Vol. 81 Thursday, 

No. 9 January 14, 2016 

Part II 

Environmental Protection Agency 

40 CFR Part 52 

Approval, Disapproval and Promulgation of Air Quality Implementation 

Plans; Partial Approval and Partial Disapproval of Air Quality 

Implementation Plans and Federal Implementation Plan; Utah; Revisions to 

Regional Haze State Implementation Plan; Federal Implementation Plan for 

Regional Haze; Proposed Rule 

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2004 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R08–OAR–2015–0463; FRL—9939– 

43–Region 8] 

Approval, Disapproval and 

Promulgation of Air Quality 

Implementation Plans; Partial Approval 

and Partial Disapproval of Air Quality 

Implementation Plans and Federal 

Implementation Plan; Utah; Revisions 

to Regional Haze State Implementation 

Plan; Federal Implementation Plan for 

Regional Haze 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to take 

action pursuant to section 110 of the 

Clean Air Act (CAA or Act) on State 

Implementation Plan (SIP) revisions 

submitted by the State of Utah on June 

4, 2015, and October 20, 2015 to 

implement the regional haze program. 

The State’s SIP revisions establish an 

alternative to best available retrofit 

technology (BART) controls that would 

otherwise be required to control 

nitrogen oxides (NOX) at PacifiCorp’s 

Hunter and Huntington power plants. 

The June 2015 SIP revision also 

includes BART determinations for 

particulate matter with an aerodynamic 

diameter of less than 10 micrometers 

(PM10) at these power plants and 

provisions for making the NOX and 

PM10 BART emission limits federally 

enforceable. The CAA requires states to 

prevent any future and remedy any 

existing man-made impairment of 

visibility in national parks and 

wilderness areas designated as Class I 

areas. Air emissions from the four 

electric generating units (EGUs) at the 

two plants affected by this action cause 

or contribute to visibility impairment at 

nine Class I areas including Grand 

Canyon, Arches, Bryce Canyon and Zion 

National Parks. The EPA is issuing two 

co-proposals in order to fully evaluate 

the State’s submittals and the public’s 

input thereon. The EPA would work 

with the State on a revised State plan 

should a partial disapproval and FIP be 

finalized. 

DATES: Comments: Written comments 

must be received on or before March 14, 

2016. 

Public Hearing: A public hearing for 

this proposal is scheduled to be held on 

Tuesday, January 26, 2016, at the Salt 

Lake City Public Library, Main Library, 

from 1 p.m. until 5 p.m., and again from 

6 p.m. until 8 p.m. (local time). 

ADDRESSES: The public hearing will be 

held at the Salt Lake City Public Library, 

Main Library, 210 East 400 South, Salt 

Lake City, Utah 84111. 

Submit your comments, identified by 

Docket ID No. EPA–R08–OAR–2015– 

0463, to the Federal eRulemaking Portal: 

http://www.regulations.gov. Follow the 

online instructions for submitting 

comments. Once submitted, comments 

cannot be edited or removed from 

Regulations.gov. The EPA may publish 

any comment received to its public 

docket. Do not submit electronically any 

information you consider to be 

Confidential Business Information (CBI) 

or other information whose disclosure is 

restricted by statute. Multimedia 

submissions (audio, video, etc.) must be 

accompanied by a written comment. 

The written comment is considered the 

official comment and should include 

discussion of all points you wish to 

make. The EPA will generally not 

consider comments or comment 

contents located outside of the primary 

submission (i.e., on the web, cloud, or 

other file sharing system). For 

additional submission methods, the full 

EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www2.epa.gov/dockets/

commenting-epa-dockets. 

Instructions: Direct your comments to 

Docket ID No. EPA–R08–OAR–2015– 

0463. The EPA’s policy is that all 

comments received will be included in 

the public docket 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 www.regulations.gov 

or email. The 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 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 information 

about EPA’s public docket visit the EPA 

Docket Center homepage at http://www.

epa.gov/epahome/dockets.htm. 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 www.regulations.gov 

index. Although listed in the index, 

some information is not publicly 

available, e.g., CBI or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, will be publicly 

available only in hard copy. Publicly 

available docket materials are available 

either electronically in 

www.regulations.gov or in hard copy at 

the Air Program, Environmental 

Protection Agency (EPA), Region 8, 

1595 Wynkoop Street, Denver, Colorado 

80202–1129. 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 a.m. to 4 p.m., excluding 

federal holidays. 

FOR FURTHER INFORMATION CONTACT: Gail 

Fallon, Air Program, EPA, Region 8, 

Mailcode 8P–AR, 1595 Wynkoop Street, 

Denver, Colorado, 80202–1129, (303) 

312–6281, Fallon.Gail@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Public Hearing 

The public hearing will provide 

interested parties the opportunity to 

present data, views, or arguments 

concerning the proposed action. The 

EPA may ask clarifying questions during 

the oral presentations, but will not 

respond to the presentations at that 

time. Written statements and supporting 

information submitted during the 

comment period will be considered 

with the same weight as oral comments 

and supporting information presented at 

the public hearing. The hearing officer 

may limit the time available for each 

commenter to address the proposal to 5 

minutes or less if the hearing officer 

determines it to be appropriate. The 

limitation is to ensure that everyone 

who wants to make a comment has the 

opportunity to do so. We will not be 

providing equipment for commenters to 

show overhead slides or make 

computerized slide presentations. Any 

person may provide written or oral 

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Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 2005 

comments and data pertaining to our 

proposal at the public hearings. 

Verbatim transcripts, in English, of the 

hearings and written statements will be 

included in the rulemaking docket. 

Table of Contents 

I. General Information 

II. Overview of Proposed Actions 

A. Brief Description of These Co-Proposals 

1. Summary of Proposal To Approve the 

SIP 

2. Summary of Proposal To Partially 

Approve and Partially Disapprove the 

SIP and Propose a FIP 

III. Background and Requirements for 

Regional Haze SIPs and Utah Submittals 

A. Statutory and Regulatory Background 

1. Regional Haze 

2. Requirements of the CAA and EPA’s 

Regional Haze Rule (RHR) 

3. Roles of Agencies in Addressing 

Regional Haze 

4. Development of the Requirements for 40 

CFR 51.309 

5. SIP and FIP Background 

B. Requirements for Regional Haze SIPs 

Applicable to This Proposal 

1. The CAA and the Regional Haze Rule 

2. Determination of Baseline, Natural and 

Current Visibility Conditions 

3. Best Available Retrofit Technology 

4. Monitoring, Recordkeeping and 

Reporting 

5. Consultation With States and Federal 

Land Managers (FLMs) 

C. Requirements for Regional Haze SIPs 

Submitted Under 40 CFR 51.309 

1. Projection of Visibility Improvement 

2. Stationary Source Reductions 

a. Sulfur Dioxide Emission Reductions 

b. Provisions for Stationary Source 

Emissions of Nitrogen Oxides and 

Particulate Matter 

D. General Requirements for PM10 and NOX

Alternative Programs Under the Regional 

Haze Rule and the ‘‘Better-Than-BART 

Demonstration’’ 

E. Summary of State Regional Haze 

Submittals and EPA Actions 

1. 2008 and 2011 Utah RH SIPs 

2. 2012 EPA Action on 2011 and 2008 Utah 

RH SIPs 

3. 2013 Litigation 

4. 2015 Utah RH SIPs 

IV. Utah’s Regional Haze SIP 

A. Summary of Elements Under EPA’s 

Previous Actions Upon Which We Are 

Relying 

1. Affected Class I Areas 

2. BART-Eligible Sources 

3. Sources Subject-to-BART 

B. Summary of Utah’s BART Alternative 

and PM10 BART SIP Revision 

1. Utah BART Alternative 

2. PM10 BART Determinations 

3. Monitoring, Recordkeeping and 

Reporting 

C. Summary of Utah’s Demonstration for 

Alternative Program 

1. A List of All BART-Eligible Sources 

Within the State 

2. A List of All BART-Eligible Sources and 

All BART Source Categories Covered by 

the Alternative Program 

3. Analysis of BART and Associated 

Emission Reductions Achievable 

4. Analysis of Projected Emissions 

Reductions Achievable Through the 

BART Alternative 

5. A Determination That the Alternative 

Achieves Greater Reasonable Progress 

Than Would Be Achieved Through the 

Installation and Operation of BART 

a. Annual Emissions Comparison for 

Visibility-Impairing Pollutants 

b. Improvement in the Number of Days 

With Significant Visibility Impairment 

c. 98th Percentile Impact (dv) 

d. Annual Average Impact (dv) 

e. 90th Percentile Impact (dv) 

f. Timing for the Emissions Reductions 

g. IMPROVE Monitoring Data 

h. Energy and Non-Air Quality Benefits 

i. Cost 

6. Requirement That Emission Reductions 

Take Place During Period of First LongTerm Strategy 

7. Demonstration That Emission 

Reductions From Alternative Program 

Will Be Surplus 

D. Summary of Utah’s Enforceable 

Commitment SIP Revision 

E. Consultation With FLMs 

V. EPA’s Evaluation and Proposed Approval 

of Utah’s Regional Haze SIP 

A. Basis for Proposed Approval 

B. Utah BART Alternative 

1. Summary of Utah BART Alternative 

2. Demonstration of Greater Reasonable 

Progress for the Alternative Program 

a. A List of All BART-Eligible Sources 

Within the State 

b. A List of All BART-Eligible Sources and 

All BART Source Categories Covered by 

the Alternative Program 

c. Analysis of BART and Associated 

Emission Reductions 

d. Analysis of Projected Emissions 

Reductions Achievable Through the 

BART Alternative 

e. A Determination That the Alternative 

Achieves Greater Reasonable Progress 

Than Would Be Achieved Through the 

Installation and Operation of BART 

f. Evaluation of the Weight of Evidence 

g. Requirement That Emission Reductions 

Take Place During Period of First LongTerm Strategy 

h. Demonstration That Emission 

Reductions From Alternative Program 

Will Be Surplus 

C. PM10 BART Determinations 

D. Monitoring, Recordkeeping, and 

Reporting 

E. Consultation With FLMs 

VI. EPA’s Evaluation and Proposed Partial 

Approval and Partial Disapproval of 

Utah’s Regional Haze SIP 

A. Basis for Proposed Partial Disapproval 

and Partial Approval 

B. Utah BART Alternative 

1. Summary of Utah BART Alternative 

2. Demonstration of Greater Reasonable 

Progress for Alternative Program 

a. A List of All BART-Eligible Sources 

Within the State 

b. A List of All BART-Eligible Sources and 

All BART Source Categories Covered by 

the Alternative Program 

c. Analysis of BART and Associated 

Emission Reductions Achievable 

d. Analysis of Projected Emissions 

Reductions Achievable Through the 

BART Alternative 

e. A Determination That the Alternative 

Achieves Greater Reasonable Progress 

Than Would Be Achieved Through the 

Installation and Operation of BART 

f. Evaluation of the Weight of Evidence 

g. Evaluation That Emission Reductions 

Take Place During Period of First LongTerm Strategy 

h. Demonstration That Emission 

Reductions From Alternative Program 

Will Be Surplus 

C. Monitoring, Recordkeeping and 

Reporting for Utah’s BART Alternative 

D. Proposed Federal Implementation Plan 

1. BART Evaluations 

a. Costs of Compliance 

b. Visibility Impact Modeling 

2. Hunter Power Plant 

a. Hunter Unit 1 

b. Hunter Unit 2 

3. Huntington Power Plant 

a. Huntington Unit 1 

b. Huntington Unit 2 

4. Federal Monitoring, Recordkeeping, and 

Reporting 

E. PM10 BART Determinations 

F. Consultation With FLMs 

VII. EPA’s Proposed Actions 

A. Proposed Approval 

B. Proposed Partial Disapproval/Approval 

and Federal Implementation Plan 

VIII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

(UMRA) 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and 

Advancement Act 

J. Executive Order 12898: Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations 

I. General Information 

What should I consider as I prepare my 

comments for EPA? 

1. Submitting Confidential Business 

Information (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 on a disk or 

CD–ROM that you mail to EPA, mark 

the outside of the disk or CD–ROM as 

CBI and then identify electronically 

within the disk or CD ROM the specific 

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2006 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

1Our proposed approval for one element, 

reporting for PM BART limits, is a conditional 

approval based on a commitment from Utah to 

provide a SIP revision to address this element. See 

section V.D of this document for a more detailed 

explanation. 

2 In March 2015, conservation groups sued EPA 

in the U.S. District Court for the District of Colorado 

alleging that EPA failed to promulgate a regional 

haze FIP for Utah within the two-year period 

allowed by CAA section 110(c). See Wildearth 

Guardians v. McCarthy, Case No. 1:15–cv–oo630– 

MSK–KLM, at *1–2 (D. Colo. Mar. 27, 2015). EPA 

entered into a consent decree resolving this dispute 

requiring EPA to sign notices of proposed and final 

rulemaking for the regional haze requirements for 

Utah by December 16, 2015 and June 1, 2016, 

respectively. The signing of this proposed rule 

partially fulfills EPA’s obligations under the 

consent decree. See id. (Doc. 60, Motion to Enter 

Consent Decree filed on December 8, 2015). 

3 40 CFR 51.308(e)(2)(i). 

4 40 CFR 51.308(e)(2)(iii). 

5 40 CFR 51.308(e)(2)(iv). 

6 40 CFR 51.308(e)(2)(i)(E); 40 CFR 51.308(e)(3). 

7 71 FR 60612, 60621 (Oct. 13, 2006). 

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: 

• Identify the rulemaking by docket 

number and other identifying 

information (subject heading, Federal 

Register, date, and page number); 

• Follow directions and organize your 

comments; 

• Explain why you agree or disagree; 

• Suggest alternatives and substitute 

language for your requested changes; 

• Describe any assumptions and 

provide any technical information and/ 

or data that you used; 

• If you estimate potential costs or 

burdens, explain how you arrived at 

your estimate in sufficient detail to 

allow for it to be reproduced; 

• Provide specific examples to 

illustrate your concerns, and suggest 

alternatives; 

• Explain your views as clearly as 

possible, avoiding the use of profanity 

or personal threats; and 

• Make sure to submit your 

comments by the comment period 

deadline identified. 

II. Overview of Proposed Actions 

The State of Utah submitted SIP 

revisions on June 4, 2015, and October 

20, 2015, to fulfill the CAA requirement 

to meet the requirements for the Best 

Available Retrofit Technology (BART) 

in the Regional Haze Rule (RHR) for the 

pollutants NOX and PM10. As described 

more fully in Section III, the purpose of 

the RHR is to remedy and prevent 

impairment of visibility in Class I areas 

resulting from anthropogenic air 

pollution. Instead of establishing BART 

controls for NOX, Utah’s SIP revisions 

contain an alternative to BART. The 

revisions also include BART controls for 

PM10. The idea of a BART alternative, 

which can take into account (and even 

encourage) plans that take into account 

state specific situations is a reasonable 

one, and one EPA supports where 

consistent with the CAA and RHR. 

The State’s SIP contains a NOX BART 

Alternative and metrics to evaluate the 

BART Alternative. In light of the variety 

of metrics Utah used, this is a 

complicated analysis and EPA 

considered the State’s BART Alternative 

in the context of other previous 

decisions we and the states have made. 

EPA carefully analyzed the SIP 

revisions and the supporting 

information submitted by the State. We 

also conducted additional analyses, 

which are included with this proposal. 

Based on a careful consideration of all 

of this information, EPA is proposing 

and soliciting comments on two 

different actions: A proposal to approve 

the State SIP in its entirety,1 and a 

proposal to partially approve and 

partially disapprove the State SIP and 

propose a FIP.2 EPA takes seriously its 

decision to co-propose these two actions 

(disapprove part of the State’s plan, 

alongside proposing to approve it), as it 

is preferable that the regional haze 

program be implemented through state 

plans. As part of its oversight 

responsibilities, EPA must be able to 

find that the state plan is consistent 

with the requirements of the Act. In this 

instance, we developed analyses and 

rationale supporting both a proposed 

approval and a proposed partial 

approval and partial disapproval, and 

we solicit input on each proposal. EPA 

intends to finalize only one proposal, 

although the details of our final action 

may differ somewhat from what is 

presented here based on any comments 

and additional information we receive. 

Deciding whether to approve the State 

SIP entails an evaluation of Utah’s SIP 

revision with respect to three elements 

in the RHR: (1) ‘‘[a] demonstration that 

the emissions trading program or other 

alternative measure will achieve greater 

reasonable progress than would have 

resulted from the installation and 

operation of BART at all sources subject 

to BART in the State and covered by the 

alternative program’’; 3 (2) ‘‘[a] 

requirement that all necessary emission 

reductions take place during the period 

of the first long-term strategy for 

regional haze’’; 4 and (3) ‘‘[a] 

demonstration that the emissions 

reductions resulting from the alternative 

measure will be surplus to those 

reductions resulting from measures 

adopted to meet requirements of the 

CAA as of the baseline date of the 

SIP.’’ 5

For the first element, the 

determination that the alternative 

measure will achieve greater reasonable 

progress than BART, the State must 

provide the following: (1) A list of all 

BART-eligible sources within the State; 

(2) a list of all BART-eligible sources 

and all BART source categories covered 

by the alternative program; (3) an 

analysis of BART and associated 

emission reductions; (4) an analysis of 

the projected emission reductions 

achievable through the BART 

alternative; and (5) a determination that 

the alternative achieves greater 

reasonable progress than would be 

achievable through the installation and 

operation of BART. A State has several 

options for making the greater 

reasonable progress determination; 6 in 

this instance, the State elected to use 

two separate approaches. 

EPA’s evaluation of the BART 

Alternative therefore entails 

consideration of both of the State’s 

analyses. As described in our 2006 

revisions to the RHR, concerning BART 

alternatives, ‘‘[t]he State’s discretion in 

this area is subject to the condition that 

it must be reasonably exercised and that 

its decisions be supported by adequate 

documentation of its analyses.’’ 7 As 

presented in section V, several of the 

metrics in the State’s analyses appear to 

support a determination that a BART 

Alternative presented by the State 

achieves greater reasonable progress 

than BART. However, several other 

metrics in the State’s analyses do not 

appear to support a conclusion that the 

BART Alternative achieves greater 

reasonable progress. The complexity of 

our evaluation leads us to propose and 

solicit comment on two conclusions and 

courses of action: (1) The State’s 

submittal meets the test above and we 

approve the BART Alternative; or (2) the 

State’s submittal falls short of meeting 

this test and we disapprove the BART 

Alternative and promulgate a FIP for 

NOX BART. We request comment on all 

aspects of each proposal. 

Given the complexities in evaluating 

these co-proposals, EPA wants to ensure 

that our final decision is based on the 

best and most currently available data 

and information, and is taken with the 

fullest possible consideration of public 

input. Therefore, in addition to seeking 

comments on the co-proposals, we are 

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8 Visual range is the greatest distance, in 

kilometers or miles, at which a dark object can be 

viewed against the sky. 

9 64 FR 35715, 35716 (July 1, 1999). 

10 Id. 

11 42 U.S.C. 7491(a). Areas designated as 

mandatory Class I Federal areas consist of national 

parks exceeding 6000 acres, wilderness areas and 

national memorial parks exceeding 5000 acres, and 

all international parks that were in existence on 

August 7, 1977. 42 U.S.C. 7472(a). In accordance 

with section 169A of the CAA, EPA, in consultation 

with the Department of Interior, promulgated a list 

of 156 areas where visibility is identified as an 

important value. 44 FR 69122 (Nov. 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 section, 

we mean a ‘‘mandatory Class I Federal area.’’ 

also asking if interested parties have 

additional information or analysis on 

the co-proposals, for example, analysis 

related to the modeled visibility benefits 

of the BART Alternative compared to 

BART. In light of any such information, 

we are asking whether interested parties 

think the Agency should consider BART 

Alternatives or BART control 

technology options that are related to 

what we propose and that could be 

finalized as our FIP (if we disapprove 

the Utah SIP submittal in our final 

action). The Agency is also asking if 

interested parties have additional 

information or comments on the 

proposed timing of compliance. 

The Agency will take the comments 

and testimony received, as well as any 

further SIP revisions received from the 

State prior to our final action, into 

consideration in our final promulgation. 

As noted above, additional information 

and comments may lead the Agency to 

adopt final SIP and/or FIP regulations 

that differ somewhat from the coproposals presented here regarding the 

BART Alternative, BART control 

technology option or emission limits, or 

impact other proposed regulatory 

provisions. EPA’s final action will fully 

consider these complex issues and the 

comments received, which will result in 

the selection of a final action that meets 

the CAA and regulatory requirements 

requiring development and 

implementation of plans to ensure 

reasonable progress toward improving 

visibility in mandatory Class I areas by 

reducing emissions that cause or 

contribute to regional haze. 

A. Brief Description of These CoProposals 

1. Summary of Proposal To Approve the 

SIP 

As explained more fully later, we are 

proposing to approve these aspects of 

the State’s June 4, 2015 SIP submittal: 

• NOX BART Alternative, including 

NOX emission reductions from Hunter 

Units 1, 2, and 3, Huntington Units 1 

and 2, and Carbon Units 1 and 2, and 

sulfur dioxide (SO2) and PM10 emission 

reductions from Carbon Units 1 and 2. 

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2 

and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for units subject 

to the BART Alternative and the PM10

emission limits. 

We are proposing to approve these 

elements of the State’s October 20, 2015 

SIP submittal: 

• Enforceable commitments to revise 

SIP section XX.D.3.c and state rule 

R307–150 by March 2018 to clarify 

emission inventory requirements for 

tracking compliance with the SO2

milestone and properly accounting for 

the SO2 emission reductions due to the 

closure of the Carbon plant. 

2. Summary of Proposal to Partially 

Approve and Partially Disapprove the 

SIP and Propose a FIP 

We are proposing to approve these 

elements of the State’s SIP submittals: 

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2, 

and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for units subject 

to the PM10 emission limits. 

We are proposing to disapprove these 

aspects of the State’s June 4, 2015 SIP: 

• NOX BART Alternative, including 

NOX emission reductions from Hunter 

Units 1, 2, and 3, Huntington Units 1 

and 2, and Carbon Units 1 and 2, and 

SO2 and PM10 emission reductions from 

Carbon Units 1 and 2. 

We are proposing to disapprove the 

State’s October 20, 2015 SIP submittal. 

We are proposing promulgation of a 

FIP to address the deficiencies in the 

Utah regional haze SIPs that are 

identified in this notice. The proposed 

FIP includes the following elements: 

• NOX BART determinations and 

emission limits for Hunter Units 1 and 

2 and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for NOX at 

Hunter Units 1 and 2, and Huntington 

Units 1 and 2. 

If we partially disapprove the SIP, and 

promulgate a FIP, the State may submit 

a SIP revision to supersede the FIP. If 

we determine that the SIP revision is 

approvable, regardless of whether or not 

its terms match those of our final FIP, 

we would propose to approve such a 

SIP revision. If we issue a final FIP, we 

encourage the State to submit a SIP 

revision to replace the FIP. 

III. Background and Requirements for 

Regional Haze SIPs and Utah 

Submittals 

A. Statutory and Regulatory Background 

1. Regional Haze 

Regional haze is visibility impairment 

that is produced by numerous sources 

that 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., 

SO2, NOX, and in some cases, ammonia 

(NH3) and volatile organic compounds 

(VOC)). Coarse PM also impairs 

visibility. 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. Coarse 

PM also can cause adverse health 

effects. 

Data from the existing visibility 

monitoring network, the ‘‘Interagency 

Monitoring of Protected Visual 

Environments’’ (IMPROVE) monitoring 

network, show that at the time the 

regional haze rule was finalized in 1999, 

visibility impairment caused by air 

pollution occurred virtually all the time 

at most national parks and wilderness 

areas. The average visual range 8 in 

many Class I areas (i.e., national parks, 

wilderness areas, and international 

parks meeting certain size criteria) in 

the western U.S. was 62–93 miles, but 

in some Class I areas, these visual 

ranges may have been impacted by 

natural wildfire and dust episodes.9 In 

most of the eastern Class I areas of the 

U.S., the average visual range was less 

than 19 miles, ‘‘or about one-fifth of the 

visual range that would exist under 

estimated natural conditions.’’ 10

2. 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 which impairment results from 

manmade air pollution.’’ 11 On 

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12 45 FR 80084, 80084 (Dec. 2, 1980). 13 64 FR 35714, 35714 (July 1, 1999) (codified at 

40 CFR part 51, subpart P). 14EPA’s RHR requires subsequent updates to the 

regional haze SIPs. 40 CFR 51.308(g) through (i). 15 42 U.S.C. 7410(c)(1). 

16The Colorado Plateau is a high, semi-arid 

tableland in southeast Utah, northern Arizona, 

northwest New Mexico, and western Colorado. The 

16 mandatory Class I areas are as follows: Grand 

Canyon National Park, Mount Baldy Wilderness, 

Petrified Forest National Park, Sycamore Canyon 

Wilderness, Black Canyon of the Gunnison National 

Park Wilderness, Flat Tops Wilderness, Maroon 

Bells Wilderness, Mesa Verde National Park, 

Weminuche Wilderness, West Elk Wilderness, San 

Pedro Parks Wilderness, Arches National Park, 

Bryce Canyon National Park, Canyonlands National 

Park, Capital Reef National Park, and Zion National 

Park. 

17 64 FR 35714, 35749 (July 1, 1999). 18 64 FR 35714, 35749, 35756. 

December 2, 1980, EPA promulgated 

regulations to address visibility 

impairment in Class I areas that are 

‘‘reasonably attributable’’ to a single 

source or small group of sources, i.e., 

reasonably attributable visibility 

impairment.12 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. 

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, 1999.13

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 through 

309. Some of the main elements of the 

regional haze requirements are 

summarized later in section III.C 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, 

2007.14

Once EPA 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.15

3. Roles of Agencies in Addressing 

Regional Haze 

Successful implementation of the 

regional haze program requires longterm regional coordination among 

states, tribal governments, and various 

federal agencies. As noted previously, 

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 

created 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. 

4. Development of the Requirements for 

40 CFR 51.309 

EPA’s RHR provides two paths to 

address regional haze. One is 40 CFR 

51.308, requiring states to perform 

individual point source BART 

determinations and evaluate the need 

for other control strategies. These 

strategies must be shown to make 

‘‘reasonable progress’’ in improving 

visibility in Class I areas inside the state 

and in neighboring jurisdictions. The 

other method for addressing regional 

haze is through 40 CFR 51.309, and is 

an option for nine states termed the 

‘‘Transport Region States,’’ which 

include: Arizona, California, Colorado, 

Idaho, Nevada, New Mexico, Oregon, 

Utah, and Wyoming. By meeting the 

requirements under 40 CFR 51.309, 

states can be deemed to be making 

reasonable progress toward the national 

goal of achieving natural visibility 

conditions for the 16 Class I areas on the 

Colorado Plateau. 

Section 309 requires participating 

states to adopt regional haze strategies 

that are based on recommendations 

from the Grand Canyon Visibility 

Transport Commission (GCVTC) for 

protecting the 16 Class I areas on the 

Colorado Plateau.16 The EPA 

established the GCVTC on November 

13, 1991. The purpose of the GCVTC 

was to assess information about the 

adverse impacts on visibility in and 

around the 16 Class I areas on the 

Colorado Plateau and to provide policy 

recommendations to EPA to address 

such impacts. Section 169B of the CAA 

called for the GCVTC to evaluate 

visibility research, as well as other 

available information, pertaining to 

adverse impacts on visibility from 

potential or projected growth in 

emissions from sources located in the 

region. The GCVTC determined that all 

Transport Region States could 

potentially impact the Class I areas on 

the Colorado Plateau. The GCVTC 

submitted a report to EPA in 1996 with 

its policy recommendations for 

protecting visibility for the Class I areas 

on the Colorado Plateau. Provisions of 

the 1996 GCVTC report include: 

Strategies for addressing smoke 

emissions from wildland fires and 

agricultural burning; provisions to 

prevent pollution by encouraging 

renewable energy development; and 

provisions to manage clean air corridors 

(CACs), mobile sources, and windblown dust, among other things. The 

EPA codified these recommendations as 

an option available to states as part of 

the 1999 RHR.17

EPA determined that the GCVTC 

strategies would provide for reasonable 

progress in mitigating regional haze if 

supplemented by an annex containing 

quantitative emission reduction 

milestones and provisions for a trading 

program or other alternative measure.18

Thus, the 1999 RHR required that 

western states submit an annex to the 

GCVTC report with quantitative 

milestones and detailed guidelines for 

an alternative program in order to 

establish the GCVTC recommendations 

as an alternative approach to fulfilling 

the section 308 requirements for 

compliance with the RHR. In September 

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19 68 FR 33764, 33767 (June 5, 2003). 

20Ctr. for Energy & Econ. Dev. v. EPA, 398 F.3d 

653, 654 (D.C. Cir. 2005). 

21 71 FR 60612, 60612 (Oct. 13, 2006). 

22 42 U.S.C. 7410(a), 7491, and 7492(a), 169A, and 

169B. 

23 42 U.S.C. 7410(c)(1). 

24See 70 FR 39104, 39118 (July 6, 2005). 

25The preamble to the RHR provides additional 

details about the deciview (dv) scale. 64 FR 35714, 

35725 (July 1, 1999). 

26 40 CFR 81.401–437. 

27 Guidance for Estimating Natural Visibility 

Conditions Under the Regional Haze Rule, EPA– 

454/B–03–005, available at http://www3.epa.gov/

ttn/caaa/t1/memoranda/rh_envcurhr_gd.pdf, 

(hereinafter referred to as ‘‘our 2003 Natural 

Visibility Guidance’’) (Sept. 2003) (documents 

identified with Internet addresses are available in 

the docket) ; Guidance for Tracking Progress Under 

the Regional Haze Rule, EPA–454/B–03–004, 

available at http://www3.epa.gov/ttnamti1/files/

ambient/visible/tracking.pdf (hereinafter referred to 

as our ‘‘2003 Tracking Progress Guidance’’) (Sept. 

2003). 

28 ‘‘Natural Haze Levels II: Application of the 

New IMPROVE Algorithm to Natural Species 

Concentrations Estimates’’, Final Report by the 

Natural Haze Levels II Committee to the RPO 

Monitoring/Data Analysis Workgroup, power point 

presentation included in the docket. 

2000, the WRAP, which is the successor 

organization to the GCVTC, submitted 

an annex to EPA. The annex contained 

SO2 emissions reduction milestones and 

detailed provisions of a backstop trading 

program to be implemented 

automatically if voluntary measures 

failed to achieve the SO2 milestones. 

EPA codified the annex on June 5, 2003 

at 40 CFR 51.309(h).19

Five western states, including Utah, 

submitted implementation plans under 

section 309 in 2003. EPA was 

challenged by the Center for Energy and 

Economic Development (CEED) on the 

validity of the annex provisions. In 

CEED v. EPA, the DC Circuit Court of 

Appeals vacated EPA approval of the 

WRAP annex.20 In response to the 

court’s decision, EPA vacated the annex 

requirements adopted under 40 CFR 

51.309(h), but left in place the stationary 

source requirements in 40 CFR 

51.309(d)(4).21 The requirements under 

40 CFR 51.309(d)(4) contain general 

requirements pertaining to stationary 

sources and market trading, and allow 

states to adopt alternatives to the point 

source application of BART. 

5. SIP and FIP Background 

The CAA requires each state to 

develop plans to meet various air 

quality requirements, including 

protection of visibility.22 The plans 

developed by a state are referred to as 

SIPs. A state must submit its SIPs and 

SIP revisions to EPA for approval. Once 

approved, a SIP is enforceable by EPA 

and citizens under the CAA, which is 

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 not approvable, then we 

must promulgate a FIP to fill this 

regulatory gap.23 As discussed 

elsewhere in this preamble, one of the 

proposals would disapprove aspects of 

Utah’s regional haze SIP and promulgate 

a FIP to address the deficiencies in 

Utah’s regional haze SIP, should we 

disapprove the SIP in our final action. 

B. Requirements for Regional Haze SIPs 

Applicable to This Proposal 

1. 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 later on. 

2. Determination of Baseline, Natural, 

and Current Visibility Conditions 

The RHR establishes the deciview 

(dv) as the principal metric or unit for 

expressing visibility.24 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 dv is a more useful measure for 

tracking progress in improving visibility 

than light extinction itself because each 

dv change is an equal incremental 

change in visibility perceived by the 

human eye. Most people can detect a 

change in visibility at one dv.25

The dv is used in expressing 

reasonable progress goals (RPGs, which 

are interim visibility goals towards 

meeting the national visibility goal), in 

defining baseline, current, and natural 

conditions; and in 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 

emissions that cause or contribute to 

regional haze. The national goal is a 

return to natural conditions, i.e. to reach 

a state at which anthropogenic sources 

of air pollution 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,26 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 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 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. In 2003, EPA 

provided guidance to states regarding 

how to calculate baseline, natural and 

current visibility conditions.27

Subsequently, the Natural Haze Levels II 

Committee developed updated estimates 

of natural haze for average natural 

conditions and for the averages of the 

best 20% and worst 20% natural 

condition days 28 that have been used by 

states and EPA in visibility assessments. 

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 five-year 

averages of the degree of visibility 

impairment for the 20 percent least 

impaired days and the 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 

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29See 42 U.S.C. 7491(g)(7) (listing the set of 

‘‘major stationary sources’’ potentially subject-toBART). 

30 70 FR 39104, 39104 (July 6, 2005). 

31BART-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. 

32 42 U.S.C. 7491(b)(2)(A). 

33 40 CFR part 51, appendix Y, § III.A.1. 

34 42 U.S.C. 7491(g)(4); 40 CFR 51.308(e)(1)(iv). 

35 40 CFR 51.212(a). 

36 40 CFR 51.211. 

37 40 CFR 51.308(i). 

amount of progress made. In general, the 

2000–2004 baseline period is 

considered the time from which 

improvement in visibility is measured. 

3. 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 29 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. 

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.30 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 that meet 

the definition of ‘‘BART-eligible source’’ 

set forth in 40 CFR 51.301; 31 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’’ 32 (a source 

that fits this description is ‘‘subject-toBART’’); and third, for each source 

subject-to-BART, states then identify the 

best available type and level of control 

for reducing emissions. 

States must address all visibilityimpairing 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 compounds 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 dv.33

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 

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.34 As noted 

previously, 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. 

4. Monitoring, Recordkeeping and 

Reporting 

The CAA requires that SIPs, including 

the regional haze SIP, contain elements 

sufficient to ensure emission limits are 

practically enforceable. CAA section 

110(a)(2) requires in part that the 

monitoring, recordkeeping and 

reporting (MRR) provisions of states’ 

SIPs must include enforceable emission 

limitations, control measures, and 

compliance timeframes. It also requires 

SIPs to provide for enforcement of these 

measures, installation, maintenance, 

and replacement of equipment, 

emissions monitoring, periodic 

emissions reports and availability of 

emissions reports for public inspection. 

Accordingly, 40 CFR part 51, subpart 

K, Source Surveillance, requires the SIP 

to provide for monitoring the status of 

compliance with the regulations in it, 

including ‘‘[p]eriodic testing and 

inspection of stationary sources,’’ 35 and 

‘‘legally enforceable procedures’’ for 

recordkeeping and reporting.36

Furthermore, 40 CFR part 51, appendix 

V, Criteria for Determining the 

Completeness of Plan Submissions, 

states in section 2.2 that complete SIPs 

contain: ‘‘(g) Evidence that the plan 

contains emission limitations, work 

practice standards and recordkeeping/

reporting requirements, where 

necessary, to ensure emission levels’’; 

and ‘‘(h) Compliance/enforcement 

strategies, including how compliance 

will be determined in practice.’’ 

5. Consultation With States and Federal 

Land Managers (FLMs) 

The RHR requires that states consult 

with FLMs before adopting and 

submitting their SIPs.37 States must 

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38Utah addressed some of the requirements of 40 

CFR 51.309 in 2008 and 2011 SIP submissions. EPA 

took final action on some of the provisions in the 

2008 and 2011 SIP submissions in earlier notices. 

See 40 CFR 51.309 for a complete listing of the 

regulations under which the 2008 and 2011 SIP 

submissions were evaluated. 

39 40 CFR 51.309(d)(2). 

40 40 CFR 51.309(d)(4). 41 40 CFR 51.309(d)(4)(v). 

provide FLMs an opportunity for 

consultation, in person and at least 60 

days prior to holding any public hearing 

on the SIP. This consultation must 

include the opportunity for the FLMs to 

discuss their assessments 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. 

