Vol. 79 Friday, 

No. 153 August 8, 2014 

Part II 

Environmental Protection Agency 

40 CFR Part 49 

Approval of Air Quality Implementation Plans; Navajo Nation; Regional 

Haze Requirements for Navajo Generating Station; Final Rule 

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46514 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

1For more detail and for citations or references 

to the information provided in this Background 

section, please see the Proposed Rule at 78 FR 8274 

(February 5, 2013). 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 49 

[EPA–R09–OAR–2013–0009; FRL–9914–62– 

Region 9] 

Approval of Air Quality Implementation 

Plans; Navajo Nation; Regional Haze 

Requirements for Navajo Generating 

Station 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is promulgating a sourcespecific Federal Implementation Plan 

(FIP) requiring the Navajo Generating 

Station (NGS), a coal-fired power plant 

located on the Navajo Nation near Page, 

Arizona, to achieve reductions in oxides 

of nitrogen (NOX) required under the 

Best Available Retrofit Technology 

(BART) provisions of the Clean Air Act 

(CAA) and the Regional Haze Rule 

(RHR). On February 5, 2013, EPA issued 

a proposed BART determination for 

NGS and an alternative to BART. In a 

supplemental proposal on October 22, 

2013, EPA proposed to approve a new 

alternative plan, based on an agreement 

developed by a group of stakeholders 

known as the Technical Work Group 

(TWG). EPA is finalizing the alternative 

to BART described in our supplemental 

proposal. This rule is consistent with 

the TWG Agreement, including a 

lifetime cap in total emissions of NOX

from NGS over 2009–2044 (2009–2044 

NOX Cap). Our final action will achieve 

greater emissions reductions than BART 

and is expected to significantly reduce 

the impact of NGS on visibility at 11 

mandatory Class I Federal areas. The 

operator of NGS must implement one of 

several alternative operating scenarios 

to achieve the necessary emission 

reductions to comply with the 2009– 

2044 NOX Cap. 

DATES: Effective date: This rule is 

effective on October 7, 2014. 

FOR FURTHER INFORMATION CONTACT: 

Anita Lee, EPA Region 9, (415) 972– 

3958, lee.anita@epa.gov. 

SUPPLEMENTARY INFORMATION: EPA has 

established a docket for this action 

under Docket ID No. EPA–R09–OAR– 

2013–0009. The index to the docket for 

this action is available electronically at 

http://www.regulations.gov and in hard 

copy at EPA Region 9, 75 Hawthorne 

Street, San Francisco, California. While 

documents in the docket are listed in 

the index, some information may be 

publicly available only at the hard copy 

location (e.g. copyrighted material, 

voluminous or oversized documents, 

etc.), and some may not be publicly 

available in either location (e.g. 

Confidential Business Information 

(CBI)). To inspect the hard copy 

materials, please schedule an 

appointment during normal business 

hours with the contact listed in the FOR

FURTHER INFORMATION CONTACT section. 

A reasonable fee may be charged for 

copies. 

Throughout this document, ‘‘we’’, 

‘‘us’’, and ‘‘our’’ refer to EPA. 

Table of Contents 

I. Executive Summary 

II. Background for the Final Rule 

A. History of NGS 

B. Summary of Statutory and Regulatory 

Framework for Addressing Visibility and 

Sources Located in Indian Country 

C. Summary of Proposed Rule and 

Supplemental Proposal 

D. Summary of Legal Rationale for 

Compliance Flexibility 

III. Summary of Final FIP Provisions 

IV. Summary of Major Issues Raised by 

Commenters 

V. Summary of Final Action 

VI. Administrative Requirements 

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 

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 

K. Congressional Review Act 

L. Petitions for Judicial Review 

I. Executive Summary 

EPA is taking final action pursuant to 

the CAA and the RHR to require Units 

1, 2, and 3 at NGS to reduce emissions 

of NOX in order to reduce the impact 

NGS has on visibility at 11 mandatory 

Class I Federal areas. We are finalizing 

an alternative to BART based on agreedupon recommendations developed by a 

group of diverse stakeholders known as 

the Technical Work Group (TWG). Our 

final action limits emissions of NOX

from NGS by establishing a long-term 

facility-wide cap on total NOX

emissions from 2009 to 2044 and 

requires the implementation of one of 

several alternative operating scenarios 

to ensure that the 2009–2044 cap is met. 

Generally, the alternative operating 

scenarios require the closure of one unit 

at NGS (or the curtailment of electricity 

generation by a similar amount) in 2019, 

and compliance with a NOX emission 

limit that is achievable with the 

installation of selective catalytic 

reduction (SCR) on two units in 2030. 

As part of our final action, EPA is also 

setting a source-specific BART 

Benchmark against which to compare 

the TWG Alternative to ensure that it 

will achieve greater reasonable progress 

than BART. The BART Benchmark is 

consistent with the BART determination 

we proposed on February 5, 2013, 

requiring all three units at NGS to meet 

an emission limit achievable with SCR 

within five years of a final rule. EPA is 

not finalizing our proposed BART 

determination for NGS in the regulatory 

requirements of this Final Rule. 

EPA’s action to finalize an alternative 

to BART consistent with the TWG 

Agreement will achieve greater NOX

emission reductions at lower cost than 

BART in exchange for flexibility in the 

timeframe for achieving NOX

reductions. When fully implemented, 

this Final Rule requires over an 80 

percent reduction in NOX emissions 

from NGS and is expected to 

significantly reduce the impact of NGS 

on visibility at 11 mandatory Class I 

Federal areas. 

II. Background for the Final Rule 

A. History of NGS 

NGS is a coal-fired power plant 

located on the Navajo Nation Indian 

Reservation near Page, Arizona. The 

facility consists of three 750 megawatt 

(MW) coal-fired electric utility steam 

generating units with a total capacity of 

2250 MW constructed from 1974 to 

1976. The three units at NGS are coowned by six entities: The United States 

Bureau of Reclamation (Reclamation) 

(24.3 percent); Salt River Project (21.7 

percent), which also serves as the 

facility operator; Los Angeles 

Department of Water and Power (21.2 

percent); Arizona Public Service (14 

percent); NV Energy (11.3 percent); and 

Tucson Electric Power (7.5 percent). 

Federal participation in NGS was 

authorized in the Colorado River Basin 

Project Act of 1968 as a preferred 

alternative to building hydroelectric 

dams in the Grand Canyon for the 

purpose of providing power to the 

Central Arizona Project (CAP).1 The 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46515 

2See document title ‘‘2013_0104 Joint Federal 

Agency Statement on NGS’’ within document 

number 0005 in the docket for this proposed 

rulemaking at EPA–R09–OAR–2013–0009, which 

can be found at www.regulations.gov. 

3See 78 FR 8274 (February 5, 2013) and 78 FR 

62509 (October 22, 2013). 

4See 42 U.S.C. 7419A(a)(1). 

5See 64 FR 35765 (April 22, 1999). 

6See 40 CFR 51.308(e)(1). 

7See 74 FR 44314 (August 28, 2009); 78 FR 8279 

(February 5, 2013); see also 56 FR 50172 (October 

3, 1991) addressing BART for SO2 based on 

Reasonably Attributable Visibility Impairment. 

8See 70 FR 39104 at 39161 (July 6, 2005). 

9 Id. 

10 42 U.S.C. 7491(g)(2) and 40 CFR 

51.308(e)(1)(A)(ii)(A). 11 40 CFR 51.308(e)(1)(ii)(A). 

12See 40 CFR part 49; see also 59 FR 43956 

(August 25, 1994) (proposed rule); 63 FR 7254 

(February 12, 1998) (final rule); Arizona Public 

Service Company v. EPA, 211 F.3d 1280 (D.C. Cir. 

2000), cert. den., 532 U.S. 970 (2001) (upholding 

the TAR). 

13See 40 CFR 49.11(a). 

14See 56 FR 50172 (October 3, 1991). In 1999, 

EPA proposed a FIP for NGS to fill the regulatory 

gap that existed because Arizona State permits and 

SIP rules are not applicable or enforceable in the 

Navajo Nation, and the Tribe had not sought 

approval of a TIP covering the plant. 64 FR 48731 

(September 8, 1999). EPA then re-proposed the FIP 

with some additional conditions in September 

2006. 71 FR 53631 (September 12, 2006). EPA 

finalized that NGS FIP on March 5, 2010. 75 FR 

10174. 

CAP is a 336-mile water distribution 

system that delivers about 1.5 million 

acre-feet (AF) per year of Colorado River 

water from Lake Havasu in western 

Arizona to non-Indian agricultural (NIA) 

water users in central Arizona, Indian 

tribes located in Arizona, and municipal 

water users in Maricopa, Pinal, and 

Pima Counties in Arizona. The CAP 

water is used to meet the terms of a 

number of Indian water-rights 

settlements in central Arizona and to 

reduce groundwater usage in the region. 

A portion of Reclamation’s share of 

electricity from NGS powers the pumps 

that move CAP water to its destinations 

along the distribution system. 

Several tribes located in Arizona, 

including the Gila River Indian 

Community, the Ak-Chin Indian 

Community, the Tohono O’odham 

Nation, the San Carlos Apache Tribe, 

the White Mountain Apache Indian 

Tribe, the Fort McDowell Yavapai 

Nation, the Salt River Pima-Maricopa 

Indian Community, the Navajo Nation, 

the Yavapai-Apache Nation, the Hopi 

Tribe, the Pascua Yaqui Tribe, the 

Yavapai-Prescott Tribe, and the Tonto 

Apache Nation, have CAP water 

allocations or contracts. In exchange for 

allocations of CAP water at reduced cost 

and access to funds for the development 

of water infrastructure, the tribes with 

water settlement agreements have 

released their claims to other water in 

Arizona. Excess NGS power owned by 

Reclamation that is not used by CAP is 

sold and profits are deposited into the 

Lower Colorado River Basin 

Development Fund (Development Fund) 

to support the tribal water settlement 

agreements. The U.S. Department of the 

Interior (DOI or Interior), through 

Reclamation, plays an important role in 

the implementation of these settlement 

agreements and the management of the 

Development Fund. 

The coal used by NGS is supplied by 

the Kayenta Mine, operated by Peabody 

Energy and located on reservation lands 

of both the Navajo Nation and the Hopi 

Tribe. Taxes and royalties from NGS 

and the Kayenta Mine are paid to the 

Navajo Nation and Hopi Tribe, 

contributing to the annual revenues for 

both governments. EPA understands 

that the process is underway to renew 

site leases for NGS and the Kayenta 

Mine, as well as associated rights of way 

agreements and contracts with the 

Navajo Nation and Hopi Tribe. 

Given the extent of federal and tribal 

interests in NGS, on January 4, 2013, 

EPA, DOI, and the Department of Energy 

(DOE) signed a joint federal agency 

statement (Joint Statement) committing 

to collaborate on several short- and 

long-term goals, including analyzing 

and pursuing strategies for providing 

clean, affordable, and reliable power, 

affordable and sustainable water, and 

sustainable economic development to 

key stakeholders who currently depend 

on NGS.2 The Joint Statement also 

recognizes the trust responsibility of the 

Federal government to Indian tribes. 

B. Summary of Statutory and Regulatory 

Framework for Addressing Visibility and 

Sources Located in Indian Country 

In our Proposed Rules, we provided a 

detailed discussion of the statutory and 

regulatory framework for addressing 

visibility impairment in the mandatory 

Class I Federal Areas, addressing 

sources located in Indian country under 

the statute and the Tribal Authority 

Rule (TAR), and developing BART 

determinations pursuant to the CAA 

and the BART Guidelines set forth in 

Appendix Y to 40 CFR Part 51.3 Here, 

we provide a brief summary of the 

statutory and regulatory framework. 

Title I, part C, subpart II of the CAA 

Amendments of 1977 establishes a 

visibility protection program that sets 

forth ‘‘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 man-made air 

pollution.’’ 4 EPA promulgated regional 

haze regulations implementing the 

program on April 22, 1999.5 Consistent 

with the statutory requirement in 42 

U.S.C. 7491(b)(2)(a), EPA’s 1999 

regional haze regulations include a 

provision that States must require 

certain major stationary sources to 

procure, install, and operate BART. This 

provision covers sources in listed 

industrial categories with the potential 

to emit 250 or more tons per year of an 

air pollutant that were ‘‘in existence on 

August 7, 1977, but which ha[ve] not 

been in operation for more than fifteen 

years as of such date.’’ These sources are 

considered to be ‘‘BART-eligible.’’ 6

NGS meets these criteria and is a BARTeligible source.7

BART-eligible sources that are 

reasonably anticipated to cause or 

contribute to visibility impairment are 

‘‘subject’’ to the BART requirements.8

Generally speaking, a BART-eligible 

source with a predicted visibility impact 

of 0.5 deciviews (dv) or more in a Class 

I area is considered to ‘‘contribute’’ to 

visibility impairment.9 NGS contributes 

to visibility impairment at 11 

surrounding Class I areas in excess of 

this threshold, and is thus subject to 

BART. 

In determining BART, States are 

required to take into account five factors 

identified in the CAA and EPA’s 

regulations.10 Those factors are: (1) The 

costs of compliance, (2) the energy and 

non-air quality environmental impacts 

of compliance, (3) any pollution control 

equipment in use or in existence 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.11 EPA’s 

guidelines for evaluating BART provide 

more detail and are set forth in 

Appendix Y to 40 CFR Part 51. 

In 1998, EPA promulgated the Tribal 

Authority Rule (TAR) relating to 

implementation of CAA programs in 

Indian country.12 In the TAR, EPA 

determined that it has the discretionary 

authority to promulgate ‘‘such federal 

implementation plan provisions as are 

necessary or appropriate to protect air 

quality’’ consistent with CAA sections 

301(a) and 301(d)(4) when a tribe has 

not submitted or EPA has not approved 

a Tribal Implementation Plan (TIP).13

EPA has previously promulgated FIPs 

under the TAR to regulate air pollutants 

emitted from NGS.14

Under the CAA, compliance with 

emission limits determined to be BART 

must be achieved as expeditiously as 

practicable but not later than 5 years 

after the effective date of the final BART 

determination (See CAA 169A(b)(2)(A) 

and (g)(4)). As discussed in greater 

detail in our Proposed Rule, EPA 

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15Because of its complicated history and its 

location on the Navajo Nation, NGS faces numerous 

unique complexities and the unusual requirement 

to comply with NEPA for lease and other rights-ofway approvals, which apply only to NGS and Four 

Corners Power Plant, the other coal-fired power 

plant located on the Navajo Nation. EPA also 

understands the importance of the continued 

operation of NGS and the Kayenta Mine to the 

Navajo Nation and Hopi Tribe as a source of direct 

revenues through lease payments and coal royalties, 

as well as the importance of Reclamation’s share of 

NGS to supply water to many tribes located in 

Arizona in accordance with several water 

settlement acts. EPA also recognizes that 

Reclamation may have fewer options compared to 

the other owners for financing pollution control or 

other large capital improvement projects at NGS. 

SRP expressed concern that the owners of NGS may 

choose to retire the facility if faced with the 

financial risk of making a large capital investment 

within 5 years without also having certainty that 

the lease and contract re-negotiations would 

conclude in a timely and favorable manner. 

16 40 CFR 51.308(e)(2). 

17 40 CFR 51.308(e)(3). 

18 40 CFR 51.308(e)(2)(iii). 

19See 74 FR 44314 (August 28, 2009). 

20See 78 FR 8274 (February 5, 2013). 

21 Id. at 8288. 

22 Id. at 8284. 

23 Id. at 8289. 

24 Id. at 8290–92. 

25 78 FR 62509 at 62511 (October 22, 2013). 26 78 FR 8274 at 8291 (February 5, 2013). 

recognizes that the circumstances 

related to NGS create unusual and 

significant challenges for a 5-year 

compliance schedule.15 Based on those 

challenges and our discretion under the 

TAR for implementing CAA 

requirements in Indian country, we 

considered other options that are 

consistent with the CAA and RHR, and 

that provide for a more flexible, 

extended compliance schedule. 

EPA’s BART regulations allow an 

alternative in lieu of BART, provided 

the alternative results in greater 

reasonable progress than would have 

been achieved through installation of 

BART.16 Generally, an alternative is 

considered to be approvable provided it 

results in greater emissions reductions 

and the geographic distribution in 

emissions from the alternative is not 

substantially different than the 

distribution of the emissions under 

BART.17 For a state that is subject to the 

submittal deadlines in the RHR, the 

regulations provide that alternatives to 

BART must ensure that all necessary 

emission reductions occur within the 

period of the first long-term strategy for 

regional haze (i.e., by 2018) for states 

that were required to submit regional 

haze SIPs in December 2007.18 Thus, if 

states had submitted timely regional 

haze SIPs in 2007 with BART 

compliance deadlines in 2012, the RHR 

provided more than 5 additional years 

for the implementation of alternatives to 

BART. 

C. Summary of Proposed Rule and 

Supplemental Proposal 

EPA published an advanced notice of 

proposed rulemaking (ANPR) 

concerning BART for NGS and the Four 

Corners Power Plant in August 2009.19

On February 5, 2013, EPA’s proposed 

BART determination for NGS was 

published in the Federal Register and 

provided a thorough discussion of the 

statutory and regulatory framework for 

addressing visibility through 

application of BART for sources located 

in Indian country, and of the factual 

background for our BART determination 

at NGS.20 The proposal analyzed the 

five BART factors and proposed to find 

that BART for NGS was installation of 

emissions controls to meet a NOX

emission limit of 0.055 lb/MMBtu based 

on a rolling average of 30 boiler 

operating days (30–BOD average).21

However, in recognition of the 

important role that NGS and the 

Kayenta Mine play in providing 

employment and revenue to the Navajo 

Nation and Hopi Tribe, and the role of 

Reclamation’s share of electricity 

generated by NGS in fulfilling water 

settlement agreements with numerous 

tribes located in Arizona, we proposed 

that the potential economic impacts to 

tribes argue for thoughtful consideration 

of how flexibility in the compliance 

timeframe could be provided consistent 

with the air quality goals of the CAA.22

Therefore, as discussed in our Proposed 

Rule, EPA proposed to exercise our 

authority and discretion under section 

301(d)(4) of the CAA and 40 CFR 

49.11(a) to propose an appropriate 

timeframe for alternative measures to 

BART under the RHR for NGS. We 

provided a thorough discussion of the 

legal rationale for setting the 

compliance schedule for alternative 

measures in our Proposed Rule.23

Our Proposed Rule included a 

framework for evaluating alternatives to 

BART.24 As part of the framework, EPA 

proposed a NOX emission credit for the 

previous early and voluntary 

installation of low-NOX burners with 

separated over-fire air (LNB/SOFA) over 

the 2009–2011 timeframe (LNB/SOFA 

credit). We proposed that the LNB/

SOFA credit supported setting a 

compliance timeframe based on the 

flexibility under section 301(d)(4) of the 

CAA and 40 CFR 49.11(a).25 EPA 

proposed to find that an alternative is 

‘‘better than BART’’ if the total 

emissions over 2009–2044 from the 

alternative measure, minus the LNB/

SOFA credit, are less than the total 

emissions under our proposed BART 

determination for the same period (i.e., 

the BART Benchmark). Consistent with 

this framework, EPA proposed an 

alternative to BART, requiring 

compliance with an emission limit of 

0.055 lb/MMBtu on one unit per year in 

2021, 2022, and 2023 (Alternative 1). 

We calculated that total emissions 

under Alternative 1 over 2009–2044, 

minus the LNB/SOFA credit, would be 

less than emissions based on the BART 

Benchmark. Thus, we proposed to find 

that Alternative 1 was ‘‘better than 

BART’’. EPA recognized that there may 

be interest in additional flexibility 

beyond the 2021–2023 timeframe. EPA 

evaluated two additional compliance 

schedules but did not propose to 

approve them as ‘‘better than BART’’ 

alternatives because total emissions over 

2009–2044 under these compliance 

schedules exceeded the BART 

Benchmark. However, we noted that 

potential technologies or other options 

for achieving additional emission 

reductions could bridge the NOX

emission reduction deficit for 

alternatives to BART with compliance 

schedules that do not, by themselves, 

meet the BART Benchmark.26 We 

invited stakeholders to submit 

additional BART alternatives, consistent 

with our proposed framework, for EPA’s 

consideration. 

On July 26, 2013, a stakeholder group, 

known as the Technical Work Group on 

NGS (TWG), submitted an agreement 

that had been established among the 

seven diverse entities in the TWG. We 

refer to the July 26, 2013, document as 

the ‘‘TWG Agreement.’’ The TWG is 

composed of representatives from 

Central Arizona Water Conservation 

District (CAWCD), the Environmental 

Defense Fund (EDF), the Gila River 

Indian Community (Gila River or the 

Community), the Navajo Nation 

(Navajo), Salt River Project (SRP) on 

behalf of itself and the other non-federal 

owners, DOI, and Western Resource 

Advocates (WRA). Although EPA 

attended the opening session of a ‘‘kickoff’’ meeting for the TWG on March 21, 

2013, at which we described our 

Proposed Rule, EPA did not otherwise 

participate in the TWG and was not 

involved in any of the discussions 

leading to submittal of the TWG 

Agreement. 

Appendix B to the TWG Agreement 

contained TWG’s recommendation for 

an alternative to BART. In general, the 

alternative plan in the TWG Agreement 

included closure of one unit at NGS, or 

curtailment of net generating capacity 

by an equivalent amount, in 2019 and 

compliance with a NOX emission limit 

of 0.07 lb/MMBtu on two units at NGS 

beginning in 2030. The TWG Agreement 

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27See 78 FR 62509 (October 22, 2013). 

28 Id. Tables 1 and 3 at 62515–62516. 

29 Id. Table 2 and footnote 32 at 62515. 

30 In contrast, in our Proposed Rule, we 

calculated the BART Benchmark and emissions 

under BART alternatives using the actual early 

installation dates for LNB/SOFA and then applied 

the LNB/SOFA credit to BART alternatives for 

comparison against the BART Benchmark. 

Although this method would have resulted in a 

lower numerical value for the 2009–2044 NOX Cap, 

the LNB/SOFA credit (representing the early 

emission reductions achieved over 2009–2018) 

would have instead been subtracted from the 

calculations of cumulative emissions under the 

BART alternative. Although this is functionally 

equivalent to the method used in the Supplemental 

Proposal, this method would make annual 

comparisons of actual cumulative emissions under 

the BART alternative against the BART Benchmark 

more complicated because it would have required 

adjustments every year to total emissions to subtract 

out the LNB/SOFA credit. By accounting for the 

LNB/SOFA credit in the BART Benchmark, the 

actual annual emissions from NGS can be directly 

compared to the BART Benchmark without any 

further adjustments. 

also included a provision requiring the 

operator of NGS to cease conventional 

coal-fired generation at NGS by the end 

of 2044. 

EPA independently evaluated 

Appendix B to the TWG Agreement to 

determine whether it complied with the 

framework we put forth in our Proposed 

Rule, as well as the statutory and 

regulatory requirements in the CAA and 

the RHR. On October 22, 2013, EPA 

published a Supplemental Proposal 

describing the TWG Agreement and 

requesting comment.27 Our 

Supplemental Proposal contained a 

detailed evaluation of Appendix B to 

the TWG Agreement along with a 

discussion of our legal rationale for 

proposing to approve requirements 

consistent with the TWG Agreement as 

meeting the requirements for an 

alternative to BART. Throughout this 

document, we refer to the regulations 

we proposed in our Supplemental 

Proposal that are consistent with 

Appendix B of the TWG Agreement as 

the ‘‘TWG Alternative.’’ Thus, in this 

document, the term TWG Alternative 

refers to EPA’s independent regulatory 

requirements for NGS consistent with 

the TWG Agreement, rather than to 

Appendix B of the TWG Agreement. 

In our Supplemental Proposal, we 

proposed to revise the numerical value 

of the BART Benchmark from our 

Proposed Rule. We also proposed a 

2009–2044 NOX Cap based on the 

revised numerical value of the BART 

Benchmark. In our Proposed Rule, we 

calculated the BART Benchmark to be 

358,974 tons of NOX. As discussed in 

our Supplemental Proposal, we 

proposed three changes to the BART 

Benchmark: (1) Correction of a 

transcription error; (2) correction of the 

date that EPA anticipated would be 5 

years following the effective date of the 

final rule (i.e., July 1, 2019 instead of 

January 1, 2018); and (3) application of 

the LNB/SOFA credit to the BART 

Benchmark, rather than alternatives to 

BART, to represent emissions under 

BART if LNB/SOFA had been installed 

concurrently with selective catalytic 

reduction (SCR) to reduce NOX

emissions.28 Based on these changes, 

EPA proposed a 2009–2044 NOX Cap of 

494,899 tons. Although EPA revised our 

accounting method for the LNB/SOFA 

credit in our Supplemental Proposal, 

EPA provided a demonstration that the 

method EPA used in our Proposed Rule 

to compare our proposed BART 

determination against BART alternatives 

was equivalent to the method in the 

Supplemental Proposal.29 The 

application of the LNB/SOFA credit to 

the BART Benchmark in the 

Supplemental Proposal represented 

what total emissions over 2009–2044 

would have been under our proposed 

BART determination if the operator of 

NGS had elected to install LNB/SOFA 

concurrently with SCR, i.e., within 5 

years of a final rule, rather than in 

2009–2011. Calculation of the BART 

Benchmark and 2009–2044 NOX Cap in 

this manner is easier to apply and 

enforce in the context of a cap in NOX

emissions because the LNB/SOFA credit 

is built into the BART Benchmark rather 

than subtracted each year from actual 

cumulative emissions.30

In addition to the enforceable 2009– 

2044 NOX Cap, our Supplemental 

Proposal defines the operating scenarios 

that would be required depending on 

the final outcome of NGS ownership 

after the expiration of the current lease 

term at the end of 2019. In the TWG 

Agreement, the owners of NGS 

committed to maintain emissions from 

NGS below the 2009–2044 NOX Cap 

regardless of post-2019 ownership of 

NGS and the applicable operating 

scenario. As a result, the operating 

scenarios in the TWG Alternative 

include specific actions for achieving 

emission reductions in 2019 and in 

2030. The TWG Alternative also 

provides for an operating scenario that 

is less well-defined in terms of specific 

actions but establishes a second NOX

emissions cap over the period of 2009– 

2029 (2009–2029 NOX Cap) that is 

equivalent to emission reductions that 

would be achieved by a more welldefined operating scenario. The 2009– 

2029 NOX Cap would apply in addition 

to the 2009–2044 NOX Cap. The 

Supplemental Proposal included 

requirements for annual emission 

reporting to EPA that would also be 

made publicly available as part of the 

compliance demonstration for the TWG 

Alternative. 

D. Summary of Legal Rationale for 

Compliance Flexibility 

In our February 5, 2013, proposal for 

NGS, EPA proposed an alternative to 

BART that we referred to as 

Alternative 1. EPA proposed to find that 

consideration of a compliance schedule 

beyond 2018 for Alternative 1 at NGS 

was appropriate for a number of 

reasons, including the importance of 

NGS to numerous Indian tribes located 

in Arizona and the federal government’s 

reliance on NGS to meet the 

requirements of water settlements with 

several tribes. Providing this timeframe 

for compliance would not, in itself, 

avoid or mitigate increases in water 

rates for tribes located in Arizona; 

however, it would provide time for the 

collaborating federal agencies to explore 

options to avoid or minimize potential 

impacts to tribes, including seeking 

funding to cover expenses for the 

federal portion of pollution control at 

NGS. 

In developing this framework, EPA 

proposed to exercise its authority and 

discretion under section 301(d)(4) of the 

CAA, 42 U.S.C. 7601(d)(4) and the TAR, 

40 CFR 49.11(a), and proposed an 

appropriate timeframe for an alternative 

measure under the RHR for NGS. EPA 

considered this timeframe to be 

consistent with the general 

programmatic requirements. Under the 

RHR, States and regulated sources had 

almost 20 years from the issuance of the 

rule in 1999 to design and implement 

alternative measures to BART. For 

numerous reasons, including the myriad 

stakeholder interests and complex 

governmental interests unique to NGS, 

we are only now addressing the BART 

requirements for NGS. 

Our proposal to require emission 

reductions beyond 2018 was supported 

by CAA section 301(d)(4) and the TAR 

codified at 40 CFR 49.11(a). The TAR 

reflects EPA’s commitment to 

promulgate ‘‘such Federal 

implementation plan provisions as are 

necessary or appropriate to protect air 

quality’’ in Indian country where a tribe 

either does not submit a Tribal 

Implementation Plan (TIP) or does not 

receive approval of a submitted TIP 

(emphasis added). 

The use of the term ‘‘provisions as are 

necessary or appropriate’’ indicates 

EPA’s determination that it may only be 

necessary or appropriate to promulgate 

a FIP of limited scope. The United 

States Court of Appeals for the Tenth 

Circuit has previously endorsed the 

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46518 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

31See Ariz. Public Serv. Co. v. EPA, 562 F.3d 

1116 (10th Cir. 2009). 

32 Id. 

33The combination of the 2009–2044 and 2009– 

2029 NOX Caps under TWG Alternative B means 

that if NGS exceeds the 2009–2029 NOX Cap prior 

to 2029 it must cease operation, but the operator 

may re-start operation after 2030 as long as 

cumulative emissions have not yet exceeded the 

2009–2044 NOX Cap. 

application of this approach in a 

challenge to the FIP for the Four Corners 

Power Plant, stating: ‘‘[40 CFR 49.11(a)] 

provides the EPA discretion to 

determine what rulemaking is necessary 

or appropriate to protect air quality and 

requires the EPA to promulgate such 

rulemaking.’’ 31 The court went on to 

observe: ‘‘Nothing in section 49.11(a) 

requires EPA . . . to submit a plan 

meeting the completeness criteria of [40 

CFR part 51] Appendix V.’’ 32 While the 

decision in the Tenth Circuit focused on 

40 CFR part 51, Appendix V, EPA 

believes the same considerations apply 

to the promulgation of a FIP intended to 

address the objectives set forth in 40 

CFR 51.308(e)(2). In particular, EPA has 

discretion to determine if and when a 

FIP addressing the objectives set forth in 

40 CFR 51.308(e)(2) should be 

promulgated, which necessarily 

includes discretion to determine the 

timing for complying with the 

requirements of any such FIP. 

III. Summary of Final FIP Provisions 

EPA is finalizing our finding that it is 

necessary or appropriate to promulgate 

a source-specific FIP requiring NGS to 

achieve NOX emission reductions 

required by the BART provisions of the 

CAA and RHR. EPA is determining that 

our proposed NOX emission limit of 

0.055 lb/MMBtu, based on our analysis 

of the relevant factors, establishes the 

appropriate BART Benchmark for 

determining ‘‘better than BART.’’ 

Further, we are finalizing our 

assessment that the TWG Alternative, 

which establishes an enforceable 2009– 

2044 cap on NOX emissions from NGS 

over the life of the facility is ‘‘better 

than BART.’’ Finally, we are finalizing 

the TWG Alternative as the FIP 

requirements for NGS. 

EPA is promulgating four possible 

operating scenarios under the TWG 

Alternative (see Table 1). The operator 

of NGS must implement one of the four 

enforceable operating scenarios in order 

to comply with the 2009–2044 NOX

Cap. The applicable operating scenario 

will depend on the outcome of 

ownership changes related to LADWP, 

NV Energy, and Navajo Nation, as well 

as whether the operator of NGS can 

increase capacity (by no more than 189 

MW) to accommodate ownership 

changes, without triggering New Source 

Review permitting requirements, as 

described in Table 1. Once the 

ownership outcomes are finalized, the 

operator of NGS must implement the 

applicable Alternative as shown in 

Table 1. For example, if LADWP and NV 

Energy both retire their ownership 

shares of NGS and the Navajo Nation 

does not elect to purchase an ownership 

share of NGS, TWG Alternative A1 

applies and the operator of NGS must 

implement Alternative A1 and may not 

elect to implement Alternatives A2, A3, 

or B. By December 1, 2019, the operator 

of NGS must notify EPA of the 

applicable Alternative (i.e., TWG 

Alternative A1, A2, A3, or B). 

In addition to the enforceable 2009– 

2044 NOX Cap, Alternatives A1, A2, and 

A3 each has enforceable emission 

reduction measures in 2019 and 2030 

(see Table 1). Under Alternative B, in 

addition to the enforceable 2009–2044 

NOX Cap, the operator of NGS must also 

ensure that cumulative NOX emissions 

over 2009–2029 comply with the 2009– 

2029 NOX Cap. The 2009–2029 NOX

Cap is calculated based on emissions 

that would have been emitted over that 

period under Alternative A1. Under all 

Alternatives, if, based on required 

annual reports submitted by the 

operator of NGS to EPA, cumulative 

emissions of NOX from NGS exceed the 

2009–2044 NOX Cap at any time prior 

to December 31, 2044, the operator of 

NGS must permanently cease operation 

of NGS. In addition, under Alternative 

B, if cumulative emissions of NOX

exceed the 2009–2029 NOX Cap prior to 

2029, the operator of NGS must 

temporarily cease operation of all units 

at NGS.33 Under all Alternatives, the 

operator must permanently cease 

operation of all units at NGS by 

December 22, 2044. 

Under all TWG Alternatives, the 

operator of NGS must report to EPA 

annual emissions and heat input data 

and must make this information 

publicly available on its Web site. In 

addition, under TWG Alternative B, the 

operator must also submit to EPA 

annual Emission Reduction Plans 

projecting year-by-year emissions 

covering the 2020–2029 and 2030–2044 

periods so that there is a plan for 

operation of NGS that ensures that 

cumulative emissions of NOX do not 

exceed the 2009–2029 NOX Cap and the 

2009–2044 NOX Cap. Although year-byyear emissions projected in the annual 

Emission Reduction Plans are not 

enforceable (i.e., emissions in a given 

year are not required to match 

projections for that year in an Emission 

Reduction Plan), the requirement to 

submit Emission Reduction Plans is 

enforceable, and provides the operator 

with a framework for planning for future 

emissions reductions. The requirement 

also provides EPA and the public the 

opportunity to monitor and evaluate 

progress of emission reductions under 

TWG Alternative B. 

TABLE 1—SUMMARY OF THE MAJOR REGULATORY PROVISIONS OF THE TWG ALTERNATIVE

Applicability 

(Step 1) ...................... • If LADWP and NV Energy both exit NGS without selling their ownership interests 

(i.e., retire shares), or both exit by selling to an existing NGS participant; or one retires shares and the other sells to an existing NGS participant; and 

• If LADWP or NV Energy 

sells to a 3rd party, or 

does not exit NGS; 

(Step 2) ...................... • If Navajo Nation does 

not purchase ownership 

share by 12/31/19; 

• If Navajo Nation purchases up to 170 MW 

by 12/31/19; and 

• If Navajo Nation purchases up to 170 MW 

by 12/31/19; and 

• n/a. 

(Step 3) ...................... • n/a ................................. • If Participants increase 

capacity without triggering permit requirements; 

• If Participants cannot increase capacity without 

triggering permitting); 

• n/a. 

Applicable Alternative ........ Then TWG Alternative A1 

applies.

Then TWG Alternative A2 

applies.

Then TWG Alternative A3 

applies.

Then TWG Alternative B 

applies. 

Applicable Requirements .. • Comply with 2009–2044 NOX Cap of 494,899 tons. 

