# 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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1 For 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 ProtectionAgency (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 (NO X ) 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 NO X from NGS over 2009–2044 (2009–2044

NO X 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 NO X 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 NO X in order to reduce the impact NGS has on visibility at 11 mandatory Class I Federal areas. We are finalizingan 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 NO X from NGS by establishing a long-term facility-wide cap on total NO X 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 NO X 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 NO X emission reductions at lower cost than BART in exchange for flexibility in the timeframe for achieving NO X reductions. When fully implemented, this Final Rule requires over an 80 percent reduction in NO X 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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2 See 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.

3 See 78 FR 8274 (February 5, 2013) and 78 FR 62509 (October 22, 2013).

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

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

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

7 See 74 FR 44314 (August 28, 2009); 78 FR 8279 (February 5, 2013); see also 56 FR 50172 (October 3, 1991) addressing BART for SO 2 based on Reasonably Attributable Visibility Impairment. 8 See 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).

12 See 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).

13 See 40 CFR 49.11(a).

14 See 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.’’ 6NGS 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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15 Because of its complicated history and its location on the Navajo Nation, NGS faces numerous unique complexities and the unusual requirementto 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).

19 See 74 FR 44314 (August 28, 2009). 20 See 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 NO X 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 NO X emission credit for the previous early and voluntary
installation of low-NO X 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 NO X 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 EPAattended 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 NO X emission limit
of 0.07 lb/MMBtu on two units at NGS beginning in 2030. The TWG Agreement


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27 See 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 NO X 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 NO X 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 NO X . 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 NO X emissions. 28 Based on these changes, EPA proposed a 2009–2044 NO X 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 NO X Cap in this manner is easier to apply and enforce in the context of a cap in NO X 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 NO X 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 NO X 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 NO X emissions cap over the period of 2009– 2029 (2009–2029 NO X Cap) that is equivalent to emission reductions thatwould be achieved by a more welldefined operating scenario. The 2009–

2029 NO X Cap would apply in addition
to the 2009–2044 NO X 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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31 See Ariz. Public Serv. Co. v. EPA, 562 F.3d
1116 (10th Cir. 2009).

32 Id. 33 The combination of the 2009–2044 and 2009–

2029 NO X Caps under TWG Alternative B means
that if NGS exceeds the 2009–2029 NO X 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 NO X 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 NO X emission reductions required by the BART provisions of the CAA and RHR. EPA is determining that our proposed NO X 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 NO X 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 NO X 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 NO X 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

NO X Cap, the operator of NGS must also
ensure that cumulative NO X emissions over 2009–2029 comply with the 2009–

2029 NO X Cap. The 2009–2029 NO X 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 NO X from NGS exceed the

2009–2044 NO X 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 NO X exceed the 2009–2029 NO X 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 NO X do not
exceed the 2009–2029 NO X Cap and the

2009–2044 NO X 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—S UMMARY OF THE 

### M AJOR 

### R EGULATORY 

### P ROVISIONS OF THE 

### TWG A LTERNATIVE

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 increasecapacity 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 NO X Cap of 494,899 tons.

• Permanently cease operation of all units if cumulative emissions before 2044 exceed 2009–2044 NO X Cap.


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

34 See 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. 35 We 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—S UMMARY OF THE 

### M AJOR 

### R EGULATORY 

### P ROVISIONS OF THE 

### TWG A LTERNATIVE

### —Continued

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

Additional Emission Cap ... • n/a • Comply with 2009–2029
NO X 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 NO X Cap.

• By 12/31/30 meet NO X

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 NO X 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 NO X

.

• 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 ReductionPlans to project year-byyear emissions to assure compliance with
NO X Caps.

* All units must comply with the existing NO X 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 NO X exceed
the 2009–2029 NO X 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 NO X exceed
the 2009–2044 NO X 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

NO X 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 NO X 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 NO X 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 controlequipment, and CEMS because recordkeeping of maintenance activities are not needed to ensure compliance with
the 2009–2029 and 2009–2044 NO X 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.