C. Requirements for Regional Haze SIPs 

Submitted Under 40 CFR 51.309 

The following is a summary and basic 

explanation of the regulations covered 

under section 51.309 of the RHR that are 

addressed in this notice.38

1. Projection of Visibility Improvement 

For each of the 16 Class I areas 

located on the Colorado Plateau, the SIP 

must include a projection of the 

improvement in visibility expressed in 

deciviews.39 An explanation of the 

deciview metric is provided in section 

III.C.2. States need to show the 

projected visibility improvement for the 

best and worst 20 percent days through 

the year 2018, based on the application 

of all section 309 control strategies. 

2. Stationary Source Reductions 

a. Sulfur Dioxide Emission Reductions 

Rather than requiring source-specific 

BART controls as explained previously 

in section III.C.4, states have the 

flexibility to adopt an emissions trading 

program or other alternative program as 

long as the alternative provides greater 

reasonable progress than would be 

achieved by the application of BART 

pursuant to 40 CFR 51.308(e)(2). Under 

40 CFR 51.309, states can satisfy the SO2

BART requirements by adopting SO2

emission milestones and a backstop 

trading program.40 Under this approach, 

states must establish declining SO2

emission milestones for each year of the 

program through 2018. The milestones 

must be consistent with the GCVTC’s 

goal of 50 to 70 percent reduction in 

SO2 emissions by 2040. 

Pursuant to 40 CFR 51.309(d)(4)(ii) 

through (iv), states must include 

requirements in the SIP that allow states 

to determine whether the milestone has 

been exceeded. These requirements 

include documentation of the baseline 

emission calculation, monitoring, 

recordkeeping, and reporting of SO2

emissions, and provisions for 

conducting an annual evaluation to 

determine whether the milestone has 

been exceeded. SIPs must also contain 

requirements for implementing the 

backstop trading program in the event 

that the milestone is exceeded and the 

program is triggered.41

The WRAP, in conjunction with EPA, 

developed a model for a backstop 

trading program. In order to ensure 

consistency between states, states opting 

to participate in the 309 program 

needed to adopt rules that are 

substantively equivalent to the model 

rules for the backstop trading program 

to meet the requirements of 40 CFR 

51.309(d)(4). The trading program must 

also be implemented no later than 15 

months after the end of the first year 

that the milestone is exceeded, require 

that sources hold allowances to cover 

their emissions, and provide a 

framework, including financial 

penalties, to ensure that the 2018 

milestone is met. 

b. Provisions for Stationary Source 

Emissions of Nitrogen Oxides and 

Particulate Matter 

Pursuant to 40 CFR 51.309(d)(4)(vii), 

a section 309 SIP must contain any 

necessary long term strategies and 

BART requirements for PM and NOX. 

These requirements, including the 

process for conducting BART 

determinations either based on the 

consideration of the five statutory 

factors or based on an alternative 

program, are explained previously in 

section III.C.4 and in section III.E, 

respectively. 

D. General Requirements for PM10 and 

NOX Alternative Programs Under the 

Regional Haze Rule and the ‘‘BetterThan-BART Demonstration’’ 

States opting to submit an alternative 

program must meet requirements under 

40 CFR 51.308(e)(2) and (e)(3). These 

requirements for alternative programs 

relate to the ‘‘better-than-BART’’ test 

and fundamental elements of any 

alternative program. 

In order to demonstrate that the 

alternative program achieves greater 

reasonable progress than source-specific 

BART, a state must demonstrate that its 

SIP meets the requirements in 40 CFR 

51.308(e)(2)(i) through (v). States 

submitting section 309 SIPs or other 

alternative programs are required to list 

all BART-eligible sources and categories 

covered by the alternative program. 

States are then required to determine 

which BART-eligible sources are 

‘‘subject-to-BART.’’ The SIP must 

provide an analysis of the best system 

of continuous emission control 

technology available and the associated 

reductions for each source subject-toBART covered by the alternative 

program, or what is termed a ‘‘BART 

benchmark.’’ Where the alternative 

program has been designed to meet 

requirements other than BART, states 

may use simplifying assumptions in 

establishing a BART benchmark. 

Pursuant to 40 CFR 51.308(e)(2)(i)(E), 

the State must also provide a 

determination that the alternative 

program achieves greater reasonable 

progress than BART under 40 CFR 

51.308(e)(3) or otherwise based on the 

clear weight of evidence. 40 CFR 

51.308(e)(3), in turn, provides a specific 

test for determining whether the 

alternative achieves greater reasonable 

progress than BART. If the distribution 

of emissions for the alternative program 

is not substantially different than for 

BART, and the alternative program 

results in greater emission reductions, 

then the alternative program may be 

deemed to achieve greater reasonable 

progress. If the distribution of emissions 

is significantly different, the differences 

in visibility between BART and the 

alternative program, must be 

determined by conducting dispersion 

modeling for each impacted Class I area 

for the best and worst 20 percent of 

days. The modeling would demonstrate 

‘‘greater reasonable progress’’ if both of 

the two following criteria are met: (1) 

Visibility does not decline in any Class 

I area, and (2) there is overall 

improvement in visibility when 

comparing the average differences 

between BART and the alternative 

program over all of the affected Class I 

areas. 

Alternately, pursuant to 40 CFR 

51.308(e)(2) States may show that the 

BART alternative achieves greater 

reasonable progress than the BART 

benchmark ‘‘based on the clear weight 

of evidence’’ determinations, which 

‘‘attempt to make use of all available 

information and data which can inform a 

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2012 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

42 71 FR 60612, 60622 (Oct. 13, 2006). 

43 71 FR 60612, 60621. 

44 77 FR 74355, 74357 (Dec. 14, 2012). 

45 Id. 

46 78 FR 4071, 4072 (Jan. 18, 2013). 

47Wildearth Guardians v. United States EPA, 728 

F.3d 1075, 1083–84 (10th Cir. 2013). 

decision while recognizing the relative 

strengths and weaknesses of that information 

in arriving at the soundest decision possible. 

Factors which can be used in a weight of 

evidence determination in this context may 

include, but not be limited to, future 

projected emissions levels under the program 

as compared to under BART, future projected 

visibility conditions under the two scenarios, 

the geographic distribution of sources likely 

to reduce or increase emissions under the 

program as compared to BART sources, 

monitoring data and emissions inventories, 

and sensitivity analyses of any models used. 

This array of information and other relevant 

data may be of sufficient quality to inform 

the comparison of visibility impacts between 

BART and the alternative program. In 

showing that an alternative program is better 

than BART and when there is confidence that 

the difference in visibility impacts between 

BART and the alternative scenarios are 

expected to be large enough, a weight of 

evidence comparison may be warranted in 

making the comparison. The EPA will 

carefully consider the evidence before us in 

evaluating any SIPs submitted by States 

employing such an approach.’’ 42

Finally, in promulgating the final 

regional haze program requirements and 

responding to concerns regarding 

‘‘impermissibly vague’’ language in 

§ 51.308(e)(3) that would allow a State 

to ‘‘approve alternative measures that 

are less protective than BART,’’ we 

explained that ‘‘[t]he State’s discretion 

in this area is subject to the condition 

that it must be reasonably exercised and 

that its decisions be supported by 

adequate documentation of its 

analyses.’’ 43

Under 40 CFR 51.308(e)(2)(iii) and 

(iv), all emission reductions for the 

alternative program must take place by 

2018, and all the emission reductions 

resulting from the alternative program 

must be surplus to those reductions 

resulting from measures adopted to 

meet requirements of the CAA as of the 

baseline date of the SIP. Pursuant to 40 

CFR 51.309(e)(2)(v), states have the 

option of including a provision that the 

emissions trading program or other 

alternative measure include a 

geographic enhancement to the program 

to address the requirement under 40 

CFR 51.302(c) related to BART for 

reasonably attributable visibility 

impairment from the pollutants covered 

under the emissions trading program or 

other alternative measure. 

E. Summary of State Regional Haze 

Submittals and EPA Actions 

1. 2008 and 2011 Utah RH SIPs 

On May 26, 2011, the Governor of the 

State of Utah submitted to EPA a 

Regional Haze SIP under 40 CFR 51.309 

of the RHR (‘‘2011 Utah RH SIP’’). This 

submittal included BART 

determinations for NOX and PM10 at 

Utah’s four subject-to-BART sources: 

PacifiCorp’s Hunter Units 1 and 2 and 

Huntington Units 1 and 2. All four units 

are tangentially fired fossil fuel fired 

EGUs each with a net generating 

capacity of 430 MW, permitted to burn 

bituminous coal. This submittal also 

included a backstop trading program 

under 40 CFR 51.309 intended to meet 

the requirement for controlling SO2 by 

establishing a cap on emissions. The 

trading program covers Utah, Wyoming, 

New Mexico and the City of 

Albuquerque. 

Utah also submitted SIPs on 

December 12, 2003, August 8, 2004 and 

September 9, 2008, to meet the 

requirements of the RHR. These 

submittals were, for the most part, 

superseded and replaced by the May 26, 

2011 submittal as further explained in 

the next section discussing our action 

on these submittals. 

2. 2012 EPA Action on 2011 and 2008 

Utah RH SIPs 

On December 14, 2012, EPA partially 

approved and partially disapproved the 

2011 Utah RH SIP.44 We approved all 

sections of the 2011 Utah RH SIP as 

meeting the requirements of 40 CFR 

51.309, with the exception of the 

requirements under 40 CFR 

51.309(d)(4)(vii) pertaining to NOX and 

PM10 BART. EPA’s partial disapproval 

action was based on the following: (1) 

Utah did not take into account the five 

statutory factors in its BART analyses 

for NOX and PM10; and (2) the 2011 

Utah RH SIP did not contain the 

provisions necessary to make the BART 

limits practically enforceable as 

required by section 110(a)(2) of the CAA 

and 40 CFR 51, appendix V.45

We also approved two sections of the 

2008 Utah RH SIP. Specifically, we 

approved UAR R307–250—Western 

Backstop Sulfur Dioxide Trading 

Program and R307–150—Emission 

Inventories. We took no action on the 

rest of the 2008 submittal as the 2011 

submittal superseded and replaced the 

remaining sections of the 2008 

submittal. We also took no action on the 

December 12, 2003 and August 8, 2004 

submittals as these were superseded by 

the 2011 submittal. 

On November 8, 2011, we separately 

proposed approval of Section G—LongTerm Strategy for Fire Programs of the 

May 26, 2011 submittal and finalized 

our approval of that action on January 

18, 2013.46

3. 2013 Litigation 

In 2013, conservation groups sued 

EPA in the U.S. Court of Appeals for the 

Tenth Circuit on our approval of the 

SO2 backstop trading program as an 

alternative to BART. On October 21, 

2014, the court upheld EPA’s finding 

that the trading program was better than 

BART.47

4. 2015 Utah RH SIPs 

On June 4, 2015, the Governor of the 

State of Utah submitted to EPA a 

revision to its Regional Haze SIP under 

40 CFR 51.309 of the RHR (‘‘June 2015 

Utah RH SIP’’), specifically to address 

the requirements under 40 CFR 

51.309(d)(4)(vii) pertaining to NOX and 

PM10 BART. Utah developed the June 

2015 Utah RH SIP in response to EPA’s 

December 14, 2012 partial disapproval 

of the 2011 Utah RH SIP. The June 2015 

Utah RH SIP evolved from a draft SIP 

on which Utah sought public comment 

in October 2014. After receiving 

extensive public comments, Utah 

decided to pursue a BART alternative 

(‘‘Utah BART Alternative,’’ ‘‘BART 

Alternative,’’ or ‘‘Alternative’’) under 40 

CFR 51.308(e)(2) that takes credit for 

early NOX reductions due to combustion 

controls installed at PacifiCorp’s Hunter 

and Huntington power plants in 

addition to NOX, SO2, and PM10

reductions from the August 2015 

retirement of PacifiCorp’s nearby 

Carbon power plant. The June 2015 

Utah RH SIP also includes measures to 

make the SIP requirements practically 

enforceable and includes additional 

information pertaining to the PM10

BART determinations for Hunter and 

Huntington to address deficiencies 

identified by EPA in our December 2012 

partial disapproval. 

On October 20, 2015, Utah submitted 

to EPA an additional revision to its 

Regional Haze SIP under 40 CFR 51.309 

of the RHR (‘‘October 2015 Utah RH 

SIP’’). This SIP includes an enforceable 

commitment to provide an additional 

SIP revision by mid-March 2018 to 

address concerns raised in public 

comments that the State would be 

double counting certain emissions 

reductions under the Utah BART 

Alternative in respect to milestone 

reporting for the SO2 backstop trading 

program. 

Sections 110(a)(2) and 110(l) of the 

CAA require that a state provide 

reasonable notice and public hearing 

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48See Utah Regional Haze State Implementation 

Plan, § XX.B.8, pp. 8–9 (Figures 1 and 2) (2011). 

49See id., at § XX.K.2, p. 116 (Table 24). 

50See U.S. Energy Information Administration, 

Electric Generating Capacity for 2011 (taken from 

Form EIA–860). See ‘‘EIA existing generating units 

2011.xls’’ spreadsheet in the docket. 

51 Id. 

before adopting a SIP revision and 

submitting it to us. Utah, after providing 

notice, accepted comments on the June 

2015 Utah RH SIP in April 2015 and 

accepted comments on the October 2015 

Utah RH SIP in mid-August through 

mid-September 2015. Following the 

comment period and legal review by the 

Utah Attorney General’s Office, the Utah 

Air Quality Board adopted the June 

2015 Utah RH SIP on June 3, 2015 and 

the October 2015 Utah RH SIP on 

October 7, 2015. The Governor 

submitted the SIP revisions to EPA on 

June 4, 2015 and October 20, 2015. 

IV. Utah’s Regional Haze SIP 

A. Summary of Elements Under EPA’s 

Previous Actions Upon Which We Are 

Relying 

Several SIP elements that we 

previously approved in our December 

2012 final rule and upon which we are 

relying in our current action include the 

following: 

1. Affected Class I Areas 

Utah provided two maps in Section 

XX of its 2011 RH SIP, one showing the 

locations of the 16 Class I areas on the 

Colorado Plateau and one showing the 

locations of the five in Utah (Arches 

National Park, Bryce Canyon National 

Park, Canyonlands National Park, 

Capitol Reef National Park, and Zion 

National Park).48 Utah also provided a 

comparison of the monitored 2000–2004 

baseline visibility conditions in 

deciviews for the 20 percent best and 20 

percent worst days to the projected 

visibility improvement for 2018 for the 

16 Class I areas.49

We determined that the State’s SIP 

satisfies the requirements of 40 CFR 

51.309(d)(2) for this element in our 

December 14, 2012 rulemaking. 

2. BART-Eligible Sources 

Pursuant to 40 CFR 51.308(e)(2)(i)(A), 

the 2011 Utah RH SIP listed the BARTeligible sources covered by the backstop 

trading program (see Table 1). The State 

identified the following BART-eligible 

sources in Utah: PacifiCorp Hunter 

Units 1 and 2 and PacifiCorp 

Huntington Units 1 and 2. 

PacifiCorp’s Hunter Power Plant 

(Hunter), is located in Castle Dale, Utah 

and consists of three electric utility 

steam generating units. Of the three 

units, only Units 1 and 2 are subject to 

BART. Hunter Units 1 and 2 have a 

nameplate generating capacity of 488.3 

MW each.50 The boilers are tangentially 

fired pulverized coal boilers, burning 

bituminous coal from the Deer Creek 

Mine in Utah. 

PacifiCorp’s Huntington Power Plant 

(Huntington), is located in Huntington 

City, Utah, and consists of two electric 

utility steam generating units. 

Huntington Units 1 and 2 have a 

nameplate generating capacity of 498 

MW each.51 The boilers are tangentially 

fired pulverized coal boilers, burning 

bituminous coal from the nearby Deer 

Creek Mine. 

We determined that the State’s SIP 

satisfies the requirements of 40 CFR 

51.309(e)(2)(i)(A) in our December 14, 

2012 rulemaking. 

3. Sources Subject-to-BART 

Pursuant to 40 CFR 51.308(e)(2)(i)(B), 

the 2011 Utah RH SIP described the 

State’s source modeling that determined 

which of the BART-eligible sources 

within Utah cause or contribute to 

visibility impairment and are thus 

subject-to-BART (more information on 

subject-to-BART sources and modeling 

can be found in Section XX.D.6 of the 

2011 Utah RH SIP and section V.F of 

our May 16, 2012 proposed rulemaking). 

Table 1 shows Utah’s BART-eligible 

sources covered by the 309 SO2

backstop program, Hunter Units 1 and 2, 

and Huntington Units 1 and 2, and 

indicates that all are subject-to-BART. 

We determined that the State’s SIP 

satisfies the requirements of 40 CFR 

51.308(e)(2)(i)(B) in our December 14, 

2012 rulemaking. 

TABLE 1—SUBJECT-TO-BART STATUS FOR UTAH’S SECTION 309 BART-ELIGIBLE SOURCES

Company Source Unit ID Service 

date BART Category 

Generating 

capacity 

(MW) 

Coal type Boiler type Subjectto-BART? 

PacifiCorp ....... Hunter ........... 1 1978 Fossil Fuel EGU ... 430 Bituminous ....... Tangential ........ Yes. 

PacifiCorp ....... Hunter ........... 2 1980 Fossil Fuel EGU ... 430 Bituminous ....... Tangential ........ Yes. 

PacifiCorp ....... Huntington ..... 1 1977 Fossil Fuel EGU ... 430 Bituminous ....... Tangential ........ Yes. 

PacifiCorp ....... Huntington ..... 2 1974 Fossil Fuel EGU ... 430 Bituminous ....... Tangential ........ Yes. 

We note that Section XX.D.6 in the 

June 2015 Utah RH SIP supersedes 

Section XX.D.6 in the 2011 Utah RH SIP 

and that some reformatting occurred. As 

Utah did not make substantive revisions 

to the SIP provisions addressing BARTeligible sources and subject-to-BART 

sources, XX.D.6.b and XX.D.6.c, in the 

2011 SIP, we are not proposing any 

additional action on these provisions in 

this preamble. 

B. Summary of Utah’s BART Alternative 

and PM10 BART SIP Revision 

Utah’s June 2015 RH SIPs include the 

following SIP provisions: 

• Revised R307–110–17, General 

Requirements: State Implementation 

Plan. Section IX, Control Measures for 

Area and Point Sources, Part H, 

Emissions Limits (incorporates by 

reference most recently amended SIP 

Section IX, Part H into state rules) 

• Revised R307–110–28, General 

Requirements: State Implementation 

Plan, Regional Haze (incorporates by 

reference most recently amended SIP 

Section XX into state rules) 

• Revised SIP Section XX.D.6 

Regional Haze. Long-Term Strategy for 

Stationary Sources. Best Available 

Retrofit Technology (BART) Assessment 

for NOX and PM (supersedes Section 

XX.D.6 in the 2011 Utah RH SIP) 

• New SIP Section IX.H.21 General 

Requirements: Control Measures for 

Area and Point Sources, Emission 

Limits and Operating Practices, 

Regional Haze Requirements 

• New SIP Section IX.H.22 Source 

Specific Emission Limitations: Regional 

Haze Requirements, Best Available 

Retrofit Technology. 

The June 2015 Utah RH SIP, including 

the five SIP revisions listed previously, 

consists of the following three 

components: (1) a NOX BART 

alternative that includes NOX and SO2, 

and PM10 emission reductions from 

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52Utah Regional Haze State Implementation Plan, 

p. 7 (TSD Chapter 1) (2011). 

53For PacifiCorp BART analyses reports, see TSD 

Chapter 2 of the SIP. 

Hunter Units 1–3, Huntington Units 1 

and 2, and Carbon Units 1 and 2 and 

PM10 emission reductions from Carbon 

Units 1 and 2; (2) BART determinations 

for PM10 at Hunter Units 1 and 2 and 

Huntington Units 1 and 2 based on a 

streamlined analysis; and (3) 

monitoring, recordkeeping and 

reporting requirements for the Utah 

BART Alternative and PM10 BART 

emission limits to make the SIP 

requirements practically enforceable. 

The emission limits in the June 2015 

Utah RH SIP are provided in Table 2. 

We further explain the three 

components of the SIP. 

TABLE 2—EMISSION LIMITS AND SHUTDOWN IN UTAH’S BART ALTERNATIVE AND PM10 SIP1

Source Unit PM10 Limit 2

(lb/MMBtu, three-run test average) 

NOX Limit 3

(lb/MMBtu, 30-Day Rolling Average) SO2 Limit 

Hunter .................... 1 0.015 ................................................ 0.26 .................................................. NA. 

........................ 2 0.015 ................................................ 0.26 .................................................. NA. 

3 NA .................................................... 0.34 .................................................. NA. 

Huntington .............. 1 0.015 ................................................ 0.26 .................................................. NA. 

2 0.015 ................................................ 0.26 .................................................. NA. 

Carbon ................... 1 Shutdown by August 15, 2015 ........ Shutdown by August 15, 2015 ........ Shutdown by August 15, 2015. 

............................ 2 Shutdown by August 15, 2015 ........ Shutdown by August15, 2015 ......... Shutdown by August 15, 2015. 

1Obtained from the June 2015 Utah RH SIP, Section IX.H.22. 

2Based on annual stack testing. 

3Based on continuous emission monitoring system (CEMS) measurement. 

1. Utah BART Alternative 

Utah has opted to establish an 

alternative measure for NOX under 40 

CFR 51.308(e)(2). The State compared 

the Utah BART Alternative against a 

BART Benchmark of selective catalytic 

reduction (SCR) on all four BART units 

at Hunter and Huntington (Units 1 and 

2 at both plants). Utah’s BART 

Alternative consists of the shutdown of 

Carbon Units 1 and 2 and the 

installation of upgraded NOX

combustion controls (new low-NOX

burners [LNB] and overfire air [OFA]) 

on Hunter Unit 3 (all non-BART units). 

The Utah BART Alternative also 

includes the NOX reductions from 

installation of upgraded combustion 

controls (new LNB and separated 

overfire air [SOFA]) at Hunter Units 1 

and 2 and Huntington Units 1 and 2 (all 

BART units). The BART Benchmark 

includes the four BART units with 

combustion controls and SCR, Carbon’s 

baseline emissions, and Hunter Unit 3’s 

emissions with original combustion 

controls. The Utah BART Alternative is 

generally described in SIP Section 

XX.D.6 with a detailed demonstration 

included in Chapter 1 of Utah’s 

Technical Support Document (TSD) to 

support the State’s assertion that the 

alternative achieves greater reasonable 

progress than BART. The State’s 

demonstration is also described in more 

detail in section IV.C. 

A summary of the State’s estimates of 

emissions for the Utah BART 

Alternative and the BART Benchmark is 

provided in Table 3. EPA developed a 

summary of the emissions reductions 

based on Utah’s emission estimates and 

this is presented in Table 4. 

Utah indicated that PacifiCorp 

announced plans to shut down the 

Carbon Power Plant in 2015 due to the 

high cost to control mercury to meet the 

requirements of EPA’s Mercury and Air 

Toxics Standards (MATS).52 The State 

noted that the MATS rule was finalized 

in 2011, and the Utah RH SIP contains 

the requirement for the Carbon Power 

Plant to shut down in August 2015. 

Therefore, the emission reductions 

occur after the 2002 base year for Utah’s 

RH SIP and thus, Utah asserts, the 

reductions may be considered as part of 

an alternative strategy under 40 CFR 

51.308(e)(2)(iv). 

2. PM10 BART Determinations 

Utah included a streamlined analysis 

for PM10 BART determinations in 

accordance with section D.9 of the 

BART Guidelines for the BART units at 

Hunter and Huntington in the SIP TSD 

in Chapter 1, Section III and referenced 

this analysis in SIP Section XX.D.6. In 

the TSD, Utah summarized the BART 

analysis submitted by PacifiCorp in an 

August 5, 2014 report.53

PacifiCorp’s analysis identified three 

available technologies: Upgraded ESP 

and flue gas conditioning (0.040 lb/

MMBtu); polishing fabric filter (0.015 

lb/MMBtu); and replacement fabric 

filter (0.015 lb/MMBtu). The 2008 Utah 

RH SIP and BART determination had 

required PacifiCorp to install a fabric 

filter baghouse with a PM10 emission 

limit of 0.015 lb/MMBtu at the Hunter 

and Huntington BART units. Utah staff 

reviewed PacifiCorp’s 2012 analysis and 

determined that the baghouse 

technology required in 2008 is still the 

most stringent technology available and 

that 0.015 lb/MMBtu represents the 

most stringent emission limit. Utah 

cited EPA’s BART Guidelines and 

regional haze actions in Colorado, 

Wyoming, North Dakota and Montana to 

support these assertions. 

Utah determined that the PM10 BART 

emission limit for Hunter Units 1 and 2 

and Huntington Units 1 and 2 was 0.015 

lb/MMBtu based on a three-run test 

average. Utah noted that because the 

most stringent technology is in place at 

these units and that the PM10 emission 

limits have been made enforceable in 

the SIP, no further analysis was 

required. 

3. Monitoring, Recordkeeping and 

Reporting 

To address EPA’s partial disapproval 

of the 2011 Utah RH SIP for lack of 

enforceable measures and monitoring, 

recordkeeping and reporting 

requirements for the Utah BART 

Alternative and the PM10 BART 

determinations, Utah added two new 

subsections to SIP Sections IX, General 

H.21 and 22. Under H.21, Utah has 

detailed general requirements for 

sources subject to its regional haze 

program. Under H.22, Utah has listed 

source-specific regional haze 

requirements for Hunter, Huntington 

and Carbon. 

Specifically, under H.21, Utah added 

a new definition for boiler operating 

day. Utah noted that state rules R307– 

107–1 and R307–107–2 (applicability, 

timing and reporting of breakdowns) 

apply to sources subject to regional haze 

requirements under H.22. Utah required 

that information used to determine 

compliance shall be recorded for all 

periods when the source is in operation, 

and that such records shall be kept for 

a minimum of five years. Under H.21, 

Utah specified that emission limitations 

listed in H.22 shall apply at all times 

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54Letter from Department of Environmental 

Quality, State of Utah to EPA, DAQP–120–15 (Dec. 

10, 2015). 

55Utah Regional Haze State Implementation Plan, 

Technical Support Document, Ch. 1 (Reference 

Table 2) (2015). 

and identified stack testing 

requirements to show compliance with 

those emission limitations. Finally, 

under H.21, Utah also specified the 

requirements for continuous emission 

monitoring by listing the requirements 

and cross-referencing the State’s rule for 

continuous emission monitoring system 

requirements, R307–170 as well as 40 

CFR part 13 and 40 CFR part 60, 

appendix B—Performance 

Specifications. Utah included the 

requirements to calculate hourly average 

NOX concentrations for any hour in 

which fuel is combusted and a new 30- 

day rolling average emission rate at the 

end of each boiler operating day. Utah 

also noted that the hourly average NOX

emission rate is valid only if the 

minimum number of data points 

specified in R307–170 is acquired for 

both the pollutant concentration 

monitor and diluent monitor. 

Under H.21, Utah did not provide for 

reporting of violations of PM10

emissions limitations for instances other 

than breakdowns (e.g., stack test 

violations). However, the State provided 

a commitment letter on December 10, 

2015 to address this deficiency with a 

SIP revision within one year of EPA’s 

final action on the June 4, 2015 RH 

SIP.54

Under H.22, Utah provided the NOX

and PM10 emission limitations for 

Hunter Units 1 through 3 and 

Huntington Units 1 and 2, a requirement 

to perform annual stack testing for PM10, 

and a requirement to measure NOX via 

continuous emission monitoring for the 

sources covered under the Utah BART 

Alternative. Under H.22, Utah also 

listed the enforceable conditions related 

to closing Carbon Units 1 and 2 by 

August 15, 2015 including PacifiCorp’s 

and Utah’s notification and permit 

rescission obligations. 

C. Summary of Utah’s Demonstration 

for Alternative Program 

As discussed previously in 

background section III.A, a state may 

opt to implement an alternative measure 

rather than to require sources subject to 

BART to install, operate, and maintain 

BART. Utah has included the following 

information in its June and October 

2015 RH SIPs to address the regulatory 

criteria for an alternative program: 

1. A List of All BART-Eligible Sources 

Within the State 

Pursuant to 40 CFR 51.308(e)(2)(i)(A) 

and (B), the SIP must include a list of 

all BART-eligible sources within the 

State. Utah included a list of BARTeligible sources and noted the following 

sources are all covered by the 

alternative program: 

• PacifiCorp Hunter, Unit 1 

• PacifiCorp Hunter, Unit 2 

• PacifiCorp, Huntington, Unit 1 

• PacifiCorp, Huntington, Unit 2 

Utah provided the same list of BARTeligible sources in the 2011 RH SIP. We 

determined that the State’s SIP satisfies 

the requirements of 40 CFR 

51.309(e)(2)(i)(A) in our December 14, 

2012 rulemaking. 

2. A List of All BART-Eligible Sources 

and All BART Source Categories 

Covered by the Alternative Program 

Pursuant to 40 CFR 51.308(e)(2)(i)(B), 

each BART-eligible source in the State 

must be subject to the requirements of 

the alternative program or have a 

federally enforceable emission 

limitation determined by the State and 

approved by EPA as meeting BART. In 

this instance, the alternative program 

covers all the BART-eligible sources in 

the state, Hunter Units 1 and 2 and 

Huntington Units 1 and 2, in addition 

to three non-BART units, PacifiCorp’s 

Hunter Unit 3 and Carbon Units 1 and 

2. 

Utah provided the same list of BART 

sources subject to an alternative 

program in the 2011 RH SIP. We 

determined that the State’s SIP satisfies 

the requirements of 40 CFR 

51.309(e)(2)(i)(B) in our December 14, 

2012 rulemaking. 

3. Analysis of BART and Associated 

Emission Reductions Achievable 

Pursuant to 40 CFR 51.308(e)(2)(i)(C), 

the SIP must include an analysis of 

BART and associated emission 

reductions at Hunter and Huntington. In 

the June 2015 Utah RH SIP, the State 

compared the Utah BART Alternative to 

a BART Benchmark that included the 

most stringent NOX BART controls, SCR 

plus new LNBs and SOFA, at the four 

BART units. 

4. Analysis of Projected Emissions 

Reductions Achievable Through the 

BART Alternative 

Pursuant to 40 CFR 51. 308(e)(2)(D), 

the SIP must include ‘‘[a]n analysis of 

the projected emissions reductions 

achievable through the . . . alternative 

measure.’’ A summary of the State’s 

estimates of emissions in tons per year 

(tpy) for the Utah BART Alternative and 

the BART Benchmark is provided in 

Table 3. A summary of the emissions 

reductions based on those emission 

estimates is presented in Table 4. 

TABLE 3—ESTIMATED EMISSIONS UNDER UTAH’S BART BENCHMARK AND THE BART ALTERNATIVE 55

Units 

NOX emissions (tpy) SO2 emissions (tpy) PM10 emissions (tpy) 4 Combined 

Benchmark 2 Alternative 3 Benchmark 2 Alternative 3 Benchmark Alternative Benchmark Alternative 

Carbon 1 .......... 1,408 0 3,388 0 221 0 5,016 0 

Carbon 2 .......... 1,940 0 4,617 0 352 0 6,909 0 

Hunter 1 1 ......... 775 3,412 1,529 1,529 169 169 2,473 5,100 

Hunter 2 ........... 843 3,412 1,529 1,529 169 169 2,541 5,110 

Hunter 3 ........... 6,530 4,622 1,033 1,033 122 122 7,685 5,777 

Huntington 1 ..... 809 3,593 1,168 1,168 176 176 2,153 4,937 

Huntington 2 ..... 856 3,844 1,187 1,187 200 200 2,243 5,231 

Total .......... 13,161 18,882 14,451 6,446 1,409 836 29,020 26,164 

1 Hunter 1 controls were installed in the spring of 2014, therefore Hunter 2 actual emissions are used as a surrogate. 

2 Most stringent NOX rate for BART-eligible units (see email and spreadsheet, ‘‘Attachment to Utah September 16, 2015 email, BART Analysis.pdf’’ in the docket, inadvertently omitted from Utah TSD), 2012–2013 actual emissions Carbon, 2001–2003 actual emissions Hunter 3 (EPA 

Acid Rain Program). 3Average actual emissions 2012–13 for Hunter and Huntington units, EPA Acid Rain Program. 

4Actual emissions for 2012, Utah Department of Air Quality annual inventory. 

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56Utah referenced that greater reasonable 

progress can be demonstrated using one of two 

methods: (1) greater emission reductions than under 

BART (40 CFR 51.308(e)(3)); or (2) based on the 

clear weight of evidence (40 CFR 51.308(e)(2)(i)(E)). 

Utah further explained that: As the U.S. Circuit 

Court of Appeals for the 10th Circuit recently 

observed, the state is free to choose one method or 

the other. WildEarth Guardians v. E.P.A., 770 F.3d 

919, 935–37 (10th Cir. 2014). Finally, Utah noted 

that the court characterized the former approach as 

‘‘quantitative’’ and the latter as ‘‘qualitative,’’ and 

specifically sanctioned the use of qualitative factors 

under the clear weight of evidence. 57Utah noted that EPA has proposed approval of 

an Alternative Measure for the Apache Generating 

Station in Arizona on similar ‘‘weight of evidence’’ 

grounds. 79 FR 56322, 56327 (Sept. 19, 2014). Utah 

also noted that EPA has approved a similar 

Alternative Measure in Washington, based in part 

on a reduction in the number of days of impairment 

greater than 0.5 dv and 1.0 dv. 79 FR 33438, 33440– 

33442 (June 11, 2014). 

58Utah Regional Haze State Implementation Plan, 

Technical Support Document, Ch. 1 (Reference 

Table 5) (2015). 

TABLE 4—EPA SUMMARY OF EMISSION REDUCTIONS ACHIEVABLE WITH THE UTAH BART ALTERNATIVE AS COMPARED

TO THE BART BENCHMARK

Description 

Combined emissions for all units 

(tpy) 

NOX SO2 PM10 Combined 

BART Benchmark ............................................................................................................ 13,161 14,451 1,409 29,020 

BART Alternative ............................................................................................................. 18,882 6,446 836 26,164 

Emission Reduction (BART Benchmark minus BART Alternative) 1 ............................... ¥5,721 8,005 573 2,856 

1A negative value indicates the BART Alternative results in more emissions of the specified pollutant in comparison to the BART Benchmark. 

5. A Determination That the Alternative 

Achieves Greater Reasonable Progress 

Than Would Be Achieved Through the 

Installation and Operation of BART 

Pursuant to 40 CFR 51.308(e)(2)(i)(E), 

the State must provide a determination 

under 40 CFR 51.308(e)(3) or otherwise 

based on the clear weight of evidence 

that the alternative achieves greater 

reasonable progress than BART. 40 CFR 

51.308(e)(3), in turn, provides two 

different tests for determining whether 

the alternative achieves greater 

reasonable progress than BART. 

Utah first used the ‘‘greater emission 

reductions’’ test in 40 CFR 51.308(e)(3) 

to support its assertion that the BART 

Alternative achieves greater reasonable 

progress. In the June 2015 Utah RH SIP, 

the State noted that the Hunter, 

Huntington and Carbon plants are all 

located within 40 miles of each other in 

Central Utah. Utah stated that because 

of the close proximity of the three 

plants, the distribution of emissions 

would not be substantially different 

under the Utah BART Alternative than 

under BART. With the alternative 

measure resulting in greater aggregate 

emission reductions by 2,856 tons/year 

(tpy) (described in Table 4), Utah 

asserted that the alternative measure 

may be deemed to achieve greater 

reasonable progress than BART under 

51.308(e)(3). 

