statute 35-11-202, establish emission 
control requirements except through state rule or regulation. 
Furthermore, the Wyoming statute requires the State to consider the 
character and degree of injury of the emissions involved. In this case, 
the State claims it would need to have visibility modeling that 
assessed the degree of injury caused by the emissions, which the State 
does not have. The State believes it has taken a strong and reasonable 
first step in identifying potential contributors to visibility 
impairment, and that the next step of creating an appropriate rule or 
regulation will be accomplished in the next SIP revision.
---------------------------------------------------------------------------

    \57\ States must consider the four factors as listed above but 
can also take into account other relevant factors for the reasonable 
progress sources identified (see EPA's Guidance for Setting 
Reasonable Progress Goals under the Regional Haze Program, (``EPA's 
Reasonable Progress Guidance''), p. 2-3, July 1, 2007).
---------------------------------------------------------------------------

EPA's Conclusions on Dave Johnston Units 1 and 2 NOX 
Reasonable Progress Determination and FIP for NOX Reasonable 
Progress Controls
    The EPA agrees with the State's analysis pertaining to energy or 
non-air quality environmental impacts and remaining-useful-life for 
this source. We disagree with the State's estimate of baseline 
NOX emissions of 2,256 tpy for Unit 1 and 2,174 tpy for Unit 
2, which were based on 2002 actual emissions. EPA's estimate of 
baseline NOX emissions are 2,188 tpy for Unit 1 and 2,161 
tpy for Unit 2 based on the actual annual average for the years 2001-
2003. A summary of the EPA's NOX BART analysis and the 
visibility impacts is provided in Tables 62-65 below.

[[Page 34787]]

                                    Table 62--Summary of EPA's Dave Johnston Unit 1 NOX Reasonable Progress Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate     Emission                      Average cost     Incremental     the maximum
                   Control technology                       (lb/MMBtu)       reduction      Annualized     effectiveness       cost            98th
                                                              (annual          (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                               Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNBs with OFA...........................................            0.20           1,226      $1,187,179            $968  ..............            0.31
LNBs with OFA and SNCR..................................            0.15           1,466       2,087,189           1,423          $3,743            0.35
LNBs with OFA and SCR...................................            0.05           1,947       6,417,536           3,296           9,004            0.44
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Dave Johnston Unit 1 also impacts other Class I areas. The 
visibility improvement EPA modeled at other Class I areas is shown in 
Table 63 below.

                         Table 63--Visibility Improvement Modeled at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                            impact) - LNBs +  impact) - LNBs +  impact) - LNBs +
                                                                   OFA            OFA/SNCR           OFA/SCR
----------------------------------------------------------------------------------------------------------------
Badlands..................................................              0.17              0.16              0.25
Mt. Zirkel................................................              0.06              0.08              0.13
Rawah.....................................................              0.10              0.12              0.15
Rocky Mountain............................................              0.13              0.16              0.22
----------------------------------------------------------------------------------------------------------------

                                    Table 64--Summary of EPA's Dave Johnston Unit 2 NOX Reasonable Progress Analysis
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Visibility
                                                                                                                                            improvement
                                                                                                                                           (delta dv for
                                                           Emission rate     Emission                      Average cost     Incremental     the maximum
                   Control technology                       (lb/MMBtu)       reduction      Annualized     effectiveness       cost            98th
                                                              (annual          (tpy)           costs          ($/ton)      effectiveness    percentile
                                                             average)                                                                     impact at Wind
                                                                                                                                           Cave National
                                                                                                                                               Park)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LNBs with OFA...........................................            0.20           1,180      $1,188,797          $1,007  ..............            0.29
LNBs with OFA and SNCR..................................            0.15           1,425       2,100,619           1,474          $3,718            0.33
LNBs with OFA and SCR...................................            0.05           1,916       6,432,035           3,357           8,830            0.42
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Dave Johnston Unit 1 also impacts other Class I areas. The 
visibility improvement EPA modeled at other Class I areas is shown in 
Table 65 below.