• Permanently cease operation of all units if cumulative emissions before 2044 exceed 2009–2044 NOX Cap. 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46519 

34See page 14 of the TWG Agreement (section 

IV.F). This section of the TWG Agreement also 

states that ‘‘[a]t its election, consistent with the 

Lease Amendment, the Navajo Nation may continue 

plant operations at NGS after December 22, 2044 

consistent with EPA approval.’’ EPA is not 

including this provision into the regulatory 

requirements at § 49.5513(j)(3)(iii), however, EPA 

expects that NGS would be substantially modified 

if the Navajo Nation elects to continue operation of 

the facility after NGS ceases conventional coal-fired 

generation in 2044, and that NGS must then meet 

all applicable regulatory and permitting 

requirements in existence at that time. 

35We note that in our Supplemental Proposal, we 

reported the affirmative defense provisions as 

paragraphs (c)(1) and (g)(3) in error. The correct 

citations are to paragraph (c)(2) and paragraph (i) 

of 40 CFR 49.5513. 

TABLE 1—SUMMARY OF THE MAJOR REGULATORY PROVISIONS OF THE TWG ALTERNATIVE—Continued 

• Permanently cease conventional coal-fired electricity generation by December 22, 2044. 

Additional Emission Cap ... • n/a • Comply with 2009–2029 

NOX Cap of 416,865 

tons. 

Specific Requirements * .... • By 12/31/19 permanently close 1 unit.• By 12/31/19 permanently close 1 unit.• By 12/31/19 reduce net 

generating capacity by 

no less than 561 MW.

• Temporarily cease operation if cumulative emissions before 2029 exceed 2009–2029 NOX

Cap. 

• By 12/31/30 meet NOX

limit of 0.07 lb/MMBtu 

on 2 units.

• By 12/31/19 operator 

may increase capacity 

by no more than 189 

MW.

• By 12/31/30 meet NOX

limit of 0.07 lb/MMBtu 

on 2 units.

• By 12/31/30 meet 0.07 

lb/MMBtu on 2 units.

Reporting ........................... • By December 1, 2019, notify EPA of applicable Alternative (A1, A2, A3, or B). 

• Submit annual report summarizing heat input and annual and cumulative emissions of NOX. 

• Make annual report publicly available on Web Site. 

• Submit application to revise Part 71 Operating Permit by December 31, 2020. 

Additional Reporting .......... • n/a • By 12/31/19 and annually thereafter submit 

Emission Reduction 

Plans to project year-byyear emissions to assure compliance with 

NOX Caps. 

* All units must comply with the existing NOX emission limit of 0.24 lb/MMBtu established in a 2008 permitting action. See discussion in Proposed Rule at 78 FR 8284 (February 5, 2013). This limit applies to each unit unless otherwise stated. 

In our final rule, EPA has included 

several revisions to the proposed 

regulatory text (40 CFR 49.5513(j)) put 

forth in the Supplemental Proposal. The 

substantive revisions include: 

1. Revision to § 49.5513(j)(3) to clarify 

that EPA is finalizing a ‘‘better than 

BART’’ Alternative; 

2. Additions to § 49.5513(j)(3) to 

specify that the operator must 

temporarily cease operation of NGS if 

cumulative emissions of NOX exceed 

the 2009–2029 NOX Cap of 416,865 tons 

at any time prior to December 31, 2029 

(under Alternative B), and must 

permanently cease operation of NGS if 

cumulative emissions of NOX exceed 

the 2009–2044 NOX Cap of 494,899 tons 

at any time prior to December 31, 2044 

(under all Alternatives); 

3. Additions to § 49.5513(j)(3)(i)(A)(2), 

(B)(3), and (C)(2), to specify that the 

NOX emission limit of 0.07 lb/MMBtu is 

to be calculated based on a rolling 

average basis of 30 boiler operating 

days; 

4. Correction to § 49.5513(j)(3)(ii)(D), 

to specify that Alternative B shall also 

apply if either of the Departing 

Participants (i.e., LADWP or NV Energy) 

remains as a participant in NGS; 

5. Addition of § 49.5513(j)(3)(iii), 

consistent with the TWG Agreement, to 

require the owners of NGS to cease its 

operation of conventional coal-fired 

generation at NGS no later than 

December 22, 2044;34

6. Addition to § 49.5513(j)(4)(ii), to 

change the annual reporting date to 

begin in 2015 instead of the specific 

date of January 31, 2015, and specify 

that the report must be submitted to 

EPA and also made publicly-available 

within 30 days of the submittal deadline 

associated with the annual emission 

inventory required by the Part 71 

Operating Permit for NGS; 

7. Addition to § 49.5513(j)(4)(iii), to 

clarify that the Part 71 Operating Permit 

for NGS shall incorporate practically 

enforceable limits for NOX of 0.24 lb/

MMBtu, on a 30-day rolling average 

basis, for each Unit equipped with LNB/ 

SOFA, and 0.07 lb/MMBtu, on a rolling 

average basis of 30 boiler operating 

days, for each Unit equipped with SCR, 

as federally enforceable permit 

conditions; and 

8. Addition of § 49.5513(j)(4)(iv)(C), to 

specify that the requirement to submit 

annual Emission Reduction Plans 

beginning no later than December 31, 

2019, must be incorporated into the Part 

71 Operating Permit for NGS as a 

federally enforceable permit condition. 

9. Revision to § 49.5513(j)(7) to 

require the owner or operator of NGS to 

maintain records that document 

compliance with the NOX Cap (e.g., 

daily emissions and heat input data) for 

the life of the facility, rather than at 

least five years. 

10. Deletion of § 49.5513(j)(7)(vi) that 

required record-keeping of all major 

maintenance activities conducted on 

emission units, air pollution control 

equipment, and CEMS because recordkeeping of maintenance activities are 

not needed to ensure compliance with 

the 2009–2029 and 2009–2044 NOX

Caps. 

11. Revision to § 49.5513(j)(11) to 

state that the affirmative defense 

provisions of paragraphs § 49.5513 (c)(2) 

and § 49.5513(i) do not apply to 

paragraph § 49.5513(j).35

Revision (1) above is necessary to 

clarify that EPA is finalizing a ‘‘better 

than BART’’ alternative in lieu of BART. 

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46520 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

36See final action for the previous FIP for NGS 

at 75 FR 10179 (March 5, 2010). 

37NRDC v. EPA, 2014 U.S. App. LEXIS 7281 (D.C. 

Cir.), in the docket for this rulemaking. 

38 Id. at 24 (arguments that violations were caused 

by unavoidable technology failure can be made to 

the courts in future civil cases when the issue 

arises). 39See document number 0182 (Pre-publication 

version of Supplemental Proposal for NGS Signed 

on September 25, 2013), posted to docket on 

September 25, 2013 and publication of 

Supplemental Proposal in Federal Register at 78 FR 

62509 (October 22, 2013). 

40See document titled ‘‘EPA Responses to 

Comments on Final Rule for NGS’’ in the docket for 

this rule. 

The BART Benchmark used to assess 

the ‘‘better than BART’’ alternative is 

based on our proposed BART 

determination for NGS, and the ‘‘better 

than BART’’ alternative is consistent 

with our Supplemental Proposal of the 

TWG Alternative. Revision (3) above is 

necessary because EPA inadvertently 

did not specify the averaging period 

associated with the emission limits for 

NOX in our Supplemental Proposal. 

Revisions (2) and (4) through (10) above 

are in response to comments submitted 

to EPA on our Supplemental Proposal. 

Revision (11) above amends a proposed 

provision in our Supplemental Proposal 

that limited the applicability of the 

existing affirmative defense provisions 

for startups, shutdowns, and 

malfunctions (from the previous FIP for 

NGS codified at 40 CFR 49.5513(c)(2) 

and 40 CFR 49.5513(i)) to 

malfunctions.36 In this Final Action, we 

are revising (j)(11) to make clear that the 

existing affirmative defense provisions 

do not apply to the emission limits 

established in the TWG Alternative. 

Following the close of the public 

comment period, the United States 

Court of Appeals for the DC Circuit 

issued a decision concerning various 

aspects of the NESHAP for Portland 

cement plants issued by EPA in 2013, 

including the affirmative defense 

provision of that rule.37 The court found 

that EPA lacked authority to establish 

an affirmative defense for private civil 

suits and held that under the CAA, the 

authority to determine civil penalty 

amounts lies exclusively with the 

courts, not EPA. The court did not 

address whether such an affirmative 

defense provision could be properly 

included in a SIP. However, the court’s 

holding makes it clear that the CAA 

does not authorize promulgation of such 

a provision by EPA. In particular, the 

court’s decision turned on an analysis of 

CAA sections 113 (Federal enforcement) 

and 304 (Citizen suits). These 

provisions apply with equal force to a 

civil action brought to enforce the 

provisions of a FIP. The logic of the 

court’s decision thus applies to the 

promulgation of a FIP and precludes 

EPA from including an affirmative 

defense provision in a FIP. Therefore, 

we are not including an affirmative 

defense provision in the final FIP. 

We note that, if a source is unable to 

comply with emission standards as a 

result of a malfunction, EPA may use 

case-by-case enforcement discretion, as 

appropriate. Further, as the DC Circuit 

recognized, in an EPA or citizen 

enforcement action the court has the 

discretion to consider any defense 

raised and determine whether penalties 

are appropriate.38

IV. Summary of Major Issues Raised by 

Commenters 

The public comment period for our 

Proposed Rule opened on February 5, 

2013. On two occasions, we extended 

the comment period on our Proposed 

Rule at the request of stakeholders, with 

a final closing date of January 6, 2014. 

Although we posted the pre-publication 

version of our Supplemental Proposal to 

the docket and to our Web site on 

September 25, 2013, the public 

comment period for the Supplemental 

Proposal officially began when it was 

published in the Federal Register on 

October 22, 2013.39 We accepted public 

comments on our Supplemental 

Proposal, concurrently with our 

Proposed Rule, until January 6, 2014. 

Our Supplemental Proposal also 

included notice of five public hearings, 

one on the Navajo Nation, one on the 

Hopi reservation and three in the State 

of Arizona. The public hearings 

occurred during the week of November 

12, 2013. In all, 194 oral testimonies 

were presented at the public hearings. 

We received over 77,000 written 

comments. Of these, over 76,800 

comments came from private 

individuals who submitted substantially 

similar comments by email or postcard. 

We received an additional 300 unique 

written comments (not including 

duplicates, requests for extension of the 

public comment period, or requests for 

additional hearings) from a variety of 

individuals and entities, including tribal 

governments, environmental or public 

interest advocacy groups, water interest 

groups, groups representing industry or 

commerce, the operator and participants 

in NGS and the Kayenta Mine, elected 

officials, and state and local 

governments. 

In this document, EPA is providing an 

abbreviated summary of the major 

comments and EPA’s responses to those 

comments, grouped together by subject 

matter. The complete response to 

comments document (RTC) includes the 

full summary of all substantive 

comments and EPA’s full responses to 

those comments. The RTC is included 

in the docket for this rulemaking.40 We 

are not responding to comments 

unrelated to our Proposed Rule or 

Supplemental Proposal for NGS in this 

document or in the RTC. 

A. General Comments From Public 

Hearings 

Comment: Contribution of NGS to the 

local and state economy and support for 

TWG Alternative 

Many commenters at the public 

hearings preferred the TWG Alternative 

because they believe that EPA’s 

proposed BART determination would 

force NGS and the Kayenta Mine to 

close, causing economic harm to an area 

where the majority of residents are lowincome and where opportunities for 

employment are limited. Many 

commenters stressed that NGS employs 

over 500 people and the Kayenta Mine 

has over 400 employees, and the loss of 

these jobs would only exacerbate the 

unemployment rate in the area, which 

currently ranges from 47 percent to 60 

percent. 

A number of commenters noted that 

NGS supplies more than 90 percent of 

the energy used by Central Arizona 

Water Conservation District (CAWCD), 

which operates the Central Arizona 

Project (CAP), which transfers water 

from the Colorado River throughout 

Arizona. A few commenters urged EPA 

to uphold its federal trust obligations 

and ensure that tribal communities 

continue to have access to affordable 

water, and advised EPA to make a 

decision consistent with the legal rights 

that the Gila River Indian Community 

and other stakeholders negotiated and 

that Congress granted under the Arizona 

Water Settlements Act of 2004. 

A few commenters support the TWG 

Alternative because they believe it is a 

fair compromise created by a diverse 

group of stakeholders that provides a 

path for future operation at NGS by 

allowing for potential ownership 

changes and by providing an extension 

to install SCR technology, while still 

ensuring that the total emission 

reductions of NOX will be greater than 

those achieved under EPA’s proposed 

BART determination. 

Response: EPA recognizes the 

contribution of NGS and the Kayenta 

Mine to the economy of the Navajo 

Nation, the Hopi Tribe, the city of Page, 

and the state of Arizona. In our 

Proposed Rule, EPA discussed the 

history of NGS and the relationship 

between NGS, the Central Arizona 

Project, and numerous tribes located in 

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41See 78 FR 8274, at 8275 (February 5, 2013). 

42 Id. and 78 FR 62509 (October 22, 2013). 

43Emissions of HAPs from various source 

categories are addressed generally through the 

NESHAP. EPA addressed mercury emissions from 

power plants specifically in the final Mercury and 

Air Toxics Standard (MATS). 77 FR 9304 (February 

16, 2012). 44http://www.epa.gov/climatechange/basics/. 45http://www.epa.gov/climatechange/

EPAactivities.html. 46See http://www2.epa.gov/carbon-pollutionstandards. 47For more information, please see www.ngskmceis.net. 48http://www.epa.gov/otaq/. 49See, e.g., 76 FR 74854, at 74900 (December 1, 

2011). 

Arizona.41 EPA notes that NGS is a 

facility that is subject to the BART 

requirement of the RHR, and emissions 

from NGS affect visibility at 11 national 

parks and wilderness areas in the 

Southwest. The analyses in our 

Proposed Rule and Supplemental 

Proposal determined that additional 

controls at NGS are cost-effective, will 

significantly reduce the contribution of 

NGS to visibility impairment at 

numerous Class I areas, and should not 

cause NGS to retire. However, for a 

number of reasons, including the 

importance of NGS to numerous Indian 

tribes located in Arizona and the federal 

government’s reliance on NGS to meet 

the requirements of water settlements 

with several tribes, EPA also outlined a 

framework for considering ‘‘better than 

BART’’ alternatives that ensures 

emission reductions while providing 

additional flexibility to the operator of 

NGS.42

EPA agrees with comments that the 

TWG Agreement represents a 

compromise between diverse 

stakeholders, although we recognize 

that the members of the TWG did not 

invite all affected stakeholders to 

participate in their discussions. The 

TWG Alternative provides certainty for 

future operation of NGS, flexibility in 

the compliance timeframe, and more 

emission reductions of NOX than would 

have been achieved under EPA’s 

proposed BART determination. Based 

on our analysis in our Supplemental 

Proposal and consideration of all 

comments received, EPA is taking 

action to finalize requirements 

consistent with the TWG Agreement we 

put forth in our Supplemental Proposal, 

i.e., the TWG Alternative. 

Comment: Impact of air pollutants 

from NGS on public health and welfare 

and support for proposed BART 

determination. 

Several commenters favor EPA’s 

proposed BART determination for NGS 

because they believe that emissions 

from NGS cause health problems in the 

area, including respiratory illness and 

heart disease. One commenter cited a 

Clean Air Task Force study which states 

that NGS is responsible for 

approximately $127 million in health 

costs every year. Many of these 

commenters urged EPA to conduct 

health studies to determine the actual 

impact to health in these communities. 

Some commenters favor stringent 

controls because they believe that 

emissions from NGS adversely affect 

native plant species and harm 

traditional dry land farming. Others 

assert that emissions from NGS can be 

linked to high levels of mercury found 

in fish species located in nearby lakes. 

Many commenters expressed concerns 

over the well-being of the Navajo 

Aquifer. A number of commenters favor 

stringent controls because they believe 

that emissions produced from NGS 

contribute to climate change. 

In contrast, a few commenters 

questioned the extent to which 

emissions from NGS impact public 

health and the environment, asserting 

that the haze is a result of emissions 

from natural sources (e.g., volcanoes, 

wind/dust storms, and forest fires) and 

pollution produced from nearby cities 

(i.e., Phoenix, Los Angeles, and Las 

Vegas). Another commenter asserted 

that EPA’s Web site states that vehicles 

are the largest producers of NOX

emissions in the country and concludes 

that EPA is ignoring mobile sources and 

unfairly targeting stationary sources. 

Some commenters preferred EPA’s 

proposed BART determination over the 

TWG Alternative because they believe 

that the alternative is based on a false 

premise. They asserted that the closure 

of a single unit is not equivalent to 

cleaning up all three units because the 

reduction in capacity will ultimately 

require new electricity generation 

elsewhere because the demand for 

power does not change. 

Response: Protection of human health 

and the environment is EPA’s mission 

and forms the basis for many Agency 

actions, including establishing the 

National Ambient Air Quality Standards 

(NAAQS), and promulgation of 

regulations such as the New Source 

Performance Standards (NSPS) and the 

National Emission Standards for 

Hazardous Air Pollutants (NESHAP). In 

addition to Clean Air Act requirements 

to protect human health, in the 1977 

Clean Air Act Amendments, Congress 

declared 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 (See CAA 

§ 169A). 

EPA agrees that visibility-impairing 

pollutants are among the same 

pollutants that affect human and 

ecosystem health; however, health 

studies are beyond the scope of this 

BART analysis. Similarly, hazardous air 

pollutants (HAPs), such as mercury, are 

not visibility-impairing pollutants and 

therefore are beyond the scope of this 

BART analysis.43

EPA agrees that climate change is an 

important issue.44 However, the RHR 

addresses pollutants that impair 

visibility and is not intended to address 

pollutants that contribute to climate 

change. EPA has developed various 

programs and activities to address 

emissions of greenhouse gases.45 On 

June 2, 2014, EPA signed a proposal to 

cut greenhouse gas emissions from coalfired power plants by up to 30 percent 

by 2030.46 Although regulation of 

greenhouse gases is conducted under 

separate statutory requirements from 

regional haze, EPA is mindful that this 

BART determination for NGS is not the 

only regulatory program that affects this 

facility and the region. 

EPA agrees with comments that 

mining and combustion of coal affect 

the environment. EPA notes that 

Reclamation has started its process to 

develop an Environmental Impact 

Statement (EIS) required under the 

National Environmental Protection Act 

(NEPA) for activities resulting from the 

continued operation of NGS and the 

Kayenta Mine.47 The on-going NEPA 

process provides numerous 

opportunities and the appropriate forum 

to raise concerns related to the impacts 

of mining and use of water from the 

Navajo Aquifer. We further note that 

representatives of DOI attended all the 

public hearings on NGS held by EPA 

and are aware of the issues raised by 

commenters during the BART process 

regarding mining and the Navajo 

Aquifer. 

EPA disagrees with the assertion that 

EPA is unfairly targeting stationary 

sources of emissions and ignoring the 

significant contribution of motor vehicle 

emissions. Consistent with title II of the 

CAA, the EPA Office of Transportation 

and Air Quality protects public health 

and air quality by, among other things, 

regulating air pollution from motor 

vehicles, engines, and the fuels to 

operate them.48 New cars and sport 

utility vehicles sold today have 

emission levels of hydrocarbons, NOX, 

and carbon monoxide that are 98–99 

percent lower than new vehicles sold in 

the 1960s on a per mile basis.49

Similarly, standards established for 

heavy-duty highway and non-road 

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46522 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

50See Fact Sheet for Tier 3 Standards available 

at http://www.epa.gov/otaq/documents/tier3/

420f14010.pdf. 

51See RTC and references therein. 

52http://www.epa.gov/environmentaljustice/. 

53See page 25 of the TSD to the February 5, 2013 

Proposed Rule. 

54See, for example document number 0232 in the 

ANPR docket at EPA–R09–OAR–2009–0598, and 

document numbers 0008 and 0009 in the docket for 

this rule. 

55See, for example, document number 0150, 

0152, 0166, 0173, 0302, and 0303 in the docket for 

this rule. 

56See document number 0122 in docket for this 

rule. 

57See document numbers 0182, 0183, and 0184 

in the docket for this rule. 

58EPA engaged with the government of the Hopi 

Tribe to search for an oral interpreter between 

English and the Hopi language, but the Hopi Tribe 

was unable to locate anyone to provide those 

services. 

sources require emission rate reductions 

on the order of 90 percent or more for 

particulate matter and NOX. In 2014, 

EPA finalized new vehicle emission 

standards and reduced the fuel sulfur 

content of gasoline to achieve additional 

reductions in tailpipe and evaporative 

emissions from passenger cars, lightduty vehicles, medium-duty passenger 

cars, and some heavy-duty vehicles 

starting in 2017.50

EPA agrees that forest fires and 

volcanic eruptions, when they occur, 

can impact visibility to a greater extent 

than anthropogenic sources of 

emissions. However, Congress directed 

EPA to develop rules to address ongoing emissions from stationary sources 

subject to BART to remedy the existing 

impairment of visibility in Class I areas 

and restore visibility to natural 

conditions. 

EPA disagrees with assertions that the 

TWG Alternative is based on a false 

premise because the closure or 

curtailment of one unit would just result 

in electricity being produced elsewhere. 

Closure of one unit at NGS or the 

curtailment of an equivalent amount of 

electricity generation is possible based 

on LADWP and NV Energy’s intended 

divestiture from NGS. Consistent with 

state law in California and Nevada, 

additional electricity needed to replace 

lost generation from NGS, associated 

with LADWP and NV Energy’s 

divestiture, would come from energy 

sources that emit less air pollution than 

a conventional coal-fired power plant 

operating with SCR on all units.51

Comments regarding specific aspects 

of the TWG Alternative are discussed in 

Section 9.0 of the RTC. 

Comment: Environmental and Social 

Justice. 

Several commenters consider the 

presence of NGS and several other 

power plants in and around the Navajo 

Nation to represent an environmental 

and economic justice issue. One 

commenter noted that a Navajo water 

hauler in Kaibeto, a Navajo community 

near Page, pays 10 to 20 times more for 

water, or $13,000 per acre foot, than 

municipal CAP water users in Glendale 

or a farmer in Tempe, who pay $551 and 

$41 per acre feet, respectively. 

Several commenters opined that the 

leaders of the Navajo Nation and EPA 

have not protected the interests of the 

local population. A few expressed 

concerns over how the alternatives were 

written, noting that many tribal 

residents do not understand the 

technical language used in the 

documents and therefore cannot 

adequately comment on the validity of 

the alternatives proposed. Some 

commenters argued that pollution can 

be controlled using existing technology 

and EPA should apply the same 

standard to NGS as other coal-burning 

power plants (e.g., Four Corners Power 

Plant). A few commenters argued that 

extending the compliance timeframe for 

NGS demonstrates that the federal 

government considers itself exempt 

from federal law. Several argued that 

tribal communities do not have the 

funds to develop proposals and/or 

conduct environmental assessments and 

urged that EPA uphold federal trust 

responsibilities and create an equal 

playing field. 

Response: EPA defines Environmental 

Justice as ‘‘the fair treatment and 

meaningful involvement of all people 

regardless of race, color, national origin, 

or income with respect to the 

development, implementation, and 

enforcement of environmental laws, 

regulations, and policies. EPA has this 

goal for all communities and persons 

across the country. It will be achieved 

when everyone enjoys the same degree 

of protection from environmental and 

health hazards and equal access to the 

decision-making process to have a 

healthy environment in which to live, 

learn, and work.’’ 52

EPA takes fair treatment and 

meaningful involvement seriously and 

provided numerous opportunities for 

tribal governments, environmental and 

tribal non-governmental organizations, 

and other interested stakeholders to 

provide input in the development of our 

Proposed Rule, Supplemental Proposal, 

and Final Rule for NGS. EPA began our 

public involvement process for a BART 

determination for NGS in 2009, when 

we published an Advanced Notice of 

Proposed Rulemaking (ANPR). 

Although we initially provided a 30-day 

public comment period, at the request of 

tribal governments and other interested 

stakeholders, we extended the comment 

period for tribes another 30 days to 

October 28, 2009 and, to allow 

additional time for government-togovernment consultation on NGS, 

agreed to accept comments from tribes 

until March 1, 2010. 

EPA received over 6,000 comments on 

the ANPR.53 During 2009 through 2012, 

EPA met with various stakeholders, 

including tribal governments and tribal 

environmental groups, to discuss NGS 

and hear concerns related to a BART 

determination for this facility.54 We 

initially provided a 90-day comment 

period for the Proposed Rule on 

February 5, 2013, and at the request of 

various stakeholders, we provided 

several extensions of the public 

comment period, which closed on 

January 6, 2014. During the 11-month 

comment period, EPA continued to 

meet with stakeholders, at their request, 

to discuss our proposed BART 

determination for NGS and our 

framework for ‘‘better than BART’’ 

alternatives.55

On July 26, 2013, the TWG submitted 

Appendix B to the TWG Agreement to 

EPA for consideration. EPA posted the 

TWG Agreement to our docket on the 

same day to provide the public an 

opportunity to review it.56 On 

September 25, 2013, EPA posted our 

Supplemental Proposal, along with 

supporting documents, to the docket to 

allow for pre-publication review by 

interested parties.57 The Supplemental 

Proposal was published in the Federal 

Register on October 22, 2013. The 

comment period for the Supplemental 

Proposal closed on the same day as the 

BART proposal, on January 6, 2014. The 

Supplemental Proposal also included 

notice of five open house and public 

hearing events EPA scheduled 

throughout Arizona in November 2013. 

The open houses allowed members of 

the public an opportunity to talk with 

representatives from EPA and ask 

questions. EPA held events at the 

LeChee Chapter House, located on the 

Navajo Nation, as well as in Page, 

Arizona, and provided oral 

interpretation services between English 

and Dine ́ (the Navajo language). EPA 

also held an event at the Hopi Day 

School, located in Kykotsmovi, the seat 

of the Hopi tribal government.58 Finally, 

we also held events in Phoenix and in 

Tucson, Arizona, to allow stakeholders 

in central and southern Arizona, 

representing CAP water interests and 

several tribes receiving CAP water, the 

opportunity to provide comment and 

talk with representatives from EPA. 

Although EPA understands that the TSD 

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59See document 0219 in the docket for this rule. 

60See discussions under Executive Order 12898 

in 78 FR 8793 (February 5, 2013) and 78 FR 62520 

(October 22, 2013). 

61The OAQPS Control Cost Manual is now 

referred to as the EPA Control Cost Manual. 

62See Table 12 of the TSD to the February 5, 2013 

Proposed Rulemaking, available as document 

number 0014 in the docket for this rule. 

63See MS Excel document titled ‘‘EPA cost 

analysis for NGS’’ within document number 0004 

in the docket for this rule. 

64See Table 3 of our Proposed Rule, 78 FR 8281 

(February 5, 2013). 

65See our Proposed Rule at 78 FR 8281 (February 

5, 2013). 

and Federal Register notices include 

technical information that may be 

difficult to understand, EPA provided 

Fact Sheets and handouts, written in 

plain language, at the open house and 

public hearing events.59 EPA 

representatives were also present at the 

events to discuss and explain our 

Proposals. EPA recognizes that many 

tribal communities do not have the 

funds to develop alternative proposals 

or hire experts on their behalf; however, 

this does not diminish such 

communities’ ability to participate in 

the rulemaking process in a meaningful 

way as EPA takes seriously its 

responsibility to explain its proposal to 

all interested parties and assesses all 

comments, regardless of the form of the 

comment or whether or not the 

commenter has a technical background. 

As stated in our Proposed Rule and 

Supplemental Proposal, EPA has 

determined that these proposed rules, if 

finalized, will not have 

disproportionately high and adverse 

human health or environmental effects 

on minority or low-income populations 

because they increase the level of 

environmental protection for all affected 

populations (i.e., require emission 

reductions from NGS).60 EPA recognizes 

that some commenters may view the 

timeframe for compliance under EPA’s 

framework for BART Alternatives as an 

environmental justice issue. We note 

that the LNB/SOFA credit, an important 

component of the extended timeframe, 

was based on real, actual emission 

reductions beginning in 2009 that were 

voluntary and not required by any rule 

or regulation. We also note that the 

TWG Alternative, which calls for 

closure of one unit in 2019 (or 

equivalent curtailment) will result not 

only in greater reductions of NOX than 

would have been achieved under BART, 

but also reductions of several other 

pollutants, including SO2, PM, CO2, and 

mercury. Thus, although the TWG 

Alternative includes a compliance 

timeframe for achieving additional 

reductions in 2030, over 2009–2044, the 

TWG Alternative will result in 

reductions of additional pollutants that 

affect visibility or human health, and 

will provide an enforceable mechanism 

to ensure that NGS ceases conventional 

coal-fired electricity generation at NGS 

by the end of 2044. 

EPA recognizes that numerous 

commenters expressed frustration 

regarding social inequities related to 

costs and benefits of coal mining and 

combustion and water availability and 

cost. We recommend participating in 

the EIS process for NGS and Kayenta 

Mine to raise any concerns related to 

costs, benefits, and the environmental 

and social justice of coal mining and 

coal combustion at the Kayenta Mine 

and NGS. 

B. Comments on Factor 1—Cost of 

Controls 

Comment: EPA underestimated SCR 

costs. 

Several commenters asserted that EPA 

underestimated the cost of compliance 

by improperly reworking cost estimates 

developed for SRP by Sargent and 

Lundy (S&L) in 2010 and disregarding 

real costs that would be incurred. One 

commenter quoted the BART Guidelines 

and the final RHR to assert that although 

the use of the Control Cost Manual is 

encouraged, it is not mandated, and that 

EPA has discretion to use additional 

sources of cost information. The 

commenter believes, therefore, that the 

SRP estimates for the excluded cost 

items are appropriate to use because 

they are more precise than the generic 

statements that EPA relied upon in the 

Control Cost Manual. 

Response: EPA disagrees with the 

comment that we improperly reworked 

and underestimated the SCR cost 

estimates. We note, however, that even 

if we had relied only on the cost 

estimate provided by SRP, EPA still 

would have concluded that SCR is costeffective at NGS. 

EPA used a hybrid approach for our 

cost analysis that relied primarily on the 

cost estimates provided by SRP, but also 

followed the BART Guidelines to 

determine whether S&L included cost 

estimates for services or equipment 

associated with SCR that were not 

allowed under the EPA Control Cost 

Manual. The BART guidelines state 

‘‘[i]n order to maintain and improve 

consistency, cost estimates should be 

based on the OAQPS Control Cost 

Manual, where possible’’.61 The capital 

cost estimate EPA presented in the 

proposed rulemaking for SCR plus LNB/ 

SOFA ($541 million total for Units 1–3) 

is only 8 percent lower than the SRP 

cost estimate ($589 million). SRP’s cost 

estimate would not have changed our 

conclusion that SCR is cost-effective at 

NGS. 

As discussed in the TSD to the 

proposed rulemaking, EPA made four 

adjustments to SRP’s cost estimates for 

SCR, namely, to exclude ‘‘Owners 

Construction Management, O&M 

Support and Contract Service,’’ 

‘‘Owners Legal Support and Insurance,’’ 

and ‘‘Allowance for Funds Used During 

Construction,’’ and to use an interest 

rate of 7 percent.62 Our detailed, lineby-line analysis was included in the 

docket for this proposed rulemaking and 

provided an explanation for why we 

retained, modified, or rejected each line 

item.63 Please see the RTC for additional 

discussion of these four adjustments to 

the S&L cost analysis. 

In our proposed rule, we presented 

total capital and total annual cost 

estimates from EPA and SRP, as well as 

average and incremental costeffectiveness values based on EPA and 

SRP assumptions for total annual cost 

and total annual NOX reductions. Based 

on SRP’s analysis, average costeffectiveness of SCR+LNB/SOFA at NGS 

was less than $3,000 per ton and 

incremental cost-effectiveness of 

SCR+LNB/SOFA (compared to 

SNCR+LNB/SOFA) was approximately 

$5,300 per ton.64 EPA stated that the 

cost-effectiveness values calculated by 

both EPA and SRP for SCR+LNB/SOFA 

are lower than or within the range of 

other BART evaluations where EPA or 

a state has determined that SCR is BART 

(ranging from approximately $2,000 to 

$6,000 per ton). EPA has accordingly 

determined that SCR is cost-effective at 

NGS.65 Therefore, even if EPA accepted 

the S&L cost estimates submitted by 

SRP, as commenters suggest, EPA would 

still have determined that SCR is costeffective for NGS. 

Comment: EPA overestimated SCR 

costs. 

One commenter asserted that EPA 

overestimated the cost of installing SCR 

at NGS. Although the commenter 

supported EPA’s adjustments to the S&L 

cost estimates, the commenter asserted 

that further revisions are appropriate. 

The commenter stated that EPA 

overestimated the following costs: 

Outage costs associated with installation 

and ‘‘preinstallation’’ work; catalyst 

costs; and auxiliary power. In addition, 

the commenter asserted that EPA 

overestimated annual costs by assuming 

20 years as the basis for amortizing costs 

and using an inflated interest rate of 7 

percent. 

Although the commenter concurs 

with EPA’s conclusion that SCR plus 

LNB/SOFA is cost-effective at $2,240 

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66See, e.g., Final Regional Haze Plan for Arizona 

(Phase 1) at 77 FR 72512 at 72531 (December 5, 

2012); Final Regional Haze Plan for North Dakota 

at 77 FR 20894 at 20916–17 (April 16, 2012); Final 

Regional Haze Plan for New Mexico at 76 FR 52388 

at 52399–52400 (August 22, 2011); Final Regional 

Haze Plan for Wyoming at 79 FR 5032 at 5082 

(January 30, 2014). 

67See RTC and references therein. 

68 78 FR 8281, February 5, 2013. 

per ton of NOX removed, the commenter 

re-calculated cost-effectiveness to be 

$1,412 per ton for Unit 1, $1,331 per ton 

for Unit 2, and $1,497 per ton for Unit 

3. 

Response: EPA disagrees with the 

commenter that any revisions to EPA’s 

estimate of SCR costs are necessary. 

Even if some of the costs projected by 

S&L and used by EPA may be 

overestimated (e.g., the commenter 

points primarily to capital recovery, 

catalyst replacement costs, and costs for 

lost power generation), EPA disagrees 

that we must correct every issue of 

concern raised by the commenters in 

order to support our determination of 

the BART Benchmark. EPA made four 

specific corrections to the estimates 

provided by S&L and SRP to make the 

cost calculation methodology consistent 

with methodologies used for BART cost 

calculations nationally.66 As noted in 

other responses even if we consider the 

average and incremental cost 

effectiveness of SCR using SRP and 

S&L’s full cost projections, EPA would 

still determine that SCR at NGS is costeffective. The cost-effectiveness values 

cited by the commenter, below $1,500 

per ton, certainly suggest that SCR could 

be even more cost-effective than the 

values we relied upon in our proposal, 

but this would not change our overall 

determination that SCR is cost-effective 

for NGS. 

Comment: Updated SCR cost estimate 

from SRP. 

SRP contracted with S&L in 2013 to 

review and update the SCR cost 

estimates that were prepared in 2010. 

S&L escalated costs for inflation, and 

incorporated other minor adjustments to 

reflect a lower NOX design target. SRP’s 

revised capital cost estimates for SCR 

installation on all three units total $650 

million (in 2013 dollars) compared to 

SRP’s 2010 cost estimate of $544 

million. 

Response: EPA reviewed the updated 

2013 cost estimates developed by S&L 

and provided by SRP.67 In its 2013 cost 

report, S&L explains that it escalated 

labor and material costs, and updated 

cost estimates based on a revised design 

target of 0.03 lb/MMBtu (so that the SCR 

system is deployed as a 3+1 system 

rather than a 2+2 catalyst layer system), 

and other design features, including a 

low-load temperature control system to 

operate SCR at lower loads. S&L 

escalated several costs at rates above 6.7 

or 8 percent (e.g., freight, scaffolding). 