Utah also chose to conduct a weightof-evidence analysis under 51.308(e)(2) 

based on emissions from the Hunter, 

Huntington, and Carbon power plants 

and considered the following 

evidence: 56

a. Annual Emissions Comparison for 

Visibility-impairing Pollutants 

The emissions of visibility-impairing 

pollutants from both the Utah BART 

Alternative and the BART Benchmark, 

as estimated by the State, are 

summarized in Table 3. Compared with 

the Utah BART Benchmark, the State 

projects that the Utah BART Alternative 

will result in 5,721 tpy more NOX

emissions, 8,005 tpy fewer SO2

emissions and 573 tpy fewer PM10

emissions. Utah also found that the 

combined emissions of NOX, SO2 and 

PM10 will be 2,856 tpy lower under the 

Utah BART Alternative. 

b. Improvement in the Number of Days 

With Significant Visibility Impairment 

Utah provided modeling results to 

assess the improvement in the number 

of days with significant visibility 

impairment—that is, the improvement 

in the number of days with impacts that 

either cause (> 1.0 dv) or contribute (> 

0.5 dv) to visibility impairment. The 

State presented this information in a 

number of ways, including: (1) the 

average number of days per year for 

three years modeled (2001–2003) with 

impacts above the cause and contribute 

thresholds for the nine affected Class I 

areas under the BART Alternative as 

compared to under the BART 

Benchmark; and (2) the total number of 

days for the three years modeled with 

impacts above the thresholds for the 

nine Class I areas under the two 

scenarios.57

On average for the three years 

modeled, the Utah BART Alternative 

causes visibility impairment (>1.0 dv) 

on fewer days than the BART 

Benchmark (258 days vs. 264 days, for 

the nine affected Class I areas). 

Similarly, on average for the three years 

modeled, the Utah BART Alternative 

also contributes to visibility impairment 

(>0.5 dv) on fewer days than the BART 

Benchmark (441 days vs. 499 days for 

the nine affected Class I areas). See 

Tables 5 and 6. 

TABLE 5—AVERAGE (2001–2003) NUMBER OF DAYS >1.0 dv IMPACT 58

Class I area Basecase BART 

alternative 

BART 

benchmark 

Arches .......................................................................................................................................... 128 68 77 

Black Canyon of the Gunnison .................................................................................................... 36 10 9 

Bryce Canyon .............................................................................................................................. 19 9 8 

Canyonlands ................................................................................................................................ 141 87 87 

Capitol Reef ................................................................................................................................. 68 42 41 

Flat Tops ...................................................................................................................................... 46 13 15 

Grand Canyon ............................................................................................................................. 22 11 10 

Mesa Verde ................................................................................................................................. 40 13 12 

Zion .............................................................................................................................................. 11 6 6 

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59See id., at Technical Support Document, Ch. 1 

(Reference Table 6). 

60See id., at Technical Support Document, 

Chapter 6.b (Summary of Visibility Modeling). 

TABLE 5—AVERAGE (2001–2003) NUMBER OF DAYS >1.0 dv IMPACT 58—Continued 

Class I area Basecase BART 

alternative 

BART 

benchmark 

Total ...................................................................................................................................... 511 258 264 

TABLE 6—AVERAGE (2001–2003) NUMBER OF DAYS >0.5 dv IMPACT 59

Class I area Basecase BART 

alternative 

BART 

benchmark 

Arches .......................................................................................................................................... 176 109 130 

Black Canyon of the Gunnison .................................................................................................... 75 27 34 

Bryce Canyon .............................................................................................................................. 36 17 19 

Canyonlands ................................................................................................................................ 178 131 140 

Capitol Reef ................................................................................................................................. 96 63 65 

Flat Tops ...................................................................................................................................... 93 34 44 

Grand Canyon ............................................................................................................................. 38 19 20 

Mesa Verde ................................................................................................................................. 71 32 37 

Zion .............................................................................................................................................. 21 10 10 

Total ...................................................................................................................................... 784 441 499 

As for the total number of days over 

the course of the three modeled years, 

the Utah BART Alternative causes 

visibility impairment (> 1.0 dv) on 

fewer days than the BART Benchmark 

(775 days vs. 793 days for the nine 

affected Class I areas). Similarly, in total 

for the three years modeled, the Utah 

BART Alternative also contributes to 

visibility impairment (> 0.5 dv) on 

fewer days than the BART Benchmark 

(1,323 days vs. 1,498 days for the nine 

affected Class I areas). See Tables 7 and 

8. 

TABLE 7—TOTAL (2001–2003) NUMBER OF DAYS >1.0 dv IMPACT 60

Class I area Basecase BART 

alternative 

BART 

benchmark 

Arches .......................................................................................................................................... 383 203 230 

Black Canyon of the Gunnison .................................................................................................... 108 31 28 

Bryce Canyon .............................................................................................................................. 57 26 25 

Canyonlands ................................................................................................................................ 422 260 260 

Capitol Reef ................................................................................................................................. 204 126 124 

Flat Tops ...................................................................................................................................... 138 38 44 

Grand Canyon ............................................................................................................................. 67 34 30 

Mesa Verde ................................................................................................................................. 121 40 35 

Zion .............................................................................................................................................. 32 17 17 

Total ...................................................................................................................................... 1,532 775 793 

TABLE 8—TOTAL (2001–2003) NUMBER OF DAYS >0.5 dv IMPACT 61

Class I area Basecase BART 

alternative 

BART 

benchmark 

Arches .......................................................................................................................................... 529 327 391 

Black Canyon of the Gunnison .................................................................................................... 224 81 103 

Bryce Canyon .............................................................................................................................. 107 50 57 

Canyonlands ................................................................................................................................ 533 393 420 

Capitol Reef ................................................................................................................................. 288 188 194 

Flat Tops ...................................................................................................................................... 280 101 133 

Grand Canyon ............................................................................................................................. 115 56 59 

Mesa Verde ................................................................................................................................. 213 97 110 

Zion .............................................................................................................................................. 63 30 31 

Total ...................................................................................................................................... 2,352 1,323 1,498 

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61See id. 

62Conforming permit amendments for the Carbon 

plant are due under the SIP by December 15, 2015. 

Section IX.H.22 of Utah’s SIP requires PacifiCorp to 

cease operation of Carbon by August 15, 2015, 

notify the State of the permanent closure by 

September 15, 2015, and request rescission of 

Operating Permit #700002004 and Approval Order 

DAQE–AN0100810005–08 by September 15, 2015. 

The State is then required to rescind the operating 

permit and approval order by December 15, 2015. 

63Copies of Administrative Orders DAQE– 

AN0102370012–08 and DAQE–AN0102380021–10 

are included in the docket. 

64Utah Regional Haze State Implementation Plan, 

Technical Support Document, Ch. 1, p. 12 (2015). 

65 Id. at p. 15. 

66 Id. at p. 12. 

67 Id. at p. 14. 

68 Id. at p.13. 

69 Id. 

70 Id. at pp. 16–19. 

71PacifiCorp quantified the energy penalty 

associated with SCR in its August 4, 2014 BART 

Analysis Update, Appendix A. See id. at p. 26 

(Table 13 presents this information). 

c. 98th Percentile Impact (dv) 

Utah explained that the only metric it 

evaluated that showed greater 

improvement for the BART Benchmark 

in comparison to the BART Alternative 

was the 98th percentile metric when 

visibility impacts were averaged across 

all Class I areas and meteorological 

years modeled. Utah’s comparison of 

the modeled visibility impacts on the 

98th percentile day (8th highest 

impacted day in a given meteorological 

year) for the most impacted year shows 

that the BART Benchmark would result 

in greater visibility improvement at five 

of the nine Class I areas, and is better 

on average across all nine Class I areas 

(0.11 dv difference). At two of the most 

impacted Class I areas, Canyonlands 

and Capitol Reef, Utah found that the 

98th percentile metric indicates the 

BART Benchmark has 0.76 dv and 0.57 

dv, respectively, greater improvement 

than the Utah BART Alternative. At 

other Class I areas, Utah found that the 

98th percentile metric indicates that the 

BART Alternative provides greater 

visibility improvement (for example, 

0.44 dv at Flat Tops). 

Utah noted that because high nitrate 

values occur primarily in the winter 

months, the BART Benchmark achieved 

greater modeled visibility improvement 

on certain winter days with high nitrate 

impacts. Utah stated its position that 

there is greater uncertainty regarding the 

effect of NOX reductions on wintertime 

nitrate values, and thus on visibility, 

because past NOX emission reductions 

have not resulted in corresponding 

reductions in monitored nitrate values 

during the winter months. Utah noted it 

has greater confidence in the visibility 

improvement due to reductions of SO2

because past reductions have resulted in 

corresponding reductions in monitored 

sulfate values throughout the year. 

d. Annual Average Impact (dv) 

As modeled by Utah, which used 

CALPUFF modeling results, the average 

annual dv impact is better under the 

Utah BART Alternative at five of the 

nine Class I areas, and is better on 

average across all the Class I areas. The 

average impact was calculated by 

averaging all daily modeling results for 

each year and then calculating a threeyear average from the annual average. 

Utah’s information shows that the BART 

Alternative is better than the BART 

Benchmark by 0.009 dv on average 

across all nine Class I areas. 

e. 90th Percentile Impact (dv) 

Utah’s comparison of the modeled 

visibility impacts at the 90th percentile 

(the 110th highest day across three 

years) dv impact shows that the Utah 

BART Alternative is better at seven of 

the nine Class I areas and is better 

averaged both across three years and 

across nine Class I areas by 0.006 dv. 

f. Timing for the Emissions Reductions 

Utah provided the schedule for 

installation of controls as noted in Table 

9. Utah discussed that NOX reductions 

at Hunter Units 1 and 2 and Huntington 

Units 1 and 2 occurred between 2006 

and 2014, earlier than was required by 

the Regional Haze Rule, providing a 

corresponding early and on-going 

visibility improvement. Utah cited the 

2014 10th Circuit Court of Appeals 

decision regarding the 309 program to 

support that such early reductions are 

properly included as weight of evidence 

in the State’s analysis. 

TABLE 9—INSTALLATION SCHEDULE

Source/Unit Timing of control installation 

or shutdown 

Hunter 1 ......... New LNB and SOFA–Spring 

2014. 

Hunter 2 ......... New LNB and SOFA–Spring 

2011. 

Hunter 3 ......... New LNB and OFA–Summer 

2008. 

Huntington 1 .. New LNB and SOFA–Fall 

2010. 

Huntington 2 .. New LNB and SOFA–December 2006. 

Carbon 1 ........ Shutdown August 2015. 

Carbon 2 ........ Shutdown August 2015. 

The reductions under the Utah BART 

Alternative are required under the State 

SIP by August 2015, as noted in Table 

5, providing an early and on-going 

visibility benefit as compared to 

BART.62 Installation and operation of 

the combustion control upgrades at 

Hunter and Huntington were made 

enforceable under Administrative 

Orders DAQE–AN0102370012–08 and 

DAQE–AN0102380021–10.63

g. IMPROVE Monitoring Data 

Utah’s SIP presents sulfate and nitrate 

monitoring data at the Canyonlands 

IMPROVE monitor that shows that 

‘‘sulfates are the dominant visibility 

impairing pollutant’’ 64 and that sulfate 

levels have decreased,65 and references 

similar results at other Class I areas in 

the TSD.66 Utah also presents data on 

trends in emissions from EGUs showing 

substantial reductions in emissions of 

both SO2 and NOX.67 Based on these 

data, Utah indicates it ‘‘has confidence 

that the SO2 reductions will achieve 

meaningful visibility improvement,’’ 

under the Utah BART Alternative, while 

‘‘the visibility improvement during the 

winter months due to NOX reductions is 

much more uncertain.’’ 68 Utah makes 

this point even though nitrate 

concentrations are highest in the winter, 

explaining that while there has been a 

reduction in NOX, the ammonium 

nitrate values do not show similar 

improvement in the winter months.69

Utah offers several possible 

explanations for the results, but does 

not provide any definitive 

conclusions.70

Utah also presents data on the 

seasonality of park visitation and 

monitoring data for nitrate and sulfates. 

The data show that the highest 

measured nitrate concentrations occur 

in winter during the period of lowest 

park visitation, and that sulfates affect 

visibility throughout the year and are 

the dominant visibility impairing 

pollutant from anthropogenic sources 

during the high visitation period of 

March through November. Utah 

concludes that it has greater confidence 

that reductions in SO2 will be reflected 

in improved visibility for visitors to the 

Class I areas, while reductions in NOX

will have a more uncertain benefit for 

visitors to Class I areas. 

h. Energy and Non-Air Quality Benefits 

Utah stated that energy and non-air 

quality environmental impacts are one 

of the factors listed in CAA section 

169A(g)(2) that must be considered 

when determining BART. The State 

noted that the Utah BART Alternative 

would avoid the energy penalty due to 

operating SCR units. PacifiCorp 

included the energy penalty in its BART 

analysis as part of the total cost for 

installing SCR on each of the units. The 

energy penalty costs are provided in 

Table 10. 

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72 40 CFR 51.308(e)(2)(iii). 

73See Memorandum from Lydia Wegman and 

Peter Tsirigotis, 2002 Base Year Emission Inventory 

SIP Planning: 8-hr Ozone, PM2.5, and Regional Haze 

Programs (Nov. 18, 2002), available at http://www3.

epa.gov/ttnchie1/eidocs/2002baseinven_

102502new.pdf. 

74 79 FR 33438, 33441–33442 (June 11, 2014); 79 

FR 56322, 56328 (Sept. 9, 2014). 

75See Utah Regional Haze State Implementation 

Plan, Technical Support Document, Ch. 1 

(Reference Table 15) (2015). 

TABLE 10—SCR ENERGY PENALTY 71

Source/unit 

Energy penalty 

kW $/year 

Hunter Unit 1 ............ 2,090 494,247 

Hunter Unit 2 ............ 2,090 494,247 

Huntington Unit 1 ...... 2,182 516,098 

Huntington Unit 2 ...... 2,182 516,098 

Total ................... 8,544 2,020,690 

Utah presented additional non-air 

quality benefits associated with the 

closure of the Carbon plant. First, it 

noted that solid wastes in the form of fly 

ash from the electrostatic precipitators 

and bottom ash conveyors which clean 

the residuals from the two steam 

generating units (the boilers), would be 

eliminated. These wastes are currently 

landfilled. The Carbon plant also runs 

water through the boilers as well as two 

cooling towers. This uses water and has 

associated wastewater discharge. 

Hauling the ash to the landfill requires 

additional fuel use and water or 

chemical dust suppression for 

minimization of fugitive dust. Finally, 

for maintenance and emergency 

purposes, Utah noted that the plant has 

a number of emergency generators, fire 

pumps, and ancillary equipment—all of 

which must be periodically operated, 

tested and maintained—with associated 

air emissions, fuel use, painting, and the 

like. Utah suggests that all of these nonair quality impacts are reduced as the 

result of closing the Carbon plant. 

i. Cost 

Utah cited PacifiCorp’s comments on 

the State’s proposed SIP revision that 

the BART Alternative not only produces 

greater reasonable progress, including 

lower emissions and improved 

visibility, but that it does so at a 

significant capital cost savings to 

PacifiCorp and its customers as 

compared to the BART Benchmark. 

Utah acknowledged that it did not 

officially determine the cost of installing 

SCR on the four BART units, but that it 

believed the cost of installing SCR 

would be significant. On the other hand, 

Utah noted that the Carbon Plant has 

already been closed due to the high cost 

of complying with the MATS rule. Utah 

explained that the costs to Utah rate 

payers (and those in other states served 

by PacifiCorp) to replace the power 

generated by the Carbon Plant have 

already occurred; there will be no 

additional cost to achieve the co-benefit 

of visibility improvement. As a result, 

Utah asserted that the BART Alternative 

not only achieves better visibility 

improvements than would be achieved 

by requiring SCR as BART at the four 

EGUs, but at a significantly lower cost. 

The State believed this presents a 

classic ‘‘win/win’’ scenario—the BART 

Alternative results in greater reasonable 

progress that is achieved at a much 

lower price compared to SCR. The State 

also noted that cost is one of the factors 

listed in CAA section 169A(g)(2) that 

should be considered when determining 

BART. 

6. Requirement That Emission 

Reductions Take Place During Period of 

First Long-Term Strategy 

Pursuant to 40 CFR 51.308(e)(2)(iii), 

the State must ensure that all necessary 

emission reductions take place during 

the period of the first long-term strategy 

for regional haze, i.e., by December 31, 

2018. The RHR further provides that, 

‘‘[t]o meet this requirement, the State 

must provide a detailed description of 

the . . . alternative measure, including 

schedules for implementation, the 

emission reductions required by the 

program, all necessary administrative 

and technical procedures for 

implementing the program, rules for 

accounting and monitoring emissions, 

and procedures for enforcement.’’ 72

As noted previously, the Utah SIP 

revision incorporates the revisions to 

R307–110–17, Section IX, Control 

Measures for Area and Point Sources, 

Part H, Emissions Limits, which 

includes provisions for implementing 

the Utah BART Alternative. In addition 

to the emission limitations for NOX and 

PM10, and the requirement for shutdown 

of the Carbon Plant listed in Table 2, the 

SIP includes compliance dates, 

operation and maintenance 

requirements, and monitoring, 

recordkeeping, and reporting 

requirements. 

7. Demonstration That Emissions 

Reductions From Alternative Program 

Will Be Surplus 

Pursuant to 40 CFR 51.308(e)(2)(iv), 

the SIP must demonstrate that the 

emissions reductions resulting from the 

alternative measure will be surplus to 

those reductions resulting from 

measures adopted to meet requirements 

of the CAA as of the baseline date of the 

SIP. The baseline date for regional haze 

SIPs is 2002.73 Utah developed the 2002 

baseline inventory in the 2008 RH SIP 

for regional modeling, evaluating the 

impact on Class I areas outside of the 

Colorado Plateau, and BART as outlined 

in EPA Guidance and the July 6, 2005 

BART Rule. Utah noted that 2002 is the 

baseline inventory that was used by 

other states throughout the country 

when evaluating BART under the 

provisions of 40 CFR 51.308 and that 

any measure adopted after 2002 is 

considered ‘‘surplus’’ under 40 CFR 

51.308(e)(2)(iv). Utah referenced other 

EPA actions that are consistent with this 

interpretation.74 Utah stated that the 

BART Benchmark scenario includes 

measures required before the baseline 

date of the SIP but does not include 

later measures that are credited as part 

of the BART Alternative scenario. 

To address potential concerns with 

double counting SO2 emissions 

reductions from the Carbon plant 

closure under both the 308 and 309 

programs, in addition to providing the 

explanation in the June 2015 SIP 

(discussed in TSD Chapter 1, Section X), 

Utah’s October 7, 2015 SIP also includes 

enforceable commitments to address 

these concerns. The State explained 

how the WRAP modeling done to 

support the Utah RH backstop trading 

program SIP included regional SO2

emissions based on the 2018 SO2

milestone and also included NOX and 

PM10 emissions from the Carbon plant. 

Actual emissions in the three-state 

region are calculated each year and 

compared to the milestones. Utah 

provided Table 11 to show that in 2011 

emissions were below the 2018 

milestone (141,849 tpy). Utah noted that 

the most recent milestone report for 

2013 demonstrates that SO2 emissions 

are currently 26 percent lower than the 

2018 milestone. Utah stated that the 

Carbon plant was fully operational in 

the years 2011–2013 when the 

emissions were below the 2018 

milestone. The State noted that the SO2

emission reductions from the closure of 

the Carbon plant are surplus to what is 

needed to meet the 2018 milestone 

established in Utah’s RH SIP. 

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76There is a typographical error in Chapter 1, 

section X.C, PacifiCorp Hunter Unit 3, p. 31. The 

reference to Hunter Unit 2 should be Unit 3 based 

on the section heading as well as confirmed 

emission limits in Utah Approval Order DAQE– 

AN0102370012–08. 

TABLE 11—SO2 MILESTONE TRENDS 75

Year Milestone 

(tpy) 

Three-Year 

average SO2

emissions 1

(tpy) 

Carbon plant 

SO2 emissions 

(tpy) 

2003 ............................................................................................................................................. 303,264 214,780 5,488 

2004 ............................................................................................................................................. 303,264 223,584 5,642 

2005 ............................................................................................................................................. 303,264 220,987 5,410 

2006 ............................................................................................................................................. 303,264 218,499 6,779 

2007 ............................................................................................................................................. 303,264 203,569 6,511 

2008 ............................................................................................................................................. 269,083 186,837 5,057 

2009 ............................................................................................................................................. 234,903 165,633 5,494 

2010 ............................................................................................................................................. 200,722 146,808 7,462 

2011 ............................................................................................................................................. 200,722 130,935 7,740 

2012 ............................................................................................................................................. 200,722 115,115 8,307 

2013 ............................................................................................................................................. 185,795 105,084 7,702 

2014 ............................................................................................................................................. 170,868 

2015 ............................................................................................................................................. 155,940 

2016 ............................................................................................................................................. 155,940 

2017 ............................................................................................................................................. 155,940 

2018 ............................................................................................................................................. 141,849 

1The three-year average is based on the emissions averaged for the current and two preceding years. 

For Hunter Unit 3, Utah also 

explained that PacifiCorp upgraded the 

LNB controls in 2008 and that the 

upgrade was not required under the 

requirements of the CAA as of the 2002 

baseline date of the SIP; the emission 

reductions from the upgrade are 

therefore considered surplus and 

creditable for the BART Alternative 

under 40 CFR 51.308(e)(2)(iv). Utah 

noted that prior to the 2008 upgrade, the 

emission rate for Hunter Unit 2 was 0.46 

lb/MMBtu heat input for a 30-day 

rolling average as required by Phase II 

of the Acid Rain Program.76

D. Summary of Utah’s Enforceable 

Commitment SIP Revision 

To address potential concerns that 

Utah would be double counting SO2

emissions reductions for the Carbon 

plant closure under both the 40 CFR 

51.308 and 309 programs, on October 7, 

2015 the State adopted an enforceable 

commitment into the Utah RH SIP at 

Chapter XX, Section N. Utah submitted 

this SIP revision to EPA on October 20, 

2015. In this commitment, the State 

explained that it will continue to report 

the historical emissions for the Carbon 

plant in the annual milestones reports 

from 2016 through the life of the 

backstop trading program. In addition, 

the State has committed to making 

revisions as necessary to SIP Section 

XX.D.3.c (‘‘Triggering the Trading 

Program’’) and State rule R307–150 

(‘‘Emission Inventories Program’’) as 

well as any other applicable provisions 

to implement the requirement for 

reporting Carbon’s historical emissions 

under the 309 program. The State notes 

it will follow its SIP adoption process 

when making these SIP revisions. The 

SIP will be adopted by the Governorappointed Air Quality Board through a 

rulemaking process that includes public 

participation. Once approved into the 

SIP, the commitment will be enforceable 

by both EPA and citizens under the 

CAA. 

The State noted that EPA has 

historically recognized that, under 

certain circumstances, issuing full 

approval may be appropriate for a SIP 

submission that consists of, in part, an 

enforceable commitment. Utah 

explained that its October 2015 

submission satisfies EPA’s requirements 

for enforceable commitments because it 

has adopted such a commitment for 

what is a small portion of its regional 

haze program in relation to its regional 

haze obligations as a whole. In addition, 

Carbon’s 8,005 tpy SO2 emissions 

reductions is small in comparison to the 

2018 milestone of 141,849 tpy described 

in Table 7. 

On the matter of timing, the State has 

committed to providing the required 

subsequent SIP submittal by mid-March 

2018. 

E. Consultation With FLMs 

Utah’s SIPs do not specifically discuss 

how it addressed the requirements of 40 

CFR 308(i)(2) for providing the FLMs 

with an opportunity for consultation at 

least 60 days prior to holding the public 

hearing for the June 2015 RH SIP. 

However, we are aware that Utah 

consulted with the FLMs and explain 

those efforts here. The State held an 

initial public comment period for 

proposed SIP amendments from 

November 1 through December 22, 

2014. The State provided the 

opportunity for the FLMs to review the 

preliminary draft SIP documents via 

email approximately 68 days prior to 

the public hearing that was held on a 

December 1, 2014. Copies of the email 

correspondence documenting this effort 

are included in the docket. 

Utah received a number of comments 

during the public comment period in 

late 2014. After reviewing the comments 

and consulting with EPA, Utah 

determined additional work was needed 

to develop a BART alternative measure 

that would take credit for emission 

reductions from the Carbon plant 

shutdown among other things. Utah 

held an additional public comment 

period from April 1 through April 30, 

2015. One of the FLMs, the National 

Park Service, provided extensive public 

comments to Utah during this second 

public comment period and Utah 

included responses to these comments, 

along with responses to other 

commenters, in the June 2015 RH SIP 

submittal along with other 

administrative documentation. 

The October 2015 Utah RH SIP was 

provided for public comment August 15 

through September 14, 2015, and we are 

not aware of any prior FLM consultation 

on this SIP. The FLMs did not submit 

comments during this public comment 

period. 

V. EPA’s Evaluation and Proposed 

Approval of Utah’s Regional Haze SIP 

As explained in section II.A, EPA is 

soliciting comments on two alternative 

proposals: A proposal to approve the 

State SIP in its entirety, and a proposal 

to partially approve and partially 

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77 40 CFR 51.308(e)(2)(i). 

78 40 CFR 51.308(e)(2)(iii). 

79 40 CFR 51.308(e)(2)(iv). 

80As presented in this proposal, while the 

majority of the State’s demonstration is contained 

in Chapter 1, EPA has identified additional 

information regarding the demonstration and we 

include references to the additional information. 

81 77 FR 74357 (Dec. 14, 2012). 

82 77 FR 74355, 74357 (Dec. 14, 2012). 83 40 CFR 51, appendix Y, section IV.D.1.9. 

disapprove the State SIP and to issue a 

FIP. The co-proposals detailed in this 

section and Section VI represent 

different conclusions regarding Utah’s 

NOX BART Alternative and the metrics 

the State has proposed to support this 

alternative. As described in this section, 

EPA is proposing to approve the two 

Utah 2015 RH SIP revisions. 

Alternatively, as discussed in section 

VI, EPA is co-proposing to disapprove 

the Utah’s June 2015 and October 2015 

RH SIP revisions and promulgate a FIP. 

This document is written as two 

separate proposals in order to clearly 

present the options and solicit comment 

on each. EPA intends to finalize only 

one of these co-proposals; however, we 

also acknowledge that additional 

information and comments may also 

lead the Agency to adopt final SIP 

and/or FIP regulations that differ 

somewhat from the co-proposals 

presented here regarding the BART 

Alternative, BART control technology 

option or emission limits, or impact 

other proposed regulatory provisions. 

A. Basis for Proposed Approval 

For the reasons described later on, 

EPA proposes to approve the two Utah 

2015 RH SIP revisions. Our proposed 

action is based on an evaluation of 

Utah’s regional haze SIP submittals 

against the regional haze requirements 

at 40 CFR 51.300–51.309 and CAA 

sections 169A and 169B. All general SIP 

requirements contained in CAA section 

110, other provisions of the CAA, and 

our regulations applicable to this action 

were also evaluated. The purpose of this 

proposed action is to ensure compliance 

with these requirements and to provide 

additional rationale to support our 

conclusions. 

B. Utah BART Alternative 

1. Summary of Utah BART Alternative 

Utah has opted to establish an 

alternative measure (or program) for 

NOX in accordance with 40 CFR 

51.308(e)(2). A description of the Utah 

BART Alternative is provided in section 

IV.B.1. The RHR requires that a SIP 

revision establishing a BART alternative 

include three elements as listed later. 

We have evaluated the Utah BART 

Alternative with respect to each of these 

elements. 

• A demonstration that the emissions 

trading program or other alternative 

measure will achieve greater reasonable 

progress than would have resulted from 

the installation and operation of BART 

at all sources subject to BART in the 

State and covered by the alternative 

program.77

• A requirement that all necessary 

emissions reductions take place during 

the period of the first long-term strategy 

for regional haze.78

• A demonstration that the emissions 

reductions resulting from the alternative 

measure will be surplus to those 

reductions resulting from measures 

adopted to meet requirements of the 

CAA as of the baseline date of the SIP.79

2. Demonstration of Greater Reasonable 

Progress for the Alternative Program 

As discussed previously in section 

III.E.1, pursuant to 40 CFR 

51.308(e)(2)(i), Utah must demonstrate 

that the alternative measure will achieve 

greater reasonable progress than would 

have resulted from the installation and 

operation of BART at all sources subject 

to BART in the State and covered by the 

alternative program. This 

demonstration, primarily included in 

Chapter 1 of the TSD of the Utah RH 

SIP,80 must be based on five criteria 

which are addressed later. 

a. A List of All BART-Eligible Sources 

Within the State 

As discussed previously in section 

IV.A.2, Utah included a list of BARTeligible sources and noted the following 

sources are all covered by the 

alternative program: 

• PacifiCorp Hunter, Unit 1 

• PacifiCorp Hunter, Unit 2 

• PacifiCorp, Huntington, Unit 1 

• PacifiCorp, Huntington, Unit 2 

EPA previously approved Utah’s 

BART eligibility determinations in our 

2012 rulemaking.81

b. A List of All BART-Eligible Sources 

and All BART Source Categories 

Covered by the Alternative Program 

As discussed previously in section 

IV.A.3, the Utah BART Alternative 

covers all the BART-eligible sources in 

the state, Hunter Units 1 and 2 and 

Huntington Units 1 and 2, in addition 

to three non-BART units, PacifiCorp’s 

Hunter Unit 3 and Carbon Units 1 and 

2. EPA previously approved Utah’s 

BART eligibility determinations in our 

2012 rulemaking.82

c. Analysis of BART and Associated 

Emission Reductions 

As noted in section IV.C.3, in the June 

2015 Utah RH SIP, the State compared 

the Utah BART Alternative to a BART 

Benchmark that included the most 

stringent NOX BART controls, SCR plus 

new LNBs and SOFA, at the four BART 

units. This is consistent with the 

streamlined approach described in Step 

1 of the BART Guidelines. The BART 

Guidelines note that a comprehensive 

BART analysis can be avoided if a 

source commits to a BART 

determination that consists of the most 

stringent controls available.83

We propose to find that Utah has met 

the requirement for an analysis of BART 

and associated emission reductions 

achievable at Hunter and Huntington 

under 40 CFR 51.308(e)(2)(i)(C). 

d. Analysis of Projected Emissions 

Reductions Achievable Through the 

BART Alternative 

As discussed previously in section 

IV.C.4, a summary of Utah’s estimates of 

emissions for the Utah BART 

Alternative and the BART Benchmark is 

provided in Table 3. We propose to find 

that Utah has met the requirement for an 

analysis of the projected emissions 

reductions achievable through the 

alternative measure under 40 CFR 

51.308(e)(2)(i)(D). 

e. A Determination That the Alternative 

Achieves Greater Reasonable Progress 

Than Would Be Achieved Through the 

Installation and Operation of BART 

Greater Reasonable Progress Based on 

40 CFR 51.308(e)(3)’s Greater Emission 

Reductions Test 

EPA’s evaluation of the State’s 

demonstration based on 40 CFR 

51.308(e)(3) is located in section 

VI.B.2.e. 

Greater Reasonable Progress Based on 

40 CFR 51.308(e)(2)’s Weight-ofEvidence Test 

Although Utah found that the BART 

Alternative demonstrates greater 

reasonable progress under 40 CFR 

51.308(e)(3), it also chose to conduct a 

weight-of-evidence analysis under 40 

CFR 51.308(e)(2) based on a BART 

Alternative involving the Hunter, 

Huntington, and Carbon power plants 

and considered the following evidence: 

i. Annual Emissions Comparison for 

Visibility-Impairing Pollutants 

The emissions of visibility-impairing 

pollutants from both the Utah BART 

Alternative and the BART Benchmark, 

as estimated by Utah, are summarized in 

Table 3 in section IV.C.4. Compared 

with the Utah BART Benchmark, the 

State projects that the Utah BART 

Alternative will result in 5,721 tpy more 

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84 40 CFR 51, appendix Y, section IV.D.5. 

85 70 FR 39130 (July 6, 2005). 

86 76 FR 58584 (Sept. 21, 2011). 

87 77 FR 24006 (Apr. 20, 2012). 

88 79 FR 33438, 33440–33441 (June 11, 2014). 

89 40 CFR 51, appendix Y, section IV.D.5. 

90See, e.g., 78 FR 79344 (Dec. 30, 2012)(proposed 

rule, FIP for Tesoro Refining and Intalco Refinery 

BART Alternatives); 79 FR 33438 (June 11, 

2014)(final rule, FIP for Tesoro Refining and Intalco 

Refinery BART Alternatives); 79 FR 56322, 56328 

(Sept. 19, 2014)(proposed approval of Arizona 

Apache BART Alternative); 80 FR 19220 (April 10, 

2015)(final approval of Arizona Apache BART 

Alternative); 77 FR 11827, 11837 (Feb. 28, 

2012)(proposed approval of Maryland BART 

Alternative); 77 FR 39938, 39940–1 (July 6, 

2012)(final approval of Maryland BART 

Alternative). 

91 70 FR at 39129. 

92See EPA Calculation of 98th Percentile 

Improvement for Utah Bart Alternative spreadsheet 

(in docket). 

93 Id. 

94 Id. 

NOX emissions, 8,005 tpy fewer SO2

emissions, and 573 tpy fewer PM10

emissions than the BART Benchmark. 

Utah also found that the combined 

emissions of NOX, SO2 and PM10 will be 

2,856 tpy lower under the BART 

Alternative. 

We propose to concur with Utah’s 

finding that the BART Alternative will 

achieve greater SO2 and PM10 emissions 

reductions and greater aggregate 

emissions reductions of all pollutants. 

We further propose to recognize that not 

all pollutants impact visibility equally 

and that the total emissions reductions 

of all pollutants is not necessarily a 

direct indicator of whether the BART 

Alternative or the BART Benchmark 

will achieve greater reasonable progress. 

However, for reasons described later in 

subsection vii for our evaluation of 

Utah’s IMPROVE monitoring metric, we 

propose to concur with Utah’s finding 

that SO2 emissions reductions should 

provide visibility benefits in all seasons 

and that sulfate is the largest contributor 

to visibility impairment at the affected 

Class I areas. Furthermore, we propose 

to find that these observations suggest 

that the BART Alternative is likely to 

achieve greater reasonable progress. We 

note that Utah has also provided 

CALPUFF modeling results for the 

BART Benchmark and BART 

Alternative scenarios to assess the 

relative visibility benefits of each. These 

modeling results are considered here by 

EPA as part of the overall weight-ofevidence analysis. 

ii. Improvement in the Number of Days 

With Significant Visibility Impairment 

As discussed previously in section 

IV.C.5, Utah provided modeling results 

to assess the improvement in the 

number of days with significant 

visibility impairment—that is, the 

improvement in the number of days 

with impacts that either cause (>1.0 dv) 

or contribute (>0.5 dv) to visibility 

impairment. 

The BART Guidelines provide that, 

when making a BART determination, a 

State may consider the number of days 

or hours that a threshold was 

exceeded.84 In developing the BART 

Guidelines, our example modeling 

analysis of a hypothetical source 

examined the number of days that 1.0 

dv and 0.5 dv thresholds were 

exceeded.85 In addition, we have used 

these metrics, and in particular the total 

number of days for the meteorological 

years modeled, in previous regional 

haze rulemakings such as for North 

Dakota,86 Montana,87 and 

Washington.88

This metric is useful in assessing the 

frequency and duration of significant 

visibility impacts from a source or small 

group of sources. Therefore, for this 

reason and because these metrics are 

supported by our regulations and past 

practice, we propose to find the State’s 

use of these metrics is appropriate. 

Moreover, we propose to find the 

difference in the total number of days 

impacted—18 fewer days greater than 

the causation threshold of 1.0 dv (775 

days for the BART Alternative vs. 793 

days for the BART Benchmark), and 175 

fewer days greater than the contribution 

0.5 dv threshold (1,323 days for the 

BART Alternative vs. 1,498 days for the 

BART Benchmark)—is an indication 

that the BART Alternative achieves 

greater reasonable progress. 

iii. 98th Percentile Impact (dv) 

As discussed previously in section 

IV.C.5, Utah explained that the only 

metric it evaluated that showed greater 

improvement for the BART Benchmark 

in comparison to the BART Alternative 

was the 98th percentile metric (when 

averaged across all Class I areas and 

meteorological years modeled). Utah’s 

comparison of the modeled visibility 

impacts on the 98th percentile day (8th 

highest impacted day in a given 

meteorological year) for the most 

impacted year shows that the BART 

Benchmark would result in greater 

visibility improvement at five of the 

nine Class I areas, and is slightly better 

on average across all nine Class I areas 

(0.11 dv difference). At the most 

impacted Class I areas, Canyonlands 

and Capitol Reef, Utah found that the 

98th percentile metric indicates the 

BART Benchmark has 0.76 dv and 0.57 

dv, respectively, more improvement 

than the BART Alternative. At other 

Class I areas, Utah found that the 98th 

percentile metric indicates that the 

BART Alternative provides greater 

visibility improvement (for example, 

0.44 dv at Flat Tops). 