                         Table 65--Visibility Improvement Modeled at Other Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                               Visibility        Visibility        Visibility
                                                               improvement       improvement       improvement
                                                              (delta dv for     (delta dv for     (delta dv for
                       Class I area                         the maximum 98th  the maximum 98th  the maximum 98th
                                                               percentile        percentile        percentile
                                                            impact) - LNBs +  impact) - LNBs +  impact) - LNBs +
                                                                   OFA            OFA/SNCR           OFA/SCR
----------------------------------------------------------------------------------------------------------------
Badlands..................................................              0.14              0.17              0.24
Mt. Zirkel................................................              0.06              0.09              0.12
Rawah.....................................................              0.09              0.11              0.15
Rocky Mountain............................................              0.13              0.16              0.21
----------------------------------------------------------------------------------------------------------------

    We disagree with the State's reasoning for not adopting reasonable 
progress controls for Dave Johnston Unit 1 and Unit 2. If the State 
determined that it needed to adopt a rule or perform modeling to 
adequately assess and, if warranted, require reasonable progress 
controls, the State should have completed these steps before it 
submitted its regional haze SIP. The RHR does not allow for commitments 
to potentially implement strategies at some later date that are 
identified under reasonable progress or for the State to take credit 
for such commitments.

[[Page 34788]]

    In addition, the cost effectiveness value for LNBs with OFA at Unit 
1 is $968/ton and $1,007/ton at Unit 2. These values are very 
reasonable and far less than some of the cost effectiveness values the 
State found reasonable in making its BART determinations. Given 
predicted visibility improvement of approximately 0.30 deciviews per 
unit at the most impacted Class I area and the fact that Wyoming's 
reasonable progress goals will not meet the URP, we find that it was 
unreasonable for the State to reject these very inexpensive controls. 
Thus, we are proposing to disapprove the State's NOX 
reasonable progress determination for Dave Johnston Unit 1 and Unit 2 
and proposing a FIP for NOX reasonable progress controls as 
explained below.
    Based on our examination of the State's costs estimates, emission 
reductions, and the predicted visibility improvement, we propose to 
find that LNBs with OFA at an emission limit of 0.22 lb/MMBtu (30-day 
rolling average) is reasonable for NOX reasonable progress 
controls for Dave Johnston Units 1 and 2. We are proposing that the FIP 
NOX reasonable progress emission limit for PacifiCorp Dave 
Johnston Unit 1 and Unit 2 is 0.22 lb/MMBtu (30-day rolling average).
    We propose that PacifiCorp meet our proposed emission limit at Dave 
Johnston Units 1 and 2 as expeditiously as practicable, but no later 
than July 31, 2018. This is consistent with the requirement that the 
SIP cover an initial planning period that ends July 31, 2018.

C. Reasonable Progress Goals

    We are proposing to impose reasonable progress controls on Dave 
Johnston Units 1 and 2, as well as more stringent NOX BART 
controls on PacifiCorp Dave Johnston Unit 3 and Unit 4, PacifiCorp 
Naughton Unit 1 and Unit 2, PacifiCorp Wyodak Unit 1, and Basin 
Electric Laramie River Units 1, 2, and 3, than WRAP assumed in modeling 
Wyoming's RPGs.
    We could not re-run the WRAP modeling due to time and resource 
constraints, but anticipate that the additional controls would result 
in an increase in visibility improvement during the 20% worst days. As 
noted in our analyses, many of our proposed controls would result in 
significant incremental visibility benefits when modeled against 
natural background. We anticipate that this would translate into 
measurable improvement if modeled on the 20% best days as well. While 
we expect our proposed controls will result in additional visibility 
improvement, we do not expect that these improvements will result in 
the State achieving the URP. For some of the reasons discussed in 
section VII.D.3, in particular, emissions from sources outside the WRAP 
modeling domain, along with our consideration of the statutory 
reasonable progress factors, we find it reasonable for the State to not 
achieve the URP during this planning period. We expect the State to 
quantify the visibility improvement in its next regional haze SIP 
revision.
    For purposes of this action, we are proposing RPGs that are 
consistent with the additional controls we are proposing. While we 
would prefer to quantify the RPGs, we note that the RPGs themselves are 
not enforceable values. The more critical elements for our FIP are the 
emissions limits we are proposing to impose, which will be enforceable.