S&L did not make any revisions to the 

components of variable annual costs, 

including maintenance labor, auxiliary 

power, steam, and catalyst replacement. 

To be consistent with the cost estimates 

in our Proposed Rule, EPA accepted 

most of the line item costs as adjusted 

by S&L and made the same four 

adjustments to the 2013 cost estimates 

as we had applied to the 2010 cost 

estimates. These changes result in an 8 

percent difference in total capital costs 

of SCR between EPA’s 2013 estimate 

and SRP’s 2013 estimate and a 21 

percent difference in the total annual 

costs of SCR between the 2013 estimates 

from EPA and SRP (see Table 2). 

TABLE 2—COST ESTIMATES FOR SCR IN 2010 AND 2013 DOLLARS

Total capital cost 

(million) in 2010$ 

Total capital cost 

(million) in 2013$ 

Total annual cost 

(million) in 2010$ 

Total annual cost 

(million) in 2013$ 

EPA Estimate ........................................................................... $496 $598 $59 $69 

SRP Estimate .......................................................................... 544 650 75 88 

In our proposed BART determination, 

EPA also presented the average and 

incremental cost-effectiveness of 

controls, based on the combination of 

combustion controls (LNB/SOFA) and 

post-combustion controls (i.e., SNCR or 

SCR). Therefore, cost-effectiveness 

values presented in our Proposed Rule 

were based on total annual cost of SCR 

in combination with annual cost of 

LNB/SOFA (SCR+LNB/SOFA), SNCR in 

combination with LNB/SOFA 

(SNCR+LNB/SOFA) or LNB/SOFA 

alone.68 Based on the updated 2013 cost 

estimates for SCR, Table 3 shows the 

average and incremental costeffectiveness of controls, in both 2010 

and 2013 dollars, based on EPA and 

SRP assumptions for total annual cost 

and annual NOX reductions achieved by 

SCR. See RTC for further detail on costeffectiveness of SNCR+LNB/SOFA and 

LNB/SOFA. 

TABLE 3—COST EFFECTIVENESS OF CONTROLS IN 2010 AND 2013 DOLLARS

2010 $ 2013 $ 

EPA SRP EPA SRP 

SCR+ LNB/SOFA: 

Total Annual Cost * ................................................. $67.5 million ........... $80.2 million ........... $74.4 million $92.6 million. 

Annual NOX reduced (tpy) ...................................... 28,573 .................... 26,180 .................... 28,573 26,180. 

NOX Limit (lb/MMBtu) ............................................. 0.055 ...................... 0.080 ...................... 0.055 0.080.

Average Cost Effectiveness ($/ton) ........................ $2,369 .................... $3,069 .................... $2,605 $3,537. 

Incremental Cost Effectiveness (vs. LNB/SOFA) 

($/ton).

$3,522 .................... $4,889 .................... $3,899 $5,695. 

Incremental Cost Effectiveness (vs. SNCR+LNB/

SOFA) ($/ton).

$3,239 .................... $5,357 .................... $3,798 $6,647. 

* EPA’s cost effectiveness calculations represent SCR in combination with LNB/SOFA, rather than SCR alone. 

Based on the revised 2013 cost 

estimates for SCR+LNB/SOFA, the 

revised average cost-effectiveness of 

SCR+LNB/SOFA is roughly 10 percent 

higher (based on EPA’s estimates) than 

the average cost-effectiveness values 

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69For informational purposes, EPA included the 

incremental cost-effectiveness values of SCR+LNB/ 

SOFA (estimated in 2010 and 2013) compared to 

LNB/SOFA and SNCR+LNB/SOFA, but we note 

that a comparison of the percent change in 

incremental cost-effectiveness between 2010 and 

2013 is not informative because SRP did not 

provide updated cost estimates (in 2013 dollars) for 

the other control technologies. 70 40 CFR 51.308(e)(1)(ii)(B). 

reported in our Proposed Rule, and 

roughly 15 percent higher based on 

SRP’s estimates.69 The 2013 values for 

average cost-effectiveness of SCR+LNB/ 

SOFA based on EPA and SRP estimates 

are still comparable to the range of 

values determined cost-effective for SCR 

in other BART determinations. For these 

reasons, EPA continues to consider 

SCR+LNB/SOFA as cost-effective at 

NGS. 

Comment: Cost-Effectiveness of 

Presumptive BART. 

One commenter stated that in 

establishing presumptive limits in the 

BART Guidelines, EPA recognized that 

SCR is not cost-effective and that 

combustion controls such as LNB/SOFA 

represent the most cost-effective control 

options for most boiler types. The 

commenter pointed out that in 

establishing presumptive limits, EPA 

considered controls that cost less than 

$1,500 per ton to be cost-effective, and 

that the cost-effectiveness for SCR at 

NGS, which ranges from $3,000 to 

$6,000 per ton based on 2010 estimates, 

is well above this threshold. The 

commenter concluded that EPA should 

have rejected SCR and proposed LNB/

SOFA as BART for NGS. 

Response: EPA disagrees with the 

assertion that the BART Guidelines 

established a threshold for costeffectiveness against which all future 

BART determinations must compare. In 

developing the presumptive NOX limits 

for BART in 2005, EPA did not set the 

cost-effectiveness values estimated for 

combustion controls as the threshold for 

determining whether a given control 

technology was or was not costeffective. If EPA had intended the costeffectiveness values estimated in 2005 

to represent a threshold for BART, it is 

reasonable to assume that the BART 

Guidelines would have included those 

cost-effectiveness values as thresholds 

in Appendix Y, and would have 

required future cost estimates to be 

presented in 2005 dollars for 

appropriate comparison to the 

thresholds. The BART Guidelines do 

not set a numerical definition for ‘‘costeffective’’, and the analysis of 

presumptive limits uses costeffectiveness as a means to broadly 

compare control technologies, not as a 

threshold for rejecting controls for an 

individual unit or facility that exceed 

the average cost-effectiveness of 

combustion controls. In addition, as 

discussed in the RTC, a value of $1,500 

per ton is not an appropriate or relevant 

value for determining cost-effectiveness. 

Comment: Indirect costs should also 

be considered under Factor 1. 

The Gila River Indian Community 

asserted that EPA conducted the 

analysis of cost-effectiveness incorrectly 

by not including the indirect costs of the 

requirements and only considering the 

direct cost of the requirements. The 

commenter stated that EPA did not give 

sufficient consideration to the high costs 

to tribes associated with indirect 

impacts of its proposed BART 

determination. 

Response: EPA disagrees with the 

assertion that our cost-effectiveness 

analysis was incorrect because it did not 

include indirect costs in the assessment 

of the costs of compliance. The BART 

Guidelines, which States and EPA must 

follow in BART determinations for 

fossil-fuel fired power plants greater 

than 750 MW,70 focus on the direct 

costs of the pollution control equipment 

and other capital and annual costs 

associated with the control technology 

alternatives. The BART Guidelines do 

not require consideration of the cost of 

potential indirect effects of BART 

control options when assessing the costs 

of compliance. Therefore, EPA disagrees 

that our analysis for Factor 1 was 

incorrect or incomplete because it did 

not include indirect costs to tribes. EPA 

further notes that under Factor 2, the 

energy and non-air quality 

environmental impacts analysis, the 

BART Guidelines specifically require 

the energy impact analysis to consider 

direct energy impacts (e.g., parasitic 

load from certain control technologies) 

and to generally exclude indirect energy 

impacts of controls (e.g., energy to 

produce raw materials for construction 

of control equipment) unless the 

indirect impact is unusual or 

significant. 

However, because of the unique 

relationship between NGS, tribes, and 

tribal water settlement agreements, and 

to inform our government-togovernment consultation with tribes, 

EPA did consider potential indirect 

effects of control options to tribes under 

Factor 2. EPA quantified the impact to 

electricity rates and CAP water rates, 

and also assessed whether installation 

of SCR would result in electricity 

generation costs at NGS that exceed the 

cost to purchase power on the wholesale 

market. Therefore, although EPA 

appropriately did not consider indirect 

costs in our analysis of Factor 1, EPA 

did include consideration of indirect 

impacts to tribes and other entities in 

our analysis of Factor 2. 

C. Comments on Factor 2—Energy and 

Non-Air Quality Environmental 

Impacts, Including Economic Impacts 

Comment: EPA’s Affordability 

Analysis relied on invalid assumptions. 

One commenter submitted a report, 

prepared by Management Information 

Services, Inc. (MISI report), asserting 

that EPA made several assumptions that 

underestimated the cost of continuing to 

operate NGS with additional controls, 

including the assumption that no new 

capital would be deployed at NGS over 

the next 25 years, the assumption that 

the increase in the annual NGS lease 

cost would be $15 million per year 

(which is lower than actual increase in 

lease cost of $43 million per year that 

was released after publication of our 

Proposed Rule), and the use of EPA’s 

capital cost estimates for SCR instead of 

the cost estimated by S&L. 

Other commenters asserted that EPA 

underestimated the cost of closing NGS 

and purchasing power on the wholesale 

market, by not accounting for costs 

associated with stranded investments 

and decommissioning NGS. 

Response: EPA recognizes the 

economic importance of NGS to the 

State of Arizona, the Navajo Nation, and 

the Hopi Tribe. The purpose of the 

Affordability Analysis in our docket was 

to determine whether the control 

options for BART would have a 

detrimental impact on the 

competitiveness of NGS in the western 

power market, affecting whether the 

NGS owners would continue to operate 

NGS or replace NGS generation with 

less expensive market power. The 

Affordability Analysis indicated that, 

even if SCR installation was required on 

all three units at NGS, power produced 

at NGS would remain less expensive 

than the cost to replace power through 

wholesale purchases. Because utilities 

will generally provide power to their 

customers in a least-cost manner and 

because NGS, with the installation and 

operation of SCR, remained the less 

expensive option, EPA determined that 

the operation and installation of SCR, in 

and of itself, was not likely to force NGS 

to close. 

In response to multiple comments 

expressing concern related to 

simplifying assumptions or outdated 

data, EPA updated the Affordability 

Analysis with the most current power 

market price curves from the U.S. 

Energy Information Administration 

(EIA) and recent forward power market 

prices in March 2014 and other more 

current modeling variables. These 

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71See RTC and references therein. 

72See BART Guidelines at 70 FR 39169 (July 6, 

2005). 

73See Proposed Rule at 78 FR 8282 (February 5, 

2013) and TSD at pages 71–72. 

74See Proposed Rule at 78 FR 8283 (February 5, 

2013). 

75See EPA, 2010, ‘‘Summary of Expert Opinions 

on the Existence of a Threshold in the 

Concentration-Response Function for PM2.5-related 

revisions are discussed in more detail in 

the RTC as well as in additional 

supporting documents.71 The updated 

model results, comparing the net 

present value (NPV) of electricity 

generation costs with air pollution 

controls installed compared to the costs 

to purchase an equivalent amount of 

power on the wholesale market, are 

summarized in the RTC. Overall, the 

combined changes do not change the 

conclusions from the original 

Affordability Analysis that installing 

and operating SCR at NGS would be less 

costly than closing NGS and purchasing 

replacement power from the wholesale 

market. 

Comment: EPA’s failure to 

appropriately consider the impacts to 

non-Indian agricultural (NIA) water 

users renders its Factor 2 analysis 

arbitrary, capricious, and an abuse of 

discretion. 

One commenter stated that, as a result 

of errors and omissions, EPA’s Factor 2 

analysis is arbitrary, capricious, and an 

abuse of discretion. The commenter 

asserted that there are several problems 

with the EPA analysis related to NIA 

users of CAP water, including erroneous 

assumptions, insufficient support for 

conclusions, failure to consider 

decreased farming profitability and 

increased unemployment, failure to 

acknowledge the inability of NIA water 

users to pass along cost increases as 

compared to municipal users, and other 

factors. 

Response: EPA recognizes that CAP 

water is an important resource for NIA 

and other users of water in Arizona. As 

a result, as one of a number of 

discretionary analyses EPA conducted 

on the indirect impacts on major 

stakeholders, EPA calculated water rate 

increases to NIA users of CAP water and 

municipal and industrial users of CAP 

water. 

EPA disagrees that our discussion of 

impacts to NIA users of CAP water 

renders our Factor 2 analysis arbitrary, 

capricious, and an abuse of discretion. 

Neither the CAA nor the BART 

Guidelines require consideration of 

indirect costs or indirect impacts of 

controls in a BART analysis. EPA, 

nevertheless, included an evaluation of 

impacts to some of the major 

stakeholders in NGS in our BART 

analysis under Factor 2, including NIA 

users, as consistent with the statement 

in the BART Guidelines that ‘‘the energy 

impacts analysis may consider . . . 

whether a given alternative would result 

in significant economic disruption or 

unemployment’’ (emphasis added).72

EPA recognizes that the information 

we had available to us about NIA users 

of CAP water was limited, and we 

acknowledged in the TSD to our 

Proposed Rule that we had several 

questions about CAP and groundwater 

availability to NIA water users. EPA 

appreciates the clarifications and 

additional information provided by NIA 

users of CAP water during the comment 

period for our proposals. The additional 

information provided during the 

comment period about NIA users of 

CAP water does not change our 

conclusion under Factor 2, that the 

potential economic impacts to tribes 

argue for flexibility in the compliance 

timeframe for NGS, because this 

compliance flexibility also benefits 

other stakeholders, including the NIA 

users of CAP water. 

Comment: EPA must evaluate 

cumulative economic impact of other 

rulemakings. 

One commenter asserted that the 

BART proposal must take into account 

the context in which the regional haze 

rules are being implemented and 

conduct a cumulative impact analysis of 

all EPA rulemakings. The commenter 

noted that the two remaining copper 

smelters in Arizona are already subject 

to BART for SO2 and they also have to 

make significant capital investments to 

comply with other regulatory programs 

and initiatives such as the revised SO2

NAAQS. 

Response: EPA disagrees with the 

assertion that we must consider the total 

cost impact of all EPA regulatory 

requirements in a BART analysis. EPA 

recognizes that other facilities, whose 

water and electricity rates may be 

affected by our BART determination for 

NGS, may also be subject to BART for 

their own emissions of visibilityimpairing pollutants. As a general 

matter, EPA is mindful that facilities 

may be affected by multiple regulatory 

and program activities. We note that 

BART is a case-by-case determination 

that is based on a source-specific 

analysis of five factors, which include 

considerations of the unique 

circumstances of each affected facility, 

as required under the CAA. 

Comment: Impact to the Development 

Fund. 

One commenter stated that the 

increased cost of electricity generation 

associated with SCR would reduce the 

competitiveness of the price of NGS 

power on the wholesale market and 

therefore reduce the revenue that flows 

into the Development Fund. 

Response: As discussed in our 

Proposal Rule and TSD, EPA recognizes 

that any electricity owned by 

Reclamation based on its 24.3 percent 

participation in NGS that is not used by 

CAP is sold and revenues are deposited 

into the Development Fund.73 This fund 

is authorized to pay the delivery portion 

of the cost of CAP water for certain 

Indian tribes and to pay the cost of 

constructing delivery systems to bring 

CAP water to certain Indian tribes.74

EPA considers the potential economic 

impacts to tribes, including potential 

impacts to the Development Fund, as 

part of BART factor 2 to support the 

appropriateness of flexibility in the 

compliance timeframe for NGS. 

Comment: No basis for public health 

claim. 

One commenter asserted that EPA has 

no basis for claiming that the NOX

reductions from NGS would lead to a 

public health benefit. The commenter 

noted that EPA establishes NAAQS at 

levels that are protective of public 

health and welfare with an adequate 

margin of safety that accounts for 

sensitive populations such as children 

and the elderly, and that EPA has never 

found that any of the areas around NGS 

fail to attain the NAAQS. The 

commenter asserted that EPA must 

conduct a health risk evaluation that 

follows the four basic steps of the risk 

assessment process: Hazard 

identification, dose-response, exposure 

assessment, and risk characterization. 

Response: EPA agrees that the 

purpose of this rule is to reduce 

visibility impairment caused by 

emissions of NOX from NGS. EPA has 

not conducted a health risk evaluation 

for this rulemaking that attempts to 

characterize or quantify a public health 

benefit. Because NOX is itself a criteria 

pollutant that affects public health and 

is also a precursor to ozone and fine 

particulate matter, which are also 

criteria pollutants that affect public 

health, we consider it reasonable to state 

that other benefits could exist. We also 

note that EPA does not agree that there 

are no health benefits from reductions 

in ozone and fine particulate matter 

below the level of the NAAQS. On the 

contrary, EPA’s practice of quantifying 

these benefits in regulatory impact 

assessments has been strongly 

supported by peer-reviewed science.75

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46527 

Mortality Technical Support Document.’’ Available 

from http://www.epa.gov/ttn/ecas/regdata/Benefits/ 

thresholdstsd.pdf. 

76See Proposed Rule at 78 FR 8280, 8284 and 

8285 (February 5, 2013). 

77 Id. at 8284. 

78See, e.g. WRAP PM Source Apportionment 

Technology (PSAT) results, available on WRAP 

Technical Support System, Source Apportionment 

Web page at http://vista.cira.colostate.edu/TSS/

Results/SA.aspx. 

79 Interagency Workgroup On Air Quality 

Modeling (IWAQM) Phase 2 Summary Report And 

Recommendations For Modeling Long Range 

Transport Impacts (EPA–454/R–98–019), EPA 

OAQPS, December 1998, http://www.epa.gov/

scram001/7thconf/calpuff/phase2.pdf. 

D. Comments on Factor 3—Existing 

Controls at NGS 

Comment: EPA failed to consider 

existing controls. 

Based on EPA’s statement in the 

Proposed Rule that the early installation 

of LNB/SOFA would not influence 

EPA’s BART determination and EPA’s 

use of a baseline scenario in the 

visibility modeling that did not include 

LNB/SOFA, the operator of the Kayenta 

Mine concluded that EPA failed to 

consider existing controls. 

Response: EPA disagrees with the 

assertion that we failed to consider 

existing controls. As described in our 

Proposed Rule and consistent with the 

BART Guidelines (directing BART 

determinations to conduct the fivefactor analysis generally using a 2001– 

2003 baseline) EPA evaluated LNB/

SOFA as a separate control technology 

in our BART analysis, as well as a 

technology that can be used in 

combination with post-combustion 

control technologies (i.e., SNCR and 

SCR).76 We also discussed the voluntary 

installation of LNB/SOFA in 2009–2011 

under Factor 3: Existing Controls at 

NGS.77

As discussed in section 8.5 of the 

RTC, EPA properly considered baseline 

emissions over the period 2001–2003 in 

our analysis of cost-effectiveness and 

anticipated visibility benefits of 

controls. Therefore, although we did not 

‘‘consider existing controls’’ in the exact 

manner preferred by the commenter, we 

appropriately considered the existence 

of LNB/SOFA in Factor 3 of our BART 

analysis. In addition, the ‘‘better than 

BART’’ framework that we used to 

assess and finalize BART alternatives 

explicitly accounts for the existing LNB/ 

SOFA. 

Comment: EPA should determine 

existing controls to be BART. 

Several commenters noted that NGS 

spent millions of dollars on LNB/SOFA 

to reduce NOX emissions to levels below 

the presumptive NOX emission levels in 

the BART Guidelines. 

One commenter stated that installing 

LNB/SOFA prior to a requirement to do 

so under the RHR or any other CAA 

requirement has resulted in greater total 

NOX emission reductions in the first 

regional haze planning period than 

would be required by the most stringent 

EPA BART determination. 

Response: EPA recognizes that the 

early and voluntary installation of LNB/ 

SOFA on one unit per year in 2009– 

2011 at NGS resulted in significant 

emission reductions from NGS. EPA 

agrees that the early installation of LNB/ 

SOFA on one unit per year was 

voluntary and resulted in significant 

NOX reductions in the first planning 

period for Regional Haze. However, 

based on our five-factor analysis, we 

have determined that SCR+LNB/SOFA 

is also cost-effective and would result in 

significant additional visibility 

improvement at a number of Class I 

areas. We therefore disagree that LNB/ 

SOFA should be determined BART for 

NGS. 

E. Comments on Factor 5—Anticipated 

Visibility Benefits 

Comment: General Comments on 

Visibility. 

Numerous commenters questioned 

the extent to which NGS impacts 

visibility at Class I areas or disputed 

EPA’s analysis that installation of SCR 

at NGS would improve visibility. Many 

commenters asserted that the haze is 

produced from emissions from other 

sources. 

Some commenters stated that the 

wind near and around the Grand 

Canyon blows predominantly west to 

east; thus, emissions from the NGS are 

pushed away from several Class I areas, 

not towards them. 

Response: We are aware of the studies 

cited by commenters purporting to show 

that controls on NGS would yield little 

visibility improvement, and we address 

them in section 7.0 of the RTC. We are 

also aware of work performed by the 

Western Regional Air Partnership 

(WRAP) suggesting that the relative 

contribution of nitrate from point 

sources to visibility impacts is relatively 

small.78 The CAA and RHR require that 

BART be installed on certain old, large 

stationary sources as part of the overall 

approach to improving visibility at Class 

I areas. No control at an individual 

source will be sufficient to meet the goal 

of remedying existing impairment of 

visibility in mandatory class I Federal 

areas which result from manmade air 

pollution, as set out in section 169A of 

the CAA. 

On the issue of wind direction, we 

note that the CALPUFF modeling uses 

three years of hourly meteorological 

input, which is based on meteorological 

modeling as well as observational data 

from stations throughout a large area. 

The input includes wind speed and 

direction, and would include the 

particular wind direction patterns noted 

by the commenter. The more 

sophisticated meteorological treatment 

in CALPUFF enables it to track the 

pollutant plume from NGS, including its 

twists and turns over multiple days. We 

consider this approach to adequately 

account for variability in winds noted 

by the commenter. 

Comment: EPA underestimated 

visibility benefits of SCR. 

One commenter stated that the 

visibility benefits of SCR are greater 

than those modeled by EPA because 

EPA underestimated SCR performance 

and because EPA overestimated the 

potential increase in sulfate emissions 

that may come with the addition of SCR 

controls by assuming an SO2 to SO3

conversion rate that is too high and 

using an erroneous value for the coal 

sulfur content. The commenter stated 

that its own modeling shows greater 

visibility improvement than 

demonstrated by EPA. 

Response: We disagree that EPA 

underestimated the visibility benefits of 

SCR and we note that the commenter’s 

assertion that the visibility benefits are 

even better would not change our 

proposed determination under Factor 5 

that the anticipated visibility benefits of 

SCR+LNB/SOFA are significant and 

support our proposed BART limit for 

NOX, achievable with SCR+LNB/SOFA. 

Please see the RTC for a detailed 

discussion of EPA’s responses to the 

commenter’s specific assertions. 

Comment: EPA overestimated 

visibility impact of NGS by using 

background ammonia concentrations 

that were too high. 

Several commenters argued that 

EPA’s assumed ammonia background 

concentration of 1 part per billion (ppb), 

the default value recommended by the 

Interagency Workgroup on Air Quality 

Modeling (IWAQM), is unrealistically 

high compared to measured values in 

the area, resulting in artificially high 

model projections of visibility impacts, 

particularly in the winter.79 The 

commenter noted that the use of a 

constant value of 1.0 ppb for 

background ammonia concentration 

fails to account for known variations in 

monthly or seasonal ammonia 

concentration. 

One commenter cited an analysis 

conducted on behalf of SRP by AECOM 

and Dr. Ivar Tombach. The commenter 

stated that the Tombach study 

compared modeled predictions of 

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80See RTC and references therein. 

81See e.g., SRP comments Appendix G, 

‘‘Measurements of Ambient Background Ammonia 

on the Colorado Plateau and Visibility Modeling 

Implications’’, Prepared by Salt River Project, 

Contributors: Ivar Tombach and Robert Paine, 

September 2010. Referred to here as ‘‘SRP 

monitoring report’’, or Tombach & Paine 2010. 

82See RTC and references therein. 

83SRP monitoring report, or Tombach & Paine 

2010, and SRP comments Appendix C. ‘‘Revised 

BART Analysis for the Navajo Generation Station 

Units 1–3’’ (January 2009) and Appendix I. 

‘‘Visibility Modeling Using Upgraded CALPUFF 

Model’’ (February 2011). 

84See RTC and references therein. 

85 Id. 

86See RTC and references therein. 

87See RTC and references therein. 

88See RTC and references therein. 

ammonium nitrates using both EPA’s 

and AECOM’s ammonia background 

concentrations to measured ammonia 

values, demonstrating that the EPA’s 

assumptions over-predict actual 

measured values by a factor of 10 or 

more in some cases. 

One commenter noted that when the 

IWAQM guidance was issued 14 years 

ago, CALPUFF did not have the 

capability of accommodating monthly 

ammonia background concentrations as 

it has since been updated to do. The 

commenter asserted that EPA’s reliance 

on a constant value is an outdated 

approach. 

Response: EPA has already 

considered and addressed the same 

arguments and data provided by 

commenters related to background 

ammonia concentrations in other 

rulemakings, including our final rule for 

Four Corners Power Plant.80 As 

summarized briefly below, EPA 

disagrees that our use of the IWAQM 

default background ammonia 

concentration for arid areas of 1 ppb 

was inappropriate. Please see the RTC 

for the full response to this comment. 

We have carefully reviewed the 

comments and concluded that, on 

balance, the evidence does not support 

using lower values for background 

ammonia concentrations, as argued by 

the commenters, in estimating the 

visibility impacts from NGS. Much of 

the existing measured data cited by the 

commenters is from other states and 

may not be representative for evaluating 

visibility impacts from NGS.81 Further, 

existing data sometimes represent 

ammonia alone rather than total 

ammonia and ammonium. Because 

ammonium represents part of the pool 

of ammonia that could be available to 

interact with the SO2 and NOX emitted 

from stationary sources, it should be 

accounted for in the value for 

background ammonia concentrations 

used in the model. In several of the 

research papers cited by commenters, 

the amount of measured ammonium is 

comparable to and at times much greater 

than the amount of ammonia.82

Measurements made by SRP closer to 

NGS over December 2009 to April 2010, 

which included ammonia and 

ammonium, showed that depending on 

time and location, typical ammonia 

concentrations ranged from 0.2 ppb to 

0.8 ppb and the concentration of total 

ammonia and ammonium ranged from 

0.6 to 1.2 ppb, which is considerably 

higher than the 0.2 ppb winter values 

used in SRP’s modeling.83 Although 

some of the ammonium may not be 

available to interact with pollutants 

from NGS, the sum of ammonia and 

ammonium provides an upper bound 

estimate of background ammonia 

concentrations, and represents a 

conservative estimate for modeling. 

We further note that there are 

measurements of gaseous ammonia 

alone that show concentrations close to 

or greater than the concentration of 1 

ppb, even in winter when ammonia 

concentrations are expected to be 

lowest. Winter measurements, 

representing 3-week averages, ranged 

from 1.1 ppb to 1.8 ppb at a monitor at 

the Farmington Airport in northwestern 

New Mexico.84 Measurements from the 

winters of 2011–2013 from the AMoN 

network ranged from 1.1 to 1.3 ppb for 

Farmington, and 0.7–0.9 ppb for 

Chiricahua, in southeastern Arizona.85

We further note that there is 

significant variability in the 

concentrations of ammonia measured at 

different times and places. Even the SRP 

monitoring report (Tombach & Paine, 

2010, cited above) describes a 

surprisingly high spatial variability in 

ammonia concentrations. Because of the 

variability and its unknown causes, the 

data collected for SRP did not lead to a 

clear picture of appropriate and 

representative background ammonia 

concentrations to use with CALPUFF. 

Finally, we note that using the 

background ammonia concentrations 

recommended by commenters does not 

change our conclusion under Factor 5 

because CALPUFF modeling of SCR 

shows substantial visibility benefits 

even using the alternative 

assumptions.86 Using a background 

ammonia concentration of 1 ppb 

ammonia, EPA modeled the greatest 

benefit from SCR+LNB/SOFA to be 5.4 

deciviews at Capitol Reef NP, and 

modeled a visibility benefit exceeding 1 

to 2 deciviews at ten additional Class I 

areas. Using the ammonia concentration 

recommended by some commenters 

(ranging from 0.2 ppb in winter to 1.0 

ppb in summer), EPA modeled the 

greatest benefit of SCR to be 2.3 dv, and 

modeled a visibility benefit exceeding 1 

deciview at nine Class I areas, with 

three of these nine areas having a 

benefit of approximately two deciviews. 

Even assuming a lower ammonia 

concentration, the modeling 

demonstrates that the installation of 

SCR+LNB/SOFA at NGS would have a 

significant beneficial impact on 

visibility at a number of Class I areas. 

Our conclusion as to the appropriate 

BART Benchmark for NGS would not 

accordingly change. 

Comment: EPA should have used an 

updated version of CALPUFF. 

Several commenters asserted that EPA 

erred in using CALPUFF version 5.8 in 

its modeling rather than the more recent 

CALPUFF version 6.42, released by 

TRC. One commenter argued that 

CALPUFF version 6.42 predicts lower 

visibility benefits than version 5.8. 

Response: We disagree with the 

commenters that a new CALPUFF 

version should be used for the BART 

determination. We relied on version 5.8 

of CALPUFF because it is the version 

approved by EPA through a public 

notice and comment rulemaking, in 

accordance with the Guideline on Air 

Quality Models (‘‘GAQM’’, 40 CFR part 

51, Appendix W, section 6.2.1.e).87

CALPUFF version 6.4 is not approved 

by EPA for regulatory purposes, and we 

do not agree that the changes made to 

this most recent version of CALPUFF 

were simple model updates to address 

bugs. A full evaluation of a new model 

such as CALPUFF version 6.4 is needed 

before it should be used for regulatory 

purposes as errors that are not 

immediately apparent can be introduced 

along with new model features. 

Comment: Closure of Mohave Project 

did not improve visibility and shows 

CALPUFF is unreliable. 

One commenter discussed the 

findings of an analysis conducted after 

the closure of the Mohave Power Project 

(MPP) (a 1,580 MW coal-fired power 

plant) to evaluate whether the closure 

had resulted in improved visibility in 

Grand Canyon National Park.88 The 

commenter indicated that although 

CALPUFF version 5.8 modeling 

predicted that the plant had a 

significant impact on visibility in the 

Grand Canyon, this study concluded 

that there was ‘‘virtually no evidence 

that the MPP closure improved visibility 

in the Grand Canyon.’’ The commenter 

asserted that this study raises questions 

about the reliability of CALPUFF. 

Response: We disagree that the 

Terhorst & Berkman (T&B) study cited 

by the commenters raises questions 

about CALPUFF’s reliability. The 

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89W.H. White, R.J. Farber, W.C. Malm, M. Nuttall, 

M.L. Pitchford, B.A. Schichtel, Comment on ‘‘Effect 

of coal-fired power generation on visibility in a 

nearby national park (Terhorst and Berkman, 

2010)’’, Atmospheric Environment 55 (2012) 173– 

178. doi:10.1016/j.atmosenv.2012.02.076. Also 

available at: http://www.dri.edu/marcpitchford?showall=&start=2. 

90EPA considered and rejected comments on the 

proposed BART Guidelines that visibility impacts 

should be evaluated relative to current degraded 

visibility conditions and concluded that ‘‘[u]sing 

existing conditions as the baseline for single source 

visibility impact determinations would create the 

following paradox: The dirtier the existing air, the 

less likely it would be that any control is required.’’ 

(70 FR 39104 at 39124, July 6, 2005). 

91EPA’s Environmental Appeals Board has 

recognized that PSD emission limits must be set to 

allow fluctuations in operations, stating: ‘‘To 

account for these possibilities, a permitting 

authority must be allowed a certain degree of 

discretion to set the emissions limitation at a level 

that does not necessarily reflect the highest possible 

control efficiency, but will allow the permittee to 

achieve compliance consistently.’’ In Re Masonite 

Corporation, 5 E.A.D. 551, 560–61 (1994). 

92See RTC and references therein. 

93The response included in this Final Rule is 

abbreviated and excludes the graphs and tables EPA 

generated to support our response. For additional 

detail, please see the RTC. 

conclusion in the T&B study on the 

effect of MPP closure is actually similar 

to that from earlier analyses, which also 

predicted improvements less than the 

human perceptibility threshold of 1 dv. 

A response to the T&B study written by 

White et al., stated that the T&B analysis 

is ‘‘misleadingly presented as 

discrediting previous studies and their 

interpretation by regulators. In reality 

the T&B analysis validates a consensus 

on MPP’s visibility impact that was 

established years before its closure.’’ 89

White et al., explicitly addressed the 

purported disagreement between the 

T&B methodology and results from 

CALPUFF, pointing out that the 

comparison was flawed in several ways. 

First, the ambient data relied upon by 

T&B are collected only every third day; 

this results in an insufficient number of 

days for a valid statistical comparison to 

the 98th percentile results reported from 

CALPUFF. Another important flaw is 

that when T&B translated visibility 

extinction into deciviews, they used 

recent polluted conditions as the 

background for comparison, whereas the 

BART Guidelines and the CALPUFF 

results use natural conditions as 

background.90 When the T&B results are 

computed using natural background, 

they are substantially larger, and 

generally in agreement with CALPUFF 

results. 

F. Comments on BART Determination 

for NOX

Comment: BART limit for NGS should 

be 0.04 lb/MMBtu. 

One commenter argued that the final 

BART emission limit should be more 

stringent and no higher than 0.04 lb/

MMBtu. The comment noted that 

permitting authorities have required 

lower NOX limits than 0.055 lb/MMBtu 

in recent BACT determinations based on 

SCR in combination with combustion 

controls. 

Response: EPA disagrees with the 

commenter that the BART Benchmark 

for NGS should be 0.04 lb/MMBtu. We 

note that the commenter has not 

provided any specific information to 

show that NGS could demonstrate 

continuous compliance with an 

emission limit of 0.04 lb/MMBtu. The 

commenter generally argued that SCR 

systems are typically designed to 

achieve 90 percent removal. EPA notes 

that although an SCR system can be 

designed to a specific target, the design 

target is typically not equivalent to the 

actual emission limit.91 EPA proposed a 

limit of 0.055 lb/MMBtu achievable 

with SCR+LNB/SOFA, and using a 

baseline emission rate of 0.35 lb/

MMBtu, this represents a removal 

efficiency of 84 percent.92 However, as 

noted elsewhere in the RTC, the limit of 

0.055 lb/MMBtu, which accommodates 

startup, shutdown, and low-load 

operation, is based on a design target of 

0.03 lb/MMBtu. This represents a design 

target removal efficiency of 91 percent 

for SCR+LNB/SOFA (from a baseline of 

0.35 lb/MMBtu), or 88 percent for SCR 

alone (i.e., from 0.24 lb/MMBtu). 

EPA disagrees with the commenter’s 

assertion that emission limits associated 

with BART must meet BACT or the 

lowest emission rate ever achieved with 

that technology at any coal-fired power 

plant. The BART Guidelines state that: 

‘‘[i]n assessing the capability of the 

control alternative, latitude exists to 

consider special circumstances 

pertinent to the specific source under 

review, or regarding the prior 

application of the control alternative’’, 

(70 FR 39166) and that ‘‘[t]o complete 

the BART process, you must establish 

enforceable emission limits that reflect 

the BART requirements . . .’’ (70 FR 

39172). The five-factor BART analysis 

described in the Guidelines is a case-bycase analysis that considers site specific 

factors in assessing the best technology 

for continuous emission controls. After 

a technology is determined as BART, 

the BART Guidelines require 

establishment of an emission limit that 

reflects the BART requirements, but 

does not specify that the emission limit 

must represent the maximum level of 

control achieved by the technology 

selected as BART. For these reasons, 

EPA is not using the lower limit 

recommended by the commenter in 

setting the BART Benchmark. 