The 98th percentile visibility impact 

is a key metric recommended by the 

BART Guidelines 89 when selecting 

BART controls. In addition, this is one 

of the primary metrics that EPA has 

relied on in evaluating prior regional 

haze actions that have included BART 

alternatives.90 In the BART Guidelines, 

EPA described this metric as an 

appropriate measure in determining the 

degree of visibility improvement 

expected from controls.91 Therefore, we 

propose to find that it is an appropriate 

metric for assessing the relative benefits 

of the Utah BART Alternative here. 

We note that when calculating 

visibility improvements for individual 

Class I areas, Utah mixed the impacts 

from different meteorological years 

between modeling scenarios (baseline, 

BART benchmark, and BART 

Alternative). This may introduce some 

error as the visibility improvements 

could be driven by year-to-year 

variability in meteorological conditions, 

as opposed to the differences in 

emission reductions between the BART 

Alternative and BART Benchmark. For 

this reason, in addition to considering 

the State’s numbers, EPA also calculated 

the visibility improvements for each 

modeling scenario using consistent 

meteorological years.92 Using this 

method, whether the BART Alternative 

resulted in lower 98th percentile 

impacts depended on both the 

particular Class I area and 

meteorological year modeled. In some 

years and some Class I areas, 

particularly some of the most impacted 

Class I areas, the BART Benchmark 

shows better visibility improvement 

than the BART Alternative. Notably, the 

BART Benchmark shows 0.93 dv greater 

improvement for Canyonlands in 2002 

and 0.75 dv greater improvement for 

Capitol Reef in 2001.93 By contrast, the 

BART Alternative shows 0.90 dv greater 

improvement for Arches in 2003 and 

0.43 dv greater improvement for Flat 

Tops in 2002.94 On the whole, when 

using this method, the BART 

Benchmark is better on average across 

all years and nine Class I areas (0.14 dv 

difference). See Table 12. We propose to 

find, consistent with the State’s 

evaluation, that this metric favors the 

BART Benchmark. 

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95 Id. 

96EPA final actions on BART alternatives that 

evaluated CALPUFF modeling analysis, which did 

not include consideration of annual average dv 

impacts include: 80 FR 19220 (April 10, 

2015)(Region 9, Apache); 79 FR 33438 (June 11, 

2014)(Region 10, Tesoro Refining and Alcoa Intalco 

Operations); 77 FR 39938 (July 6, 2012)(Region 3, 

Maryland HAA). 

97 70 FR 39121 (July 5, 2005). 

98Utah Regional Haze State Implementation Plan, 

Technical Support Document, Ch. 1, p. 12 (2015). 

99 Id. at p. 15. 

100 Id. at p.12. 

101 Id. at p. 14. 

102 Id. at p. 13. 

103 Id. 

104 Id. at pp. 16–19. 

105Fountoukis, C. & Nenes, A. ISORROPIA II: A 

Computationally Efficient Aerosol Thermodynamic 

Equilibrium Model for K∂, Ca2

∂, Mg2∂, NH4∂, 

Na∂, SO4

2¥, NO3

¥, Cl¥, H2O Aerosols, 7 Atmos. 

Chem. Phys., 4639–4659 (2007). 

TABLE 12—SUMMARY OF EPA COMPARISON OF UTAH CALPUFF 98TH

PERCENTILE MODELING RESULTS

BASED ON CONSISTENT METEOROLOGICAL YEARS 95

Class I Area 

Average 

visibility 

improvement 

of BART 

benchmark 

over BART 

alternative 

(delta dv)1

Arches ............................. ¥0.21 

Black Canyon of the 

Gunnison ..................... 0.06 

Bryce Canyon ................. 0.04 

Canyonlands ................... 0.78 

Capitol Reef .................... 0.59 

Flat Tops ......................... ¥0.15 

Grand Canyon ................ 0.06 

Mesa Verde .................... 0.12 

Zion ................................. 0.02 

Class I Area Average ..... 0.14 

1A negative value indicates the modeling 

results favor the BART Alternative. Results are 

based on the three-year average of results for 

2001, 2002 and 2003. 

iv. Annual Average Impact (dv) 

As discussed previously in section 

IV.C.5, Utah’s modeling shows that the 

average annual dv impact at all Class I 

areas is better under the Utah BART 

Alternative at five of the nine Class I 

areas, and is better on average across all 

the Class I areas. The average impact 

was calculated by averaging all daily 

modeling results for each year and then 

calculating a 3-year average from the 

annual average. Utah’s information 

shows that the BART Alternative is 

better than the BART Benchmark by 

0.009 dv on average across all nine Class 

I areas. While EPA has not considered 

this metric in the past,96 since the State 

includes it, we consider it here. 

Furthermore, the BART Guidelines state 

that, ‘‘in determining what, if any, 

emission controls should be required, 

the State will have the opportunity to 

consider the frequency, duration, and 

intensity of a source’s predicted effect 

on visibility.’’ 97 The annual average 

does provide an indication of the 

modeled visibility impacts for the entire 

year while the 98th percentile modeled 

results speak to a particular day (the 8th 

highest impacted day). Accordingly, and 

while we have typically relied primarily 

on the 98th percentile impacts in 

evaluating BART controls in other 

actions, we propose to find that the 

annual average impact provides 

additional useful information in 

considering Utah’s weight of evidence. 

However, given that the difference in 

this metric is small (0.009 dv), we 

propose to find that it only marginally 

supports a conclusion that the BART 

Alternative achieves greater reasonable 

progress. 

v. 90th Percentile Impact (dv) 

As discussed previously in section 

IV.C.5, Utah’s comparison of the 

modeled visibility impacts at the 90th 

percentile (the 110th highest day across 

three years) dv impact shows that the 

Utah BART Alternative is better at seven 

of the nine Class I areas and is slightly 

better averaged both across three years 

and across nine Class I areas (0.006 dv 

difference). We note that the use of the 

90th percentile impacts to evaluate 

alternatives has not been EPA’s practice 

for source-specific BART 

determinations; however, as discussed 

previously for the average dv impact 

metric, the BART Guidelines allow 

states to consider other visibility metrics 

in addition to the 98th percentile. Yet, 

because of the small difference between 

the two scenarios (0.006 dv), we 

propose to find that it only marginally 

supports a conclusion that the BART 

Alternative achieves greater reasonable 

progress. 

vi. Timing for the Emissions Reductions 

As discussed previously in section 

IV.C.5, Utah noted that reductions 

under the Utah BART Alternative will 

occur earlier than the BART Benchmark. 

The reductions under the Utah BART 

Alternative are required under the State 

SIP by August 2015, as noted in Table 

5, providing an early and on-going 

visibility benefit as compared to BART. 

Also notable is that combustion control 

upgrades at the Hunter and Huntington 

facilities have been achieving significant 

NOX reductions since the time of their 

installation between 2006 and 2014, 

depending on the unit. If, as proposed 

in section VI.C, BART for the four units 

is LNB/SOFA plus SCR, BART likely 

would be fully implemented sometime 

between 2019 and 2021. 

Therefore, we note that the reductions 

from the BART Alternative will occur 

before the BART Benchmark. 

vii. IMPROVE Monitoring Data 

Utah’s SIP presents sulfate and nitrate 

monitoring data at the Canyonlands 

IMPROVE monitor that show that 

‘‘sulfates are the dominant visibility 

impairing pollutant’’ 98 and that sulfate 

levels have decreased,99 and references 

similar results at other Class I areas in 

the TSD.100 Utah also presents data on 

trends in emissions from EGUs showing 

substantial reductions in emissions of 

both SO2 and NOX.101 Based on these 

data, Utah indicates it ‘‘has confidence 

that the SO2 reductions will achieve 

meaningful visibility improvement,’’ 

under the Utah BART Alternative, while 

‘‘the visibility improvement during the 

winter months due to NOX reductions is 

much more uncertain.’’ 102 Utah makes 

this point even though nitrate 

concentrations are highest in the winter, 

explaining that while there has been a 

reduction in NOX, the ammonium 

nitrate values do not show similar 

improvement in the winter months.103

Utah offers several possible 

explanations for the results, but does 

not provide any definitive 

conclusions.104

Utah also presents data on the 

seasonality of park visitation and 

monitoring data for nitrate and sulfates. 

The data show that the highest 

measured nitrate concentrations occur 

in winter during the period of lowest 

park visitation, and that sulfates affect 

visibility throughout the year and are 

the dominant visibility impairing 

pollutant from anthropogenic sources 

during the high visitation period of 

March through November. Utah 

concludes that it has greater confidence 

that reductions in SO2 will be reflected 

in improved visibility for visitors to the 

Class I areas, while reductions in NOX

will have a more uncertain benefit for 

visitors to Class I areas. 

We invite comment on the 

information and conclusions provided 

by Utah as summarized previously. 

We propose to concur with one of the 

State’s findings. We propose to find that 

visibility benefits associated with NOX

reductions are much more likely to 

occur in the winter months because this 

is when aerosol thermodynamics favors 

nitrate formation.105 By contrast, SO2

emissions reductions should provide 

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106Seinfeld, John H., Urban Air Pollution: State 

of the Science, 243 Science Magazine, No. 4892, 

745, 745–752 (1989). 

107While natural sources of haze from wildfires 

or windblown dust can be the largest contributor on 

some of the 20% haziest days, the RHR defines 

‘‘impairment’’ as anthropogenic impairment, and 

sulfate formed from anthropogenic SO2 emissions is 

the dominant contributor to anthropogenic 

visibility impairment on the haziest days. 

108The Grand Canyon Visibility Transport 

Commission Recommendations for Improving 

Western Vistas, June 10, 1996, p. 32. Available at 

http://www.wrapair.org/WRAP/reports/

GCVTCFinal.PDF and included in the docket. 

109 70 FR 39104, 39130 (July 6, 2005) (‘‘Other 

ways that visibility improvement may be assessed 

to inform the control decisions would be to 

examine distributions of the daily impacts, 

determine if the time of year is important (e.g. high 

impacts are occurring during tourist season), 

consideration of the cost-effectiveness of visibility 

improvements (i.e. the cost per change in deciview), 

using the measures of deciview improvement 

identified by the State, or simply compare the worst 

case days for the pre- and post-control runs. States 

may develop other methods as well.’’). 110 71 FR 60622 (Oct. 13, 2006). 

visibility benefits in all seasons.106 We 

also propose to find that, as concluded 

by the GCVTC, and supported by the 

IMPROVE monitoring data presented by 

Utah, anthropogenic visibility 

impairment on the Colorado Plateau is 

dominated by sulfates.107 108 Therefore, 

we propose to concur with Utah’s 

statement that sulfate is the largest 

contributor to visibility impairment at 

the affected Class I areas. 

We propose to disagree with the 

State’s findings related to park 

visitation. While the BART Guidelines 

do mention visitation as something that 

can inform a control decision,109 EPA is 

proposing to place little weight on the 

State’s correlation of emissions 

reductions and park visitation because 

nothing in the CAA suggests that 

visitors during busy time periods are 

entitled to experience better visibility 

than visitors during off-peak periods. 

On the contrary, in the Regional Haze 

provisions of the CAA, Congress 

declared a national goal of remedying 

all manmade visibility impairment in all 

class I areas, which includes both 

heavily-visited national parks and 

seldom-visited wilderness areas. We 

invite comment on our evaluation and 

the information and conclusions 

provided by Utah as summarized 

previously. 

viii. Energy and Non-Air Quality 

Benefits 

As discussed previously in section 

IV.C.5, the State noted that the Utah 

BART Alternative would avoid an 

annual energy penalty of approximately 

$2 million due to operating four SCR 

units at the Hunter and Huntington 

plants and presented additional non-air 

quality benefits associated with the 

closure of the Carbon plant such as 

waste reduction and decreased water 

usage. Because such benefits do not 

have direct bearing on whether the 

BART Alternative achieves greater 

reasonable progress, it is not material to 

our action whether we agree or disagree 

with Utah’s assessment that they reduce 

energy and non-air quality impacts. 

ix. Cost 

As discussed previously in section 

IV.C.5, the State noted that the Utah 

BART Alternative would achieve greater 

reasonable progress at lower cost to 

PacifiCorp than the BART Benchmark. 

Utah also noted that cost is one of the 

factors listed in CAA 169A(g)(2) that 

should be considered when determining 

BART. While we propose to find that 

the described cost difference does not 

have a direct bearing on whether the 

BART Alternative achieves greater 

reasonable progress, it is not material to 

our action whether we agree or disagree 

with Utah’s conclusion that the BART 

Alternative would have a lower cost 

impact to PacifiCorp than the BART 

Benchmark (i.e., costs provided by 

PacifiCorp in its BART analyses of 

August 5, 2014, SIP TSD Chapter 2). 

However, we do agree. 

f. Evaluation of the Weight of Evidence 

In accordance with our regulations 

governing BART alternatives, we 

support the use of a weight-of evidence 

determination as an alternative to the 

methodology set forth in section 

51.308(e)(3).110 In evaluating Utah’s 

weight-of-evidence demonstration, we 

have evaluated all nine elements of 

Utah’s analysis, and as discussed later, 

rely primarily on the following four 

elements in proposing to approve the 

BART Alternative: Annual emissions 

comparison for two pollutants; 

improvement in the number of days 

with significant visibility impairment; 

IMPROVE monitoring data regarding 

sulfates; and the early timing for 

installation of controls. Additional 

elements that either marginally support 

or do not support our proposed 

approval of Utah’s determination are 

also discussed later. 

Regarding the emissions reduction 

comparison, the Utah BART Alternative 

will result in 8,005 tpy fewer SO2

emissions compared to the BART 

Benchmark. In addition, the combined 

emissions of NOX, SO2 and PM10 will be 

2,856 tpy lower under the BART 

Alternative. 

Regarding the improvement in the 

number of days with significant 

visibility impairment, modeling 

submitted by Utah shows that the Utah 

BART Alternative will result in 

improved visibility at all affected Class 

I areas compared with baseline 

conditions. The units at issue will have 

impacts of 1.0 dv or more at the affected 

Class I areas on 48 fewer days under the 

Utah BART Alternative as compared to 

BART. When considering impacts of 0.5 

dv or more, the units at issue will 

impact the affected Class I areas on 154 

fewer days under the BART Alternative 

as compared to BART. 

Regarding the IMPROVE visibility 

monitoring data, we propose to agree 

with the State’s finding that SO2

emissions reductions provide visibility 

benefits throughout the year. We also 

propose to concur with Utah’s statement 

that sulfate is the largest contributor to 

visibility impairment at the affected 

Class I areas. 

Regarding the timing of emissions 

reductions, these SO2 emissions 

reductions were achieved in August 

2015, the date in the June 2015 Utah RH 

SIP requiring the closure of the Carbon 

plant. Combustion controls at the four 

BART units in addition to Hunter Unit 

3 were installed between 2006 and 

2014. BART likely would otherwise 

have been implemented sometime 

between 2019 and 2021. So the Utah 

BART Alternative provides early and 

on-going visibility benefits as compared 

to BART. 

Regarding other metrics that only 

marginally support or do not support 

our proposed approval of Utah’s BART 

Alternative, we propose to find that 

average annual dv impact and the 90th 

percentile impact are the two metrics 

that marginally support a conclusion 

that the BART Alternative achieves 

greater reasonable progress. 

Regarding the 98th percentile 

visibility impact, we propose to find 

this metric does not support our 

proposed approval of Utah’s BART 

Alternative. While the 98th percentile 

visibility impact is a key metric that 

EPA has primarily focused on in prior 

actions, we propose to conclude that by 

itself it is not a dispositive metric in 

weighing a BART Alternative. 

Nonetheless, as discussed in section VI, 

we have given considerable weight to 

this metric in previous actions where 

we have evaluated BART alternatives as 

it captures a source’s likely greatest 

visibility impacts at a Class I area; as 

such, it is a useful comparison point for 

determining whether one emission 

control scenario will have a greater 

impact on visibility improvement than 

another. In those actions, the 98th 

percentile visibility impact favored the 

BART alternative and therefore there 

was less need to introduce and consider 

additional evidence to determine 

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111 71 FR 60622 (Oct. 13, 2006). 112 40 CFR 51.308(e)(2)(iii). 

113See Memorandum from Lydia Wegman and 

Peter Tsirigotis, 2002 Base Year Emission Inventory 

SIP Planning: 8-hr Ozone, PM2.5, and Regional Haze 

Programs, November 18, 2002. http://www3.epa.

gov/ttnchie1/eidocs/2002baseinven_

102502new.pdf. 

114Regional Haze Section XX, N. (1). 

whether an alternative would provide 

greater reasonable progress. In the case 

of the Utah BART Alternative, where 

the 98th percentile does not favor the 

alternative, Utah has introduced 

additional evidence that we considered 

in order to evaluate whether the BART 

Alternative, on balance, achieves greater 

reasonable progress. 

Regarding the 90th percentile 

visibility impact, we propose to find 

that consideration of this metric is 

appropriate in assessing the weight of 

evidence associated with a BART 

alternative. Visibility at a Class I area 

changes from day to day, and each 

emission control scenario would result 

in visibility improvements at the 

affected Class I areas that would differ 

from one day to another. The metrics 

related to the number of days with 

impacts greater than 0.5 dv and 1.0 dv 

are examples of the type of additional 

information that allows for 

consideration of the frequency and 

duration of visibility impacts. Similarly, 

the use of the 90th percentile impact 

metric allows for the comparison of 

BART and a BART alternative at a 

different point in the range of impacts. 

This can be useful, given the varying 

impacts of different pollutants under 

different meteorological conditions. The 

information provided by Utah for the 

90th percentile shows that the BART 

Alternative is better at seven of the nine 

Class I areas for this metric, by amounts 

ranging from 0.019 to 0.140 dv, and is 

better when taking into account the 

impacts averaged both across three years 

and across nine Class I areas, but only 

by 0.006 dv. These values marginally 

support our proposed approval of Utah’s 

BART Alternative as better than BART. 

We invite comment on this proposed 

assessment of how the 90th percentile 

metric should be considered in the 

weight of evidence determination. We 

also invite interested parties to submit 

additional information on how the 

impacts of the BART Alternative under 

various conditions compare to the 

impacts of the presumed BART 

scenario, because while the 90th 

percentile impact provides additional 

insight, it is not uniquely informative. 

Regarding the energy and non-air 

quality impacts, as well as cost, we 

propose to find these metrics do not 

have direct bearing on whether the Utah 

BART Alternative achieves greater 

reasonable progress than the BART 

Benchmark; and therefore, we have not 

taken them into consideration. 

Consistent with EPA’s regulations 

governing BART alternatives,111 in 

evaluating the weight-of-evidence 

demonstration, we have evaluated all of 

the information and data submitted by 

Utah, while recognizing the relative 

strengths and weaknesses of that 

information to arrive at our proposed 

decision. Based on the weight-ofevidence presented, we propose to 

approve Utah’s determination that the 

Utah BART Alternative would achieve 

greater reasonable progress than BART 

under 40 CFR 51.308(e)(2)(i)(I). 

g. Requirement That Emission 

Reductions Take Place During Period of 

First Long-Term Strategy 

As discussed previously in section 

IV.C.6, pursuant to 40 CFR 

51.308(e)(2)(iii), the State must ensure 

that all necessary emission reductions 

take place during the period of the first 

long-term strategy for regional haze, i.e., 

by December 31, 2018. The RHR further 

provides that, to meet this requirement, 

the State must provide a detailed 

description of the alternative measure, 

including schedules for 

implementation, the emission 

reductions required by the program, all 

necessary administrative and technical 

procedures for implementing the 

program, rules for accounting and 

monitoring emissions, and procedures 

for enforcement.112

As noted previously, the Utah SIP 

revision incorporates the revisions to 

R307–110–17, Section IX, Control 

Measures for Area and Point Sources, 

Part H, Emissions Limits, which 

includes provisions for implementing 

the Utah BART Alternative. In addition 

to the emission limitations for NOX and 

PM10, and the requirement for shutdown 

of the Carbon plant listed in Table 2, the 

SIP includes compliance dates, 

operation and maintenance 

requirements, and monitoring, 

recordkeeping, and reporting 

requirements. We propose to find that 

these provisions meet the requirements 

of 40 CFR 51.308(e)(2)(iii). 

h. Demonstration That Emission 

Reductions From Alternative Program 

Will Be Surplus 

i. June 2015 Utah RH SIP 

As discussed previously in section 

IV.C.7, pursuant to 40 CFR 

51.308(e)(2)(iv), the SIP must 

demonstrate that the emissions 

reductions resulting from the alternative 

measure will be surplus to those 

reductions resulting from measures 

adopted to meet requirements of the 

CAA as of the baseline date of the SIP. 

The baseline date for regional haze SIPs 

is 2002.113 As discussed in section 

IV.C.7, all of the emission reductions 

required by the Utah BART Alternative 

result from measures applicable to 

Hunter, Huntington and Carbon that 

occur after 2002. 

Furthermore, the State’s SIP explains 

that the WRAP modeling that was done 

to support the Utah RH SIP included 

regional SO2 emissions based on the 

2018 SO2 milestone and also included 

NOX and PM10 emissions from the 

Carbon plant. Thus, WRAP did not rely 

on emission reductions from the Carbon 

plant in establishing the 2018 SO2

milestone. 

The State’s SIP also includes SO2

trend data that further demonstrate 

emission reductions from the Carbon 

plant do not appear to be needed for 

meeting the 2018 milestone of 141,849 

tpy. Actual emissions in the three-state 

region are calculated each year and 

compared to the milestones. As can be 

seen in Table 7, SO2 emissions reported 

for 2011 are below the 2018 milestone 

and the most recent milestone report for 

2013 demonstrates that SO2 emissions 

are currently 26 percent lower than the 

2018 milestone. Additionally, the 

Carbon plant was fully operational in 

the years 2011–2013 when the 

emissions from the three-state region 

were below the 2018 milestone for those 

years. Therefore, the SO2 emission 

reductions from the closure of the 

Carbon plant appear to be surplus to 

what is needed to meet the 2018 

milestone established in Utah’s RH SIP. 

ii. October 2015 Utah RH SIP 

As discussed previously in section 

IV.D, Utah submitted enforceable 

commitments in its October 20, 2015 

SIP to address potential concerns that 

the State would be double counting SO2

emissions reductions for the Carbon 

plant closure under both the 40 CFR 

51.308 and 309 programs.114

EPA has historically recognized that 

under certain circumstances, it is 

appropriate to approve a SIP submission 

that consists, in part, of an enforceable 

commitment. Once EPA determines that 

circumstances warrant consideration of 

an enforceable commitment to meet 

section 110(a)(2)(A) of the Act (and 

other applicable sections as relevant), 

EPA applies three factors to determine 

whether to approve the enforceable 

commitment: (1) Whether the 

commitment addresses a limited portion 

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115Regional Haze SIP Section XX, N. (1). 

116Regional Haze SIP Section XX, N. (4). 

117Regional Haze SIP Section XX, N. (4). 

118Regional Haze SIP Section XX, N. (3). 

119Regional Haze SIP Section XX, N. (6), (3). 

120Regional Haze SIP Section XX, N. (2). 

121 40 CFR 51, appendix Y, section IV.D.1.9. 

122 June 2015 Utah RH SIP, Sections 

IX.H.22.a.i.A–B, IX.H.22.b.i.A–B. 

123 40 CFR 51.212(c). 124Letter from Department of Environmental 

Quality, State of Utah to EPA, DAQP–120–15 (Dec. 

10, 2015). 125 77 FR 57864; 79 FR 5032. 126 77 FR 74365–74366 (Dec. 14, 2012). 

of the statutorily-required program; (2) 

whether the state is capable of fulfilling 

its commitment; and (3) whether the 

commitment is for a reasonable and 

appropriate period of time. Once 

approved in a SIP, the commitments are 

enforceable by both EPA and citizens 

under the Act. 

First, Utah’s revisions address a 

limited portion of the statutorilyrequired program. The Air Quality 

Board adopted revisions to SIP Section 

XX, Regional Haze, and added a new 

subsection N, ‘‘Enforceable 

Commitments for the Utah Regional 

Haze SIP’’ that resolves specific 

identified issues. In this provision of the 

SIP, ‘‘[t]he State commits to resolving 

this double counting issue by revising 

the Utah 309 plan to specifically state 

that the 8,005 tons of SO2 emissions 

from the Carbon units will be added 

into the annual milestone reports from 

2016 through the life of the backstop 

trading program, thereby removing any 

credit for that emission reduction in 

meeting the levels specified in the Utah 

309 plan.’’ 115 Reporting Carbon’s 

emissions in this manner is reasonable 

and ensures that these emissions 

reductions are only credited under the 

BART Alternative. 

The SIP indicates the Board is capable 

of fulfilling these commitments by 

explaining that ‘‘[a]ll required 

amendments to this SIP will be done 

through the State’s SIP adoption 

process’’ 116 and that ‘‘[t]he SIP is 

adopted by the Governor-appointed Air 

Quality Board through a rulemaking 

process that includes public comment 

periods and an opportunity for a public 

hearing.’’ 117

The SIP commits to resolve the 

identified issues (‘‘SIP Section XX.D.3.c 

and [the State’s rule] R307–150 will be 

revised . . .’’ 118), and any other related 

issues, within reasonable amount of 

time (‘‘Utah will work with EPA and 

take appropriate action to resolve any 

completeness or approvability issues 

that arise regarding the proposed SIP 

revision by March 2018’’ 119). This will 

allow sufficient time for EPA to act on 

the submittal before the end of the 

milestone commitment. 

We also propose to concur that 

Carbon’s 8,005 tpy of SO2 emissions 

reductions is a limited portion of the 

overall requirements of the 309 program 

and particularly in comparison to the 

2018 SO2 milestone of 141,849 tpy 

described in Table 7.120

Based on these considerations, we 

propose to approve the enforceable 

commitment SIP. 

Therefore, based on the information 

presented previously from the State’s 

SIP and enforceable commitment SIP, 

we propose to concur that the 

reductions from Carbon are surplus and 

can be considered as part of an 

alternative strategy under 40 CFR 

51.308(e)(2)(iv). 

C. PM10 BART Determinations 

As discussed previously in section 

IV.B.2, Utah determined that the PM10

BART emission limit for Hunter Units 1 

and 2 and Huntington Units 1 and 2 was 

0.015 lb/MMBtu based on a three-run 

test average. Utah noted that because the 

most stringent technology is in place at 

these units and that the PM10 emission 

limits have been made enforceable in 

the SIP, no further analysis was 

required. 

EPA has reviewed Utah’s PM10 BART 

streamlined five-factor analysis and 

PM10 BART determinations for Hunter 

Units 1 and 2 and Huntington Units 1 

and 2 and proposes to find that these 

determinations meet the requirements of 

40 CFR 51.309(d)(4)(vii). The fabric 

filter baghouses installed at these BART 

units are considered the most stringent 

technology available. The emission limit 

of 0.015 lb/MMBtu at these units 

represents the most stringent emission 

limit for PM10. Utah’s use of a 

streamlined approach to the five-factor 

analysis is reasonable as the BART 

Guidelines provide that a 

comprehensive BART analysis can be 

avoided if a source commits to a BART 

determination that consists of the most 

stringent controls available.121

Utah’s regulatory text provides, 

‘‘[e]missions of particulate (PM) shall 

not exceed 0.015 lb/MMBtu heat input 

from each boiler based on a 3-run test 

average.’’ It further states that ‘‘[s]tack 

testing for the emission limitation shall 

be performed each year on each 

boiler.’’ 122 We note that BART limits 

must apply at all times. See CAA 

section 302(k), 40 CFR part 51, 

appendix Y, section V. Furthermore, 

EPA’s credible evidence rule requires 

that a state’s plan must not preclude the 

use of any credible evidence or 

information, which can include 

evidence and information other than the 

test method specified in the plan, that 

would indicate whether a source was in 

compliance with applicable 

requirements.123

Consistent with these requirements, 

we propose to interpret Utah’s 

regulatory text as imposing a PM limit 

of 0.015 lb/MMBtu that applies at all 

times and does not preclude the use, 

including the exclusive use, of any 

credible evidence or information, 

relevant to whether a source is in 

compliance with the limit. 

D. Monitoring, Recordkeeping, and 

Reporting 

EPA has reviewed Utah’s monitoring, 

recordkeeping and reporting measures 

in its June 4, 2015 SIP Section IX, Part 

H for the BART Alternative and the 

PM10 BART determinations and 

proposes to approve these measures as 

meeting the requirements of section 

110(a)(2) of the CAA and 40 CFR 51, 

subpart K, Source Surveillance, with the 

exception of reporting requirements for 

violations of PM10 emissions 

limitations. For PM10 reporting, we are 

proposing to conditionally approve this 

element in accordance with CAA 

section 110(k)(4) based on Utah’s 

commitment to submit specific 

measures to address the reporting 

requirement.124 Utah’s letter commits to 

adopt and submit rule language that 

would require sources to report any 

deviation from the requirements of the 

RH SIP provisions, which would 

include the PM10 emission limitations. 

The specific language is detailed in 

Utah’s commitment letter. 

Otherwise, the SIP includes adequate 

measures that pertain to operation of 

Hunter and Huntington and the closure 

of Carbon. EPA previously approved 

state rule provisions that Utah has also 

cross referenced in these new regional 

haze measures, including terms, 

conditions and definitions in R307– 

101–1, R307–101–2 and R307–170–4 as 

well as other continuous emission 

monitoring system (CEMS) requirements 

referenced in R307–107. These 

measures are consistent with similar 

monitoring, recordkeeping, and 

reporting requirements that EPA has 

approved in other states or that we have 

adopted in federal plans,125 and in 

particular contain the requirements that 

were missing from Utah’s prior regional 

haze submittals.126 As described 

previously in section IV.A.3, Utah has 

provided the emission limitations, work 

practice standards, monitoring, 

recordkeeping, and reporting 

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127See Memorandum from John Calcagni to EPA 

Regional Directors. ‘‘Processing of State 

Implementation Plan (SIP) Submittals’’ (July 1992), 

available at http://www3.epa.gov/ttn/oarpg/t1/

memoranda/siproc.pdf. 

128 40 CFR 51.308(e)(2)(i). 

129 40 CFR 51.308(e)(2)(iii). 

130 40 CFR 51.308(e)(2)(iv). 

131As presented in this proposal, while the 

majority of the State’s demonstration is contained 

in Chapter 1, EPA has identified additional 

information regarding the demonstration and we 

include references to the additional information. 

132 77 FR 74357 (Dec. 14, 2012). 

requirements for all the units that are 

part of Utah’s BART Alternative for the 

Hunter, Huntington, and Carbon plants. 

If we finalize our proposed approval, 

the regulatory text contained in our final 

rule for 40 CFR part 52 subpart TT will 

be consistent with the relevant 

provisions of Utah’s regional haze 

submittals for making the emission 

limits and other requirements 

enforceable. If EPA finalizes the 

conditional approval of Utah’s PM10

reporting provision, the State has one 

year from the date of EPA’s final action 

on the June 4, 2015 SIP to submit the 

necessary SIP revisions. If the State fails 

to meet its commitment within the oneyear period, the approval is treated as a 

disapproval. EPA proposes to find that 

the necessary SIP revisions meet EPA’s 

criteria for conditional approvals 127 as 

the revisions appear to involve a limited 

amount of technical work, are 

anticipated to be non-controversial, and 

can reasonably be accomplished within 

the length of time for the State’s 

adoption process. 

E. Consultation with FLMs 

As discussed previously in section 

IV.G, Utah conducted FLM consultation 

during late 2014, providing over 60 days 

prior to the December 1, 2014 public 

hearing. Subsequently, the National 

Park Service provided extensive 

comments in response to a second 

public comment period in April 2015. 

Based on these considerations, we 

propose to find that Utah has met the 

requirements of 40 CFR 308(i)(2). 

VI. EPA’s Evaluation and Proposed 

Partial Approval and Partial 

Disapproval of Utah’s Regional Haze 

SIP 

In this section, we present the second 

of two alternative proposed actions on 

which EPA is soliciting comment. As 

explained previously in sections II.A 

and V, EPA is soliciting comments on 

two alternative proposals: a proposal to 

approve the State SIP in its entirety, and 

a proposal to partially approve and 

partially disapprove the State SIP and to 

issue a FIP. The co-proposals detailed in 

this section and Section V represent 

different conclusions regarding Utah’s 

NOX BART Alternative and the metrics 

the State has proposed to support this 

alternative. 

As described in this section, EPA is 

proposing to partially approve and 

partially disapprove Utah’s June 2015 

and October 2015 RH SIP revisions and 

propose a FIP. Alternatively, as 

discussed in section V, EPA is coproposing in the alternative to approve 

Utah’s June 2015 and October 2015 RH 

SIP revisions. 

This document is written as two 

separate proposals in order to clearly 

present the options and solicit comment 

on each. EPA intends to finalize only 

one of these co-proposals; however, we 

also acknowledge that additional 

information and comments may also 

lead the Agency to adopt final SIP and/ 

or FIP regulations that differ somewhat 

from the co-proposals presented here 

regarding the BART Alternative, BART 

control technology option or emission 

limits, or impact other proposed 

regulatory provisions. 

A. Basis for Proposed Partial 

Disapproval and Partial Approval 

For the reasons described later, EPA 

proposes to partially approve and 

partially disapprove the two Utah 2015 

RH SIP revisions. Our proposed action 

is based on an evaluation of Utah’s 

regional haze SIP submittals against the 

regional haze requirements at 40 CFR 

51.300–51.309 and CAA sections 169A 

and 169B, as well as the supplemental 

information EPA developed, such as 

EPA’s calculations of the visibility 

improvements for each modeling 

scenario using consistent meteorological 

years in evaluating the 98th percentile 

modeling and referencing the 

topographical maps in evaluating 

whether distribution of emissions 

would be substantially different under 

the Utah BART Alternative. All general 

SIP requirements contained in CAA 

section 110, other provisions of the 

CAA, and our regulations applicable to 

this action were also evaluated. The 

purpose of this action is to ensure 

compliance with these requirements. As 

discussed in section V, EPA is also coproposing to approve the Utah’s June 

2015 and October 2015 RH SIP 

revisions. 

B. Utah BART Alternative 

1. Summary of Utah BART Alternative 

Utah has opted to establish an 

alternative measure (or program) for 

NOX in accordance with 40 CFR 

51.308(e)(2). A description of the Utah 

BART Alternative is provided in section 

IV.C. The RHR requires that a SIP 

revision establishing a BART alternative 

include three elements as listed later. 

We have evaluated the Utah BART 

Alternative with respect to each of these 

elements. 

• A demonstration that the emissions 

trading program or other alternative 

measure will achieve greater reasonable 

progress than would have resulted from 

the installation and operation of BART 

at all sources subject to BART in the 

State and covered by the alternative 

program.128

• A requirement that all necessary 

emissions reductions take place during 

the period of the first long-term strategy 

for regional haze.129

• A demonstration that the emissions 

reductions resulting from the alternative 

measure will be surplus to those 

reductions resulting from measures 

adopted to meet requirements of the 

CAA as of the baseline date of the 

SIP.130

2. Demonstration of Greater Reasonable 

Progress for Alternative Program 

As discussed previously in section 

III.E.1, pursuant to 40 CFR 

51.308(e)(2)(i), Utah must demonstrate 

that the alternative measure will achieve 

greater reasonable progress than would 

have resulted from the installation and 

operation of BART at all sources subject 

to BART in the State and covered by the 

alternative program. This 

demonstration, primarily included in 

Chapter 1 of the TSD of the Utah RH 

SIP,131 must be based on five criteria 

presented below. 

a. A List of All BART-Eligible Sources 

Within the State 

As discussed previously in section 

IV.C.1, Utah included a list of BARTeligible sources and noted the following 

sources are all covered by the 

alternative program: 

• PacifiCorp Hunter, Unit 1, 

• PacifiCorp Hunter, Unit 2, 

• PacifiCorp, Huntington, Unit 1, and 

• PacifiCorp, Huntington, Unit 2. 

EPA approved Utah’s BART eligibility 

determinations in our 2012 

rulemaking.132

b. A List of All BART-Eligible Sources 

and All BART Source Categories 

Covered by the Alternative Program 

As discussed previously in section 

IV.A.3, the Utah BART Alternative 

covers all the BART-eligible sources in 

the state, Hunter Units 1 and 2 and 

Huntington Units 1 and 2, in addition 

to three non-BART units, PacifiCorp’s 

Hunter Unit 3 and Carbon Units 1 and 

2. EPA previously approved Utah’s 

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133 77 FR 74357 (Dec. 14, 2012). 