D. Federal Monitoring, Recordkeeping, and Reporting Requirements

    The CAA requires that SIPs, including the regional haze SIP, 
contain elements sufficient to ensure emission limits are practically 
enforceable.\58\ Other applicable regulatory provisions are contained 
in Appendix V to Part 51--Criteria for Determining the Completeness of 
Plan Submissions.\59\ We are proposing to find that the State's 
regional haze SIP does not contain adequate monitoring, recordkeeping 
and reporting requirements. Chapter 6.4, Section V of the SIP contains 
monitoring and reporting requirements that we find inadequate for 
numerous reasons, summarized as follows: (1) The State's language 
includes references to WAQSR Chapters that EPA has not approved as part 
of the SIP and are thus not federally enforceable. These references 
should be to the appropriate sections in the CFR; (2) Definitions have 
not been included; (3) The State's language allows for data 
substitution pursuant to 40 CFR part 75. The data substitution 
procedures of 40 CFR part 75 were never intended to apply to BART 
sources; (4) There are numerous language clarifications and rewordings 
needed; and (5) The State did not include appropriate recordkeeping 
language.\60\
---------------------------------------------------------------------------

    \58\ CAA Section 110(a)(2) states that SIPs ``shall (A) include 
enforceable emission limitations and other control measures, means, 
or techniques (including economic incentives such as fees, 
marketable permits, and auctions of emissions rights), as well as 
schedules and timetables for compliance, as may be necessary or 
appropriate to meet the applicable requirements of this chapter; (C) 
include a program to provide for the enforcement of the measures 
described in subparagraph (A), and regulation of the modification 
and construction of any stationary source within the areas covered 
by the plan as necessary to assure that national ambient air quality 
standards are achieved, including a permit program as required in 
parts C and D of this subchapter; (F) require, as may be prescribed 
by the Administrator--(i) the installation, maintenance, and 
replacement of equipment, and the implementation of other necessary 
steps, by owners or operators of stationary sources to monitor 
emissions from such sources, (ii) periodic reports on the nature and 
amounts of emissions and emissions-related data from such sources, 
and (iii) correlation of such reports by the State agency with any 
emission limitations or standards established pursuant to this 
chapter, which reports shall be available at reasonable times for 
public inspection''
    \59\ Appendix V part 51 states in section 2.2 that complete SIPs 
contain: ``(g) Evidence that the plan contains emission limitations, 
work practice standards and recordkeeping/reporting requirements, 
where necessary, to ensure emission levels''; and ``(h) Compliance/
enforcement strategies, including how compliance will be determined 
in practice.''
    \60\ On July 6, 2011, EPA sent an email to the State with 
detailed comments (that are summarized above) on the State's 
monitoring, recordkeeping, and reporting requirements in Chapter 
6.4, Section V of the SIP. The July 6, 2011 email from Laurel 
Dygowski, EPA Region 8, to Tina Anderson, State of Wyoming, is 
included in the Supporting and Related Materials section of the 
docket.
---------------------------------------------------------------------------

    EPA is proposing to disapprove the State's monitoring, 
recordkeeping, and reporting requirements in Chapter 6.4 of the SIP. 
EPA is proposing regulatory language as part of our FIP that specifies 
monitoring, recordkeeping, and reporting requirements for all BART and 
reasonable progress sources. For purposes of consistency, EPA is 
proposing to adopt language that is the same as we have adopted for 
other states in Region 8.

E. Federal Implementation Plan for the Long-Term Strategy

    We are proposing regulatory language as part of our FIP that 
specifies NOX emission limits and compliance schedules for 
the following sources: PacifiCorp Dave Johnston Units 1-4, PacifiCorp 
Jim Bridger Units 1 and 2, PacifiCorp Naughton Unit 1 and Unit 2, 
PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River Units 1, 2, 
and 3. We are also proposing monitoring, recordkeeping, and reporting 
requirements for all BART SIP and FIP sources and for Dave Johnston 
Units 1 and 2. We are proposing this regulatory language to fill the 
gap in the LTS that would be left by our proposed partial disapproval 
of the LTS.

F. Federal Implementation Plan for Coordination of RAVI and Regional 
Haze Long-Term Strategy

    In response to EPA's RAVI rules, Wyoming adopted WAQSR Chapter 9, 
Section 2. EPA approved WAQSR Chapter 9, Section 2 as part of the SIP 
on July 28, 2004 (69 FR 44965). As discussed above, the State is 
required to coordinate the review of its RAVI and regional haze LTS and 
conduct the

[[Page 34789]]

reviews together. WAQSR Chapter 9, Section 2(f) requires the State to 
review its RAVI LTS every three years, which does not coordinate with 
the five-year review for the State's regional haze LTS. Thus, we are 
proposing to disapprove the State's SIP because it does not meet the 
requirements of 40 CFR 51.306(c). We are proposing a FIP in which EPA 
commits to coordinating the State's RAVI LTS review with the regional 
haze LTS review. Thus, EPA is committing to provide a review of the 
State's RAVI LTS every five years in coordination with the State's 
regional haze LTS review. EPA is proposing that our review of the 
State's RAVI LTS will follow those items as indicated by 40 CFR 
51.306(c).

