[Federal Register Volume 78, Number 204 (Tuesday, October 22, 2013)]
[Proposed Rules]
[Pages 62509-62523]
[FR Doc No: 2013-24281]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 49

[EPA-R09-OAR-2013-0009; FRL-9901-66-Region9]

Approval of Air Quality Implementation Plans; Navajo Nation;
Regional Haze Requirements for Navajo Generating Station; Supplemental
Proposal

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental proposed rule and notice of public hearings.

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SUMMARY: On February 5, 2013, EPA published its proposed source-
specific Federal Implementation Plan (FIP) requiring the Navajo
Generating Station (NGS), located on the Navajo Nation, to reduce
emissions of oxides of nitrogen (NOX) under the Best
Available Retrofit Technology (BART) provision of the Clean Air Act
(CAA or Act). EPA proposed the BART FIP to reduce visibility impairment
caused by NGS at 11 National Parks and Wilderness Areas. EPA's proposed
FIP included: (1) A proposed BART determination; (2) A proposed
``better than BART'' alternative that achieves greater reasonable
progress towards the national visibility goals than BART; and (3) a
framework for evaluating additional alternatives to BART. This
framework for evaluating additional alternatives was included in the
proposal due to the unique purpose and history of NGS and the numerous
stakeholder interests in it. On March 19, 2013 and June 19, 2013, EPA
provided two extensions of the public comment period based on requests
of several stakeholders who were actively working to develop an
alternative to BART. On July 26, 2013, a group of stakeholders, known
as the Technical Work Group (TWG), submitted to EPA their suggested
alternative to BART (the ``TWG Alternative''). The TWG Alternative
establishes a lifetime cap in NOX emissions over 2009-2044
(the 2009-2044 NOX Cap) that is equivalent to the cumulative
NOX emissions over 2009-2044 that NGS would emit under EPA's
proposed BART determination of 0.055 lb/MMBtu achieved within five
years of the final rule. Due to on-going lease and ownership
uncertainties, the operators of NGS cannot yet commit to a single
course of action for maintaining emissions below the 2009-2044
NOX Cap. The TWG Alternative therefore includes several
alternative operating scenarios for meeting the 2009-2044
NOX Cap. EPA did not participate in the TWG or assist in
developing the TWG Alternative, and has independently evaluated the TWG
Alternative to determine if it meets the requirements of the CAA and
the Regional Haze Rule (RHR). In this action, EPA is proposing to
determine that the TWG Alternative is ``better than BART'' because
maintaining emissions below the 2009-2044 NOX Cap, as
provided in the TWG Alternative, achieves greater reasonable progress
than EPA's proposed BART determination towards the national visibility
goal. EPA is accepting comment concurrently on today's Supplemental
Proposal and our proposal from February 5, 2013.

DATES: Comments on EPA's February 5, 2013 proposal and today's
Supplemental Proposal for NGS must be postmarked no later than January
6, 2014.

ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2013-0009, by one of the following methods:
    (1) Federal eRulemaking Portal: www.regulations.gov. Follow the on-
line instructions.
    (2) Email<EMAIL_ADDRESS>    (3) Mail or deliver: Anita Lee (Air-2), U.S. Environmental
Protection Agency Region 9, 75 Hawthorne Street, San Francisco, CA
94105-3901.
    For more detailed instructions concerning how to submit comments on
this supplemental proposed rule, and for more information on our
proposed rule, please see the notice of proposed rulemaking, published
in the Federal Register on February 5, 2013 (78 FR 8274).
    Instructions: All comments will be included in the public docket
without change and may be made available online at www.regulations.gov,
including any personal information provided, unless the comment
includes Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. Information that you
consider CBI or otherwise protected should be clearly identified as
such and should not be submitted through www.regulations.gov or email.
www.regulations.gov is an ``anonymous access'' system, and EPA will not
know your identity or contact information unless you provide it in the
body of your comment. If you send an email directly to EPA, your email
address will be automatically captured and included as part of the
public comment. If EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, EPA may not be
able to consider your comment.
    Hearings: EPA has scheduled five public hearings to accept oral and
written comments on the proposed rulemaking. Prior to, or concurrent
with, each public hearing, EPA will be holding an informal open house
to allow members of the public additional time to review information
related to EPA's proposed BART determination and Supplemental Proposal,
and to speak with representatives from EPA. Any comments made to EPA
staff during the open houses must still be provided in writing or
orally during the formal public hearing in order to be considered in
the record. The open house and public hearing schedule is as follows:
    1. LeChee Chapter House (Navajo Nation), located in LeChee,
Arizona, three miles south of Page on Coppermine Road (Navajo Route
20),<PHONE_NUMBER>, November 12, 2013, concurrent Open House and
Public Hearing from 10 a.m.-1 p.m., local time;
    2. Page High School Cultural Arts Building, 434 Lake Powell
Boulevard, located in Page, Arizona,<PHONE_NUMBER>, November 12, 2013,
Open House from 3-5 p.m., local time and Public Hearing from 6-9 p.m.,
local time;
    3. Hopi Day School, Quarter-Mile East Main Street, located in
Kykotsmovi, Arizona,<PHONE_NUMBER>, November 13, 2013, Open House from
3-5 p.m., local time and Public Hearing from 6-9 p.m., local time;
    4. Phoenix Convention Center, 100 North 3rd Street, located in
Phoenix, Arizona,<PHONE_NUMBER>, November 14, 2013, Open House from 3-
5 p.m., local time and Public Hearing from 6-10 p.m., local time;
    5. Proscenium Theatre, Pima Community College West Campus, Center
for the Arts Building located two miles west of Interstate-10 on St.
Mary's Road,<PHONE_NUMBER>, in Tucson, Arizona-November 15, 2013, Open
House from 3-5 p.m., local time and Public Hearing from 6-9 p.m., local
time.
    EPA will provide oral interpretation services between English and
Din[eacute] at the open houses and public hearings in LeChee and Page.
EPA may provide oral interpretation services between English and the
Hopi language at the open house and public hearing in Kykotsmovi,
pending availability of a Hopi interpreter. To request additional oral
interpretation services or to request reasonable accommodation for a
disability, please contact the person listed in the FOR FURTHER
INFORMATION CONTACT section, by October 21, 2013. Verbatim transcripts,
in English, of the hearings and written statements provided at the
hearings will be included in the docket for this rulemaking.

    Oral testimony may be limited to five minutes or less for each
commenter to address the proposal or supplemental proposed rule. We
will not be providing equipment for commenters to show overhead slides
or make computerized presentations. The public hearings for the four
evening events are scheduled to close at 9 p.m. (in Page, Kykotsmovi,
and Tucson) or 10 p.m. (in Phoenix), but may close later, if necessary,
depending on the number of speakers wishing to participate.
    Written statements and supporting information submitted
electronically or by mail during the comment period will be considered
with the same weight as any oral comments and supporting information
presented at the public hearings. If you are unable to attend the
hearings but wish to submit comments on the proposed rule, you may
submit comments as indicated in the ADDRESSES section above.
    Docket: The index to the docket for this action is available
electronically at 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 EPA Region 9 (e.g., maps, voluminous reports,
copyrighted material), and some may not be publicly available in either
location (e.g., 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.

FOR FURTHER INFORMATION CONTACT: Anita Lee, EPA Region 9, (415) 972-
3958<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document, ``we'', ``us'',
and ``our'' refer to EPA.

Table of Contents

I. Background
    A. The Significance of the Navajo Generating Station
    B. EPA's February 5, 2013 Proposed BART Determination
    C. Technical Work Group Agreement
II. Legal Background for Proposing the TWG Alternative to BART as
Achieving Greater Progress Towards the National Visibility Goal
III. EPA's Technical Evaluation of Greater Reasonable Progress
Towards the National Visibility Goal
    A. Summary of TWG Alternative to BART
    B. EPA's Technical Evaluation of TWG Alternative to BART
IV. EPA's Supplemental Proposal
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
13563B. Paperwork Reduction Act
    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

I. Background

A. The Significance of the Navajo Generating Station

    NGS is a coal-fired power plant located on the Navajo Nation Indian
Reservation, just east of Page, Arizona, approximately 135 miles north
of Flagstaff, Arizona. Emissions of NOX from NGS affect
visibility at 11 National Parks and Wilderness Areas that are
designated as Class I federal areas, mandated by Congress to receive
heightened protection: Arches National Park (NP), Bryce Canyon NP,
Canyonlands NP, Capitol Reef NP, Grand Canyon NP, Mazatzal Wilderness
Area (WA), Mesa Verde NP, Petrified Forest NP, Pine Mountain WA,
Sycamore Canyon WA, and Zion NP. These areas support an active tourism
industry drawing over four million visitors to the Grand Canyon
National Park alone in 2011.\1\ NGS is subject to the BART requirements
of the CAA and the RHR based on its age and its effects on visibility
in Class I areas. For a more detailed discussion of our determination
that NGS is subject to BART and the requirements of the RHR, please see
our proposed FIP at 78 FR 8274 and 8277 (February 5, 2013).
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    \1\ See document titled ``Grand Canyon Annual Visitation.pdf''
within document number 0005 in the docket for this proposed
rulemaking at EPA-R09-OAR-2013-0009.
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    NGS is co-owned by six entities: the U.S. Bureau of Reclamation
(Reclamation)--24.3 percent, Salt River Project Agricultural
Improvement and Power District (SRP), which also acts as the facility
operator--21.7 percent, Los Angeles Department of Water and Power
(LADWP)--21.2 percent, Arizona Public Service (APS)--14 percent, Nevada
Energy (NV Energy, also known as Nevada Power Company)--11.3 percent,
and Tucson Electric Power (TEP)--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 providing power to the
Central Arizona Project (CAP).\2\ The 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-tribal agricultural water users in central Arizona, Indian tribes
located in Arizona, and municipal water users in Maricopa, Pinal, and
Pima counties.\3\ 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.\4\ Electricity from NGS powers the
pumps that move CAP water to its destinations along the distribution
system.
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    \2\ See information on the Central Arizona Project at http://www.usbr.gov/projects/Project.jsp?proj_Name=Central+Arizona+Project. See also report by the National
Renewable Energy Lab (NREL), discussed in more detail in Section
G.iii of this notice, titled ``Navajo Generating Station and Air
Visibility Regulations: Alternatives and Impacts'', revision dated
March 2012 (NREL report) within document number 0005 in the docket
for this proposed rulemaking at EPA-R09-OAR-2013-0009.
    \3\ See Section titled ``Welcome'' on CAP homepage: http://www.cap-az.com/.
    \4\ See, for example, Section 4 of the NREL report and Comments
from the Central Arizona Water Conservation District on the NREL
report to DOI and EPA dated February 23, 201[2], within document
number 0005 in the docket for this proposed rulemaking at EPA-R09-
OAR-2013-0009.
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    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.\5\ 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 a fund to support the tribal
water settlement agreements.\6\ The U.S. Department of the Interior
(DOI or the Interior), through Reclamation, plays an important role in
the implementation of