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

36 See final action for the previous FIP for NGS at 75 FR 10179 (March 5, 2010).

37 NRDC 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).

39 See 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). 40 See 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

NO X 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 areawhere 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 NO X 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


### 46521 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

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

42 Id. and 78 FR 62509 (October 22, 2013). 43 Emissions 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).

44 http://www.epa.gov/climatechange/basics/.

45 http://www.epa.gov/climatechange/
EPAactivities.html.

46 See http://www2.epa.gov/carbon-pollutionstandards.

47 For more information, please see www.ngskmceis.net.

48 http://www.epa.gov/otaq/.

49 See, 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 NO X 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 NO X 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 tocut 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, NO X , 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


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

50 See Fact Sheet for Tier 3 Standards available

at http://www.epa.gov/otaq/documents/tier3/ 420f14010.pdf

.

51 See RTC and references therein. 52 http://www.epa.gov/environmentaljustice/.

53 See page 25 of the TSD to the February 5, 2013 Proposed Rule. 54 See, 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.

55 See, for example, document number 0150, 0152, 0166, 0173, 0302, and 0303 in the docket for
this rule.

56 See document number 0122 in docket for this
rule.

57 See document numbers 0182, 0183, and 0184
in the docket for this rule.

58 EPA 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 NO X . In 2014,
EPA finalized new vehicle emission
standards and reduced the fuel sulfur content of gasoline to achieve additional reductions in tailpipe and evaporativeemissions 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 directedEPA 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 allowadditional 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


### 46523 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

59 See document 0219 in the docket for this rule.

60 See discussions under Executive Order 12898 in 78 FR 8793 (February 5, 2013) and 78 FR 62520 (October 22, 2013). 61 The OAQPS Control Cost Manual is now
referred to as the EPA Control Cost Manual. 62 See Table 12 of the TSD to the February 5, 2013 Proposed Rulemaking, available as document
number 0014 in the docket for this rule.

63 See MS Excel document titled ‘‘EPA cost analysis for NGS’’ within document number 0004
in the docket for this rule.

64 See Table 3 of our Proposed Rule, 78 FR 8281 (February 5, 2013).

65 See 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 NO X than would have been achieved under BART,
but also reductions of several other pollutants, including SO 2 , PM, CO 2 , 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 asaverage and incremental costeffectiveness values based on EPA and SRP assumptions for total annual cost
and total annual NO X reductions. Basedon 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


### 46524 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

66 See, 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). 67 See RTC and references therein.

68 78 FR 8281, February 5, 2013. per ton of NO X 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 NO X 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—C OST 

### E STIMATES FOR 

### SCR IN 

### 2010 AND 

### 2013 D OLLARS

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 theaverage and incremental costeffectiveness of controls, in both 2010 and 2013 dollars, based on EPA and SRP assumptions for total annual cost

and annual NO X reductions achieved by

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



### TABLE 

### 3—C OST 

### E FFECTIVENESS OF 

### C ONTROLS IN 

### 2010 AND 

### 2013 D OLLARS

2010 $ 2013 $

EPA SRP EPA SRP

SCR+ LNB/SOFA: Total Annual Cost * ................................................. $67.5 million ........... $80.2 million ........... $74.4 millio n $92.6 million.

Annual NO X reduced (tpy) ...................................... 28,573 .................... 26,180 .................... 28,573 26,180.
NO X 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


### 46525 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

69 For 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 NO X 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 controltechnology 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 ofpresumptive 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, andto 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


### 46526 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

71 See RTC and references therein. 72 See BART Guidelines at 70 FR 39169 (July 6, 2005). 73 See Proposed Rule at 78 FR 8282 (February 5, 2013) and TSD at pages 71–72.