IX. EPA's Proposed Action

    EPA is proposing to partially approve and partially disapprove a 
regional haze SIP revision submitted by the State of Wyoming on January 
12, 2011. Specifically, we are proposing to disapprove the following:
     The State's NOX BART determinations for 
PacifiCorp Dave Johnston Unit 3 and Unit 4, PacifiCorp Naughton Unit 1 
and Unit 2, PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River 
Units 1, 2, and 3.
     The State's NOX reasonable progress 
determination for PacifiCorp Dave Johnston Units 1 and 2.
     Wyoming's RPGs.
     The State's monitoring and recordkeeping requirements in 
Chapter 6.4 of the SIP.
     Portions of the State's LTS that rely on or reflect other 
aspects of the regional haze SIP we are proposing to disapprove.
     The provisions necessary to meet the requirements for the 
coordination of the review of the RAVI and the regional haze LTS.
    We are proposing to approve the remaining aspects of the State's 
January 12, 2011, SIP submittal. We are also seeking comment on an 
alternative proposal related to the State's NOX BART 
determination for PacifiCorp Jim Bridger Units 1 and 2.
    We are proposing the promulgation of a FIP to address the 
deficiencies in the Wyoming regional haze SIP that we have identified 
in this proposal. The proposed FIP includes the following elements:
     NOX BART determinations and limits for 
PacifiCorp Dave Johnston Unit 3 and Unit 4, PacifiCorp Naughton Unit 1 
and Unit 2, PacifiCorp Wyodak Unit 1, and Basin Electric Laramie River 
Units 1, 2, and 3.
     NOX reasonable progress determination and 
limits for PacifiCorp Dave Johnston Units 1 and 2.
     RPGs consistent with the SIP limits proposed for approval 
and the proposed FIP limits.
     Monitoring, record-keeping, and reporting requirements 
applicable to all BART and reasonable progress sources for which there 
is a SIP or FIP emissions limit.
     LTS elements pertaining to emission limits and compliance 
schedules for the proposed BART and reasonable progress FIP limits.
     Provisions to ensure the coordination of the RAVI and 
regional haze LTS.

X. 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 (58 FR 51735, October 4, 1993) and is 
therefore not subject to review under Executive Orders 12866 and 13563 
(76 FR 3821, January 21, 2011). As discussed in section C below, the 
proposed FIP applies to only five facilities. It is therefore not a 
rule of general applicability.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Burden is defined at 5 CFR 1320.3(b). Because the proposed FIP applies 
to just five facilities, the Paperwork Reduction Act does not apply. 
See 5 CFR 1320(c).

C. 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 today's 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 today's proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. The Regional 
Haze FIP that EPA is proposing for purposes of the regional haze 
program consists of imposing federal controls to meet the BART 
requirement for NOX emissions on specific units at five 
sources in Wyoming, and imposing controls to meet the reasonable 
progress requirement for NOX emissions at one additional 
source in Wyoming. The net result of this FIP action is that EPA is 
proposing direct emission controls on selected units at only five 
sources. The sources in question are each large electric generating 
plants that are not owned by small entities, and therefore are not 
small entities. The proposed partial approval of the SIP, if finalized, 
merely approves state law as meeting Federal requirements and imposes 
no additional requirements beyond those imposed by state law. See Mid-
Tex Electric Cooperative, Inc. v. FERC, 773 F.2d 327 (D.C. Cir. 1985)
    We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

D. Unfunded Mandates Reform Act (UMRA)

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for federal agencies to assess the 
effects of their regulatory actions on State, local, and Tribal 
governments and the private sector. Under section 202 of UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and 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 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

[[Page 34790]]

205 of UMRA do not apply when they are inconsistent with applicable 
law. Moreover, section 205 of UMRA allows 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 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 
proposals with significant federal intergovernmental mandates, and 
informing, educating, and advising small governments on compliance with 
the regulatory requirements.
    Under Title II of UMRA, 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 by State, 
local, or Tribal governments or the private sector in any one year. In 
addition, this proposed rule does not contain a significant federal 
intergovernmental mandate as described by section 203 of UMRA nor does 
it contain any regulatory requirements that might significantly or 
uniquely affect small governments.