these settlement agreements and the management of the funds set aside
for water infrastructure development for tribes.
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    \5\ See Table 7, 78 FR at 8283 (February 5, 2013).
    \6\ Id.
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    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 paid to the Navajo Nation and Hopi Tribe contribute to the annual
revenues for both governments.\7\
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    \7\ Id.
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    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.\8\ The Joint Statement
also recognizes the trust responsibilities of the Federal government to
Indian tribes.
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    \8\ 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.
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B. EPA's February 5, 2013 Proposed BART Determination

    As previously stated, NGS is subject to the BART requirements of
the CAA and the RHR based on its age and its effects on visibility in
Class I areas. Because NGS is located in Indian country, and because
the Navajo Nation has not developed a Tribal Implementation Plan to
implement the BART requirement for NGS, on February 5, 2013, EPA
proposed a BART determination to require NGS to meet a NOX
emission limit of 0.055 pound per million British thermal units of heat
input (lb/MMBtu) within five years of the effective date of a final
rule.\9\ 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 proposed an Alternative to BART (i.e., Alternative
1) within the ``better than BART'' framework we outlined. EPA
recognized that there may be other approaches that could result in
better visibility benefits over time and that there may be changes in
energy demand, supply, or other developments over the next several
decades that may change electricity generation on the Navajo Nation.
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    \9\ Unless otherwise noted, the averaging period, for all
emission limits, is based on a rolling average of 30 boiler
operating days.
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    EPA's proposed ``better than BART'' framework established total
emissions of NOX over 2009-2044 as the ``BART Benchmark''
against which an Alternative to BART would be compared.\10\ EPA's
``better than BART'' framework included a NOX emission
credit for the early and voluntary installation of LNB/SOFA over the
2009-2011 timeframe (LNB/SOFA credit).\11\ As discussed in our proposed
rulemaking, EPA was exercising its authority and discretion under
section 301(d)(4) of the CAA and 40 CFR 49.11(a) to propose an extended
timeframe for an alternative measure under the RHR for NGS. We proposed
the LNB/SOFA credit supporting an extended timeframe based on the
flexibility under section 301(d)(4) of the CAA, and 40 CFR
49.11(a).\12\ EPA applied the LNB/SOFA credit to each Alternative to
BART (adjusted emissions) and compared those values against the BART
benchmark. Total adjusted emissions of an Alternative to BART over
2009-2044 that were lower than the BART Benchmark were then determined
to be ``better than BART'' and result in greater reasonable progress
towards the national visibility goal than BART. Conversely,
alternatives that result in total NOX emissions exceeding
the BART Benchmark would not be acceptable unless those alternatives
provided additional emission reductions to bridge the deficit in
NOX emission reductions.
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    \10\ In our proposed rulemaking, we use the term ``BART
threshold'' to describe the total emissions of NOX over
2009-2044 against which Alternatives to BART would be compared.
Although we use the term ``BART benchmark'' here, the two terms are
intended to be identical in meaning.
    \11\ The NOX reductions achieved by installing the
modern LNB/SOFA were not required under any regulatory program under
the CAA and resulted in more NOX emission reductions
during the period between 2009 and the BART compliance date than if
LNB/SOFA were installed concurrently with SCR by the BART compliance
date.
    \12\ See 78 FR 8289 (February 5, 2013).
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    To calculate the value of the LNB/SOFA credit, EPA first calculated
the total NOX emissions over 2009-2044 that NGS would emit
if NGS had waited until the proposed BART compliance date to install
LNB/SOFA concurrently with SCR. EPA then calculated total
NOX emissions over 2009-2044 with the actual installation
date of LNB/SOFA in 2009-2011 and installation of SCR by the BART
compliance date. The difference between the two values was calculated
to be the LNB/SOFA credit.\13\ Under EPA's proposed framework, EPA
established, as the BART benchmark, the total NOX emissions
over 2009-2044 with the actual installation date of LNB/SOFA in 2009-
2011 and installation of SCR by the BART compliance date. For a more
detailed discussion of this approach, please see our proposed FIP at 78
FR at 8288-91.
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    \13\ As discussed in greater detail in our proposed rule (78 FR
at 8289, February 5, 2013), EPA notes that LNB with SOFA is a
potential control option evaluated under BART and that these
technologies are typically used in conjunction with SCR or other
add-on controls to first reduce NOX formation during
combustion. EPA recognizes that the owners of NGS could have waited
until the compliance date of the final BART determination before
installing any new controls, including LNB/SOFA, and that the early
and voluntary NOX reductions achieved beginning in 2009
were not required under any regulatory program under the CAA.
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    EPA applied this framework to several alternatives we developed. In
the February 2013 proposal, we proposed one Alternative to BART that
would provide an additional three to five years to NGS in the schedule
for the installation of new post-combustion control equipment to meet
the proposed BART limit of 0.055 lb/MMBtu (i.e., Alternative 1
requiring compliance with the proposed BART limit on one unit per year
in 2021, 2022, and 2023). Additional NOX emissions resulting
from delayed compliance were offset by the emissions credit NGS
achieved by its early and voluntary installation of LNB/SOFA. We
calculated that under this proposed Alternative 1, total adjusted
emissions of NOX over 2009-2044 were lower than total
emissions of NOX under EPA's proposed BART determination.
Therefore, EPA proposed to find that Alternative 1 achieves greater
reasonable progress than BART.
    In the February 2013 proposal, EPA also described, but did not
propose, two additional alternatives (Alternatives 2 and 3) that would
provide an additional five to eight years for NGS to meet the proposed
BART limit of 0.055 lb/MMBtu (i.e., Alternatives 2 and 3 called for
compliance with the BART limit on one unit per year over 2023-2025 and
2024-2026, respectively). Total NOX emissions over 2009-
2044, after accounting for the LNB/SOFA early installation credit, from
each of these two additional alternatives both exceeded the BART
Benchmark. However, under our proposed framework, these two additional
alternatives would be viable if the owners of NGS achieved sufficient
additional emission reductions to bridge the NOX reduction
deficit. EPA requested comment on our proposed ``better than BART''
framework and how NGS might achieve the emission reduction bridge
necessary for the longer compliance schedules under

Alternatives 2 and 3 to qualify as ``better than BART.''
    In both the February 2013 proposal and in the accompanying fact
sheet, EPA encouraged a robust public discussion of our proposed BART
determination, our proposed Alternative 1, as well as our proposed
``better than BART'' framework and other possible alternatives that
meet the framework. In addition, we recognized the potential need for a
supplemental proposal if other approaches developed by other parties
are identified as meeting the requirements of the CAA.\14\
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    \14\ See Fact Sheet at http://www.epa.gov/region9/air/navajo/index.html#proposed.
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    After EPA published the proposed FIP on February 5, 2013, we
received requests for a 90-day extension of the public comment period
from the Navajo Nation, the Gila River Indian Community, SRP, and the
Central Arizona Water Conservation District (CAWCD), the CAP operating
entity, in order to allow stakeholders additional time to develop
alternatives to BART for EPA's consideration. Recognizing the
significant time and effort necessary to develop viable alternatives
and the critical importance of active participation by affected parties
in the development of alternatives to BART, on March 19, 2013, EPA
extended the close of the public comment period to August 5, 2013 (78
FR 16825).
    On June 10, 2013, EPA signed a notice, published on June 19, 2013,
of our intent to hold five public hearings throughout the state of
Arizona (78 FR 36716), at one location each on reservation lands of the
Navajo Nation and Hopi Tribe, and in Page, Phoenix, and Tucson,
Arizona.
    On June 20, 2013, SRP submitted a letter, on behalf of itself and
certain other stakeholders, requesting another extension of the comment
period for NGS. The SRP letter described work that had been on-going
for several months with representatives from several organizations (the
TWG) to develop an Alternative to BART. On July 9, 2013, EPA extended
the close of the public comment period again to October 4, 2013 (78 FR
41012). On September 16, 2013, EPA signed a notice extending the close
of the public comment period a third time, to January 6, 2014.\15\
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    \15\ See document number 0172 in the docket for this proposed
rulemaking at EPA-R09-OAR-2013-0009.
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C. Technical Work Group Agreement

