[Federal Register Volume 82, Number 57 (Monday, March 27, 2017)]
[Rules and Regulations]
[Pages 15139-15154]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-05724]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2016-0292; FRL-9958-79-Region 9]
Approval and Revision of Air Plans; Arizona; Regional Haze State
and Federal Implementation Plans; Reconsideration
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is taking final
action to approve a source-specific revision to the Arizona state
implementation plan that addresses the best available retrofit
technology requirements for the Cholla Power Plant (Cholla). The EPA
finds that the state implementation plan revision fulfills the
requirements of the Clean Air Act and the EPA's Regional Haze Rule. In
conjunction with this final approval, the EPA is taking final action to
withdraw the federal implementation plan provisions applicable to
Cholla. This also constitutes our action to address petitions for
reconsideration granted by the EPA related to Cholla.
DATES: This rule is effective on April 26, 2017.
ADDRESSES: The EPA has established a docket for this action, identified
by Docket ID Number EPA-R09-OAR-2016-0292. The index to the docket is
available electronically at http://www.regulations.gov or in hard copy
at the EPA Region IX office, 75 Hawthorne Street, San Francisco,
California. While all documents in the docket are listed in the index,
some information may be publicly available only at the hard copy
location (e.g., copyrighted material), and some may not be publicly
available in either location (e.g., confidential business information).
To inspect the hard copy materials, please schedule an appointment
during normal business hours with the contact listed below.
FOR FURTHER INFORMATION CONTACT: Anita Lee, (415) 972-3958, or by email
at [email protected].
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
Table of Contents
I. Background
II. Public Comments and the EPA's Response to Comments
A. Comments on the BART Reassessment
B. Comments on Visibility Benefits
C. Comments on the CAA Section 110(l) Analysis
D. Other Comments
III. Summary of Final Action
IV. Environmental Justice Considerations
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews
I. Background
On July 19, 2016, the EPA proposed to approve the source-specific
regional haze state implementation plan (SIP) revision for the Cholla
Power Plant (``Cholla SIP Revision'') submitted to the EPA by the
Arizona Department of Environmental Quality (ADEQ).\1\ The EPA
concurrently proposed to withdraw federal implementation plan (FIP)
provisions applicable to Cholla and proposed that the FIP withdrawal
would constitute the EPA's action on petitions for reconsideration of
the FIP.
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\1\ See 81 FR 46852, July 19, 2016.
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This section provides a brief overview of the statutory and
regulatory background for this action. Please refer to the proposed
rule for additional discussion of the visibility protection provisions
of the Clean Air Act (CAA or ``Act'') and the Regional Haze Rule (RHR),
and the EPA's evaluation of the regional haze SIP revision for
Cholla.\2\
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\2\ Id.
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In section 169A of the 1977 Amendments to the CAA, Congress created
a program to protect visibility in the nation's national parks and
wilderness areas. This section of the CAA established as a national
goal the ``prevention of any future, and the remedying of any existing,
impairment of visibility in mandatory Class I Federal areas which
impairment results from manmade air pollution,'' and directed states to
evaluate the best available retrofit technology (BART) to address
visibility impairment from certain categories of major stationary
sources built between 1962 and 1977 (known as ``BART-eligible''
sources).\3\ In the 1990 CAA Amendments, Congress amended the
visibility provisions of the CAA to focus attention on the problem of
regional haze, i.e., visibility impairment produced by a multitude of
sources and activities located across a broad geographic area.\4\
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\3\ See CAA section 169A(a)(1).
\4\ See CAA section 169B.
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In 1999, the EPA promulgated the RHR that required states to, among
other things, conduct an analysis to determine BART for each BART-
eligible source that may be anticipated to cause or contribute to
visibility impairment in a Class I area.\5\ States must analyze and
consider the following five factors as part of each source-specific
BART analysis: (1) The costs of compliance, (2) the energy and nonair
quality environmental impacts of compliance, (3) any existing pollution
control technology in use at the source, (4) the remaining useful life
of the source, and (5) the degree of visibility improvement that may
reasonably be anticipated to result from use of such technology
(collectively known as the ``five-factor BART analysis'').\6\ In
determining BART for fossil fuel-fired electric generating plants with
a total generating capacity in excess of 750 megawatts (MW), states
must use guidelines promulgated by the EPA.\7\ In 2005, the EPA
published the
[[Page 15140]]
current version of the ``Guidelines for BART determinations under the
Regional Haze Rule,'' codified at appendix Y to 40 CFR part 51 (``BART
Guidelines'').\8\
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\5\ 40 CFR 51.308(e).
\6\ See CAA section 169A(g)(2) and the RHR at 40 CFR
51.308(e)(1)(ii)(A).
\7\ See CAA section 169A(b)(1) and the last sentence of 169A(b).
\8\ See 70 FR 39104, July 6, 2005.
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Cholla consists of four coal-fired electric generating units with a
total plant-wide generating capacity of 1150 MW. Unit 1 is a 126 MW
boiler that is not BART-eligible. Unit 2 (272 MW), Unit 3 (272 MW), and
Unit 4 (410 MW) are tangentially-fired dry bottom boilers that are
BART-eligible. Units 1, 2, and 3 are owned and operated by Arizona
Public Service Company (APS). Unit 4 is owned by PacificCorp and
operated by APS.
On February 28, 2011, ADEQ submitted a regional haze SIP under
section 308 of the RHR to the EPA (``2011 RH SIP''). This submittal
included, among other things, BART analyses and determinations for
Cholla Units 2, 3, and 4 for oxides of nitrogen (NOX),
particulate matter with an aerodynamic diameter of less than 10
micrometers (PM10), and sulfur dioxide (SO2).\9\
On December 5, 2012, the EPA took final action that approved in part
and disapproved in part the 2011 RH SIP. The EPA found that ADEQ's
overall approach in conducting its BART analyses was appropriate, but
we also identified significant flaws in the analyses for specific BART
factors that warranted disapproval of the NOX BART
determination for Cholla. Specifically, the EPA found that ADEQ did not
calculate the costs of compliance in accordance with the BART
Guidelines, did not appropriately evaluate and consider the visibility
benefits, did not provide sufficient explanation and rationale for its
final BART determination, and did not include enforceable emission
limits in the SIP.\10\ In the same action, the EPA promulgated a FIP
for the disapproved portions of the SIP, including a NOX
BART determination for Cholla that established an emission limit of
0.055 pound per million British thermal units (lb/MMBtu) determined
across the three units on a rolling 30-boiler-operating-day average,
with a compliance date of December 5, 2017. This limit is achievable
with the combination of low-NOX burners with separated over-
fire air (LNB+SOFA) and selective catalytic reduction (SCR). The FIP
also established an SO2 removal efficiency requirement of 95
percent for Units 2, 3, and 4 with a compliance date for Units 3 and 4
of December 5, 2013, and a compliance date for Unit 2 of April 1, 2016.
Finally, the FIP also established compliance deadlines, compliance
determination methodologies, and requirements for equipment
maintenance, monitoring, recordkeeping, and reporting for
NOX, SO2 and PM10.\11\ On April 9,
2013, the EPA granted petitions to reconsider the compliance
determination methodology for NOX.\12\
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\9\ The 2011 RH SIP submittal is document number 0017 in the
docket for this rulemaking at EPA-R09-OAR-2016-0292, entitled
``B.1.a ADEQ RH 308 SIP 2011-SIP only.''
\10\ See generally, Ariz. Ex rel. Darwin v. U.S. EPA, 815 F.3d
519 (9th Circuit, 2016).
\11\ See 77 FR 72511, December 5, 2012.
\12\ See letter from Jared Blumenfeld, EPA Region IX, to E.
Blaine Rawson, Ray Quinney & Nebeker P.C. (on behalf of PacifiCorp),
dated April 9, 2013; letter from Jared Blumenfeld, EPA Region IX, to
Norman Fichthorn, Hunton and Williams LLP (on behalf of APS), dated
April 9, 2013; and letter from Jared Blumenfeld, EPA Region IX, to
Aaron Flynn, Hunton and Williams LLP (on behalf of APS), dated April
9, 2013.
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On January 15, 2015, APS and PacifiCorp submitted an ``Application
for Significant Permit Revision and Five-Factor BART Reassessment for
Cholla'' to ADEQ. APS and PacifiCorp committed to take specific actions
in lieu of the FIP requirements for Cholla and requested that ADEQ
conduct a revised BART analysis and determination (``BART
Reassessment'') and submit it to the EPA as a revision to the Arizona
RH SIP. Specifically, APS and PacifiCorp committed to (1) permanently
close Cholla Unit 2 by April 1, 2016, (2) continue to operate LNB+SOFA
on Units 3 and 4, and (3) by April 30, 2025, permanently cease burning
coal at both units with the option to convert both units to enable
combustion of pipeline-quality natural gas by July 31, 2025, with an
annual average capacity factor of less than or equal to 20 percent.
On October 22, 2015, ADEQ submitted to the EPA the Cholla SIP
Revision that incorporates the Cholla BART Reassessment. The Cholla SIP
Revision consists of a revised BART analysis and determination for
NOX, an analysis under CAA section 110(l), and revisions to
Cholla's operating permit to implement ADEQ's revised BART
determination for NOX and the commitments by APS and
PacifiCorp related to the retirement and repowering of units.\13\ ADEQ
determined that if APS closed Unit 2 by April 1, 2016, no BART
determination for Unit 2 would be necessary because the enforceable
closure date is within the 5-year window for compliance with BART. For
Units 3 and 4, ADEQ conducted a revised BART analysis in light of the
commitments made by APS and PacifiCorp regarding future operation of
those units. Based on its re-analysis of the BART factors, ADEQ
determined BART for Cholla Units 3 and 4 to be LNB+SOFA when coal is
combusted in those units. In the permit revision submitted as part of
the Cholla SIP Revision, ADEQ established unit-specific emission limits
for Cholla Units 3 and 4 of 0.22 lb/MMBtu, effective until the
permanent cessation of coal burning on April 30, 2025, and an emission
limit of 0.08 lb/MMBtu, effective May 1, 2025 and thereafter, that
would apply if Units 3 or 4 are repowered to natural gas. Although
ADEQ's BART determination for Cholla Units 3 and 4 is LNB+SOFA, the
permit revision for Cholla sets an emission limitation achievable with
this technology, but it does not specify that LNB+SOFA must be used.
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\13\ The Cholla SIP Revision is document number 0019 in the
docket for this rulemaking at EPA-R09-OAR-2016-0292, titled ``B.3.
2015-10-22--Cholla SIP Revision.''
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The EPA's proposed action on the Cholla SIP Revision includes a
comprehensive summary of ADEQ's BART Reassessment for Cholla Units 3
and 4, and the EPA's evaluation of ADEQ's submittal. In this section,
we provide a brief summary of the EPA's evaluation of the Cholla SIP
Revision. Please see the proposed rule for a detailed discussion of
ADEQ's analysis and the EPA's evaluation of it.\14\
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\14\ See 81 FR 46852 at 46854-46863, July 19, 2016.
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In our evaluation of Cholla Unit 2, we noted that the permanent
retirement date of April 1, 2016, in the Cholla SIP Revision coincides
with the compliance deadlines for SO2 and PM10 in
the FIP and precedes the compliance deadline for NOX by over
1 year. The EPA further noted that Unit 2 permanently closed on October
1, 2015.\15\ If Unit 2 had not retired, APS would have been required to
install additional controls to meet the applicable SO2,
PM10, and NOX limits. Because the requirement for
the permanent retirement of Unit 2 will become effective and federally
enforceable when the Cholla SIP Revision is approved into the SIP and
the FIP provisions applicable to Cholla are withdrawn, we proposed
approval of the requirement for permanent retirement of Unit 2 as
meeting the requirements of the CAA and the RHR.
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\15\ See letter from Edward Seal, APS, to Kathleen Johnson, EPA,
and Eric Massey, ADEQ, dated October 28, 2015.
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In our evaluation of Units 3 and 4, we found that ADEQ's BART
Reassessment was consistent with the requirements of the CAA, the RHR,
and the BART Guidelines and that it addressed the flaws that were the
bases for our disapproval of the BART analysis for Cholla.
Specifically, in its 2011 RH SIP,
[[Page 15141]]
ADEQ's cost analysis was flawed because it included certain line item
costs that were inconsistent with the EPA Control Cost Manual (CCM).