134 40 CFR 51, appendix Y, section IV.D.1.9. 

135 79 FR 9318, 9335 (Feb. 18, 2014). 

136 79 FR 9318, 9335 (Feb. 18, 2014). See, e.g., 77 

FR 11827, 11837 (Feb. 28, 2012) (proposed approval 

of Maryland BART Alternative, which shows 

greater SO2 and NOX reductions from the 

Alternative than application of BART, the two 

pollutants covered by the Alternative); 77 FR 39938, 

39940–1 (July 6, 2012) (final approval of Maryland 

BART Alternative, explaining in responding to 

comments that because the emission reductions are 

greater for the Alternative than BART and the 

distribution of emissions is not substantially 

different, the Alternative was found to meet 40 CFR 

51.308(e)(2) and visibility dispersion modeling was 

not needed). 

137 79 FR 9318, 9335 (Feb. 18, 2014) (proposed 

approval of Arizona BART Alternative for Sundt 

Unit 4). See also, 79 FR 52420 (Sept. 3, 2014) (final 

approval of Arizona BART Alternative for Sundt 

Unit 4); 77 FR 18052, 18073–18075 (Mar. 26, 2012) 

(proposed approval of Colorado BART Alternative, 

no modeling required where the 40 CFR 

51.308(e)(3) test was met); 77 FR 76871 (Dec. 31, 

2012) (final approval of Colorado BART 

Alternative). 

138 80 FR 19220, 19221 (Apr. 10, 2015). See, e.g., 

79 FR 56322, 56327–28 (Sept. 19, 2014); 77 FR 

18052, 18075 (Mar. 26. 2012). 

139 77 FR 18052, 18075 (Mar. 26, 2012). 

140 79 FR 56322, 56328 (Sept. 19, 2014) (proposed 

approval of Arizona Apache BART Alternative); 80 

FR 19220 (Apr. 10, 2015) (final approval of Arizona 

Apache BART Alternative). 

141 79 FR 33438, 33441 (June 11, 2014) (final rule, 

FIP for Tesoro Refining BART Alternative); See, 

e.g., 79 FR 56322, 56328 (Sept. 19, 2014) (proposed 

approval of Arizona Apache BART Alternative); 80 

FR 19220 (Apr. 10, 2015) (final approval of Arizona 

Apache BART Alternative); 77 FR 11827, 11837 

(Feb. 28, 2012) (proposed approval of Maryland 

BART Alternative); 77 FR 39938, 39940–1 (July 6, 

2012) (final approval of Maryland BART 

Alternative). 

142 79 FR 9318, 9335 (Feb. 18, 2014)(proposed 

approval of Arizona BART Alternative for Sundt 

Unit 4). 79 FR 52420 (Sept. 3, 2014) (final approval 

of Arizona BART Alternative for Sundt Unit 4); 77 

FR 18052, 18073–18075 (Mar. 26, 2012) (proposed 

approval of Colorado BART Alternative, no 

modeling required where the 40 CFR 51.308(e)(3) 

test was met); 77 FR 76871 (Dec. 31, 2012) (final 

approval of Colorado BART Alternative). 

BART eligibility determinations in our 

2012 rulemaking.133

c. Analysis of BART and Associated 

Emission Reductions Achievable 

As noted previously in section IV.C.3, 

in the June 2015 Utah RH SIP, Utah 

compared the Utah BART Alternative to 

a BART Benchmark which included the 

most stringent NOX BART controls, SCR 

plus new LNBs and SOFA, at the four 

BART units. This is consistent with the 

streamlined approach described in Step 

1 of the BART Guidelines. The BART 

Guidelines note that a comprehensive 

BART analysis can be avoided if a 

source commits to a BART 

determination that consists of the most 

stringent controls available.134

We propose to find that Utah has met 

the requirement for an analysis of BART 

and associated emission reductions 

achievable at Hunter and Huntington 

under 40 CFR 51.308(e)(2)(i)(C). 

d. Analysis of Projected Emissions 

Reductions Achievable Through the 

BART Alternative 

As discussed previously in section 

IV.C.4, a summary of Utah’s estimates of 

emissions for the Utah BART 

Alternative and the BART Benchmark is 

provided in Table 3. We propose to find 

that Utah has met the requirement for an 

analysis of the projected emissions 

reductions achievable through the 

alternative measure under 40 CFR 

51.308(e)(2)(i)(D). 

e. A Determination That the Alternative 

Achieves Greater Reasonable Progress 

Than Would Be Achieved Through the 

Installation and Operation of BART 

Greater Reasonable Progress Based on 

40 CFR 51.308(e)(3)’s Greater Emission 

Reductions Test 

As discussed previously in section 

III.E.1, 40 CFR 51.308(e)(3) allows a 

state to satisfy the final step of the 

better-than-BART demonstration by 

showing that that ‘‘distribution of 

emissions is not substantially different 

than under BART’’ and that ‘‘the 

alternative measure results in greater 

emission reductions.’’ EPA has 

explained that when the BART 

alternative ‘‘achieves greater emission 

reductions than each of the individual 

BART determinations’’ 135 for each of 

the pollutants, ‘‘as well as in the 

aggregate,’’ 136 ‘‘visibility modeling is 

not required to support a better-thanBART determination. . . .’’ 137

However, as EPA explained in 

responding to comments in the final 

rule for the BART Alternative for the 

Apache Generating Station in Arizona’s 

SIP, ‘‘where BART and the BART 

Alternative result in reduced emissions 

of one pollutant but increased emissions 

of another, it is not appropriate to use 

the ‘greater emission reductions’ test.’’ 

Instead, the proper approach is to 

employ a clear weight-of-evidence 

approach under 40 CFR 51.308(e)(2) in 

order to demonstrate that the alternative 

achieves greater reasonable progress 

than BART.’’ 138 We have not 

considered a total emissions profile that 

combines emissions of multiple 

pollutants to determine whether BART 

or the alternative is ‘‘better,’’ except 

where every visibility impairing 

pollutant is reduced by a greater amount 

under the BART alternative.139 A 

comparison of mass emissions from 

multiple pollutants (such as NOX and 

SO2) is not generally informative, 

particularly in assessing whether the 

alternative approach provides for greater 

reasonable progress towards improving 

visibility. Instead, when emissions of 

one or more pollutants increases under 

an alternative, EPA has ‘‘given the most 

weight to the visibility impacts based on 

air quality modeling’’ 140 and used 

modeling to determine whether or not a 

‘‘BART Alternative measure that relies 

on interpollutant trading results in 

greater reasonable progress.’’ 141

The State’s demonstration appears to 

satisfy the first part of the test under 40 

CFR 51.308(e)(3) (the distribution of 

emissions may not be substantially 

different than under BART) since the 

Hunter, Huntington and Carbon plants 

are all located within close proximity of 

each other in central Utah, as discussed 

previously in section IV.C.5. EPA’s 

interpretation of the requirement under 

40 CFR 51.308(e)(3) that the alternative 

measure ‘‘results in greater emission 

reductions’’ has been that the emission 

reduction comparisons are pollutant 

specific. We have not looked at a total 

emissions profile that combines 

emissions of multiple pollutants to 

determine whether a BART benchmark 

or a BART alternative is ‘‘better,’’ except 

where every visibility impairing 

pollutant is reduced by a greater amount 

under the BART alternative.142

Therefore, we propose to find that the 

State’s demonstration does not meet the 

second part of the test. While in the 

aggregate there are fewer SO2 and PM10

emissions for the BART Alternative, the 

total NOX emissions are greater under 

the BART Alternative than the BART 

Benchmark. Therefore, we propose to 

disapprove Section XX.D.6.c of the Utah 

SIP under the test in 40 CFR 

51.308(e)(3). 

Greater Reasonable Progress Based on 

40 CFR 51.308(e)(2)’s Weight-ofEvidence Test 

Utah also chose to conduct a weightof-evidence analysis under 40 CFR 

51.308(e)(2) based on a BART 

Alternative involving certain units at 

the Hunter, Huntington, and Carbon 

power plants, which included the 

following nine categories of evidence. 

i. Annual Emissions Comparison of all 

Visibility-Impairing Pollutants 

The emissions of visibility-impairing 

pollutants from both the Utah BART 

Alternative and the BART Benchmark, 

as estimated by Utah, are summarized in 

Table 3 in section IV.C.4. Compared 

with the Utah BART Benchmark, the 

State projects that the Utah BART 

Alternative will result in 5,721 tpy more 

NOX emissions, 8,005 tpy fewer SO2

emissions and 573 tpy fewer PM10

emissions than the BART Benchmark. 

As discussed previously, Utah also 

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143 79 FR 9318, 9335 (Feb. 18, 2014) (proposed 

approval of Arizona BART Alternative for Sundt 

Unit 4). 79 FR 52420 (Sept. 3, 2014) (final approval 

of Arizona BART Alternative for Sundt Unit 4); 77 

FR 18052, 18073–18075 (Mar. 26, 2012) (proposed 

approval of Colorado BART Alternative, no 

modeling required where the 40 CFR 51.308(e)(3) 

test was met); 77 FR 76871 (Dec. 31, 2012) (final 

approval of Colorado BART Alternative). 

144 64 FR 35714, 35743 (July 1, 1999). 

145 78 FR 79344, 79355 (Dec. 30, 2013). 

146 79 FR 33438, 33440 (June 11, 2014). 

147 40 CFR 51, appendix Y, section IV.D.5. 

148 70 FR 39130 (July 6, 2005). 

noted that the combined emissions of 

NOX, SO2 and PM10 will be 2,856 tpy 

lower under the BART Alternative than 

the BART Benchmark. 

While the total emission reductions 

under the Utah BART Alternative are 

less than those under the BART 

Benchmark, a comparison of emissions 

of multiple pollutant species of 

emissions is generally not informative, 

particularly when the Agency is 

assessing whether an approach provides 

for greater reasonable progress towards 

improving visibility. As explained in 

section VI.B.e, our interpretation of the 

language in 40 CFR 51.308(e)(3) 

(‘‘results in greater emission reductions 

. . . may be deemed to achieve greater 

reasonable progress’’) has been pollutant 

specific. EPA has not relied on a total 

emissions profile that combines 

emissions of multiple pollutants 

together to determine that either BART 

or a BART alternative is ‘‘better,’’ 

because visibility modeling is the most 

appropriate method to assess the overall 

improvements in visibility impacts from 

control scenarios where reductions of 

multiple pollutants are considered, 

except where every visibility impairing 

pollutant is reduced by a greater amount 

under the alternative.143 As we have 

explained, ‘‘[e]ach of the five pollutants 

which cause or contribute to visibility 

impairment has a different impact on 

light extinction for a given particle 

mass, making it therefore extremely 

difficult to judge the equivalence of 

interpollutant trades in a manner that 

would be technically credible, yet 

convenient to implement in the 

timeframe needed for transactions to be 

efficient. This analysis is further 

complicated by the fact that the 

visibility impact that each pollutant can 

have varies with humidity, so that 

control of different pollutants can have 

markedly different effects on visibility 

in different geographic areas and at 

different times of the year.’’ 144 As other 

Agency actions on BART alternatives 

have explained, modeling assesses 

‘‘both pollutants’ chemical aerosol 

formation mechanisms and impacts on 

visibility,’’ 145 which allows evaluation 

of the ‘‘relative visibility impacts from 

the atmospheric formation of visibility 

impairing aerosols of sulfate and 

nitrate.’’ 146 Since we find that Utah’s 

BART Alternative provides greater 

emission reductions for two pollutants 

(SO2 and PM10), but find that NOX

emissions would be greater under the 

BART Alternative, we propose to find 

that it is not appropriate to combine all 

three pollutants in the annual emissions 

comparison test to support the BART 

Alternative as the State has done. While 

we acknowledge that two of the 

pollutants are less under the BART 

Alternative, one of the pollutants is 

greater, therefore we further propose to 

find that the annual emissions 

comparison of all three pollutants does 

not show that the BART Alternative is 

better than the BART Benchmark. 

ii. Improvement in the Number of Days 

With Significant Visibility Impairment 

As discussed previously in section 

IV.C.5, Utah provided modeling results 

to assess the improvement in the 

number of days with significant 

visibility impairment—that is, the 

improvement in the number of days 

with impacts that either cause (>1.0 dv) 

or contribute (0.5 dv) to visibility 

impairment. 

The BART Guidelines provide that, 

when making a BART determination, a 

State may consider the number of days 

or hours that a threshold was 

exceeded.147 In developing the BART 

Guidelines, our example modeling 

analysis of a hypothetical source 

examined the number of days that 1.0 

dv and 0.5 dv thresholds were 

exceeded.148 As detailed in section 

IV.C.5.b, we note the difference in the 

total number of days impacted—18 

fewer days greater than the causation 

threshold of 1.0 dv (775 days for the 

BART Alternative vs. 793 days for the 

BART Benchmark), and 175 fewer days 

greater than the contribution 0.5 dv 

threshold (1,323 days for the BART 

Alternative vs. 1,498 days for the BART 

Benchmark. Utah’s results show that 

there are fewer days with impacts over 

0.5 dv for the BART Alternative, which 

indicates greater improvement in 

visibility. Therefore, the results for the 

0.5 dv threshold favor the BART 

Alternative. 

However, Utah’s results for the total 

number of days with impacts over 1.0 

dv on a Class I area-by-area basis are not 

as clear in supporting the BART 

Alternative. The modeling results for 

the total number of days with impacts 

greater than 1.0 dv show that the BART 

Alternative would have more days with 

impacts greater than 1.0 dv at seven of 

the nine Class I areas, and that only two 

of the Class I areas, would have fewer 

days with impacts greater than 1.0 dv 

compared to the BART Benchmark. 

Therefore, the Class I area-by-area 

results do not show that the BART 

Alternative is better than the BART 

Benchmark. Similarly, the results for the 

average number of days with impacts 

over 1.0 dv show that most of the Class 

I areas have the same result under both 

the BART Alternative and Benchmark, 

or are within one day of having the 

same result. In this context, a difference 

of one day is not particularly significant. 

We therefore propose to find that these 

results do not show the BART 

Alternative is better. 

Utah’s results in applying the number 

of days with impacts greater than 1.0 dv 

show the BART Alternative is better ‘‘on 

average’’ across all nine Class I areas. 

We agree that use of average visibility 

impacts could be acceptable as part of 

assessing the multiple-area impacts and 

improvements. However, in this case 

the visibility results for the individual 

Class I areas do not consistently support 

or undermine the BART Alternative; 

there is variation by Class I area. Here, 

averaging the visibility results has the 

effect of obscuring the impacts on the 

individual Class I areas. Additionally, 

we propose to not the give the 

difference in days significant weight 

because by itself it does not indicate 

whether benefits on those days were 

large or small. Therefore, while we note 

that the BART Alternative shows fewer 

days with impacts greater than 1.0 dv 

when looking at the average over all 

nine areas, we propose to find that 

averaging the number of days with 

impacts greater than 1.0 dv across all 

affected Class I areas is not a relevant 

metric under these circumstances. We 

therefore further propose to find that 

this metric does not show the BART 

Alternative is better. 

iii. 98th Percentile Impact (dv) 

As discussed previously in section 

IV.C.5, Utah asserted that the only 

metric it evaluated that showed greater 

improvement for the BART Benchmark 

in comparison to the BART Alternative 

was the 98th percentile metric when 

averaged across all Class I areas and 

meteorological years modeled. Utah’s 

comparison of the modeled visibility 

impacts on the 98th percentile day (8th 

highest impacted day in a given 

meteorological year) for the most 

impacted year shows that the BART 

Benchmark would result in greater 

visibility improvement at five of the 

nine Class I areas, and is better on 

average across all nine Class I areas 

(0.11 dv difference). At the most 

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149 40 CFR 51, appendix Y, section IV.D.5. 

150 70 FR at 39129. 

151See, e.g., 78 FR 79344 (Dec. 30, 

2012)(proposed rule, FIP for Tesoro Refining and 

Intalco Refinery BART Alternatives); 79 FR 33438 

(June 11, 2014)(final rule, FIP for Tesoro Refining 

and Intalco Refinery BART Alternatives); 79 FR 

56322, 56328 (Sept. 19, 2014)(proposed approval of 

Arizona Apache BART Alternative); 80 FR 19220 

(Apr. 10, 2015)(final approval of Arizona Apache 

BART Alternative); 77 FR 11827, 11837 (Feb. 28, 

2012)(proposed approval of Maryland BART 

Alternative); 77 FR 39938, 39940–1 (July 6, 

2012)(final approval of Maryland BART 

Alternative). 

152See EPA Calculation of 98th Percentile 

Improvement for Utah Bart Alternative spreadsheet 

(in docket). 

153 Id. 

154 Id. 

155 Id. 

156EPA final actions on BART Alternatives that 

evaluated CALPUFF modeling analysis, which did 

not include consideration of annual average dv 

impacts include: 80 FR 19220 (Apr. 10, 

2015)(Region 9, Apache); 79 FR 33438 (June 11, 

2014)(Region 10, Tesoro Refining and Alcoa Intalco 

Operations); 77 FR 39938 (July 6, 2012)(Region 3, 

Maryland HAA). 

157See Utah Regional Haze State Implementation 

Plan, Technical Support Document, Ch. 1, p. 23 

(2015). 

158 70 FR 39121 (July 5, 2005). 

159Copies of Administrative Orders DAQE– 

AN0102370012–08 and DAQE–AN0102380021–10 

are included in the docket, and include information 

regarding the schedule for installation of 

combustion controls at Hunter and Huntington. 

impacted Class I areas, Canyonlands 

and Capitol Reef, Utah found that the 

98th percentile metric indicates the 

BART Benchmark has 0.76 dv and 0.57 

dv, respectively, more improvement 

than the BART Alternative. At other 

Class I areas, such as Arches, Utah 

found that the 98th percentile metric 

indicates that the BART Alternative 

provides greater visibility improvement 

(for example, 0.44 dv at Flat Tops). 

The 98th percentile visibility impact 

is a key metric recommended by the 

BART Guidelines when selecting BART 

controls.149 As noted previously, we 

described this metric as an appropriate 

measure for determining the degree of 

visibility improvement to be expected 

from controls.150 In addition, this is one 

of the primary metrics that EPA has 

relied on in evaluating prior regional 

haze actions that have included BART 

alternatives.151

We note that when calculating 

visibility improvements for individual 

Class I areas, Utah mixed the impacts 

from different meteorological years 

between modeling scenarios (baseline, 

BART benchmark, and BART 

Alternative). As discussed in section 

V.B.2.e, the State’s use of different 

meteorological years may introduce 

some error as the visibility 

improvements could be driven by yearto-year variability in meteorological 

conditions, as opposed to the 

differences in emission reductions 

between the BART Alternative and 

BART Benchmark. For this reason, in 

addition to the information from the 

State, EPA has also calculated the 

visibility improvements for each 

modeling scenario using paired-in-time 

meteorological and emissions data.152

Using this method, whether the BART 

Alternative resulted in lower 98th 

percentile impacts depends on both the 

particular Class I area and 

meteorological year modeled. In some 

years and some Class I areas, 

particularly some of the most impacted 

Class I areas, the BART Benchmark 

shows better visibility improvement 

than the BART Alternative (for example, 

0.93 dv greater improvement for 

Canyonlands and 0.75 in 2002 dv 

greater improvement for Capitol Reef in 

2001).153 At other Class I areas, the 98th 

percentile metric indicates that the 

BART Alternative provides greater 

visibility improvement (for example, by 

0.90 dv at Arches in 2003 and 0.43 dv 

at Flat Tops in 2002).154 On the whole, 

when using this method, the BART 

Benchmark is slightly better on average 

across all years and nine Class I areas 

(0.14 dv difference).155 We propose to 

find, consistent with the State’s 

evaluation, that this metric favors the 

BART Benchmark. 

iv. Annual Average Impact (dv) 

As discussed previously in section 

IV.C.5, Utah’s modeling shows that the 

average annual dv impact at all Class I 

areas is better under the Utah BART 

Alternative at five of the nine Class I 

areas, and is better on average across all 

the Class I areas. The average impact 

was calculated by averaging all daily 

modeling results for each year and then 

calculating a three-year average from the 

annual average. Utah’s information 

shows that the BART Alternative is 

better than the BART Benchmark by 

0.009 dv on average across all nine Class 

I areas. While EPA has not considered 

this metric in the past,156 since the State 

includes it,157 we consider it here. 

Furthermore, the BART Guidelines state 

that, ‘‘in determining what, if any, 

emission controls should be required, 

the State will have the opportunity to 

consider the frequency, duration, and 

intensity of a source’s predicted effect 

on visibility.’’ 158 We note that the 

difference in the annual average metric 

of 0.009 dv only marginally supports the 

BART Alternative and that this metric 

shows less or equal visibility 

improvement at four of the nine Class I 

areas. Because the annual average 

metric averages over all days, it does not 

represent the benefits of the BART 

Alternative on the maximum impact 

days. In previous evaluations of BART 

alternatives we have relied on either the 

98th percentile metric or the average 

improvement for the worst 20% 

IMPROVE monitoring days to evaluate 

greater reasonable progress. Therefore, 

we propose to find that the information 

from the annual average metric does not 

support a conclusion that the BART 

Alternative achieves greater reasonable 

progress than the BART Benchmark. 

v. 90th Percentile Impact (dv) 

As discussed previously in section 

IV.C.5, Utah’s comparison of the 

modeled visibility impacts at the 90th 

percentile (the 110th highest day in a 

year) dv impact shows that the Utah 

BART Alternative is better at seven of 

the nine Class I areas and is slightly 

better averaged both across three years 

and across nine Class I areas (0.006 dv 

difference). We note that the use of the 

90th percentile impacts to evaluate 

alternatives has not been EPA’s practice 

for source-specific BART 

determinations; however, as discussed 

previously for the average dv impact 

metric, the BART Guidelines allow 

states to consider other visibility metrics 

in addition to the 98th percentile. Yet, 

because of the small difference between 

the two scenarios (0.006 dv), we 

propose to find that it is questionable 

whether the 90th percentile supports a 

conclusion that the BART Alternative 

achieves greater reasonable progress. 

vi. Timing for the Emissions Reductions 

As discussed previously in section 

IV.C.5, assuming the four BART units 

receive five years to come into 

compliance, Utah noted that reductions 

under the Utah BART Alternative will 

occur earlier than the BART Benchmark. 

The reductions under the Utah BART 

Alternative are required under the State 

SIP by August 2015, as noted in Table 

5, and would provide an early and ongoing visibility benefit as compared to 

BART. Also notable is that combustion 

control upgrades at the Hunter and 

Huntington facilities have been 

achieving significant NOX reductions 

since the time of their installation 

between 2006 and 2014, depending on 

the unit.159 Finally, if, as proposed in 

section VI.C, BART for the four units is 

LNB/SOFA plus SCR, BART likely 

would be fully implemented sometime 

between 2019 and 2021. 

Therefore, we recognize that the 

reductions from the BART Alternative 

would occur before the BART 

Benchmark. 

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160Utah Regional Haze State Implementation 

Plan, Technical Support Document, Ch. 1, p. 12 

(2015). 

161 Id. at p. 15. 

162 Id. at p. 12. 

163 Id. at p. 14. 

164 Id. at p. 13. 

165 Id. 

166 Id. at pp. 16–19. 

167Fountoukis, C. & Nenes, A., ISORROPIA II: A 

Computationally Efficient Aerosol Thermodynamic 

Equilibrium Model for K∂, Ca2

∂, Mg2∂, NH4∂, 

Na∂, SO4

2¥, NO3

¥, Cl¥, H2O Aerosols, 7 Atmos. 

Chem. Phys., 4639–4659 (2007). 

168Seinfeld, John H., Urban Air Pollution: State 

of the Science, 243 Science Magazine, no. 4892, 

745, 750 (1989). 

169 70 FR 39104, 39130 (July 6, 2005) (‘‘Other 

ways that visibility improvement may be assessed 

to inform the control decisions would be to 

examine distributions of the daily impacts, 

determine if the time of year is important (e.g., high 

impacts are occurring during tourist season), 

consideration of the cost-effectiveness of visibility 

improvements (i.e., the cost per change in 

deciview), using the measures of deciview 

improvement identified by the State, or simply 

compare the worst case days for the pre- and postcontrol runs. States may develop other methods as 

well.’’). 

170See, e.g., 78 FR 79344 (Dec. 30, 2012) 

(proposed rule, FIP for Tesoro Refining BART 

Alternative); 79 FR 33438, 33441 (June 11, 2014) 

(final rule, FIP for Tesoro Refining BART 

Alternative); 79 FR 56322, 56328 (Sept. 19, 2014) 

(proposed approval of Arizona Apache BART 

Alternative); 80 FR 19220 (Apr. 10, 2015) (final 

approval of Arizona Apache BART Alternative); 77 

FR 11827, 11837 (Feb. 28, 2012) (proposed approval 

of Maryland BART Alternative); 77 FR 39938, 

39940–1 (July 6, 2012) (final approval of Maryland 

BART Alternative). 

vii. IMPROVE Monitoring Data 

Utah’s SIP presents sulfate and nitrate 

monitoring data at the Canyonlands 

IMPROVE monitor that show that 

‘‘sulfates are the dominant visibility 

impairing pollutant’’ 160 and that sulfate 

levels have decreased,161 and references 

similar results at other Class I areas in 

the TSD.162 Utah also presents data on 

trends in emissions from EGUs showing 

substantial reductions in emissions of 

both SO2 and NOX.163 Based on these 

data, Utah indicates it ‘‘has confidence 

that the SO2 reductions will achieve 

meaningful visibility improvement’’, 

under the Utah BART Alternative,164

while ‘‘the visibility improvement 

during the winter months due to NOX

reductions is much more uncertain,’’ 165

Utah makes this point even though 

nitrate concentrations are highest in the 

winter, explaining that while there has 

been a reduction in NOX, the 

ammonium nitrate values do not show 

similar improvement in the winter 

months. Utah offers several possible 

explanations for the results, but does 

not provide any definitive 

conclusions.166

Utah also presents data on the 

seasonality of park visitation and 

monitoring data for nitrate and sulfates. 

These data show the highest measured 

nitrate concentrations occur in winter 

during the period of lowest park 

visitation, and that sulfates affect 

visibility throughout the year and are 

the dominant visibility impairing 

pollutant from anthropogenic sources 

during the high visitation period of 

March through November. Utah 

concludes that it has greater confidence 

that reductions in SO2 will be reflected 

in improved visibility for visitors to the 

Class I areas, while reductions in NOX

will have a more uncertain benefit for 

visitors to Class I areas. We invite 

comment on the information and 

conclusions provided by Utah as 

summarized earlier. 

We propose to concur with one of the 

State’s findings. We propose to find that 

visibility benefits associated with NOX

reductions are much more likely to 

occur in the winter months because this 

is when aerosol thermodynamics favors 

nitrate formation.167 By contrast, SO2

emissions reductions should provide 

visibility benefits in all seasons.168 We 

also propose to find that, as concluded 

by the GCVTC, and supported by the 

IMPROVE monitoring data presented by 

Utah, anthropogenic visibility 

impairment on the Colorado Plateau is 

dominated by sulfates. Therefore, we 

propose to concur with Utah’s statement 

that sulfate is the largest contributor to 

visibility impairment at the affected 

Class I areas. 

We propose to disagree with the 

State’s findings related to park 

visitation. While the BART Guidelines 

do mention visitation as something that 

can inform a control decision,169 EPA is 

proposing to place little weight on the 

State’s correlation of emissions 

reductions and park visitation because 

nothing in the CAA suggests that 

visitors during busy time periods are 

entitled to experience better visibility 

than visitors during off-peak periods. 

On the contrary, in the Regional Haze 

provisions of the CAA, Congress 

declared a national goal of remedying 

all manmade visibility impairment in all 

class I areas, which includes both 

heavily-visited national parks and 

seldom-visited wilderness areas. We 

invite comment on our evaluation and 

the information and conclusions 

provided by Utah as summarized 

previously. 

viii. Energy and Non-Air Quality 

Benefits 

EPA’s evaluation of the State’s 

information on energy and non-air 

quality benefits is located earlier in 

section V.B.2.e.viii. 

ix. Cost 

EPA’s evaluation of the Utah’s cost 

information is located in section 

V.B.2.e.ix. 

f. Evaluation of the Weight of Evidence 

In this section we evaluate Utah’s SIP 

under 40 CFR 51.308(e)(2), to determine 

whether the State met the final step of 

the better-than-BART analysis ‘‘based 

on the clear weight of evidence that the 

trading program or other alternative 

measure achieves greater reasonable 

progress than would be achieved 

through the installation and operation of 

BART at the covered sources.’’ 40 CFR 

51.308(e)(2)(i)(E). 

As discussed previously, we 

evaluated Utah’s demonstration and all 

available information and data 

presented by the State, as well as 

additional information and data EPA 

developed and presented in this notice. 

We propose to find that this information 

and data do not meet the requirements 

of 40 CFR 51.308(e)(2)(i)(E). 

Specifically, we propose that Utah’s 

demonstration does not show by the 

‘‘clear weight of evidence’’ that the 

BART alternative ‘‘measure achieves 

greater reasonable progress than would 

be achieved through the installation and 

operation of BART at the covered 

sources.’’ 40 CFR 51.308(e)(2)(i)(E). We 

have evaluated the relative strengths 

and weakness of the information and 

propose to find that the State’s analysis 

and conclusions do not clearly show 

that the BART Alternative results in 

greater reasonable progress than the 

BART Benchmark for the following 

reasons: (1) The key metric EPA has 

used in evaluating alternatives (98th 

percentile) on average across all the 

Class I areas favors the BART 

Benchmark by 0.14 dv and not the 

BART Alternative; (2) the majority of 

information and data that the State 

asserts favor the BART Alternative over 

BART show small differences; (3) the 

comparison of net emissions reductions 

across three pollutants, which the State 

relies on significantly is not appropriate 

because not all pollutants are reduced 

under the BART Alternative and each 

pollutant may have different effects on 

visibility; and (4) while some 

information may show the Alternative is 

better than BART, the information is not 

adequate to meet the ‘‘clear weight of 

evidence’’ test. 

First, consistent with the Agency’s 

practice, we have considered all 

information, but have given most weight 

to the visibility impacts based on air 

quality modeling.170 Here, the 98th 

percentile impacts from the State’s 

CALPUFF modeling show that the 

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171 40 CFR 51, appendix Y, section IV.D. 

172See id. section IV.E. 

173EPA’s CCM Sixth Edition, January 2002, EPA 

452/B–02–001. 

174Chapter 1, Selective Noncatalytic Reduction, 

—6/5/2015—Draft for Public Comment (‘‘the 2015 

SNCR CCM’’); Chapter 2 Selective Catalytic 

Reduction, —6/5/2015—Draft for Public Comment 

(‘‘the 2015 SCR CCM’’). The draft CCM SNCR and 

SCR revisions were made available for public 

comment in a Notice of Data Availability (NODA) 

on June 12, 2015, 80 FR 33515, and on July 17, 

2015, 80 FR 42491, the public comment period was 

extended to September 10, 2015. In this co-proposal 

for Utah’s regional haze SIP, we are not taking 

comment on the revisions to the CCM. We are only 

taking comment on the application of those 

revisions of the CCM to the particular facts and 

circumstances for the two subject-to-BART sources, 

Hunter and Huntington, at issue in this action. 

BART Alternative is not better than the 

BART Benchmark because the BART 

Benchmark would provide a 0.14 dv 

greater average improvement than the 

BART Alternative. In addition, Table 12 

lists a comparison of 2001–2003 threeyear average 98th percentile visibility 

improvement for each of the nine Class 

I areas; and the results for seven of the 

Class I areas favor BART over the 

Alternative (Black Canyon of the 

Gunnison (0.06 dv), Bryce Canyon (0.04 

dv), Canyonlands (0.78 dv), Capitol Reef 

(0.59 dv), Grand Canyon (0.06 dv), Mesa 

Verde (0.12 dv), and Zion (0.02 dv)). 

Second, several metrics that the State 

suggests favor the BART Alternative 

over BART show only small 

improvements as compared to BART. 

We propose to find that the slight 

comparative benefits in the annual 

average impacts are not compelling 

evidence that the BART Alternative will 

provide for greater reasonable progress 

than BART. Additionally, we propose to 

find that it is questionable whether the 

90th percentile supports a conclusion 

that the BART Alternative will provide 

for greater reasonable progress than 

BART. 

Third, regarding the energy and nonair quality impacts, as well as cost, for 

the reasons presented previously, we 

propose to find that because these 

metrics do not have a direct bearing on 

whether the Utah BART Alternative 

achieves greater reasonable progress, it 

is not material to our action whether we 

agree or disagree with Utah’s assessment 

that they reduce energy and non-air 

quality impact. 

As explained previously in this 

section, in the aggregate the SO2 and 

PM10 emissions are lower for the BART 

Alternative. However, the NOX

emissions are greater under the BART 

Alternative. Additionally, while Utah’s 

results show that some of the metrics 

support the Alternative (e.g., there are 

fewer days with impacts over 0.5 dv for 

the Alternative indicating greater 

improvement in visibility under the 

BART Alternative; emission reductions 

would occur earlier under the 

Alternative; the Alternative will result 

in 8,005 tpy lower SO2 emissions and 

573 tpy lower PM10 emissions compared 

to the BART Benchmark; sulfate is the 

largest contributor to visibility 

impairment at the affected Class I areas), 

we propose to find that these metrics are 

not enough by themselves to meet the 

‘‘clear weight of evidence’’ test. 

Thus, we propose to find that the 

BART Alternative does not meet the 

requirements in the RHR because it does 

not show the BART Alternative would 

achieve greater reasonable progress than 

the BART Benchmark, and therefore, we 

are proposing to disapprove the 

resultant BART Alternative SIP. 

g. Evaluation That Emission Reductions 

Take Place During Period of First LongTerm Strategy 

EPA’s evaluation of Utah’s 

information regarding the timing of 

implementation of controls is located in 

section V.B.2.g. 

h. Demonstration That Emission 

Reductions From Alternative Program 

Will Be Surplus 

EPA’s evaluation of Utah’s 

information regarding whether the 

emission reductions are surplus is 

located in section V.B.2.h. 

C. Monitoring, Recordkeeping and 

Reporting for Utah’s BART Alternative 

As discussed previously in section 

IV.B.3, Utah’s June 2015 RH SIP 

includes enforceable measures and 

monitoring, recordkeeping and 

reporting requirements for the Utah 

BART Alternative and the State’s PM10

BART determinations. Because in this 

co-proposal we are proposing to 

disapprove Utah’s BART Alternative, 

we are also proposing to disapprove (in 

other words, to not make federally 

enforceable as part of the SIP) the 

monitoring, recordkeeping and 

reporting requirements located in SIP 

Sections IX.H.22 associated with the 

BART Alternative. This includes SIP 

Section IX.H.22, subsections a.ii, a.iii, 

b.ii, and c.i. 

Concurrently, as described earlier in 

section V.C, we are proposing to 

approve the remainder of the 

monitoring, recordkeeping and 

reporting requirements associated with 

Utah’s PM10 BART determinations. This 

includes SIP Section IX.H.21 in its 

entirety and Section IX.H.22, 

subsections a.i and b.i. 

D. Proposed Federal Implementation 

Plan 

The following explanation details the 

support for EPA’s FIP proposed in 

conjunction with the proposed partial 

approval and partial disapproval of 

Utah’s SIP. This FIP constitutes EPA’s 

proposed determination of NOX BART 

for Utah’s four subject-to-BART sources. 

1. BART Evaluations 

In determining BART, the state, or 

EPA if promulgating a FIP, must 

consider the five statutory factors in 

section 169A(g)(2) 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). Our evaluation 

of BART for Hunter and Huntington 

follows the Guidelines for BART 

Determinations Under the Regional 

Haze Rule. 

Following the identification of 

subject-to-BART sources as described in 

section IV.A.3, the next step of a BART 

evaluation is to perform the BART 

analysis. The BART Guidelines describe 

the BART analysis as consisting of the 

following five steps: 171

• 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. 