    On July 26, 2013, a group of stakeholders known as the TWG and
composed of the Central Arizona Water Conservation District (CAWCD),
the Environmental Defense Fund (EDF), the Gila River Indian Community
(Gila River, or the Community), the Navajo Nation, SRP, on behalf of
itself and the other non-federal Participants, the Department of the
Interior, and Western Resource Advocates, submitted a document
memorializing a multi-party agreement (the TWG Agreement) to EPA for
consideration.\16\ EPA had attended a ``kick-off'' meeting for the TWG
on March 21, 2013, at which we described our February 5, 2013 proposal,
but EPA did not have any further participation in the TWG.\17\ As
described in Section III of the TWG Agreement, ``Summary of Agreement
Elements; Reasonable Progress Alternative to BART, Obligations of
Support, and Reservation Right'', the Agreement consists of seven
elements: (1) A description of a ``Reasonable Progress Alternative to
BART'' (the TWG Alternative); \18\ (2) a study of options by
Reclamation for replacing the federal share of energy being generated
from NGS with low-emitting energy; (3) commitments by Interior to
reduce or offset emissions of carbon dioxide (CO2) by three
percent per year and facilitate the development of clean energy
resources; (4) commitments by Interior to mitigate potential impacts
from EPA's final BART rule to Affected Tribes; (5) a commitment by
Interior to carry out the Phase 2 Study by the National Renewable
Energy Laboratory (NREL) for the purposes of studying options for the
future of NGS; (6) a commitment by SRP to make funds available for a
Local Benefit Fund for community improvement projects within 100 miles
of NGS or the Kayenta Mine; and (7) a summary of obligations of the
Parties to the Agreement and miscellaneous legal provisions.
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    \16\ See ``Technical Work Group Agreement Related to Navajo
Generating Station (NGS)'' dated July 25, 2013, and submitted to EPA
on July 26, 2013, in the docket for this proposed rulemaking at EPA-
R09-OAR-2013-0009-0122.
    \17\ See document number 0033 in the docket for the proposed
rulemaking at EPA-R09-OAR-2013-0009.
    \18\ The ``Reasonable Progress Alternative to BART'' is a term
from the TWG Agreement. EPA interprets this term to have the same
meaning as an Alternative to BART or a ``better than BART''
Alternative, however, we do not otherwise use this term in today's
Supplemental Proposal.
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    The TWG Agreement, in its entirety, is included in the docket for
this proposed rulemaking. Appendix B to the TWG Agreement is the only
component of the TWG Agreement that is applicable to today's action.
EPA is not requesting comment on the provisions of the TWG Agreement
unrelated to Appendix B, and will not be responding to comments on
aspects of the TWG Agreement that are not related to our authority
under section 169A of the CAA to require BART or an Alternative to
BART.

II. Legal Background for Proposing the TWG Alternative to BART as
Achieving Greater Progress Towards the National Visibility Goal

    In our proposed BART determination for NGS on February 5, 2013 (78
FR 8274), we provided a detailed discussion of the statutory and
regulatory framework for addressing visibility, addressing sources
located in Indian country under 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. Please see 77 FR
8275-8277 for our discussion on these topics. In the following
paragraphs, we describe the legal background and authority for
evaluating Alternatives to BART and for providing additional compliance
flexibility to NGS.
    Under the CAA, compliance with emission limits determined as BART
must be achieved ``as expeditiously as practicable but in no event
later than five years'' after the effective date of the final BART
determination (See CAA 169A(b)(2)(A) and (g)(4)). Therefore, the BART
compliance date for NGS would be no later than 2019 if the rule is
finalized in 2014. As discussed in greater detail in our proposed BART
determination, EPA recognizes that the circumstances related to NGS
create unusual and significant challenges for a five-year compliance
schedule.\19\ Based on those challenges and our discretion under the
TAR for implementing CAA requirements on tribal lands, we considered
other options that are consistent with the CAA and RHR, and that
provide for a more flexible, extended compliance schedule.
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    \19\ 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 five years without also having
certainty that the lease and contract re-negotiations would conclude
in a timely and favorable manner. EPA understands that the owners of
NGS face numerous uncertainties and the unusual requirement to
comply with NEPA for lease and other rights-of-way 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 or 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.
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    EPA's BART regulations allow an Alternative to BART provided the
alternative results in greater reasonable progress than would have been
achieved

through installation of BART. 40 CFR 51.308(e)(2). The regulations
provide that an Alternative 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. 40 CFR
51.308(e)(2)(iii). Thus, if states had submitted timely regional haze
SIPs in 2007 with BART compliance deadlines in 2012, the RHR provided
over five additional years for the implementation of Alternatives to
BART.
    In our February 5, 2013 proposal for NGS, EPA proposed an
Alternative to BART (Alternative 1). In particular, EPA proposed 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. The 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 extended
timeframe for an alternative measure under the RHR for NGS. EPA
considered this extension of time to be consistent with the general
programmatic requirements. States and regulated sources accordingly had
almost 20 years under the RHR to design and implement alternative
measures to BART. Because of the myriad stakeholder interests and
complex governmental interests unique to NGS, we are only now
addressing the BART requirements for NGS. For all the reasons explained
above, we considered it appropriate to consider an extended compliance
period for NGS.
    Our proposal to require emission reductions beyond 2018 was
supported by the Tribal Authority Rule 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
application of this approach in a challenge to the FIP for the Four
Corners Power Plant, stating: ``[40 C.F.R. 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.'' Ariz. Public Serv. Co. v. EPA, 562 F.3d 1116 (10th Cir.
2009). 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.'' Id. While the decision in Arizona
Public Service Company 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. EPA's Technical Evaluation of Greater Reasonable Progress Towards
the National Visibility Goal

A. Summary of TWG Alternative to BART

    Appendix B of the TWG Agreement contains the TWG Alternative that
was submitted to EPA for consideration as a ''better than BART''
Alternative.\20\ The TWG Alternative was developed by the Technical
Work Group, which did not include EPA, to satisfy the ``better than
BART'' requirements of the RHR.\21\ The core element of the TWG
Alternative is that the TWG Alternative establishes a cap in
NOX emissions over the period 2009-2044 (the 2009-2044
NOX Cap). The TWG Alternative then outlines 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. The owners of NGS commit to maintaining emissions from NGS below
the 2009-2044 NOX Cap regardless of the post-2019 ownership
of NGS and the applicable operating scenario. In general, the operating
scenarios include specific actions for achieving emission reductions by
2019 and 2030 to ensure compliance with the 2009-2044 NOX
Cap. The TWG Alternative also provides for an operating scenario that
is less well-defined but establishes a second NOX emissions
cap over the period of 2009-2029 (the 2009-2029 NOX Cap)
that is equivalent to emission reductions that would be achieved by the
more well-defined operating scenarios. The 2009-2029 NOX Cap
would apply in addition to the 2009-2044 NOX Cap. The TWG
Alternative also includes annual reporting requirements to EPA.
---------------------------------------------------------------------------

    \20\ The TWG Alternative is divided into distinct operating
scenarios that the TWG calls Alternative A and Alternative B. The
TWG Alternative further divides Alternative A into sub-scenarios.
EPA refers to the sub-scenarios under Alternative A as A1, A2, and
A3. EPA is reviewing all four scenarios (Alternatives A1, A2, A3,
and B) together as one Alternative.
    \21\ The TWG Agreement also states that the TWG Alternative is
intended to satisfy any requirements of the Reasonably Attributable
Visibility Impairment (RAVI) program. On May 5, 2009, the National
Parks Conservation Association (NPCA) petitioned the Department of
the Interior to certify that emissions of NOX and
particulate matter cause visibility impairment at the Grand Canyon
National Park. This type of visibility impairment, reasonably
attributable from a single stationary source, is known as Reasonably
Attributable Visibility Impairment (RAVI). On January 20, 2011, NPCA
filed a complaint in the United States District Court for the
District of Columbia contending that the Department of the Interior
was unreasonably delaying making a finding of reasonable attribution
from NGS. In a letter dated March 8, 2011 to NPCA, the National Park
Service (NPS) declined to make such a finding based on EPA's on-
going work related to a BART determination for NGS. On June 30,
2011, the Court dismissed the complaint holding the NPS letter
refusing to make the finding of reasonable attribution constituted
denying the Petitioner's request for a RAVI finding. If NPS were to
certify RAVI at Grand Canyon from NGS, EPA must determine whether
visibility impairment at Grand Canyon is indeed reasonably
attributable to NGS. If EPA were to make a positive attribution
determination, then EPA would be required to conduct a BART
determination for NGS. We note, however, that while the process for
determining whether a given stationary source causes or contributes
to RAVI or regional haze are different, the process for determining
BART under both programs is essentially the same. In other words, a
BART determination for RAVI would likely be the same as a BART
determination for regional haze. The 2009 NPCA petition, the 2011
NPCA complaint, the 2011 letter from NPS, and the 2011 Court
decision are all included in the docket for this proposed
rulemaking.
---------------------------------------------------------------------------

    The 2009-2044 NOX Cap is calculated based on expected
emissions that would result if NGS complied with EPA's proposed BART
emission limit of 0.055 lb/MMBtu on each unit within five years of the
effective date of a final rule. The TWG Alternative also incorporates
EPA's proposed credit to NGS for the emission reductions achieved from
the early and voluntary installation of LNB/SOFA beginning in 2009 (the
LNB/SOFA credit).
    The TWG Alternative puts forth two main operating scenarios, with
additional sub-options, for limiting NOX emissions below the
2009-2044 NOX Cap. These scenarios are called TWG

Alternatives A and B. The TWG Alternative provides different operating
scenarios because of current uncertainty over the ownership interests
in NGS following the expiration of the initial NGS lease term at the
end of 2019. Specifically, two owners, LADWP and NV Energy, have
announced plans to divest from any continuing ownership interest in NGS
after 2019. These owners may retire or sell their interest in NGS. In
addition, the recent Lease Amendment with the Navajo Nation that
extends the NGS lease to 2044 includes an option for the Navajo Nation
to purchase up to a 170 MW ownership share in NGS.\22\
---------------------------------------------------------------------------