This approach did not comply with the direction in the BART Guidelines
to base cost estimates on the CCM. In its BART Reassessment for Cholla,
ADEQ relied on the cost estimates, calculated using the CCM
methodology, that the EPA developed as part of the FIP for Cholla.
In its 2011 RH SIP, ADEQ considered the visibility benefits of
controls on only one unit at a time and overlooked significant benefits
at the multiple Class I areas, thereby understating and not giving
appropriate consideration to the full visibility benefits of the
candidate controls. In its BART Reassessment for Cholla, based on
modeling performed by APS and PacifiCorp, ADEQ evaluated the visibility
impacts and potential improvements from all units together and also
considered potential improvements at all 13 Class I areas within 300
kilometers of Cholla.
As discussed in our proposed rulemaking, the EPA also proposed to
find that ADEQ appropriately considered and weighed the five BART
factors in determining BART for Cholla. We stated that it was
reasonable for ADEQ to conclude that the costs of SCR and selective
noncatalytic reduction (SNCR) were not warranted by the visibility
benefits. Specifically, we noted that we were not aware of any instance
in which the EPA had determined SCR or SNCR to be BART where the
average and incremental cost-effectiveness of those controls equaled or
exceeded the average and incremental cost-effectiveness of those
controls for Cholla Units 3 and 4. Nor were we aware of any instance in
which the EPA disapproved a state's BART determination that rejected
SCR or SNCR as BART based on average and incremental cost-effectiveness
similar to those for Cholla Units 3 and 4. In addition, although we
noted that the visibility benefits of SCR are significant, and the
visibility benefits of SNCR are not insignificant, we determined that
it was reasonable for ADEQ to determine that the benefits were not
warranted given the costs of SCR and SNCR. Moreover, after
approximately 8 years, when Units 3 and 4 cease coal combustion
permanently and are either closed or converted to natural gas, the
benefits of SCR and SNCR would be negligible.
Finally, in our proposed rulemaking, we evaluated the Cholla SIP
Revision with respect to certain other requirements of the CAA and
proposed to find that it would not interfere with attainment of the
national ambient air quality standards (NAAQS), reasonable further
progress, or any other applicable requirement of the CAA. We further
noted that the enforceable emission limitations and the requirements
for monitoring, recordkeeping, and reporting promulgated in the FIP for
Cholla are included in the operating permit revision for Cholla that
ADEQ included with its Cholla SIP Revision. Therefore, these
requirements will remain federally enforceable when the Cholla SIP
Revision is approved and the FIP provisions are withdrawn. Based on our
evaluation of the Cholla SIP Revision, we proposed to approve the SIP
revision, withdraw the FIP provisions, and to find that withdrawal of
the FIP would constitute our action on the petitions for
reconsideration submitted by APS and PacifiCorp.
II. Public Comments and the EPA's Response to Comments
We received four comment letters from the following organizations
prior to the close of the comment period on September 2, 2016: (1) APS,
(2) PacifiCorp, (3) Environmental Defense Fund and Western Resource
Advocates, and (4) Earthjustice on behalf of National Parks
Conservation Association and Sierra Club.\16\
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\16\ See (1) letter from Chas Spell, Arizona Public Service, to
Gina McCarthy, EPA, re: Arizona Public Service Company Comments on
EPA's Proposed Rule Approval and Revision of Air Plans; Arizona;
Regional Haze State and Federal Implementation Plans;
Reconsideration, dated September 1, 2016; (2) letter from William K.
Lawson, Pacificorp, to Vijay Limaye, EPA, re: Docket ID No. EPA-R09-
OAR-2016-0292 Approval and Revision of Air Plans; Arizona; Regional
Haze State and Federal Implementation Plans; Reconsideration
(Proposed Rule), dated September 1, 2016; (3) letter from Bruce
Polkowsky, Graham McCahan, Environmental Defense Fund, and John
Nielsen, Western Resource Advocates to Vijay Limaye, EPA, re:
Comments on the proposed approval of a source-specific revision to
the Arizona Implementation Plan for Best Available Retrofit
Technology at Cholla Generating Station. Docket ID No. EPA-R09-OAR-
2016-0292, undated letter submitted to www.regulations.gov on
September 2, 2016; and (4) letter from Michael Hiatt, Earthjustice
on behalf of Kevin Dahl, Stephanie Kodish, and Nathan Miller,
National Parks Conservation Association, and Sandy Bahr, Bill
Corcoran, and Gloria Smith, Sierra Club, to Vijay Limaye, EPA, re:
Arizona Regional Haze Plan--Cholla BART Reassessment, dated
September 2, 2016.
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A. Comments on the BART Reassessment
Comment 1: One commenter asserted that the BART Reassessment
violates the CAA's mandatory 5-year BART compliance deadline and the
regulatory requirement to achieve visibility improvement in the first
planning period that ends in 2018. In addition, the commenter argued
that the BART Guidelines at appendix Y state that in the event a source
prefers to shut down to comply with BART, the BART requirement must
maintain consistency with the statutory requirement to install BART
within 5 years, and the source may not be allowed to operate beyond 5
years without BART controls in place. The commenter further stated that
the EPA cannot scrap its existing BART determination for Cholla, which
has been in effect for over 3 years, and issue a new BART determination
that would restart the 5-year BART compliance clock. One commenter
opined that because the EPA's proposal is unlawful, the EPA should
leave the existing BART determination for Cholla in place.
Response 1: The EPA disagrees with the comment that the Cholla SIP
Revision violates the 5-year compliance deadline for BART, the
regulatory requirement to achieve visibility improvement in the first
planning period, or the BART Guidelines. As discussed in our proposed
rule, in the Cholla SIP Revision, ADEQ determined BART to be
LNB+SOFA.\17\ The emission limit associated with installation and
operation of LNB+SOFA while burning coal at Cholla Units 3 and 4 is
0.22 lb/MMBtu. This emission limit is reflected in the Cholla permit
revision that is included as Appendix A of the Cholla SIP Revision. The
permit conditions will become effective and federally enforceable 30
days following publication of this final rule in the Federal Register,
which we anticipate will be prior to the compliance deadline
established in the FIP of December 5, 2017. Therefore, although we
agree with the commenter that BART emission limitations must be in
place within 5 years of approval, we disagree with the commenter that
ADEQ has restarted the 5-year BART compliance clock.
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\17\ See 81 FR 46852 at 46856 (July 19, 2016).
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In addition to its BART determination for Cholla Units 3 and 4,
ADEQ also included a permit revision for Cholla in its SIP submittal.
The permit revision includes the 0.22 lb/MMBtu emission limitation that
would apply until the permanent cessation of coal combustion in Units 3
and 4, and an emission limitation of 0.08 lb/MMBtu that would apply if
the units are converted to natural gas. The commenter appears to have
misconstrued these provisions related to future operation in 2025 to be
part of ADEQ's BART determination. We consider the permit requirements
to cease coal combustion in 2025 and comply with new emission
limitations if Units 3 and 4 are converted to natural gas to be
measures that strengthen the Cholla SIP Revision. The BART
[[Page 15142]]
determination for Units 3 and 4 that we are approving is the 0.22 lb/
MMBtu emission limit. This is consistent with ADEQ's response to a
similar comment, stating: ``Although the new proposal includes
conversion to natural gas-firing at Units 3 and 4 in 2025, ADEQ did not
consider it as a BART control option under the BART determination
process because it is beyond the mandatory five-year window.'' \18\
Furthermore, we note that because Cholla Units 3 and 4 currently cannot
combust natural gas, there is no obligation for ADEQ to determine BART
for those units if they are repowered to operate on natural gas.\19\
Therefore, we consider the 0.08 lb/MMBtu emission limit to be a SIP-
strengthening measure, and approvable as such, but we do not consider
it to be part of the BART determination. In addition, the presence of
an emission limit for future operation on natural gas as a SIP
requirement is not critical to the withdrawal of the FIP. We are not
addressing whether 0.08 lb/MMBtu would be an appropriate BART emission
limit for these units if they were currently combusting natural gas. We
note that because NOX emissions resulting from natural gas
combustion are low, there have been few if any SIPs or FIPs that have
included a determination that BART for electric generating units (EGUs)
combusting natural gas was a lower NOX level than already
being achieved at the source. We are approving the BART determination
in the Cholla SIP Revision in light of the enforceable SIP requirement
for Units 3 and 4 to cease coal combustion in 2025.
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\18\ See Appendix F.6 Responsiveness Summary of the Cholla SIP
Revision (page 6 of 10 in Appendix F.6).
\19\ See SO2 emission limits for San Juan Generating
Station (76 FR 52387, August 22, 2011) and for 6 EGUs in Oklahoma
(76 FR 81727, December 28, 2011), and NOX emission limits
for Jim Bridger and Naughton (79 FR 5031, January 30, 2014), where
emission limits are higher than would be appropriate for BART if the
units were combusting natural gas.
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The Cholla SIP Revision also requires Cholla Units 3 and 4 to
comply with the BART emission limit prior to the end of the first
planning period in 2018. We further note that APS and PacifiCorp have
already installed LNB+SOFA on Cholla Units 3 and 4.\20\ In addition,
the regulatory requirement cited by the commenters, to achieve
visibility improvements in the first planning period, is associated
with alternatives to BART as put forth in 40 CFR 51.308(e)(2). The
Cholla SIP Revision is a re-analysis of BART that is based on new facts
since the promulgation of the FIP; it is not an alternative to BART and
compliance deadlines associated with alternatives to BART are not
relevant to the Cholla SIP Revision.
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\20\ See e.g., page 3 of the Cholla SIP Revision that states the
LNB+SOFA are currently installed on Units 3 and 4.
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We also disagree with the commenter's assertion that a BART
determination that has been in place for over 3 years cannot be revised
when a new material fact has arisen, i.e., that the Cholla units will
not continue to combust coal indefinitely, which had been an assumption
of the original BART determination in the FIP. In the rule proposing to
partially approve and partially disapprove the 2011 RH SIP, the EPA
encouraged the State to submit a revised SIP to replace our FIP, and we
noted that the EPA would work with the State to develop a revised
plan.\21\ We anticipated that ADEQ might develop a SIP to address the
flaws we identified in our review of the 2011 RH SIP. APS and
PacifiCorp also petitioned the Administrator to reconsider certain
aspects of the FIP for Cholla. We granted the petitions based on our
intention to reconsider aspects of the compliance determination
methodology in the FIP. Therefore, although the FIP for Cholla has been
in place for over 3 years, the development of a revised BART analysis
for this facility was not unexpected. As discussed elsewhere in this
final rule, the compliance deadline for the revised BART emission limit
for Cholla remains within the compliance deadline in the FIP of
December 5, 2017. Thus, ADEQ did not extend the BART compliance
deadline in the Cholla SIP Revision beyond the original compliance date
of December 5, 2017.
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\21\ See 77 FR 42834, July 20, 2012.
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Finally, as discussed elsewhere in this final rule, we disagree
with the comment asserting that our action is unlawful. Based on our
evaluation of the Cholla SIP Revision, we have determined that ADEQ
conducted a BART analysis for Cholla that meets the requirements of the
CAA, the RHR, and the BART Guidelines. Therefore, we disagree that the
BART determination promulgated in the FIP should remain in place.
Comment 2: One commenter opined that the EPA's cost analysis for
SNCR was flawed because the EPA based the average cost-effectiveness of
SNCR on 8 years of operation on coal and 12 years of operation on
natural gas. The commenter argued that the operation of SNCR on the
units after the switch to gas in 2025 would result in over 12 years of
additional interest and operation and maintenance costs with minimal
pollution reduction benefits. The commenter asserted that operation of
SNCR for the 8 years of coal combustion and then ceasing to operate
SNCR when the units switch to natural gas would be more cost-effective.
The commenter argued that this would reduce the average cost-
effectiveness of SNCR on Units 3 and 4 to $2,234-$2,342 per ton of
NOX removed and the incremental cost-effectiveness (relative
to LNB/SOFA) to $5,364-$5,458 per ton of NOX removed. The
commenter further argued that its approach (to base the remaining
useful life of SNCR on the time during which the facility would burn
coal) is consistent with how the EPA considered the remaining useful
life for other sources transitioning to gas or other fuels, and cited
to the 2012 BART determinations for the Centralia and Boardman
facilities. The commenter also pointed to the BART determinations for
Healy Unit 1 in Alaska and CENC Unit 5 in Colorado, and reasonable
progress determinations for the Craig Unit 3 in Colorado, where SNCR
was determined to be cost-effective with average cost-effectiveness
values that ranged from $3,526-$4,887 per ton of NOX removed
and incremental cost-effectiveness values that ranged from $5,445-
$9,271 per ton of NOX removed.