74 See Proposed Rule at 78 FR 8283 (February 5, 2013).

75 See EPA, 2010, ‘‘Summary of Expert Opinions
on the Existence of a Threshold in the Concentration-Response Function for PM 2.5 -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 SO 2 and they also have to make significant capital investments to comply with other regulatory programs
and initiatives such as the revised SO 2 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 fortheir 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 NO X 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 NO X from NGS. EPA has
not conducted a health risk evaluation for this rulemaking that attempts to characterize or quantify a public health
benefit. Because NO X 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


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

Mortality Technical Support Document.’’ Available
from http://www.epa.gov/ttn/ecas/regdata/Benefits/ thresholdstsd.pdf.

76 See Proposed Rule at 78 FR 8280, 8284 and 8285 (February 5, 2013).

77 Id. at 8284. 78 See, 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 NO X emissions to levels below the presumptive NO X 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

NO X 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

NO X 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 SO 2 to SO 3 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

NO X , 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


### 46528 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

80 See RTC and references therein.

81 See 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.

82 See RTC and references therein. 83 SRP 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).

84 See RTC and references therein.

85 Id.

86 See RTC and references therein. 87 See RTC and references therein.

88 See 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 SO 2 and NO X 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


### 46529 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

89 W.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.

90 EPA 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). 91 EPA’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).

92 See RTC and references therein. 93 The 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 NO X 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 NO X 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 analysisdescribed 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

NO X 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 NO X 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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94 See RTC and references therein. 95 See RTC and references therein. 96 See, 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 Units1 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 apreliminary 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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98 See 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.

99 See 77 FR 14604, 14608–14610 (March 12, 2012) for a detailed discussion of the presumptive
limits. 100 See May 2012 Brattle Group document, page 12 and page 17, in the docket for this rule.

101 See EPA 2002 Multipollutant Strategies document, page 22, in the docket for this rule.

102 See page 17 of the EarthJustice comment letter,
in the docket for this rule. 103 See 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).

104 See 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 accommodateperiods of startup, shutdown, and loadcycling operation.

Comment: Presumptive Limit for NO X
. Several commenters noted that with existing LNB/SOFA controls, NGS emits

NO X 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 NO X 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 ofthe 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

NO X 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). 106 EPA initially codified the requirements for

NGS to meet an SO 2 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 SO 2 FIP to 40 CFR 49.5513

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

109 See 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 thestrategy 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 SO 2 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 SO 2 Comment: Support for finding that Reasonable Progress is met for SO 2. Several commenters noted that EPA recognized in the Proposed Rule that the
emission limits EPA established for SO 2 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 SO 2 emissions. One commenter noted that the existing SO 2 limit at NGS is more stringent than the BART Guidelines’ presumptive SO 2 limit.

Response: EPA agrees with these
comments. As EPA stated in our proposal in February 2013, the SO 2 emissions limit established in EPA’s

1991 SO 2 FIP was determined to be better than BART under the visibility regulations addressing reasonably attributable visibility impairment. Specifically, EPA determined that promulgating a SO 2 emission limit of 0.10 lb/MMBtu on an annual average basis would result in greater cumulative

SO 2 emissions reductions and visibility improvement over time than would the

SO 2 BART limit that EPA had proposed for NGS. NGS installed a wet flue gas desulfurization system to reduce SO 2 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.

112 Although 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 SO 2 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 NO X Caps will require
NGS to achieve emission reductions similar to those required under Alternative A1 because the 2009–

2029 NO X Cap is based on emissions that would be expected to occur under Alternative A1 (closure of one unit in 2019) and the 2009–2044 NO X 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 SO 2 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 NO X 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 NO X 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, NO X 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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115 See 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.’’

116 See page 22 of the EarthJustice comment letter dated January 3, 2014 (document 0367 in the docket for this rule).

117 See document number 0372 in the docket for
this rule.

118 Id. page 21. 119 See Proposed Rule at 78 FR 8289 (February 5, 2013).

120 See RTC and references therein. In 2011, NGS emitted 19,900 tons of NO X , in 2012, NGS emitted nearly 16,500 tons of NO X and in 2013, nearly 17,500 tons of NO X
. 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 NO X 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 NO X 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 NO X cap to prevent alternatives from being compared to an artificially inflated
estimate of total NO X 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 NO X 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, NO X 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 NO X 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 NO X 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 theRegional 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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121 See 78 FR 8284 (February 5, 2013).