    \22\ See Section XI of the ``Amendment No. 1 to Indenture of
Lease Navajo Units 1, 2, and 3 Between the Navajo Nation and Arizona
Public Service Company, Department of Water and Power of the City of
Los Angeles, Nevada Power Company dba NV Energy, Salt River Project
Agricultural Improvement and Power District, and Tucson Electric
Company'', within document number 0150 in the docket for this
proposed rulemaking at EPA-R09-OAR-2013-0009.
---------------------------------------------------------------------------

    Each of the three scenarios under TWG Alternative A (i.e., A1, A2,
or A3) requires two significant emission reductions, one to occur by
December 31, 2019 and the other by December 31, 2030. The emission
reductions in the first step, by December 31, 2019, under TWG
Alternative A1 would be achieved through closure of one unit.
Alternative A2 would entail closure of one unit with an increase in
capacity, not to exceed 189 MW, at the remaining two units; Alternative
A3 would entail the curtailment of energy production across all three
units such that the emission reductions are equivalent to the closure
of approximately one unit. The emission reductions to occur in the
second step, under Alternatives A1-3, would occur by December 31, 2030,
and would be achieved by compliance of two units at NGS with an
emission limit of 0.07 lb/MMBtu, achievable with the installation of
SCR. Under the TWG Alternative, although the 2009-2044 NOX
Cap is calculated based on EPA's proposed BART emission limit of 0.055
lb/MMBtu, the owners of NGS commit to meeting a limit of 0.07 lb/MMBtu
from the installation of SCR. The operator states that a limit of 0.055
lb/MMBtu is not achievable for a retrofit application when startup,
shutdown, and load following emissions are included.\23\
---------------------------------------------------------------------------

    \23\ See Appendix B.1.A.3 of the Technical Work Group Agreement
on NGS, document number 0122 in the docket for this proposed
rulemaking. EPA does not consider the limit of 0.07 lb/MMBtu to be a
BART emission limit, rather, a component of the TWG Alternative.
Under the TWG Alternative, this higher emission rate is offset by
the closure of one unit, or the curtailment of generation. In other
words, despite the higher emission rate under the TWG Alternative
compared to EPA's proposed BART emission limit, NGS would comply
with the 2009-2044 NOX Cap because additional emission
reductions are achieved from closure or curtailment.
---------------------------------------------------------------------------

    Alternative A1 would be triggered if LADWP and NV Energy retire
their ownership shares of NGS without selling, or if LADWP and NV
Energy sell their ownership shares to an existing NGS participant and
the Navajo Nation does not elect to purchase an interest in NGS.
Alternative A2 is triggered if LADWP or NV Energy sell their ownership
shares to an existing NGS participant, the Navajo Nation elects to
purchase an interest in NGS, and the NGS participants can increase the
capacity of NGS by no more than 189 MW \24\ without triggering major
source pre-construction permitting requirements.\25\ Alternative A3 is
triggered if LADWP or NV Energy sell their ownership shares to an
existing NGS Participant, the Navajo Nation elects to purchase an
interest in NGS, and the NGS Participants cannot increase the capacity
of NGS without triggering major source pre-construction permitting
requirements.
---------------------------------------------------------------------------

    \24\ LADWP owns approximately 477 MW of NGS, while NV Energy
owns approximately 254 MW. The sum of their shares is 731 MW, which
is 19 MW short of one 750 MW unit at NGS. The Navajo Nation has the
option to purchase up to a 170 MW interest in NGS. A 189 MW limit in
the capacity increase is based on making up the 19 MW shortfall and
the maximum amount the Navajo Nation can purchase (i.e., the sum of
19 MW and 170 MW).
    \25\ The Prevention of Significant Deterioration (PSD) Program
generally requires pre-construction permitting for major sources if
the intended modification increases emissions of certain air
pollutants above the PSD significance thresholds. The TWG
Alternative also cites the Nonattainment New Source Review Program,
a pre-construction permitting program for areas that are not in
attainment with the National Ambient Air Quality Standards (NAAQS).
Currently, this program does not apply to NGS as it is not located
in an area that is out of attainment with any of the NAAQS.
---------------------------------------------------------------------------

    TWG Alternative B would be triggered if LADWP and/or NV Energy sell
their ownership interest to a third party (i.e., a party that is not an
existing NGS participant). TWG Alternative B establishes similar
emission reductions to Alternative A by setting a second NOX
emission cap over the 2009-2029 period, i.e., the 2009-2029
NOX Cap (calculated to be equivalent to the closure of one
unit in 2020), in addition to the 2009-2044 NOX Cap.
Alternative B specifies that NOX emissions must be
maintained below the cap during each applicable period (2009-2029 and
2009-2044), but does not specify how the NGS owners must operate NGS to
meet each cap. The TWG Alternative outlines annual emissions reporting
and planning requirements both to the public and to EPA to ensure
progress towards emissions goals and maintenance of emissions below the
2009-2044 NOX Cap.

B. EPA's Technical Evaluation of TWG Alternative to BART

    EPA is proposing to include the TWG Alternative as a second
``better than BART'' Alternative to achieve compliance with the
RHR.\26\ We are proposing to determine that the TWG Alternative
satisfies the requirements of the RHR as discussed below.
---------------------------------------------------------------------------

    \26\ In our proposed action on February 5, 2013, EPA proposed a
BART determination for NGS and Alternative 1 as a ``better than
BART'' Alternative. In today's action, we are proposing that the TWG
Alternative also meets our ``better than BART'' framework. Taken
together, EPA has proposed a BART determination for NGS, Alternative
1, and the TWG Alternative.
---------------------------------------------------------------------------

    As stated previously, the TWG Alternative establishes a 2009-2044
NOX Cap based on expected emissions that would result if NGS
complied with EPA's proposed BART determination. The TWG Alternative
also incorporates EPA's proposed LNB/SOFA credit into the 2009-2044
NOX Cap. In our February 5, 2013 proposed rule, EPA
established our proposed BART determination as a BART Benchmark based
on actual emissions and applied the LNB/SOFA credit to each Alternative
to BART (to calculate ``adjusted'' emissions). Adjusted emissions, from
each Alternative, were then compared against the BART Benchmark. As
discussed in the following paragraphs, these two methods of applying
credit for the early and voluntary installation of LNB/SOFA beginning
in 2009 are equivalent.\27\
---------------------------------------------------------------------------

    \27\ See also Spreadsheet titled ``Supplemental Better than BART
Alternatives.xlsx'' in the docket for this proposed rulemaking.
---------------------------------------------------------------------------

    As shown in our proposed rulemaking, EPA's proposed BART Benchmark
was 358,974 tons of NOX over 2009-2044.\28\ This value was
calculated assuming compliance with EPA's proposed BART emission limit
of 0.055 lb/MMBtu on January 1, 2018, based on a final rule effective
date of January 1, 2013. A final rule effective date of January 1, 2013
is no longer appropriate for NGS because EPA will

not issue a final BART rule by that date. The TWG Alternative provided
an example calculation for the 2009-2044 NOX Cap assuming a
final rule effective date of December 31, 2013, an emission limit of
0.055 lb/MMBtu, and the application of the LNB/SOFA credit to the
cap.\29\ The LNB/SOFA credit, as applied to the cap, assumes that LNB/
SOFA are installed at NGS concurrently with SCR, rather than using the
actual early installation dates on one unit per year over 2009-2011.
The example in the TWG Alternative calculates a 2009-2044
NOX Cap of 480,490 tons and acknowledges that the cap would
change depending on the actual effective date of the final rule. The
difference between the BART Benchmark from EPA's proposed rulemaking
(of 358,974 tons) and the example calculated in the TWG Alternative (of
480,490 tons) is based on the application of the LNB/SOFA credit to the
2009-2044 NOX Cap and the use of a different final rule
effective date, i.e., 2014 instead of 2013. Additionally, in our
proposed rulemaking, EPA included a transcription error in our
calculation of the BART Benchmark, which contributes nominally to the
difference.\30\
---------------------------------------------------------------------------

    \28\ See Table 12 at 78 FR at 8290 and document titled ``BART
Alternatives.xlsx'' in document number 0005 in the docket for this
proposed rulemaking at EPA-R09-OAR-2013-0009. In our BART proposal,
and in calculating the 2009-2044 NOX Cap in this
Supplemental Proposal, EPA used the average annual NOX
emissions from NGS over 2001-2008 (34,152 tons) to estimate future
annual emissions before compliance with the 0.055 lb/MMBtu
NOX limit. The TWG Alternative also used this value in
estimating its cap. Estimates for annual emissions in 2020 and
thereafter were based on the 0.055 lb/MMBtu NOX limit for
BART and the average heat input over 2001-2008. This method was
similarly used by EPA in our BART proposal and this Supplemental
Proposal, as well as the TWG Alternative.
    \29\ Regarding the final rule effective date, see Infra. at
footnote 33.
    \30\ EPA erroneously used the value 5,343 tons per year to
represent NOX emissions from NGS after installation of
SCR. The correct value was 5,345 tons per year. See, for example,
comparison of cells B23 and C23 in ``emissions'' tab of the
spreadsheet entitled ``BART Alternatives.xlsx'' in document number
0005 in the docket for this proposed rulemaking at EPA-R09-OAR-2013-
0009.