Response 2: In reviewing the analysis conducted by ADEQ to assess
whether the Cholla SIP Revision is approvable, the EPA's role is to
decide whether the SIP meets the requirements of the CAA, the RHR, and
the BART Guidelines. In undertaking such a review, the EPA does not
usurp a state's authority but ensures that such authority is reasonably
exercised. The CAA and the RHR set forth five factors that a state must
evaluate to reach a BART determination. However, the CAA and the RHR
provide flexibility to the state in deciding how the factors in the
analysis are weighed.
We note that this comment does not accurately distinguish between
the EPA's cost analysis and the cost analysis by ADEQ. The only cost
analysis that the EPA conducted directly was in support of the 2012 FIP
establishing a BART emission limit for Cholla achievable with the
installation and operation of SCR. The EPA's cost analysis was based on
20 years of operation because, at that time, there was no commitment
from the facility owners that Cholla would cease coal combustion in the
future. Therefore, although the commenter refers to the cost analysis
discussed in the proposed rule as ``the EPA's cost analysis,'' the
comment is actually about ADEQ's cost analysis for SNCR. For purposes
of its BART Reassessment, ADEQ adapted the EPA's cost analysis from
2012 but
[[Page 15143]]
revised the annual cost of controls to account for the planned
cessation of coal combustion in 2025. The commenter is suggesting that
ADEQ should have considered a control scenario that would require SNCR
while combusting coal and would not require SNCR once the units are
repowered to natural gas. The commenter asserts that this SNCR scenario
would be more cost-effective than the operation of SNCR continuously
for 20 years. Based on this consideration of cost-effectiveness, the
commenter asserts that ADEQ should have determined SNCR, applied in
this way, to be BART and that the EPA should not have proposed to
approve the Cholla SIP Revision.
In its response to a similar comment made to ADEQ during the public
comment period for the Cholla SIP Revision, ADEQ argued that it
appropriately calculated the cost-effectiveness of SNCR based on a 20-
year life, with 8 years of operation on coal, and 12 years of operation
on natural gas, because it was reasonable to presume that if SNCR were
required, the units would be required to operate for 20 years or more
to recoup the investment.\22\ The Cholla SIP Revision established as
BART an emission limit of 0.22 lb/MMBtu, achievable with the
installation and operation of LNB+SOFA. Although the units must cease
coal combustion by April 30, 2025, the Cholla SIP Revision provides the
option for those units to be repowered to natural gas with a
NOX emission limit of 0.08 lb/MMBtu and a 20 percent annual
average capacity factor restriction. Emission rates from tangentially-
fired boilers combusting natural gas can be expected to range from an
uncontrolled emission rate of 0.16 lb/MMBtu to a rate of 0.07 lb/MMBtu
when controlled using flue gas recirculation.\23\ Thus, although Units
3 and 4 could continue to operate well beyond 8 years if they are
repowered to natural gas, operation of SNCR would not be required to
meet the 0.08 lb/MMBtu emission limitation in the Cholla SIP Revision.
Therefore, we agree with the commenter that in this case, for Cholla
Units 3 and 4, it is reasonable to evaluate the cost-effectiveness of
SNCR based on the period of time that SNCR would need to be in
operation in order to comply with the applicable emission
limitation.\24\
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\22\ See Appendix F.6 Responsiveness Summary of the Cholla SIP
Revision (p. 8 of 10 in Appendix F.6). The comment submitted to ADEQ
recommended calculating cost-effectiveness of SNCR based on a 7.4-
year life. In this document we generally refer to the period that
Cholla Units 3 and 4 would combust coal as an 8-year period.
\23\ See spreadsheet titled ``Natural gas EF.xlsx'' in the
docket for this rulemaking.
\24\ However, we also note that if ADEQ had evaluated an
emission limit for Units 3 and 4 applicable after the units are
repowered to natural gas, that took into account the continued
operation of SNCR, ADEQ's evaluation of the cost-effectiveness of
SNCR based on 8 years of operation on coal and 12 years of operation
on natural gas would have been more appropriate. We also note that
the commenter cited to rulemakings for two facilities, Centralia and
Boardman, to support the contention that the cost effectiveness of
SNCR on Cholla Units 3 and 4 should have been calculated based on
the period of time the units would be burning coal. Although we
generally agree with the comment, we are not evaluating whether the
facts associated with Centralia and Boardman support this argument.
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However, we further note that the assertion in the comment that
ADEQ erred because it did not evaluate the cost-effectiveness of SNCR
based on an 8-year life is incorrect. In its response to comments on
the Cholla BART Reassessment, ADEQ stated that if it calculated the
cost-effectiveness of SNCR based on a shorter (i.e., 8-year) life the
average cost-effectiveness would be less than $2,500 per ton of
NOX removed and the incremental cost effectiveness would be
less than $5,700 per ton of NOX removed. ADEQ responded that
it would still reject SNCR because the incremental cost-effectiveness
recalculated by the commenter, even at less than $5,700 per ton of
NOX removed, would not be justified based on the slight
incremental visibility improvement. ADEQ evaluated the incremental
visibility improvement of SNCR against LNB+SOFA and found that the
differences in visibility improvement at the various Class I areas
between the two control scenarios were relatively minor in most
cases.\25\ ADEQ noted that the cumulative incremental visibility
improvement of SNCR (as compared to LNB+SOFA) for 13 Class I areas was
1.32 deciviews (ranging from 0.01 to 0.28 deciview at individual Class
I areas), with an average incremental improvement of 0.1 deciview. ADEQ
further noted that the visibility benefits that would be associated
with SNCR on Cholla Units 3 and 4 would last only until 2025 because
the closure or conversion to natural gas would reduce the visibility
benefit of SNCR.\26\ ADEQ concluded that SNCR would not be cost-
effective whether it assumed a useful life of 20 years or 8 years.\27\
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\25\ See Appendix F.6 Responsiveness Summary of the Cholla SIP
Revision (p. 8 of 10 in Appendix F.6).
\26\ Id.
\27\ Id. (page 9 of 10 in Appendix F.6).
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The EPA considered ADEQ's response to the comment and continues to
find that ADEQ's BART Reassessment for Cholla Units 3 and 4, even when
the cost-effectiveness for SNCR is evaluated for an 8-year period, is
consistent with the BART Guidelines and approvable.
The commenter also refers to three facilities, Healy Unit 1,
Colorado Energy Nations Company (CENC) Unit 5, and Craig Unit 3, to
highlight other average and incremental cost-effectiveness values that
have been determined to be reasonable for BART or reasonable progress.
We considered whether these comparisons support a conclusion that ADEQ
was unreasonable in rejecting SNCR based on the average ($2,234 to
$2,342 per ton of NOX removed) and incremental ($5,364 to
$5,458 per ton of NOX removed) cost-effectiveness values
recalculated by the commenter.
The average cost effectiveness values for the three facilities
cited in the comment range from $3,526 to $4,887 per ton of
NOX removed and the incremental cost effectiveness values
range from $5,445 to $9,271 per ton of NOX removed.\28\ The
commenter correctly notes that SNCR was required for these facilities
at average and incremental cost-effectiveness values that exceed both
ADEQ's and the commenter's cost-effectiveness values for SNCR at Cholla
Units 3 and 4. Although the comment did not cite specifically to the
Boardman facility to highlight the cost-effectiveness of SNCR, in that
case the state required, and the EPA approved, a final BART
determination requiring Boardman to meet an emission limit of 0.23 lb/
MMBtu achievable with new LNB and modified overfire air.\29\ The state
rejected SNCR for Boardman, with an average cost effectiveness of
$1,816 per ton of NOX removed, based on the small
incremental visibility improvement of 0.18 deciview at the Mount Hood
Wilderness Area and concerns that excess ammonia from SNCR may result
in increased rates of ammonium sulfate formation.\30\ Thus, although
there are examples of states requiring SNCR at higher average and
incremental cost-effectiveness values, there are also examples of
states rejecting SNCR at even lower cost-effectiveness values than
those recalculated by the commenter for SNCR at Cholla. We further note
that while the state of Colorado determined BART for CENC Unit 5 to be
SNCR (average cost-effectiveness of $4,918 per ton), in the same
action, the state concurrently rejected SNCR for CENC Unit 4 (average
cost effectiveness of $3,729 per ton) and
[[Page 15144]]
determined BART for that unit to be LNB+SOFA.\31\ Therefore, although
we agree with the commenter that states have required SNCR at average
and incremental cost-effectiveness values that are higher than its
recalculated values for SNCR on Cholla Units 3 and 4, there are also
examples of states that have rejected SNCR at average and incremental
cost-effectiveness values that are similar to, or even lower than, the
commenter's recalculated values for SNCR.
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\28\ See Final Rule for Healy Unit 1 (78 FR 10546, February 14,
2013) and final rule for CENC Unit 5 and Craig Unit 3 (77 FR 18052,
March 26, 2012).
\29\ See 76 FR 38997, July 5, 2011.
\30\ See proposed rule, 76 FR 12651 at 12661, March 8, 2011.
\31\ 77 FR 18052, March 26, 2012.
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Furthermore, BART determinations are emission limitations rather
than control technology determinations. For the three units cited by
the commenter, the final BART or reasonable progress emission limits
achievable with SNCR were 0.20 lb/MMBtu for Healy Unit 1, 0.19 lb/MMBtu
for CENC Unit 5, and 0.28 lb/MMBtu for Craig Unit 3.\32\ The BART
emission limitation for Centralia, another facility cited by the
commenter (but for other reasons), was 0.21 lb/MMBtu achievable with
SNCR.\33\ The final BART emission limitation put forth by ADEQ for
Cholla Units 3 and 4, 0.22 lb/MMBtu achievable with LNB+SOFA, is
generally consistent with the emission limits put forth for other
facilities based on SNCR.
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\32\ 78 FR 10546, February 14, 2013 and 77 FR 18052, March 26,
2012.
\33\ 77 FR 72472, December 6, 2012.
---------------------------------------------------------------------------
Although a comparison of cost-effectiveness values from other
facilities is generally a useful exercise to assess the reasonableness
of particular costs, the examples in the comment do not provide
evidence to suggest that ADEQ's weighing of the cost-effectiveness of
SNCR on Cholla Units 3 and 4 was unreasonable. In addition, cost-
effectiveness is not the only factor in determining BART; each BART
determination must be made on a case-by-case basis considering the
relevant facts in each case. The CAA and the RHR provide flexibility to
states in deciding how the five factors are weighed in determining
BART. If the EPA were reassessing BART for Cholla Units 3 and 4 in a
FIP action, the EPA might have weighed the factors differently than
ADEQ and reached a different conclusion. However, the EPA has evaluated
ADEQ's justification for rejecting SNCR based on its consideration of
cost-effectiveness and the visibility improvements from SNCR in
comparison to LNB+SOFA. We consider ADEQ's BART determination for
Cholla Units 3 and 4 to be consistent with the BART Guidelines and a
reasonable use of its discretion in weighing the BART factors.
Comment 3: One commenter argued that the EPA inappropriately relied
on incremental costs and incremental visibility benefits. The commenter
asserted that where a selection of a particular technology as BART is
supported by reasonable total costs, incremental costs should not be
used to override that choice. The commenter further stated that the EPA
only discussed incremental visibility benefits of SNCR relative to LNB
and provided no way to assess the net visibility benefit of installing
SNCR on Units 3 and 4 against the pre-LNB baseline for those units. The
commenter opines that the EPA's lack of analysis of the net visibility
improvements of SNCR is inconsistent with the EPA's prior action for
Cholla.
Response 3: In this action, the EPA is evaluating the analysis
conducted by ADEQ to assess whether the Cholla SIP Revision meets the
requirements of the CAA, the RHR, and the BART Guidelines. We disagree
with the commenter's assertion that it is inappropriate to rely on
incremental costs or incremental visibility benefits. The CAA and the
RHR specify that the states or the EPA must consider cost and
visibility in the five-factor analysis. With respect to the cost
factor, in promulgating the BART Guidelines, the EPA stated, ``In
addition, the guidelines continue to include both average and
incremental costs. We continue to believe that both average and
incremental costs provide information useful for making control
determinations.'' \34\ Section IV.4.e.1 of the BART Guidelines
specifies that states should consider incremental cost-effectiveness in
combination with the average cost-effectiveness. The commenter did not
cite any regulatory language that would preclude incremental cost-
effectiveness in considering the cost of compliance. With respect to
using incremental visibility improvement, we acknowledge that the BART
Guidelines do not explicitly address the issue of considering overall
versus incremental visibility benefits. However, the EPA's response to
comments when promulgating the BART Guidelines stated:
---------------------------------------------------------------------------
\34\ See 70 FR 39104 at 39127, July 6, 2005.