Comment: BART limit for NGS should 

be in the range of 0.07–0.08 lb/MMBtu. 

Several commenters asserted that the 

NOX emission limit EPA proposed for 

NGS is unachievable. One commenter 

noted that the averaging period for the 

proposed limit of 0.055 lb/MMBtu 

includes periods when the SCR is 

unable to operate such as startup, 

shutdown, and periods of load-cycling. 

The commenter made the following 

arguments: (1) The S&L analysis 

submitted by the commenter shows that 

the proposed emission limit is 

unachievable on a continuous basis; (2) 

the NOX emissions achieved in other 

SCR retrofit situations do not justify the 

proposed emission limit. 

Response: EPA disagrees with the 

commenter that the limit used in setting 

the BART Benchmark for NGS should 

be higher than our proposed limit of 

0.055 lb/MMBtu, in the range of 0.07 to 

0.08 lb/MMBtu.93

The S&L report generally argues that 

because the emission limit is 

established based on a 30–BOD average 

basis, the proposed emission limit of 

0.055 lb/MMBtu is not consistently 

achievable at NGS. The S&L analysis is 

based on a design target of 0.03 lb/

MMBtu and suggests an emission limit 

in the range of 0.07–0.08 lb/MMBtu 

would be required to accommodate 

periods of load-cycling operation, 

startups, and shutdowns. S&L is 

recommending a limit that is 2.3 to 2.7 

times higher than the design target, or 

a compliance margin of 133 to 167 

percent. 

The S&L report discusses the 

temperature limitations associated with 

SCR and explains that at temperatures 

below a specific minimum operating 

temperature, a component of the SCR 

system (i.e., ammonia injection) must 

cease to prevent ammonium salt 

formation on the catalyst. S&L asserts 

that a minimum operating temperature 

of 580 °F is typical for retrofit SCR 

control systems installed on coal-fired 

electric generating units with similar 

coal sulfur content and states that this 

temperature corresponds with a gross 

load of approximately 650 MW (650 

gross MW, or MWg). S&L further 

assumes that SRP will likely modify the 

units to increase flue gas temperatures 

at lower operating loads by installing 

one of several options for low load 

temperature control. In their analysis, 

S&L assumes the low load temperature 

control would be achieved with a waterside bypass (to allow water to bypass 

the economizer tube bundles during 

low-load operation). The S&L report 

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94See RTC and references therein. 95See RTC and references therein. 

96See, for example, publication from the U.S. 

Geological Survey, figure PQ–4 and Table PQ–1, 

available at http://pubs.usgs.gov/pp/p1625a/

Chapters/PQ.pdf. 

97 Id. 

states ‘‘[b]ased on a preliminary review 

of the available systems, a water-side 

bypass system should be capable of 

increasing the temperature of the bulk 

flue gas by approximately 25 °F to 65 °F 

during low-load operation. For this 

evaluation, a low-load temperature 

control system capable of achieving a 

temperature increase of 65 °F during 

low-load operations was assumed for 

modeling purposes.’’ S&L further 

estimates that this would correspond to 

a minimum gross load of 450 MWg for 

the SCR to operate, or operation at 55 

percent capacity. 

Using the assumption that the SCR 

would not operate at loads below 450 

MWg, S&L used 2012 operations data at 

NGS to estimate emission rates at NGS 

assuming a design target of 0.03 lb/

MMBtu with actual steady-state 

operations achieving 0.04 lb/MMBtu. 

S&L modeled eighteen different 

operating scenarios and identified seven 

scenarios, which included periods of 

low load cycling along with unit startup 

and shutdowns, that resulted in the 

maximum 30–BOD average for each unit 

and facility-wide, that exceeded 0.055 

lb/MMBtu. The highest 30–BOD average 

S&L modeled was 0.077 lb/MMBtu for 

Unit 2, achieved under 3 different 

operating scenarios involving low-load 

cycling. 

SRP and S&L did not provide the 

underlying data used in the S&L 

analysis. Therefore, EPA evaluated the 

S&L report by reviewing emissions data 

from the EPA Air Markets Program Data 

(AMPD) for multiple years, as well as 

emissions data from other facilities that 

were constructed or retrofit with SCR. 

EPA sought to understand 2012 

operations at NGS within the context of 

longer term operational trends at the 

facility, as well as understand the 

minimum operating load assumed by 

S&L for NGS within the context of 

minimum operating loads at other 

facilities with SCR. 

EPA evaluated the reported hourly 

gross load operating data for Units 1–3 

at NGS for the years 2001, 2003, 2010, 

2011, 2012, and 2013.94 Emission data 

from AMPD show that NGS, and in 

particular, Unit 2, spent a higher 

percentage of operating hours at gross 

loads below 450 MWg in 2012 

compared to other years. The 2012 gross 

load profiles for Unit 2 (as well as Units 

1 and 3) are characteristic of loadcycling units, with significant periods of 

time below the purported SCR 

minimum operating load of 450 MWg, 

particularly in the spring. Please see the 

RTC for more detail. In 2010, Unit 2 also 

operated for significant periods of time 

at loads below 450 MWg. However, 

these periods in 2010 occurred 

following the major outage on Unit 2 

(following installation of LNB/SOFA on 

that unit). Although Units 1–3 at NGS 

did appear to operate as load-cycling 

units and operated below 450 MWg for 

significant periods of time in 2012, this 

type of operation does not appear to be 

characteristic of typical operation at 

NGS, based on our evaluation of 

previous years, as well as 2013. 

Based on the gross load operating 

profiles for six years, EPA estimated the 

rolling 30–BOD averages for each BOD 

to determine whether the operating 

profiles (which included actual startup, 

shutdown, and load-cycling in each 

year) would result in 30–BOD averages 

that would exceed 0.055 lb/MMBtu. 

Based on our analysis, EPA projected 

the highest 30–BOD average to be 0.079 

lb/MMBtu (Unit 2 in 2010). Using 2012 

data, representative of load-cycling 

operation, EPA projected the highest 

30–BOD average to also occur on Unit 

2 (0.075 lb/MMBtu). Similarly, S&L 

projected the highest 30–BOD average in 

2012 was from Unit 2, at 0.077 lb/

MMBtu. Therefore, although the 

scenarios modeled by S&L and EPA 

were not identical, the highest 30–BOD 

averages projected by EPA and S&L, 

using similar starting assumptions, were 

comparable. Our analysis, of projected 

SCR performance, which included 

emission and operating profiles of 

actual startup and shutdown events, and 

load-cycling in various years, showed 

that Unit 3 was not projected to exceed 

0.055 lb/MMBtu in any of the evaluated 

years, and that there were several years 

within these six selected years that 

Units 1 and 2 would also not exceed 

0.055 lb/MMBtu. 

The analysis of projected 30–BOD 

average emission rates assumes that 

S&L’s value of 450 MWg (or 55 percent 

capacity) for the minimum operating 

load to operate SCR at NGS is correct. 

EPA notes that 450 MWg was a value 

that S&L assumed based on preliminary 

analysis of available low load 

temperature control systems. SRP 

submitted a similar S&L analysis to EPA 

for Units 1 and 3 at Coronado 

Generating Station (CGS).95 Units 1 and 

2 at CGS are 430 MWg Riley-Turbo units 

that typically operate as load-cycling 

units. CGS burns low-sulfur coal from 

the Powder River Basin (PRB coal). With 

the application of low-load temperature 

controls on these units, S&L’s analysis 

suggests that the minimum operation 

load for SCR on Units 1 and 2 at CGS 

would be 138 MWg (or 32 percent 

capacity). This is significantly lower 

than the 55 percent capacity S&L 

assumed for NGS. S&L stated that the 

coal sulfur content will affect the 

minimum operating load for SCR. NGS 

does not burn PRB coal; however, NGS 

does burn low-sulfur coal from the 

Kayenta Mine. AECOM, SRP’s 

consultant for visibility modeling, 

reported the maximum sulfur content of 

the coal as 0.593 percent based on daily 

data for the 2001–2003 period. For 

comparison, various sources reference 

PRB coal as generally low-sulfur coal 

with a sulfur content of less than 1 

percent, or a mean of 0.5 percent.96 In 

contrast, high sulfur coal is typically 

above 3 percent.97

EPA evaluated emission data of eight 

well-performing units burning PRB coal 

and generated empirical estimates for 

minimum operating loads and capacity 

requirements for SCR operation at those 

facilities. Based on this analysis (see 

RTC for further detail), EPA estimated 

capacity requirements for SCR operation 

that ranged from 35 percent to 46 

percent, with an average value of 40 

percent. Using the average (40 percent) 

and the maximum (46 percent) capacity 

requirement to operate SCR, EPA 

projected that NGS would meet a limit 

of 0.055 lb/MMBtu (on a 30–BOD 

average) for all but 3 cases (i.e., Units 1 

and 2 in 2012, and Unit 2 in 2010) 

under the 46 percent capacity 

requirement. Under the 40 percent 

capacity requirement to run SCR, Units 

1 and 2 in 2012 would remain below 

0.055 lb/MMBtu and for Unit 2 in 2012 

the highest 30–BOD average was 

projected to be exactly 0.055 lb/MMBtu. 

Operation of Unit 2 in 2010 was not 

typical of normal operation. Please see 

RTC for more detail on this analysis. 

The S&L report concludes that even 

with a design target for SCR of 0.03 lb/ 

MMBtu, a limit of 0.07–0.08 lb/MMBtu 

is required to accommodate periods of 

startup, shutdown, and load-cycling 

operation. EPA agrees that load-cycling 

operation appears to be an important 

factor; however, EPA concludes that the 

critical S&L assumption, that the units 

at NGS must operate at approximately 

55 percent capacity in order for the SCR 

to operate, was not sufficiently 

supported and was acknowledged by 

S&L to be an assumption based on a 

preliminary review of available lowload temperature control systems. EPA 

also notes that in the S&L revised 2013 

cost analysis, S&L included costs for hot 

water recirculation systems which 

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98See page 1–2 of the Sargent and Lundy report 

prepared for SRP, dated January 2, 2014, included 

as Appendix U to the SRP comment letter in the 

docket for this rulemaking. 

99See 77 FR 14604, 14608–14610 (March 12, 

2012) for a detailed discussion of the presumptive 

limits. 

100See May 2012 Brattle Group document, page 

12 and page 17, in the docket for this rule. 

101See EPA 2002 Multipollutant Strategies 

document, page 22, in the docket for this rule. 

102See page 17 of the EarthJustice comment letter, 

in the docket for this rule. 

103See Final BART FIP for Four Corners Power 

Plant an compliance dates under the BART 

Alternative at 77 FR 51620 at 51648 (August 24, 

2012) and Final Regional Haze FIP for Arizona 

(phase 1) at 77 FR 72512 at 72578 (December 5, 

2012). 

104See section 169A of the CAA (sections 

169A(b)(2)(A) and (g)(4)). 

‘‘maintains SCR in operation at all plant 

operating loads’’ (emphasis added).98

In summary, EPA is finalizing a BART 

Benchmark based on an emission limit 

for NGS of 0.055 lb/MMBtu on a rolling 

30–BOD basis. In determining the 

achievability of this limit, EPA has 

conducted an analysis that considers 

actual periods of startup, shutdown, and 

low-load cycling. Based on the 

understanding that S&L would design 

the SCR system at NGS to a design target 

of 0.03 lb/MMBtu, the BART limit of 

0.055 lb/MMBtu represents an adequate 

compliance margin to accommodate 

periods of startup, shutdown, and loadcycling operation. 

Comment: Presumptive Limit for NOX. 

Several commenters noted that with 

existing LNB/SOFA controls, NGS emits 

NOX at rates below the presumptive 

limit of 0.28 lb/MMBtu established by 

the EPA in the BART Guidelines. A 

commenter stated that to properly 

justify departure from the presumptive 

BART limit, EPA must evaluate the 

impacts of the presumptive BART limit 

in its five-factor analysis. 

Response: EPA disagrees with the 

comment that installation of LNB/SOFA 

at NGS should satisfy BART simply 

because it meets the presumptive limit 

for NOX of 0.28 lb/MMBtu in the BART 

Guidelines for tangential-fired boilers 

burning bituminous coal. Presumptive 

BART limits, and the corresponding 

technology upon which those limits are 

based, do not preclude states or EPA 

from setting limits that differ from those 

presumptions based on case-specific 

consideration of the relevant BART 

factors. The presumptive limits 

generally represent a minimum level of 

control for BART for various types of 

power plants, based on EPA’s 

assessment of the typical costs of 

controls and likely visibility benefits.99

EPA further disagrees with the assertion 

that we did not evaluate the impacts of 

the presumptive BART limit in our fivefactor analysis. The presumptive BART 

limit of 0.28 lb/MMBtu is based on the 

installation and operation of modern 

combustion controls. EPA evaluated 

LNB/SOFA (at a limit of 0.24 lb/MMBtu, 

which is each unit’s existing permitted 

NOX limit for operation with LNB/

SOFA) in the five-factor analysis on 

which our proposed rule was based. 

Please see our RTC for a detailed 

discussion. 

Comment: Install SCR within 3.5 

years. 

One commenter stated that the CAA 

requirement for BART to be installed 

‘‘as expeditiously as practicable’’ 

requires installation and full 

implementation of SCR on all three 

units at NGS within 3.5 years rather 

than five years. The commenter stated 

that EPA provided no site-specific 

factors at NGS that would require a 

longer-than-average installation time for 

SCR (particularly in light of the fact that 

it appears contractors in the region will 

not be overwhelmed). 

Response: EPA disagrees with the 

commenter that a 3.5-year compliance 

deadline for the installation of SCR 

would be practicable for NGS. EPA 

agrees that there are numerous sources 

of information, including EPA’s 

response to comments on its BART 

determination for SJGS, to suggest that 

on average, the time required to design 

and construct an SCR system can range 

from 37 to 43 months. The commenter 

also cites EPA documents suggesting 

that it generally takes 21 months to 

design, install, and test one SCR unit, 

and 35 months for SCR installation at 

power plants with multiple SCR units, 

and another publication that suggests 

that SCR can be installed in less than 

five years (i.e., document from The 

Brattle Group). Our RTC contains a 

detailed discussion of our conclusion 

that the Brattle Group estimate of 47 

months (nearly 4 years) applies to one 

unit, not multiple units at one 

facility.100

In addition, although EPA cited one 

facility where the retrofit of seven units 

required 35 months, EPA also stated 

‘‘ideally, longer than 35 months would 

allow for all the retrofits to occur over 

a period of several years so that facility 

owners can properly plan outages and 

suppliers can properly plan for resource 

availability.’’ 101

The commenter also states that ‘‘it 

appears contractors in the region will 

not be overwhelmed’’ to justify why 

installation time for SCR should not be 

longer than average.102 We note that 

‘‘installation time’’ is one part of 

compliance, and that EPA must also 

consider time for design, procurement, 

and permitting. We also note that the 

commenter did not provide any support 

for its statement that contractors in the 

region will not be overwhelmed. We 

note that several EGUs in the southwest 

have compliance dates for the 

installation of SCR around 2018.103

Therefore, EPA anticipates that leading 

up to 2018, numerous coal-fired EGUs 

in the region will be retrofited with 

post-combustion controls. 

In taking action to finalize a BART 

Benchmark, EPA is retaining the five 

year compliance period as proposed. 

Because BART compliance at NGS 

involves the design, procurement, and 

installation of SCR on three units and 

upcoming ownership changes at NGS as 

discussed in our proposed rule, EPA is 

determining that a five-year BART 

compliance timeframe at NGS is as 

expeditious as practicable. This is 

within the range cited by the 

commenters and the facility operator 

(i.e., average of 21 to 47 months per 

unit, or 35 months to 67 months for 

multiple units at one facility) and is 

consistent with the CAA which requires 

BART compliance as expeditiously as 

practicable but no later than five years 

following the effective date of the final 

rule.104

G. Comments on BART for PM 

Comment: Support/opposition for 

finding not to establish PM BART. 

Several commenters supported EPA’s 

statement in the Proposed Rule that 

‘‘[b]ecause emissions of PM are well 

controlled at NGS through federally 

enforceable limits, EPA is not proposing 

that it is ‘‘necessary or appropriate’’ 

under the TAR to determine BART for 

PM emissions at NGS.’’ 

Some commenters noted that 

implementation of the Mercury and Air 

Toxics Standards (MATS) in the near 

future will establish an additional 

federally enforceable limit for PM of 

0.03 lb/MMBtu. The commenters added 

that the BART Guidelines provide that 

one can generally rely on MACT 

standards for purposes of BART. 

In contrast, two commenters asserted 

that EPA was incorrect to determine that 

it need not evaluate BART for control of 

PM at NGS. The commenter asserts that 

the existing PM limit of 0.06 lb/MMBtu 

was not based on a BART analysis and 

does not reflect a well-controlled PM 

emission rate for a coal-fired EGU. 

One commenter asserted that the 

electrostatic precipitators (ESPs) at NGS 

do not represent the best system of 

control for PM. The commenter believes 

that EPA’s determination is inconsistent 

with recent BART and BACT 

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105 78 FR 8279 (February 5, 2013). 

106EPA initially codified the requirements for 

NGS to meet an SO2 emission limit in an existing 

FIP for the State of Arizona. See 40 CFR 52.145. 

After promulgation of the TAR, EPA moved the 

NGS SO2 FIP to 40 CFR 49.5513 

107See 40 CFR 51.308(e)(2); CAWCD v. EPA, 990 

F.2d 1531 (9th Cir. 1993); CEED v. EPA, 398 F.3d 

653 (D.C. Cir. 2005); UARG v. EPA, 471 F.3d 1333 

(D.C. Cir. 2006). 

108See CAA section 169A(1)(a). 

109See 79 FR 12944, 12950 (March 7, 2014). 

‘‘While it is true that the Regional Haze Rule and 

BART Guidelines do not contemplate unit 

retirements as a potential BART option, neither rule 

prohibits states or EPA from considering a 

shutdown as part of a BART determination if the 

strategy is proposed by the owner of a BARTeligible source.’’ 

determinations for coal-fired utility 

boilers that set emissions limits for PM 

of 0.015 lb/MMBtu or lower based on 

the use of fabric filter baghouses. The 

commenter concluded that EPA should 

revise its determination and complete a 

BART analysis for PM that includes 

evaluation of fabric filter baghouses. 

Response: EPA agrees with the 

comment that it is not necessary or 

appropriate to require BART for PM 

emissions from NGS at this time. As we 

stated in our proposed rule: ‘‘Emissions 

of PM and SO2 are controlled by hotside electrostatic precipitators (HS– 

ESPs) and wet scrubbers, 

respectively.’’ 105 Because NGS will be 

required to comply with the PM 

emissions limits in the MATS rule, EPA 

continues to find that it is not necessary 

or appropriate at this time to promulgate 

a BART emission limit for PM from 

NGS. EPA is not determining that the 

existing PM emission limit for NGS is 

BART. Instead, it is EPA’s position that 

it is not necessary or appropriate under 

our discretionary authority under the 

TAR, promulgated at 40 CFR 49.11, to 

conduct a BART determination for PM 

emissions because they are currently 

well-controlled and will be further 

reduced by compliance with the 0.03 lb/ 

MMBtu emission limit in the MATS 

rule. 

One commenter asserted that EPA 

should require fabric filter baghouses as 

BART for PM. EPA cannot agree or 

disagree that baghouses would be 

required as BART for PM because, as 

described above, we have determined 

that it is not necessary or appropriate at 

this time to conduct a BART 

determination for PM at NGS. 

H. Comments on BART for SO2

Comment: Support for finding that 

Reasonable Progress is met for SO2.

Several commenters noted that EPA 

recognized in the Proposed Rule that the 

emission limits EPA established for SO2

in 1991 were determined to achieve 

greater reasonable progress than would 

BART. Several commenters agreed that 

no additional emission limits or 

controls should be required as a result 

of BART for SO2 emissions. One 

commenter noted that the existing SO2

limit at NGS is more stringent than the 

BART Guidelines’ presumptive SO2

limit. 

Response: EPA agrees with these 

comments. As EPA stated in our 

proposal in February 2013, the SO2

emissions limit established in EPA’s 

1991 SO2 FIP was determined to be 

better than BART under the visibility 

regulations addressing reasonably 

attributable visibility impairment. 

Specifically, EPA determined that 

promulgating a SO2 emission limit of 

0.10 lb/MMBtu on an annual average 

basis would result in greater cumulative 

SO2 emissions reductions and visibility 

improvement over time than would the 

SO2 BART limit that EPA had proposed 

for NGS. NGS installed a wet flue gas 

desulfurization system to reduce SO2

emissions on each of its boilers in 1997– 

1999.106

I. Comments on EPA’s BART Alternative 

Comment: Support for EPA’s 

authority for ‘‘better than BART.’’ 

Several commenters discussed and 

supported EPA’s policy and legal 

rationale for its discretion to approve 

‘‘better than BART’’ alternatives and to 

provide an extended period for 

implementation of such an alternative at 

NGS. One commenter also opined that 

the 5-year compliance period for BART 

that is defined in section 169A(g)(4) of 

the CAA applies by its terms only to: (1) 

SIPs, by providing that the BART 

compliance date shall be no later than 

‘‘five years after the date of approval of 

a plan revision under this section’’; and 

(2) FIPs promulgated under CAA section 

110(c), by providing that the BART 

compliance date under any such FIP 

shall be no later than ‘‘five years after 

. . . the date of promulgation of such 

a plan revision in the case of action by 

the Administrator under section 

110(c).’’ The commenter concluded that 

because the FIP for NGS is not 

promulgated under section 110(c) of the 

CAA, the 5-year timeframe for BART 

does not apply to NGS. 

Response: EPA agrees with the 

comment in support of our action to 

find that the TWG Alternative meets the 

framework established in our Proposed 

Rule. EPA agrees that we have the legal 

authority under the CAA and RHR to 

implement a ‘‘better than BART’’ 

alternative.107 EPA agrees that we have 

the authority under the CAA and the 

TAR to extend the compliance date that 

will apply to the ‘‘better than BART’’ 

alternative pursuant to CAA Section 

301(d)(4) and 40 CFR 49.11(a), as 

discussed in detail below. 

We also note that regardless of 

whether the commenter is correct that 

the CAA does not require compliance 

with the BART requirements within five 

years for sources subject to a FIP in 

Indian country, we consider five years 

to be a reasonable timeframe for the 

installation and operation of SCR at 

NGS. To the extent the commenter is 

correct that the timing provisions of 

section 169A(g)(4) are outside the scope 

of EPA’s action to implement a FIP in 

Indian country under section 301 and 

the TAR, this further supports EPA’s 

determination that extending the 

compliance deadline beyond 2018 for a 

BART alternative at NGS is appropriate. 

EPA also agrees with the comment 

that approving the TWG Alternative for 

NGS will not compromise the ultimate 

goal of the RHR based on progress 

toward eliminating human-caused 

visibility impairment in Class I areas by 

2064.108 The TWG Agreement provides 

that NGS will cease conventional coalfired generation in 2044. Because the 

TWG Agreement included this 

provision, we are including a provision 

in the Final Rule that requires the 

operator of NGS to cease conventional 

coal-fired generation by December 22, 

2044.109 The TWG Agreement further 

states that the Navajo Nation may elect 

to operate NGS after December 22, 2044 

consistent with EPA approval. EPA is 

not including this provision in the 

regulatory requirements at 

§ 49.5513(j)(3)(iii); however, EPA 

expects that NGS would be substantially 

modified if the Navajo Nation were to 

elect to continue operation of the 

facility after NGS ceases conventional 

coal-fired generation in 2044, and that 

NGS would then need to meet all 

applicable regulatory and permitting 

requirements in existence at that time. 

In addition, any power generating units 

that may be built to replace NGS would 

also be subject to environmental review 

and air permitting requirements. 

Comment: General opposition to 

EPA’s ‘‘better than BART’’ 

determinations. 

One commenter stated that EPA may 

approve an alternative to BART only 

under certain limited circumstances, 

with the fundamental legal requirement 

being a demonstration that the 

alternative will ‘‘achieve greater 

reasonable progress toward natural 

visibility conditions’’ as supported by 

the clear weight of evidence. The 

commenter indicated that there are two 

ways EPA can make such a 

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110 In providing states with the flexibility to adopt 

alternative measures in lieu of BART, EPA assumed 

that under the BART alternative provisions, states 

would most likely adopt a trading program rather 

source specific BART controls. See, e.g., 40 CFR 

308(e) (a regional haze SIP must contain BART 

limits unless the State demonstrates that ‘‘an 

emissions trading program or other alternative will 

achieve greater reasonable progress. . .’’). The 

geographic distribution of emissions under a 

trading program is unlikely to be similar to that 

under source-specific BART. In contrast, the 

geographic distribution of emissions under a ‘‘better 

than BART’’ alternative that applies only to the 

BART source in question would be similar. 

111 70 FR 39136. 

112Although the commenter argues that visibility 

modeling is required to demonstrate that the TWG 

Alternative makes greater reasonable progress, the 

commenter notes only in passing the second test set 

out in the regulations at 40 CFR 51.308(e)(3) 

governing situations where BART and a BART 

alternative will result in dissimilar distributions of 

emissions. In such situations, greater reasonable 

progress may be shown if visibility modeling shows 

that (i) visibility does not decline in any Class I 

area, and (ii) there is an overall improvement in 

visibility by comparing the average differences 

between BART and the alternative over all affected 

Class I areas. Even absent visibility modeling, it 

seems clear that the TWG Alternative, which 

requires NGS to reduce emissions from current 

levels, will not cause visibility to decline in any 

Class I area. Visibility modeling done by EPA in 

response to comments regarding the limited 

benefits of SO2 and PM reductions suggests that the 

TWG Alternative also passes the second half of this 

test. As explained in the RTC, EPA modeled the 

visibility impacts of TWG Alternatives A1, A2, and 

A3 (the operating scenarios that include reductions 

in alternative pollutants). See RTC for further 

discussion. This modeling shows that the 

cumulative visibility benefits of the TWG 

Alternative outweigh those associated with BART. 

Although we have not modeled the visibility 

impacts of Alternative B, compliance with the 

2009–2044 and 2009–2029 NOX Caps will require 

NGS to achieve emission reductions similar to those 

required under Alternative A1 because the 2009– 

2029 NOX Cap is based on emissions that would be 

expected to occur under Alternative A1 (closure of 

one unit in 2019) and the 2009–2044 NOX Cap 

applies to all alternatives under the TWG 

Alternative. 

113 40 CFR 51.308(e)(2)(iii). 

114 78 FR 8288. 

demonstration: (1) Showing that the 

distribution of emissions is substantially 

similar under BART and the alternative 

measure, and that the alternative 

measure provides greater emissions 

reductions; or (2) performing modeling 

to demonstrate that visibility does not 

decline in any affected Class I area and 

there is an overall improvement in 

visibility. The commenter stated that the 

EPA may not use the first prong of the 

above test because the TWG Alternative 

distributes emissions over time 

differently than BART. Because the 

TWG Alternative also results in 

reductions of SO2 and PM, the 

commenter states that the pollutants 

reduced are also distributed differently. 

The commenter added that a BART 

alternative must ensure that all 

necessary emission reductions occur in 

the first planning period, which ends in 

2018, and that any emission reductions 

resulting from the alternative measure 

must be surplus to reductions required 

under other provisions of the CAA. 

Response: EPA disagrees with the 

commenter’s statement that the TWG 

Alternative fails to demonstrate that it 

will ‘‘achieve greater reasonable 

progress toward natural visibility 

conditions.’’ As explained below, we 

disagree with the various comments 

underlying the argument that our 

framework for analyzing the TWG 

Alternative is flawed. 

EPA appropriately focused on a 

comparison of the emissions reductions 

from BART and the TWG Alternative, 

rather than using visibility modeling to 

compare the two approaches. As the 

commenter noted, EPA’s regulations 

provide a specific two-pronged test that 

may be used to demonstrate that a 

BART alternative achieves greater 

reasonable progress. In this rulemaking, 

EPA has applied the first prong of that 

test to demonstrate that the TWG 

Alternative provides for greater 

reasonable progress. The first prong of 

the test, set out in 40 CFR 51.308(e), 

states that if the distribution of 

emissions is not substantially different 

under BART and the alternative, and 

‘‘the alternative measure results in 

greater emission reductions,’’ the 

alternative may be deemed to achieve 

greater reasonable progress. Because 

both BART and the TWG Alternative 

apply to the same source the geographic 

distribution of emissions is similar.110

EPA therefore applied this test to 

determine whether the TWG Alternative 

provided for greater reasonable progress, 

taking into account total NOX emissions 

over the 2009 to 2044 period from both 

BART and the TWG Alternative. 

The commenter argues, however, that 

the emissions must be temporally 

similar in order for this test to apply. 

When EPA added § 51.308(e)(3) to the 

regional haze regulations in 2005, 

however, we made clear that EPA 

intended this test to apply where the 

geographic distribution of emissions 

between the BART and an alternative 

were similar.111 This approach is 

reasonable, as visibility modeling is not 

needed to demonstrate that a greater 

reduction in emissions from a source 

will result in greater visibility benefits 

than a lesser reduction in emissions 

from the same source. Accordingly, to 

the extent that the regulations are not 

clear that the test applies where the 

geographic distribution of emissions is 

similar, our interpretation is a 

reasonable one. In concluding that this 

test is the appropriate one to apply, EPA 

is not ignoring the commenter’s 

argument that the TWG Alternative 

distributes emissions over time very 

differently than would BART, and that 

in the near term, visibility would 

improve more rapidly if EPA were to 

require the installation of BART 

controls sooner. It is not necessary to 

model the visibility impacts of the TWG 

Alternative and BART, however, to 

reach that conclusion.112

EPA is accordingly determining that 

the provisions for retiring capacity and 

installing SCR under the TWG 

Alternative achieve a similar geographic 

distribution of emissions and that the 

appropriate test to apply is whether the 

alternative provides for greater 

emissions reductions than BART. In 

applying that test, EPA considers it 

reasonable to consider the cumulative 

emissions under BART and the BART 

alternative, rather than to simply 

compare annual emissions in some 

future year under the two scenarios. 

This approach provides a reasonable 

mechanism to give credit to NGS for its 

early reduction in NOX emissions from 

the installation of combustion controls. 

The commenter also objects to EPA’s 

decision to approve a BART alternative 

that will not be fully implemented by 

2018. EPA agrees that the regional haze 

rule requires BART alternatives to be 

fully implemented by states by 2018, the 

end of the first planning period for 

states that were required to submit 

regional haze plans.113 As noted in the 

Proposed Rule, given the deadline for 

the submittal of regional haze SIPs, 

EPA’s regulations accordingly built in 

an additional five years beyond the 

BART compliance date for the 

implementation of BART 

alternatives.114

We note that in this action, although 

the TWG Alternative will not be fully 

implemented until 2044, NOX emissions 

from NGS have already declined from 

historical levels, and significant 

additional declines in emissions are 

expected in 2019 and again in 2030. 

Nonetheless, we acknowledge that we 

are looking forward to 2044 for full 

implementation of the TWG alternative, 

well beyond the 2018 date in the RHR. 

We explained the basis for our proposed 

decision to set the compliance period 

for the TWG Alternative in the 

Supplemental Proposal. EPA’s 

reasoning on this issue is grounded in 

CAA section 301 and the TAR. The TAR 

generally exempted Tribes from the 

CAA submittal deadlines that applied to 

States. EPA interprets the requirement 

in 40 CFR 51.308(e)(2)(iii) to constitute 

a reasonably severable RHR submittal 

deadline that applies to States but not 

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46534 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

115See 78 FR 8288, column 1, describing our 

proposed BART determination. See also 78 FR 

8289, section titled ‘‘Legal Rationale for Extending 

Compliance Schedule for Alternative Measures for 

NGS.’’ 

116See page 22 of the EarthJustice comment letter 

dated January 3, 2014 (document 0367 in the docket 

for this rule). 

117See document number 0372 in the docket for 

this rule. 

118 Id. page 21. 

119See Proposed Rule at 78 FR 8289 (February 5, 

2013). 120See RTC and references therein. In 2011, NGS 

emitted 19,900 tons of NOX, in 2012, NGS emitted 

nearly 16,500 tons of NOX and in 2013, nearly 

17,500 tons of NOX. 

to Tribes. If the alternative measure is 

promulgated by the State, it must 

‘‘submit[s] an implementation plan 

containing the following plan elements 

and include[s] documentation for all 

required analyses: . . . (iii) A 

requirement that all necessary emission 

reductions take place during the period 

of the first long-term strategy for 

regional haze.’’ Therefore, it is a 

required ‘‘plan element’’ for a State-only 

required implementation plan 

submittal. See 40 CFR 51.308(b)(3) 

(requirements for States to submit longterm strategies). Because it is not 

mandatory for the Tribe to submit a 

long-term strategy, there is no 

mandatory requirement for the Tribe to 

ensure that all emissions reductions 

from a better than BART alternative 

occur within some deadline. 

This result is equitable as well as 

reasonable. States were required to 

submit SIPs in 2007, allowing 11 years 

for a ‘‘better than BART’’ alternative to 

be achieved in 2018. Because this is a 

FIP for a source in Indian country, and 

we are only now implementing the 

requirement in 2014, it is equitable to 

extend the compliance time as well. 

Please see the RTC for a more detailed 

discussion. 

In summary, EPA is determining that 

the TWG Alternative is ‘‘better than 

BART’’ based on achieving greater NOX

emissions reductions over a similar 

geographic distribution, within the date 

of the goal specified in the RHR of 

achieving natural conditions in 2064. 

Given the requirement to cease 

conventional coal-fired generation at 

NGS in 2044, and with cumulative 

emissions over 2009 to 2044 being less 

than the BART Benchmark, the TWG 

Alternative satisfies the requirements of 

the RHR with respect to NOX BART as 

applied to Navajo Nation based on the 

TAR. 

Comment: EPA overestimated the 

BART Benchmark. 

Aside from its assertions that an 

approach using a BART Benchmark 

based on total emissions is not lawful 

under the CAA, one commenter (an 

organization representing itself and 

several other non-governmental 

organizations) stated that EPA’s 

assumptions in calculating a numerical 

value for the BART Benchmark 

included errors and improper credits. 

Specifically, the commenter asserted 

that: (1) EPA’s credit for the early 

installation of LNB/SOFA runs counter 

to the Regional Haze Rule, EPA’s 

longstanding policies, and EPA’s 

specific statements regarding the haze 

determination for NGS, (2) EPA’s 

proposal to delay BART due to the LNB/ 

SOFA credit creates a dangerous 

precedent that threatens to significantly 

undermine the regional haze program, 

(3) EPA made a number of errors in its 

calculations that all have the effect of 

artificially inflating the BART 

Benchmark. The specific errors 

purported by the commenter are 

outlined in more detail in the RTC. The 

commenter asserts that in total, 

assuming a final rule by July 1, 2014, 

their recommended revisions to the 

BART Benchmark would reduce the 

estimated emissions under BART during 

EPA’s chosen timeframe (2009–2044) by 

nearly 100,000 tons, a reduction of 

approximately 26 percent. The 

commenter asserted that if EPA persists 

in using the emission cap framework, 

EPA must correct the NOX cap to 

prevent alternatives from being 

compared to an artificially inflated 

estimate of total NOX emissions. 