       Table 1--Differences Between BART Benchmark and Example Calculation of NOX Cap From TWG Alternative
----------------------------------------------------------------------------------------------------------------
                                                 BART Benchmark
                                                    for NOX                         Assumptions
----------------------------------------------------------------------------------------------------------------
As reported in 2/5/13 Proposed Rulemaking....            358,974  BART compliance by January 1, 2018 (final rule
                                                                   effective January 1, 2013).
Step 1: Correction for Transcription Error...            359,028  Transcription Error of 2 tpy for 27 years =
                                                                   addition of 54 tons.
Step 2: Plus Correction for Revised BART                 377,015  Change BART Compliance date from January 1,
 Compliance Date.                                                  2018 to January 1, 2019 = Difference between
                                                                   LNB/SOFA and SCR+LNB/SOFA for one year =
                                                                   23,325 tons minus 5,345 tons = 17,980 tons.
Step 3: Plus Application of LNB/SOFA Credit..            480,489  Early emission reductions over 2009-2018
                                                                   achieved from LNB/SOFA installation = (34,152
                                                                   tpy * 10 years)--(30,500 + 24,427 + 19,837 +
                                                                   (23,325 * 7 years) = 103,481 tons.
----------------------------------------------------------------------------------------------------------------

    Table 1 shows that the correction for EPA's transcription error, a
revised BART compliance date, and the application of the LNB/SOFA
credit to the BART Benchmark instead of alternatives, account for the
full difference between EPA's BART Benchmark, as reported in our
proposed rulemaking, and the example calculation from the TWG
Alternative.\31\
---------------------------------------------------------------------------

    \31\ Id.
---------------------------------------------------------------------------

    Using the value from Table 1 of 480,489 tons, representing total
NOX emissions over 2009-2044 if LNB/SOFA were installed
concurrently with SCR by 2019, and the value of 377,015 tons,
representing total NOX emissions over 2009-2044 with actual
installation years for LNB/SOFA, the LNB/SOFA credit is 103,481 tons.
As discussed previously, in our proposed rulemaking, EPA set, as the
BART Benchmark, the value of total NOX emissions over 2009-
2044 based on the actual early installation years for LNB/SOFA (i.e.,
377,015 tons), and applied the LNB/SOFA credit to BART Alternatives to
calculated a value for ``adjusted emissions''. If the ``adjusted
emissions'' were lower than the BART Benchmark, the BART Alternative
was determined to be ``better than BART''. The TWG Alternative,
instead, applied the LNB/SOFA credit to the 2009-2044 NOX
Cap (i.e., resulting in 480,489 tons, very close to the value reported
by TWG of 480,490 tons), and calculated total emissions from
Alternatives based on the actual early installation years for LNB/SOFA.
If emissions from the BART Alternative are lower than the 2009-2044
NOX Cap, the Alternative is ``better than BART''. Using
Alternative 1 from our February 5, 2013 proposed rulemaking, i.e.,
compliance with the proposed BART emission limit in 2021, 2022, and
2023, as an example, Table 2 shows that these two methods of comparing
Alternatives against BART are equivalent.\32\
---------------------------------------------------------------------------

    \32\ See also Spreadsheet titled ``Supplemental Better than BART
Alternatives.xlsx'' in the docket for this proposed rulemaking.

   Table 2--EPA and TWG Methods of Comparing Alternatives Against BART
------------------------------------------------------------------------
                                       BART            Alternative 1
------------------------------------------------------------------------
                               EPA Method
------------------------------------------------------------------------
Compliance Years..............  By 2019..........  2021, 2022, 2023.
Total Emissions (tons)........  377,008 tons.....  430,948 tons.
LNB/SOFA Credit...............  n/a..............  103,481 tons.
Adjusted Emissions............  n/a..............  327,467 tons.
Better than BART?.............  n/a..............  Yes, by 49,541 tons
                                                    (377,008-327,467
                                                    tons).
------------------------------------------------------------------------
                               TWG Method
------------------------------------------------------------------------
Compliance Years..............  By 2019..........  2021, 2022, 2023.
Total Emissions (tons)........  377,008 tons.....  430,948 tons.
LNB/SOFA Credit...............  103,481 tons.....  n/a.
Adjusted Emissions............  480,489 tons.....  n/a.
Better than BART?.............  n/a..............  Yes, by 49,541 tons
                                                    (480,489-430,948
                                                    tons).
------------------------------------------------------------------------

    As discussed previously, EPA anticipates that the compliance date
for BART would be based on the effective date of the final rule, which
is typically 60 days following publication of the final rule in the
Federal Register. Therefore, in calculating the 2009-2044
NOX Cap, EPA assumes that an effective date of July 1, 2014
is reasonable and justified.\33\ Based on a July 1, 2014 effective
date, compliance with the BART emission limit must occur by July 1,
2019. Using this compliance date, as well as correcting for the
transcription error in our proposed rulemaking and applying the LNB/
SOFA credit to the BART Benchmark instead of BART Alternatives, EPA
calculates the 2009-2044 NOX Cap to be 494,899 tons.\34\
---------------------------------------------------------------------------

    \33\ The comment period for EPA's proposed BART determination
and Supplemental Proposal will close in January 2013. EPA
anticipates that a final rule that considers and responds to all
comments cannot be completed until Spring 2014. Because a final rule
is typically effective 60 days following publication in the Federal
Register, EPA anticipates the effective date of the final rule will
occur no earlier than mid-summer 2014.
    \34\ See also Spreadsheet titled ``Supplemental Better than BART
Alternatives.xlsx'' in the docket for this proposed rulemaking.
---------------------------------------------------------------------------

    In our proposed BART determination on February 5, 2013, we
established a framework for evaluating other Alternatives to BART,
centered on our proposed BART determination that calculated a BART
benchmark for total NOX emissions over 2009-2044. We
compared total emissions from our proposed alternative, Alternative 1
(adjusted for the emission reductions associated with the early
installation of LNB/SOFA) against the BART benchmark to determine that
Alternative 1 was ``better than BART''. The TWG Alternative to BART
uses EPA's BART benchmark to establish an emission cap and commits to
operate NGS in a manner such that total NOX emissions over
2009-2044 remain below the 2009-2044 NOX Cap, which we
calculate to be 494,899 tons. In ensuring that total NOX
emissions over 2009-2044 from NGS remain below the 2009-2044
NOX Cap, the TWG Alternative meets the criteria of our
proposed ``better than BART'' framework.
    EPA's technical evaluation has also focused on whether the four
potential operating scenarios in the TWG Alternative (Alternatives A1-
A3 and B) provide a reasonable basis to ensure the NOX
emissions will remain below the 2009-2044 NOX Cap of 494,899
tons.
    The four possible operating scenarios under the TWG Alternative
(Alternatives A1, A2, A3, and B) are summarized in section III.A of
this Supplemental Proposal. These four scenarios are also shown in
Table 3 and compared against the 2009-2044 NOX Cap. The
2009-2044 NOX Cap reflects the final rule effective date
that EPA estimates is reasonable and justified for this rulemaking
(July 1, 2014), resulting in a BART compliance date of July 1, 2019. As
discussed above, the 2009-2044 NOX Cap incorporates the LNB/
SOFA early installation credit. EPA calculates the 2009-2044
NOX Cap to be 494,899 tons.
    The three operating scenarios under Alternative A represent
emission reductions that occur during three distinct periods of time:
over 2009-2011 (through the early installation of LNB/SOFA), by 2020
(from closure or curtailment of one unit, and by 2031 (through
compliance with a NOX limit of 0.07 lb/MMBtu on two units).
Similarly, Alternative B represents emission reduction that would occur
during three distinct periods of time: over 2009-2011 (through the
early installation of LNB/SOFA), any time prior to 2029 (to maintain
compliance with the 2009-2029 NOX Cap), and any time between
2029 and 2044 (to maintain compliance with the 2009-2044 NOX
Cap).
    EPA notes that the closure or curtailment of one unit at NGS in
2020 would result not only in NOX reductions, but also in
reductions of other criteria and hazardous air pollutants, such as
sulfur dioxide (SO2), particulate matter, and mercury.
---------------------------------------------------------------------------

    \35\ Graphical representation of these Alternatives against the
2009-2044 NOX Cap are shown in Spreadsheet titled
``Supplemental Better than BART Alternatives.xlsx'' in the docket
for this proposed rulemaking.

                                                Table 3--Summary of EPA Analysis of TWG Alternative \35\
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        TWG Alternative: Maintain Emissions below 2009-2044 NOX Cap using one of the following
                                                                          operating scenarios:
                                    --------------------------------------------------------------------------------------------------------------------
                                                                       A1                      A2                     A3                     B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ownership Possibilities If:          LADWP and NV Energy exit without selling ownership interest or by      LADWP or NV Energy
                                      selling to an existing NGS Participant.                                exits by selling to
                                                                                a 3rd party, or
                                                                                LADWP or NV Energy
                                                                                do not exit NGS..
--------------------------------------------------------------------------------------------------------------------------------------------------------
And:                                                         Navajo Nation does not  Navajo Nation          Navajo Nation
                                                              purchase ownership      purchases interest     purchases interest
                                                              interest.               (up to 170 MW).        (up to 170 MW).
--------------------------------------------------------------------------------------------------------------------------------------------------------
And:                                                                                Owners increase        Owners do not
                                                                                capacity (does not     increase capacity
                                                                                trigger permit).       (triggers permit).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Summary of Cap or Operating          2009-2044 NOX Cap =     By 12/31/2019, close    By 12/31/2019, close   Three units could      Maintain total NOX
 Scenarios.                           494,899 tons: By 7/1/   one unit.               one unit.              remain open..          emissions below a
                                      2019, meet limit of    By 12/31/2030, meet     By 12/31/2019,         By 12/31/2019,          2009-2029 NOX Cap
                                      0.055 lb/MMBtu          NOX limit of 0.07 lb/   increase net           curtail generation     (416,865 tons). Cap
                                      through installation    MMBtu on two units..    capacity by no more    by at least 561 MW..   is equivalent to
                                      of LNB/SOFA                                     than 189 MW..         By 12/31/2030, meet     closure of one unit
                                      concurrently with                              By 12/31/2030, meet     NOX limit of 0.07 lb/  by 12/31/2019.
                                      SCR.                                            NOX limit of 0.07 lb/  MMBtu on two units..
                                                                                MMBtu on two units..
--------------------------------------------------------------------------------------------------------------------------------------------------------