For example, a State can use the CALPUFF model to predict
visibility impacts from an EGU in examining the option to control
NOX and SO2 with SCR technology and a
scrubber, respectively. A comparison of visibility impacts might
then be made with a modeling scenario whereby NOX is
controlled by combustion technology. If expected visibility
improvements are significantly different under one control scenario
than under another, then a State may use that information, along
with information on the other BART factors, to inform its BART
determination.\35\
---------------------------------------------------------------------------
\35\ Id. at 39129.
The EPA's regulations allow states to compare incremental cost-
effectiveness and incremental visibility improvements between different
technologies. The incremental visibility benefit is one way to compare
the visibility improvements from various controls. Other states and the
EPA have considered incremental visibility improvements in many BART
determinations. For this BART determination, ADEQ weighed the small
incremental visibility improvement against the incremental cost-
effectiveness. Based on its weighing of these factors, ADEQ provided a
reasoned justification for selecting LNB+SOFA as BART for Cholla Units
3 and 4, and properly exercised its discretion in its process for
weighing the small visibility improvement against the cost-
effectiveness to reject SCR and SNCR.
Comment 4: One commenter asserted that the EPA's analysis was
flawed because it evaluated BART controls as if there was no existing
BART determination in place for Units 3 and 4. The commenters opined
that the EPA failed to analyze how various pollution controls and other
measures would improve the BART Reassessment by eliminating any
backsliding. The commenter recommended that the EPA evaluate installing
SNCR in the next 18 months to improve the performance of the BART
Reassessment beginning in 2018, and recommended four additional control
strategies to reduce NOX emissions between 2018 and 2025:
(1) Setting an earlier deadline for Units 3 and 4 to shut down or
switch to natural gas, (2) restricting Units 3 and 4 to the lowest
capacity factor necessary between 2018 and 2025, (3) requiring the use
of hybrid NOX reduction measures, e.g., SNCR in combination
with in-duct SCR catalysts, which the commenter said can be installed
at far lower cost and more quickly than conventional SCR, and (4) a
combination of the listed measures with SNCR. The commenter opined that
if this analysis had been done, it would have shown that SNCR and other
measures would significantly improve the BART reassessment by cost-
effectively reducing NOX emissions from Units 3 and 4 prior
to 2025.
Response 4: The EPA's role is to evaluate whether a state
considered the appropriate factors and acted reasonably
[[Page 15145]]
in doing so. In undertaking such a review, the EPA does not usurp a
state's authority but ensures that such authority is reasonably
exercised.
The commenter suggests that the EPA should have evaluated other
NOX control measures that would result in greater emission
reductions from the Cholla SIP Revision and be more comparable to the
emission reductions that would have been achieved under the FIP for
Cholla. As with Comment 2, we note that the commenter has not
accurately described whether it was ADEQ or the EPA that performed (or
would perform) specific analyses. In this action, the EPA is reviewing
the Cholla SIP Revision that was submitted for approval or disapproval.
In that context, the issue is not whether the EPA should or will
undertake the types of analysis recommended by the commenter, but
whether ADEQ's failure to do so means that its BART determination
cannot be approved. We have reviewed ADEQ's BART SIP for Cholla to
determine whether it meets the requirements of the five-factor BART
analysis, as outlined by the CAA, the RHR, and the BART Guidelines.
ADEQ did not put forth a ``better-than-BART'' BART alternative pursuant
to 40 CFR 51.308(e)(2), which would have required a comparison of
emission reductions under BART and the BART alternative.\36\ ADEQ
properly evaluated the new commitments by APS and PacifiCorp related to
future operation of Cholla Units 3 and 4 in determining BART for those
units. For the purposes of its 110(l) analysis, ADEQ compared emissions
of NOX, SO2, and PM10 between its 2011
RH SIP and the Cholla SIP Revision, and also compared emissions of
NOX between the FIP and the Cholla SIP Revision.\37\ ADEQ
appropriately concluded that the differences in emissions were not
inconsistent with CAA section 110(l). Nothing in 110(l) of the CAA,
RHR, or the BART Guidelines requires ADEQ to ensure that the emission
reductions from the Cholla SIP Revision would be numerically equivalent
to the reductions that would have been achieved under the previously
applicable plan (i.e., the FIP). Comments on ADEQ's 110(l) analysis,
and the EPA's responses to those comments, are provided in Section
II.C, below.
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\36\ If ADEQ had done so, there would be a question posed as to
whether it could at the same time re-determine BART in light of the
changed plans for the operation of the Cholla units, or would have
had to use the FIP as the benchmark. We do not address that question
in this action.
\37\ See Tables 5-8 in the Proposed Rule, 81 FR 46852, July 19,
2016.
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The commenter also suggests that the EPA (again, the commenter
mistakenly refers to the EPA rather than ADEQ) should have evaluated
additional operational restrictions on Cholla Units 3 and 4, e.g., an
earlier date for retirement or repowering to natural gas, or capacity
restrictions between 2018 and 2025. Although an earlier retirement date
or capacity restrictions would reduce emissions, in general, states and
the EPA would not impose a retirement or capacity restriction unless it
is requested by the facility operator, because capacity and retirement
are not ``retrofit technolog[ies]'' (the term used in the CAA) or
``system[s] of continuous emissions reductions'' (the term used in the
RHR definition of BART). The BART Guidelines state that potentially
applicable retrofit control alternatives typically prevent the
formation of pollutants (e.g., LNB) or control or reduce emissions of
pollutants after they are formed (e.g., SNCR or SCR), or are a
combination of these processes.\38\ The BART Guidelines go on to say
that ``we do not consider BART as a requirement to redesign the
source,'' or to ``direct States to switch fuel forms, e.g., from coal
to gas.'' \39\ Therefore, consideration of earlier retirement,
repowering, or capacity restrictions that were not put forth by the
facility operator, is not required by the BART Guidelines.
---------------------------------------------------------------------------
\38\ See BART Guidelines at 70 FR 39104 at 39164, July 6, 2005.
\39\ Id.
---------------------------------------------------------------------------
The commenter also suggests that the EPA (again, the commenter
mistakenly refers to the EPA rather than ADEQ) should have evaluated
SNCR with in-duct SCR catalysts, or a combination of SNCR with earlier
retirement, repowering, or capacity restrictions. ADEQ was not required
to consider earlier retirement, repowering, or capacity restrictions to
be consistent with the BART Guidelines, and the combination of SNCR
with those measures does not change our determination. Regarding SNCR
combined with in-duct SCR catalysts, the commenter stated that in-duct
SCR catalysts can be installed at lower cost than conventional SCR.
Although the EPA is aware that the technologies for hybrid SNCR
combined with in-duct SCR systems have been around since the 1990s, we
are not aware of the widespread use of these hybrid systems on
comparably-sized boilers, and the commenter did not provide any
supporting data or information of sufficient specificity to indicate
that this technology should have been considered under BART or that it
would have changed ADEQ's BART determination.\40\ Therefore, we
continue to consider ADEQ's BART determination for Cholla Units 3 and 4
to be consistent with the BART Guidelines, including its evaluation of
LNB+SOFA, SNCR, and SCR.
---------------------------------------------------------------------------
\40\ See, generally, discussion of in-duct SCR catalysts in ``I-
NOXTM Integrated NOX Reduction
Technology-A Lower Capital Cost Solution for NOX
Reduction,'' March 26, 2015, at http://www.mcilvainecompany.com/Decision_Tree/2015%20WEBINARS/March%202015/Stewart%20Bible,%20Fuel%20Tech%20-%20Hot%20Topic%20Hour%203-26-15.pdf.
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Comment 5: One commenter disagreed with the EPA's statement that a
BART reassessment for Cholla is necessary based on new facts that have
arisen since the EPA's final BART determination in 2012. The commenter
further opined that even if new facts could be used to justify
extending the BART compliance deadline, the new facts at issue here
would not be sufficient justification. The commenter also stated that a
business decision by the facility operator to close Unit 2 in advance
of the 2017 BART compliance deadline for that unit should not justify
allowing Units 3 and 4 to delay compliance past 5 years. The commenter
argued that no statutory or regulatory provisions, related guidance, or
prior BART determinations allow, let alone recognize, a utility's
lowest cost option to govern the outcome of a BART determination.
Response 5: We disagree with the assertions in this comment and
generally find that the commenter has misunderstood our proposed action
and the Cholla SIP Revision. The EPA did not state that a BART
reassessment is necessary, but we did indicate that ADEQ has discretion
to reassess BART in light of new information and to seek approval from
the EPA for a SIP revision to replace the FIP. As stated elsewhere in
this final rule, the Cholla SIP Revision does not extend the BART
compliance deadline. It replaces the compliance requirements in the FIP
with different requirements and earlier compliance dates. The 0.22 lb/
MMBtu emission limitation for NOX that ADEQ determined to be
BART will be effective upon the effective date of this final rule and,
therefore, earlier than the FIP's BART deadline of December 5, 2017.
In the Cholla SIP Revision, ADEQ conducted a BART Reassessment
based on the new facts that arose following the EPA's FIP for Cholla.
In 2015, APS and PacifiCorp committed to several operational changes at
Cholla that affect specific factors in the five-factor BART analysis,
namely, the remaining useful
[[Page 15146]]
life of the facility and its corresponding effects on the cost-
effectiveness of controls. Based on the commitments from APS and
PacifiCorp to close Unit 2 by April 1, 2016, continue operation of
Units 3 and 4 with LNB+SOFA and permanently cease coal combustion in
those units by April 30, 2025 with the option to convert to natural gas
combustion by July 31, 2025 at a 20 percent or less average annual
capacity factor, ADEQ conducted a revised BART analysis for Cholla
Units 2, 3, and 4. ADEQ did not rely on the closure of Unit 2 to
justify changes to the BART determination for Units 3 and 4. Rather,
ADEQ reasonably determined that the enforceable closure of Unit 2 prior
to December 5, 2017, satisfies the requirements of the RHR and the CAA
for this unit. ADEQ then conducted a re-analysis of BART for Units 3
and 4 that considered the remaining useful life of potential control
technologies in light of the commitments made by APS and PacifiCorp
related to those units. Based on the changes to the cost effectiveness
of controls, ADEQ reasonably rejected SNCR and SCR as too costly in
comparison to the small additional visibility benefits, and concluded
that the visibility benefits of SNCR or SCR controls after 2025, when
coal combustion ceases and assuming those units are repowered to
natural gas, would be negligible. ADEQ's final BART determination for
Cholla Units 3 and 4 is an emission limitation of 0.22 lb/MMBtu that
will be effective upon the effective date of this final rule.
Therefore, we disagree that our proposal to approve the Cholla SIP
Revision extends any BART compliance deadlines, and we also disagree
with the commenter that the new facts do not warrant a revised
assessment of BART for Cholla.
Although we agree with the commenter that the RHR and BART
Guidelines do not require BART determinations to align with a utility's
lowest-cost option, we also note that this action is not based on the
SIP revision's being the lowest-cost approach. If the FIP were to
remain in place, APS would be free (with respect to CAA requirements)
to cease coal combustion as a way to comply with the SCR-based BART
emission limit, based on its own considerations.\41\ In this case, APS
and PacifiCorp have committed to cease coal combustion in Units 3 and 4
in 2025. Although the motivation for this commitment is irrelevant for
purposes of the RHR, the state has discretion to reassess a BART
determination for Cholla that takes into account the shorter period of
coal combustion because of the potential effect this has on the five
BART factors.
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\41\ See BART Guidelines, 70 FR 39104 at 39171, July 6, 2005.
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Comment 6: One commenter stated that the BART Reassessment will
result in significant public health and environmental benefits,
including very significant near-term and ongoing reductions in climate-
disturbing pollution, toxic mercury, and particulate matter, and that
the complete closure of Unit 2 has already resulted in some near-term
benefits. The commenter described similar multi-pollutant BART
approaches finalized elsewhere in the Southwest. The commenter cited to
the Cholla SIP Revision to provide estimates of emission reductions
from the BART Reassessment compared to the 2011 RH SIP: By 2046, the
BART Reassessment will reduce cumulative SO2 emissions by
about 170,000 tons and cumulative PM10 emissions by 15,000
tons compared to the 2011 RH SIP. In addition, the commenter estimates
that when fully implemented (after 2026), the BART Reassessment will
reduce CO2 emissions by 90 percent from current annual
emissions and reduce mercury emissions from 430 pounds to three pounds
per year.