Response: EPA disagrees with the 

assertion that we are delaying BART. As 

stated elsewhere in the RTC, as well as 

in our Proposed Rule and Supplemental 

Proposal, EPA did not propose to ‘‘delay 

BART.’’ EPA proposed to provide 

additional flexibility in the compliance 

timeframe for alternatives to BART.115

The commenter alleges that ‘‘EPA’s 

claimed reliance on ‘‘early’’ LNB/SOFA 

as an excuse to avoid or delay what is 

legally required is misplaced and 

without foundation in the facts or 

law.’’ 116 The commenter cites three 

sources to support its assertion that the 

LNB/SOFA credit runs counter to the 

RHR and EPA’s long-standing policies: 

(1) Page 18 of a report written by 

Victoria Stamper (Stamper Report), 

which was commissioned by the 

commenter and submitted as part of its 

comments,117 (2) page 35728 of the July 

1, 1999 Regional Haze Rule, and (3) 

section IV.D.4.d of the BART 

Guidelines.118 EPA disagrees with these 

assertions. 

First, the commenter’s use of 

quotation marks around the word 

‘‘early’’ implies that the LNB/SOFA 

modifications were not, as a factual 

matter, installed early. However, EPA 

notes that in 2008, when the operator of 

NGS began discussions with EPA 

regarding the permitting requirements 

associated with the significant increase 

in carbon monoxide (CO) emissions that 

would result from the installation of 

LNB/SOFA, EPA had already begun our 

process for evaluating BART for NGS, 

but had not yet proposed a BART 

determination or put forth our ANPR. 

Therefore, no requirement existed that 

mandated the installation of LNB/SOFA 

at NGS. In addition, the operator of NGS 

was aware that a BART determination, 

that would likely involve but may not 

be limited to LNB/SOFA, was 

forthcoming. As noted in our Proposed 

Rule, the operator of NGS could have 

waited until the compliance date for 

BART to initiate any reductions in NOX

emissions; however, the operator 

elected in 2008 to seek the necessary 

permit to install LNB/SOFA on one unit 

per year over 2009–2011.119 Thus, 

because the LNB/SOFA modifications 

were made in 2009–2011, NOX

emissions from NGS declined from a 

high of over 35,000 tons in 2002 to less 

than 20,000 tons after 2011.120 Although 

some of the decline in total NOX

emissions can be attributed to a 

decrease in capacity utilization (i.e., 

decline in heat input of approximately 

13 percent when comparing 2002 to 

2013), the dominant contributor to the 

decline in NOX emissions from NGS 

was from the installation of LNB/SOFA 

over 2009–2011. EPA considers these 

emission reductions to be real 

reductions that were not required (i.e., 

voluntary and surplus) and were 

achieved in advance of any actual 

requirement to reduce emissions (i.e., 

early). 

In addition, each of the three citations 

provided by the commenter does not 

support its assertions that our proposal 

to credit NGS for the early installation 

of LNB/SOFA runs counter to the 

Regional Haze Rule or EPA’s longstanding policies. These three citations 

merely address the appropriate baseline 

period to use in the five-factor BART 

analysis. Page 18 of the Stamper Report 

supports our use of 2001–2003 as the 

baseline period for our BART 

determination for NGS and cites to 64 

FR 35728 of the July 1, 1999 Regional 

Haze Rule that discusses EPA’s 

determination that the most appropriate 

baseline period would be over the 2001 

to 2004 timeframe. The baseline period 

is used for evaluating the costs and 

visibility benefits of controls. The 

Stamper Report also cites Section 

IV.D.4.d of the BART Guidelines at 40 

CFR Part 51 Appendix Y, that states 

baseline emissions should generally 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46535 

121See 78 FR 8284 (February 5, 2013). 

122We note that in State of North Dakota v. EPA, 

the U.S. Court of Appeals for the Eighth Circuit 

vacated and remanded EPA’s promulgation of a FIP 

for Coal Creek Station because EPA did not 

consider the existing pollution control technologies 

in use at Coal Creek Station that were voluntarily 

installed after the baseline period. This document 

is included in the docket for this rule. 

123See 78 FR 62511 (October 22, 2013). 

124See 77 FR 51620 (August 24, 2012). 

represent a realistic depiction of 

anticipated emissions for the source 

based on actual emissions from a 

baseline period. 

The commenter also cited the 

discussion in our Proposed Rule under 

Factor 3, where we described, in 2008, 

how the early installation of LNB/SOFA 

would not prejudice the implementation 

of more effective controls for BART. As 

stated previously, we did not use the 

LNB/SOFA credit to justify a less 

stringent determination of BART for 

NGS. The commenter characterizes the 

credit as a shift in course from the 

agreements and understandings 

established in 2008 during the PSD 

permit process for the installation of 

LNB/SOFA. EPA disagrees. As stated in 

our Proposed Rule, citing the Ambient 

Air Quality Impact Report from the 2008 

Proposed PSD Permit, EPA stated that 

the early installation of LNB/SOFA 

systems would not affect the baselines 

for cost or visibility improvements, and 

therefore will not influence EPA’s 

determination of the NOX reductions 

required for BART.121 EPA’s BART 

analysis for NGS was consistent with 

this statement. As previously noted, 

EPA used the 2001–2003 period as the 

baseline for determining costeffectiveness and visibility benefits of 

controls, and determined, based on our 

analysis of all five factors, that 

SCR+LNB/SOFA is an appropriate 

BART Benchmark for NGS. 

The commenter relies on EPA’s 

statements about the appropriate 

baseline period to support an assertion 

that in a BART analysis, EPA should not 

give consideration or credit for controls 

installed after the baseline period. As 

stated in section 5.0 of the RTC (section 

5.0), although we appropriately 

acknowledged the installation of LNB/

SOFA after the baseline period at NGS 

under Factor 3 (existing controls at the 

facility), our analysis of costeffectiveness and anticipated visibility 

benefits appropriately compared 

SCR+LNB/SOFA against the 2001–2003 

baseline period.122

EPA’s proposed credit for early 

installation of LNB/SOFA was not 

associated with our five-factor analysis 

or BART determination for NGS. Rather, 

EPA discussed the LNB/SOFA credit in 

our framework for evaluating 

alternatives to BART. Specifically, in 

discussing our framework for BART 

Alternatives, EPA calculated the 

cumulative NOX reductions achieved 

early because the operator of NGS 

elected to install LNB/SOFA on one unit 

per year over 2009–2011, instead of 

waiting for the compliance period for 

BART. In our Proposed Rule and 

Supplemental Proposal we used this 

value, the LNB/SOFA credit, when 

comparing BART Alternatives to BART. 

As discussed elsewhere in the RTC, 

EPA’s proposal to allow BART 

Alternatives to take credit for the early 

installation of LNB/SOFA at NGS is a 

reasonable use of our discretion under 

the TAR.123

EPA disagrees with the assertion that 

this credit creates a dangerous 

precedent that threatens to significantly 

undermine the regional haze program. 

EPA notes that part of our rationale for 

the better than BART framework for 

NGS (including the credit for the early 

installation of LNB/SOFA and the 

adjusted compliance timeframe for 

BART Alternatives) was the potential 

impacts to numerous tribes that rely on 

NGS and/or CAP, as well as EPA’s 

regulations specifying that SIP submittal 

deadlines that apply to states do not 

apply to Tribes (or to EPA when 

implementing FIPs in Indian country). 

Further, EPA notes that the relationship 

between NGS and CAP is unique, the 

only other BART-eligible source in 

Indian country is the Four Corners 

Power Plant, and EPA has already 

completed the BART determination and 

FIP for this facility.124

EPA also disagrees with the assertion 

that we overestimated the BART 

Benchmark and NOX Cap. The 

commenter argues that SCR can meet a 

lower emission limit than proposed by 

EPA and that EPA should have set a 

compliance date within 3.5 years. As 

discussed in Section 8.1 of the RTC, 

EPA disagrees that the BART 

Benchmark should be based on an 

emission limit of 0.040 lb/MMBtu and 

that compliance should be required in 

3.5 years. EPA is finalizing a BART 

Benchmark based on our determination 

requiring NGS to meet a limit of 0.055 

lb/MMBtu within five years of the 

effective date of the Final Rule. 

Therefore, EPA is not revising the BART 

Benchmark or NOX Cap to assume a 

limit of 0.040 lb/MMBtu or a shorter 

compliance time for BART. 

In addition, the commenter 

recommends that EPA use average heat 

input over the baseline period (i.e., over 

2001–2003) rather than the average over 

the pre-LNB/SOFA time period (i.e., 

average over 2001–2008) to calculate 

future emissions. The commenter notes 

that our calculations for costeffectiveness use baseline heat input 

over 2001–2003 to calculate pre- and 

post-control emissions (approximately 

5,264 tons per year). The commenter 

asserts that this inconsistency is 

arbitrary. The commenter correctly 

notes that EPA used the average heat 

input over 2001–2008 (the pre-LNB/

SOFA time period) to estimate 

emissions over 2009–2019 that would 

have occurred if the operator of NGS 

had not installed LNB/SOFA early, and 

emissions over 2019 to 2044 under 

BART (5,345 tons per year). The average 

heat input over the baseline period of 

2001–2003 was 191,505,266 MMBtu, 

while the average heat input over 2001– 

2008 was 194,373,910 MMBtu. This is a 

difference of about 1.5 percent. EPA 

agrees that use of the same 2001–2003 

baseline heat input value for estimating 

pre- and post-control emission rates is 

appropriate and consistent with the 

RHR and BART Guidelines, particularly 

in light of the goal of understanding the 

effect of a given control technology on 

emissions (i.e., assume identical values 

for baseline and future heat input to 

isolate the impact of control 

technologies). However, this approach 

does not mean that an average from the 

three-year baseline period (2001–2003) 

is most appropriate for estimating future 

emissions in determining the BART 

Benchmark. EPA notes that the use of 

average heat input for 2001–2008 

includes the baseline period 

recommended by the commenters and 

provides a larger data set, and therefore 

a more robust average value for 

estimating future emissions. EPA 

considers the use of an average value 

based on three years to be less robust 

than an average value based on eight 

years of data for representing potential 

future operation; therefore, EPA is 

retaining our use of the average heat 

input over 2001–2008 for estimating 

emissions over 2009–2044. EPA further 

notes that emission caps in permit 

requirements are typically established 

based on the facility’s potential to emit 

(PTE) and would thus be calculated 

using maximum heat input values. The 

highest observed annual heat input 

value was 199,398,687 MMBtu and, if 

used in the NOX cap, would result in a 

significantly higher BART Benchmark. 

The commenter also argues that in 

calculating the NOX cap, EPA should 

use a value that reflects an annual 

average for post-control emission rates 

rather than a rate based on a 30-day 

average limit of 0.055 lb/MMBtu. The 

commenter reviewed daily data from 

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46536 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

125See Table 3 of our Supplemental Proposal at 

78 FR 62516 (October 22, 2013). 

126See Table 3 of the report written by Nathan 

Miller and Raijit Sahu (Miller/Sahu Report) 

commissioned by the commenter and submitted 

with its comments. See document number 0370 in 

the docket for this rule. 

127See tab titled ‘‘Outage Cycle’’ in the document 

titled ‘‘EPA Analysis of BART Alternatives’’ in 

document number 0004 in the docket for this rule. 

128See document titled ‘‘EPA Analysis of BART 

Alternative.xlsx’’ in document 0004 in the docket 

for the rule. 

129See Table 2 of the Supplemental Proposal (78 

FR 62515, October 22, 2013) and document number 

0191 titled ‘‘Supplemental Better than BART 

Alterntives.xlsx’’ in the docket for this rule. 

2000 to 2013 and calculated the ratio of 

the maximum 30-day average rate to the 

annual rate for each year and 

determined an average ratio of 1.135. 

Based on this ratio, the commenter 

recommended that the BART emission 

limit of 0.055 lb/MMBtu (on a rolling 

average of 30 boiler operating days) be 

reduced by a factor of 1.135 as an 

estimate of what the annual average 

post-control emission rate would be at 

NGS (i.e., 0.048 lb/MMBtu). EPA agrees 

that generally, emission rates averaged 

over an annual basis are lower than 

emission rates averaged over a 30-day 

basis. However, EPA did not propose 

setting a BART limit for NGS on an 

annual average basis and EPA did not 

receive any comments suggesting that 

we do so. Without an enforceable 

annual limit, EPA considers it 

inappropriate to assume a lower 

emission rate in our calculation of the 

NOX Cap. We note that the BART 

Guidelines require that BART limits for 

EGUs be set on a rolling average of 30 

boiler operating days. Therefore, 

although the BART Guidelines would 

not preclude establishing multiple 

emission limits over different averaging 

periods, the BART Guidelines do not 

require it. 

Separately, the commenter also 

asserts that EPA overestimated the 

2009–2044 NOX Cap. The commenter 

represents EPA’s NOX Cap as the 

scenario it calls ‘‘CAP–1’’ with a value 

of 494,899 tons. This value is consistent 

with the 2009–2044 NOX Cap EPA 

proposed in our Supplemental 

Proposal.125 The commenter asserts that 

this value is overestimated because (1) 

actual heat input data should be used to 

calculate the NOX Cap; and (2) the LNB/ 

SOFA could be installed in two 

years.126 EPA disagrees with these 

assertions. 

The commenter argues that for the 

period of 2009–2013, actual heat input 

data should be used to calculate the 

NOX Cap instead of the average heat 

input value over 2001–2008. EPA 

acknowledges that actual heat input 

data is available for the 2009–2013 

period; however, EPA considers using 

the average value to be appropriate, 

recognizing that years of lower than 

average capacity utilization will be 

balanced with years of higher than 

average capacity utilization at NGS. 

The commenter also asserts that LNB/ 

SOFA could have been required in two 

years, on a separate compliance 

timeframe than installation of SCR and 

that this should have been incorporated 

in our calculation of the NOX Cap. EPA 

is not aware of any BART determination 

that required combustion controls on a 

different schedule than post-combustion 

controls. Although the commenter 

correctly notes that LNB/SOFA was 

installed in three years (on one unit per 

year over 2009–2011), EPA notes that 

the operator began the permitting 

process in 2008 and installed the LNB/ 

SOFA during periods of major outage 

for each unit, which occurs at NGS 

every six years for each unit.127 EPA 

expects that it would not have been 

practicable to require installation of 

LNB/SOFA within two years following 

the final rule because, in order to 

accommodate one year for permitting, it 

would have required major outages on 

all three units in the same year. 

Therefore, EPA does not consider it 

practicable to assume the LNB/SOFA 

would or could have been installed on 

a separate track from the SCR. 

Although the commenter makes 

assertions related to purported 

overestimations of the BART 

Benchmark and the 2009–2044 NOX Cap 

separately, the commenter combines all 

of the assertions together to argue that 

the 2009–2044 NOX Cap should be 

373,029 tons (121,870 tons, or 25 

percent, lower than EPA’s proposed 

2009–2044 NOX Cap of 494,899 tons). 

As outlined above, EPA disagrees than 

any of the purported corrections 

suggested by the commenter are 

necessary or appropriate for projecting 

annual emissions to calculate the 2009– 

2044 NOX Cap. 

Comment: EPA double-counted the 

benefits of LNB/SOFA. 

One commenter asserted that EPA 

double-counted the benefits of the early 

installation of LNB/SOFA, stating that 

EPA calculated cumulative emissions 

for the BART alternatives including the 

benefits of early reductions, then 

subsequently applied a LNB/SOFA 

credit again to BART alternatives. 

Response: EPA disagrees with the 

assertion that we double-counted 

emission reductions associated with the 

early installation of LNB/SOFA. 

In our February 5, 2013 proposed 

rule, EPA calculated the value of the 

LNB/SOFA credit based on the 

difference between total emissions 

under the BART scenario where LNB/

SOFA is installed concurrently with 

SCR and the actual scenario when LNB/ 

SOFA was installed early. The value of 

this credit was then applied to total 

emissions over 2009–2044 under 

Alternative 1.128 Although our 

calculation of emissions under 

Alternative 1 did account for actual 

emissions with early installation of 

LNB/SOFA, and thus applying the LNB/ 

SOFA credit to the BART Alternative 

may appear to be double counting, it is 

not double-counting because the BART 

Alternatives were compared against a 

BART Benchmark that also accounted 

for actual emissions with early 

installation of LNB/SOFA. Thus, both 

the BART Benchmark and Alternative 1 

were calculated the same way (actual 

emissions accounting for early LNB/

SOFA installation), and the LNB/SOFA 

credit was only applied to Alternative 1. 

An example of double-counting would 

have been if EPA had applied the LNB/ 

SOFA credit to cumulative emissions 

over 2009–2044 under Alternative 1 and 

then compared that value to total 

emissions over the same period under 

BART assuming LNB/SOFA and SCR 

were installed concurrently. 

In our October 22, 2013 Supplemental 

Proposal, EPA approached the 

calculation from a different but 

equivalent perspective. The new 

calculation approach was used because 

it was more intuitive to apply and 

understand in the context of an 

enforceable cap on NOX emissions. In 

the Supplemental Proposal, the BART 

Benchmark was established as the total 

emissions over 2009–2044 that would 

have occurred if LNB/SOFA and SCR 

were installed concurrently, five years 

following the effective date of the final 

rule. Total emissions under BART 

Alternatives were then calculated using 

actual emissions beginning in 2009 (i.e., 

accounting for the early installation of 

LNB/SOFA) and projections for future 

emissions. Thus, in the methodology 

used in the Supplemental Proposal, the 

LNB/SOFA credit was applied to the 

BART Benchmark and NOX Cap, rather 

than to the TWG Alternative. This 

method is equivalent to the one used in 

the Proposed Rule but does not give the 

appearance of double-counting. In our 

Supplemental Proposal and supporting 

documents, EPA included calculations 

to show that these two methods are 

equivalent.129 The two methods are 

equivalent because what matters in the 

‘‘better than BART’’ context is the 

difference between total emissions 

under BART and total emissions under 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46537 

the BART Alternative. Whether the 

LNB/SOFA credit is applied to BART or 

BART Alternatives will affect the 

absolute value of a total (e.g., using the 

numbers in Table 2 of the Supplemental 

Proposal, the LNB/SOFA credit 

represents a difference of 377,008 tons 

or 480,489 tons), but it does not affect 

the difference between BART and BART 

Alternatives. The method used in the 

Supplemental Proposal is more intuitive 

because BART and the BART 

Benchmark reflect total emissions over 

2009–2044 that would have occurred if 

LNB/SOFA were installed concurrently 

with SCR, and the BART Alternatives 

reflect actual emissions without further 

credit or modification. Because no 

credits or modifications are made to 

actual emissions under the BART 

Alternatives, this method is the more 

logical accounting methodology for 

determining compliance with the 2009– 

2044 NOX Cap. 

Comment: BART Alternatives would 

interfere with reasonable progress goals 

in other states. 

One commenter stated delaying the 

compliance date for BART will allow 

NGS to continue emitting pollutants in 

excess of the levels modeled by the 

WRAP and will interfere with the ability 

of Arizona, Utah, and Colorado to meet 

their reasonable progress goals for 2018. 

Response: The issue raised by the 

commenter is outside the scope of our 

rulemaking addressing the NOX BART 

requirements for NGS. Although 40 CFR 

51.308(d)(3) requires states to submit 

long-term strategies that are sufficient to 

ensure that the state has included all 

measures needed to achieve its share of 

emission reductions agreed to through 

the regional planning process, the 

Navajo Nation has not yet submitted a 

long-term regional haze strategy. In 

addition, EPA has not yet found it 

necessary or appropriate to address 

these requirements through a FIP. If 

EPA determines it is necessary or 

appropriate to do so, we will take 

appropriate action. 

Meanwhile, we note that for NGS, the 

WRAP assumed that NOX emissions in 

2018 would equal 10,611 tons per year. 

NOX emissions under the TWG 

Alternative, in turn, will range from 

approximately 13,000 to 15,000 tons per 

year following the closure of one unit 

(or equivalent curtailment) at the end of 

2019. We also note that the closure of 

one unit (or equivalent curtailment) by 

the end of 2019 would reduce not only 

NOX, but also emissions of SO2. Given 

the overall changes in emissions from 

the various regional haze actions since 

the WRAP made its projections, we will 

be better able to assess the need, if any, 

for further action once Arizona, Utah, 

and Colorado have prepared regional 

haze SIPs for the second planning 

period. 

J. Comments on the TWG Alternative 

and EPA’s Supplemental Proposal 

Comment: Opposition to TWG 

Alternative because it is premised on 

SCR as BART. 

One commenter argued that the 2009– 

2044 NOX Cap used for the TWG 

Alternative is unduly and arbitrarily 

stringent because it is based on a limit 

of 0.055 lb/MMBtu, which the 

commenter believes is too stringent 

because (1) EPA should not have 

determined that SCR is BART and (2) 

even if SCR were the appropriate basis 

for BART, 0.055 lb/MMBtu is not 

achievable. The commenter stated that 

because Arizona agricultural users will 

phase out their use of CAP Ag Pool 

water by December 2030 pursuant to the 

2004 Arizona Water Settlement Act 

(AWSA), capital costs that are collected 

in advance of SCR operation will be 

imposed on NIA users in exchange for 

no benefit. The commenter asserted that 

if EPA finalizes either of the ‘‘better 

than BART’’ alternatives without 

modification, it would be arbitrarily and 

capriciously apportioning compliance 

costs to NIA water users for which they 

are not responsible. Given EPA’s 

acknowledgment of the compliance 

flexibility that exists with respect to the 

TAR, the commenter believes that the 

failure to consider potential ‘‘better than 

BART’’ alternatives that would afford 

compliance flexibility to all NGS 

stakeholders on an evenhanded basis 

constitutes an abuse of discretion on the 

part of EPA. 

Response: EPA disagrees with the 

assertion that the TWG Alternative is 

unduly and arbitrarily stringent because 

it is based on a BART limit of 0.055 lb/ 

MMBtu. We consider the limit of 0.055 

lb/MMBtu to appropriate for 

establishing the BART Benchmark for 

NGS. EPA addressed specific comments 

related to the BART limit in section 8.1 

of the RTC. We also note that the TWG 

Alternative was developed as an 

agreement between diverse 

stakeholders, including SRP, the 

operator of NGS on behalf of itself and 

other co-owners, and the CAWCD. 

Although both entities submitted 

comments in opposition to the proposed 

BART limit of 0.055 lb/MMBtu, both 

parties signed the TWG Agreement that 

establishes the NOX Cap based on the 

proposed BART limit of 0.055 lb/

MMBtu. 

The commenters indicate that their 

access to CAP Ag Pool water is expected 

to end in 2030, and assert that the 

timeframes for compliance with the 

limit of 0.07 lb/MMBtu in 2030 would 

necessitate water rate increases prior to 

2030. The commenter asserts that it is 

arbitrary and capricious for NIA water 

users to pay a few years of higher CAP 

water rates for controls that will not be 

operational until after their access to the 

CAP Ag Pool expires. EPA notes that the 

direct impact of compliance with the 

limit of 0.07 lb/MMBtu in 2030 under 

the TWG Agreement, presumably with 

installation and operation of SCR, 

would be on the cost of electricity 

generation. Increasing water rates are 

indirect impacts that result from the 

relationship between NGS and CAP. 

EPA does not set or determine water 

rates charged by CAWCD to the CAP Ag 

Pool or any other classes of CAP 

customers. EPA’s proposed and final 

approval of requirements consistent 

with the TWG Agreement as a ‘‘better 

than BART’’ alternative is based on our 

review of the anticipated emission 

reductions associated with the TWG 

Alternative compared to BART. 

Although EPA, DOI, and DOE have 

committed to work together on many 

issues related to NGS, including funding 

for the federal portion of capital 

improvements at NGS, EPA does not 

determine how controls would be 

financed and how and when electricity 

or water rates would be adjusted to 

recover costs. 

Comment: TWG Alternative does not 

fully meet EPA’s obligations to the Gila 

River Indian Community. 

The Gila River Indian Community 

said that even though it fully supports 

the TWG Alternative, it is concerned 

that EPA has not met its obligations to 

the Community because of the 

significant costs on NGS and associated 

impacts on the Community. Rather, the 

commenter views the TWG Alternative 

as the first step in a process that will 

limit the impacts on the Community 

because only under the TWG 

Alternative will key U.S. commitments 

contained in the TWG Agreement be 

realized. Specifically, under the TWG 

Agreement, and as outlined by the 

commenter, DOI will work with the 

Community and other tribes in the area 

around NGS, to evaluate the actual 

impacts the regulatory requirements 

will have on NGS over time. The 

commenter specifically referred to the 

U.S. commitment to allocate $10 million 

annually for 10 years starting in 2020, 

from the Reclamation Water Settlements 

Fund to reduce impacts to the 

Development Fund. 

Response: EPA acknowledges the 

comment and is aware that costs 

associated with implementing the TWG 

Alternative will have implications for 

numerous Tribes, including the Gila 

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46538 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

130See RTC and references therein. 

River Indian Community. EPA is 

committed to continuing to work with 

the Department of the Interior and the 

Department of Energy in the Interagency 

Working Group on NGS, as laid out in 

the Joint Statement signed in January 

2013 by the heads of the three agencies, 

to work with tribes to address long-term 

issues related to NGS. The provisions in 

the TWG Agreement that are not related 

to EPA’s authority to evaluate BART or 

a ‘‘better than BART’’ alternative, 

however, are beyond the scope of this 

rulemaking. 

Comment: TWG Alternative is vague 

and unenforceable. 

One commenter stated that a BART 

determination must include clear 

requirements for emissions reductions 

and a clear timeline for those 

reductions, to ensure continuing 

visibility improvements in Class I areas. 

The commenter indicated that without 

specific emission limits and/or 

commitments to retire specific amounts 

of capacity from specific units, as of a 

date certain, it is impossible to calculate 

the visibility improvements that will 

result from the TWG Alternative, 

particularly TWG Alternatives A3 and 

B, and it will be impossible for 

individuals or EPA to assess whether 

NGS is on track to meet the emission 

reductions necessary to ensure 

reasonable progress toward natural 

visibility in affected Class I areas. 

Response: EPA disagrees with the 

assertion that the TWG Alternative is 

vague and unenforceable. EPA 

acknowledges that the TWG Alternative 

provides flexibility in a manner that 

appears complex. This complexity is a 

result of the role future ownership 

outcomes will have in determining the 

most reasonable compliance options in 

the future. Once the ownership issues 

are resolved, the scope of options under 

the TWG Alternative narrows. Although 

some flexibility still remains in the 

TWG Alternative, particularly under 

TWG Alternative B, the options for 

future operation of NGS are bounded by 

the limitations provided by the 2009– 

2044 and 2009–2029 NOX Caps. 

Contrary to the assertions by 

commenters, EPA included proposed 

regulatory language in our 

Supplemental Proposal that provided 

specific and enforceable timelines for 

achieving emission reductions under 

the TWG Alternative. The proposed 

language under 40 CFR 49.5513(j)(3)(i), 

‘‘Operating Scenarios to Comply with 

2009–2044 NOX Cap,’’ defines the 

timeframes and requirements under 

TWG Alternatives A1, A2, A3, and B, all 

of which must be implemented in a 

manner that ensures total NOX

emissions over 2009–2044 remain below 

the 2009–2044 NOX Cap. Specifically, 

§ 49.5513(j)(3)(i)(A) defines Alternative 

A1, and specifies the following 

requirements: (1) By December 31, 2019, 

the owner/operator shall permanently 

cease operation of one coal-fired unit 

and (2) by December 31, 2030, the 

owner/operator shall comply with a 

NOX emission limit of 0.07 lb/MMBtu 

on each of the two remaining coal-fired 

units. Alternative A1 is the simplest of 

the possible operating scenarios under 

the TWG Alternative and 

§ 49.5513(j)(3)(ii)(A) specifies that 

Alternative A1 applies under three 

potential future ownership possibilities. 

TWG Alternative A2 is defined in 

§ 49.5513(j)(3)(i)(B) and requires (1) by 

December 31, 2019, the owner/operator 

shall permanently cease operation of 

one coal-fired unit, and (2) by December 

31, 2019, the owner/operator may elect 

to increase net generating capacity of 

the remaining two coal-fired units by a 

combined total of no more than 189 

MW. The actual increase in net 

generating capacity shall be limited to 

the sum of 19 MW and the ownership 

interest, in net MW capacity of up to 

170 MW, purchased by the Navajo 

Nation by December 31, 2019. The 

owner/operator shall ensure that any 

increase in the net generating capacity 

is in compliance with all preconstruction permitting requirements, 

as applicable, and (3) by December 31, 

2030, the owner/operator shall comply 

with a NOX emission limit of 0.07 lb/

MMBtu on each of the two remaining 

coal-fired units. The future ownership 

possibilities that would trigger 

Alternative A2 are defined in 

§ 49.5513(j)(3)(ii)(B). 

TWG Alternative A3 is defined in 

§ 49.5513(j)(3)(i)(C) and requires (1) by 

December 31, 2019, the owner/operator 

shall reduce net generating capacity of 

NGS by no less than 561 MW. The 

actual reduction in net generating 

capacity of NGS shall be determined by 

the difference between 731 MW and the 

ownership interest, in net MW capacity 

of up to 170 MW, purchased by the 

Navajo Nation by December 31, 2019, 

and (2) by December 31, 2030, the 

owner/operator shall comply with a 

NOX emission limit of 0.07 lb/MMBtu 

on two units. The future ownership 

possibilities that would trigger 

Alternative A2 are defined in 

§ 49.5513(j)(3)(ii)(C). 

TWG Alternative B is defined in 

§ 49.5513(j)(3)(i)(D) and requires that in 

addition to the 2009–2044 NOX Cap, the 

owner/operator shall ensure compliance 

with the 2009–2029 NOX Cap. The 

2009–2044 NOX Cap is defined in 

§ 49.5513(j)(2)(ii) as no more than 

494,899 tons of NOX, and the 2009–2029 

NOX Cap is defined in § 49.5513(j)(2)(i) 

as no more than 416,865 tons of NOX. 

The 2009–2029 NOX Cap is based on 

closure of one unit by December 31, 

2019 and the 2009–2044 NOX Cap is 

based on compliance with the BART 

emission limit of 0.055 lb/MMBtu by 

July 1, 2019. The future ownership 

possibilities that would trigger 

Alternative B are defined in 

§ 49.5513(j)(3)(ii)(D). As described in 

§ 49.5513(j)(4)(iv), if TWG Alternative B 

is triggered, the owner/operator must 

submit annual Emission Reduction 

Plans that contain the anticipated yearby-year emissions to ensure compliance 

with the 2009–2029 and 2009–2044 

NOX Caps. 

The commenter asserts that under the 

scenario of reduced capacity (three units 

remain open, i.e., TWG Alternative A3), 

EPA ignored other possible outcomes 

and simplistically assumed that two 

units would continue to operate at full 

capacity with SCR and the unit whose 

operation is curtailed would operate 

only with LNB/SOFA. The commenter 

asserts that there is no guarantee that 

the operator will choose to comply with 

TWG Alternative A3 in this manner. 

Although this specific arrangement 

under TWG Alternative A3 is not 

required, EPA disagrees that nothing 

compels the operator to comply with 

this operating scenario in a manner that 

reduces emissions comparably with the 

assumption that two units would 

operate at full capacity with SCR and 

the unit that is curtailed would operate 

with LNB/SOFA. EPA notes that under 

TWG Alternative A3, as well as all other 

TWG Alternatives, the owner/operator 

must operate the units at NGS so that 

total emissions remain below the 2009– 

2044 NOX Cap (as well as the 2009– 

2029 NOX Cap under Alternative B). For 

example, under TWG Alternative A3, if 

the operator chose to curtail all three 

units by a total of 561 MW equally and 

comply with a limit of 0.07 lb/MMBtu 

on two units and 0.24 lb/MMBtu on one 

unit, total emissions over 2009–2044 are 

not likely to comply with the 2009–2044 

NOX Cap.130 Thus, the operator would 

be prohibited from operating in this 

manner and would need to, for example, 

significantly curtail operations to reduce 

emissions further, or risk violating the 

FIP. 

As noted in our Supplemental 

Proposal, EPA estimated total NOX

emissions over 2009–2044 for TWG 

Alternatives A1, A2, and A3 to provide 

assurance that the owner/operator could 

reasonably meet the 2009–2044 NOX

Cap under the specific terms of those 

alternatives. EPA does not need to 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46539 

131The combination of the 2009–2044 and 2009– 

2029 NOX Caps under TWG Alternative B means 

that if NGS exceeds the 2009–2029 NOX Cap prior 

to 2029 it must cease operation, but the operator 

may re-start operation after 2030 as long as 

cumulative emissions have not yet exceeded the 

2009–2044 NOX Cap. 

132See EarthJustice letter, page 10, footnote 25. 

133See Supplemental Proposal, 78 FR 62513, 

footnote 21 (October 22, 2013). 

134 40 CFR 51.308(d). 

135See Footnote 60 in the Proposed Rule, 78 FR 

8290 (February 5, 2013). 

determine that all operating possibilities 

that are consistent with the 

requirements of TWG Alternative A1, 

A2, and A3 would also meet the 2009– 

2044 NOX Cap. The regulatory 

requirements EPA is finalizing for the 

TWG Alternative provide specific dates 

on which the owner/operator must close 

a unit, curtail operations, and meet 

emission limits. While there is some 

flexibility in how emissions might be 

curtailed under TWG Alternative A3, 

the 2009–2044 NOX Cap ensures that 

the operator does not implement a 

strategy that results in substantially 

more emissions than would be achieved 

by installing SCR on the two units that 

are operated at full capacity and 

curtailing operations on the unit that 

was not retrofit with SCR. 

The commenter asserts that there are 

an infinite number of ways the operator 

could comply with the 2009–2029 and 

2009–2044 NOX Caps under TWG 

Alternative B. The commenter further 

states that the two possibilities EPA 

considered in our Supplemental 

Proposal are not likely to be the 

outcomes under TWG Alternative B. 

EPA agrees that TWG Alternative B 

provides more flexibility than TWG 

Alternative A. However, EPA disagrees 

that TWG Alternative B is so openended that it would not be enforceable 

or result in emission reductions at NGS. 

We note that the 2009–2029 NOX Cap 

was calculated based on the closure of 

one unit with no additional increase in 

capacity (i.e., equivalent to emissions 

under TWG Alternative A1). Thus, the 

operator cannot maintain the status quo 

(operation of all three units at full 

capacity at a limit of 0.24 lb/MMBtu) 

and meet the 2009–2029 NOX Cap. We 

recognize that several commenters are 

concerned about the flexibility under 

TWG Alternative B. However, as 

discussed further in the RTC, we note 

that the range of possible operating 

choices for TWG Alternative B is 

substantially constrained by the 

requirement to comply with the 2009– 

2029 and 2009–2044 NOX Caps. 

Although we disagree with 

commenters that the TWG Alternative is 

vague and unenforceable, in response to 

the concerns expressed by these 

commenters, to provide additional 

assurance that cumulative emissions of 

NOX from NGS under the TWG 

Alternative will not exceed the BART 

Benchmark, EPA is adding the following 

provisions to the Final Rule. Under all 

Alternatives, if cumulative emissions of 

NOX from NGS exceed the 2009–2044 

NOX Cap prior to 2044, the operator of 

NGS must permanently cease operation 

of NGS. In addition, under Alternative 

B, if cumulative emissions of NOX

exceed the 2009–2029 NOX Cap prior to 

2029, the operator of NGS must 

temporarily cease operation of all units 

at NGS.131

One commenter asserted that EPA 

was incorrect to claim that the TWG 

Alternative would absolve NGS of 

obligations related to a Reasonably 

Attributable Visibility Impairment 

(RAVI) finding that may be made for 

NGS.132 EPA disagrees that we claimed 

that the TWG Alternative would absolve 

NGS of obligations related to RAVI. The 

commenter cited to footnote 21 in our 

Supplemental Proposal.133 In that 

footnote, we acknowledged that the 

TWG had intended their alternative to 

satisfy both the ‘‘better than BART’’ 

requirements of the RHR as well as any 

requirements of the RAVI program. Our 

footnote merely noted that there was no 

outstanding petition to certify 

impairment from NGS at any Class I 

area and outlined the process and 

requirements for triggering a BART 

determination under RAVI. Although 

we stated that a BART determination 

under RAVI would likely be the same as 

a BART determination under regional 

haze (i.e., an analysis of the five factors 

listed in the CAA), EPA did not make 

any conclusions or absolve NGS of any 

obligations related to RAVI because 

there is currently no action before EPA 

to make an attribution finding related to 

NGS. 