Estimate of Total NOX over 2009-2044.......................  435,819 tons..........                  461,816 tons                  NGS must ensure total
                                                                                emissions remain
                                                                                below both Caps.
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In order to better understand whether the three potential operating
scenarios under Alternative A provide reasonable assurance that
emissions from NGS will remain below the 2009-2044 NOX Cap,
EPA estimated annual NOX emissions for each potential
operating scenario.\36\ These estimates were based on the specific
requirements for each scenario and the average heat input and average
emission rates for each unit operating with LNB/SOFA.\37\ EPA used
actual emission data, as reported to the EPA Clean Air Markets Program,
for 2001-2012.\38\ To estimate tons of NOX emitted in the
future, EPA calculated the product of annual heat input (in MMBtu/year)
and the annual average NOX emission rate (in lb/MMBtu). In
Table 3, estimates for total NOX emissions over 2009-2044
were calculated based on the average annual heat input over 2001-2012,
and the average annual NOX emission rate achieved over 2011-
2012 (when all three units were operating with LNB/SOFA) for the 2013-
2018 period, and 0.07 lb/MMBtu for the 2020-2044 period.
---------------------------------------------------------------------------

    \36\ Id.
    \37\ Under EPA PSD permit AZ 08-01, November 20, 2008, Units 1-3
at NGS operate with modern LNB/SOFA with an emission limit of 0.24
lb/MMBtu. See documents within EPA-R09-OAR-2013-0009-0005.
    \38\ Id. See also http://ampd.epa.gov/ampd/.
---------------------------------------------------------------------------

    As shown in Table 3, estimates for total NOX emissions
over 2009-2044 for Alternatives A1, A2, and A3 are all below the 2009-
2044 NOX Cap. This indicates that under TWG Alternative A,
NGS can be reasonably expected to remain below the 2009-2044
NOX Cap. The TWG Alternative requires the operator of NGS to
submit an annual report to EPA, which it must also make publicly
available, that includes annual emissions of SO2 and
CO2, and annual and cumulative emissions of NOX.
In addition, EPA is including a provision to require reporting of
annual heat input at NGS to assess operation and utilization of
capacity at NGS.
    Consistent with 40 CFR 51.308(e), the enforceable 2009-2044
NOX Cap will ensure that total emissions of NOX
are less than those that would be emitted under our proposed BART
determination. The weight of evidence, including the operating
scenarios and annual reporting requirements as discussed above, suggest
that NGS can be reasonably expected to remain below the 2009-2044
NOX Cap.
    As indicated in Table 3, and as discussed previously, the operating
scenario under TWG Alternative B does not specify the exact process
that would be used to comply with the 2009-2044 NOX Cap. To
ensure that NOX emission reductions are achieved under TWG
Alternative B in a manner similar to TWG Alternative A1-A3, the TWG
Alternative imposes a nested NOX emission cap for the 2009-
2029 period (the 2009-2029 NOX Cap) that would apply in
addition to the 2009-2044 NOX Cap. Under TWG Alternative B,
the 2009-2029 NOX Cap would be equivalent to total
NOX emissions over 2009-2029 that would be achieved under
TWG Alternative A1, i.e., closure of one unit by December 31, 2019.
Thus, under TWG Alternative B, NGS must still reduce NOX
emissions over 2009-2029 and 2030-2044 in order to comply with the
2009-2029 and 2009-2044 NOX Caps, but the operator would
have flexibility to determine the timing and method of reducing
emissions.
    To evaluate TWG Alternative B, EPA estimated potential emission
reduction timeframes that would be needed to comply with the 2009-2029
and 2009-2044 NOX Caps assuming the owners of NGS elect to
install SCR on all three units at NGS.\39\ Using the average annual
heat input over 2001-2012, and the average annual NOX
emission rate achieved over 2011-2012 (when all three units were
operating with LNB/SOFA), if NGS achieves emission rates of 0.07 lb/
MMBtu or below after installation of SCR, the owners of NGS would need
to install SCR on one unit each in 2026, 2027, and 2028 in order to
comply with the 2009-2029 and 2009-2044 NOX Caps. If NGS
achieves emission rates of 0.055 lb/MMBtu or below, the owners of NGS
would need to install SCR on one unit each in 2028, 2029, and 2030 in
order to comply with the 2009-2029 and 2009-2044 NOX Caps.
In addition to the option of installing SCR on each unit, under TWG
Alternative B, the owners of NGS could elect to implement any operating
scenario (including curtailment, installation of other technologies to
reduce emissions of NOX, or a combination of options or
technologies) as long as the operational changes result in reduced
emissions of NOX sufficient to maintain emissions below the
applicable NOX Cap.
---------------------------------------------------------------------------

    \39\ Although Alternative B does not specify how the caps will
be maintained, installation of SCR on all units at NGS is a
reasonable compliance option, and therefore, EPA is using this as an
example for further examination of Alternative B. See spreadsheet,
titled ``Supplemental Better than BART Alternatives.xlsx''.
---------------------------------------------------------------------------

    To ensure compliance, the annual reporting requirements that apply
to TWG Alternative A would also apply under TWG Alternative B. In
addition, if TWG Alternative B is triggered, the operator of NGS would
be required to submit annual Emission Reduction Plans to EPA that would
identify the potential emission reductions measures and operating
scenarios to comply with the 2009-2029 or 2009-2044 NOX
Caps. Each potential operating scenario in each annual Emission
Reduction Plan must show compliance with the applicable NOX
Cap.
    Consistent with 40 CFR 51.308(e), the enforceable 2009-2029 and
2009-2044 NOX Caps will ensure that total emission
reductions of NOX are greater than those that would be
achieved under our proposed BART determination. The weight of evidence,
including possible operating scenarios and the reporting requirements
as discussed above, indicate that NGS can be reasonably expected to
remain below the 2009-2029 and 2009-2044 NOX Caps.
    Based on our analysis of the operating scenarios under TWG
Alternatives A1-A3 and B, EPA is proposing to determine that the TWG
Alternative meets EPA's ``better than BART'' framework outlined in our
February 5, 2013 proposed BART determination for NGS.

IV. EPA's Supplemental Proposal

    In addition to our proposed BART determination and Alternative 1
for NGS dated February 5, 2013, in today's action, EPA is supplementing
our proposal with the TWG Alternative submitted to EPA on July 26, 2013
as an additional ``better than BART'' Alternative. Because we are
supplementing our February 5, 2013 proposed rulemaking with today's

proposal, after considering public comments, EPA may finalize
provisions from either or both proposals, i.e., our proposed BART
determination, proposed Alternative 1, or the TWG Alternative.
    EPA is proposing to determine that the TWG Alternative ensures that
total emissions of NOX from NGS over 2009-2044 will remain
below the total emissions from NGS over 2009-2044 that would have
occurred under BART. In today's action, EPA is proposing to establish
enforceable requirements to comply with the proposed 2009-2044
NOX Cap, and if applicable, a 2009-2029 NOX Cap,
including annual reporting requirements related to heat input,
emissions of SO2 and CO2, and annual and
cumulative emissions of NOX. In addition, if the final
ownership outcome triggers the operating scenarios under Alternatives
A1-A3, EPA is proposing to establish the emission reduction milestones
under A1-A3 (closure of one unit or curtailment of electricity
generation by December 31, 2019, and installation of SCR on two units
by December 31, 2030) as enforceable requirements. If the final
ownership outcome triggers Alternative B, EPA is proposing to require
the owners of NGS to submit annual Emission Reduction Plans to EPA to
achieve the NOX emission reductions necessary to assure
compliance with the 2009-2029 and 2009-2044 NOX Caps. EPA is
also proposing to require the owners of NGS to notify EPA no later than
December 1, 2019, of the final ownership outcome and the resulting
applicable operating scenario that it will implement. For the reasons
outlined above, EPA is supplementing our February 5, 2013 proposed
rulemaking to also propose the TWG Alternative as a ``better than
BART'' Alternative that ensures greater reasonable progress towards the
national visibility goal than BART.
    EPA is accepting public comment concurrently on our February 5,
2013 proposed BART determination and proposed Alterative 1 and the TWG
Alternative put forth in today's Supplemental Proposal. From November
12-15, 2013, EPA will be holding five open house and public hearing
events throughout Arizona to accept written and oral comment on our
proposed rulemaking and Supplemental Proposal. The comment period for
our February 5, 2013 proposed rulemaking and today's Supplemental
Proposal closes on January 6, 2014.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review 13563

    This action supplements our proposed source-specific Federal
Implementation Plan for the Navajo Generating Station to propose and
take comment on an additional Alternative to BART that was developed by
and agreed upon by a group of seven stakeholders. Under the terms of
Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and EO 13563
(76 FR 3821, January 21, 2011), because this proposed rule applies to
only one facility, it is not a rule of general applicability. This
proposed rule, therefore, is exempt from review under EO 12866 and EO
13563.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.
Burden is defined at 5 CFR 1320.3(b). 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 Supplemental Proposal applies to a single facility, Navajo
Generating Station, the Paperwork Reduction Act does not apply.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's proposed rule on
small entities, small entity is defined as: (1) a small business as
defined by the Small Business Administration's (SBA) regulations at 13
CFR 121.201; (2) a small governmental jurisdiction that is a government
of a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
    After considering the economic impacts of this proposed action on
small entities, I certify that this proposed 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 proposed today does not impose any
compliance requirements on small entities. See Mid-Tex Electric
Cooperative, Inc. v. FERC, 773 F.2d 327 (D.C. Cir. 1985). We continue
to be interested in the potential impacts of the proposed rule and this
Supplemental Proposal on small entities and welcome comments on issues
related to such impacts.