The results of this five step analysis 

are then used to select BART, taking 

into consideration the five factors listed 

earlier.172

Immediately following this, we 

provide background information that is 

common to our cost of compliance 

analysis (under Step 4) and visibility 

impacts analysis (step 5) for all BART 

sources. This is followed by the five 

step analysis and proposed selection of 

BART specific to each BART source. 

a. Costs of Compliance 

In accordance with the BART 

Guidelines, we have estimated the costs 

of compliance consistent with the EPA 

Air Pollution Control Cost Manual 

(CCM).173 In addition, we have utilized 

portions of the draft 2015 revisions to 

the CCM chapters for the postcombustion NOX control technologies, 

selective non-catalytic reduction (SNCR) 

and selective catalytic reduction 

(SCR).174 In addition, we rely on the 

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175Cost of NOX BART Controls on Utah EGUs, 

from Andover Technology Partners, to EC/R, Inc., 

October 22, 2015 (ATP report). Andover 

Technology Partners is a subcontractor to EC/R 

Incorporated. 

176Air Quality Modeling Protocol: Utah Regional 

Haze Federal Implementation Plan, EPA Region 8, 

November 2015. 

177U.S. Energy Information Administration, 

Electric Generating Capacity for 2011 taken from 

Form EIA–860. See spread sheet titled ‘‘EIA existing 

generating units 2011.xls’’ in the docket. 

178 40 CFR part 51, appendix Y, IV.E.5, Table. 1. 

179See 40 CFR 51.301 (definition of BART); 40 

CFR 51.308(e). 

180PacifiCorp BART Analysis for Hunter Units 1 

(July 2, 2012); PacifiCorp BART Analysis for Hunter 

Unit 2 (June 7, 2012); Utah’s Regional Haze BART 

Submittal, Chapter 2 of the Technical Support 

Document (2015); PacifiCorp’s BART Analysis 

Update for Hunter Units 1 and 2 and Huntington 

Units 1 and 2 (Aug. 5, 2014). 

cost of compliance estimates supplied to 

EPA by Andover Technology Partners 

(ATP).175 These estimates in turn rely 

on the cost estimates that PacifiCorp 

submitted to Utah in 2012 and 2014, but 

with those cost estimates adjusted in a 

number of cases for reasons described in 

the ATP report. All costs are presented 

in 2014 dollars. Refer to the ATP report 

and associated spread sheets for details 

on how the costs of compliance are 

calculated. 

b. Visibility Impact Modeling 

The BART Guidelines provide that 

states may use the CALPUFF modeling 

system or another appropriate model to 

determine the visibility improvement 

expected at affected Class I areas from 

potential BART control technologies. 

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. In 

consultation with EPA, Utah developed 

a CALPUFF modeling protocol titled 

‘‘Air Quality Modeling Protocol: Utah 

Regional Haze State Implementation 

Plan’’, February 13, 2015, to support its 

BART Alternative analysis (see Chapter 

6 of the State’s TSD). The Utah protocol 

follows recommendations for long-range 

transport described in appendix W to 40 

CFR part 51, Guideline on Air Quality 

Models, and in the federal 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). Utah’s protocol also follows 

Federal Land Managers’ Air Quality 

Related Values Workgroup—Phase I 

Report (revised 2010). In section VI.B.e, 

we evaluate the State’s modeling 

approach in consideration of the 

purpose for which it is intended (i.e., 

analyzing the BART Alternative). 

However, because Utah’s modeling is 

not meant to support analysis of control 

options for individual BART sources 

under a five factor analysis, EPA 

developed separate CALPUFF modeling 

for this purpose. While the Utah 

modeling assesses the combined 

impacts of all of the BART and nonBART sources included in the BART 

Alternative—Carbon, Hunter, and 

Huntington—our modeling assesses the 

impacts of the individual BART sources. 

In addition, our modeling assesses the 

visibility impacts of all of the NOX

BART control technologies found to be 

technologically feasible in Step 2: LNB 

and OFA, LNB and OFA with SNCR, 

and LNB and OFA with SCR. Beyond 

assessing impacts from individual 

BART sources and evaluating all 

technologically feasible control options, 

our modeling methodology is otherwise 

very similar to that employed by Utah. 

Our modeling protocol, and visibility 

impact results, can be found in the 

docket.176 Also, the visibility impacts 

for each BART source are provided later 

in the respective five factor analyses. 

EPA notes that, in considering the 

visibility improvements reflected in our 

revised modeling, EPA interprets the 

BART Guidelines to require 

consideration of the visibility 

improvement from BART applied to the 

entire BART-eligible source. The BART 

Guidelines explain that, ‘‘[i]f the 

emissions from the list of emissions 

units at a stationary source exceed a 

potential to emit of 250 tons per year for 

any visibility-impairing pollutant, then 

that collection of emissions units is a 

BART-eligible source.’’ In other words, 

the BART-eligible source (the list of 

BART emissions units at a source) is the 

collection of units for which one must 

make a BART determination. The BART 

Guidelines state ‘‘you must conduct a 

visibility improvement determination 

for the source(s) as part of the BART 

determination.’’ This requires 

consideration of the visibility 

improvement from BART applied to the 

subject-to-BART source as a whole. 

We note, however, that while our 

regulations require states and EPA to 

assess visibility improvement on a 

source-wide basis, they provide 

flexibility to also consider unit-specific 

visibility improvement in order to more 

fully inform the reasonableness of a 

BART determination, but that does not 

replace the consideration of visibility 

benefit from the source (facility) as a 

whole. In making the BART 

determinations in this final action we 

have considered visibility 

improvements at the source, and then 

also at the units that comprise the 

source. 

2. Hunter Power Plant 

As described previously in section 

IV.A, Hunter Units 1 and 2 were 

determined to be subject to BART, while 

Unit 3 is not subject to BART. Hunter 

Units 1 and 2 have a nameplate 

generating capacity of 488.3 MW 

each.177 The boilers are tangentially 

fired pulverized coal boilers, burning 

bituminous coal from the Deer Creek 

Mine in Utah. 

Our evaluation of BART for Hunter 

Units 1 and 2 follows the BART 

Guidelines. For Hunter Units 1 and 2, 

the BART Guidelines are mandatory 

because the combined capacity for all 

three units at the Hunter facility is 

greater than 750 MW. See 40 CFR 

51.302(e)(1)(ii)(B) (‘‘The determination 

of BART for fossil-fuel fired power 

plants having a total generating capacity 

greater than 750 megawatts must be 

made pursuant to the guidelines in 

appendix Y of this part’’). Under the 

Guidelines, cost estimates for control 

technologies should be based on the 

CCM, where possible. 

The BART Guidelines establish 

presumptive NOX limits for coal-fired 

EGUs greater than 200 MW located at 

greater than 750 MW power plants that 

are operating without post-combustion 

controls. For the tangential-fired boilers 

burning bituminous coal at Hunter, that 

presumptive limit is 0.28 lb/MMBtu.178

The BART Guidelines provide that the 

five factor analysis may result in a limit 

that is different than the presumptive 

limit, and the presumptive limits do not 

obviate the need to determine BART on 

a case-by-case basis considering the five 

factors.179

PacifiCorp provided BART analyses 

for Hunter Unit 1 to Utah in 2012 and 

2014 which we utilize in our proposed 

BART evaluation here.180 Although we 

are using some information provided by 

Utah and PacifiCorp, we are 

independently evaluating all five 

statutory BART factors, as is appropriate 

for this co-proposed FIP. 

a. Hunter Unit 1 

The Hunter Unit 1 boiler is of 

tangential-fired design with newer 

generation low-NOX burners and 

separated overfire air which were 

installed in 2014. Unit 1 currently 

achieves an annual emission rate of 

approximately 0.21 lb/MMBtu with 

these combustion controls. Under 

Utah’s submitted regional haze SIP, Unit 

1 is subject to a state-law NOX emission 

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181 2012 PacifiCorp BART analysis for Hunter 

Unit 1, page 2.a–106. 

182BART Guidelines, IV.D.1. 

183 2012 PacifiCorp BART analysis for Hunter 

Unit 1, pages 2.a–106 through 2.a–123. 

184White Paper, SNCR for Controlling NOX

Emissions, Institute of Clean Air Companies, pp. 4 

and 9, February 2008. 

185 2015 SNCR CCM, Figure 1.1c: SNCR NOX

Reduction Efficiency Versus Baseline NOX Levels 

for Coal-fired Utility Boilers. 

186Srivastava, R., Hall, R., Khan, S., Lani, B., & 

Culligan, K., Nitrogen Oxides Emission Control 

Options for Coal-Fired Utility Boilers, 55 J. Air & 

Waste Mgmt. Assoc. 1367, 1367–88 (2005). 

187See 79 FR 5032, 5133 (Jan. 30, 2014) 

(discussing reasons for rejecting use of AFUDC). 

limit of 0.26 lb/MMBtu on a 30-day 

rolling average. Prior to the installation 

of LNB and SOFA the unit operated 

with an actual annual emission rate of 

about 0.40 lb/MMBtu. 

Step 1: Identify All Available NOX

Control Technologies 

In its 2012 BART analysis for Hunter 

Unit 1, PacifiCorp identified several 

NOX control technologies, both for 

combustion controls and postcombustion controls.181 The 

combustion controls identified by 

PacifiCorp include: low-NOX burners 

and separated overfire air (LNB and 

SOFA; already installed), rotating 

overfire air, neural network 

optimization system, flue gas 

recirculation, gas reburn, fuel lean gas 

reburn, coal switching, water injection, 

and others. Post-combustion control 

options identified by PacifiCorp 

include: SNCR, rich reagent injection 

(RRI), SCR, and others. 

We note that the combustion controls, 

LNB and SOFA, have already been 

installed on Hunter Unit 1, and so we 

consider them here as ‘‘any existing 

controls’’ under the third statutory 

BART factor. In addition, the BART 

Guidelines recognize that 

‘‘[c]ombinations of inherently loweremitting processes and add-on controls’’ 

are a category of retrofit controls which 

can be considered.182 Accordingly, the 

inherently lower-emitting combustion 

controls, LNB and SOFA, are evaluated 

in combination with the add-on 

controls, SNCR and SCR. 

We have reviewed PacifiCorp’s review 

of NOX control technologies and find it 

to be comprehensive. We propose to 

adopt it to satisfy Step 1 and we refer 

the reader to the 2012 PacifiCorp BART 

analysis for details on the available NOX

control technologies. 

Step 2: Eliminate Technically Infeasible 

Options 

In its 2012 BART analysis,183

PacifiCorp eliminated available NOX

control technologies that PacifiCorp 

evaluated as technologically infeasible 

for Hunter Unit 1. The remaining 

technologically feasible control 

technologies are the combustion 

controls, LNB and SOFA, and the postcombustion controls, SNCR and SCR. 

We agree with PacifiCorp’s evaluation 

of technologically available controls for 

Hunter Unit 1 and propose to adopt it 

for Step 2. 

Step 3: Evaluate Control Effectiveness of 

Remaining Control Technologies 

As noted previously, Hunter Unit 1 is 

currently achieving an actual annual 

emission rate of approximately 0.21 lb/ 

MMBtu with LNB and SOFA. This 

represents a 48.4 percent reduction from 

the baseline emission rate of 0.40 lb/

MMBtu. 

The post-combustion control 

technologies, SNCR and SCR, have been 

evaluated in combination with 

combustion controls. That is, the inlet 

concentration to the post-combustion 

controls is assumed to be 0.21 lb/

MMBtu (annual). This allows the 

equipment and operating and 

maintenance costs of the postcombustion controls to be minimized 

based on the lower inlet NOX

concentration. 

Typically, SNCR reduces NOX an 

additional 20 to 30 percent above 

combustion controls without excessive 

NH3 slip.184 For this analysis, the 

control efficiency of SNCR has been 

calculated based on the formula in the 

2015 draft CCM SNCR chapter,185 which 

for Hunter Unit 1 yields an additional 

reduction of 21.4 percent after 

combustion controls. When combined 

with LNB and SOFA, SNCR is 

anticipated to achieve an annual 

emission rate of 0.16 lb/MMBtu, 

corresponding to an overall control 

efficiency of 59.4 percent. 

SCR can achieve performance 

emission rates as low as 0.04 to 0.07 lb/ 

MMBtu on an annual basis.186 For this 

analysis, consistent with our actions 

elsewhere, as well with PacifiCorp’s 

analysis, we use an annual emission rate 

of 0.05 lb/MMBtu for SCR, which when 

combined with LNB and SOFA achieves 

an overall control efficiency of 87.5 

percent. 

A summary of emissions projections 

for the control options evaluated is 

provided in Table 13. 

TABLE 13—SUMMARY OF NOX BART ANALYSIS CONTROL TECHNOLOGIES FOR HUNTER UNIT 1 

Control option 

Control 

effectiveness 

(%) 

Annual 

emission rate 

(lb/MMBtu) 

Emissions 

reduction 

(tpy) 

Remaining 

emissions 

(tpy) 

LNB/SOFA +SCR ............................................................................ 87.5 0.05 5,500 784 

LNB/SOFA +SNCR .......................................................................... 59.4 0.16 3,735 2,549 

LNB/SOFA ....................................................................................... 48.4 0.21 3,042 3,242 

Baseline1 .......................................................................................... ............................ 0.40 ............................ 6,284 

1Baseline emissions were determined by averaging the annual emissions from 2001 to 2003 as reported to EPA Air Markets Program Data, 

available at http://ampd.epa.gov/ampd/. The annual emissions data is presented in Chapter 4.a of Utah’s June 2015 submittal. 

Step 4: Evaluate Impacts and Document 

Results 

Under Step 4, the Guidelines list 

impact analyses in four parts: costs of 

compliance, energy impacts, non-air 

quality environmental impacts, and 

remaining useful life. For convenience, 

we combine energy and non-air quality 

environmental impacts later on. 

Part 1—Costs of Compliance 

We obtained capital costs for LNB and 

SOFA from the 2014 PacifiCorp BART 

analysis. PacifiCorp did not report any 

operating and maintenance costs for 

LNB and SOFA. Similarly, we obtained 

capital cost estimates for LNB and 

SOFA with SNCR from the 2014 

PacifiCorp BART analysis. However, for 

operating and maintenance costs we 

propose to rely on the draft 2015 draft 

SNCR chapter of the CCM. Refer to the 

ATP report for details. Capital costs for 

LNB and SOFA with SCR were also 

obtained from the 2014 PacifiCorp 

BART analysis. However, PacifiCorp’s 

capital costs were adjusted to account 

for items that were double-counted or 

should not be allowed under the CCM, 

such as an allowance for funds used 

during construction (AFUDC).187 In 

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188EPA Air Pollution Control Cost Manual p. 1– 

21 (6th ed. 2002), available at http://www3.epa.gov/ 

ttncatc1/dir1/c_allchs.pdf. 

addition, the capital costs were adjusted 

to account for a significant 

overestimation of the catalyst volume 

and related costs. These adjustments are 

documented in the ATP report and 

associated spread sheet. A discussion of 

operating and maintenance costs of SCR 

is also included in the ATP report. For 

the reasons given in the report, we 

propose to adopt the cost estimates 

contained in it. 

A summary of our proposed cost 

estimates for all control options is 

presented in Table 14. 

TABLE 14—SUMMARY OF NOX BART COSTS ON HUNTER UNIT 1 

Control option Total capital 

investment 

Indirect annual 

costs 

Direct annual 

costs Total annual cost 

Emissions 

reductions 

(tpy) 

Average cost 

effectiveness 

($/ton) 

LNB/SOFA ....................... $11.6M $1.2M $0M $1.2M 3,042 $382 

LNB/SOFA/SNCR ............ 19.0M 1.9M 1.9M 3.8M 3,735 1,016 

LNB/SOFA/SCR ............... 110.3M 10.5M 2.5M 13.1M 5,500 2,380 

Parts 2 and 3—Energy and Non-Air 

Quality Environmental Impacts of 

Compliance 

SNCR slightly reduces the thermal 

efficiency of a boiler as the reduction 

reaction uses thermal energy from the 

boiler, decreasing the energy available 

for power generation.188 Using the CCM, 

we have calculated the electrical power 

consumption of SNCR to be 326,000 

kW-hr per year for Hunter Unit 1. 

For SCR, the thermal efficiency is 

much more reduced because the new 

ductwork and the reactor’s catalyst 

layers decrease the flue gas pressure. As 

a result, additional fan power is 

necessary to maintain the flue gas flow 

rate through the ductwork and reactor. 

Using the CCM, we have calculated the 

electrical power consumption of SCR to 

be approximately 18,541,000 kW-hr per 

year for Hunter Unit 1. 

Both SCR and SNCR also require 

some minimal electricity to service 

pretreatment and injection equipment, 

pumps, compressors, and control 

systems. The energy requirements 

described earlier are not significant 

enough to warrant elimination of either 

SNCR or SCR as BART. In addition, the 

cost of the additional energy 

requirements has been included in our 

cost effectiveness calculations. 

SNCR and SCR will slightly increase 

the quantity of ash that will need to be 

disposed. In addition, transportation 

and storage of chemical reagents may 

result in spills or releases. However, 

these non-air quality environmental 

impacts do not warrant elimination of 

either SNCR or SCR as BART. 

There are no additional energy 

requirements associated with the new 

LNB and SOFA, and no significant nonair quality environmental impacts. 

In summary, we propose to determine 

that we have adequately considered 

these impacts by including cost of 

additional energy in cost effectiveness 

and assessing non-air quality 

environmental impacts as insufficient to 

eliminate or weigh against any of the 

BART options. 

Part 4—Remaining Useful Life 

PacifiCorp assumes a remaining 

useful life of at least 20 years for Hunter 

Unit 1 in its BART analysis, and has not 

indicated any intention to retire, or 

curtail generation from, Hunter Unit 1. 

Therefore, this factor does not preclude 

any of the control options considered. In 

addition, this factor is consistent with 

our BART calculation of cost 

effectiveness because annualized costs 

have been calculated over a 20 year 

period for each of the control options 

considered. We propose that this gives 

adequate consideration to this factor. 

Step 5: Evaluate Visibility Impacts 

Table 15 presents the highest of the 

98th percentile visibility improvements 

at the affected Class I areas for the three 

meteorological years modeled, 2001 

through 2003. Tables 16 and 17 present 

the number of days (summed across 

three years) with impacts greater than 

the contribution and causation 

thresholds—0.5 dv and 1.0 dv, 

respectively. 

TABLE 15—HUNTER UNIT 1—VISIBILITY IMPROVEMENTS

Class I area LNB with SOFA 

(Ddv) 

LNB with SOFA 

and SNCR 

(Ddv) 

LNB with SOFA 

and SCR 

(Ddv) 

Arches NP .................................................................................................................. 0.737 0.906 1.342 

Black Canyon of the Gunnison NP ........................................................................... 0.198 0.241 0.345 

Bryce Canyon NP ...................................................................................................... 0.306 0.372 0.534 

Canyonlands NP ........................................................................................................ 0.846 1.041 1.545 

Capitol Reef NP ......................................................................................................... 0.639 0.750 1.113 

Flat Tops WA ............................................................................................................. 0.231 0.280 0.404 

Grand Canyon NP ..................................................................................................... 0.349 0.426 0.618 

Mesa Verde NP ......................................................................................................... 0.235 0.286 0.426 

Zion NP ...................................................................................................................... 0.184 0.224 0.323 

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189See 79 FR 5032, 5105 (Jan. 30, 2014). 

TABLE 16—HUNTER UNIT 1—DAYS GREATER THAN 0.5 DECIVIEW

[Three year total] 

Class I area Baseline 

(days) 

LNB with SOFA 

(days) 

LNB with SOFA 

and SNCR 

(days) 

LNB with SOFA 

and SCR 

(days) 

Arches NP ................................................................................ 293 260 259 235 

Black Canyon of the Gunnison NP ......................................... 68 55 53 41 

Bryce Canyon NP .................................................................... 42 37 36 28 

Canyonlands NP ...................................................................... 359 330 322 311 

Capitol Reef NP ....................................................................... 175 160 156 145 

Flat Tops WA ........................................................................... 77 63 59 50 

Grand Canyon NP ................................................................... 49 43 42 37 

Mesa Verde NP ....................................................................... 82 66 63 55 

Zion NP .................................................................................... 29 23 23 22 

TABLE 17—HUNTER UNIT 1—DAYS GREATER THAN 1.0 DECIVIEW

[Three year total] 

Class I area Baseline 

(days) 

LNB with SOFA 

(days) 

LNB with SOFA 

and SNCR 

(days) 

LNB with SOFA 

and SCR 

(days) 

Arches NP ................................................................................ 170 141 139 122 

Black Canyon of the Gunnison NP ......................................... 22 13 12 9 

Bryce Canyon NP .................................................................... 22 19 18 16 

Canyonlands NP ...................................................................... 240 218 202 188 

Capitol Reef NP ....................................................................... 118 110 109 94 

Flat Tops WA ........................................................................... 31 20 18 10 

Grand Canyon NP ................................................................... 32 25 23 18 

Mesa Verde NP ....................................................................... 32 20 19 13 

Zion NP .................................................................................... 14 9 8 7 

Select BART. A summary of our impacts analysis 

for Hunter Unit 1 is presented in Table 

18. 

TABLE 18—SUMMARY OF HUNTER UNIT 1 IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/

MMBtu) 

Emission 

reduction 

(tpy) 

Total 

annual 

costs 

(million$) 

Average cost 

effectiveness 

($/ton) 

Incremental cost 

effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days 

> 0.5 dv 

Days 

> 1.0 dv 

LNB with SOFA .......... 0.21 3,042 $1.2M $382 ..................................... 0.846 330 218 

LNB with SOFA and 

SNCR.

0.16 3,735 3.8M 1,016 $3,796 ......................... 1.041 322 202 

LNB with SOFA and 

SCR.

0.05 5,500 13.1M 2,380 $5,268 (compared to 

LNB with SOFA and 

SNCR).

$4,853 (compared to 

LNB with SOFA). 

1.545 311 188 

* At the most impacted Class I area, Canyonlands National Park. 

In determining what to co-propose as 

BART, we have taken into consideration 

all five of the statutory factors required 

by the CAA: The costs of compliance, 

the energy and non-air quality 

environmental impacts of compliance, 

any existing pollution control 

technology in use at the source, the 

remaining useful life of the source, and 

the degree of improvement in visibility 

which may reasonably be anticipated to 

result from the use of such technology. 

Later we provide a justification for our 

selection of BART, including an 

explanation of how each of the CAA 

factors was used in that selection. 

As described in step 1 before, we have 

considered the existing pollution 

control technology in use at the source. 

We note that Hunter Unit 1 was 

equipped with LNB and SOFA in the 

spring of 2014 in order to meet state-law 

requirements in the 2011 Utah RH SIP 

submittal, which we did not approve. In 

this co-proposal we have to evaluate 

control technologies and baseline 

emissions from the correct starting 

point, that is, prior to the installation of 

the combustion controls pursuant to 

state-law NOX limitations.189 As a 

result, we used the period 2001–2003 as 

the appropriate period for baseline 

emissions, in order to provide a realistic 

depiction of annual emissions for 

Hunter Unit 1 prior to installation of 

combustion controls. 

We have considered the energy and 

non-air quality environmental impacts 

of compliance and propose to find that 

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190Nat’l Parks Conserv. Ass’n v. U.S. EPA, 788 

F.3d 1134, 1148–49 (9th Cir. 2014). 

191Even in that initial scenario, at least cost of 

compliance, as expressed in cost-effectiveness in 

dollars per ton, can be compared with what has 

been found reasonable for best available control 

technology (BACT) and reasonably available control 

technology (RACT), and visibility improvement can 

be compared with the 0.5 dv subject-to-BART 

threshold that determines whether a BART-eligible 

source causes or contributes to visibility 

impairment in Class I areas. The EPA notes that this 

alternate methodology would also support our 

proposed BART determinations in this action. 

192 79 FR 5032, 5047 (Jan. 30, 2014). 

193 79 FR 5032, 5049. 

194 77 FR 18069 (Mar. 26, 2012) (proposal); 77 FR 

76871 (Dec. 31, 2012) (final). 

195Colorado Department of Health and 

Environment, Air Pollution Control Division, Best 

Available Retrofit Technology (BART) Analysis of 

Control Options For Public Service Company— 

Hayden Station, p. 5, available at https://www.

colorado.gov/pacific/sites/default/files/AP_PO_

Hayden-Power-Plant_0.pdf. 

196 77 FR 42834 (July 20, 2012) (proposal); 77 FR 

72512, 72514–15 (Dec. 5, 2012) (final). 197We use the source-wide number here to 

compare with the Cholla determination; in addition 

as explained above we must consider source-wide 

visibility improvements. 

they do not appreciably favor one 

control option over another, or preclude 

a particular control option from 

selection. And finally, we have 

considered the remaining useful life of 

the source and find that it is sufficiently 

long (greater than 20 years) so as not to 

favor or preclude any of the control 

options. As a result, the remaining 

factors—the costs of compliance and 

visibility improvement—are the primary 

factors that lead us to our proposed 

BART selection for Hunter Unit 1. 

In order to select BART we propose to 

consider the costs of compliance and 

visibility impacts by generally 

comparing them with BART 

determinations that have been made 

elsewhere. In the context of reasonable 

progress determinations, a comparison 

with another reasonable progress 

determination has been upheld by the 

Ninth Circuit Court of Appeals as a 

rational explanation for that 

determination.190 If this were the first 

BART determination under the RHR and 

BART Guidelines, which it is not, it 

would obviously be difficult to employ 

this precise methodology.191 At this 

point, however, the EPA thinks there are 

sufficient examples of reasonable 

determinations to make this 

methodology feasible. 

Specifically, we propose to compare 

the average cost-effectiveness, 

incremental cost-effectiveness, visibility 

improvement, and incremental visibility 

improvement for LNB and SOFA with 

SCR with BART determinations where 

the EPA and States have based their 

determination on the same metrics. The 

most comparable determination appears 

to be in EPA’s final action for 

Wyoming’s regional haze SIP, in which 

EPA promulgated a FIP for three units 

at Laramie River Station and determined 

NOX BART to be LNB and SOFA with 

SCR for the three units.192 On a per-unit 

basis, the visibility improvement at the 

most impacted Class I area from this 

control option was 0.52 to 0.57 dv, and 

across all three units the sum of the 

improvement was 1.62 dv. Thus, the 

application of this control option to all 

three units of Laramie River Station was 

estimated to have a visibility benefit 

about the same as the application of this 

control option to Hunter Unit 1. The 

average cost-effectiveness ranged from 

$4,375/ton to $4,461/ton, considerably 

higher than the corresponding value for 

Hunter Unit 1, while the incremental 

cost-effectiveness ranged from $5,449 to 

$5,871/ton which is very close to the 

corresponding value for Hunter Unit 1. 

Finally, the incremental visibility 

improvement as compared to LNB and 

SOFA with SNCR was significant, as it 

is for Hunter Unit 1. On the other hand, 

at Dave Johnston Units 3 and 4 (for 

example), where EPA rejected LNB and 

SOFA with SCR, the incremental costeffectiveness value of LNB and SOFA 

with SCR was much higher and 

incremental visibility benefit lower than 

at Laramie River Station and higher than 

the same metrics at Hunter Unit 1.193

There are other BART determinations 

in which SCR has been selected as 

BART (either alone or in conjunction 

with LNB and SOFA) based on similar 

metrics, although those determinations 

may not have explicitly discussed 

incremental cost-effectiveness and 

incremental visibility benefits on a perunit basis. First, the State of Colorado 

selected, and the EPA approved, SCR as 

NOX BART for Public Service 

Company’s Hayden Station, Units 1 and 

2.194 Hayden Units 1 and 2 were 

equipped with first generation LNB and 

over-fire air (OFA) installed in 1999.195

In its BART determination, Colorado 

considered these existing controls as 

given and analyzed as feasible controls 

upgraded LNB, SNCR, and SCR. Based 

on an average cost-effectiveness of 

$3,385/ton and $4,064/ton, incremental 

cost-effectiveness (as compared with 

LNB and OFA with SNCR) of $5,326/ton 

and $7,331/ton, and visibility 

improvement of 1.12 dv and 0.85 dv at 

the most impacted Class I area, 

respectively, Colorado selected SCR as 

BART for Units 1 and 2. In this case, 

due to the existing controls at Hayden 

Station, the cost-effectiveness values for 

SCR for Hayden Units 1 and 2 should 

be compared to the incremental costeffectiveness values (as compared with 

LNB and SOFA, and with LNB and 

SOFA with SNCR) for SCR for Hunter 

Unit 1, and similarly for incremental 

visibility benefits. We think they are 

comparable, particularly for Hayden 

Unit 2, and considering that Hunter 

Unit 1 significantly impacts several 

Class I areas, while Colorado selected 

SCR for Hayden based solely on the 

visibility improvement at the most 

impacted Class I area, Mt. Zirkel 

Wilderness. 

Another comparable determination 

can be found in EPA’s FIP for Arizona 

Public Service’s Cholla Power Plant, 

Units 2, 3, and 4, in which EPA 

determined that NOX BART was SCR.196

Similarly to Colorado’s determination 

for Hayden, EPA considered the existing 

controls, LNB and OFA, at the three 

units and estimated average costeffectiveness values for SCR of $3,114/ 

ton, $3,472/ton, and $3,395/ton, and 

incremental cost-effectiveness values (as 

compared to LNB and OFA with SNCR) 

of $3,257/ton, $3,811/ton, and $3,661/

ton, respectively, for Units 2, 3, and 4. 

EPA’s modeling showed a source-wide 

visibility improvement for SCR of 1.34 

dv at the most impacted Class I area. 

Based on these metrics, EPA determined 

NOX BART to be SCR for the three units. 

In this case, as with Hayden, the average 

cost-effectiveness of SCR at Cholla 

should be compared with the 

incremental cost-effectiveness of SCR 

(as compared with just LNB and SOFA) 

at Hunter Unit 1. The cost-effectiveness 

values for Hunter Unit 1 are somewhat 

higher than at Cholla, but on the other 

hand the source-wide visibility 

improvement at Hunter Units 1 and 2 

(as obtained by summing the per-unit 

improvements from Units 1 and 2) 197

from LNB and SOFA with SCR is 2.759 

dv at the most impacted Class I area, 

with incremental visibility 

improvements of 1.29 dv and 0.932 dv 

over LNB and SOFA and LNB and 

SOFA with SNCR, respectively. These 

visibility improvements are very much 

in line with those at Cholla, and given 

that the incremental cost-effectiveness 

of SCR at Hunter Unit 1 is still 

reasonable, the comparison with Cholla 

also supports selection of SCR for 

Hunter Unit 1. We invite comment on 

other potentially relevant BART 

determinations and our methodology 

generally. 

Based on these comparisons to 

Laramie River Station, Hayden Station, 

Dave Johnston Units 3 and 4, and Cholla 

Power Plant, we think that selection of 

LNB and SOFA with SCR as BART for 

Hunter Unit 1 would be fully consistent 

with these prior actions. For Hunter 

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2038 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

198Emission limits such as BART are required to 

be met on a continuous basis. See 70 FR 39104, 

39172 (July 6, 2005) (stating that emissions limits 

including BART are to be met on a ‘‘continuous 

basis’’ in the BART Guidelines, section V); 42 

U.S.C. 7602(k) (noting that emission limits are to be 

on ‘‘a continuous basis’’). 

199PacifiCorp BART Analysis for Hunter Unit 2, 

pp. 2.b–105—2.a–122 (2012). 

200Srivastava, R., Hall, R., Khan, S., Lani, B., & 

Culligan, K., Nitrogen Oxides Emission Control 

Options for Coal-Fired Utility Boilers, 55 J. Air & 

Waste Mgmt. Assoc. 1367, 1385–86 (2005). 

Unit 1, LNB and SOFA with SCR is very 

cost-effective, at $2,380/ton on an 

average basis (counting the costs and 

emission reductions from the 

combination of the three control 

technology elements) and at $5,268/ton 

on an incremental basis compared to 

LNB with SOFA and SNCR. Compared 

to LNB with SOFA, the incremental cost 

effectiveness is $4,813/ton, which also 

compares favorably to the incremental 

cost effectiveness that supported the 

selection of LNB with SOFA and SCR 

for Laramie River Station. For Hunter 

Unit 1, LNB and SOFA with SCR 

provides substantial visibility benefits at 

several Class I areas that are similar to 

those from Laramie River Station and 

larger than those from Dave Johnson 

Units 3 and 4. For example, the 

visibility improvement from that control 

option installed on a single unit is 1.342 

dv at Arches NP, 1.545 dv at 

Canyonlands NP, and 1.113 at Capitol 

Reef NP. These comparisons show that 

costs are justified in light of the 

substantial visibility benefits, both total 

and incremental. 

In the case of Hunter, the unit level 

visibility improvements justify the most 

stringent level of control, SCR, for each 

of the two Hunter units. Necessarily, 

when we consider the source-wide 

visibility improvements, they will be 

larger and also justify the most stringent 

level of control. In addition, the unit 

level visibility improvements and 

source-wide visibility improvements (as 

derived by summing the unit level 

visibility improvements) at other 

impacted Class I areas, particularly 

Arches NP and Capitol Reef NP, support 

the most stringent level of control. 

Accordingly, for Hunter Unit 1, we 

propose to find that BART for NOX is 

LNB and SOFA with SCR, represented 

by an emission limit of 0.07 lb/MMBtu 

(30-day rolling average). The proposed 

BART emission limit of 0.07 lb/MMBtu 

allows for a sufficient margin of 

compliance for a 30-day rolling average 

limit that would apply at all times, 

including startup, shutdown, and 

malfunction.198 We are also proposing 

monitoring, recordkeeping, and 

reporting requirements as described in 

our proposed regulatory text for 40 CFR 

52.2336. 

Under 40 CFR 51.308(e)(1)(iv), ‘‘each 

source subject to BART [is] required to 

install and operate BART as 

expeditiously as practicable, but in no 

event later than five years after approval 

of the implementation plan revision.’’ In 

light of the considerable effort involved 

to retrofit SCR, we propose that five 

years is as expeditiously as practicable. 

Therefore, we propose a compliance 

deadline of five years from the date our 

final FIP becomes effective. 

b. Hunter Unit 2 

Generally speaking, Hunter Unit 2 is 

identical to Hunter Unit 1. The Hunter 

Unit 2 boiler is of tangential-fired design 

with newer generation low-NOX burners 

and separated overfire air which were 

installed in spring 2011. Hunter Unit 2 

currently achieves an annual emission 

rate of approximately 0.20 lb/MMBtu 

with these combustion controls. Under 

Utah’s submitted regional haze SIP, Unit 

1 is subject to a state-law NOX emission 

limit of 0.26 lb/MMBtu on a 30-day 

rolling average. Prior to the installation 

of LNB and SOFA the unit operated 

with an actual annual emission rate of 

about 0.38 lb/MMBtu. 

Step 1: Identify All Available NOX

Control Technologies 

For the same reasons as for Hunter 

Unit 1, we propose to adopt the 

identification of available NOX control 

technologies in PacifiCorp’s 2012 BART 

analysis to satisfy Step 1, and we refer 

the reader to the 2012 PacifiCorp BART 

analysis for details on those control 

technologies. 

Step 2: Eliminate Technically Infeasible 

Options 

In its 2012 BART analysis,199

PacifiCorp eliminated available NOX

control technologies that PacifiCorp 

evaluated as technologically infeasible 

for Hunter Unit 2. The remaining 

technologically feasible control 

technologies are the combustion 

controls, LNB and SOFA, and the postcombustion controls, SNCR and SCR. 

As with Hunter Unit 1, we agree with 

PacifiCorp’s evaluation of 

technologically available controls for 

Hunter Unit 2 and propose to adopt it 

for Step 2. 

Step 3: Evaluate Control Effectiveness of 

Remaining Control Technologies 

As noted previously, Hunter Unit 2 is 

currently achieving an actual annual 

emission rate of approximately 0.20 lb/ 

MMBtu with LNB and SOFA. This 

represents a 48.2 percent reduction from 

the baseline emission rate of 0.38 lb/

MMBtu. 

SCR can achieve performance 

emission rates as low as 0.04 to 0.07 lb/ 

MMBtu on an annual basis.200 For this 

analysis, consistent with our actions 

elsewhere, as well with PacifiCorp’s 

analysis, we use an annual emission rate 

of 0.05 lb/MMBtu for SCR, which when 

combined with LNB and SOFA achieves 

an overall control efficiency of 86.9 

percent. For this analysis, consistent 

with our actions elsewhere, as well with 

PacifiCorp’s analysis, we use an annual 

emission rate of 0.05 lb/MMBtu for SCR, 

which when combined with LNB and 

SOFA achieves an overall control 

efficiency of 86.9 percent. 