E. Executive Order 13132: Federalism

    Federalism (64 FR 43255, August 10, 1999) revokes and replaces 
Executive Orders 12612 (Federalism) and 12875 (Enhancing the 
Intergovernmental Partnership). Executive Order 13132 requires 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.'' ``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.'' Under Executive Order 13132, 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 state and local governments, or EPA 
consults with state and local officials early in the process of 
developing the proposed regulation. 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 proposed regulation.
    This rule 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, because it 
merely addresses the State not fully meeting its obligation to prohibit 
emissions from interfering with other states measures to protect 
visibility established in the CAA. Thus, Executive Order 13132 does not 
apply to this action. In the spirit of Executive Order 13132, and 
consistent with EPA policy to promote communications between EPA and 
state and local governments, EPA specifically solicits comment on this 
proposed rule from state and local officials.

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

    Executive Order 13175, entitled Consultation and Coordination with 
Indian Tribal Governments (65 FR 67249, November 9, 2000), requires 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.'' 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.

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

    EPA interprets EO 13045 (62 FR 19885, April 23, 1997) as applying 
only to those regulatory actions that concern health or safety risks, 
such that the analysis required under section 5-501 of the EO has the 
potential to influence the regulation. This action is not subject to EO 
13045 because it implements specific standards established by Congress 
in statutes. However, to the extent this proposed rule will limit 
emissions of NOX, SO2, and PM, the rule will have 
a beneficial effect on children's health by reducing air pollution.

H. 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.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to 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 EPA to provide 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards.
    This proposed rulemaking does not involve technical standards. 
Therefore, EPA is not considering the use of any voluntary consensus 
standards.

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

    Executive Order 12898 (59 FR 7629, February 16, 1994), establishes 
federal executive policy on environmental justice. 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.
    We have determined that this proposed action, if finalized, will 
not have disproportionately high and adverse human health or 
environmental effects on minority or low-income populations because it 
increases the level of environmental protection for all affected 
populations without having any disproportionately high and adverse 
human health or environmental effects on any population, including any 
minority or low-income population. This proposed rule limits emissions 
of NOX from five facilities in Wyoming.

[[Page 34791]]

The partial approval of the SIP, if finalized, merely approves state 
law as meeting Federal requirements and imposes no additional 
requirements beyond those imposed by state law.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, does not 
apply because this action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental 
relations, Nitrogen dioxide, Particulate matter, Reporting and 
recordkeeping requirements, Sulfur oxides, Volatile organic compounds.

    Dated: May 23, 2013.
Shaun L. McGrath,
Regional Administrator Region 8.

    40 CFR part 52 is proposed to be amended as follows:

PART 52--[AMENDED]

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. Add section 52.2636 to read as follows:

Sec.  52.2636  Federal implementation plan for regional haze.\61\
---------------------------------------------------------------------------

    \61\ The proposed regulatory language only reflects our proposed 
action. If EPA's final action differs from our proposed action, the 
regulatory language will be amended, as necessary, to reflect the 
Agency's final decision.
---------------------------------------------------------------------------