D. Unfunded Mandates Reform Act (UMRA)

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2
U.S.C. 1531-1538, requires Federal agencies, unless otherwise
prohibited by law, to assess the effects of their regulatory actions on
State, local, and tribal governments and the private sector. Federal
agencies must also develop a plan to provide notice to small
governments that might be significantly or uniquely affected by any
regulatory requirements. The plan must enable officials of affected
small governments to have meaningful and timely input in the
development of EPA regulatory proposals with significant Federal
intergovernmental mandates and must inform, educate, and advise small
governments on compliance with the regulatory requirements.
    This rule does not contain a Federal mandate that may result in
expenditures of $100 million or more for state, local, and tribal
governments, in the aggregate, or the private sector in any one year.
EPA anticipates the annual cost to the private sector of this
Supplemental Proposal, which involves compliance with BART emission
limits by two units, rather than three units, to be lower than the
anticipated cost of EPA's proposed BART determination of $64 million
per year (see Table 2 of EPA's proposed BART determination at 78 FR
8274, February 5, 2013). Thus, this Supplemental Proposal is not
subject to the requirements of sections 202 or 205 of UMRA. This
proposed rule will not impose direct compliance costs on state, local
or tribal governments. This proposed action will, if finalized, reduce
the emissions of NOX from a single source, the Navajo
Generating Station.
    In developing this rule, EPA consulted with small governments
pursuant to a plan established under section 203 of UMRA to address
impacts

of regulatory requirements in the rule that might significantly or
uniquely affect small governments. EPA put forth an Advanced Notice of
Proposed Rulemaking on August 28, 2009 regarding our intention to
propose a BART determination for NGS and the Four Corners Power Plant.
We received comments from numerous small governments, including tribal
governments, and governments of several towns in Arizona. This proposed
rule will not impose direct compliance costs on any small governments.
However, increased electricity and water costs associated with this
proposed rule may indirectly affect small governments.

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 action proposes emission
reductions of NOX at a specific stationary source located in
Indian country. Thus, Executive Order 13132 does not apply to this
action.

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

    Under 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.
    EPA has concluded that this proposed action will have tribal
implications, and consequently EPA has consulted with tribal officials
during the process of developing the proposed regulation and will
continue to consult with tribal officials during the process to take
final action. EPA notes that the TWG Alternative, on which this
Supplemental Proposal is based, was developed by a group of seven
stakeholders that included the Navajo Nation and the Gila River Indian
Community. However, we also note that not all tribes that may be
affected by this proposed alternative were among the stakeholders.
Other tribes may have views on this alternative and EPA welcomes their
comments. The proposed regulation will not pre-empt tribal law. The
proposed regulation will also not impose direct compliance costs on a
tribal government, because the direct compliance costs of this proposed
rule, if finalized, will be borne by the owners of NGS. However,
because several tribes located in Arizona rely directly or indirectly
on NGS, there may be indirect impacts of this proposed rule on these
tribes. The Navajo Nation and Hopi Tribe receive coal-related
royalties, taxes and employment at NGS and the Kayenta Mine that
contribute to their economies. Several tribes in Arizona have
allocations of CAP water under existing water settlement agreements.
Because of the inter-relationship of CAP and NGS, impacts to NGS may
also impact CAP and the tribes that use CAP water or otherwise benefit
from CAP according to Congressionally-approved water settlement
agreements. The importance to tribes of continued operation of NGS and
affordable water costs cannot be overemphasized. In Section II.B.ii of
EPA's proposed BART determination dated February 5, 2013 (78 FR8274),
EPA explains in detail the tribal information that we received and
considered in this proposed rulemaking.
    In addition to our consultation with tribes discussed in our
February 5, 2013 proposed rulemaking, EPA has had additional meetings
and conference calls with tribes at their request since the time we
received the TWG Alternative, and during our process of evaluating the
TWG Alternative. On August 22, 2013, we met with Governor Gregory
Mendoza and other representatives from the Gila River Indian
Community.\40\ On August 28, 2013, EPA met with President Ben Shelly
and other representatives from the Navajo Nation.\41\ We held a
conference call on September 13, 2013 with Chairman LeRoy Shingoitewa
and another representative from the Hopi Tribe.\42\ Chairman
Shingoitewa also submitted a letter to EPA, dated August 19, 2013,
expressing several concerns related to the TWG Alternative.\43\ An
updated timeline of all correspondence and consultation with tribes on
NGS is included in the docket for this proposed rulemaking.\44\
---------------------------------------------------------------------------

    \40\ See document number 0152 in the docket for the proposed
rulemaking at EPA-R09-OAR-2013-0009.
    \41\ See document number 0150 in the docket for the proposed
rulemaking at EPA-R09-OAR-2013-0009.
    \42\ See document number 0166 in the docket for the proposed
rulemaking at EPA-R09-OAR-2013-0009.
    \43\ See document number 0134 in the docket for the proposed
rulemaking at EPA-R09-OAR-2013-0009.
    \44\ See document titled ``Timeline of All Tribal Consultations
on Navajo BART FIPs as of September 17 2013'' in the docket for this
proposed rulemaking.
---------------------------------------------------------------------------

    EPA recognizes that the Navajo Nation and the Gila River Indian
Community participated in the development of the TWG Agreement on NGS
and were signatories on the Agreement. However, EPA also understands
from discussions with President Shelly and Governor Mendoza that
concerns, related to potential impacts to their respective tribes from
BART and the TWG Alternative, still exist. EPA understands that
Chairman Shingoitewa has numerous concerns related to the TWG Agreement
and Alternative, including the exclusion of the Hopi Tribe from the TWG
and the development of the TWG Agreement, and the extended timeframe
for the installation of new air pollution controls at NGS under the TWG
Alternative. EPA will continue to consult with Tribal officials during
and following the public comment period on the proposed FIP.

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
proposed rule is not subject to Executive Order 13045 because it
requires emissions reductions of NOX from a single
stationary source. Because this proposed action only applies to a
single source and is not a proposed rule of general applicability, it
is not economically significant as defined under Executive Order 12866,
and does not have a disproportionate effect on children. However, to
the extent that the rule will reduce emissions of NOX, which
contribute to ozone and fine particulate matter formation as well as
visibility impairment, 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 exempt 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 requirements. It
would not be practical to specify these standards in the current
proposed 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 proposed rule, if finalized, will not
have disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it increases the
level of environmental protection for all affected populations without
having any disproportionately high and adverse human health or
environmental effects on any population, including any minority or low-
income population. This proposed rule requires emissions reductions of
NOX from a single stationary source, Navajo Generating
Station.

List of Subjects in 40 CFR Part 49

    Environmental protection, Air pollution control, Indians,
Intergovernmental relations, Nitrogen Dioxide.

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

    Dated: September 25, 2013.
Jared Blumenfeld,
Regional Administrator, Region 9.

    Title 40, chapter I of the Code of Federal Regulations is proposed
to be amended as follows:

PART 49--[AMENDED]

0
1. The authority citation for part 49 continues to read as follows:

    Authority:  42 U.S.C. 7401, et seq.
0
2. Section 49.5513 is amended by adding paragraph (j) to read as
follows:

Sec.  49.5513  Federal Implementation Plan Provisions for Navajo
Generating Station, Navajo Nation.

* * * * *
    (j) (1) Applicability. Regional Haze Best Available Retrofit
Technology limits 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), shall not be affected thereby.
Nothing in this paragraph (j) allows or authorizes any Unit to emit
NOX at a rate that exceeds its existing emission limit of
0.24 lb/MMBtu as established by EPA permit AZ 08-01 issued on November
20, 2008.
    (2) Definitions. Terms not defined below shall have the meaning
given to them in the Clean Air Act or EPA's regulations implementing
the Clean Air Act and in paragraph (c) of this section. For purposes of
this paragraph (j):
    (i) 2009-2029 NOX Cap is no more than 416,865 tons of
NOX. This value is calculated based on the sum of annual
emissions over January 1, 2009 to December 31, 2029, and closure of one
unit by December 31, 2019.
    (ii) 2009-2044 NOX Cap is no more than 494,899 tons of
NOX. This value is calculated based on the sum of annual
emissions over January 1, 2009 to December 31, 2044, and compliance
with a BART emission limit of 0.055 lb/MMBtu on each Unit by July 1,
2019.
    (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.
    (vi) Emission limitation or emission limit means the federal
emissions limitation required by this paragraph.
    (vii) Existing Participant means the existing owners of NGS: Los
Angeles Department of Water and Power; Nevada Energy, also known as NV
Energy or Nevada Power Company; Salt River Project Agricultural
Improvement and Power District; Arizona Public Service Company; and
Tucson Electric Company, together with the United States, acting
through the Bureau of Reclamation.
    (ix) lb means pound(s).
    (x) Low-NOX Burners and Separated Over-Fire Air or LNB/SOFA means
combustion controls installed on one Unit each over 2009-2011.
    (xi) Navajo Nation means the Navajo Nation, a federally recognized
Indian Tribe.
    (xii) NGS or Navajo Generating Station means the steam electric
generating station located on the Navajo Reservation near Page,
Arizona, consisting of Units 1, 2, and 3, each 750