EPA is finalizing the requirements of 

the TWG Alternative, consistent with 

Appendix B of the TWG Agreement, 

which require, among other things, 

emission reductions in 2019 and 2030. 

EPA is also adding as an enforceable 

requirement, the commitment from the 

TWG Agreement to cease conventional 

coal-fired electricity generation at NGS 

by 2044. EPA considers these 

timeframes to be consistent with the 

stated goal of section 169A of the CAA. 

EPA has addressed comments regarding 

consistency with EPA’s regulations, 

including the RHR and the TAR, in 

section 8.5 of the RTC. 

Comment: Additional concerns with 

TWG Alternative. 

The Hopi Tribe indicated that it has 

serious concerns with the proposed 

TWG Alternative for several reasons, 

including because the TWG Alternative 

does not specify the technology, i.e., 

either SCR or an equivalent that will be 

used to achieve the same level of NOX

reductions as the BART proposal. The 

commenter states the TWG Alternative 

is ambiguous because both scenarios are 

vague and do not include the same level 

of assurance that the NOX reductions 

will be the same as under the BART 

proposal. Also, because the time NGS 

would be permitted to operate without 

SCR (or equivalent alternative) would be 

adjusted under the TWG Alternative, 

the commenter believes the TWG 

Alternative jeopardizes the goal of the 

CAA and the purpose of this regulation. 

Response: Our proposed BART 

determination did not specify what 

technology must be used because BART 

is defined as an emission limit that 

represents the level of control 

representing BART, not a particular 

technology. Thus, our Proposed Rule 

and the Supplemental Proposal both 

imposed emission limits for NOX. The 

limits for BART (0.055 lb/MMBtu) and 

the TWG Alternative (0.07 lb/MMBtu) 

are based on what is achievable using a 

specific technology. Both limits are 

achievable with SCR, but the operator 

may consider using newer technologies, 

if available, as long as each unit 

complies with its applicable emission 

limit by its compliance date. The 

commenter also noted that the extended 

period for compliance under the TWG 

Alternative may jeopardize the goal of 

the CAA and the purpose of the RHR. 

Under section 169A of the CAA and the 

RHR, the goal of restoring visibility in 

Class I areas to natural conditions is set 

for 2064.134

Comment: ‘‘Arbitrary’’ 2044 end date. 

One commenter stated that the 2009– 

2044 period analyzed for the TWG 

Alternative is arbitrary because it is 

quite likely that one or more NGS units 

will operate beyond that time frame. 

The commenter asserted that if NGS 

units continue to operate for even 3 

additional years, until 2047, the TWG 

Alternative permits outcomes that will 

result in greater total NOX emissions 

than the 2009–2044 NOX Cap. 

Response: EPA disagrees with the 

comment that the 2044 end date for the 

NOX Cap is arbitrary. EPA used 2044 as 

the end date in our calculations of the 

BART Benchmark. We selected 2009– 

2044 as most appropriate because it 

includes the early installation dates for 

LNB/SOFA and extends until the 

anticipated 2044 termination date of the 

renewed site lease that was approved by 

the Navajo Nation.135 Under the TWG 

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136See Section VII.F of the TWG Agreement (page 

14). 137Miller/Sahu Report, Table 2 at p. 7. 

138See Exhibit 2 to the Miller/Sahu report and 

RTC and references therein. 

139See RTC and references therein. 

140 Id. 

Agreement signed by six entities 

including the Navajo Nation and SRP, 

the NGS Co-Tenants shall cease their 

operation of conventional coal-fired 

generating at NGS no later than 

December 22, 2044. At its election, 

consistent with the Lease Amendment, 

the Navajo Nation may continue plant 

operations at NGS after December 22, 

2044 consistent with EPA approval.136

Thus, the Navajo Nation may seek to 

operate NGS after 2044, however, EPA 

expects that operation of NGS after the 

owners cease conventional coal-fired 

generation would involve substantial 

modification to NGS and NGS would be 

required to meet all applicable 

regulatory and permitting requirements 

in existence at that time. To make this 

end date federally-enforceable, EPA is 

adding it as a requirement to the 

regulatory language in today’s final 

action. EPA is adding the regulatory 

language in the Final Rule under 40 CFR 

49.5513(j)(3)(iii) stating that by 

December 22, 2044, the owner/operator 

shall permanently cease operation of all 

coal-fired units at NGS. At its election, 

the Navajo Nation may continue plant 

operation at NGS after December 22, 

2044, consistent with EPA approval 

under the New Source Review program. 

Comment: Emissions under the TWG 

Alternative. 

One commenter stated that neither 

EPA nor TWG have provided a 

comprehensive technical analysis of the 

emissions that are possible under the 

TWG Alternative. The commenter 

asserted that it is EPA’s responsibility to 

provide an administrative record that 

contains comprehensive modeling and 

analysis for any BART proposal, but 

EPA left this critical component of the 

alternatives analysis undone. 

The commenter provided its own 

calculations of emissions under TWG 

Alternative A and B and compared 

those estimates with its own calculation 

of a NOX Cap and BART Benchmark, 

and concluded that cumulative 

emissions from possible scenarios under 

the TWG Alternative are not lower than 

its NOX Cap or BART Benchmark. 

Response: EPA disagrees with the 

comment that we have failed to provide 

a comprehensive technical analysis of 

the TWG Alternative. We also disagree 

with the assertion that our 

administrative record for this 

rulemaking is incomplete. As stated 

elsewhere in the RTC, EPA’s analysis of 

the TWG Alternative is consistent with 

the required analyses for alternatives to 

BART outlined in the RHR. 

The comment relies on a report 

prepared by Nathan Miller and Ranijit 

Sahu (Miller/Sahu) for the commenter 

contending that EPA’s evaluation of the 

TWG Alternative is incorrect. But the 

report changes the central inputs 

underlying our calculations for BART 

and the TWG Alternative. The specific 

technical reasons that we disagree with 

the inputs that Miller/Sahu changed 

(e.g., NOX emissions limit achievable 

with SCR, heat input values from 

baseline period, annual vs. 30-day 

emission rates) are explained in detail 

in section 8.5 of the RTC. 

Table 2 in the Miller/Sahu report 

depicts BART–1 as ‘‘EPA BART (No 

Corrections),’’ showing a value of 

379,152 tons of cumulative NOX

emissions over 2009–2044 that is 

nowhere traceable to EPA’s 

documents.137 The Miller/Sahu report 

then makes several ‘‘corrections’’ to 

reach a value of 280,554 tons of NOX

emissions. EPA has explained in detail 

why we disagree with each of the 

Miller/Sahu ‘‘corrections’’ in section 8.5 

of the RTC and references therein. For 

the reasons set forth in section 8.5, we 

also continue to disagree that our 

calculation of the BART Benchmark or 

the NOX Cap has relied on any incorrect 

inputs. 

Because we disagree with the 

‘‘corrections’’ and the values presented 

in the Miller/Sahu report, we also 

disagree with the conclusions of Miller/ 

Sahu that the TWG Alternative fails to 

satisfy our requirements for 

demonstrating an alternative is ‘‘better 

than BART’’. The commenter cannot 

change the fact that its alternative 

preferences on the inputs for calculating 

BART are just preferences by simply 

calling them ‘‘corrections.’’ 

Comment: Visibility modeling under 

the TWG Alternative. 

One commenter stated that the TWG 

Alternative distributes emissions over 

time very differently than BART: While 

BART would require NOX reductions 

within 5 years, the bulk of the 

reductions in the TWG Alternative 

might not come until the end of the 

2009–2044 period. The commenter 

stated that the additional analysis and 

modeling it conducted reveals that the 

TWG Alternative is likely substantially 

worse than BART. 

Response: As discussed elsewhere in 

this document, because emission 

reductions achieved under the TWG 

Alternative will have the same 

geographic distribution as emission 

reductions under BART, EPA disagrees 

that visibility modeling is required for 

our evaluation of the TWG Alternative. 

We note that the commenter provided 

its own visibility modeling and EPA 

disagrees with methodologies used and 

conclusions drawn by the commenter. 

The Miller/Sahu Report compared 

anticipated visibility impacts from the 

TWG Alternative against the anticipated 

visibility impacts based on its own 

preferences for the NOX Cap and BART 

Benchmark. Although the commenter 

asserts that its analysis shows that 

visibility under the TWG Alternative is 

substantially worse than under its 

preferences for the BART Benchmark 

and NOX Cap, their analysis also shows 

that when the TWG Alternative is 

compared to the BART Benchmark and 

NOX Cap as proposed by EPA, the TWG 

Alternative scenarios it explored that 

meet the 2009–2044 and 2009–2029 

NOX Caps (as applicable) generally 

result in lower or comparable visibility 

impacts as BART.138

EPA conducted visibility modeling to 

compare TWG Alternatives A1, A2, and 

A3 in 2019 and 2030 against the BART 

Benchmark.139 As indicated by 

commenters, other possibilities exist 

beyond the scenarios for the TWG 

Alternatives we considered explicitly in 

our Supplemental Proposal. EPA has 

stated elsewhere that we need not 

consider potential emissions under all 

possible scenarios in setting the NOX

Cap, but must verify that NGS can 

reasonably be expected to comply with 

2009–2044 NOX Cap under the various 

constraints imposed under the TWG 

Alternatives (i.e., closure, curtailment, 

and a secondary 2009–2029 NOX cap). 

However, EPA explored two other 

possibilities under TWG Alternative A3 

that included reducing capacity on all 

three units equally or reducing capacity 

on two units and installing SCR on the 

two units that operate at reduced 

capacity.140 EPA did not include those 

two additional possibilities under TWG 

Alternative A3 in our visibility 

modeling analysis because those 

scenarios do not reduce emissions 

sufficiently to meet the 2009–2044 NOX

Cap. 

Our visibility modeling of the TWG 

Alternatives compared to our proposed 

BART determination shows that, as 

expected, during the approximate 10- 

year period between 2019 and 2030, the 

visibility impacts of NGS under the 

TWG Alternatives are higher than the 

visibility impacts of NGS under BART. 

After 2030, when NGS achieves 

additional emission reductions through 

compliance with a limit of 0.07 lb/

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141EPA expects that if the Navajo Nation elects 

to operate NGS after the owners have ceased 

conventional coal-fired generation, this would 

likely involve substantial modifications to NGS and 

NGS would be subject to all applicable regulatory 

and permitting requirements in existence at that 

time. 

MMBtu on two units, our modeling 

indicates that the visibility impacts 

under the TWG Alternatives are 

comparable to or lower than visibility 

impacts under BART (see RTC for 

further detail). These results are not 

surprising and mirror the comparative 

reduction in NOX emissions under the 

TWG Alternatives and the BART 

Benchmark over time, showing greater 

overall visibility improvement under 

the TWG Alternative than under the 

BART Benchmark. 

As noted elsewhere in the RTC, EPA 

is including as part of the TWG 

Alternative, in the regulatory language 

in the Final Rule, a provision consistent 

with the TWG Agreement that the 

operator of NGS permanently cease 

conventional coal-fired generation by 

the end of 2044. Thus, under the TWG 

Alternative, the visibility impact of NGS 

is likely to be zero or near zero in 2045 

and thereafter.141 Under BART, there 

would be no commitment or enforceable 

requirement to close after 2044, 

therefore, visibility impacts of NGS at 

all 11 Class I areas would be expected 

to continue in 2045 and thereafter. 

Comment: Economic Impacts of the 

TWG Alternative. 

The Hopi Tribe expressed concern 

that EPA did not assess the potential 

economic impacts of the TWG 

Alternative to the Hopi Tribe. The 

commenter opined that EPA recognized 

the significance of NGS to the Hopi 

Tribe in its analysis under Factor 2. 

Because the TWG Alternative includes 

closure of at least one unit in 2019, and 

EPA did not address the potential 

economic impacts of partial closure of 

NGS on the Hopi Tribe, the commenter 

contended that the Agency has not 

complied with the RHR and BART 

Guidelines. The Hopi Tribe noted that 

in the event capacity is reduced at NGS 

under the Supplemental Proposal, the 

amount of coal and water purchases 

from the Tribe would decrease leading 

to a decrease in income to the tribe from 

the sale of these. The commenter also 

stated that the Supplemental Proposal is 

not as effective in improving air quality 

and visibility for the Hopi Reservation. 

Extending the timeframe during which 

NGS can continue to operate without 

SCR or an equivalent technology would 

cause a continued air quality burden on 

the Hopi Tribe. 

Response: EPA recognizes that the 

TWG Alternative, which includes 

closure of one unit at NGS or equivalent 

curtailment of operation, may change 

the royalties and other payments related 

to coal and water that are paid to the 

Hopi Tribe. Although EPA evaluated 

cost-effectiveness and affordability of 

the options in our analysis of BART 

controls, we disagree that we must also 

conduct an economic impact analysis 

for alternatives to BART. The BART 

Guidelines provide little guidance on 

the evaluation of alternatives to BART 

and the RHR does not require an 

analysis of economic impacts of BART 

Alternatives. EPA’s evaluation of 

potential impacts to tribes in our 

analysis of BART controls was used to 

inform our government-to-government 

consultation with tribes and is 

consistent with BART. In addition, we 

have held numerous government-togovernment consultation meetings with 

tribes to discuss NGS during this 

rulemaking. EPA continues to recognize 

the issues and concerns of tribes located 

in Arizona regarding NGS and is 

committed to continuing to work with 

our federal partners and the tribes 

through the Joint Federal Agency Work 

Group on NGS to help address these 

issues. 

The Hopi Tribe also expressed 

concern that the TWG Alternative is less 

effective than BART at improving air 

quality and visibility on the Hopi 

Reservation. EPA notes that the purpose 

of the RHR is to reduce visibility 

impairment at Class I areas; however, 

EPA disagrees that the TWG Alternative 

is less effective than BART. Although 

the timeframe for implementation of the 

TWG Alternative (new reductions in 

2019 and 2030) is longer than the 

timeframe for BART (in 2019), we note 

that BART would only reduce emissions 

of NOX, whereas the TWG Alternative, 

in 2019, would also reduce emissions of 

SO2, PM, CO2, and hazardous air 

pollutants as a result of the closure of 

one unit (or equivalent curtailment). 

Comment: Support for some changes 

EPA made to the TWG Agreement in the 

Supplemental Proposal. 

The TWG noted that there were 

several differences between Appendix B 

to the TWG Agreement and EPA’s 

Supplemental Proposal of the TWG 

Alternative. The commenters expressed 

support for some of the differences, and 

expressed concern with others. One 

commenter agreed with the 

methodology that EPA used to calculate 

the 2009–2044 NOX Cap of 494,899 

tons. 

The commenter supported the 

additional requirement to report annual 

heat input, although this information is 

already reported through the Acid Rain 

Program. However, the commenters 

requested that additional time be 

provided to ensure that the data 

submitted in the annual report are 

consistent with the data that the NGS 

operator submits to the Clean Air 

Markets Database (CAMD), in the 

annual emission inventory, and in the 

greenhouse gas (GHG) report required 

by 40 CFR part 98, which are not due 

until March 31st. 

Response: EPA recognizes that the 

TWG supports some of the changes EPA 

made to Appendix B to the TWG 

Agreement, including EPA’s revisions to 

the 2009–2044 NOX Cap and the 

requirement to report annual heat input. 

EPA agrees that it is reasonable to 

require the timeframe for the reporting 

requirements under BART to generally 

be more consistent with other reporting 

requirements. Therefore, EPA is revising 

the regulatory language accordingly. 

Comment: Suggested addition to 

§§ 49.5513(j)(4)(iv)(A) and (B). 

The TWG requested that EPA clarify 

the scope and content of the title V 

permit revision that is necessary to 

incorporate elements of the BART 

alternative by adding the language from 

Appendix B of the TWG Agreement to 

the requirements of the TWG 

Alternative. 

Response: EPA did not include the 

language from the TWG Agreement 

related to the title V (part 71) operating 

permit in the regulatory language in our 

Supplemental Proposal because the title 

V (part 71) regulations require that the 

operating permits include all applicable 

requirements, which for NGS would 

include the permit limits that exist in its 

PSD permit (i.e., the limit of 0.24 lb/

MMBtu when operating with LNB/

SOFA) as well as the final requirements 

in this FIP (e.g., the limit of 0.07 lb/

MMBtu on two units in 2030). 

Therefore, a specific requirement in the 

FIP that directs the operating permit to 

incorporate applicable requirements is 

not necessary. However, to the extent 

the TWG requests consistency with the 

language in the TWG Agreement, 

although EPA considers it unnecessary, 

EPA will amend § 49.5513(j)(4)(iii) as 

suggested by the commenter. 

We further note that in the proposed 

regulatory language in our 

Supplemental Proposal, EPA 

inadvertently did not specify an 

averaging period for the emission limits 

under the TWG Alternative Operating 

Scenarios (§ 49.5513(j)(3)). Therefore, 

EPA is adding to the regulatory language 

that emission limits apply over a rolling 

average of 30 boiler operating days, to 

40 CFR § 49.5513(j)(3), (j)(3)(i)(A)(2), 

(j)(3)(i)(B)(3), and (j)(3)(i)(C)(2). 

Comment: Another suggested addition 

to §§ 49.5513(j)(4)(iv)(A) and (B). 

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The TWG stated that the 

Supplemental Proposal specified a 

short-term NOX limit of 0.07 lb/MMBtu 

for TWG Alternative A, but not for 

Alternative B as was included in the 

TWG Agreement. 

Response: EPA agrees that if the 

owners of NGS elect to install SCR in 

order to comply with the applicable 

NOX Caps under TWG Alternative B, 

then it is useful to specify the emission 

limit that would apply. Although the 

limit of 0.07 lb/MMBtu (on a rolling 

average basis of 30 boiler operating 

days) would apply under TWG 

Alternatives A1, A2, A3, or B, EPA 

notes that the operator of NGS may need 

to operate SCR at an emission rate that 

is lower than 0.07 lb/MMBtu depending 

on their compliance with the NOX Cap, 

but the addition of this provision would 

prohibit emissions of NOX, when 

operating with SCR, to exceed 0.07 lb/ 

MMBtu (on a rolling average basis of 30 

boiler operating days). EPA will amend 

the regulatory text accordingly. 

Comment: Omitted ownership 

outcome. 

The TWG stated that the EPA 

described the NGS ownership outcomes 

in a manner that is different from the 

scenarios outlined in the TWG 

Agreement. The commenter indicated 

that the ownership outcomes appear to 

be consistent, except that one potential 

outcome was omitted—the scenario in 

which one or more of the existing NGS 

Participants (LADWP or NV Energy) 

remain in NGS, which would trigger 

Alternative B. 

Response: EPA agrees that we 

inadvertently omitted from 

§ 49.5513(j)(3)(ii)(D) the potential 

scenario where one or both of the 

Departing Participants (i.e., LADWP or 

NV Energy) do not exit NGS as 

expected. EPA is updating the language 

to incorporate the omitted ownership 

possibility. 

Comment: Describe details of TWG 

Agreement more fully in the preamble to 

the Final Rule. 

The TWG expressed concern that EPA 

only briefly described the elements of 

the TWG Agreement in the 

Supplemental Proposal. One member of 

the TWG asserted that the limited 

discussion does not accurately present 

the provisions of the Agreement as it 

relates to clean energy economic 

development for affected Tribes, the 

rigorous development and consideration 

of clean energy alternatives to NGS, 

mitigation of CO2 emissions, and Local 

Benefit Fund to address concerns of the 

public in the vicinity of NGS and the 

Kayenta-Black Mesa Mine Complex. 

Should EPA proceed with this 

alternative in the Final Rule, the 

commenter requested that the Agency 

fully describe the key elements in the 

preamble to the Final Rule. 

Response: EPA acknowledges that the 

TWG Agreement contains additional 

provisions that will be beneficial to the 

tribes in the area and to the 

environment. However, EPA does not 

consider it appropriate to provide a 

detailed discussion of these additional 

provisions of the TWG Agreement in 

our Final Rule. EPA was not a signatory 

to the TWG Agreement and did not 

participate in the TWG Stakeholder 

group. The TWG Agreement speaks for 

itself and the participants and 

signatories are the appropriate entities 

to interpret the provisions of the TWG 

Agreement. EPA is finding that it is 

necessary or appropriate to regulate 

NOX emissions from NGS to reduce 

visibility impairment at the GCNP and 

10 other Class I areas. The other 

measures described by the commenter 

are outside the scope of our authority 

for this action. Therefore, EPA is 

declining to provide any further 

discussion of the provisions in the TWG 

Agreement that go beyond addressing 

regional haze concerns associated with 

NOX emissions from NGS. 

The comment also requests EPA to 

add certain language to the Final Rule. 

Specifically, the comment asks EPA to 

add: ‘‘Nothing in this final rule shall 

preclude the NGS Participants from 

seeking to obtain greenhouse gas 

emission reduction credits, or similar 

commodities associated with activities 

committed to in the TWG Agreement, 

under any Federal or State law or policy 

to the extent permitted under such 

applicable law or policy.’’ 

EPA is also declining to add the 

requested language to our Final Rule. 

EPA is not exercising any authority in 

this action other than implementing the 

BART provisions in CAA section 169A 

and the RHR, through our discretion in 

the TAR. It would be inappropriate in 

this action to take any position on the 

future use or regulation of GHG 

emission reductions or ‘‘similar 

commodities.’’ 

Comment: TWG Alternative meets 

Reasonable Progress requirements. 

One member of the TWG stated that 

the TWG Alternative was intended to 

meet not only BART requirements, but 

also reasonable progress requirements 

applicable to NGS through 2044. The 

commenter requested that EPA 

acknowledge, in the preamble to the 

Final Rule, that the TWG Alternative 

satisfies both the BART and reasonable 

progress requirements of the CAA 

through 2044. 

Response: Today’s final rule 

addresses the NOX BART requirements 

of the RHR for NGS. We have not 

considered whether the TWG 

Alternative meets the reasonable 

progress requirements for NGS. We note 

that EPA has not made any finding 

pursuant to 40 CFR 49.11(a) that it is 

necessary or appropriate at this time to 

promulgate a FIP to meet the reasonable 

progress or other requirements under 

the RHR. The requirement for states to 

develop reasonable progress goals and 

long-term strategies to achieve those 

goals is set out in CAA section 169A 

and 40 CFR 51.308(d). There is no 

requirement that EPA address these 

requirements for sources on the Navajo 

Nation unless EPA makes a 

determination that it is necessary or 

appropriate for EPA to do so. 

Comment: Delete requirement to keep 

records of maintenance. 

One member of the TWG requested 

that EPA delete the requirement that the 

NGS operator keep records of all major 

maintenance activities that occur at 

NGS. According to the commenter, the 

existing title V permit, which requires 

that the operator maintain and operate 

emission control equipment in a manner 

that is consistent with good engineering 

practices to keep emissions at or below 

applicable emissions limitations, 

provides sufficient assurance that 

emission control equipment will be 

operated and maintained in accordance 

with best practices. 

Response: EPA is deleting the 

requirement proposed under 

§ 49.5513(j)(7)(vi) to require the operator 

of NGS to keep records of all major 

maintenance activities at NGS because 

records of major maintenance activities 

are not needed for demonstrating 

compliance with the 2009–2044 or 

2009–2029 NOX Caps or other 

provisions of the TWG Alternative. 

Comment: Require recordkeeping for 

the life of the plant. 

One commenter indicated that the 

requirement to maintain records for 5 

years is insufficient and inappropriate 

for the compliance schedule associated 

with NGS and recommended that 

records be maintained from 2009 

through the remaining operating life of 

the plant. 

Response: EPA agrees that because the 

operator of NGS must ensure 

compliance with the 2009–2044 NOX

Cap, the operator of NGS should also 

maintain records for the life of the 

facility to demonstrate compliance with 

the TWG Alternative. In the regulatory 

language in our Final Rule, EPA is 

amending § 49.5513(j)(7) to require the 

owner or operator of each unit to 

maintain records, as required under 

§ 49.5513(j)(7)(i) to (vi), until the earlier 

of December 22, 2044 or the date that 

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142At the request of the TWG, at their kick-off 

meeting, EPA presented a summary of our Proposed 

Rule and framework for BART Alternatives. The 

presentation at the TWG kick-off meeting was 

generally the same presentation EPA provided to 

other stakeholders. See document 0033 in the 

docket for the rule. 

143See document number 0122 in the docket for 

this rule. 

144See document number 0182 and 0186 in the 

docket for this rule. 

145At the request of the TWG, at their kick-off 

meeting, EPA presented a summary of our Proposed 

Rule and framework for BART Alternatives. The 

presentation at the TWG kick-off meeting was 

generally the same presentation EPA provided to 

other stakeholders. See document 0033 in the 

docket for the rule. 

the owners cease conventional coalfired operation of all units at NGS. 

Comment: Concern that affected 

parties were excluded from TWG. 

Numerous commenters expressed 

frustration that all affected parties were 

not included in the development of the 

TWG Alternative. The Hopi Tribe noted 

that they have a Generating Performance 

Agreement with SRP that should have 

mandated their involvement. The White 

Mountain Apache Tribe also noted that 

it was not party to the TWG Agreement. 

Another commenter noted that 

Executive Order (EO) 13175 requires 

that all tribal nations be consulted on 

these types of regulations, and asserted 

that EPA and DOI violated this EO. 

Another commenter argued that the 

TWG did not include grassroots 

organizations and discouraged their 

participation in TWG public forums. 

One commenter stated that the EPA 

did not give the public enough time to 

comment on the TWG Alternative before 

proposing approval of it and, on that 

basis, demanded that the EPA withdraw 

its proposed approval. The commenter 

added that the TWG Agreement assumes 

that the Hopi will support the Kayenta 

Mine Lease extension when it expires in 

2025, but the Hopi have yet to discuss 

the extension with the 12 Hopi 

independent villages, which is a 

requirement in the Hopi Constitution. 

Furthermore, the commenter noted that 

the TWG Agreement ignores the 

requirement of completing an EIS and 

ROD before the NGS site lease with the 

Navajo Nation expires in 2019. The 

commenter argued that DOI’s signing of 

the TWG Agreement, without the 

fulfillment of these requirements, 

violates NEPA. The commenter added 

that in 1989, the Hopi Tribe rejected the 

Draft Kayenta Mine-Black Mesa Mine 

EIS in its entirety, and implied that the 

decision to accept the TWG proposal 

could compromise EPA’s final decision. 

Response: EPA recognizes that there 

are affected tribes and other 

stakeholders that were not invited to 

participate in the Technical Work 

Group. EPA was not involved in the 

formation of the TWG and not involved 

in any meetings or discussions of the 

TWG.142 As discussed in section 10.0 of 

the Response to Comments document, 

consistent with Executive Order 13175: 

Consultation and Coordination with 

Indian Tribal Governments, EPA 

consulted with tribes early and regularly 

during the development of this 

rulemaking for NGS. We note that the 

Regional Administrator for Region 9 

spoke with Chairman of the Hopi Tribe, 

LeRoy Shingoitewa, on September 13, 

2013 about the TWG Alternative and 

notified elected leaders or legal counsel 

for five tribes when EPA signed the 

Supplemental Proposal. EPA also held 

individual and joint consultation 

meetings with tribal leaders in Phoenix, 

Arizona on December 9 and 10, 2013. 

EPA disagrees that we did not provide 

the public enough time to review the 

TWG Alternative. EPA posted the TWG 

Alternative to the public docket on July 

26, 2013, the same day it was submitted 

to EPA.143 EPA reviewed the TWG 

Alternative and on September 25, 2013, 

signed a Supplemental Proposal that put 

forth the TWG Alternative as an 

additional better than BART alternative 

for public comment. On October 22, 

2013, the Supplemental Proposal was 

published in the Federal Register.144

The public had nearly six months to 

review the TWG Agreement and 

Alternative as submitted to EPA and 

approximately three months to review 

and comment on EPA’s Supplemental 

Proposal. EPA also notes that EPA’s 

rulemaking is not subject to NEPA. 

Comment: EPA’s relationship to the 

TWG is confusing. 

The White Mountain Apache Tribe 

stated that although EPA stated it was 

not involved in the Technical Work 

Group, EPA was a signatory of the ‘‘Joint 

Federal Agency Statement Regarding 

Navajo Generating Station,’’ the scope of 

which includes numerous elements that 

reference EPA’s commitments, along 

with the Departments of the Interior and 

Energy, in relation to NGS. The 

commenter suggests that EPA was 

involved in a legal triangulation with 

the TWG signatories and that such 

action is an extra-jurisdictional exercise 

by EPA, to which the Tribe does not 

consent. The commenter concludes that 

the Tribe cannot consider the TWG 

Alternative unless its published form is 

changed by EPA to fully disentangle the 

proposal from the signatory group and 

all non-BART Agreement terms, and 

additional public comment is thereafter 

allowed. 

Response: We disagree that the Joint 

Federal Agency Statement Regarding 

Navajo Generating Station indicates that 

EPA was involved in the TWG. The 

Joint Federal Agency Statement was 

signed by the Administrator of EPA and 

the Secretaries of the Interior and 

Energy on January 4, 2013. Among other 

things, that document acknowledged 

that each of the three federal agencies 

has an interest in the operation of NGS 

and set forth the goals of the agencies 

with respect to NGS and energy 

production in the region served by NGS. 

Although EPA clearly has an interest 

in reducing the visibility impacts of 

NGS, EPA was not part of the TWG. 

EPA did not participate in any of the 

substantive discussions and 

negotiations of the TWG. Two 

representatives of EPA attended the 

beginning of the first meeting of the 

TWG but only to present a summary of 

EPA’s February 5, 2013 Proposed 

Rule.145 After the initial meeting, EPA 

was not involved with the TWG until 

the TWG Agreement was completed. As 

such, EPA disagrees with the 

commenter that EPA is ‘‘entangled’’ 

with the TWG. 

The TWG was not primarily 

composed of federal agencies. The TWG 

had two Tribes (Gila River Indian 

Community and the Navajo Nation), two 

environmental organizations 

(Environmental Defense Fund and 

Western Resource Advocates), two 

Arizona utilities (CAWCD and SRP) and 

DOI. Appendix B of the TWG 

Agreement contains provisions relating 

to BART but there were several other 

provisions of the TWG Agreement that 

are beyond the scope of BART and are 

not part of EPA’s rulemaking in this 

action. 

For all the above reasons, EPA does 

not agree with the assumption 

underlying the comment that the White 

Mountain Apache Tribe ‘‘cannot 

consider the TWG Alternative unless its 

published form is changed by EPA to 

fully disentangle the proposal from the 

signatory group and all non-BART 

Agreement terms.’’ EPA does not agree 

that any further public comment is 

warranted. 

K. Other BART Alternatives 

Comment: Suggested BART 

Alternative from EarthJustice. 

Despite its objections to the proposed 

BART alternatives, one commenter 

suggested an alternative that includes 

(1) an enforceable requirement that one 

NGS unit shut down by 2020 and (2) an 

enforceable requirement that the 

remaining two units install SCR and 

meet a NOX emission limit of 0.065 lb/ 

MMBtu by the beginning of 2020. The 

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commenter recognized that other 

alternatives may exist, but asserted that 

for any alternative to comply with the 

minimum legal requirements, it must 

produce better visibility outcomes in 

Class I areas than BART and 

demonstrate that it does so through the 

use of visibility modeling. 

Response: Neither the BART 

requirements nor the provisions in the 

RHR governing alternatives to BART 

requires that BART sources cease 

operation. As such, EPA does not 

consider it appropriate for the Agency to 

require the shutdown of one unit of 

NGS by 2020 absent the consent of the 

owners. Regardless of whether the 

suggested alternative would provide for 

earlier and greater visibility 

improvement, it is not an option at this 

time. As explained in this rulemaking, 

the TWG Alternative does comply with 

the legal requirements for BART 

alternatives. 

Comment: Suggested BART 

Alternative from CAP NIA Users: New 

controls should not be required until 

after 2030. 

One commenter presented a table 

purporting to show EPA’s calculations 

of the NOX caps that would apply for a 

range of potential BART emission 

limits: 0.055, 0.06, 0.07, and 0.15 lb/

MMBtu. According to the commenter, 

the NOX cap that would apply under 

limits of 0.06 and 0.07 lb/MMBtu would 

exceed the proposed 2009–2044 NOX

CAP by 2.5 and 7.5 percent, 

respectively. The commenter asserted 

that these differences would have 

imperceptible impacts on visibility and 

that, therefore, the use of the NOX cap 

based on a limit of 0.055 lb/MMBtu 

unduly constrained TWG Alternative A 

and resulted in an unwarranted 

requirement to install SCR on two NGS 

units by 2030, which would impose 

inequitable compliance costs on 

agricultural water users. The commenter 

stated that a NOX cap based on a BART 

limit of 0.06 or 0.07 lb/MMBtu would be 

very similar to the proposed 2009–2044 

NOX Cap, but would provide enough of 

an incremental increase to add 3 years 

of additional compliance flexibility for 

the installation of SCR on two units. 

The same commenter also stated that 

based on the 2009–2044 NOX Cap as 

proposed in the Supplemental Proposal, 

TWG Alternative A contains unused 

‘‘headroom’’ that renders the operation 

of SCR by 2030 unnecessary. According 

to the commenter, TWG Alternative A 

has the effect of forcing NOX emissions 

to a level that is at least 33,000 tons 

below the NOX cap, which the 

commenter believes makes the 

requirement to install and operate SCR 

by 2030 artificially stringent and 

unnecessary, and therefore arbitrary and 

capricious. The commenter indicated 

that the headroom under TWG 

Alternative A1 would yield more than 6 

years of additional compliance 

flexibility for the operation of SCR, and 

TWG Alternatives A2 and A3 would 

yield more than 3 years. The commenter 

concluded that EPA should revise the 

TWG Alternatives to provide the 

maximum amount of compliance 

flexibility for installation of SCR on 

NGS so as to not unnecessarily impose 

costs on NIA water users. 

Response: EPA disagrees with the 

assertion that new controls should not 

be required until after 2030. As stated 

previously, the TWG Agreement was a 

negotiated agreement, submitted to EPA, 

representing diverse interests. EPA 

evaluated the TWG Alternative to 

determine whether it was consistent 

with our framework for better than 

BART alternatives. Thus, although a few 

commenters may believe that the 

timeframes for compliance in the TWG 

Alternative are too stringent, the TWG 

Alternative is consistent with our 

proposed framework and it is consistent 

with the level of control in Appendix B 

to the TWG Agreement, which the 

operator and owners of NGS, as well as 

CAP, two tribes and two environmental 

organizations, have determined is 

acceptable. 