Response 6: We agree with the commenter that the Cholla SIP
Revision will result in significant near-term and ongoing environmental
benefits. Although the BART Reassessment for Cholla focused on
NOX reductions, emission reductions of other pollutants, as
described by the commenter, also have occurred as a result of the
closure of Unit 2 in 2015 and will occur after the closure or
repowering to natural gas of Units 3 and 4 in 2025. In addition, we
agree with the commenter that similar multi-pollutant approaches have
been taken elsewhere, and we also note that approaches consisting of
interim emission limitations combined with commitments to retire early
or repower to natural gas are common, e.g., a SIP revision (to replace
a FIP) that put forth a revised BART determination for the four units
at the San Juan Generating Station in New Mexico involving closure of
two units by the end of 2017 and an emission limit of 0.23 lb/MMBtu,
achievable with SNCR, on the remaining two units; a SIP revision (to
replace a FIP) that put forth a revised SO2 BART
determination for two units at the Northeastern Power Station in
Oklahoma involving closure of one unit in 2016 and interim emission
limits and capacity restrictions leading to closure of the second unit
by the end of 2026; a SIP revision (to replace a FIP) that put forth a
BART alternative for two units at the Apache Generating Station in
Arizona that involved conversion of one unit to natural gas and SNCR on
the remaining coal-fired unit; as well as the EPA actions on the RH
SIPs for Oregon and Washington approving the BART determinations for
Boardman and Centralia involving interim emission limitations similar
to those imposed on Cholla, and retirements around 2020 or 2025.\42\
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\42\ See 79 FR 60985, October 9, 2014 (final action on revised
BART determination for San Juan in New Mexico); 79 FR 12944, March
7, 2014 (final action on revised BART determination for Northeastern
in Oklahoma); 80 FR 19220, April 10, 2015 (final action on
alternative to BART for Apache in Arizona); 76 FR 38997, July 5,
2011 (final action on BART determination for Boardman in Oregon);
and 77 FR 72742, December 6, 2012 (final action on BART
determination for Centralia in Washington).
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Comment 7: One commenter noted that the BART Reassessment will
result in higher NOX emissions and visibility impacts from
2018 to 2025 and therefore urged the EPA to examine whether those
impacts could be mitigated through a lower continuous emission limit
for SO2 or other measures. The commenter noted that the
current permitted SO2 emission rates at Cholla do not
reflect recent operating levels for SO2.
Response 7: In this action, we are reviewing the Cholla SIP
Revision that was submitted for approval or disapproval. In that
context, the issue is not whether the EPA should examine the types of
mitigation measures recommended by the commenter, but whether ADEQ's
failure to do so means that its BART determination cannot be approved.
The EPA must evaluate whether a state considered the appropriate
factors and acted reasonably in doing so. In undertaking such a review,
the EPA does not usurp a state's authority but ensures that such
authority is reasonably exercised.
The EPA agrees that NOX emissions and visibility impacts
will differ between the Cholla SIP Revision and the provisions of the
FIP that are being withdrawn, and that NOX emissions from
Units 3 and 4 between 2018 and 2025 under the Cholla SIP Revision will
be greater than emissions from those units under the Cholla FIP.
However, after April 30, 2025, when APS and PacifiCorp permanently
cease coal combustion in Units 3 and 4 with the option to convert to
natural gas (at a 20 percent annual average capacity factor), emissions
from the Cholla SIP Revision will be substantially lower than emissions
from those units under the FIP. However, we acknowledge that in
determining whether the BART Reassessment can be approved, we may
[[Page 15147]]
not take into account these greater emission reductions in 2025 and
thereafter.
Although a lower SO2 emission limitation before 2025
would certainly be environmentally beneficial, we note that we have
previously approved the SO2 BART emission limits for
Cholla.\43\ ADEQ's new BART determination was for NOX, and
we must approve it if it meets the requirements of the five-factor BART
analysis, as outlined by the CAA, the RHR, and the BART Guidelines.
ADEQ did not put forth a BART alternative pursuant to 40 CFR
51.308(e)(2), which would have required a comparison of emission
reductions under BART and the BART alternative. ADEQ properly evaluated
the new commitments by APS and PacifiCorp related to future operation
of Cholla Units 3 and 4 in determining BART for those units. For the
purposes of its 110(l) analysis, ADEQ did compare emissions of
NOX, SO2, and PM10 between its 2011 RH
SIP and the Cholla SIP Revision, and compared emissions of
NOX between the FIP and the Cholla SIP Revision.\44\ ADEQ
appropriately concluded that the differences in emissions that it found
would not conflict with CAA section 110(l). Nothing in 110(l) of the
CAA, the RHR, or the BART Guidelines required ADEQ to ensure that the
numerical emission reductions from the Cholla SIP Revision would be
equivalent to the reductions that would have been achieved under the
FIP. Comments and the EPA's responses on ADEQ's 110(l) analysis are
provided elsewhere in Section II.C.
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\43\ See 77 FR 72511 (Dec. 5, 2012). We approved the
SO2 BART emission limits but promulgated FIP provisions
for the compliance testing method because the SIP lacked those
elements.
\44\ See Tables 5-8 in the Proposed Rule, 81 FR 46852, July 19,
2016.
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Comment 8: One commenter noted that although it does not agree with
every reason cited by the EPA in the proposed action, it urges the EPA
to more forward to issue a final approval for the BART Reassessment.
Response 8: We are taking final action in this document to approve
the Cholla SIP Revision and withdraw the provisions of the FIP that
applied to Cholla.
Comment 9: One commenter stated that it supports the EPA's proposed
approval of the BART Reassessment for the following reasons: (1) The
SIP revision includes enforceable emission limits, (2) the EPA's
proposal is based on its own analysis of Arizona's SIP and the five-
factor BART analysis, (3) the EPA appropriately considered Unit 1 as
not BART-eligible, but included Unit 1 in the visibility modeling
because the Cholla SIP Revision also requires that Unit 1 cease burning
coal by April 30, 2025 with the option to repower to natural gas at a
20 percent capacity factor, (4) the BART Reassessment will provide for
greater reasonable progress toward the final goal of natural conditions
earlier than the original FIP, and (5) the EPA's analysis demonstrates
that additional controls would provide only a small visibility
improvement at a cost that is beyond what the EPA has required of any
other BART-eligible EGU.
Response 9: We are taking final action in this document to approve
the Cholla SIP Revision and withdraw the provisions of the FIP that
applied to Cholla. However, we note that the commenter attributed to
the EPA the analyses and conclusion that should actually be attributed
to ADEQ.
B. Comments on Visibility Benefits
Comment 10: One commenter expressed concern that visibility
benefits of installing various levels of NOX control on
Units 3 and 4 were underestimated because the modeling included
emissions from Unit 1 (at the same level in each NOX control
scenario for Units 3 and 4), even though there is no enforceable
commitment to retire Unit 1. The commenter cited to a discussion in the
preamble to the BART Guidelines related to the effect of using existing
conditions versus natural visibility conditions as the baseline for
single source visibility impact determinations. The commenter argued
that the inclusion of Unit 1 in the visibility modeling for Units 3 and
4 resulted in a decrease in the modeled benefit of installing controls
on those units.
Response 10: We agree with the commenter that including Unit 1 in
the modeling reduces the estimate of the visibility benefit of controls
on Units 3 and 4. We also agree that if Unit 1 were part of some source
other than Cholla, it should have been excluded from the modeling.
However, the EPA does not agree that this procedure is incorrect given
the fact that Unit 1 is part of the single source that is Cholla. While
Unit 1 is, in some sense, ``an existing condition'' for purposes of
evaluating the impacts of Units 3 and 4, it is very different than the
``existing conditions'' in the EPA statement cited by the
commenter.\45\ The BART Guidelines describe the ambient conditions to
use in assessing the visibility impact of a source; consistent with the
ultimate goal of the RHR, the visibility impact is assessed relative to
natural conditions. The preamble to the BART Guidelines explains why a
meaningful measure of visibility impacts and potential benefits for a
single source requires the use of pristine natural background rather
than existing conditions, which would reflect the impact of hundreds of
existing sources.\46\ This is not directly relevant to the issue of
whether to include a single additional unit at the source being
evaluated for BART. In practice, for modeling, source impacts are
computed as delta deciviews, which is the difference in deciviews
between the visibility due to the source combined with the natural
background, and the visibility due to the natural background alone. In
other words, all of the visibility impacts modeled with CALPUFF for the
Cholla SIP Revision are relative to natural conditions, for the
baseline and all control scenarios. The commenter seems to imply that
including the emissions from Unit 1 is equivalent to assuming Unit 1 is
part of natural conditions, which is not the case.
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\45\ See BART Guidelines, 70 FR 39104 at 39124, July 6, 2005.
\46\ Ibid. Given the nonlinear way in which visibility
impairment is perceived, the dirtier the background conditions, the
less a source's emissions seem to affect it, ``Using existing
conditions as the baseline . . . would create the following paradox:
The dirtier the existing air, the less likely it would be that any
control is required. . . . Such a reading would render the
visibility provisions meaningless.''
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In modeling for the Cholla SIP Revision, ADEQ had to choose whether
to include the non-BART-eligible Unit 1 emissions that do not vary
across the control scenarios for Units 3 and 4. This choice is not
addressed by the BART Guidelines. Some BART analyses modeled individual
units separately, whereas other BART analyses modeled all units
together. Unit 1 is not part of the natural background, but it is part
of the facility's emissions. The overall BART determination encompasses
an understanding of the visibility impacts, including the particular
procedures followed in modeling them. Several considerations suggest
that including all units in an analysis is a reasonable choice.
Including Unit 1 in the modeling provides a more realistic estimate of
overall visibility impacts for the facility as a whole, and more
realistically accounts for the chemistry that Units 3 and 4 plumes
experience. The Unit 1 emissions may potentially shift the chemistry
and may affect the formation of visibility-affecting particulate matter
from Unit 3 and 4 emissions, for example as the NOX-derived
nitrates in the three plumes compete for available ammonia in
[[Page 15148]]
forming particulate ammonium nitrate. Another consideration, as stated
by the commenter, is that including Unit 1 would tend to make the
estimate of the benefit of controls on Units 3 and 4 smaller when the
delta deciviews (relative to natural visibility conditions) are
compared between control scenarios. This effect is expected to be small
because the effect of including Unit 1 in the modeling would tend to be
cancelled out when computing the benefit of controls. The benefit of
controls is calculated by subtracting the visibility impacts (with
controls applied) from the baseline impact; therefore, the effect of
including Unit 1 in the modeling is captured in both terms. The EPA
also examined this quantitatively by using the change in total
emissions from excluding Unit 1 to scale the modeled estimates of
visibility, and then recalculating the deciview impacts and benefits of
controls. The estimated visibility benefits at Petrified Forest
National Park (the Class I area most affected by emissions from Cholla)
from the use of SCR or SNCR on Units 3 and 4 increased by approximately
5 percent when Unit 1 was excluded.\47\ We would not consider a 5
percent increase in the visibility benefits of SCR or SNCR to justify
disapproving the Cholla SIP Revision. Moreover, the modeled benefits of
LNB+SOFA on Units 3 and 4 would also be higher if Unit 1 were excluded
from the modeling, so the change in the incremental benefit of SCR or
SNCR would be small.
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\47\ See ``vis_impacts'' tab in the spreadsheet titled
``Cholla_pefo_u1_effect.xlsx,'' in the docket for this rulemaking.
---------------------------------------------------------------------------
In summary, although we agree with the comment that inclusion of
Unit 1 in the visibility modeling decreases the modeled visibility
benefits of controls on Units 3 and 4, the effect on the estimated
visibility benefits of controls is small, and the BART Guidelines do
not speak directly to this question. Therefore, the EPA has determined
that ADEQ has reasonably exercised its discretion to include Unit 1 in
its modeling analysis.