As with Hunter Unit 1, we evaluated 

post-combustion control technologies, 

SNCR and SCR, in combination with 

combustion controls. Our evaluation is 

the same as for Hunter Unit 1. A 

summary of emissions projections for 

the control options evaluated is 

provided in Table 19. 

TABLE 19—SUMMARY OF NOX BART ANALYSIS CONTROL TECHNOLOGIES FOR HUNTER UNIT 2 

Control option 

Control 

effectiveness 

(%) 

Annual emission 

rate 

(lb/MMBtu) 

Emissions 

reduction 

(tpy) 

Remaining 

emissions 

(tpy) 

LNB/SOFA+SCR ...................................................................... 86.9 0.05 5,230 788 

LNB/SOFA+SNCR ................................................................... 59.2 0.16 3,562 2,457 

LNB/SOFA ............................................................................... 48.2 0.20 2,902 3,117 

Baseline 1 ................................................................................. .............................. 0.38 .............................. 6,018 

1Baseline emissions were determined by averaging the annual emissions from 2001 to 2003 as reported to EPA Air Markets Program Data 

available at http://ampd.epa.gov/ampd/. 

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201See 79 FR 5032, 5133 (Jan. 30, 2014) 

(discussing reasons for rejecting use of AFUDC). 

Step 4: Evaluate Impacts and Document 

Results 

Part 1—Costs of Compliance 

We obtained capital costs for LNB and 

SOFA from the 2014 PacifiCorp BART 

analysis. PacifiCorp did not report any 

operating and maintenance costs for 

LNB and SOFA. Similarly, we obtained 

capital cost estimates for LNB and 

SOFA with SNCR from the 2014 

PacifiCorp BART analysis. However, for 

operating and maintenance costs we 

propose to rely on the draft 2015 draft 

SNCR chapter of the CCM. Refer to the 

ATP report for details. Capital costs for 

LNB and SOFA with SCR were also 

obtained from the 2014 PacifiCorp 

BART analysis. However, PacifiCorp’s 

capital costs were adjusted to account 

for items that were double-counted or 

should not be allowed under the CCM, 

such as AFUDC.201 In addition, the 

capital costs were adjusted to account 

for a significant overestimation of the 

catalyst volume and related costs. These 

adjustments are documented in the ATP 

report and associated spread sheet. A 

discussion of operating and 

maintenance costs of SCR is also 

included in the ATP report. For the 

reasons given in the report, we propose 

to adopt the cost estimates contained in 

it. 

A summary of our proposed cost 

estimates for all control options is 

presented in Table 20. 

TABLE 20—SUMMARY OF NOX BART COSTS ON HUNTER UNIT 2 

Control option Total capital 

investment 

Indirect annual 

cost Direct annual cost Total annual cost 

Emissions 

reductions 

(tpy) 

Average cost 

effectiveness 

($/ton) 

LNB/SOFA ........... $8.6M $0.9M $0M $0.9M 2,902 $298 

LNB/SOFA/SNCR 16.0M 1.6M 1.9M 3.5M 3,562 968 

LNB/SOFA/SCR ... 108.1M 10.3 2.4M 12.7M 5,230 2,432 

Parts 2 and 3—Energy and Non-Air 

Quality Environmental Impacts of 

Compliance 

The energy and non-air quality 

impacts for Hunter Unit 2 are nearly 

identical to those for Hunter Unit 1 as 

discussed previously. Accordingly, for 

the same reasons as for Hunter Unit 1, 

we propose to determine that we have 

adequately considered these impacts by 

including cost of additional energy in 

cost effectiveness and assessing non-air 

quality environmental impacts as 

insufficient to eliminate or weigh 

against any of the BART options. 

Part 4—Remaining Useful Life 

PacifiCorp assumes a remaining 

useful life of at least 20 years for Hunter 

Unit 2 in its BART analysis, and has not 

indicated any intention to retire, or 

curtail generation from, Hunter Unit 2. 

Therefore, this factor does not preclude 

any of the control options considered. In 

addition, this factor is consistent with 

our BART calculation of cost 

effectiveness because annualized costs 

have been calculated over a 20 year 

period for each of the control options 

considered. We propose that this gives 

adequate consideration to this factor. 

Step 5: Evaluate Visibility Impacts 

Table 21 presents the highest of the 

98th percentile visibility improvements 

at the affected Class I areas for the three 

meteorological years modeled, 2001 

through 2003. Tables 22 and 23 present 

the number of days (summed across 

three years) with impacts greater than 

the contribution and causation 

thresholds—0.5 dv and 1.0 dv, 

respectively. 

TABLE 21—HUNTER UNIT 2—VISIBILITY IMPROVEMENTS

Class I area LNB with SOFA 

(Ddv) 

LNB with SOFA 

and SNCR 

(Ddv) 

LNB with SOFA 

and SCR 

(Ddv) 

Arches NP .................................................................................................................. 0.569 0.711 1.080 

Black Canyon of the Gunnison NP ........................................................................... 0.153 0.189 0.279 

Bryce Canyon NP ...................................................................................................... 0.234 0.291 0.429 

Canyonlands NP ........................................................................................................ 0.658 0.822 1.250 

Capitol Reef NP ......................................................................................................... 0.491 0.623 0.879 

Flat Tops WA ............................................................................................................. 0.180 0.223 0.328 

Grand Canyon NP ..................................................................................................... 0.275 0.340 0.506 

Mesa Verde NP ......................................................................................................... 0.182 0.225 0.344 

Zion NP ...................................................................................................................... 0.144 0.178 0.262 

TABLE 22—HUNTER UNIT 2—DAYS GREATER THAN 0.5 DECIVIEW

[Three Year Total] 

Class I area Baseline 

(days) 

LNB with SOFA 

(days) 

LNB with SOFA 

and SNCR 

(days) 

LNB with SOFA 

and SCR 

(days) 

Arches NP ................................................................................ 293 276 268 245 

Black Canyon of the Gunnison NP ......................................... 68 57 55 49 

Bryce Canyon NP .................................................................... 42 39 37 30 

Canyonlands NP ...................................................................... 359 336 331 317 

Capitol Reef NP ....................................................................... 175 163 161 152 

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TABLE 22—HUNTER UNIT 2—DAYS GREATER THAN 0.5 DECIVIEW—Continued 

[Three year total] 

Class I area Baseline 

(days) 

LNB with SOFA 

(days) 

LNB with SOFA 

and SNCR 

(days) 

LNB with SOFA 

and SCR 

(days) 

Flat Tops WA ........................................................................... 77 64 63 57 

Grand Canyon NP ................................................................... 49 46 45 40 

Mesa Verde NP ....................................................................... 82 72 66 59 

Zion NP .................................................................................... 29 24 23 22 

TABLE 23—HUNTER UNIT 2—DAYS GREATER THAN 1.0 DECIVIEW

[Three year total] 

Class I area Baseline 

(days) 

LNB with SOFA 

(days) 

LNB with SOFA 

and SNCR 

(days) 

LNB with SOFA 

and SCR 

(days) 

Arches NP ................................................................................ 170 151 145 131 

Black Canyon of the Gunnison NP ......................................... 22 16 13 11 

Bryce Canyon NP .................................................................... 22 21 19 16 

Canyonlands NP ...................................................................... 240 221 218 198 

Capitol Reef NP ....................................................................... 118 113 111 105 

Flat Tops WA ........................................................................... 31 20 20 14 

Grand Canyon NP ................................................................... 32 25 25 22 

Mesa Verde NP ....................................................................... 32 22 20 14 

Zion NP .................................................................................... 14 11 9 8 

Select BART. A summary of our impacts analysis 

for Hunter Unit 2 is presented in Table 

24. 

TABLE 24—SUMMARY OF HUNTER UNIT 2 IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/MMBtu) 

Emission 

reduction 

(tpy) 

Total 

annual 

costs 

(million$) 

Average 

cost 

effectiveness 

($/ton) 

Incremental 

cost 

effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days > 

0.5 dv 

Days > 

1.0 dv 

LNB with SOFA ........ 0.20 2,902 $0.9M $298 ................................... 0.658 336 221 

LNB with SOFA and 

SNCR.

0.16 3,562 3.5M 968 $3,913 ....................... 0.822 331 218 

LNB with SOFA and 

SCR.

0.05 5,230 12.7M 2,432 $5,558 (compared to 

LNB with SOFA 

and SNCR).

$5,092 (compared to 

LNB with SOFA). 

1.250 317 198 

* At the most impacted Class I area, Canyonlands National Park. 

In determining what to co-propose as 

BART, we have taken into consideration 

all five of the statutory factors required 

by the CAA: The costs of compliance, 

the energy and non-air quality 

environmental impacts of compliance, 

any existing pollution control 

technology in use at the source, the 

remaining useful life of the source, and 

the degree of improvement in visibility 

which may reasonably be anticipated to 

result from the use of such technology. 

Later on we provide a justification for 

our selection of BART, including an 

explanation of how each of the CAA 

factors was used in that selection. 

We have considered the energy and 

non-air quality environmental impacts 

of compliance and propose to find that 

they do not appreciably favor one 

control option over another, or preclude 

a particular control option from 

selection. As explained for Hunter Unit 

1, the existing pollution controls have 

been accounted for in our evaluation of 

BART, and also would not favor or 

preclude any of the control options 

considered. And finally, we have 

considered the remaining useful life of 

the source and find that it is sufficiently 

long (greater than 20 years) so as not to 

favor or preclude any of the control 

options. As a result, the remaining 

factors—the costs of compliance and 

visibility improvement—are the primary 

factors that lead us to our proposed 

BART selection for Hunter Unit 2. 

In order to select BART we propose 

(for the same reasons as for Hunter Unit 

1) to weigh the costs of compliance 

against visibility impacts by generally 

comparing them with BART 

determinations that have been made 

elsewhere. Specifically, we propose to 

compare the average cost-effectiveness, 

incremental cost-effectiveness, visibility 

improvement, and incremental visibility 

improvement for LNB and SOFA with 

SCR with BART determinations where 

the EPA and States have based their 

determination on the same metrics. The 

most comparable determinations are the 

same as for Hunter Unit 1: Laramie 

River Station, Hayden Station, and 

Cholla Power Plant. 

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202Emission limits such as BART are required to 

be met on a continuous basis. See 70 FR 39104, 

39172 (July 6, 2005) (stating that emissions limits 

including BART are to be met on a ‘‘continuous 

basis’’ in the BART Guidelines, section V); 42 

U.S.C. 7602(k) (noting that emission limits are to be 

on ‘‘a continuous basis’’). 

203See U.S. Energy Information Administration, 

Electric Generating Capacity for 2011 (taken from 

Form EIA–860). See ‘‘EIA existing generating units 

2011.xls’’ spreadsheet in the docket. 

204See 40 CFR 51.302(e)(1)(ii)(B) (‘‘The 

determination of BART for fossil-fuel fired power 

plants having a total generating capacity greater 

than 750 megawatts must be made pursuant to the 

guidelines in appendix Y of this part.’’). 

205 40 CFR part 51, appendix Y, IV.E.5, Table. 1. 

206See 40 CFR 51.301 (defining BART); 40 CFR 

51.308(e). 

207See PacifiCorp BART Analysis for Huntington 

Unit 1(2012); PacifiCorp BART Analysis for 

Huntington Unit 2 (2012); see also Chapter 2 of the 

Technical Support Document for Utah’s Regional 

Haze BART Submittal; PacifiCorp’s BART Analysis 

Update for Hunter Units 1 and 2 and Huntington 

Units 1 and 2 (2014). 

208PacifiCorp BART Analysis for Huntington 

Unit 1, p. 2.c-60 (2012). 

209 40 CFR part 51 appendix Y. 

210PacifiCorp BART Analysis for Huntington 

Unit 1, pp. 2.c–61—2.c–77 (2012). 

Based on these comparisons, we think 

LNB and SOFA with SCR for Hunter 2 

is fully consistent with the other BART 

determinations. LNB and SOFA with 

SCR is very cost-effective at $2,432/ton, 

and provides substantial visibility 

benefits at several Class I areas. For 

example, the visibility improvement 

from that control option is 1.250 dv at 

Canyonlands NP and 1.080 dv at Arches 

NP. The incremental cost-effectiveness 

of SCR, $5,558/ton, is by comparison 

also reasonable. This comparison also 

shows that costs are justified in light of 

the substantial visibility benefits, both 

total and incremental. 

In the case of Hunter, the unit level 

visibility improvements justify the most 

stringent level of control, SCR, for each 

of the two Hunter units. Necessarily, 

when we consider the source-wide 

visibility improvements, they will be 

larger and also justify the most stringent 

level of control. In addition, the unit 

level visibility improvements and 

source-wide visibility improvements (as 

derived by summing the unit level 

visibility improvements) at other 

impacted Class I areas, particularly 

Arches NP and Capitol Reef NP, support 

the most stringent level of control. 

Accordingly, for Hunter Unit 2, we 

propose to find that BART for NOX is 

LNB and SOFA with SCR, represented 

by an emission limit of 0.07 lb/MMBtu 

(30-day rolling average). The proposed 

BART emission limit of 0.07 lb/MMBtu 

allows for a sufficient margin of 

compliance for a 30-day rolling average 

limit that would apply at all times, 

including startup, shutdown, and 

malfunction.202 We are also proposing 

monitoring, recordkeeping, and 

reporting requirements as described in 

our proposed regulatory text for 40 CFR 

52.2336. 

Under 40 CFR 51.308(e)(1)(iv), ‘‘each 

source subject to BART [is] required to 

install and operate BART as 

expeditiously as practicable, but in no 

event later than 5 years after approval of 

the implementation plan revision.’’ In 

light of the considerable effort involved 

to retrofit SCR, we propose that five 

years is as expeditiously as practicable. 

Therefore, we propose a compliance 

deadline of five years from the date our 

final FIP becomes effective. 

3. Huntington Power Plant 

As described previously in section 

IV.A, Huntington Units 1 and 2 were 

determined to be subject to BART. 

PacifiCorp’s Huntington Power Plant 

(Huntington), is located in Huntington 

City, Utah, and consists of a total of the 

two electric utility steam generating 

units. Huntington Units 1 and 2 have a 

nameplate generating capacity of 498 

MW each.203 The boilers are 

tangentially fired pulverized coal 

boilers, burning bituminous coal from 

the nearby Deer Creek Mine. 

Our evaluation of BART for 

Huntington Unit 1 and 2 follows the 

Guidelines for BART Determinations 

Under the Regional Haze Rule, which 

are found in appendix Y to 40 CFR part 

51. For Huntington Units 1 and 2, the 

BART Guidelines are mandatory 

because the combined capacity for all 

units at the Huntington facility is greater 

than 750 MW.204 Under the Guidelines, 

cost estimates for control technologies 

should be based on the CCM, where 

possible. 

The BART Guidelines establish 

presumptive NOX limits for coal-fired 

EGUs greater than 200 MW located at 

greater than 750 MW power plants that 

are operating without post-combustion 

controls. For the tangential-fired boilers 

burning bituminous coal at Huntington, 

that presumptive limit is 0.28 lb/

MMBtu.205 The BART Guidelines 

provide that the five factor analysis may 

result in a limit that is different than the 

presumptive limit, and the presumptive 

limits do not obviate the need to 

determine BART on a case-by-case basis 

considering the five factors.206

PacifiCorp provided BART analyses 

for Huntington 1 and 2 to Utah in 2012 

and 2014 which we utilize in our 

proposed BART evaluation here.207

Although we are using some 

information provided by Utah and 

PacifiCorp, we have independently 

evaluated all five statutory BART 

factors. 

a. Huntington Unit 1 

The Huntington Unit 1 boiler is of 

tangential-fired design with newer 

generation low-NOX burners and 

separated overfire air which were 

installed in fall 2010. Huntington Unit 

1 currently achieves an annual emission 

rate of approximately 0.22 lb/MMBtu 

with these combustion controls. Under 

Utah’s submitted regional haze SIP, Unit 

1 is subject to a state-law NOX emission 

limit of 0.26 lb/MMBtu on a 30-day 

rolling average. Prior to the installation 

of LNB and SOFA the unit operated 

with an actual annual emission rate of 

about 0.37 lb/MMBtu. 

Step 1: Identify All Available NOX

Control Technologies 

In its 2012 BART analysis for 

Huntington Unit 1, PacifiCorp identified 

several NOX control technologies, both 

for combustion controls and postcombustion controls.208 The 

combustion controls identified by 

PacifiCorp include: Low-NOX burners 

and separated overfire air (LNB and 

SOFA overfire air; already installed), 

rotating overfire air, neural network 

optimization system, flue gas 

recirculation, gas reburn, fuel lean gas 

reburn, coal switching, water injection, 

and others. Post-combustion control 

options identified by PacifiCorp 

include: SNCR, RRI, SCR, and others. 

We note that the combustion controls, 

LNB and SOFA, have already been 

installed on Huntington Unit 1, and so 

we consider them here as ‘‘any existing 

controls’’ under the third statutory 

factor. In addition, the BART Guidelines 

recognize that ‘‘[c]ombinations of 

inherently lower-emitting processes and 

add-on controls’’ are a category of 

retrofit controls which can be 

considered.209 Accordingly, the 

inherently lower-emitting combustion 

controls, LNB and SOFA, are evaluated 

in combination with the add-on 

controls, SNCR and SCR. 

We have reviewed PacifiCorp’s review 

of NOX control technologies and find it 

to be comprehensive. We propose to 

adopt it to satisfy Step 1 and we refer 

to the 2012 PacifiCorp BART analysis 

for details on the available NOX control 

technologies. 

Step 2: Eliminate Technically Infeasible 

Options 

In its 2012 BART analysis,210

PacifiCorp eliminated available NOX

control technologies that PacifiCorp 

evaluated as technologically infeasible 

for Huntington Unit 1. The remaining 

technologically feasible control 

technologies are the combustion 

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211 Institute of Clean Air Companies, White Paper, 

SNCR for Controlling NOX Emissions, pp. 4, 9 (Feb. 

2008). 

212See [DRAFT] 2015 SNCR CCM (July 2015), 

Figure 1.1c: SNCR NOX Reduction Efficiency 

Versus Baseline NOX Levels for Coal-fired Utility 

Boilers. 213Srivastava, R., Hall, R., Khan, S., Lani, B., & 

Culligan, K., Nitrogen Oxides Emission Control 

Options for Coal-Fired Utility Boilers, 55 J. Air & 

Waste Mgmt. Assoc. 1367, 1367–88 (2005). 

214See 79 FR 5032, 5133 (Jan. 30, 2014) 

(discussing reasons for rejecting use of AFUDC). 

215EPA Air Pollution Control Cost Manual, pp. 1– 

21 (6th ed. 2002). 

controls, LNB and SOFA, and the postcombustion controls, SNCR and SCR. 

We agree with PacifiCorp’s evaluation 

of technologically available controls for 

Huntington Unit 1 and propose to adopt 

it for Step 2. 

Step 3: Evaluate Control Effectiveness of 

Remaining Control Technologies 

As noted previously, Huntington Unit 

1 is currently achieving an actual 

annual emission rate of approximately 

0.22 lb/MMBtu with LNB and SOFA. 

This represents a 41.5 percent reduction 

from the baseline emission rate of 0.37 

lb/MMBtu. 

The post-combustion control 

technologies, SNCR and SCR, have been 

evaluated in combination with 

combustion controls. That is, the inlet 

concentration to the post-combustion 

controls is assumed to be 0.22 lb/

MMBtu (annual). This allows the 

equipment and operating and 

maintenance costs of the postcombustion controls to be minimized 

based on the lower inlet NOX

concentration. 

Typically, SNCR reduces NOX an 

additional 20 to 30 percent above 

combustion controls without excessive 

NH3 slip.211 For this analysis, the 

control efficiency of SNCR has been 

calculated based on the formula in the 

2015 draft CCM SNCR chapter,212 which 

for Huntington Unit 1 yields an 

additional reduction of 21.7 percent 

after combustion controls. When 

combined with LNB and SOFA, SNCR 

is anticipated to achieve an annual 

emission rate of 0.17 lb/MMBtu, 

corresponding to an overall control 

efficiency of 54.2 percent. 

SCR can achieve performance 

emission rates as low as 0.04 to 0.07 lb/ 

MMBtu on an annual basis.213 For this 

analysis, consistent with our actions 

elsewhere, as well with PacifiCorp’s 

analysis, we use an annual emission rate 

of 0.05 lb/MMBtu for SCR, which when 

combined with LNB and SOFA achieves 

an overall control efficiency of 86.7 

percent. 

A summary of emissions projections 

for the control options evaluated is 

provided in Table 25. 

TABLE 25—SUMMARY OF NOX BART ANALYSIS CONTROL TECHNOLOGIES FOR HUNTINGTON UNIT 1 

Control option 

Control 

effectiveness 

(%) 

Annual 

emission rate 

(lb/MMBtu) 

Emissions 

reduction 

(tpy) 

Remaining 

emissions 

(tpy) 

LNB/SOFA +SCR ............................................................................................ 86.7 0.05 5,092 784 

LNB/SOFA +SNCR .......................................................................................... 54.2 0.17 3,185 2,692 

LNB/SOFA ....................................................................................................... 41.5 0.22 2,440 3,436 

Baseline 1 ......................................................................................................... ........................ 0.37 ........................ 5,876 

1Baseline emissions were determined by averaging the annual emissions from 2001 to 2003 as reported to EPA Air Markets Program Data 

available at http://ampd.epa.gov/ampd/. 

Step 4: Evaluate Impacts and Document 

Results 

Part 1—Costs of Compliance 

We obtained capital costs for LNB and 

SOFA from the 2014 PacifiCorp BART 

analysis. PacifiCorp did not report any 

operating and maintenance costs for 

LNB and SOFA. Similarly, we obtained 

capital cost estimates for LNB and 

SOFA with SNCR from the 2014 

PacifiCorp BART analysis. However, for 

operating and maintenance costs we 

propose to rely on the draft 2015 draft 

SNCR chapter of the CCM. Refer to the 

ATP report for details. Capital costs for 

LNB and SOFA with SCR were also 

obtained from the 2014 PacifiCorp 

BART analysis. However, PacifiCorp’s 

capital costs were adjusted to account 

for items that were double-counted or 

should not be allowed under the CCM, 

such as AFUDC.214 In addition, the 

capital costs were adjusted to account 

for a significant overestimation of the 

catalyst volume and related costs. These 

adjustments are documented in the ATP 

report and associated spread sheet. A 

discussion of operating and 

maintenance costs of SCR is also 

included in the ATP report. For the 

reasons given in the report, we propose 

to adopt the cost estimates contained in 

it. 

A summary of our proposed cost 

estimates for all control options is 

presented in Table 26. 

TABLE 26—SUMMARY OF NOX BART COSTS ON HUNTINGTON UNIT 1 

Control option Total capital 

investment 

Indirect annual 

cost 

Direct annual 

cost 

Total annual 

cost 

Emissions 

reductions 

(tpy) 

Average Cost 

effectiveness 

($/ton) 

LNB/SOFA ............................................... $8.1M $0.8M $0M $0.8M 2,440 $332 

LNB/SOFA/SNCR .................................... 15.5M 1.5M 2.0M 3.5M 3,185 1,098 

LNB/SOFA/SCR ....................................... 107.8M 10.3M 2.5M 12.8M 5,092 2,515 

Parts 2 and 3—Energy and Non-Air 

Quality Environmental Impacts of 

Compliance 

SNCR slightly reduces the thermal 

efficiency of a boiler as the reduction 

reaction uses thermal energy from the 

boiler, decreasing the energy available 

for power generation.215 Using the CCM, 

we have calculated the electrical power 

consumption of SNCR to be 361,000 

kW-hr per year for Huntington Unit 1. 

For SCR, the thermal efficiency is 

much more reduced because the new 

ductwork and the reactor’s catalyst 

layers decrease the flue gas pressure. As 

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a result, additional fan power is 

necessary to maintain the flue gas flow 

rate through the ductwork and reactor. 

Using the CCM, we have calculated the 

electrical power consumption of SCR to 

be approximately 18,617,000 kW-hr per 

year for Huntington Unit 1. 

Both SCR and SNCR require some 

minimal electricity to service 

pretreatment and injection equipment, 

pumps, compressors, and control 

systems. The energy requirements 

described earlier are not significant 

enough to warrant elimination of either 

SNCR or SCR as BART. In addition, the 

cost of the additional energy 

requirements has been included in our 

cost effectiveness calculations. 

SNCR and SCR will slightly increase 

the quantity of ash that will need to be 

disposed. In addition, transportation 

and storage of chemical reagents may 

result in spills or releases. However, 

these non-air quality environmental 

impacts do not warrant elimination of 

either SNCR or SCR as BART. 

There are no additional energy 

requirements associated with the new 

LNB and SOFA, and no significant nonair quality environmental impacts. 

In summary, we propose to determine 

that we have adequately considered 

these impacts by including cost of 

additional energy in cost effectiveness 

and assessing non-air quality 

environmental impacts as insufficient to 

eliminate or weigh against any of the 

BART options. 

Part 4—Remaining Useful Life 

PacifiCorp assumes a remaining 

useful life of at least 20 years for 

Huntington Unit 1 in its BART analysis, 

and has not indicated any intention to 

retire, or curtail generation from, 

Huntington Unit 1. Therefore, this factor 

does not preclude any of the control 

options considered. In addition, this 

factor does not impact our BART 

calculation of cost effectiveness because 

annualized costs have been calculated 

over a 20 year period for each of the 

control options considered. We propose 

that this gives adequate consideration to 

this factor. 

Step 5: Evaluate Visibility Impacts 

Table 27 presents the highest of the 

98th percentile visibility improvements 

at the affected Class I areas for the three 

meteorological years modeled, 2001 

through 2003. Tables 28 and 29 present 

the number of days (summed across 

three years) with impacts greater than 

the contribution and causation 

thresholds—0.5 dv and 1.0 dv, 

respectively. 

TABLE 27—HUNTINGTON UNIT 1—VISIBILITY IMPROVEMENTS

Class I Area 

LNB with 

SOFA 

(Ddv) 

LNB with 

SOFA and 

SNCR 

(Ddv) 

LNB with 

SOFA and 

SCR 

(Ddv) 

Arches NP .................................................................................................................................... 0.684 0.907 1.488 

Black Canyon of the Gunnison NP ............................................................................................. 0.156 0.205 0.328 

Bryce Canyon NP ........................................................................................................................ 0.222 0.292 0.473 

Canyonlands NP .......................................................................................................................... 0.851 1.133 1.881 

Capitol Reef NP ........................................................................................................................... 0.493 0.651 1.108 

Flat Tops WA ............................................................................................................................... 0.181 0.239 0.383 

Grand Canyon NP ....................................................................................................................... 0.200 0.262 0.419 

Mesa Verde NP ........................................................................................................................... 0.215 0.284 0.462 

Zion NP ........................................................................................................................................ 0.150 0.198 0.320 

TABLE 28—HUNTINGTON UNIT 1—DAYS GREATER THAN 0.5 DECIVIEW

[Three year total] 

Class I Area Baseline 

(days) 

LNB with 

SOFA 

(days) 

LNB with 

SOFA and 

SNCR 

(days) 

LNB with 

SOFA and 

SCR 

(days) 

Arches NP ........................................................................................................ 237 221 210 180 

Black Canyon of the Gunnison NP .................................................................. 45 33 30 23 

Bryce Canyon NP ............................................................................................ 36 26 25 19 

Canyonlands NP .............................................................................................. 277 249 244 210 

Capitol Reef NP ............................................................................................... 131 117 116 99 

Flat Tops WA ................................................................................................... 64 41 37 27 

Grand Canyon NP ........................................................................................... 40 35 34 27 

Mesa Verde NP ............................................................................................... 63 46 41 30 

Zion NP ............................................................................................................ 21 16 16 14 

TABLE 29—HUNTINGTON UNIT 1—DAYS GREATER THAN 1.0 DECIVIEW

[Three year total] 

Class I Area Baseline 

(days) 

LNB with 

SOFA 

(days) 

LNB with 

SOFA and 

SNCR 

(days) 

LNB with 

SOFA and 

SCR 

(days) 

Arches NP ........................................................................................................ 146 121 117 86

Black Canyon of the Gunnison NP .................................................................. 16 7 7 3 

Bryce Canyon NP ............................................................................................ 19 13 9 5 

Canyonlands NP .............................................................................................. 175 153 143 117 

Capitol Reef NP ............................................................................................... 91 74 69 55 

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216See 79 FR 5032, 5105–1 (Jan. 30, 2012). 

217 79 FR 5032, 5047 (Jan. 30, 2014). 

218 79 FR 5032, 5049. 

TABLE 29—HUNTINGTON UNIT 1—DAYS GREATER THAN 1.0 DECIVIEW—Continued 

[Three year total] 

Class I Area Baseline 

(days) 

LNB with 

SOFA 

(days) 

LNB with 

SOFA and 

SNCR 

(days) 

LNB with 

SOFA and 

SCR 

(days) 

Flat Tops WA ................................................................................................... 17 9 8 3 

Grand Canyon NP ........................................................................................... 19 13 12 9 

Mesa Verde NP ............................................................................................... 22 13 10 4 

Zion NP ............................................................................................................ 11 8 6 4 

Select BART. A summary of our impacts analysis 

for Huntington Unit 1 is presented in 

Table 30. 

TABLE 30—SUMMARY OF HUNTINGTON UNIT 1 IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate 

(lb/MMBtu) 

Emission 

reduction 

(tpy) 

Total annual 

costs 

(million$) 

Average cost 

effectiveness 

($/ton) 

Incremental cost 

effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days > 

0.5 dv 

Days > 

1.0 dv 

LNB with SOFA .... 0.22 2,440 $0.8M $332 ............................... 0.851 249 153 

LNB with SOFA 

and SNCR.

0.17 3,185 3.5M 1,098 3,609 ..................... 1.113 244 143 

LNB with SOFA 

and SCR.

0.05 5,092 12.8M 2,515 $4,879 (compared 

to LNB with 

SOFA and 

SNCR).

$4,522 (compared 

to LNB with 

SOFA).

1.881 210 117 

* At the most impacted Class I area, Canyonlands National Park. 

In determining what to co-propose as 

BART, we have taken into consideration 

all five of the statutory factors required 

by the CAA: The costs of compliance, 

the energy and non-air quality 

environmental impacts of compliance, 

any existing pollution control 

technology in use at the source, the 

remaining useful life of the source, and 

the degree of improvement in visibility 

which may reasonably be anticipated to 

result from the use of such technology. 

Later on we provide a justification for 

our selection of BART, including an 

explanation of how each of the CAA 

factors was used in that selection. 

As described in step 1 previously, we 

have considered the existing pollution 

control technology in use at the source. 

We note that Huntington Unit 1 was 

equipped with LNB and SOFA in the 

fall of 2010 in order to meet state-law 

requirements in the 2011 Utah RH SIP 

submittal, which we did not approve. In 

this co-proposal we have to evaluate 

control technologies and baseline 

emissions from the correct starting 

point, that is, prior to the installation of 

the combustion controls pursuant to 

state-law NOX limitations.216 As a 

result, we used the period 2001–2003 as 

the appropriate period for baseline 

emissions, in order to provide a realistic 

depiction of annual emissions for 

Huntington Unit 1 prior to installation 

of combustion controls. 

We have considered the energy and 

non-air quality environmental impacts 

of compliance and propose to find that 

they do not appreciably favor one 

control option over another, or preclude 

a particular control option from 

selection. And finally, we have 

considered the remaining useful life of 

the source and find that it is sufficiently 

long (greater than 20 years) so as not to 

favor or preclude any of the control 

options. As a result, the remaining 

factors—the costs of compliance and 

visibility improvement—are the primary 

factors that lead us to our proposed 

BART selection for Huntington Unit 1. 

Having already considered the other 

factors, in order to select BART we 

propose to weigh the costs of 

compliance against visibility impacts by 

generally comparing them with BART 

determinations that have been made 

elsewhere. Specifically, we propose to 

compare the average cost-effectiveness, 

incremental cost-effectiveness, visibility 

improvement, and incremental visibility 

improvement for LNB and SOFA with 

SCR with BART determinations where 

the EPA and States have based their 

determination on the same metrics. The 

most comparable determinations are the 

same as for Hunter Unit 1. The most 

comparable determination appears to be 

in EPA’s final action for Wyoming’s 

regional haze SIP, in which EPA 

promulgated a FIP for three units at 

Laramie River Station and determined 

BART to be LNB and SOFA with SCR 

for the three units.217 On a per-unit 

basis, the visibility improvement from 

that control option was 0.52 to 0.57 dv, 

and across all three units the sum of the 

improvement was 1.62 dv. The average 

cost-effectiveness ranged from $4,375/

ton to $4,461/ton, while the incremental 

cost-effectiveness ranged from $5,449 to 

$5,871/ton. Finally, the incremental 

visibility improvement as compared to 

LNB and SOFA with SNCR was 

significant. On the other hand, at Dave 

Johnston Units 3 and 4 (for example), 

where EPA rejected LNB and SOFA 

with SCR, the incremental costeffectiveness value of LNB and SOFA 

with SCR was much higher and 

incremental visibility benefit lower than 

at Laramie River Station.218

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219 77 FR 18069 (Mar. 26, 2012) (proposal); 77 FR 

76871 (Dec. 31, 2012) (final). 220Colorado Department of Health and 

Environment, Air Pollution Control Division, Best 

Available Retrofit Technology (BART) Analysis of 

Control Options For Public Service Company— 

Hayden Station, p. 5, available at https://www.

colorado.gov/pacific/sites/default/files/AP_PO_

Hayden-Power-Plant_0.pdf. 221 77 FR 42834 (July 20, 2012) (proposal); 77 FR 

72512, 72514–15 (Dec. 5, 2012) (final). 

222We use the source-wide number here to 

compare with the Cholla determination; in addition 

as explained above we must consider source-wide 

visibility improvements. 

223Emission limits such as BART are required to 

be met on a continuous basis. See 70 FR 39104, 

39172 (July 6, 2005) (stating that emissions limits 

including BART are to be met on a ‘‘continuous 

basis’’ in the BART Guidelines, section V); 42 

U.S.C. 7602(k) (noting that emission limits are to be 

on ‘‘a continuous basis’’). 

224PacifiCorp BART Analysis for Huntington 

Unit 2, pp. 2.a–106—2.a–124 (2012). 

There are other BART determinations 

in which SCR has been selected as 

BART (either alone or in conjunction 

with LNB and SOFA) based on similar 

metrics, although those determinations 

may not have explicitly discussed 

incremental cost-effectiveness and 

incremental visibility benefits on a perunit basis. First, the State of Colorado 

selected, and the EPA approved, SCR as 

NOX BART for Public Service 

Company’s Hayden Station, Units 1 and 

2.219 Hayden Units 1 and 2 were 

equipped with first generation LNB and 

over-fire air (OFA) installed in 1999.220

In its BART determination, Colorado 

considered these existing controls as 

given and analyzed as feasible controls 

upgraded LNB, SNCR, and SCR. Based 

on an average cost-effectiveness of 

$3,385/ton and $4,064/ton, incremental 

cost-effectiveness (as compared with 

LNB and OFA with SNCR) of $5,326/ton 

and $7,331/ton, and visibility 

improvement of 1.12 dv and 0.85 dv at 

the most impacted Class I area, 

respectively, Colorado selected SCR as 

BART for Units 1 and 2. In this case, 

due to the existing controls at Hayden 

Station, the cost-effectiveness values for 

SCR for Hayden Units 1 and 2 should 

be compared to the incremental costeffectiveness values (as compared with 

LNB and SOFA, and with LNB and 

SOFA with SNCR) for SCR for 

Huntington Unit 1, and similarly for 

incremental visibility benefits. We think 

they are comparable, particularly for 

Hayden Unit 2, and considering that 

Huntington Unit 1 significantly impacts 

several Class I areas, while Colorado 

selected SCR for Hayden based solely on 

the visibility improvement at the most 

impacted Class I area, Mt. Zirkel 

Wilderness. 