    (a) Applicability. This section applies to each owner and operator 
of the following emissions units in the State of Wyoming for which EPA 
proposes to approve the State's BART determination:
    FMC Westvaco Trona Plant Units NS-1A and NS-1B (PM and 
NOX);
    TATA Chemicals Partners (previously General Chemical) Boilers C and 
D (PM and NOX);
    Basin Electric Power Cooperative Laramie River Station Units 1, 2, 
and 3 (PM);
    PacifiCorp Dave Johnston Power Plant Unit 3 (PM);
    PacifiCorp Dave Johnston Power Plant Unit 4 (PM);
    PacifiCorp Jim Bridger Power Plant Units 1, 2, 3, and 4 
(NOX and PM);
    PacifiCorp Naughton Power Plant Unit 3 (PM and NOX);
    PacifiCorp Naughton Power Plant Unit 1 and Unit 2 (PM); and
    PacifiCorp Wyodak Power Plant Unit 1 (PM).
    This section also applies to each owner and operator of the 
following emissions units in the State of Wyoming for which EPA 
proposes to disapprove the State's BART determination and issue a 
NOX BART Federal Implementation Plan:
    Basin Electric Power Cooperative Laramie River Station Units 1, 2, 
and 3;
    PacifiCorp Dave Johnston Power Plant Unit 3;
    PacifiCorp Dave Johnston Power Plant Unit 4;
    PacifiCorp Naughton Power Plant Unit 1 and Unit 2; and
    PacifiCorp Wyodak Power Plant Unit 1.
    This section also applies to each owner and operator of the 
following emissions units in the State of Wyoming for which EPA 
proposes to disapprove the State's reasonable progress determinations 
and issue a reasonable progress determination NOX Federal 
Implementation Plan: PacifiCorp Dave Johnston Power Plant Units 1 and 
2.
    (b) Definitions. Terms not defined below shall have the meaning 
given them in the Clean Air Act or EPA's regulations implementing the 
Clean Air Act. For purposes of this section:
    (1) BART means Best Available Retrofit Technology.
    (2) BART unit means any unit subject to a Regional Haze emission 
limit in Table 1 and Table 2 of this section.
    (3) CAM means Compliance Assurance Monitoring as required by 40 CFR 
part 64.
    (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 NOX emissions, diluent, or stack gas 
volumetric flow rate.
    (5) FIP means Federal Implementation Plan.
    (6) Lb/hr means pounds per hour.
    (7) Lb/MMBtu means pounds per million British thermal units of heat 
input to the fuel-burning unit.
    (8) NOX means nitrogen oxides.
    (9) Operating day means a 24-hour period between 12 midnight and 
the following midnight during which any fuel is combusted at any time 
in the BART or RP unit. It is not necessary for fuel to be combusted 
for the entire 24-hour period.
    (10) The owner/operator means any person who owns or who operates, 
controls, or supervises a unit identified in paragraph (a) of this 
section.
    (11) PM means filterable total particulate matter.
    (12) RP unit means any Reasonable Progress unit subject to a 
Regional Haze emission limit in Table 3 of this section.
    (13) Unit means any of the units identified in paragraph (a) of 
this section.
    (c) Emissions limitations.
    (1) The owners/operators of emissions units subject to this section 
shall not emit, or cause to be emitted, PM or NOX in excess 
of the following limitations:

    Table 1--Emission Limits for BART Units for Which EPA Proposes To
                 Approve the State's BART Determination
------------------------------------------------------------------------
                                            PM Emission    NOX Emission
                                              limits          limits
          Source name/BART unit          -------------------------------
                                             lb/MMBtu        lb/MMBtu
------------------------------------------------------------------------
FMC Westvaco Trona Plant/Unit NS-1A.....            0.05            0.35
FMC Westvaco Trona Plant/Unit NS-1B.....            0.05            0.35
TATA Chemicals Partners (General                    0.09            0.28
 Chemical) Green River Trona Plant/
 Boiler C...............................
TATA Chemicals Partners (General                    0.09            0.28
 Chemical) Green River Trona Plant/
 Boiler D...............................
Basin Electric Power Cooperative Laramie            0.03             N/A
 River Station/Unit 1...................
Basin Electric Power Cooperative Laramie            0.03             N/A
 River Station/Unit 2...................
Basin Electric Power Cooperative Laramie            0.03             N/A
 River Station/Unit 3...................
Pacificorp Dave Johnston Power Plant/              0.015             N/A
 Unit 3.................................
Pacificorp Dave Johnston Power Plant/              0.015             N/A
 Unit 4.................................

[[Page 34792]]

 
Pacificorp Jim Bridger Power Plant/Unit             0.03            0.07
 1......................................
Pacificorp Jim Bridger Power Plant/Unit             0.03            0.07
 2......................................
Pacificorp Jim Bridger Power Plant/Unit             0.03            0.07
 3......................................
Pacificorp Jim Bridger Power Plant/Unit             0.03            0.07
 4......................................
Pacificorp Naughton Power Plant/Unit 1..            0.04             N/A
Pacificorp Naughton Power Plant/Unit 2..            0.04             N/A
Pacificorp Naughton Power Plant/Unit 3..           0.015            0.07
Pacificorp Wyodak Power Plant/Unit 1....           0.015             N/A
------------------------------------------------------------------------