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

124 See 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 NO X 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 thebaseline 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 thefacility), 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 NO X 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 NO X 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 NO X 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 NO X cap, would result in a significantly higher BART Benchmark.

The commenter also argues that in calculating the NO X 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


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

125 See Table 3 of our Supplemental Proposal at 78 FR 62516 (October 22, 2013).

126 See 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. 127 See tab titled ‘‘Outage Cycle’’ in the document titled ‘‘EPA Analysis of BART Alternatives’’ in
document number 0004 in the docket for this rule. 128 See document titled ‘‘EPA Analysis of BART
Alternative.xlsx’’ in document 0004 in the docket
for the rule.

129 See 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

NO X 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 NO X Cap. The commenter represents EPA’s NO X Cap as the
scenario it calls ‘‘CAP–1’’ with a value of 494,899 tons. This value is consistent
with the 2009–2044 NO X 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 NO X 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

NO X 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 NO X 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 NO X Cap separately, the commenter combines all of the assertions together to argue that
the 2009–2044 NO X Cap should be 373,029 tons (121,870 tons, or 25 percent, lower than EPA’s proposed

2009–2044 NO X 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 NO X 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 NO X 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 NO X 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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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 NO X 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 NO X 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 NO X emissions in 2018 would equal 10,611 tons per year.

NO X 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

NO X , but also emissions of SO 2 . 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 NO X 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 NO X 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


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

130 See 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 NO X 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 NO X 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 NO X emissions over 2009–2044 remain below the 2009–2044 NO X 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

NO X 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 capacityis in compliance with all preconstruction permitting requirements, as applicable, and (3) by December 31, 2030, the owner/operator shall comply
with a NO X 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

NO X 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 NO X Cap, the owner/operator shall ensure compliance
with the 2009–2029 NO X Cap. The

2009–2044 NO X Cap is defined in § 49.5513(j)(2)(ii) as no more than 494,899 tons of NO X , and the 2009–2029 NO X Cap is defined in § 49.5513(j)(2)(i) as no more than 416,865 tons of NO X
. The 2009–2029 NO X Cap is based on closure of one unit by December 31,
2019 and the 2009–2044 NO X 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 ReductionPlans that contain the anticipated yearby-year emissions to ensure compliance
with the 2009–2029 and 2009–2044

NO X 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 NO X Cap (as well as the 2009–

2029 NO X 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

NO X 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 NO X emissions over 2009–2044 for TWG Alternatives A1, A2, and A3 to provide assurance that the owner/operator could reasonably meet the 2009–2044 NO X Cap under the specific terms of those
alternatives. EPA does not need to


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131 The combination of the 2009–2044 and 2009–

2029 NO X Caps under TWG Alternative B means
that if NGS exceeds the 2009–2029 NO X 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 NO X Cap.

132 See EarthJustice letter, page 10, footnote 25.

133 See Supplemental Proposal, 78 FR 62513, footnote 21 (October 22, 2013). 134 40 CFR 51.308(d).

135 See 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 NO X 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 NO X 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 NO X 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 disagreesthat 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 NO X 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 NO X 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 NO X 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

NO X 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

NO X from NGS exceed the 2009–2044

NO X Cap prior to 2044, the operator of NGS must permanently cease operation of NGS. In addition, under Alternative B, if cumulative emissions of NO X exceed the 2009–2029 NO X 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 NO X 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 NO X 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 NO X . 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 NO X emissions
than the 2009–2044 NO X Cap.

Response: EPA disagrees with the
comment that the 2044 end date for the

NO X 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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136 See Section VII.F of the TWG Agreement (page 14). 137 Miller/Sahu Report, Table 2 at p. 7. 138 See Exhibit 2 to the Miller/Sahu report and
RTC and references therein.