Another comparable determination 

can be found in EPA’s FIP for Arizona 

Public Service’s Cholla Power Plant, 

Units 2, 3, and 4, in which EPA 

determined that NOX BART was SCR.221

Similarly to Colorado’s determination 

for Hayden, EPA considered the existing 

controls, LNB and OFA, at the three 

units and estimated average costeffectiveness values for SCR of $3,114/ 

ton, $3,472/ton, and $3,395/ton, and 

incremental cost-effectiveness values (as 

compared to LNB and OFA with SNCR) 

of $3,257/ton, $3,811/ton, and $3,661/

ton, respectively, for Units 2, 3, and 4. 

EPA’s modeling showed a source-wide 

visibility improvement for SCR of 1.34 

dv at the most impacted Class I area. 

Based on these metrics, EPA determined 

NOX BART to be SCR for the three units. 

In this case, as with Hayden, the average 

cost-effectiveness of SCR at Cholla 

should be compared with the 

incremental cost-effectiveness of SCR 

(as compared with just LNB and SOFA) 

at Huntington Unit 1. The costeffectiveness values for Huntington Unit 

1 are somewhat higher than at Cholla, 

but on the other hand the source-wide 

visibility improvement at Huntington 

Units 1 and 2 (as obtained by summing 

the per-unit improvements from Units 1 

and 2) 222 from LNB and SOFA with 

SCR is 2.759 dv at the most impacted 

Class I area, with incremental visibility 

improvements of 1.29 dv and 0.932 dv 

over LNB and SOFA and LNB and 

SOFA with SNCR, respectively. These 

visibility improvements are very much 

in line with those at Cholla, and given 

that the incremental cost-effectiveness 

of SCR at Huntington Unit 1 is still 

reasonable, the comparison with Cholla 

also supports selection of SCR for 

Huntington Unit 1. We invite comment 

on other potentially relevant BART 

determinations and our methodology 

generally. 

Based on these comparisons, we think 

LNB and SOFA with SCR is very costeffective at $2,515/ton, and provides 

substantial visibility benefits at several 

Class I areas. For example, the visibility 

improvement from that control option is 

1.488 dv at Arches NP, 1.881 dv at 

Canyonlands NP, and 1.108 dv at 

Capitol Reef NP. The incremental costeffectiveness of SCR, $4,879/ton, is by 

comparison with the Laramie River 

Station BART determination also 

reasonable. This comparison also shows 

that costs are justified in light of the 

substantial visibility benefits, both total 

and incremental. 

In the case of Huntington, the unit 

level visibility improvements justify the 

most stringent level of control, SCR, for 

each of the two Huntington units. 

Necessarily, when we consider the 

source-wide visibility improvements, 

they will be larger and also justify the 

most stringent level of control. 

Accordingly, for Huntington Unit 1, 

we propose to find that BART for NOX

is LNB and SOFA with SCR, 

represented by an emission limit of 0.07 

lb/MMBtu (30-day rolling average). The 

proposed BART emission limit of 0.07 

lb/MMBtu allows for a sufficient margin 

of compliance for a 30-day rolling 

average limit that would apply at all 

times, including startup, shutdown, and 

malfunction.223 We are also proposing 

monitoring, recordkeeping, and 

reporting requirements as described in 

our proposed regulatory text for 40 CFR 

52.2336. 

Under 40 CFR 51.308(e)(1)(iv), ‘‘each 

source subject to BART [is] required to 

install and operate BART as 

expeditiously as practicable, but in no 

event later than 5 years after approval of 

the implementation plan revision.’’ In 

light of the considerable effort involved 

to retrofit SCR, we propose that five 

years is as expeditiously as practicable. 

Therefore, we propose a compliance 

deadline of five years from the date our 

final FIP becomes effective. 

b. Huntington Unit 2 

Generally, Huntington Unit 2 is 

identical to Unit 1. The Huntington Unit 

2 boiler is of tangential-fired design 

with newer generation low-NOX burners 

and separated overfire air which were 

installed in winter 2006. Huntington 

Unit 2 currently achieves an annual 

emission rate of approximately 0.21 lb/ 

MMBtu with these combustion controls. 

Under Utah’s submitted regional haze 

SIP, Unit 2 is subject to a state-law NOX

emission limit of 0.26 lb/MMBtu on a 

30-day rolling average. Prior to the 

installation of LNB and SOFA the unit 

operated with an actual annual emission 

rate of about 0.39 lb/MMBtu. 

Step 1: Identify All Available NOX

Control Technologies 

For the same reasons as for 

Huntington Unit 1, we propose to adopt 

the identification of available NOX

control technologies in PacifiCorp’s 

2012 BART analysis to satisfy Step 1, 

and we refer the reader to the 2012 

PacifiCorp BART analysis for details on 

the available NOX control technologies. 

Step 2: Eliminate Technically Infeasible 

Options 

In its 2012 BART analysis,224

PacifiCorp eliminated available NOX

control technologies that PacifiCorp 

evaluated as technologically infeasible 

for Huntington Unit 2. The remaining 

technologically feasible control 

technologies are the combustion 

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2046 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

225 Institute of Clean Air Companies, White Paper, 

SNCR for Controlling NOX Emissions, pp. 4 and 9 

(Feb. 2008). 

226EPA Selective Noncatalytic, Reduction Cost 

Manual Draft for Public Comment, p. 1–6 (Figure 

1.1c: SNCR NOX Reduction Efficiency Versus 

Baseline NOX Levels for Coal-fired Utility Boilers) 

(June 5, 2015). 

227Srivastava, R., Hall, R., Khan, S., Lani, B., & 

Culligan, K., Nitrogen Oxides Emission Control 

Options for Coal-Fired Utility Boilers, 55 J. Air & 

Waste Mgmt Assoc. 55, 1367, 1367–88 (2005). 

228See 79 FR 5032, 5133 (discussing reasons for 

rejecting use of AFUDC). 

controls, LNB and SOFA, and the postcombustion controls, SNCR and SCR. 

We agree with PacifiCorp’s evaluation 

of technologically available controls for 

Huntington Unit 2 and propose to adopt 

it for Step 2. 

Step 3: Evaluate Control Effectiveness of 

Remaining Control Technologies 

As noted previously, Huntington Unit 

2 is currently achieving an actual 

annual emission rate of approximately 

0.21 lb/MMBtu with LNB and SOFA. 

This represents a 44.6 percent reduction 

from the baseline emission rate of 0.39 

lb/MMBtu. 

The post-combustion control 

technologies, SNCR and SCR, have been 

evaluated in combination with 

combustion controls. That is, the inlet 

concentration to the post-combustion 

controls is assumed to be 0.21 lb/

MMBtu (annual). This allows the 

equipment and operating and 

maintenance costs of the postcombustion controls to be minimized 

based on the lower inlet NOX

concentration. 

Typically, SNCR reduces NOX an 

additional 20 to 30 percent above 

combustion controls without excessive 

NH3 slip.225 For this analysis, the 

control efficiency of SNCR has been 

calculated based on the formula in the 

2015 draft CCM SNCR chapter,226 which 

for Huntington Unit 2 yields an 

additional reduction of 21.5 percent 

after combustion controls. When 

combined with LNB and SOFA, SNCR 

is anticipated to achieve an annual 

emission rate of 0.17 lb/MMBtu, 

corresponding to an overall control 

efficiency of 56.6 percent. 

SCR can achieve performance 

emission rates as low as 0.04 to 0.07 lb/ 

MMBtu on an annual basis.227 For this 

analysis, consistent with our actions 

elsewhere, as well with PacifiCorp’s 

analysis, we use an annual emission rate 

of 0.05 lb/MMBtu for SCR, which when 

combined with LNB and SOFA achieves 

an overall control efficiency of 87.0 

percent. 

A summary of emissions projections 

for the control options evaluated is 

provided in Table 31. 

TABLE 31—SUMMARY OF NOX BART ANALYSIS CONTROL TECHNOLOGIES FOR HUNTINGTON UNIT 2 

Control option 

Control 

effectiveness 

(%) 

Annual 

emission rate 

(lb/MMBtu) 

Emissions 

reduction 

(tpy) 

Remaining 

emissions 

(tpy) 

LNB/SOFA +SCR ............................................................................................ 87.0 0.05 5,023 747 

LNB/SOFA +SNCR .......................................................................................... 56.6 0.17 3,264 2,506 

LNB/SOFA ....................................................................................................... 44.6 0.21 2,576 3,194 

Baseline1 .......................................................................................................... — 0.39 — 5,770 

1Baseline emissions were determined by averaging the annual emissions from 2001 to 2003 as reported to EPA Air Markets Program Data 

available at http://ampd.epa.gov/ampd/. 

Step 4: Evaluate Impacts and Document 

Results 

Part 1—Costs of Compliance 

We obtained capital costs for LNB and 

SOFA from the 2014 PacifiCorp BART 

analysis. PacifiCorp did not report any 

operating and maintenance costs for 

LNB and SOFA. Similarly, we obtained 

capital cost estimates for LNB and 

SOFA with SNCR from the 2014 

PacifiCorp BART analysis. However, for 

operating and maintenance costs we 

propose to rely on the draft 2015 draft 

SNCR chapter of the CCM. Refer to the 

ATP report for details. Capital costs for 

LNB and SOFA with SCR were also 

obtained from the 2014 PacifiCorp 

BART analysis. However, PacifiCorp’s 

capital costs were adjusted to account 

for items that were double-counted or 

should not be allowed under the CCM, 

such as AFUDC.228 In addition, the 

capital costs were adjusted to account 

for a significant overestimation of the 

catalyst volume and related costs. These 

adjustments are documented in the ATP 

report and associated spread sheet. A 

discussion of operating and 

maintenance costs of SCR is also 

included in the ATP report. For the 

reasons given in the report, we propose 

to adopt the cost estimates contained in 

it. 

A summary of our proposed cost 

estimates for all control options is 

presented in Table 32. 

TABLE 32—SUMMARY OF NOX BART COSTS ON HUNTINGTON UNIT 2 

Control option Total capital 

investment 

Indirect annual 

costs 

Direct annual 

costs 

Total annual 

cost 

Emissions 

reductions 

(tpy) 

Average cost 

effectiveness 

($/ton) 

LNB/SOFA ............................................... $9.4M $0.9M $0M $0.9M 2,576 $365 

LNB/SOFA/SNCR .................................... 16.7M 1.6M 1.9M 3.5M 3,264 1,075 

LNB/SOFA/SCR ....................................... 109.4M 10.4M 2.4M 12.9M 5,023 2,563 

Parts 2 and 3—Energy and Non-Air 

Quality Environmental Impacts of 

Compliance 

The energy and non-air quality 

impacts for Huntington Unit 2 are 

nearly identical to those for Huntington 

Unit 1 as discussed previously. 

Accordingly, for the same reasons as for 

Huntington Unit 1, we propose to 

determine that we have adequately 

considered these impacts by including 

cost of additional energy in cost 

effectiveness and assessing non-air 

quality environmental impacts as 

insufficient to eliminate or weigh 

against any of the BART options. 

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Part 4—Remaining Useful Life 

PacifiCorp assumes a remaining 

useful life of at least 20 years for 

Huntington Unit 2 in its BART analysis, 

and has not indicated any intention to 

retire, or curtail generation from, 

Huntington Unit 2. Therefore, this factor 

does not preclude any of the control 

options considered. In addition, this 

factor does not impact our BART 

calculation of cost effectiveness because 

annualized costs have been calculated 

over a 20 year period for each of the 

control options considered. We propose 

that this gives adequate consideration to 

this factor. 

Step 5: Evaluate Visibility Impacts 

Table 33 presents the highest of the 

98th percentile visibility improvements 

at the affected Class I areas for the three 

meteorological years modeled, 2001 

through 2003. Tables 34 and 35 present 

the number of days (summed across 

three years) with impacts greater than 

the contribution and causation 

thresholds—0.5 dv and 1.0 dv, 

respectively. 

TABLE 33—HUNTINGTON UNIT 2—VISIBILITY IMPROVEMENTS

Class I Area 

LNB with 

SOFA 

(Ddv) 

LNB with 

SOFA and 

SNCR 

(Ddv) 

LNB with 

SOFA and 

SCR 

(Ddv) 

Arches NP .................................................................................................................................... 0.625 0.816 1.316 

Black Canyon of the Gunnison NP ............................................................................................. 0.143 0.184 0.292 

Bryce Canyon NP ........................................................................................................................ 0.205 0.266 0.424 

Canyonlands NP .......................................................................................................................... 0.776 1.016 1.657 

Capitol Reef NP ........................................................................................................................... 0.449 0.584 0.955 

Flat Tops WA ............................................................................................................................... 0.168 0.217 0.343 

Grand Canyon NP ....................................................................................................................... 0.183 0.236 0.371 

Mesa Verde NP ........................................................................................................................... 0.199 0.258 0.414 

Zion NP ........................................................................................................................................ 0.136 0.176 0.281 

TABLE 34—HUNTINGTON UNIT 2—DAYS GREATER THAN 0.5 DECIVIEW

[Three year total] 

Class I Area Baseline 

(days) 

LNB with 

SOFA 

(days) 

LNB with 

SOFA and 

SNCR 

(days) 

LNB with 

SOFA and 

SCR 

(days) 

Arches NP ........................................................................................................ 237 223 214 186 

Black Canyon of the Gunnison NP .................................................................. 45 35 32 26 

Bryce Canyon NP ............................................................................................ 36 26 26 23 

Canyonlands NP .............................................................................................. 277 254 244 220 

Capitol Reef NP ............................................................................................... 131 119 116 104 

Flat Tops WA ................................................................................................... 64 44 39 31 

Grand Canyon NP ........................................................................................... 40 36 35 30 

Mesa Verde NP ............................................................................................... 63 48 43 31 

Zion NP ............................................................................................................ 21 17 16 15 

TABLE 35—HUNTINGTON UNIT 2—DAYS GREATER THAN 1.0 DECIVIEW

[Three year total] 

Class I Area Baseline 

(days) 

LNB with 

SOFA 

(days) 

LNB with 

SOFA and 

SNCR 

(days) 

LNB with 

SOFA and 

SCR 

(days) 

Arches NP ........................................................................................................ 146 122 118 98

Black Canyon of the Gunnison NP .................................................................. 16 8 7 4 

Bryce Canyon NP ............................................................................................ 19 15 13 6 

Canyonlands NP .............................................................................................. 175 153 149 126 

Capitol Reef NP ............................................................................................... 91 75 70 59 

Flat Tops WA ................................................................................................... 17 9 8 4 

Grand Canyon NP ........................................................................................... 19 13 13 9 

Mesa Verde NP ............................................................................................... 22 13 13 6 

Zion NP ............................................................................................................ 11 8 6 4 

Select BART. A summary of our impacts analysis 

for Huntington Unit 2 is presented in 

Table 36. 

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2048 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

229Emission limits such as BART are required to 

be met on a continuous basis. See 70 FR 39104, 

39172 (July 6, 2005) (stating that emissions limits 

including BART are to be met on a ‘‘continuous 

basis’’ in the BART Guidelines, section V); 42 

U.S.C. 7602(k) (noting that emission limits are to be 

on ‘‘a continuous basis’’). 

TABLE 36—SUMMARY OF HUNTINGTON UNIT 2 IMPACTS ANALYSIS

Control option 

Annual 

emission 

rate (lb/

MMBtu) 

Emission 

reduction 

(tpy) 

Total annual 

costs 

($) 

Average cost 

effectiveness 

($/ton) 

Incremental cost 

effectiveness 

($/ton) 

Visibility impacts * 

Improvement 

(dv) 

Days 

>0.5 dv 

Days 

>1.0 dv 

LNB with SOFA 0.21 2,576 $0.9M $365 ........................... 0.776 254 153 

LNB with SOFA 

and SNCR.

0.17 3,264 3.5M 1,075 $3,730 .............. 1.016 244 149 

LNB with SOFA 

and SCR.

0.05 5,023 12.9M 2,563 $5,326 ..............

(compared to 

LNB with 

SOFA and 

SNCR).

$4,877 (compared to LNB 

with SOFA).

1.657 220 126 

* At the most impacted Class I area, Canyonlands National Park. 

In determining what to co-propose as 

BART, we have taken into consideration 

all five of the statutory factors required 

by the CAA: The costs of compliance, 

the energy and non-air quality 

environmental impacts of compliance, 

any existing pollution control 

technology in use at the source, the 

remaining useful life of the source, and 

the degree of improvement in visibility 

which may reasonably be anticipated to 

result from the use of such technology. 

Later on we provide a justification for 

our selection of BART, including an 

explanation of how each of the CAA 

factors was used in that selection. 

We have considered the energy and 

non-air quality environmental impacts 

of compliance and propose to find that 

they do not appreciably favor one 

control option over another, or preclude 

a particular control option from 

selection. The existing pollution 

controls have been accounted for in our 

evaluation of BART, and also would not 

favor or preclude any of the control 

options considered. And finally, we 

have considered the remaining useful 

life of the source and find that it is 

sufficiently long (greater than 20 years) 

so as not to favor or preclude any of the 

control options. As a result, the 

remaining factors—the costs of 

compliance and visibility 

improvement—are the primary factors 

that lead us to our proposed BART 

selection for Huntington Unit 2. 

In order to select BART we propose to 

weigh the costs of compliance against 

visibility impacts by generally 

comparing them with BART 

determinations that have been made 

elsewhere. Specifically, we propose to 

compare the average cost-effectiveness, 

incremental cost-effectiveness, visibility 

improvement, and incremental visibility 

improvement for LNB and SOFA with 

SCR with BART determinations where 

the EPA and States have based their 

determination on the same metrics. The 

most comparable determinations are the 

same as for Huntington Unit 1: The 

Laramie River Station, Hayden Station, 

and Cholla Power Plant determinations. 

Based on these comparisons, we think 

LNB and SOFA with SCR is very costeffective at $2,563/ton, and provides 

substantial visibility benefits at several 

Class I areas. For example, the visibility 

improvement from that control option is 

1.316 at Arches NP and 1.657 dv 

Canyonlands NP. The incremental costeffectiveness of SCR, $5,326/ton, is by 

comparison also reasonable. This 

comparison also shows that costs are 

justified in light of the substantial 

visibility benefits, both total and 

incremental. 

In the case of Huntington, the unit 

level visibility improvements justify the 

most stringent level of control, SCR, for 

each of the two Huntington units. 

Necessarily, when we consider the 

source-wide visibility improvements, 

they will be larger and also justify the 

most stringent level of control. In 

addition, the unit level visibility 

improvements and source-wide 

visibility improvements at other 

impacted Class I areas, particularly 

Arches NP and Capitol Reef NP, support 

the most stringent level of control. 

Accordingly, for Huntington Unit 2, 

we propose to find that BART for NOX

is LNB and SOFA with SCR, 

represented by an emission limit of 0.07 

lb/MMBtu (30-day rolling average). The 

proposed BART emission limit of 0.07 

lb/MMBtu allows for a sufficient margin 

of compliance for a 30-day rolling 

average limit that would apply at all 

times, including startup, shutdown, and 

malfunction.229 We are also proposing 

monitoring, recordkeeping, and 

reporting requirements as described in 

our proposed regulatory text for 40 CFR 

52.2336. 

Under § 51.308(e)(1)(iv), ‘‘each source 

subject to BART [is] required to install 

and operate BART as expeditiously as 

practicable, but in no event later than 5 

years after approval of the 

implementation plan revision.’’ In light 

of the considerable effort involved to 

retrofit SCR, we propose that five years 

is as expeditiously as practicable. 

Therefore, we propose a compliance 

deadline of five years from the date our 

final FIP becomes effective. 

4. Federal Monitoring, Recordkeeping, 

and Reporting 

We have explained earlier in section 

III.C.4 that the CAA and 40 CFR part 51, 

subpart K require that SIPs, including 

the regional haze SIP, contain certain 

elements sufficient to ensure emission 

limits are practically enforceable. EPA is 

proposing to disapprove Utah’s NOX

BART Alternative along with the 

associated monitoring, recordkeeping 

and reporting requirements in SIP 

sections IX.H.21 and H.22. EPA is 

proposing regulatory language as part of 

our FIP that specifies monitoring, 

recordkeeping, and reporting 

requirements for all BART 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. PM10 BART Determinations 

As discussed earlier in section IV.B.2, 

Utah determined that the PM10 BART 

emission limit for Hunter Units 1 and 2 

and Huntington Units 1 and 2 was 0.015 

lb/MMBtu based on a three-run test 

average. Utah noted that because the 

most stringent technology is in place at 

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230For example, Wyoming, Naughton Unit 3, Jim 

Bridger Units 1 through 4, Dave Johnston Units 3 

and 4, and Wyodak Unit 1. See 40 CFR 52.2636; 79 

FR 5220, (Jan. 30, 2014). 

231 40 CFR 51, appendix Y, section IV.D.1.9. 

232Utah Regional Haze State Implementation 

Plan: Emission Limits & Operating Practices, 

Sections IX.H.22.a.i.A–B, IX.H.22.b.i.A–B (2015). 

233 Id. 

234See 42 U.S.C. 7602(k); 40 CFR part 51, 

appendix Y, section V. 

235 40 CFR 51.212(c). 

236As necessary for our proposed approval, we 

propose to fill gaps in the 2015 Utah RH SIP 

submittals with the following already-approved 

sections from the 2011 Utah RH SIP: Section 

XX.B.8, Figures 1 and 2, Affected Class I Areas, pp. 

8–9; Section XX.D.6.b, Table 3, BART-Eligible 

Sources in Utah, p. 21; Section. XX.D.6.c, Sources 

Subject to BART, pp. 21–23. 

237 Id. 

238 58 FR 51735, 51738 (Oct. 4, 1993). 

239 44 U.S.C. 3501 et seq. 

these units and that the PM10 emission 

limits have been made enforceable in 

the SIP, no further analysis was 

required. 

EPA has reviewed Utah’s PM10 BART 

streamlined five-factor analysis and 

PM10 BART determinations for Hunter 

Units 1 and 2 and Huntington Units 1 

and 2 and proposes to find that these 

determinations meet the requirements of 

40 CFR 51.309(d)(4)(vii). The fabric 

filter baghouses installed at these BART 

units are considered the most stringent 

technology available. The emission limit 

of 0.015 lb/MMBtu at these units 

represents the most stringent emission 

limit for PM10 and is within the range 

of PM10 BART limits that EPA has 

approved in other states.230 Utah’s use 

of a streamlined approach to the fivefactor analysis is reasonable as the 

BART Guidelines provide that a 

comprehensive BART analysis can be 

avoided if a source commits to a BART 

determination that consists of the most 

stringent controls available.231

Utah’s regulatory text provides, 

‘‘[e]missions of particulate (PM) shall 

not exceed 0.015 lb/MMBtu heat input 

from each boiler based on a 3-run test 

average.’’ 232 It further states that 

‘‘[s]tack testing for the emission 

limitation shall be performed each year 

on each boiler.’’ 233 We note that BART 

limits must apply at all times.234

Furthermore, EPA’s credible evidence 

rule requires that a state’s plan must not 

preclude the use of any credible 

evidence or information, which can 

include evidence and information other 

than the test method specified in the 

plan, that would indicate whether a 

source was in compliance with 

applicable requirements.235

Consistent with these requirements, 

we propose to interpret Utah’s 

regulatory text as imposing a PM10 limit 

of 0.015 lb/MMBtu that applies at all 

times and does not preclude the use, 

including the exclusive use, of any 

credible evidence or information, 

relevant to whether a source is in 

compliance with the limit. 

F. Consultation With FLMs 

As discussed previously in section 

IV.G, Utah conducted FLM consultation 

during late 2014, providing over 60 days 

prior to the December 1, 2014 public 

hearing. Subsequently, the National 

Park Service provided extensive 

comments in response to a second 

public comment period in April 2015. 

Based on these considerations, we 

propose to find that Utah has met the 

requirements of 40 CFR 308(i)(2). 

VII. EPA’s Proposed Actions 

EPA is proceeding with co-proposals 

on Utah’s June 3, 2015 and October 20, 

2015 regional haze SIP revisions. Later 

on is a summary of our proposed 

actions. As noted above, EPA intends to 

finalize only one proposal, although it 

may differ from what is presented here 

based on any comments and additional 

information we receive. 

A. Proposed Approval 

We are proposing to approve the 

regional haze SIP revisions submitted by 

the State of Utah on June 3, 2015 and 

October 20, 2015: 

1. We are proposing to approve these 

aspects of the State’s June 4, 2015, 

which rely on elements from prior 

approvals 236: 

• NOX BART Alternative that 

includes NOX, and SO2, emission 

reductions from Hunter Units 1 through 

3, Huntington 1 and 2, and Carbon Units 

1 and 2, and PM10 emission reductions 

from Carbon Units 1 and 2. 

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2 

and Huntington Units 1 and 2. 

• Monitoring, recordkeeping and 

reporting requirements for units subject 

to the BART Alternative and the PM10

emission limits, including conditional 

approval of the recordkeeping 

requirements for the PM10 emission 

limits. 

2. We are proposing to approve these 

elements of the State’s October 20, 2015 

SIP submittal: 

• Enforceable commitments to revise, 

at a minimum, SIP Section XX.D.3.c and 

State rule R307–150 by March 2018 to 

clarify emission inventory requirements 

for tracking compliance with the SO2

milestone and properly accounting for 

the SO2 emission reductions due to the 

closure of the Carbon plant. 

B. Proposed Partial Disapproval/

Approval and Federal Implementation 

Plan 

1. We are proposing to approve these 

elements of the State’s SIP submittals, 

which rely on elements from prior 

approvals:237

• BART determinations and emission 

limits for PM10 at Hunter Units 1 and 2 

and Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements for units subject 

to the PM10 emission limits, including 

conditional approval of the 

recordkeeping requirements for the 

PM10 emission limits. 

2. We are proposing to disapprove 

these aspects of the State’s June 4, 2015 

SIP: 

• NOX BART Alternative that 

includes NOX, and SO2, emission 

reductions from Hunter Units 1 through 

3, Huntington 1 and 2, and Carbon Units 

1 and 2, and PM10 emission reductions 

from Carbon Units 1 and 2. 

• Monitoring, recordkeeping and 

reporting requirements for units subject 

to the BART Alternative. 

• The enforceable commitments to 

revise, at a minimum, SIP Section 

XX.D.3.c and State rule R307–150 by 

March 2018. 

3. We are proposing that if we finalize 

our co-proposal to disapprove the NOX

BART Alternative, we will promulgate a 

FIP to address the deficiencies in the 

Utah regional haze SIPs. The proposed 

FIP includes the following elements: 

• NOX BART determinations and 

limits for Hunter Units 1 and 2, 

Huntington Units 1 and 2. 

• Monitoring, recordkeeping, and 

reporting requirements applicable to 

Hunter Units 1 and 2, and Huntington 

Units 1 and 2. 

VIII. 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 238 and was 

therefore not submitted to the Office of 

Management and Budget (OMB) for 

review. This proposed rule applies to 

only two facilities containing four BART 

units. It is therefore not a rule of general 

applicability. 

B. Paperwork Reduction Act 

This proposed action does not impose 

an information collection burden under 

the provisions of the Paperwork 

Reduction Act (PRA).239 Because this 

proposed rule applies to just two 

facilities, the PRA does not apply. 

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240See, e.g., Mid-Tex Elec. Coop., Inc. v. FERC, 

773 F.2d 327 (D.C. Cir. 1985) (hereinafter Mid-Tex). 

241Adjusted to 2014 dollars, the UMRA threshold 

becomes $152 million. 242Andover Technology Partners, Cost of NOX

BART Controls on Utah EGUs, to EC/R, Inc. (Oct. 

22, 2015).Andover Technology Partners is a 

subcontractor to EC/R Incorporated. 

243 64 FR 43255, 43255–43257 (Aug. 10, 1999). 

244 64 FR 43255, 43257. 

245 Id. 

246 Id. 

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 this proposed rule on small entities, 

small entity is defined as: (1) A small 

business as defined by the Small 

Business Administration’s (SBA) 

regulations at 13 CFR 121.201; (2) a 

small governmental jurisdiction that is a 

government of a city, county, town, 

school district or special district with a 

population of less than 50,000; and (3) 

a small organization that is any not-forprofit enterprise which is independently 

owned and operated and is not 

dominant in its field. 

After considering the economic 

impacts of this proposed rule on small 

entities, I certify that this action will not 

have a significant economic impact on 

a substantial number of small entities 

under the RFA. This rule does not 

impose any requirements or create 

impacts on small entities as small 

entities are not subject to the 

requirements of this rule. Under the full 

approval approach in this proposed 

rule, EPA would approve all elements of 

the State’s submittals as meeting the 

federal regional haze requirements and 

therefore EPA’s action does not impose 

any requirements.240 Under the partial 

approval approach, EPA would 

disapprove the state’s SIP submittal and 

promulgate a FIP that consists of 

imposing federal controls to meet the 

BART requirement for emissions on four 

specific BART units at two facilities in 

Utah. The net result of this action is that 

EPA is proposing direct emission 

controls on selected units at only two 

sources, and those sources are large 

electric generating plants that are not 

owned by small entities, and therefore 

the owners are not a small entities 

under the RFA. 

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 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 

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 

actions 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 241 by State, local, or Tribal 

governments or the private sector in any 

one year. The private sector 

expenditures that would result from the 

approach to promulgate a FIP would 

include BART controls for all four units 

at the Hunter and Huntington plants 

would be $51.5 million 242 per year. 

Additionally, we do not foresee 

significant costs (if any) for state and 

local governments. Thus, because the 

annual expenditures associated with the 

approach to promulgate a FIP are less 

than the threshold of $100 million in 

any one year, this proposed rule is not 

subject to the requirements of sections 

202 or 205 of UMRA. This proposed 

rule is also not subject to the 

requirements of section 203 of UMRA 

because it contains no regulatory 

requirements that might significantly or 

uniquely affect small governments. 

E. Executive Order 13132: Federalism 

Executive Order 13132, 

Federalism,243 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.’’ 244

‘‘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.’’ 245 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 the State and local 

governments,’’ or EPA consults with 

state and local officials early in the 

process of developing the final 

regulation.246 EPA also may not issue a 

regulation that has federalism 

implications and that preempts state 

law unless the Agency consults with 

state and local officials early in the 

process of developing the final 

regulation. 

This action does not have federalism 

implications. Neither of the two 

approaches presented in this proposed 

rule will 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. 

Under the full approval approach, this 

proposed action would merely approve 

the state SIP as federally enforceable. 

Under the partial approval approach, 

this proposed action would merely 

address the State not fully meeting its 

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247 65 FR 67249, 67250 (Nov. 9, 2000). 248 59 FR 7629, 7629 (Feb. 16, 1994). 

obligation under the CAA to adequately 

address the visibility requirements of 

Part C of Title I of the CAA in its SIP 

and to prohibit emissions from 

interfering with other states measures to 

protect visibility. Thus, Executive Order 

13132 does not apply to this action. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

Executive Order 13175, entitled 

‘‘Consultation and Coordination with 

Indian Tribal Governments’’, 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.’’ 247 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 

This action is not subject to Executive 

Order 13045 (62 FR 19885, April 23, 

1997) because the environmental health 

or safety risks addressed by this action 

do not present a disproportionate risk to 

children. Note, however, that emissions 

reductions achieved as a result of this 

rule, under either proposal, will have a 

positive benefit on children’s health, as 

they are especially vulnerable to 

impacts from emissions. 

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 of the National Technology 

Transfer and Advancement Act 

(NTTAA) of 1995 requires Federal 

agencies to evaluate existing technical 

standards when developing a new 

regulation. Section 12(d) of NTTAA, 

Public Law 104–113, 12(d) (15 U.S.C. 

272 note) directs EPA to consider and 

use ‘‘voluntary consensus standards’’ in 

its regulatory activities unless to do so 

would be inconsistent with applicable 

law or otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., materials specifications, 

test methods, sampling procedures, and 

business practices) that are developed or 

adopted by voluntary consensus 

standards bodies. NTTAA directs 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, establishes 

federal executive policy on 

environmental justice.248 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. 

I certify that the approaches under 

this proposed rule will not have 

potential disproportionately high and 

adverse human health or environmental 

effects on minority, low-income or 

indigenous/tribal populations. The 

results of this evaluation are available in 

the docket. Both approaches would 

result in overall emission reductions for 

NOX, SO2 and PM10 and therefore an 

increase in the level of environmental 

protection for all affected populations. 

EPA, however, will consider any input 

received during the public comment 

period regarding environmental justice 

considerations. 

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

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Nitrogen dioxide, Particulate matter, 

Sulfur oxides. 

Dated: December 16, 2015. 

Shaun L. McGrath, 

Regional Administrator, Region 8. 

For the reasons discussed in the 

preamble, the Environmental Protection 

Agency proposes to amend 40 CFR part 

52 as follows: 

PART 52—APPROVAL AND 

PROMULGATION OF 

IMPLEMENTATION PLANS 

■ 1. The authority citation for part 52 

continues to read as follows: 

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

Subpart TT—Utah 

■ 2. Add § 52.2336 to read as follows: 

§ 52.2336 Federal implementation plan for 

regional haze. 

(a) Applicability. (1) This section 

applies to each owner and operator of 

the following emissions units in the 

State of Utah: 

(i) PacifiCorp Hunter Plant Units 1 

and 2; and 

(ii) PacifiCorp Huntington Plant Units 

1 and 2. 

(b) Definitions. Terms not defined 

here 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 of this section. 

(3) 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. 

(4) FIP means Federal Implementation 

Plan. 

(5) The term lb/MMBtu means pounds 

per million British thermal units of heat 

input to the fuel-burning unit. 

(6) NOX means nitrogen oxides. 

(7) 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 unit. It is not necessary for fuel 

to be combusted for the entire 24-hour 

period. 

(8) The owner/operator means any 

person who owns or who operates, 

controls, or supervises a unit identified 

in paragraph (a) of this section. 

(9) 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, NOX in excess of 

the following limitations: 

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2052 Federal Register / Vol. 81, No. 9 / Thursday, January 14, 2016 / Proposed Rules 

TABLE 1—TO § 52.2336—EMISSION

LIMITS FOR BART UNITS

Source name/BART unit 

NOX emission 

limit—lb/

MMBtu 

(30-day rolling 

average) 

PacifiCorp Hunter Plant/Unit 

1 1 ...................................... 0.07 

PacifiCorp Hunter Plant/Unit 

2 1 ...................................... 0.07 

PacifiCorp Huntington Plant/

Unit 1 1 .............................. 0.07 

PacifiCorp Huntington Plant/

Unit 2 1 .............................. 0.07 

1The owners and operators of PacifiCorp 

Hunter Units 1 and 2 and Huntington Units 1 

and 2, shall comply with the NOX emission 

limit for BART of 0.07 lb/MMBtu and other requirements of this section by [date five years 

from the effective date of the final rule]. 

(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 Hunter 

Units 1 and 2 shall comply with the 

NOX emission limit of 0.07 lb/MMBtu 

and other requirements of this section 

by [date five years from the effective 

date of the final rule]. The owners and 

operators of PacifiCorp Huntington 

Units 1 and 2 shall comply with the 

NOX emission limit of 0.07 lb/MMBtu 

and other requirements of this section 

by [date five years from the effective 

date of the final rule]. 

(e) Compliance determinations for 

NOX. (1) For all BART units: 

(i) CEMS. At all times after the earliest 

compliance date specified in paragraph 

(d) of this section, the owner/operator of 

each unit shall maintain, calibrate, and 

operate a CEMS, in full compliance with 

the requirements found at 40 CFR part 

75, to accurately measure 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

emission rate in lb/MMBtu at the CEMS 

in accordance with the requirements of 

40 CFR part 75. At the end of each 

operating day, the owner/operator shall 

calculate and record a new 30-day 

rolling average emission rate in lb/

MMBtu from the arithmetic average of 

all valid hourly emission rates from the 

CEMS for the current operating day and 

the previous 29 successive operating 

days. 

(B) An hourly average NOX emission 

rate in lb/MMBtu is valid only if the 

minimum number of data points, as 

specified in 40 CFR part 75, is acquired 

by both the pollutant concentration 

monitor (NOX) and the diluent monitor 

(O2 or CO2). 

(C) 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. 

(f) 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. 

(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. 

(g) 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 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. 

(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. 

(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 paragraphs (g)(1) and (2) of 

this section. 

(h) Notifications. (1) The owner/

operator shall promptly 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 

promptly submit semi-annual progress 

reports on construction of any such 

equipment. 

(3) The owner/operator shall 

promptly submit notification of initial 

startup of any such equipment. 

(i) 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. 

(j) 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. 

[FR Doc. 2015–33108 Filed 1–13–16; 8:45 am] 

BILLING CODE 6560–50–P 

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