Comment 11: One commenter recommended that the EPA consider the net
(not incremental) benefit of installing SNCR on Units 3 and 4. The
commenter noted that even the incremental visibility benefit of SNCR of
0.28 deciview at the Class I area most affected by Cholla (Petrified
Forest National Park) compares well with the net visibility benefits of
other BART determinations made by the EPA in FIPs, which ranged from
0.18-0.32 deciview.
Response 11: As discussed elsewhere in this final rule, with regard
to incremental visibility improvement, the EPA's response to comments
for promulgating the BART Guidelines stated:
For example, a State can use the CALPUFF model to predict
visibility impacts from an EGU in examining the option to control
NOX and SO2 with SCR technology and a
scrubber, respectively. A comparison of visibility impacts might
then be made with a modeling scenario whereby NOX is
controlled by combustion technology. If expected visibility
improvements are significantly different under one control scenario
than under another, then a State may use that information, along
with information on the other BART factors, to inform its BART
determination.\48\
\48\ See 70 FR 39129, July 6, 2005.
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The EPA's regulations allow states to compare incremental
visibility improvements between different technologies. The incremental
visibility benefit is one way to compare the visibility improvements
from various controls. For this BART determination, ADEQ weighed the
small incremental visibility improvement against the incremental cost-
effectiveness, as well as the timing and short duration of this
benefit. Based on its weighing of these factors, ADEQ provided a
reasoned justification for selecting LNB+SOFA as BART for Cholla Units
3 and 4. We have concluded that ADEQ properly exercised its discretion
in its process for weighing the small visibility improvement against
the cost-effectiveness to reject SCR and SNCR.
The commenter notes that even the incremental benefit of SNCR
relative to LNB/SOFA is comparable to benefits seen in previous BART
assessments, at least for the Class I area with the greatest impact.
Visibility is only one of the five factors in a BART assessment, and in
particular must be considered together with the anticipated costs of
controls. As stated previously, the EPA's role is to decide whether the
state's SIP is approvable by evaluating if the Cholla SIP Revision
meets the requirements of the CAA, the RHR, and the BART Guidelines. In
undertaking such a review, the EPA does not usurp a state's authority
but ensures that such authority is reasonably exercised. The CAA and
the RHR provide flexibility to the state in deciding how the factors in
the analysis are weighed. We have concluded that ADEQ properly
exercised its discretion in its process for weighing the small
visibility improvement against the cost-effectiveness to reject SCR and
SNCR.
C. Comments on the CAA Section 110(l) Analysis
Comment 12: One commenter asserted that the EPA's proposal violates
CAA section 110(l) anti-backsliding requirements because it weakens the
existing BART determination for Cholla. The commenter argued that the
BART Reassessment is inconsistent with the EPA's long-standing
interpretation of section 110(l) of the CAA as preventing
implementation plan revisions that would increase overall air pollution
or worsen air quality. The commenter stated that the effect of the BART
Assessment would be to allow Units 3 and 4 to emit an additional 4,161
tons of NOX per year every year between 2018 and 2024, and
would result in worse visibility conditions than the existing BART
determination. The commenter went on to assert that the EPA's
conclusions that the BART Reassessment complies with 110(l) are not
justified because the EPA inappropriately discounted the timing of
pollution reductions and the importance of promptly reducing pollution
and improving visibility. The commenter argued that it is contrary to
the purposes of the regional haze program and 110(l) to trade worse air
quality and increased air pollution in the short term for potential
benefits that may arise years from now. The commenter expressed concern
that the EPA's BART Reassessment, if finalized, would set troubling
precedent for the Coronado Generating Station BART Reassessment put
forth for public comment by ADEQ in July 2016.
The commenter argued that the EPA's proposed approval of the Cholla
SIP Revision is contrary to the requirements of CAA section 110(l). The
commenter cited to case law (identified in our response below) to
support its interpretation that additional air emissions or less
stringent requirements occurring as a result of a SIP revision per se
constitute a violation of CAA section 110(l). Specifically, the
commenter argued that CAA section 110(l) prohibits the EPA from
approving a SIP revision that is less stringent than the FIP it is
replacing, stating, ``This section prohibits states and EPA from
revising an implementation plan if the revision would weaken the
existing plan's requirements.'' The commenter supported its assertion
that the SIP revision weakens the requirements of the existing FIP by
noting that the SIP revision will allow Cholla to emit 4,161 tons per
year more NOX between 2018 and 2025 than would have been
allowed pursuant to the FIP. The commenter characterized the EPA's
proposed
[[Page 15149]]
approval of the SIP revision as relying on two factors for
demonstrating compliance with section 110(l), stating:
According to EPA, the proposal complies with section 110(l)
because (1) there are ``differences in the facts underlying'' the
existing BART determination and the BART ``reassessment,'' and (2)
the BART ``reassessment'' would ``result in greater visibility
improvement than the existing [BART determination] beginning in
2026, which is consistent with the long-term national goal of
restoring natural visibility conditions at Class I areas.'' Neither
justification demonstrates that the BART ``reassessment'' complies
with section 110(l).
Response 12: As discussed in more detail below, the EPA disagrees
with the commenter's legal interpretation that CAA section 110(l) is
violated per se by any SIP revision that allows an increase in actual
air emissions relative to the existing implementation plan. The EPA
also disagrees with the characterization of our proposed section 110(l)
analysis as relying only on the two factors quoted above.
The CAA section 110(l) states in relevant part: ``The Administrator
shall not approve a revision of a plan if the revision would interfere
with any applicable requirement concerning attainment and reasonable
further progress (as defined in section 7501 of this title), and any
other applicable requirement of this chapter.'' This language does not
prohibit every SIP revision that weakens the existing plan's
requirements.\49\ The statutory language of section 110(l) does not
support the commenter's interpretation that additional air emissions or
less stringent requirements occurring as a result of a SIP revision per
se constitutes a violation of CAA section 110(l), and neither does the
case law cited by the commenter.
---------------------------------------------------------------------------
\49\ See, e.g., the EPA's action to approve a revision to the
New Mexico SIP that addressed the BART requirement for
NOX for the San Juan Generating Station in New Mexico, 79
FR 60985 at 60989, October 9, 2014, stating ``Finally, contrary to
the commenter's assertion, CAA section 110(l) does not prohibit a
state from submitting a SIP that is less stringent than a FIP.''
---------------------------------------------------------------------------
The cases cited by the commenter fail to support the commenter's
view. In El Comit[eacute] para el Bienestar de Earlimart v. U.S. EPA,
the Ninth Circuit was addressing a different issue--whether the EPA
reasonably determined the level of emission reductions resulting from a
particular SIP Revision. The court was not considering a SIP revision
that allowed increased emissions.\50\ There, the EPA had consistently
determined that a SIP provision required a 12 percent decrease in
emissions despite the petitioner's contrary interpretation that the
provision required a 20 percent reduction. The court deferred to the
EPA's reasonable interpretation, and concluded ``that the EPA did not
arbitrarily and capriciously fail to consider whether the SIP Revision
violated Sec. 110(l) of the Act, because it reasonably interpreted the
Pesticide Element as committing to a 12 percent reduction in VOC
emissions from 1990 levels by 1999 in the San Joaquin Valley.'' \51\
The case does not support the commenter's interpretation of section
110(l).
---------------------------------------------------------------------------
\50\ See 786 F.3d 688 (9th Cir. 2015).
\51\ Id. at 697 (emphasis in original).
---------------------------------------------------------------------------
The other cases cited by the commenter also fail to support the
commenter's interpretation. In Kentucky Resource Council v. EPA, the
court upheld the EPA's approval of a SIP revision that moved a vehicle
inspection and maintenance program from the SIP to a contingency
measure.\52\ The court examined the EPA's analysis that the SIP
revision would not ``interfere'' with attainment and reasonable further
progress (RFP). As an initial matter, the court rejected an expansive
reading of section 110(l), stating:
---------------------------------------------------------------------------
\52\ 467 F.3d 986 (6th Circuit 2006)
The statute prohibits approval of a revision that ``would
interfere'' with an applicable requirement. Petitioner's reading of
the phrase would substitute ``could'' for ``would.'' On this point
it seems fairly clear that Congress did not intend that the EPA
reject each and every SIP revision that presents some remote
possibility for interference.\53\
---------------------------------------------------------------------------
\53\ Id. at 994.
In Kentucky Resource Council, the SIP substituted other emissions
reductions to make up for the increased emissions from moving the
vehicle inspection and maintenance program to a contingency measure.
The issue was whether the EPA could approve this change without
requiring an attainment demonstration and the court upheld the EPA's
decision that a new attainment demonstration was not required in order
to show that the SIP revision would not interfere pursuant to section
110(l). Thus, the examination of whether the SIP revision would
``worsen air quality'' was based on whether the area--which, unlike
Navajo County, was designated as a nonattainment area for the relevant
NAAQS--would have more difficulty in attaining and maintaining the
NAAQS with the SIP revision--not, as the commenter argues here, whether
the SIP revision would simply result in increased emissions.\54\
---------------------------------------------------------------------------
\54\ The additional case law cited by the commenter, Alabama
Environmental Council v. EPA 711 F.3d 1277 (11th Circuit 2013),
which relied on the same analysis as the Kentucky Resource Council
case, and WildEarth Guardians v. EPA 759 F.3d 1064 (9th Circuit
2014), where the court found that petitioners had not identified any
provision of the SIP revision at issue which weakened pollution
controls, are similarly unavailing.
---------------------------------------------------------------------------
The critical question under section 110(l) is not whether the SIP
revision will cause an increase in actual emissions, it is whether that
increase in actual emissions will interfere with attainment of the
NAAQS or RFP, or if the SIP revision interferes with any other
applicable requirement of the CAA. The fact that actual emissions will
increase means that the EPA's analysis must include an evaluation of
how that emissions increase affects attainment and RFP and other
applicable requirements of the CAA.
The EPA analyzed the requirements of section 110(l) in proposing to
approve the Cholla SIP revision.\55\ The commenter fails to acknowledge
much of the EPA's analysis. The commenter is incorrect that the EPA's
proposal only relied on different facts and greater long term
visibility benefits after 2026 to support approval. Rather, our
proposal considered that fact that Navajo County, where the facility is
located, is attaining the NAAQS for all pollutants.\56\ In addition,
the proposal relied on the fact that the Cholla SIP revision will
result in substantially lower SO2 and PM10
emissions than would have been allowed by the FIP. Finally, for
NOX emissions, the EPA's proposal stated, ``While the Cholla
SIP Revision will require fewer NOX reductions than the FIP
between 2018 and 2025, it will ensure that NOX emissions remain at or
below current levels . . . until 2025 . . .'' (emphasis added).\57\
Based on these facts, the EPA's proposal stated:
---------------------------------------------------------------------------
\55\ 81 FR 46852 at 46862, July 19, 2016.
\56\ Id. at 46862.
\57\ Id. at 46863.
---------------------------------------------------------------------------
Thus, the Arizona SIP does not currently rely on emission
limitations at Cholla to satisfy any attainment or RFP requirements.
Given that the Cholla SIP Revision will result in equivalent or
lower emissions of NOX, PM10 and
SO2 for all future years, compared to current emission
levels, in an area that is designated attainment or has not yet been
designated for all NAAQS, we propose to find that the Cholla SIP
Revision would not interfere with any applicable requirement
concerning attainment or RFP.
The comment letter does not appear to challenge the EPA's analysis
that the SIP revision does not interfere with attainment or RFP for the
reasons discussed above, but rather simply asserts that any increase in
emissions automatically violates section 110(l).\58\
---------------------------------------------------------------------------
\58\ As noted previously, the commenter applies an incorrect
legal standard, insisting that any SIP revision that is less
stringent than the existing SIP or FIP requirement violates section
110(l).
---------------------------------------------------------------------------
[[Page 15150]]
CAA section 110(l) also requires the EPA to evaluate if the SIP
revision will interfere with ``any other applicable requirement of this
chapter.'' The EPA's proposal to approve the Cholla SIP Revision also
carefully analyzed this requirement.\59\ The commenter challenges only
the EPA's proposal to find that the SIP revision complies with the
requirements of the RHR. We disagree with this comment. The commenter
notes that the Cholla SIP Revision is predicted to result in higher
visibility impairment at Petrified Forest National Park than the FIP
from 2018 to 2025. We agree. As discussed in our proposed rule, in its
section 110(l) analysis, ADEQ stated that the Cholla SIP Revision would
result in less visibility improvement between 2018 and 2025, but would
result in greater improvements starting in 2026.\60\ This does not,
however, support the argument that the SIP will interfere with the
requirements of the visibility program. As discussed above, we have
determined that the Cholla SIP Revision meets the BART requirements. We
also proposed that the Cholla SIP Revision would not interfere with the
RHR because the achievement of greater visibility improvement from the
Cholla SIP Revision beginning in 2026 would be consistent with the
long-term national goal of the RHR of restoring visibility conditions
at Class I areas.\61\ We further noted that while the Cholla SIP
Revision would require fewer NOX reductions than the FIP
between 2018 and 2025, it would ensure that NOX emission
remain at or below current levels until 2025, after which time it would
require a substantial reduction in NOX emissions compared to
both current levels and the FIP.\62\
---------------------------------------------------------------------------
\59\ 81 FR 46852 at 46862, July 19, 2016.