MW (nameplate rating), the switchyard facilities, and all facilities
and structures used or related thereto.
    (xiii) NOX means nitrogen oxides expressed as nitrogen dioxide
(NO2).
    (xiv) Owner(s)/operator(s) 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) BART Determination. BART for NGS is a NOX emission
limit of 0.055 lb/MMBtu on each Unit with a compliance date of July 1,
2019, and is used to establish a cap in NOX emissions, known
as the 2009-2044 NOX Cap. The owner/operator shall
demonstrate BART compliance by ensuring that total NOX
emissions from NGS, over January 1, 2009 to December 31, 2044, do not
exceed the 2009-2044 NOX Cap. The owner/operator shall
implement the applicable operating scenario, under paragraph (j)(3)(i),
to ensure NOX emission reductions sufficient to maintain
total NOX emissions below the 2009-2044 NOX Cap.
    (i) Operating Scenarios to Comply with 2009-2044 NOX Cap.
    (A) Alternative A1.
    (1) By December 31, 2019, the owner/operator shall permanently
cease operation of one coal-fired Unit.
    (2) By December 31, 2030, the owner/operator shall comply with a
NOX emission limit of 0.07 lb/MMBtu on each of the two
remaining coal-fired Units.
    (B) Alternative A2.
    (1) By December 31, 2019, the owner/operator shall permanently
cease operation of one coal-fired Unit.
    (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 by the sum of 19 MW and the
ownership interest, in net MW capacity, purchased by the Navajo Nation
by December 31, 2019. The owner/operator shall ensure that any increase
in the net generating capacity is in compliance with all pre-
construction permitting requirements, as applicable.
    (3) By December 31, 2030, the owner/operator shall comply with a
NOX emission limit of 0.07 lb/MMBtu on each of the two
remaining coal-fired Units.
    (C) Alternative A3.
    (1) By December 31, 2019, the owner/operator shall 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,
purchased by the Navajo Nation by December 31, 2019.
    (2) By December 31, 2030, the owner/operator shall comply with a
NOX emission limit of 0.07 lb/MMBtu on two Units.
    (D) Alternative B. In addition to the 2009-2044 NOX Cap
that applies between January 1, 2009 to December 31, 2044, during the
January 1, 2009 to December 31, 2029 period, the owner/operator shall
ensure compliance with the 2009-2029 NOX Cap.
    (ii) Applicability of Alternatives.
    (A) Alternative A1 shall apply if both of the Departing
Participants retire their ownership interests in NGS by December 31,
2019, and the Navajo Nation does not purchase an ownership share of NGS
by December 31, 2019; or if both of the Departing Participants sell
their ownership interests to Existing Participants, and the Navajo
Nation does not purchase an ownership share of NGS by December 31,
2019; or if one of the Departing Participants retires its ownership
interest and the other Departing Participant sells its ownership
interest to an Existing Participant, and the Navajo Nation does not
purchase an ownership share of NGS by December 31, 2019.
    (B) Alternative A2 shall apply if both of the Departing
Participants sell their ownership interests to Existing Participants,
the Navajo Nation elects to purchase an ownership share of NGS by
December 31, 2019, and the owner/operator elects to increase net
generating capacity of the two remaining Units; or if one of the
Departing Participants retires its ownership interest and the other
Departing Participant sells its ownership interest to an Existing
Participant, the Navajo Nation elects to purchase an ownership share of
NGS by December 31, 2019, and the owner/operator elects to increase net
generating capacity of the two remaining Units.
    (C) Alternative A3 shall apply if both of the Departing
Participants sell their ownership interests to Existing Participants,
the Navajo Nation elects to purchase an ownership share of NGS by
December 31, 2019, and the owner/operator does not elect to increase
net generating capacity; or if one of the Departing Participants
retires its ownership interest and the other Departing Participant
sells its ownership interest to an Existing Participant, the Navajo
Nation elects to purchase an ownership share of NGS by December 31,
2019, and the owner/operator does not elect to increase net generating
capacity.
    (D) Alternative B shall apply if, by December 31, 2019, any of the
Departing Participants sell their ownership interests to a Party that
is not an Existing Participant.
    (4) Reporting and Implementation Requirements for BART.
    (i) No later than December 1, 2019, the owner/operator must notify
EPA of the applicable Alternative for ensuring compliance with the
2009-2044 NOX Cap.
    (ii) Beginning January 31, 2015, and annually thereafter until the
earlier of December 22, 2044 or the date on which the owner/operator
ceases conventional coal-fired generation at NGS, the owner/operator
shall submit to the Regional Administrator, a report summarizing the
annual heat input, the annual emissions of sulfur dioxide, carbon
dioxide, and annual and cumulative emissions of NOX from NGS
for the previous full calendar year. The owner/operator shall make this
report available to the public, either through a link on its Web site
or directly on its Web site.
    (iii) No later than December 31, 2020, the owner/operator shall
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).
    (iv) In addition to the requirements of paragraphs (j)(4)(i), (ii)
and (iii), if Alternative B applies, the owner/operator shall submit
annual Emission Reduction Plans to the Regional Administrator.
    (A) No later than December 31, 2019 and annually thereafter through
December 31, 2028, the owner/operator shall submit an Emission
Reduction Plan containing anticipated year-by-year emissions covering
the period from 2020 to 2029 that will assure that the operation of NGS
will result in emissions of NOX that do not exceed the 2009-
2029 NOX Cap. The Emission Reduction Plan may contain
several potential operating scenarios and must set forth the past
annual actual emissions and the projected emissions for each potential
operating scenario. Each potential operating scenario must demonstrate
compliance with the 2009-2029 NOX Cap. The Emission
Reduction Plan shall identify emission reduction measures that may
include, but are not

limited to, the installation of advanced emission controls, a reduction
in generation output, or other operating strategies determined by the
owner/operator. The owner/operator may revise the potential operating
scenarios set forth in the Emission Reduction Plan, provided the
revised plan ensure that NOX emissions remain below the
2009-2029 NOX Cap.
    (B) No later than December 31, 2029 and annually thereafter, the
owner/operator shall submit an Emission Reduction Plan containing year-
by-year emissions covering the period from January 1, 2030 to December
31, 2044 that will assure that the operation of NGS will result in
emissions of NOX that do not exceed the 2009-2044
NOX Cap. The Emission Reduction Plan shall identify emission
reduction measures that may include, but are not limited to, the
installation of advanced emission controls, a reduction in generation
output, or other operating strategies determined by the owner/operator.
The owner/operator may revise the potential operating scenarios set
forth in the Emission Reduction Plan, provided the revised plan ensure
that NOX emissions remain below the 2009-2044 NOX
Cap.
    (5) Continuous emission monitoring system (CEMS).
    (i) At all times, the owner/operator of each unit shall maintain,
calibrate, and operate a CEMS, in full compliance with the requirements
found at 40 CFR Part 75, to accurately measure NOX, diluent,
and stack gas volumetric flow rate from each unit. Valid data means
data recorded when the CEMS is not out-of-control as defined by Part
75, as defined in paragraph (j)(2) of this section. All valid CEMS
hourly data shall be used to determine compliance with the emission
limitations for NOX in paragraph (j)(3) of this section for
each unit. If the CEMs data is not valid, that CEMs data shall be
treated as missing data and not used to calculate the emission average.
CEMs data does not need to be bias adjusted as defined in 40 CFR Part
75. Each required CEMS must obtain valid data for at least 90 percent
of the unit operating hours, on an annual basis.
    (ii) The owner/operator of each unit shall comply with the quality
assurance procedures for CEMS found in 40 CFR Part 75. In addition to
these Part 75 requirements, relative accuracy test audits shall be
calculated for both the NOX pounds per hour measurement and
the heat input measurement. The calculation of NOX pounds
per hour and heat input relative accuracy shall be evaluated each time
the CEMS undergo relative accuracy testing.
    (6) Compliance Determination for NOX Emission Limits.
    (i) Compliance with the NOX emission limits under
paragraphs (j)(3)(i) 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: (1) Sum
the total pounds of NOX emitted from the Unit during the
current Boiler Operating Day and the previous twenty-nine (29) Boiler
Operating Days; (2) 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 (3) divide the total number of pounds
of NOX by the total heat input in MMBtu during the thirty
(30) Boiler Operating Days. A new 30 Boiler Operating Day rolling
average shall be calculated for each new Boiler Operating Day. Each 30
Boiler Operating Day rolling average shall include all emissions that
occur during periods within any Boiler Operating Day, including
emissions from startup, shutdown, and malfunction.
    (ii) If a valid NOX pounds per hour or heat input is not
available for any hour for a unit, that heat input and NOX
pounds per hour shall not be used in the calculation for that 30 boiler
operating day period.
    (7) Recordkeeping. The owner or operator of each unit shall
maintain the following records for at least five years:
    (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 unit's pounds of
NOX and heat input for each hour.
    (ii) Each calendar day rolling average group emission rates for
NOX calculated in accordance with paragraph (j)(6)(i) of
this section.
    (iii) Each unit's 30 Boiler Operating Day pounds of NOX
and heat input.
    (iv) Records of quality assurance and quality control activities
for emissions measuring systems including, but not limited to, any
records required by 40 CFR Part 75.
    (v) Records of the relative accuracy calculation of the
NOX lb/hr measurement and hourly heat input.
    (vi) Records of all major maintenance activities conducted on
emission units, air pollution control equipment, and CEMS.
    (vii) Any other records required by 40 CFR Part 75.
    (8) Reporting. All reports and notifications under this paragraph
(j) shall 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 shall notify EPA within two weeks after
completion of installation of NOX control technology on any
of the units subject to this section.
    (ii) Within 30 days after the first applicable compliance date in
paragraph (j)(3) of this section and within 30 days of every second
calendar quarter thereafter (i.e., semi-annually), the owner/operator
shall submit a report that lists for each calendar day, calculated in
accordance with paragraph (j)(6) of this section, total lb of
NOX and heat input (as used to calculate compliance per
paragraph (j)(6), for each unit's last 30 boiler operating days.
Included in this report shall be the results of the last relative
accuracy test audit and the calculated relative accuracy for lb/hr
NOX and heat input performed 45 days prior to the end of
that reporting period. The end of the year report shall also include
the percent valid data for each NOX, diluent, and flow
monitor used in the calculations of compliance with paragraph (j)(6).
    (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 or operator shall, to the
extent practicable, 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)(1) and (g)(3) of this

section, related only to malfunctions, apply to this paragraph (j).

[FR Doc. 2013-24281 Filed 10-21-13; 8:45 am]
BILLING CODE 6560-50-P