As stated elsewhere in the RTC, we 

disagree with the assertion that BART 

for NGS is an emission limit associated 

with SNCR (0.15 lb/MMBtu) or a less 

stringent limit associated with SCR 

(0.06 or 0.07 lb/MMBtu). Therefore, the 

additional time for compliance 

suggested by the commenters using 

higher BART Benchmarks or NOX Caps 

is not appropriate. The commenters 

further assert that NGS could comply 

with a limit of 0.07 lb/MMBtu in 2032 

and 2033 and still maintain total 

emissions below the 2009–2044 NOX

Cap. EPA disagrees with commenters 

that the ‘‘unused headroom’’ warrants 

additional time to comply with the limit 

of 0.07 lb/MMBtu. The emission 

estimates that EPA presented in our 

Supplemental Proposal for the TWG 

Alternative involved projecting future 

emissions to 2044 based on average heat 

input at NGS over 2001–2008. Heat 

input in the future is expected to be 

variable and could possibly remain 

higher than average over an extended 

period of time, significantly affecting 

the total flexibility or compliance 

margin. EPA’s analysis was provided 

simply to assess whether operation 

consistent with the requirements under 

each TWG Alternative (A1–A3) could 

reasonably be determined to maintain 

emissions below the 2009–2044 NOX

Cap and were not intended to represent 

actual year-by-year emissions in the 

future. Thus, the ‘‘unused headroom’’ is 

theoretical and could be smaller or 

larger than cited by the commenters. 

L. Other Comments 

Comment: Disproportionate impacts 

to tribes. 

The Tonto Apache Tribe and the San 

Carlos Apache Tribe commented that 

both the original BART proposal and the 

proposed TWG Alternative are contrary 

to the obligations of the United States 

and its trust responsibilities to Indian 

Tribes under CAP. The commenters 

stated that both regulatory programs 

would have disproportionate impacts on 

tribes with CAP contracts. The 

commenters noted that environmental 

quality is of utmost importance to the 

tribes, but that clean air is the 

responsibility of all citizens. Therefore, 

the commenters assert that because the 

United States owns 24.3 percent of NGS, 

the costs of compliance for that 24.3 

percent share should be shared among 

all American people, who will benefit 

from cleaner air. The commenters urged 

EPA to develop an alternative regulation 

that does not place additional burden on 

Indian Tribes. 

Response: EPA agrees that our 

proposed BART determination and the 

TWG Alternative will impact tribes with 

CAP water contracts. We note that the 

Joint Federal Agency Statement on NGS 

reflects the U.S. Government’s 

recognition of its responsibilities related 

to NGS and trust responsibility to 

Indian tribes affected by NGS. 

Although EPA is finalizing a BART 

Benchmark for NGS, the regulatory 

requirements of this Final Rule will 

include only the requirements and 

compliance timeframes for the TWG 

Alternative as proposed in our 

Supplemental Proposal. Under the TWG 

Alternative, emission reductions at NGS 

would be achieved in phases, including 

closure of one unit or the equivalent in 

2019, and compliance with an emission 

limit achievable with SCR in 2030. We 

note that the closure of one unit was 

possible because of the planned 

divestment of LADWP and NV Energy 

from NGS by 2019. Because LADWP 

and NV Energy are unrelated to CAP, 

EPA does not expect substantial 

compliance costs to be borne by 

Reclamation (and thus, tribes or other 

CAP water users) due to the first phase 

of emission reductions at NGS in 2019. 

EPA further notes that the 2030 

compliance date for meeting an 

emission limit achievable with SCR on 

two units at NGS is approximately 16 

years from the present day. As stated 

elsewhere in the RTC, the requirements 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46545 

under BART and the TWG Alternative 

include emission limits, rather than 

technology requirements. Thus, 16 years 

from now, although SCR will be capable 

of meeting the emission limit, other 

technologies or options may become 

available for the operator of NGS to 

more cost-effectively meet the NOX

emission limit of 0.07 lb/MMBtu. 

EPA recognized the potential impacts 

to tribes of our proposed BART 

determination and sought ways to 

provide flexibility and a framework for 

affected stakeholders to develop 

alternative approaches to BART. EPA 

has determined that the TWG 

Alternative achieves greater emission 

reductions than would otherwise be 

achieved under our BART 

determination, while providing 

additional time for compliance. This 

additional time allows the DOI, DOE, 

and EPA time to work with tribal 

stakeholders to identify and implement 

strategies for achieving the goals 

outlined in the Joint Federal Agency 

Statement on NGS. 

Comment: EPA lacks authority to 

regulate NGS 

Several commenters indicated that 

EPA overstepped its authority and 

stated that EPA’s proposal hinders the 

state’s ability to deal with 

environmental issues on a local level. 

One commenter stated that EPA’s 

regulations are an attack on free 

enterprise, and believes that the agenda 

of the current administration is to ban 

all coal-fired power plants regardless of 

the economic effect. 

Response: EPA disagrees that it has 

overstepped its regulatory authority and 

disagrees that any State has authority to 

regulate air pollution from sources 

located on the Navajo reservation. EPA’s 

authority to regulate NGS is established 

in sections 301(a) and 301(d)(4) of the 

CAA and the TAR. Section 301(d)(4) 

authorizes EPA to directly administer 

provisions of the CAA in Indian country 

under certain circumstances. The State 

of Arizona lacks authority to regulate air 

pollution sources located on the Navajo 

reservation. 

EPA disagrees that the regulations 

promulgated in this action, which are 

requirements consistent with the TWG 

Agreement, constitutes an attack on free 

enterprise. The TWG Alternative was 

submitted to EPA by a stakeholder 

group that had determined it was a more 

cost-effective approach to continuing to 

operate NGS than a prior proposal by 

EPA. EPA considered the direct costs of 

compliance in our five-factor BART 

analysis, and although not specifically 

required in the BART Guidelines, EPA 

also considered numerous indirect 

impacts and costs in our analysis of 

Factor 2. The comment provides no 

information other than conclusory 

statements that EPA failed to adequately 

consider the cost of compliance. EPA 

also disagrees that there is any agenda 

or effort to ban coal burning electricity 

generation. The TWG Agreement, as 

agreed upon by the members of the 

TWG, includes a provision that specifies 

continued operation of NGS as a 

conventional coal-fired power plant 

until 2044 when its lease with the 

Navajo Nation expires. Therefore, this 

rulemaking does not constitute a ban on 

burning coal. 

Comment: Lack of Consultation with 

Tribes. 

The Navajo Nation commented that 

EPA should improve communication at 

the start of any rulemakings to ensure 

that the Navajo Nation can provide 

meaningful information. The 

commenter said that even when the 

Agency develops supporting rule 

information like the RIA the Navajo 

Nation would like to be involved as it 

could impact the Nation. The 

commenter pointed out that EPA has 

known for decades that the Navajo 

Nation would be impacted by regulation 

of NGS and FCPP. The commenter 

quoted excerpts from Executive Order 

13175—Consultation and Coordination 

with Indian Tribal Governments and 

said that the standard for determining if 

a regulation has tribal implication is not 

whether it ‘‘impose[s] substantial direct 

compliance costs on tribal 

governments,’’ but rather a regulation 

has ‘‘substantial direct effects on one or 

more Indian tribes.’’ 

The Navajo Nation stated that it was 

not consulted during the development 

of the ANPR and indicated that in 

August of 2009, one day prior to the 

ANPR for NGS and FCPP, EPA made a 

courtesy call to the President of the 

Navajo Nation. The Navajo Nation 

believes that if early and meaningful 

consultation with the Nation had 

occurred this could have led to an 

adequate analysis of BART controls and 

careful examination of non-air quality 

impacts. 

The Gila River Indian Community 

expressed similar concerns regarding 

the lack of consultation. During a 

consultation on August 7, 2012, the 

commenter stated that it was their 

understanding that EPA would describe 

to the Community the proposed 

regulation prior to the rulemaking being 

issued. Instead, the commenter said, 

EPA called the night before issuing the 

rule, which the commenter said was 

inadequate and inconsistent with the 

expectations regarding consultation. 

The commenter also understood that the 

rule was to be proposed in September 

2012 but it was not proposed until 

January 2013 and in the meantime 

several stakeholders provided 

additional input to the Agency. 

However, the Community was not 

consulted during this time. In addition, 

the Community expects an explanation 

of the final rule after it is issued by EPA. 

The Hopi Tribe also commented on 

the lack of consultation and 

involvement of tribes in developing the 

regulation. The commenter submitted 

multiple letters to EPA indicating its 

concern about not being involved in the 

development of the rule or consulted 

but without providing pertinent 

information. In one of the letters, the 

commenter said that the government 

acknowledged the Hopi Tribe as a 

stakeholder and the intention to work 

with the Tribe; however, contrary to 

statements in the Joint Federal Agency 

Statement on NGS to work with tribes, 

the Hopi Tribe was not included in the 

TWG. 

The Hopi Tribe specifically indicated 

that it was denied information regarding 

the TWG Alternative and the 

development of the alternative, 

something the commenter pointed out is 

essential in order to provide relevant 

and useful comments to EPA. The 

commenter said that it has submitted 

two Freedom of Information Act (FOIA) 

requests to DOI, which included 

documentation related to NGS and 

information documenting DOI’s 

representation of the Hopi Tribe during 

the negotiation of the TWG Alternative. 

The commenter said that until it has the 

information requested via FOIA, it is not 

able to provide written comments on the 

TWG Alternative. 

The Hopi Tribe asserted that it is has 

been treated differently than other tribal 

stakeholders in the TWG Agreement. 

For example, the TWG Agreement states 

that SRP will advocate to EPA the 

Navajo Nation’s treatment as state (TAS) 

status. The Hopi Tribe indicated that the 

TWG Alternative protects the economic 

interests of the Navajo Nation and the 

Gila Indian Community but 

compromises the coal revenues of the 

Hopi Tribe and contains no mitigation 

measures for the significant and adverse 

economic impact. The Hopi Tribe 

indicated that it will be 

disproportionately and adversely 

affected by the reduced capacity at NGS. 

The Kaibab Band of Paiute Indians 

expressed similar concerns regarding 

the lack of involvement of Indian Tribes 

and demanded that EPA consider the 

requests of the Kaibab Paiute. The 

commenter referred to the TWG 

Agreement and requested that the 

Kaibab Paiute Indian Reservation 

receive $2.5 million of the $5 million 

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146http://www.gpo.gov/fdsys/pkg/WCPD-2000-11- 

13/pdf/WCPD-2000-11-13-Pg2806-2.pdf. 

147See listed item indicating consultation 

meeting on June 10, 2009 between Laura Yoshii, 

Acting Regional Administrator of EPA Region 9, 

and President Joe Shirley, Jr., of the Navajo Nation, 

to discuss moving forward on the ANPR for Four 

Corners Power Plant and NGS. See document titled 

‘‘2013_0109 Timeline of all tribal consultations on 

NGS.docx’’ in document number 0005 in the docket 

for this rule. 

148See 74 FR 44313 at 44314 (August 28, 2009). 

149See document titled ‘‘2013_0109 Timeline of 

all tribal consultation on NGS.pdf’’ in document 

number 0005 in the docket for the rule at and 

document titled ‘‘Updated Timeline of all Tribal 

Consultation on NGS_for Final Rule.pdf’’ in the 

docket for the rule. 

150 Id., and see, e.g., document 0008 in the docket 

for the rule. 

151See page 25 and 26 of the TSD to the Proposed 

Rule, document 0014 in the docket for this rule. 

152See document titled ‘‘Updated Timeline of all 

Tribal Consultation on NGS_for Final Rule.pdf’’ in 

the docket for the rule. 

153 Id. 

154See comment numbers 0340, 0317, 0387, 0402, 

0419, and 0421 in the docket for the rule. 

155See comment number 0440 in the docket for 

the rule. 

156See document titled ‘‘2014_0107 EPA Letter to 

Chairman Honanie with Enclosure 1.pdf’’ in the 

docket for this rule. 

Local Benefit Fund designated for 

community projects within 100 miles of 

NGS (the reservation is 60 miles from 

NGS). Also, the commenter said that the 

TWG Agreement promotes the 

development of clean energy, and based 

on that provision of the agreement, the 

commenter requested a 250 MW solar 

farm. 

The Tohono O’odham Nation objected 

that a number of Indian nations that 

would be substantially affected by the 

rule were excluded from the TWG. The 

commenter noted that it is particularly 

concerned with maintaining CAP water 

delivery under whatever rule is 

finalized by EPA. 

Response: EPA understands the 

importance of NGS to numerous tribes 

located in Arizona and the importance 

of our trust responsibility to Indian 

tribes affected by NGS. As a result, we 

have attempted to ensure that these 

tribes were consulted throughout the 

rulemaking process. We respectfully 

disagree that there was a lack of 

consultation with tribes. 

EPA agrees with the Navajo Nation 

that Executive Order 13175 defines 

‘‘policies that have tribal implications’’ 

to refer to regulations or other actions 

that have substantial direct effects on 

one or more Indian tribes.146 We 

disagree that EPA’s discussion of direct 

compliance costs on tribal governments 

is not a correct standard for 

consideration and note that section 5(b) 

of EO 13175 further states that 

To the extent practicable and permitted by 

law, no agency shall promulgate any 

regulation that has tribal implications, that 

imposes substantial direct compliance costs 

on Indian tribal governments, and that is not 

required by statute . . . 

In our discussion of EO 13175, we 

included consideration of substantial 

direct compliance costs to tribal 

governments, as well as the broader 

consideration of substantial direct 

effects on one or more Indian tribes. We 

conclude that our proposed action on 

NGS will have tribal implications and 

may have substantial indirect effects on 

tribes, but will not impose substantial 

direct compliance costs on Indian tribal 

governments. We also conclude that this 

rule is appropriate under the CAA 

because NGS is a facility that is subject 

to BART. 

In our proposed rule, EPA provided a 

document that listed all written or 

telephone correspondence as well as 

consultation meetings between EPA and 

Tribes on NGS. Although the 

commenter suggests that EPA’s 

telephone call to the President of the 

Navajo Nation one day prior to the 

signature of the ANPR in August 2009 

was our first communication with the 

Nation on the subject, we note that the 

timeline includes a meeting between 

EPA and the Navajo Nation that 

occurred two months prior to the ANPR 

to discuss EPA’s plans to move forward 

on an ANPR related to our ongoing 

BART analyses for FCPP and NGS.147

EPA further notes that the ANPR was 

not a proposed rule. The ANPR was an 

Advanced Notice of Proposed 

Rulemaking where we provided the 

public advance notice of our intention 

to develop rulemakings for FCPP and 

NGS. EPA included some initial 

analysis of two of the BART factors and 

stated that the ‘‘specific purpose of this 

ANPR is for EPA to collect additional 

information.’’ 148 Subsequent to the 

publication of the ANPR in the Federal 

Register on August 28, 2009, and prior 

to our proposed rule on NGS, EPA held 

four consultation meetings with tribes 

in 2009, eight consultation meetings 

with tribes in 2010, eight consultation 

meetings in 2011, and ten consultation 

meetings with tribes in 2012.149 Of these 

meetings, at least eight were held as 

group consultation sessions where all 

tribes in Arizona were invited to 

participate and were provided the 

opportunity to request individual 

consultation meetings as well.150

The Navajo Nation, the Hopi Tribe, 

the Gila River Indian Community, the 

Tohono O’odham Nation, the Ak-Chin 

Indian Community, the Pascua Yaqui 

Tribe, the Fort McDowell Yavapai 

Nation, and the Yavapai-Apache Nation, 

and the Inter Tribal Council of Arizona 

submitted comments to EPA on the 

ANPR. EPA summarized and provided 

responses to comments received from 

tribal governments in the TSD for our 

proposed rule on NGS.151 The primary 

concerns expressed by the tribal 

governments related to the economic 

importance of NGS and the relationship 

of NGS with CAP and Indian Water 

Settlement Agreements. The Navajo 

Nation also commented on specific 

aspects of the five-factor analysis for 

BART, and the Hopi Tribe submitted an 

economic study it had commissioned 

that expresses concern that regulatory 

actions would force NGS to close. In our 

proposed rule and in our development 

of our proposed framework for BART 

Alternatives, including the credit for 

early installation of LNB/SOFA, EPA 

recognized the importance of NGS to 

tribes in Arizona, both in contributing to 

the economies of the Navajo Nation and 

Hopi Tribe, and in serving as a source 

of electrical power for CAP and a source 

of revenue to the Lower Colorado River 

Basin Development Fund, as related to 

water settlement agreements with 

numerous tribes in Arizona. Based on 

this recognition, EPA put forth 

additional options for greater flexibility 

in the compliance timeframe and 

invited stakeholders to develop and 

submit additional BART Alternatives to 

EPA for consideration. 

Following the publication of our 

proposed rule on February 5, 2013, EPA 

engaged in 17 consultation meetings 

with tribes prior to the January 2014 

close of the public comment period.152

Of these meetings, at least two were 

held as group consultation sessions 

where all tribes in Arizona were invited 

to participate and were provided the 

opportunity to request individual 

consultation meetings as well.153 EPA 

received comment letters on our 

proposal and Supplemental Proposal 

from the Navajo Nation, the Gila River 

Indian Community, the Tohono 

O’odham Nation, the Ak-Chin Indian 

Community, the Tonto Apache Tribe, 

the San Carlos Apache Tribe, and the 

Kaibab Band of Paiute Indians.154 At the 

request of two tribes for additional time 

beyond January 6, 2014 to submit 

comments, EPA agreed that we would 

consider comments from tribal 

governments submitted after the close of 

the comment period. The White 

Mountain Apache Tribe submitted 

comments on February 5, 2014.155 In 

addition, in response to their request to 

EPA for information related to NGS, we 

provided responsive documents to the 

Hopi Tribe on January 7, 2014.156 As 

shown in additional correspondence, 

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157See document titled ‘‘2014_0131 Letter from 

Chairman Honanie.pdf’’ and document titled 

‘‘2014_0206 EPA Response to Chairman Honanie_

Hopi Tribe.pdf’’ in the docket for this rule. 

158The EPA policy on Consultation and 

Coordination with Indian Tribes is posted on the 

following Web site: http://www.epa.gov/tribal/

consultation/consult-policy.htm. 

159See Appendix A (List of Written Comments) 

to the RTC and the docket for this rulemaking. 

the Hopi Tribe requested additional 

time to submit comments, and EPA 

again agreed to consider late comments 

from the Hopi Tribe.157 EPA did not 

receive any further comments from the 

Hopi Tribe. 

Several tribes also expressed concern 

that the Technical Work Group included 

only two tribes, the Navajo Nation and 

the Gila River Indian Community, and 

excluded numerous other tribes that 

also have a significant economic interest 

in NGS. EPA recognizes that many 

tribes were not included in the 

development of the TWG Agreement. 

EPA was not involved in the formation 

of the TWG or any of the negotiations 

between the members of the TWG in 

developing the TWG Agreement. In 

addition, our evaluation of the TWG 

Agreement was for the sole purpose of 

determining whether Appendix B to the 

TWG Agreement meets our framework 

for a ‘‘better than BART’’ Alternative. 

Therefore, although EPA agrees that 

many tribes have economic interest in 

NGS and CAP, EPA does not have any 

role in the distribution of funds 

described in the TWG Agreement. 

Based on numerous consultation 

meetings between high-level officials 

from EPA and elected tribal leaders, 

beginning in 2009 and extending into 

2013, and our development of flexible 

options for BART Alternatives in 

response to comments from tribes, EPA 

considers our consultation on NGS to be 

consistent with EO 13175 and EPA’s 

policy to engage in early and 

meaningful consultation with tribes.158

EPA will provide notification of our 

Final Rule, in writing, to all tribal 

governments that submitted comments 

to EPA on our Proposed Rule or 

Supplemental Proposal and will provide 

our written responses to their specific 

comments. All written correspondence 

from tribal governments to EPA 

regarding NGS and our proposed BART 

determination is available in the docket 

for this rulemaking.159

V. Summary of Final Action 

On February 5, 2013, EPA issued a 

proposed BART analysis of NOX

controls at NGS. Based on that analysis, 

EPA proposed a NOX emission limit of 

0.055 lb/MMBtu for all three units 

within five years of a Final Rule. Our 

proposed rule also set out a framework 

for evaluating BART alternatives at 

NGS. EPA proposed a ‘‘better than 

BART’’ alternative (Alternative 1), 

consistent with this proposed 

framework, requiring compliance with a 

NOX emission limit of 0.055 lb/MMBtu 

on one unit per year in 2021, 2022, and 

2023. EPA invited stakeholders to 

submit additional alternatives, 

consistent with our proposed framework 

for ‘‘better than BART’’ alternatives, to 

EPA for consideration. 

On July 26, 2013, a stakeholder group, 

known as the TWG, submitted an 

agreement among seven diverse entities 

(TWG Agreement) that included an 

additional BART alternative (Appendix 

B to the TWG Agreement). In general, 

this alternative includes closure of one 

unit at NGS, or curtailment of net 

generating capacity by an equivalent 

amount, in 2019 and compliance with 

an emission limit of 0.07 lb/MMBtu on 

two units at NGS in 2030. The TWG 

Agreement also included a provision 

requiring the owners of NGS to cease 

conventional coal-fired generation at 

NGS by the end of 2044. EPA 

independently evaluated Appendix B to 

the TWG Agreement to determine 

whether it complied with the framework 

we put forth in our Proposed Rule, as 

well as the statutory and regulatory 

requirements in the CAA and the RHR. 

On October 22, 2013, EPA published 

a Supplemental Proposal. Our 

Supplemental Proposal contained a 

detailed evaluation of Appendix B to 

the TWG Agreement along with a 

discussion of our legal rationale for 

proposing to approve requirements 

consistent with the TWG Agreement as 

a ‘‘better than BART’’ alternative. Our 

Supplemental Proposal and this Final 

Rule refer to our regulations that are 

generally consistent with Appendix B to 

the TWG Agreement as the ‘‘TWG 

Alternative.’’ The Supplemental 

Proposal (i.e., the TWG Alternative) 

included regulatory requirements to 

achieve substantial NOX reductions over 

time, as well as a cap in cumulative 

NOX emissions from NGS over 2009– 

2044 (2009–2044 NOX Cap) to ensure 

that lifetime emissions from NGS under 

the TWG Alternative do not exceed 

lifetime emissions that would have 

otherwise occurred under our proposed 

BART determination for NGS (BART 

Benchmark). 

Based on our review of all comments 

we received on the Proposed Rule and 

Supplemental Proposal, EPA is taking 

action to finalize requirements 

consistent with the TWG Agreement, as 

a ‘‘better than BART’’ Alternative (TWG 

Alternative) put forth in our 

Supplemental Proposal. EPA is also 

taking final action to determine that a 

BART Benchmark, consistent with our 

proposed BART determination, is 

appropriate for establishing the 2009– 

2044 NOX Cap under the TWG 

Alternative. EPA is not finalizing our 

proposed BART determination for NGS 

in the regulatory requirements of this 

Final Rule, and EPA is not taking action 

to finalize Alternative 1, the ‘‘better than 

BART’’ Alternative we put forth in our 

Proposed Rule. 

This Final Action is expected to result 

in over an 80 percent reduction in NOX

emissions and to significantly reduce 

the impact of NGS on visibility at 11 

mandatory Class I Federal areas. EPA’s 

action to finalize requirements 

consistent with the TWG Agreement as 

a ‘‘better than BART’’ alternative for 

NGS will ensure that lifetime NOX

emissions from NGS do not exceed the 

BART Benchmark. 

VI. Administrative Requirements 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action will finalize a sourcespecific FIP for a single generating 

source. This type of action is exempt 

from review under Executive Orders 

12866 (58 FR 51735, October 4, 1993) 

and 13563 (76 FR 3821, January 21, 

2011). 

B. Paperwork Reduction Act 

This action does not impose an 

information collection burden under the 

provisions of the Paperwork Reduction 

Act, 44 U.S.C. 3501 et seq. Under the 

Paperwork Reduction Act, a ‘‘collection 

of information’’ is defined as a 

requirement for ‘‘answers to . . . 

identical reporting or recordkeeping 

requirements imposed on ten or more 

persons. . . .’’ 44 U.S.C. 3502(3)(A). 

Because the final FIP applies to a single 

facility, Navajo Generating Station, the 

Paperwork Reduction Act does not 

apply. See 5 CFR 1320(c). 

Burden means the total time, effort, or 

financial resources expended by persons 

to generate, maintain, retain, or disclose 

or provide information to or for a 

Federal agency. This includes the time 

needed to review instructions; develop, 

acquire, install, and utilize technology 

and systems for the purposes of 

collecting, validating, and verifying 

information, processing and 

maintaining information, and disclosing 

and providing information; adjust the 

existing ways to comply with any 

previously applicable instructions and 

requirements; train personnel to be able 

to respond to a collection of 

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46548 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

information; search data sources; 

complete and review the collection of 

information; and transmit or otherwise 

disclose the information. 

An agency may not conduct or 

sponsor, and a person is not required to 

respond to a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for EPA’s regulations in 40 

CFR are listed in 40 CFR Part 9. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) 

generally requires an agency to prepare 

a regulatory flexibility analysis of any 

rule subject to notice and comment 

rulemaking requirements under the 

Administrative Procedure Act or any 

other statute unless the agency certifies 

that the rule will not have a significant 

economic impact on a substantial 

number of small entities. Small entities 

include small businesses, small 

organizations, and small governmental 

jurisdictions. 

For purposes of assessing the impacts 

of today’s rule on small entities, small 

entity is defined as: (1) A small business 

as defined by the Small Business 

Administration’s (SBA) regulations at 13 

CFR 121.201; (2) a small governmental 

jurisdiction that is a government of a 

city, county, town, school district or 

special district with a population of less 

than 50,000; and (3) a small 

organization that is any not-for-profit 

enterprise which is independently 

owned and operated and is not 

dominant in its field. 

After considering the economic 

impacts of this action on small entities, 

I certify that this final action will not 

have a significant economic impact on 

a substantial number of small entities. 

The Navajo Generating Station is not a 

small entity and the FIP for Navajo 

Generating Station being finalized today 

does not impose any compliance 

requirements on small entities. See MidTex Electric Cooperative, Inc. v. FERC, 

773 F.2d 327 (D.C. Cir. 1985). We 

recognize that several tribes located in 

Arizona have expressed concerns 

regarding potential indirect effects of 

this Final Rule; however, these indirect 

effects are not direct compliance costs 

or requirements on small entities. 

D. Unfunded Mandates Reform Act 

(UMRA) 

This rule will impose an enforceable 

duty on the private sector owners of 

Navajo Generating Station. However, 

this rule does not contain a Federal 

mandate that may result in expenditures 

of $100 million (in 1996 dollars) or 

more for State, local, and tribal 

governments, in the aggregate, or the 

private sector in any one year. EPA’s 

estimate for the total annual cost to 

install and operate SCR on all three 

units at NGS if it had been required to 

comply with BART does not exceed 

$100 million (in 1996 dollars) in any 

one year. Because we are finalizing 

requirements consistent with Appendix 

B to the TWG Agreement, which 

provides more flexibility than EPA’s 

proposed BART determination and 

would, at most, require installation and 

operation of SCR on two units, rather 

than three units at NGS, EPA expects 

the total annual cost of implementing 

the TWG Alternative to also not exceed 

$100 million (in 1996 dollars). Thus, 

this rule is not subject to the 

requirements of sections 202 or 205 of 

UMRA. This action 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. This 

rule will not impose direct compliance 

costs on the Navajo Nation, and will not 

preempt Navajo law. This final action 

will reduce the emissions of NOX from 

a single source, the Navajo Generating 

Station. 

E. Executive Order 13132: Federalism 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the States, on the 

relationship between the national 

government and the States, or in the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. This final action 

requires emission reductions of NOX at 

a specific stationary source located in 

Indian country. Thus, Executive Order 

13132 does not apply to this action. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

Subject to the Executive Order 13175 

(65 FR 67249, November 9, 2000) EPA 

may not issue a regulation that has tribal 

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 tribal governments, or 

EPA consults with tribal officials early 

in the process of developing the 

proposed regulation and develops a 

tribal summary impact statement. EO 

13175 defines ‘‘policies that have tribal 

implications’’ to refer to regulations or 

other actions that have substantial direct 

effects on one or more Indian tribes. 

EPA has concluded that this Final 

Action will have tribal implications 

based on the direct relationship between 

NGS and the Navajo Nation. In addition, 

EPA anticipates that the following direct 

and indirect effects may result from the 

TWG Alternative and Reclamation’s 

ownership interest in NGS: Decreased 

revenues to the Hopi Tribe and the 

Navajo Nation associated with the 

closure of one unit or curtailment of 

electricity generation in 2019; and 

increased water costs to tribes 

associated with the installation of 

controls to meet an emission limit of 

0.07 lb/MMBtu in 2030. However, it 

will neither pre-empt Tribal law nor 

impose substantial direct compliance 

costs on tribal governments (no tribal 

government is an owner or participant 

in NGS and therefore no tribal 

government will be required to pay 

direct costs of compliance). We note 

that the Navajo Nation has the option to 

purchase up to a 170 MW share of NGS 

in 2019. EPA understands that the 

Navajo Nation has not yet made its 

decision and therefore, currently, no 

tribal government is a Participant in 

NGS. 

The owners of NGS, together with the 

Navajo Nation, the Gila River Indian 

Community, and several other 

stakeholders, submitted the TWG 

Agreement to EPA that would provide 

compliance flexibility to the owners and 

result in greater reasonable progress 

than BART toward the national 

visibility goal. This TWG Alternative 

involves closure or curtailment of 

production on one unit of NGS and 

installation of add-on pollution controls 

to the remaining two units. EPA issued 

a Supplemental Proposal proposing to 

find that the TWG Alternative met the 

requirements of the CAA and RHR. 

Today, EPA is finalizing requirements 

consistent with the TWG Agreement. 

Because the TWG Alternative involves 

the closure or curtailment of production 

on one unit and an associated decline in 

the amount of coal mined and 

combusted, to the extent that taxes or 

royalties paid to the Hopi Tribe and the 

Navajo Nation by the operators of 

Navajo Generating Station and the 

Kayenta Mine, are tied to the amount of 

coal that is mined or the amount of 

electricity that is generated at NGS, the 

revenues to the Hopi Tribe and Navajo 

Nation may be expected to decline. In 

addition, under the TWG Alternative, 

when the installation of add-on 

pollution controls occurs in 2030, EPA 

expects the CAWCD variable OM&R 

water rate to increase, affecting tribes 

with allocations of CAP water. 

EPA consulted with tribal officials 

early in the process of developing this 

regulation to permit them to have 

meaningful and timely input into its 

development. EPA first put forth an 

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160See Joint Federal Agency Statement Regarding 

Navajo Generating Station, dated January 4, 2013, 

in the docket for this proposed rulemaking. 

161See Factor 2 analysis, 78 FR 8281–8284 

(February 5, 2013). 

162 Id. 

163 Id. at 8291. 

164 Id. at 8289. 

165As described in our Supplemental Proposal 

(78 FR 62512, October 22, 2013), the seven elements 

of the TWG Agreement were (1) a description of a 

‘‘Reasonable Progress Alternative to BART’’ 

(Appendix B to the TWG Agreement); (2) a study 

of options by Reclamation for replacing the federal 

share of energy being generated from NGS with lowemitting energy; (3) commitments by Interior to 

reduce or offset emissions of carbon dioxide (CO2) 

by three percent per year and facilitate the 

development of clean energy resources; (4) 

commitments by Interior to mitigate potential 

impacts from EPA’s final BART rule to Affected 

Tribes; (5) a commitment by Interior to carry out the 

Phase 2 Study by the National Renewable Energy 

Laboratory (NREL) for the purposes of studying 

options for the future of NGS; (6) a commitment by 

SRP to make funds available for a Local Benefit 

Fund for community improvement projects within 

100 miles of NGS or the Kayenta Mine; and (7) a 

summary of obligations of the Parties to the 

Agreement and miscellaneous legal provisions. 

166See document titled ‘‘Updated Timeline of All 

Tribal Consultations on NGS for Final Rule.docx’’ 

in the docket for this rulemaking. 

167See document titled ‘‘Updated Timeline of all 

Tribal Consultation on NGS_for Final Rule.pdf’’ in 

the docket for the rule. 

168 Id. 

ANPR on August 28, 2009 to accept 

comment on preliminary information 

provided by FCPP and NGS and to begin 

the consultation process with the 

Federal Land Managers and affected 

tribes. 

EPA received numerous comments on 

the ANPR from tribes and tribal 

organizations, including the Navajo 

Nation, Hopi Tribe, Gila River Indian 

Community, Ak-Chin Indian 

Community, Tohono O’odham Nation, 

Pascua Yaqui Tribe, Fort McDowell 

Yavapai Nation, Yavapai-Apache 

Nation, and the Inter Tribal Council of 

Arizona. Comments from the Navajo 

Nation on NGS and from the Hopi Tribe 

focused on the significant contribution 

of coal-related royalties, taxes, and 

employment at NGS and the Kayenta 

Mine to the economies of the Navajo 

Nation and the Hopi Tribe. Comments 

from the Gila River Indian Community, 

the Tohono O’odham Nation, and other 

tribes located in Arizona focused on the 

importance of continued operation of 

NGS as a source of power to CAP, in 

order for the federal government to meet 

obligations under existing water 

settlement agreements. The importance 

to tribes of continued operation of NGS 

and affordable water costs cannot be 

overemphasized. 

Given the extent of federal and tribal 

interests in NGS and the federal 

government’s trust responsibility to 

Indian tribes, on January 4, 2013, EPA, 

DOI, and DOE signed a joint federal 

agency statement committing to 

collaborate on several short- and longterm goals, including analyzing and 

pursuing strategies for providing clean, 

affordable and reliable power, affordable 

and sustainable water, and sustainable 

economic development to key 

stakeholders who currently depend on 

NGS.160 The partner agencies have 

already begun to work together with 

stakeholders to identify and undertake 

actions that support implementation of 

BART, including seeking funding to 

cover expenses for pollution control or 

other necessary upgrades for the federal 

portion of NGS. The agencies have also 

begun work to jointly support a phase 

2 report to analyze a full range of clean 

energy options for NGS. Finally, the 

agencies intend to work with 

stakeholders to develop a roadmap for 

achieving long-term, innovative clean 

energy solutions for NGS. 

In our February 5, 2013 Proposed 

Rule, EPA exercised discretion to 

include in our analysis of Factor 2 

(Energy and Non-Air Quality Impacts), 

an examination of the viability of 

continued operation of NGS if new NOX

controls are required, to address the 

concern expressed by numerous tribes 

that a BART determination requiring 

SCR would force NGS to close. Our 

analysis showed that although SCR 

would increase the cost of electricity 

generation at NGS, installing and 

operating SCR at NGS would still be less 

costly than replacing NGS with power 

purchased from elsewhere in the 

West.161 However, we also recognized 

that the timing of regulatory compliance 

is an important consideration given 

potential ownership changes and other 

requirements related to the extension of 

the NGS lease and other rights-of-way 

agreements. As part of our Factor 2 

analysis, we also estimated potential 

water rate increases to tribes.162 As 

discussed in our proposed rule, EPA 

considers the potential economic 

impacts to tribes to argue for flexibility 

in the compliance timeframe for NGS. 

In addition to our proposed BART 

determination for NGS, EPA also 

proposed a framework for evaluating 

alternatives to BART that provide 

options for flexibility in achieving 

emission reductions at NGS. EPA 

proposed an alternative to BART 

consistent with our proposed framework 

and invited stakeholders to submit other 

alternatives to BART that reduce NOX

emissions at NGS while providing longterm, sustainable benefits for tribes.163

We noted that the extended timeframe 

for compliance would not, in itself, 

avoid or mitigate increases in water 

rates for tribes located in Arizona; 

however, it would provide time for the 

collaborating federal agencies to explore 

options to avoid or minimize potential 

impacts to tribes, including seeking 

funding to cover the expenses for the 

federal portion of pollution control at 

NGS.164

Following our Proposed Rule, the 

TWG, which included the Navajo 

Nation, the Gila River Indian 

Community, and the Interior, together 

with four additional groups, submitted 

their agreement (TWG Agreement) that 

contained an additional BART 

alternative for consideration (Appendix 

B to the TWG Agreement). Although 

EPA was not part of the TWG, we note 

that the TWG Agreement included 

seven elements, including elements 

directly or indirectly related to tribes, 

i.e., commitments by Interior to mitigate 

potential impacts from EPA’s final 

BART rule to Affected Tribes and a 

commitment by SRP to make funds 

available for a Local Benefit Fund for 

community improvement projects 

within 100 miles of NGS or the Kayenta 

Mine.165

EPA has met with tribes on numerous 

occasions to discuss the significance of 

NGS to tribal economies and tribal 

water interests in Arizona.166

Consultations with tribes included 

potential economic impacts associated 

with a BART determination for NGS, as 

well as potential impacts from EPA’s 

Mercury and Air Toxics Standards 

(MATS) rulemaking. 