\60\ Id. at 46859.
\61\ Id. at 46862.
\62\ Id.
---------------------------------------------------------------------------
The commenter challenges our proposed finding that the SIP revision
meets the requirements for BART. Our proposal concluded that the Cholla
SIP Revision is consistent with BART, and therefore does not interfere
with an applicable requirement of the CAA and the RHR.\63\ For the
reasons discussed in responses to other comments, ADEQ conducted an
adequate BART analysis for Cholla. ADEQ considered the appropriate
factors and reached a reasonable conclusion. Our analysis that the
Cholla SIP Revision is approvable pursuant to CAA section 110(l)
considered compliance with BART and also considered that ``the Cholla
SIP Revision would result in greater visibility improvement than the
existing SIP and FIP requirements beginning in 2026, which is
consistent with the long-term national goal of restoring natural
visibility conditions at Class I areas.'' \64\ The commenter contends
that the EPA was justifying ``weakening'' the Arizona SIP and allowing
``backsliding'' based on new or different facts. That is not the case.
The EPA was evaluating whether the SIP revision complied with the
requirements for BART, which it does. The proposal then stated:
---------------------------------------------------------------------------
\63\ Id.
\64\ Id.
Furthermore, the Cholla SIP Revision would result in greater
visibility improvement than the existing SIP and FIP requirements
beginning in 2026, which is consistent with the long term national
---------------------------------------------------------------------------
goal of restoring natural visibility conditions at Class I areas.
The commenter construes this statement incorrectly, asserting that
this statement means the EPA is justifying compliance with section
110(l) by crediting later emission reductions to offset earlier
emission increases. As noted earlier, section 110(l) does not prohibit
approving a SIP revision that allows an increase in actual emissions
provided it does not interfere with attainment of the NAAQS, RFP, or
any other applicable requirement. All of those criteria have been met
for the reasons discussed above. The EPA, however, noted that the
substantial emissions reductions from the Cholla SIP Revision--both
those occurring from the shutdown of Unit 2 in 2016 and additional
NOX reductions in 2025--will support efforts to meet the RHR
goal of reaching natural visibility in 2064.
For the reasons discussed above, the EPA disagrees with the
commenter that our approval of the Cholla SIP revision is inconsistent
with CAA section 110(l).
D. Other Comments
Comment 13: One commenter argued that the EPA's proposal negates
the 2018 reasonable progress goals (RPGs) for Arizona. The EPA set 2018
RPGs for Arizona in its Final Phase 3 Rule that relied upon the
emission reductions required by its regional haze FIP for Arizona. The
commenter asserted that in delaying Cholla's compliance with its BART
obligations past 2017, the BART Reassessment necessitates the
development of entirely new 2018 RPGs.
Response 13: The EPA disagrees with the comment that the Cholla SIP
Revision negates or otherwise adversely effects the 2018 RPGs for
Arizona. The 2018 RPGs account for emission reductions expected to
occur by the end of the first planning period. The compliance date for
the NOX emission reductions, achievable with SCR, required
in the FIP for Cholla was December 5, 2017. As noted in our proposed
rule, the anticipated NOX reductions in 2018 from Units 3
and 4 associated with the FIP would have been 4,763 tons more than the
reductions from those units under the Cholla SIP Revision for that
year. However, cumulative NOX reductions in 2016 and 2017,
from the Cholla SIP Revision, would be 6,302 tons greater than the FIP
for Cholla as a result of the closure of Unit 2.\65\ In addition, the
closure of Unit 2 required in the Cholla SIP Revision also results in
additional reductions in SO2 and PM10 in 2016 and
2017.\66\ Because the NOX, SO2, and
PM10 reductions from the Cholla SIP Revision are greater
than the reductions that would have occurred under the FIP in 2016,
2017, and 2018, and because the 2018 RPGs consider emission reductions
that occur until the end of 2018, the Cholla SIP Revision aids, rather
than negates, the 2018 RPGs.
---------------------------------------------------------------------------
\65\ See Table 8 in our proposed rule at 81 FR 46852, 46858
(July 19, 2016). We further note that the emission reductions in
Table 8 associated with Unit 2 are based on the operation of Unit 2
until April 1, 2016. Because Unit 2 closed in 2015, the actual
emission reductions from Unit 2 in 2016 would be lower than
estimated in our proposed rule.
\66\ Id. Tables 6 and 7.
---------------------------------------------------------------------------
As discussed elsewhere in this final rule, we disagree with the
commenter's characterization that the Cholla SIP Revision is delaying
the compliance deadline for BART beyond December 5, 2017. We are
approving ADEQ's determination for Cholla Units 3 and 4 that BART is
the use of LNB+SOFA. The emission limitations associated with this BART
determination will become effective on April 26, 2017.
Finally, although the Cholla SIP Revision will result in greater
NOX emissions than the FIP from Cholla Units 3 and 4 between
December 5, 2017 and April 30, 2025, the requirements in the Cholla SIP
Revision to permanently retire Unit 2 by April 1, 2016, combined with
the permanent cessation of coal combustion in Units 1, 3, and 4 by
April 30, 2025 and the potential conversion of those units to natural
gas by July 31, 2025, will aid Arizona's RPGs more than we had
originally attributed to the FIP provisions we are withdrawing in this
action.
Comment 14: One commenter noted that if the EPA takes final action
to approve the BART Reassessment and
[[Page 15151]]
withdraw the FIP for Cholla, a provision in 40 CFR 52.145(f)(5)(i)(A)
that requires continuous emission monitoring systems (CEMS) for
SO2 at Cholla Units 2, 3, and 4 to be in full compliance
with the requirements in 40 CFR part 75, will be duplicative because
that requirement is already contained in the Cholla SIP Revision. The
commenter requests that the EPA remove Cholla completely from the final
version of the regulatory text that will be codified at 40 CFR 52.145.
Response 14: The EPA agrees with the comment that the Arizona RH
FIP provisions should not contain any provisions related to Cholla
after the EPA takes final action to withdraw the provisions in 40 CFR
52.145 that are applicable to this facility. As stated in our proposed
rule, ``we propose to withdraw the provisions of the Arizona Regional
Haze FIP that apply to Cholla;'' the retention of the reference to
Cholla in 40 CFR 52.145(f)(5)(i)(A) was inadvertent.\67\ We also agree
with the commenter that the condition is duplicative to the requirement
already contained in the Cholla permit revision that was submitted as
part of the Cholla SIP Revision. Therefore, in this final action, we
are removing from 40 CFR 52.145(f)(5)(i)(A) the sentence that reads:
``In addition, the owner/operator of Cholla Units 2, 3, and 4 shall
calibrate, maintain, and operate a CEMS, in full compliance with the
requirements found in 40 CFR part 75, to accurately measure
SO2 emissions and diluent at the inlet of the sulfur dioxide
control device.'' The remaining provisions in 40 CFR 52.145(f)(5)(i)(A)
will continue to exist and apply to the Coronado Generating Station.
---------------------------------------------------------------------------
\67\ See 81 FR 46852 at 46863, July 19, 2016.
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III. Summary of Final Action
For the reasons described above, the EPA is taking final action to
approve the Cholla SIP Revision. Because this approval fills the gap in
the Arizona RH SIP that was left by the EPA's prior partial disapproval
with respect to Cholla, we are also taking final action to withdraw the
provisions of the FIP that applied to Cholla. This final action also
constitutes our action on the petitions for reconsideration submitted
by APS and PacifiCorp on the FIP.
IV. Environmental Justice Considerations
As shown in Tables 6 and 7 of the proposed rule, the Cholla SIP
Revision will result in lower emissions of both PM10 and
SO2 compared to the emissions we had previously projected
under the existing requirements beginning in 2016, with greater
emission reductions from the Cholla SIP Revision occurring over time
(i.e., in the periods 2017-2025, and 2026 and thereafter).\68\ As shown
in Table 8 of the proposed rule, the Cholla SIP Revision will result in
greater NOX emissions than the FIP between 2018 and 2025,
but will achieve substantially lower NOX emissions than the
FIP in 2016, 2017, and 2026 and thereafter.\69\ In addition, as noted
in our proposed rule, Cholla is located in Navajo County, Arizona,
which is currently designated as attainment or unclassifiable for the
following NAAQS: Carbon monoxide, lead, nitrogen dioxide, ozone (2008
NAAQS), PM2.5 (1997 and 2006 NAAQS), PM10, and
SO2 (1971 NAAQS). ADEQ also noted in its submittal that it
has recommended a designation of attainment/unclassifiable for this
area for the 2012 PM2.5 and 2010 SO2 standards.
Therefore, this final action will not have potential disproportionately
high and adverse human health or environmental effects on minority,
low-income, or indigenous populations.
---------------------------------------------------------------------------
\68\ See 81 FR 46852 at 46857-46858, July 18, 2016.
\69\ Id. at 46858-46859.
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V. Incorporation by Reference
In this rule, the EPA is finalizing regulatory text that includes
incorporation by reference. In accordance with the requirements of 1
CFR 51.5, the EPA is finalizing the incorporation by reference
``Significant Permit Revision No. 61713 to Operating Permit No. 53399''
issued by ADEQ on October 16, 2015. Therefore, these materials have
been approved by the EPA for inclusion in the SIP, have been
incorporated by reference by the EPA into that plan, are fully
federally enforceable under sections 110 and 113 of the CAA as of the
effective date of this final rule, and will be incorporated by
reference by the Director of the Federal Register in the next update to
the SIP compilation.\70\ The EPA has made, and will continue to make,
this document available electronically through www.regulations.gov and
in hard copy at the EPA Region IX Office. Please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section of this
preamble for more information.
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\70\ 62 FR 27968, May 22, 1997.
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VI. Statutory and Executive Order Reviews
Additional information about these statutes and Executive Orders
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review. This rule applies to only one facility and is therefore not
a rule of general applicability.
B. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the provisions of the PRA. Burden is defined at 5 CFR 1320.3(b).
C. Regulatory Flexibility Act (RFA)
I certify that this final action will not have a significant
economic impact on a substantial number of small entities. This action
will not impose any requirements on small entities. Firms primarily
engaged in the generation, transmission, and/or distribution of
electric energy for sale are small if, including affiliates, the total
electric output for the preceding fiscal year did not exceed 4 million
megawatt hours. The two owners of Cholla, APS and PacifiCorp, exceed
this threshold.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action does not impose additional requirements
beyond those imposed by state law. Accordingly, no additional costs to
State, local, or tribal governments, or to the private sector, will
result from this action.
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 on the distribution of power
and responsibilities among the various levels of government.
F. Executive Order 13175: Coordination With Indian Tribal Governments
This action does not have tribal implications, as specified in
Executive Order 13175, because the SIP is not approved to apply on any
Indian reservation land or in any other area where the EPA or an Indian
tribe has demonstrated that a tribe has jurisdiction, and will not
impose substantial direct costs on tribal governments or preempt tribal
law.
[[Page 15152]]
Thus, Executive Order 13175 does not apply to this action.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because it does not impose additional
requirements beyond those imposed by state law.
H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.
I. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Population
The EPA believes the human health or environmental risk addressed
by this action will not have potentially disproportionately high and
adverse human health or environmental effects on minority, low-income
or indigenous populations. Although this final action to approve the
Cholla SIP Revision will result in greater NOX emissions
than we had previously projected to occur under the FIP it replaces
over the 2018-2025 period, emissions of PM10 and
SO2 will be lower under the Cholla SIP Revision beginning in
2016, with greater emission reductions from the Cholla SIP Revision
occurring over time (i.e., in the periods 2017-2025, and 2026 and
thereafter). In addition, the Cholla SIP Revision will result in
greater NOX reductions than the FIP in 2016, 2017, and 2026
and thereafter. In addition, as noted in our proposed rule, Cholla is
located in Navajo County, Arizona, which is currently designated as
attainment or unclassifiable for the following NAAQS: Carbon monoxide,
lead, nitrogen dioxide, ozone (2008 NAAQS), PM2.5 (1997 and
2006 NAAQS), PM10, and SO2 (1971 NAAQS). ADEQ
also noted in its submittal that it has recommended a designation of
attainment/unclassifiable for this area for the 2012 PM2.5
and 2010 SO2 standards. Therefore, this final action will
not have disproportionately high and adverse human health or
environmental effects on minority or low-income populations.