    Table 2--Emission Limits for BART Units for Which EPA Proposes To
      Disapprove the State's BART Determination and Implement a FIP
------------------------------------------------------------------------
                                                           NOX Emission
                  Source name/BART unit                     limit (lb/
                                                              MMBtu)
------------------------------------------------------------------------
Basin Electric Power Cooperative Laramie River Station/             0.07
 Unit 1.................................................
Basin Electric Power Cooperative Laramie River Station/             0.07
 Unit 2.................................................
Basin Electric Power Cooperative Laramie River Station/             0.07
 Unit 3.................................................
Pacificorp Dave Johnston Power Plant/Unit 3.............            0.07
Pacificorp Dave Johnston Power Plant/Unit 4.............            0.12
PacifiCorp Naughton Power Plant/Unit 1..................            0.07
PacifiCorp Naughton Power Plant/Unit 2..................            0.07
Pacificorp Wyodak Power Plant/Unit 1....................            0.17
------------------------------------------------------------------------

     Table 3--Emission Limits for RP Units for Which EPA Proposes To
       Disapprove the State's RP Determination and Implement a FIP
------------------------------------------------------------------------
                                                           NOX Emission
                   Source name/RP unit                      limit (lb/
                                                              MMBtu)
------------------------------------------------------------------------
Pacificorp Dave Johnston Power Plant/Unit 1.............            0.22
Pacificorp Dave Johnston Power Plant/Unit 2.............            0.22
------------------------------------------------------------------------

    (2) These emission limitations shall apply at all times, including 
startups, shutdowns, emergencies, and malfunctions.
    (d) Compliance date.
    (1) The owners and operators of PacifiCorp Jim Bridger Unit 3 and 
Unit 4 shall comply with the emission limitations and other 
requirements of this section by December 31, 2015, for Unit 3 and 
December 31, 2016, for Unit 4.
    (2) The owners and operators of the other BART and RP sources 
subject to this section shall comply with the emissions limitations and 
other requirements of this section within five years of the effective 
date of this rule.
    (e) Compliance determinations for NOX.
    (1) For all BART and RP units other than Trona Plant units:
    (i) CEMS. At all times after the 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 
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) Method.
    (A) For any hour in which fuel is combusted in a unit, the owner/
operator of each unit shall calculate the hourly average NOX 
concentration in lb/MMBtu and lb/hr at the CEMS in accordance with the 
requirements of 40 CFR part 75. At the end of each operating day, the 
owner/operator shall calculate and record a new 30-day rolling average 
emission rate in lb/MMBtu and lb/hr 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) An hourly average NOX emission rate in lb/MMBtu or 
lb/hr 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 (NOX) and the diluent monitor (O2 or 
CO2).
    (C) Compliance with tons-per-year emission limits shall be 
calculated on a rolling 12-month basis. At the end of each calendar 
month, the owner/operator shall calculate and record a new 12-month 
rolling average emission rate from the arithmetic average of all valid 
hourly emission rates from the CEMS for the current month and the 
previous 11 months and the report the result in tons.
    (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.
    (2) For all Trona Plant BART units:
    (i) CEMS. At all times after the compliance date specified in 
paragraph

[[Page 34793]]