139 See 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 NO X Cap and BART Benchmark,
and concluded that cumulative emissions from possible scenarios under
the TWG Alternative are not lower than

its NO X 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., NO X 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 NO X 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 NO X 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 NO X 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 NO X 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 NO X 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 NO X Cap, their analysis also shows
that when the TWG Alternative is compared to the BART Benchmark and

NO X Cap as proposed by EPA, the TWG Alternative scenarios it explored that
meet the 2009–2044 and 2009–2029

NO X 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 NO X Cap, but must verify that NGS can reasonably be expected to comply with

2009–2044 NO X Cap under the various constraints imposed under the TWG Alternatives (i.e., closure, curtailment, and a secondary 2009–2029 NO X 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 NO X 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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141 EPA 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 NO X 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, wehave 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 NO X , whereas the TWG Alternative, in 2019, would also reduce emissions of

SO 2 , PM, CO 2 , 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 NO X 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 NO X 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 NO X 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

NO X 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 NO X Cap, but the addition of this provision would prohibit emissions of NO X , 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 CO 2 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

NO X 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

NO X 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 NO X 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 NO X 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 NO X 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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142 At 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. 143 See document number 0122 in the docket for
this rule.

144 See document number 0182 and 0186 in the
docket for this rule. 145 At 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 NO X 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 NO X 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 NO X cap that would apply under
limits of 0.06 and 0.07 lb/MMBtu would exceed the proposed 2009–2044 NO X 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 NO X 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 NO X cap based on a BART
limit of 0.06 or 0.07 lb/MMBtu would be very similar to the proposed 2009–2044

NO X 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 NO X 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 NO X emissions to a level that is at least 33,000 tons
below the NO X 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 NO X 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 NO X 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 NO X 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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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 NO X 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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146 http://www.gpo.gov/fdsys/pkg/WCPD-2000-11- 13/pdf/WCPD-2000-11-13-Pg2806-2.pdf

. 147 See 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.

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

149 See 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.

151 See page 25 and 26 of the TSD to the Proposed Rule, document 0014 in the docket for this rule. 152 See document titled ‘‘Updated Timeline of all
Tribal Consultation on NGS

_for Final Rule.pdf’’ in
the docket for the rule.

153 Id.

154 See comment numbers 0340, 0317, 0387, 0402, 0419, and 0421 in the docket for the rule.

155 See comment number 0440 in the docket for
the rule.

156 See 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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157 See 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.

158 The 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

.

159 See 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 NO X controls at NGS. Based on that analysis, EPA proposed a NO X 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

NO X 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 NO X reductions over time, as well as a cap in cumulative

NO X emissions from NGS over 2009– 2044 (2009–2044 NO X 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 NO X 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 NO X 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 NO X 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


### 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 NO X 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 NO X 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


### 46549 Federal Register / Vol. 79, No. 153 / Friday, August 8, 2014 / Rules and Regulations

160 See Joint Federal Agency Statement Regarding Navajo Generating Station, dated January 4, 2013, in the docket for this proposed rulemaking. 161 See Factor 2 analysis, 78 FR 8281–8284 (February 5, 2013).

162 Id.

163 Id. at 8291.

164 Id. at 8289. 165 As 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 federalshare of energy being generated from NGS with lowemitting energy; (3) commitments by Interior to reduce or offset emissions of carbon dioxide (CO 2 ) 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.

166 See document titled ‘‘Updated Timeline of All
Tribal Consultations on NGS for Final Rule.docx’’ in the docket for this rulemaking.

167 See 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 tocollaborate 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 NO X 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 NO Xemissions 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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169 See comment numbers 0340, 0317, 0387, 0402, 0419, and 0421 in the docket for the rule.

170 See comment number 0440 in the docket for
the rule.

171 See document titled ‘‘2014

_ 0107 EPA Letter to Chairman Honanie with Enclosure 1.pdf’’ in the
docket for this rule.

172 See 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. 173 EPA’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 NO X 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 NO X , 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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174 See, 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.