K. Congressional Review Act (CRA)
This rule is exempt from the CRA because it is a rule of particular
applicably. EPA is not required to submit a rule report regarding this
action under section 801 because this is a rule of particular
applicability that only applies to a single named facility.
L. Petitions for Judicial Review
Under section 307(b)(1) of the Clean Air Act, petitions for
judicial review of this action must be filed in the United States Court
of Appeals for the appropriate circuit by May 26, 2017. Filing a
petition for reconsideration by the Administrator of this final rule
does not affect the finality of this rule for the purposes of judicial
review nor does it extend the time within which a petition for judicial
review may be filed, and shall not postpone the effectiveness of such
rule or action. This action may not be challenged later in proceedings
to enforce its requirements (see section 307(b)(2)).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Reporting and recordkeeping requirements, Sulfur dioxide,
Visibility.
Dated: March 16, 2017.
E. Scott Pruitt,
Administrator.
Part 52, chapter I, title 40 of the Code of Federal Regulations is
amended as follows:
PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
0
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
Subpart D--Arizona
0
2. Section 52.120 is amended by:
0
a. Adding in paragraph (d), under the table heading ``EPA-Approved
Source-Specific Requirements'' an entry for ``Cholla Power Plant''
after the entry for ``Arizona Electric Power Cooperative's Apache
Generating Station.''
0
b. Adding in paragraph (e), under the table heading ``Table 1--EPA-
Approved Non-Regulatory and Quasi-Regulatory Measures'' after the entry
for ``Arizona Lead SIP Revision'', an entry for ``Arizona State
Implementation Plan Revision to the Arizona Regional Haze Plan for
Arizona Public Service Cholla Generating Station.''
The additions read as follows:
Sec. 52.120 Identification of plan.
* * * * *
(d) * * *
EPA-Approved Source-Specific Requirements
----------------------------------------------------------------------------------------------------------------
EPA approval
Name of source Order/permit No. Effective date date Explanation
----------------------------------------------------------------------------------------------------------------
Arizona Department of Environmental Quality
----------------------------------------------------------------------------------------------------------------
* * * * * * *
Cholla Power Plant........... Significant October 16, 2015........ 3/27/2017, Permit issued by
Permit Revision [INSERT Arizona Department
No. 61713 to Federal of Environmental
Operating Register Quality. Submitted
Permit No. CITATION]. on October 22,
53399. 2015.
* * * * * * *
----------------------------------------------------------------------------------------------------------------
(e) * * *
[[Page 15153]]
Table 1--EPA-Approved Non-Regulatory and Quasi-Regulatory Measures
[Excluding certain resolutions and statutes, which are listed in tables 2 and 3, respectively] \1\
----------------------------------------------------------------------------------------------------------------
Applicable
geographic or
Name of SIP provision nonattainment State submittal EPA approval date Explanation
area or title/ date
subject
----------------------------------------------------------------------------------------------------------------
The State of Arizona Air Pollution Control Implementation Plan
Clean Air Act Section 110(a)(2) State Implementation Plan Elements (Excluding Part D Elements and Plans)
----------------------------------------------------------------------------------------------------------------
* * * * * * *
Arizona State Implementation Source-Specific.. October 22, 2015. 3/27/2017, Revised source-
Plan Revision to the Arizona [INSERT Federal specific BART limits
Regional Haze Plan for Arizona Register for NOX for Cholla
Public Service Cholla CITATION]. Power Plant adopted
Generating Station. October 22, 2015.
* * * * * * *
----------------------------------------------------------------------------------------------------------------
\1\ Table 1 is divided into three parts: Clean Air Act Section 110(a)(2) State Implementation Plan Elements
(excluding Part D Elements and Plans), Part D Elements and Plans (other than for the Metropolitan Phoenix or
Tucson Areas), and Part D Elements and Plans for the Metropolitan Phoenix and Tucson Areas.
* * * * *
0
3. Section 52.145 is amended by revising paragraphs (f)(1) through (5)
and (10) to read as follows:
Sec. 52.145 Visibility protection.
* * * * *
(f) * * *
(1) Applicability. This paragraph (f) applies to each owner/
operator of the following coal-fired electricity generating units
(EGUs) in the state of Arizona: Coronado Generating Station, Units 1
and 2. The provisions of this paragraph (f) are severable, and if any
provision of this paragraph (f), or the application of any provision of
this paragraph (f) 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 (f), shall not
be affected thereby.
(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. For purposes of this paragraph (f): ADEQ means the
Arizona Department of Environmental Quality.
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 unit.
Coal-fired unit means any of the EGUs identified in paragraph
(f)(1) of this section.
Continuous emission monitoring system or CEMS means the equipment
required by 40 CFR part 75 and this paragraph (f).
Emissions limitation or emissions limit means any of the Federal
Emission Limitations required by this paragraph (f) or any of the
applicable PM10 and SO2 emissions limits for
Coronado Generating Station submitted to EPA as part of the Arizona
Regional Haze SIP in a letter dated February 28, 2011, and approved
into the Arizona State Implementation Plan on December 5, 2012.
Flue Gas Desulfurization System or FGD means a pollution control
device that employs flue gas desulfurization technology, including an
absorber utilizing lime, fly ash, or limestone slurry, for the
reduction of sulfur dioxide emissions.
Group of coal-fired units means Units 1 and 2 for Coronado
Generating Station.
lb means pound(s).
MMBtu means million British thermal unit(s).
NOX means nitrogen oxides expressed as nitrogen dioxide
(NO2).
Owner(s)/operator(s) means any person(s) who own(s) or who
operate(s), control(s), or supervise(s) one or more of the units
identified in paragraph (f)(1) of this section.
Operating hour means any hour that fossil fuel is fired in the
unit.
PM10 means filterable total particulate matter less than 10 microns
and the condensable material in the impingers as measured by Methods
201A and 202 in 40 CFR part 51, appendix M. Regional Administrator
means the Regional Administrator of EPA Region IX or his/her authorized
representative.
SO2 means sulfur dioxide.
SO2 removal efficiency means the quantity of SO2 removed
as calculated by the procedure in paragraph (f)(5)(iii)(B) of this
section.
Unit means any of the EGUs identified in paragraph (f)(1) of this
section.
Valid data means data recorded when the CEMS is not out-of-control
as defined by 40 CFR part 75.
(3) Federal emission limitations--(i) NOX emission limitations. The
owner/operator of each coal-fired unit subject to this paragraph (f)
shall not emit or cause to be emitted NOX in excess of the
following limitations, in pounds per million British thermal units (lb/
MMBtu) from any coal-fired unit or group of coal-fired units. Each
emission limit shall be based on a rolling 30-boiler-operating-day
average, unless otherwise indicated in specific paragraph.
------------------------------------------------------------------------
Federal
Coal fired unit or group of coal-fired units emission
limitation
------------------------------------------------------------------------
Coronado Generating Station Unit 1...................... 0.065
Coronado Generating Station Unit 2...................... 0.080
------------------------------------------------------------------------
(ii) [Reserved]
(4) Compliance dates. (i) The owners/operators of each unit subject
to this paragraph (f) shall comply with the NOX emissions
limitations and other NOX-related requirements of this
paragraph (f) no later than December 5, 2017.
(ii) The owners/operators of each unit subject to this paragraph
(f) shall comply with the applicable PM10 and SO2
emissions limits submitted to EPA as part of the Arizona Regional Haze
SIP in a letter dated February 28, 2011, and approved into the Arizona
State Implementation Plan on December 5, 2012, as well as the related
compliance, recordkeeping and reporting of this paragraph (f) no later
than June 3, 2013.
(5) Compliance determinations for NOX and SO2--(i) Continuous
emission monitoring system. (A) At all times after the compliance date
specified in paragraph (f)(4) of this section, the owner/operator of
each coal-fired unit shall maintain, calibrate, and operate a CEMS, in
full compliance with the requirements found at 40 CFR part 75, to
accurately measure SO2, NOX, diluent, and stack
gas volumetric flow rate from each unit. All valid CEMS hourly data
shall be used to determine compliance with the emission limitations for
NOX and SO2 in paragraph (f)(3) of this section
for each unit. When the CEMS is out-of-control
[[Page 15154]]
as defined by 40 CFR part 75, that CEMS data shall be treated as
missing data, and not used to calculate the emission average. Each
required CEMS must obtain valid data for at least 90 percent of the
unit operating hours, on an annual basis.
(B) 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 40 CFR part 75 requirements, relative accuracy test audits shall
be calculated for both the NOX and SO2 pounds per
hour measurement and the heat input measurement. The CEMS monitoring
data shall not be bias adjusted. The inlet SO2 and diluent
monitors required by this rule shall also meet the Quality Assurance/
Quality Control (QA/QC) requirements of 40 CFR part 75. The testing and
evaluation of the inlet monitors and the calculations of relative
accuracy for lb/hr of NOX, SO2 and heat input
shall be performed each time the 40 CFR part 75 CEMS undergo relative
accuracy testing.
(ii) Compliance determinations for NOX. (A) [Reserved]
(B) Coronado Generating Station. Compliance with the NOX
emission limits for Coronado Unit 1 and Coronado Unit 2 in paragraph
(f)(3)(i) of this section shall be determined on a rolling 30 boiler-
operating-day basis. The 30-boiler-operating-day rolling NOX
emission rate for each unit shall be calculated in accordance with the
following procedure: Step one, 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; Step two, 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;
Step three, divide the total number of pounds of NOX emitted
from that unit during the thirty (30) boiler operating days by the
total heat input to the unit during the thirty (30) boiler operating
days. A new 30-boiler-operating-day rolling average NOX
emission rate shall be calculated for each new boiler operating day.
Each 30-boiler-operating-day average NOX emission rate shall
include all emissions that occur during all periods within any boiler
operating day, including emissions from startup, shutdown, and
malfunction.
(C) 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 of the 30-day
rolling average.
(iii) Compliance determinations for SO2. (A) The 30-day rolling
average SO2 emission rate for each coal-fired unit shall be
calculated in accordance with the following procedure: Step one, sum
the total pounds of SO2 emitted from the unit during the
current boiler-operating day and the previous twenty-nine (29) boiler-
operating days; step two, sum the total heat input to the unit in MMBtu
during the current boiler- operating day and the previous twenty-nine
(29) boiler-operating day; and step three, divide the total number of
pounds of SO2 emitted during the thirty (30) boiler-
operating days by the total heat input during the thirty (30) boiler-
operating days. A new 30-day rolling average SO2 emission
rate shall be calculated for each new boiler-operating day. Each 30-day
rolling average SO2 emission rate shall include all
emissions and all heat input that occur during all periods within any
boiler-operating day, including emissions from startup, shutdown, and
malfunction.
(B) [Reserved]
(C) If a valid SO2 pounds per hour at the outlet of the
FGD system or heat input is not available for any hour for a unit, that
heat input and SO2 pounds per hour shall not be used in the
calculation of the 30-day rolling average.
(D) If both a valid inlet and outlet SO2 lb/MMBtu and an
outlet value of lb/hr of SO2 are not available for any hour,
that hour shall not be included in the efficiency calculation.
* * * * *
(10) Equipment operations. (i) [Reserved]
(ii) Coronado Generating Station. At all times, including periods
of startup, shutdown, and malfunction, the owner or operator of
Coronado Generating Station Unit 1 and Unit 2 shall, to the extent
practicable, maintain and operate each unit in a manner consistent with
good air pollution control practices for minimizing emissions. The
owner or operator shall continuously operate pollution control
equipment at all times the unit it serves is in operation, and operate
pollution control equipment in a manner consistent with technological
limitations, manufacturer's specifications, and good engineering and
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 which may include, but is not limited to,
monitoring results, review of operating and maintenance procedures, and
inspection of each unit.
* * * * *
[FR Doc. 2017-05724 Filed 3-24-17; 8:45 am]
BILLING CODE 6560-50-P