(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 60, to accurately measure NOX, diluent, 
and stack gas volumetric flow rate from each unit, including the CEMS 
quality assurance requirements in appendix F of 40 CFR part 60. The 
CEMS shall be used to determine compliance with the emission 
limitations in paragraph (c) of this section for each unit.
    (ii) Method.
    (A) For any hour in which fuel is combusted in a unit, the owner/
operator of each unit shall calculate the hourly average NOX 
concentration in lb/MMBtu and lb/hr at the CEMS in accordance with the 
requirements of 40 CFR part 60. At the end of each operating day, the 
owner/operator shall calculate and record a new 30-day rolling average 
emission rate in lb/MMBtu and lb/hr 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) An hourly average NOX emission rate in lb/MMBtu or 
lb/hr is valid only if the minimum number of data points, as specified 
in 40 CFR part 60, is acquired by both the pollutant concentration 
monitor (NOX) and the diluent monitor (O2 or 
CO2).
    (C) Compliance with tons-per-year emission limits shall be 
calculated on a rolling 12-month basis. At the end of each calendar 
month, the owner/operator shall calculate and record a new 12-month 
rolling average emission rate from the arithmetic average of all valid 
hourly emission rates from the CEMS for the current month and the 
previous 11 months and report results in tons.
    (f) Compliance determinations for particulate matter.
    Compliance with the particulate matter emission limit for each BART 
and RP unit shall be determined from annual performance stack tests. 
Within 60 days of the compliance deadline specified in section (d), and 
on at least an annual basis thereafter, the owner/operator of each unit 
shall conduct a stack test on each unit to measure particulate 
emissions using EPA Method 5, 5B, 5D, or 17, as appropriate, in 40 CFR 
part 60, Appendix A. A test shall consist of three runs, with each run 
at least 120 minutes in duration and each run collecting a minimum 
sample of 60 dry standard cubic feet. Results shall be reported in lb/
MMBtu and lb/hr. In addition to annual stack tests, the owner/operator 
shall monitor particulate emissions for compliance with the BART 
emission limits in accordance with the applicable Compliance Assurance 
Monitoring (CAM) plan developed and approved by the State in accordance 
with 40 CFR part 64.
    (g) Recordkeeping. The owner/operator shall maintain the following 
records for at least five years:
    (1) All CEMS data, including the date, place, and time of sampling 
or measurement; parameters sampled or measured; and results.
    (2) Records of quality assurance and quality control activities for 
emissions measuring systems including, but not limited to, any records 
required by 40 CFR part 75. Or, for Trona Plant units, records of 
quality assurance and quality control activities for emissions 
measuring systems including, but not limited to appendix F of 40 CFR 
part 60.
    (3) Records of all major maintenance activities conducted on 
emission units, air pollution control equipment, and CEMS.
    (4) Any other CEMS records required by 40 CFR part 75. Or, for 
Trona Plant units, any other CEMs records required by 40 CFR part 60.
    (5) Records of all particulate stack test results.
    (6) All data collected pursuant to the CAM plan.
    (h) Reporting. All reports under this section shall be submitted to 
the Director, Office of Enforcement, Compliance and Environmental 
Justice, U.S. Environmental Protection Agency, Region 8, Mail Code 
8ENF-AT, 1595 Wynkoop Street, Denver, Colorado 80202-1129.
    (1) The owner/operator of each unit shall submit quarterly excess 
emissions reports for NOX BART and RP 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. The owner/operator shall also submit 
reports of any exceedances of tons-per-year emission limits.
    (2) The owner/operator of each unit shall submit quarterly CEMS 
performance reports, to include dates and duration of each period 
during which the CEMS was inoperative (except for zero and span 
adjustments and calibration checks), reason(s) why the CEMS was 
inoperative and steps taken to prevent recurrence, and any CEMS repairs 
or adjustments. The owner/operator of each unit shall also submit 
results of any CEMS performance tests required by 40 CFR part 75. Or, 
for Trona Plant units, the owner/operator of each unit shall also 
submit results of any CEMs performance test required appendix F of 40 
CFR part 60 (Relative Accuracy Test Audits, Relative Accuracy Audits, 
and Cylinder Gas Audits).
    (3) When no excess emissions have occurred or the CEMS has not been 
inoperative, repaired, or adjusted during the reporting period, such 
information shall be stated in the quarterly reports required by 
sections (h)(1) and (2) above.
    (4) The owner/operator of each unit shall submit results of any 
particulate matter stack tests conducted for demonstrating compliance 
with the particulate matter BART limits in section (c) above, within 60 
calendar days after completion of the test.
    (5) The owner/operator of each unit shall submit semi-annual 
reports of any excursions under the approved CAM plan in accordance 
with the schedule specified in the source's title V permit.
    (i) Notifications.
    (1) The owner/operator shall submit notification of commencement of 
construction of any equipment which is being constructed to comply with 
the NOX emission limits in paragraph (c) of this section.
    (2) The owner/operator shall submit semi-annual progress reports on 
construction of any such equipment.
    (3) The owner/operator shall submit notification of initial startup 
of any such equipment.
    (j) Equipment operation. At all times, the owner/operator shall 
maintain each unit, including associated air pollution control 
equipment, in a manner consistent with good air pollution control 
practices for minimizing emissions.
    (k) Credible Evidence. Nothing in this section shall preclude the 
use, including the exclusive use, of any credible evidence or 
information, relevant to whether a source would have been in compliance 
with requirements of this section if the appropriate performance or 
compliance test procedures or method had been performed.
0
3. Add section 52.2637 to read as follows:

Sec.  52.2637  Federal implementation plan for reasonable attributable 
visibility impairment long-term strategy.

    As required by 40 CFR 41.306(c), EPA will ensure that the review of 
the State's reasonably attributable visibility

[[Page 34794]]

impairment long-term strategy is coordinated with the regional haze 
long-term strategy under 40 CFR 51.308(g). EPA's review will be in 
accordance with the requirements of 40 CFR 51.306(c).

[FR Doc. 2013-13611 Filed 6-7-13; 8:45 am]
BILLING CODE 6560-50-P
```