175 See, for example, document number 0150, 0152, 0166, 0173, 0302, and 0303 in the docket for
this rule.

176 See document number 0122 in the docket for this rulemaking.

177 See document numbers 0182, 0183, and 0184 in the docket for this rulemaking. 178 EPA 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.

179 See 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 NO X , but also reductions of several other pollutants, including SO 2 , PM, CO 2 , 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 NO X reductions than would have been achieved under BART, will result in step-wise reductions of NO X 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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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 NO X 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

NO X 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 NO X Cap means a limit on emissions from Units 1, 2, and 3 of no more than 416,865 tons of NO X.

(ii) 2009–2044 NO X Cap means a limit on emissions from Units 1, 2, and 3 of no more than 494,899 tons of NO X.

(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-NO X 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) NO X means nitrogen oxides expressed as nitrogen dioxide (NO 2 ).

(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

NO X. Total cumulative NO X emissions from Units 1, 2, and 3, from January 1, 2009 to December 31, 2044, may not
exceed the 2009–2044 NO X Cap. The owner/operator must implement the applicable operating scenario, under paragraph (j)(3)(i) of this section, to

ensure NO X emission reductions
sufficient to maintain total cumulative

NO X emissions from Units 1, 2, and 3
below the 2009–2044 NO X Cap.

(i) Operating scenarios to comply with

2009–2044 NO X 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 NO X 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

NO X from Units 1, 2, and 3, based on annual reports required under paragraph (j)(4)(ii) of this section,
exceed the 2009–2044 NO X 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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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 regulatoryrequirements, 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 NO X 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

NO X from Units 1, 2, and 3, based on annual reports required under paragraph (j)(4)(ii) of this section,
exceed the 2009–2044 NO X 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 NO X 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

NO X from Units 1, 2, and 3, based on annual reports required under paragraph (j)(4)(ii) of this section,
exceed the 2009–2044 NO X Cap at any time prior to December 31, 2044.

(D) Alternative B. ( 1 ) Total cumulative

NO X emissions from Units 1, 2, and 3 may not exceed the 2009–2044 NO X Cap
or the 2009–2029 NO X Cap.

( 2 ) The owner/operator must cease operation of Units 1, 2, and 3 if total
cumulative emissions of NO X from Units 1, 2, and 3, based on annual reports required under paragraph (j)(4)(ii) of this section, exceed the

2009–2029 NO X 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 NO X 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 NO X Cap.

( 3 ) The owner/operator must permanently cease operation of Units 1, 2, and 3 if total cumulative emissions of

NO X from Units 1, 2, and 3, based on annual reports required under paragraph (j)(4)(ii)), exceed the 2009–

2044 NO X 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 NO X 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 NO X from the previous full calendar year. In addition, the owner/operator must also report total cumulative emissions of

NO X from NGS to assure compliance
with the 2009–2044 NO X Cap and the

2009–2029 NO X 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 NO X 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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(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 NO X that do not exceed the 2009–2029 NO X 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 NO X 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 NO X emissions
remain below the 2009–2029 NO X 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 NO X that do not exceed the 2009–2044 NO X 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 NO X emissions
remain below the 2009–2044 NO X 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 NO X , 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 NO X 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

NO X pounds per hour measurement and the heat input measurement. The
calculation of NO X pounds per hour and heat input relative accuracy shall be evaluated each time the CEMS undergo relative accuracy testing.

(6) Compliance determination for NO X emission limits. (i) Compliance with the

NO X 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 NO X 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 NO X 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 NO X pounds per hour or heat input is not available for any hour for a Unit, that heat input and NO X 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 NO X and heat input for each hour. (ii) Each Boiler Operating Day rolling average emission rate for NO X calculated in accordance with paragraph (j)(6)(i) of this section.

(iii) Each unit’s 30 Boiler Operating Day pounds of NO X 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 NO X 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 NO X 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 NO X 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

NO X 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

NO X , 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,


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

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**