In recognition of the unusual 

complexity of regulating NGS, 

representatives from EPA, including the 

Assistant Administrator and the Deputy 

Assistant Administrator for the Office of 

Air and Radiation and the Regional 

Administrator for Region 9, visited NGS 

and affected communities in the area. 

EPA officials have also met with 

additional stakeholders, at various 

locations, including EPA offices in San 

Francisco, California and Washington, 

DC, and offices of individual tribal 

governing councils and the Inter Tribal 

Council of Arizona. 

Following the publication of our 

proposed rule on February 5, 2013, EPA 

engaged in 17 consultation meetings 

with tribes prior to the January 2014 

close of the public comment period.167

Of these meetings, at least two were 

held as group consultation sessions 

where all tribes in Arizona were invited 

to participate and were provided the 

opportunity to request individual 

consultation meetings as well.168 EPA 

received comment letters on our 

proposal and Supplemental Proposal 

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46550 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

169See comment numbers 0340, 0317, 0387, 0402, 

0419, and 0421 in the docket for the rule. 

170See comment number 0440 in the docket for 

the rule. 

171See document titled ‘‘2014_0107 EPA Letter to 

Chairman Honanie with Enclosure 1.pdf’’ in the 

docket for this rule. 

172See document titled ‘‘2014_0131 Letter from 

Chairman Honanie.pdf’’ and document titled 

‘‘2014_0206 EPA Response to Chairman Honanie_

Hopi Tribe.pdf’’ in the docket for this rule. 

173EPA’s policy on Consultation and 

Coordination with Indian Tribes is posted on the 

following Web site: http://www.epa.gov/tribal/

consultation/consult-policy.htm. 

from the Navajo Nation, the Gila River 

Indian Community, the Tohono 

O’odham Nation, the Ak-Chin Indian 

Community, the Tonto Apache Tribe, 

the San Carlos Apache Tribe, and the 

Kaibab Band of Paiute Indians.169 At the 

request of two tribes for additional time 

beyond January 6, 2014 to submit 

comments, EPA exercised our discretion 

to accept comments from tribal 

governments after the close of the 

comment period. The White Mountain 

Apache Tribe submitted comments on 

February 5, 2014.170 In addition, in 

response to their request to EPA for 

information related to NGS, we 

provided responsive documents to the 

Hopi Tribe on January 7, 2014.171 As 

shown in additional correspondence, 

the Hopi Tribe requested additional 

time to submit comments, and EPA 

continued to exercise our discretion to 

accept late comments from the Hopi 

Tribe.172 Our separate response to 

comments document contains a 

summary of all substantive comments 

and EPA’s responses to those comments. 

Several tribes expressed concern that 

the Technical Work Group included 

only two tribes, the Navajo Nation and 

the Gila River Indian Community, and 

excluded numerous other tribes that 

also have a significant economic interest 

in NGS. Several tribes also asserted that 

the Proposed Rule and Supplemental 

Proposal have disproportionate impacts 

on tribes with CAP water settlements 

and urged EPA to develop an alternative 

regulation that does not place an 

additional burden on Indian tribes. 

Another tribe requested that a portion of 

the funds identified in the TWG 

Agreement be designated to their tribe. 

EPA recognizes that many tribes did 

not participate in the development of 

the TWG Agreement. EPA was not 

involved in the formation of the 

Technical Work Group or any of the 

negotiations between the members of 

the TWG in developing the TWG 

Agreement. In addition, our evaluation 

of the TWG Agreement was for the sole 

purpose of determining whether the 

TWG Alternative (Appendix B to the 

TWG Agreement) meets our framework 

for a ‘‘better than BART’’ Alternative. 

Therefore, although EPA agrees that 

many tribes have economic interests in 

NGS and CAP, EPA did not have a role 

in the TWG Agreement and does not 

have any role in the distribution of 

funds described in the TWG Agreement. 

EPA recognizes that our final action 

will have tribal implications. Because 

we are taking action to finalize 

requirements consistent with the TWG 

Agreement, EPA anticipates that 

increases in CAP water costs as a result 

of the installation of new air pollution 

controls at NGS would not occur until 

2030. In addition, as stated elsewhere, 

EPA has committed to collaborating 

with other federal agencies to explore 

options to avoid or minimize potential 

impacts to tribes, including seeking 

funding to cover the expenses for the 

federal portion of pollution control at 

NGS. 

In summary, EPA has taken numerous 

steps, as described in the preceding 

paragraphs, to evaluate the potential 

impacts on Tribes and to identify and 

provide the flexibility for others to 

develop alternative approaches that 

would meet the requirements of the 

CAA and the RHR while being as 

sensitive as possible to concerns raised 

by Tribes. Through the Joint Federal 

Agency Statement on NGS, the federal 

government has recognized its 

obligations through its trust 

responsibility and through its specific 

historical and ongoing involvement 

with NGS and water rights settlements 

with Tribes. That agreement reflects our 

commitment to ongoing engagement 

with affected Tribes and to the pursuit 

of a long-term solution for electricity 

generation that is protective of the 

economic interests of Tribes and public 

health and the environment. 

Based on numerous consultation 

meetings between high-level officials 

from EPA and elected tribal leaders, 

beginning in 2009 and extending into 

2013, and our development of flexible 

options for BART Alternatives in 

response to comments from tribes, EPA 

considers our consultation on NGS to be 

consistent with EO 13175 and EPA’s 

policy to engage in early and 

meaningful consultation with tribes.173

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

Executive Order 13045: Protection of 

Children from Environmental Health 

Risks and Safety Risks (62 FR 19885, 

April 23, 1997), applies to any rule that: 

(1) Is determined to be economically 

significant as defined under Executive 

Order 12866, and (2) concerns an 

environmental health or safety risk that 

EPA has reason to believe may have a 

disproportionate effect on children. If 

the regulatory action meets both criteria, 

the Agency must evaluate the 

environmental health or safety effects of 

the planned rule on children, and 

explain why the planned regulation is 

preferable to other potentially effective 

and reasonably feasible alternatives 

considered by the Agency. 

This rule is not subject to Executive 

Order 13045 because it requires 

emissions reductions of NOX from a 

single stationary source. Because this 

action only applies to a single source 

and is not a rule of general applicability, 

it is not economically significant as 

defined under Executive Order 12866, 

and does not have a disproportionate 

effect on children. However, to the 

extent that the rule will reduce 

emissions of NOX, which contributes to 

ozone formation, the rule will have a 

beneficial effect on children’s health by 

reducing air pollution that causes or 

exacerbates childhood asthma and other 

respiratory issues. 

H. Executive Order 13211: Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not subject to Executive 

Order 13211 (66 FR 28355 (May 22, 

2001)), because it is not a significant 

regulatory action under Executive Order 

12866. 

I. National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (NTTAA), Public Law 104– 

113, 12 (10) (15 U.S.C. 272 note) directs 

EPA to use voluntary consensus 

standards (VCS) in its regulatory 

activities unless to do so would be 

inconsistent with applicable law or 

otherwise impractical. VCS are 

technical standards (e.g., materials 

specifications, test methods, sampling 

procedures and business practices) that 

are developed or adopted by the VCS 

bodies. The NTTAA directs EPA to 

provide Congress, through annual 

reports to OMB, with explanations 

when the Agency decides not to use 

available and applicable VCS. 

Consistent with the NTTAA, the 

Agency conducted a search to identify 

potentially applicable VCS. For the 

measurements listed below, there are a 

number of VCS that appear to have 

possible use in lieu of the EPA test 

methods and performance specifications 

(40 CFR Part 60, Appendices A and B) 

noted next to the measurement 

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174See, for example, document number 0232 in 

the ANPR docket at EPA–R09–OAR–2009–0598, 

and document numbers 0008 and 0009 in the 

docket for this rule at EPA–R09–OAR–2013–0009. 

175See, for example, document number 0150, 

0152, 0166, 0173, 0302, and 0303 in the docket for 

this rule. 

176See document number 0122 in the docket for 

this rulemaking. 

177See document numbers 0182, 0183, and 0184 

in the docket for this rulemaking. 

178EPA engaged with the government of the Hopi 

Tribe to search for an oral interpreter between 

English and the Hopi language, but the Hopi Tribe 

was unable to locate anyone to provide those 

services. 

179See document 0219 in the docket for this 

rulemaking. 

requirements. It would not be practical 

to specify these standards in the current 

rulemaking due to a lack of sufficient 

data on equivalency and validation and 

because some are still under 

development. However, EPA’s Office of 

Air Quality Planning and Standards is 

in the process of reviewing all available 

VCS for incorporation by reference into 

the test methods and performance 

specifications of 40 CFR Part 60, 

Appendices A and B. Any VCS so 

incorporated in a specified test method 

or performance specification would 

then be available for use in determining 

the emissions from this facility. This 

will be an ongoing process designed to 

incorporate suitable VCS as they 

become available. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order 12898 (59 FR 7629, 

February 16, 1994), establishes federal 

executive policy on environmental 

justice. Its main provision directs 

federal agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. 

EPA has determined that this final 

rule will not have disproportionately 

high and adverse human health or 

environmental effects on minority or 

low-income populations because it 

increases the level of environmental 

protection for all affected populations 

without having any disproportionately 

high and adverse human health or 

environmental effects on any 

population, including any minority or 

low-income population. 

EPA recognizes that numerous 

commenters have stated that this 

rulemaking has environmental justice 

implications because NGS, which is 

among the largest coal-fired power 

plants in the country, is located on the 

Navajo Nation. Commenters have also 

expressed concern that the documents 

associated with this rule are too 

technical for community members to 

understand. Some commenters have 

also argued that EPA should apply the 

same standard to NGS as other coalburning power plants (e.g., Four Corners 

Power Plant), and that the extended 

compliance timeframe for NGS is an 

environmental justice issue. 

Fair treatment and meaningful 

involvement are critical components of 

environmental justice and EPA takes 

fair treatment and meaningful 

involvement seriously. We provided 

numerous opportunities for tribal 

governments, environmental and tribal 

non-governmental organizations, and 

other interested stakeholders to provide 

input in the development of our 

Proposed Rule, Supplemental Proposal, 

and Final Rule for NGS. 

As discussed in more detail in the 

RTC, EPA began our public involvement 

process for a BART determination for 

NGS in 2009, when we published an 

Advanced Notice of Proposed 

Rulemaking (ANPR). During 2009 

through 2012, EPA met with various 

stakeholders, including tribal 

governments and Navajo environmental 

groups to discuss NGS and hear 

concerns related to a BART 

determination for this facility.174 During 

the 11-month comment period for our 

Proposed Rule, EPA continued to meet 

with stakeholders to discuss our 

proposed BART determination for NGS 

and our framework for ‘‘better than 

BART’’ alternatives.175

On July 26, 2013, the TWG submitted 

the TWG Agreement to EPA for 

consideration. EPA posted the TWG 

Agreement to our docket on the same 

day to provide the public an 

opportunity to review it.176 On 

September 25, 2013, EPA posted a 

Supplemental Proposal, along with 

supporting documents, to the docket to 

allow for early review by interested 

parties.177 The Supplemental Proposal 

was published in the Federal Register 

on October 22, 2013. The comment 

period for the Supplemental Proposal 

closed on the same day as the BART 

proposal, on January 6, 2014. The 

Supplemental Proposal also included 

notice of five open house and public 

hearing events EPA scheduled 

throughout Arizona in November 2013. 

The open houses allowed members of 

the public an opportunity to talk with 

representatives from EPA and ask 

questions. EPA held events at the 

LeChee Chapter House, located on the 

Navajo Nation, as well as in Page, 

Arizona, and provided oral 

interpretation services between English 

and Dine ́ (the Navajo language). EPA 

also held an event at the Hopi Day 

School, located in Kykotsmovi, the seat 

of the Hopi tribal government.178

Finally, we also held events in Phoenix 

and in Tucson, Arizona, to allow 

stakeholders in central and southern 

Arizona, representing CAP water 

interests and several tribes receiving 

CAP water, the opportunity to provide 

comment and talk with representatives 

from EPA. 

EPA understands that the TSD and 

Federal Register notices include 

technical information that may be 

difficult to understand. EPA provided 

Fact Sheets and handouts, written in 

plain language, at the open house and 

public hearing events.179 EPA 

representatives were also present at the 

events to discuss and explain our 

Proposals. 

EPA recognizes that some 

commenters may view the timeframe for 

compliance under EPA’s framework for 

BART Alternatives as an environmental 

justice issue. We note that the Navajo 

Nation and other Tribes expressed 

concern with the potential economic 

impacts of this rulemaking. The 

flexibility we provided has allowed for 

a balance between these considerations. 

We further note that the LNB/SOFA 

credit, an important component of the 

timeframe under our ‘‘better than 

BART’’ framework, was based on real, 

actual emission reductions beginning in 

2009 that were voluntary and not 

required by any rule or regulation. We 

also note that the TWG Alternative, 

which calls for closure of one unit in 

2019 (or equivalent curtailment), will 

result not only in reductions of NOX, 

but also reductions of several other 

pollutants, including SO2, PM, CO2, and 

hazardous air pollutants. Although the 

compliance date of emission limit for 

two units (achievable with the 

installation of SCR) under the TWG 

Alternative is in 2030, over 2009 to 

2044, the TWG Alternative will result in 

greater NOX reductions than would have 

been achieved under BART, will result 

in step-wise reductions of NOX and 

additional pollutants that affect 

visibility or human health, and will 

provide an enforceable mechanism to 

ensure that NGS ceases conventional 

coal-fired electricity generation at NGS 

by the end of 2044. All of these 

measures will increase the level of 

environmental protection for 

communities affected by NGS. 

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46552 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

K. Congressional Review Act 

The Congressional Review Act, 5 

U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement 

Fairness Act of 1996, generally provides 

that before a rule may take effect, the 

agency promulgating the rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States. Section 804 

exempts from section 801 the following 

types of rules (1) rules of particular 

applicability; (2) rules relating to agency 

management or personnel; and (3) rules 

of agency organization, procedure, or 

practice that do not substantially affect 

the rights or obligations of non-agency 

parties. 5 U.S.C. 804(3). EPA is not 

required to submit a rule report 

regarding today’s action under section 

801 because this action is a rule of 

particular applicability. This rule 

finalizes a source-specific FIP for a 

single generating source. 

L. Petitions for Judicial Review 

Under section 307(b)(1) of the Clean 

Air Act, petitions for judicial review of 

this action must be filed in the United 

States Court of Appeals for the 

appropriate circuit by October 7, 2014. 

Filing a petition for reconsideration by 

the Administrator of this final rule does 

not affect the finality of this rule for the 

purposes of judicial review nor does it 

extend the time within which a petition 

for judicial review may be filed, and 

shall not postpone the effectiveness of 

such rule or action. This action may not 

be challenged later in proceedings to 

enforce its requirements. See CAA 

section 307(b)(2). 

List of Subjects in 40 CFR Part 49 

Environmental protection, 

Administrative practice and procedure, 

Air pollution control, Indians, 

Intergovernmental relations, Reporting 

and recordkeeping requirements. 

Dated: July 28, 2014. 

Gina McCarthy, 

Administrator. 

Title 40, chapter I of the Code of 

Federal Regulations is amended as 

follows: 

PART 49—INDIAN COUNTRY: AIR 

QUALITY PLANNING AND 

MANAGEMENT 

■ 1. The authority citation for part 49 

continues to read as follows: 

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

■ 2. Section 49.5513 is amended by 

adding paragraph (j) to read as follows: 

§ 49.5513 Federal Implementation Plan 

Provisions for Navajo Generating Station, 

Navajo Nation. 

* * * * * 

(j)(1) Applicability. Regional Haze 

Best Available Retrofit Technology 

limits for NOX for this plant are in 

addition to the requirements of 

paragraphs (a) through (i) of this section. 

The provisions of this paragraph (j) are 

severable, and if any provision of this 

paragraph (j), or the application of any 

provision of this paragraph (j) to any 

owner/operator or circumstance, is held 

invalid, the application of such 

provision to other owner/operators and 

other circumstances, and the remainder 

of this paragraph (j), will not be affected 

thereby. Nothing in this paragraph (j) 

allows or authorizes any Unit to emit 

NOX at a rate that exceeds its existing 

emission limit of 0.24 lb/MMBtu as 

established by EPA permit AZ 08–01 

issued on November 20, 2008. 

(2) Definitions. Terms not defined 

below have the meaning given to them 

in the Clean Air Act or EPA’s 

regulations implementing the Clean Air 

Act and in paragraph (c) of this section. 

For purposes of this paragraph (j): 

(i) 2009–2029 NOX Cap means a limit 

on emissions from Units 1, 2, and 3 of 

no more than 416,865 tons of NOX.

(ii) 2009–2044 NOX Cap means a limit 

on emissions from Units 1, 2, and 3 of 

no more than 494,899 tons of NOX.

(iii) Boiler 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 

steam-generating unit. It is not 

necessary for fuel to be combusted the 

entire 24-hour period. 

(iv) Coal-fired unit means any of Units 

1, 2, or 3 at Navajo Generating Station. 

(v) Continuous Emission Monitoring 

System or CEMS means the equipment 

required by 40 CFR part 75 and this 

paragraph (j). 

(vi) Departing Participant means 

either Los Angeles Department of Water 

and Power or Nevada Energy, also 

known as NV Energy or Nevada Power 

Company. 

(vii) Emission limitation or emission 

limit means the federal emissions 

limitation required by this paragraph. 

(viii) Existing Participant means the 

existing owners of NGS: Los Angeles 

Department of Water and Power; 

Nevada Energy, also known as NV 

Energy or Nevada Power Company; Salt 

River Project Agricultural Improvement 

and Power District; Arizona Public 

Service Company; and Tucson Electric 

Company, together with the United 

States, acting through the Bureau of 

Reclamation. 

(ix) lb means pound(s). 

(x) Low-NOX Burners and Separated 

Over-Fire Air or LNB/SOFA means 

combustion controls installed on each 

Unit between 2009 and 2011. 

(xi) Navajo Nation means the Navajo 

Nation, a federally recognized Indian 

Tribe. 

(xii) NGS or Navajo Generating 

Station means the steam electric 

generating station located on the Navajo 

Reservation near Page, Arizona, 

consisting of Units 1, 2, and 3, each 750 

MW (nameplate rating), the switchyard 

facilities, and all facilities and 

structures used or related thereto. 

(xiii) NOX means nitrogen oxides 

expressed as nitrogen dioxide (NO2). 

(xiv) Owner/operator means any 

person(s) who own(s) or who operate(s), 

control(s), or supervise(s) one more of 

the Units of the Navajo Generating 

Station. 

(xv) MMBtu means million British 

thermal unit(s). 

(xvi) Operating hour means any hour 

that fossil fuel is fired in the unit. 

(xvii) Unit means any of Units 1, 2, or 

3 at Navajo Generating Station. 

(xviii) Valid data means CEMs data 

that is not out of control as defined in 

40 CFR part 75. 

(3) ‘‘Better than BART’’ alternative for 

NOX. Total cumulative NOX emissions 

from Units 1, 2, and 3, from January 1, 

2009 to December 31, 2044, may not 

exceed the 2009–2044 NOX Cap. The 

owner/operator must implement the 

applicable operating scenario, under 

paragraph (j)(3)(i) of this section, to 

ensure NOX emission reductions 

sufficient to maintain total cumulative 

NOX emissions from Units 1, 2, and 3 

below the 2009–2044 NOX Cap. 

(i) Operating scenarios to comply with 

2009–2044 NOX Cap. The owner/ 

operator must comply with one of the 

following operating scenarios based on 

the applicability provisions in 

paragraph (j)(3)(ii) of this section. 

(A) Alternative A1. (1) By December 

31, 2019, the owner/operator must 

permanently cease operation of one 

coal-fired Unit; and 

(2) By December 31, 2030, the owner/ 

operator must comply with a NOX

emission limit of 0.07 lb/MMBtu, based 

on a rolling average of 30 boiler 

operating days, on each of the two 

remaining coal-fired Units. 

(3) The owner/operator must 

permanently cease operation of Units 1, 

2, and 3 if total cumulative emissions of 

NOX from Units 1, 2, and 3, based on 

annual reports required under 

paragraph (j)(4)(ii) of this section, 

exceed the 2009–2044 NOX Cap at any 

time prior to December 31, 2044. 

(B) Alternative A2. (1) By December 

31, 2019, the owner/operator must 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46553 

permanently cease operation of one 

coal-fired Unit; and 

(2) By December 31, 2019, the owner/ 

operator may increase net generating 

capacity of the remaining two coal-fired 

Units by a combined total of no more 

than 189 MW. The actual increase in net 

generating capacity shall be limited by 

the sum of 19 MW and the ownership 

interest, in net MW capacity, purchased 

by the Navajo Nation by December 31, 

2019. Nothing in paragraph (j) of this 

section alters any regulatory 

requirements, including those for preconstruction permitting, associated with 

any increase in the net generating 

capacity of the Unit(s). 

(3) By December 31, 2030, the owner/ 

operator must comply with a NOX

emission limit of 0.07 lb/MMBtu, based 

on a rolling average of 30 boiler 

operating days, on each of the two 

remaining coal-fired Units. 

(4) The owner/operator must 

permanently cease operation of Units 1, 

2, and 3 if total cumulative emissions of 

NOX from Units 1, 2, and 3, based on 

annual reports required under 

paragraph (j)(4)(ii) of this section, 

exceed the 2009–2044 NOX Cap at any 

time prior to December 31, 2044. 

(C) Alternative A3. (1) By December 

31, 2019, the owner/operator must 

reduce the net generating capacity of 

NGS by no less than 561 MW. The 

actual reduction in net generating 

capacity of NGS shall be determined by 

the difference between 731 MW and the 

ownership interest, in net MW capacity 

and limited to 170 MW, purchased by 

the Navajo Nation by December 31, 

2019. 

(2) By December 31, 2030, the owner/ 

operator must comply with a NOX

emission limit of 0.07 lb/MMBtu, based 

on a rolling average of 30 boiler 

operating days, on two Units. 

(3) The owner/operator must 

permanently cease operation of Units 1, 

2, and 3 if total cumulative emissions of 

NOX from Units 1, 2, and 3, based on 

annual reports required under 

paragraph (j)(4)(ii) of this section, 

exceed the 2009–2044 NOX Cap at any 

time prior to December 31, 2044. 

(D) Alternative B. (1) Total cumulative 

NOX emissions from Units 1, 2, and 3 

may not exceed the 2009–2044 NOX Cap 

or the 2009–2029 NOX Cap. 

(2) The owner/operator must cease 

operation of Units 1, 2, and 3 if total 

cumulative emissions of NOX from 

Units 1, 2, and 3, based on annual 

reports required under paragraph 

(j)(4)(ii) of this section, exceed the 

2009–2029 NOX Cap at any time prior 

to December 31, 2029. The owner/

operator may restart operation of Units 

1, 2, and 3 after January 1, 2030, as long 

as total cumulative emissions of NOX

from Units 1, 2, and 3, based on annual 

reports required under paragraph 

(j)(4)(ii) of this section, do not exceed 

the 2009–2044 NOX Cap. 

(3) The owner/operator must 

permanently cease operation of Units 1, 

2, and 3 if total cumulative emissions of 

NOX from Units 1, 2, and 3, based on 

annual reports required under 

paragraph (j)(4)(ii)), exceed the 2009– 

2044 NOX Cap at any time prior to 

December 31, 2044. 

(ii) Applicability of alternatives. (A) 

Alternative A1 applies if by December 

31, 2019, one of the following occurs: 

(1) Both of the Departing Participants 

retire their ownership interests in NGS 

by December 31, 2019, and the Navajo 

Nation does not purchase an ownership 

interest in NGS; or 

(2) Both of the Departing Participants 

sell their ownership interests in NGS to 

Existing Participants, and the Navajo 

Nation does not purchase an ownership 

interest in NGS; or 

(3) One of the Departing Participants 

retires its ownership interest in NGS 

and the other Departing Participant sells 

its ownership interest in NGS to an 

Existing Participant, and the Navajo 

Nation does not purchase an ownership 

interest in NGS. 

(B) Alternative A2 applies if by 

December 31, 2019, one of the following 

occurs: 

(1) Both of the Departing Participants 

sell their ownership interests in NGS to 

Existing Participants, the Navajo Nation 

has purchased an ownership interest in 

NGS, and the owner/operator has 

increased net generating capacity of the 

two remaining Units by a combined 

total of no more than 189 MW; or 

(2) One of the Departing Participants 

retires its ownership interest in NGS 

and the other Departing Participant sells 

its ownership interest in NGS to an 

Existing Participant, the Navajo Nation 

has purchased an ownership interest in 

NGS, and the owner/operator has 

increased net generating capacity of the 

two remaining Units by a combined 

total of no more than 189 MW. 

(C) Alternative A3 applies if by 

December 31, 2019, one of the following 

occurs: 

(1) Both of the Departing Participants 

sell their ownership interests in NGS to 

Existing Participants, the Navajo Nation 

has purchased an ownership interest in 

NGS, and the owner/operator has not 

increased net generating capacity of the 

Units at NGS; or 

(2) One of the Departing Participants 

retires its ownership interest in NGS 

and the other Departing Participant sells 

its ownership interest in NGS to an 

Existing Participant, the Navajo Nation 

has purchased an ownership interest in 

NGS, and the owner/operator has not 

increased net generating capacity of the 

Units at NGS. 

(D) Alternative B applies if, by 

December 31, 2019, if one of the 

following occurs: 

(1) Any of the Departing Participants 

sell their ownership interests in NGS to 

a Party other than the Navajo Nation 

that is not an Existing Participant, or 

(2) Any of the Departing Participants 

remains as a participant in NGS. 

(iii) By December 22, 2044, the 

owner/operator shall permanently cease 

conventional coal-fired electricity 

generation by all coal-fired Units at 

NGS. 

(4) Reporting and implementation 

requirements for BART. (i) No later than 

December 1, 2019, the owner/operator 

must notify EPA of the applicable 

Alternative for ensuring compliance 

with the 2009–2044 NOX Cap. 

(ii) Beginning in 2015, and annually 

thereafter until the earlier of December 

22, 2044 or the date on which the 

owner/operator ceases conventional 

coal-fired electricity generation by all 

coal-fired Units at NGS, the owner/

operator must report to EPA, the annual 

heat input, the annual emissions of 

sulfur dioxide, carbon dioxide, and NOX

from the previous full calendar year. In 

addition, the owner/operator must also 

report total cumulative emissions of 

NOX from NGS to assure compliance 

with the 2009–2044 NOX Cap and the 

2009–2029 NOX Cap (if applicable). The 

owner/operator must make this report 

available to the public, either through a 

link on its Web site or directly on its 

Web site. The report must be made 

available within 30 days of the 

submittal deadline associated with the 

annual emission inventory required by 

the Part 71 Operating Permit for NGS. 

(iii) No later than December 31, 2020, 

the owner/operator must submit an 

application to revise its existing Part 71 

Operating Permit to incorporate the 

requirements and emission limits of the 

applicable Alternative to BART under 

paragraph (j)(3) of this section. The Part 

71 Operating Permit for NGS must 

incorporate practically enforceable 

limits for NOX of 0.24 lb/MMBtu, on a 

30-day rolling average basis, for each 

Unit equipped with LNB/SOFA, and 

0.07 lb/MMBtu, on a rolling average 

basis of 30 boiler operating days, for 

each Unit equipped with SCR, as 

federally enforceable permit conditions. 

(iv) In addition to the requirements of 

paragraphs (j)(4)(i), (ii) and (iii) of this 

section, if Alternative B applies, the 

owner/operator must submit annual 

Emission Reduction Plans to the 

Regional Administrator. 

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46554 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 

(A) No later than December 31, 2019 

and annually thereafter through 

December 31, 2028, the owner/operator 

must submit an Emission Reduction 

Plan containing anticipated year-by-year 

emissions from Units 1, 2, and 3 

covering the period from 2020 to 2029 

that will assure that the operation of 

NGS will result in emissions of NOX

that do not exceed the 2009–2029 NOX

Cap. The Emission Reduction Plan may 

contain several potential operating 

scenarios and must set forth the past 

annual actual emissions and the 

projected emissions for each potential 

operating scenario. Each potential 

operating scenario must demonstrate 

compliance with the 2009–2029 NOX

Cap. The Emission Reduction Plan shall 

identify emission reduction measures 

that may include, but are not limited to, 

the installation of advanced emission 

controls, a reduction in generation 

output, or other operating strategies 

determined by the owner/operator. The 

owner/operator may revise the potential 

operating scenarios set forth in the 

Emission Reduction Plan, provided the 

revised plan ensure that NOX emissions 

remain below the 2009–2029 NOX Cap. 

(B) No later than December 31, 2029 

and annually thereafter, the owner/

operator shall submit an Emission 

Reduction Plan containing year-by-year 

emissions covering the period from 

January 1, 2030 to December 31, 2044 

that will assure that the operation of 

NGS will result in emissions of NOX

that do not exceed the 2009–2044 NOX

Cap. The Emission Reduction Plan shall 

identify emission reduction measures 

that may include, but are not limited to, 

the installation of advanced emission 

controls, a reduction in generation 

output, or other operating strategies 

determined by the owner/operator. The 

owner/operator may revise the potential 

operating scenarios set forth in the 

Emission Reduction Plan, provided the 

revised plan ensure that NOX emissions 

remain below the 2009–2044 NOX Cap. 

(C) The requirement to submit annual 

Emission Reduction Plans beginning no 

later than December 31, 2019, shall be 

incorporated into the Part 71 Operating 

Permit for NGS as federally enforceable 

permit conditions. 

(5) Continuous emission monitoring 

system (CEMS). (i) At all times, the 

owner/operator of each unit must 

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. All hourly valid data will be used 

to determine compliance with the 

emission limitations for NOX in 

paragraph (j)(3) of this section for each 

unit. If the CEMs data is not valid, that 

CEMs data shall be treated as missing 

data and not used to calculate the 

emission average. CEMs data does not 

need to be bias adjusted as defined in 

40 CFR part 75. Each required CEMS 

must obtain valid data for at least 90 

percent of the unit operating hours, on 

an annual basis. 

(ii) The owner/operator of each unit 

shall comply with the quality assurance 

procedures for CEMS found in 40 CFR 

part 75. In addition to these Part 75 

requirements, relative accuracy test 

audits shall be calculated for both the 

NOX pounds per hour measurement and 

the heat input measurement. The 

calculation of NOX pounds per hour and 

heat input relative accuracy shall be 

evaluated each time the CEMS undergo 

relative accuracy testing. 

(6) Compliance determination for NOX

emission limits. (i) Compliance with the 

NOX emission limits under paragraphs 

(j)(3)(i) of this section shall be 

determined on a rolling average basis of 

thirty (30) Boiler Operating Days on a 

unit by unit basis. Compliance shall be 

calculated in accordance with the 

following procedure: Sum the total 

pounds of NOX emitted from the Unit 

during the current Boiler Operating Day 

and the previous twenty-nine (29) Boiler 

Operating Days; sum the total heat input 

to the Unit in MMBtu during the current 

Boiler Operating Day and the previous 

twenty-nine (29) Boiler Operating Days; 

and divide the total number of pounds 

of NOX by the total heat input in 

MMBtu during the thirty (30) Boiler 

Operating Days. A new 30 Boiler 

Operating Day rolling average shall be 

calculated for each new Boiler 

Operating Day. Each 30 Boiler Operating 

Day rolling average shall include all 

emissions that occur during periods 

within any Boiler Operating Day, 

including emissions from startup, 

shutdown, and malfunction. 

(ii) If a valid NOX pounds per hour or 

heat input is not available for any hour 

for a Unit, that heat input and NOX

pounds per hour shall not be used in the 

calculation for that 30 boiler operating 

day period. 

(7) Recordkeeping. The owner/

operator of each Unit must maintain the 

following records until the earlier of 

December 22, 2044 or the date that 

conventional coal-fired operation of all 

units at NGS permanently ceases: 

(i) All CEMS data, including the date, 

place, and time of sampling or 

measurement; parameters sampled or 

measured; and results as required by 

Part 75 and as necessary to calculate 

each units pounds of NOX and heat 

input for each hour. 

(ii) Each Boiler Operating Day rolling 

average emission rate for NOX

calculated in accordance with paragraph 

(j)(6)(i) of this section. 

(iii) Each unit’s 30 Boiler Operating 

Day pounds of NOX and heat input. 

(iv) 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. 

(v) Records of the relative accuracy 

calculation of the NOX lb/hr 

measurement and hourly heat input. 

(vi) Any other records required by 40 

CFR part 75. 

(8) Reporting. All reports and 

notifications under this paragraph (j) 

must be submitted to the Director, 

Navajo Environmental Protection 

Agency, P.O. Box 339, Window Rock, 

Arizona 86515, and to the Director of 

Enforcement Division, U.S. EPA Region 

IX, at 75 Hawthorne Street, San 

Francisco, CA 94105. 

(i) The owner/operator must notify 

EPA within two weeks after completion 

of installation of NOX control 

technology on any of the units subject 

to this section. 

(ii) Within 30 days after the first 

applicable compliance date in 

paragraph (j)(3) of this section and 

within 30 days of every second calendar 

quarter thereafter (i.e., semi-annually), 

the owner/operator must submit a report 

that lists for each calendar day, 

calculated in accordance with paragraph 

(j)(6) of this section, total lb of NOX and 

heat input (as used to calculate 

compliance per paragraph (j)(6) of this 

section, for each unit’s last 30 boiler 

operating days. The owner/operator 

must include the results of the last 

relative accuracy test audit and the 

calculated relative accuracy for lb/hr 

NOX and heat input performed 45 days 

prior to the end of that reporting period. 

The end of the year report shall also 

include the percent valid data for each 

NOX, diluent, and flow monitor used in 

the calculations of compliance with 

paragraph (j)(6) of this section. 

(9) Enforcement. Notwithstanding any 

other provision in this implementation 

plan, any credible evidence or 

information relevant as to whether the 

unit would have been in compliance 

with applicable requirements if the 

appropriate performance or compliance 

test had been performed, can be used to 

establish whether or not the owner or 

operator has violated or is in violation 

of any standard or applicable emission 

limit in the plan. 

(10) Equipment operations. At all 

times, including periods of startup, 

shutdown, and malfunction, the owner/ 

operator shall, to the extent practicable, 

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Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations 46555 

maintain and operate the unit including 

associated air pollution control 

equipment in a manner consistent with 

good air pollution control practices for 

minimizing emissions. Determination of 

whether acceptable operating and 

maintenance procedures are being used 

will be based on information available 

to the Regional Administrator, or their 

designee, which may include, but is not 

limited to, monitoring results, review of 

operating and maintenance procedures, 

and inspection of the unit. 

(11) Affirmative defense. The 

affirmative defense provisions of 

paragraphs (c)(2) and (i) of this section 

do not apply to this paragraph (j). 

[FR Doc. 2014–18228 Filed 8–7–14; 8:45 am] 

BILLING CODE 6560–50–P 

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