Rule2025-14850
Air Plan Approval; IA; Regional Haze State Implementation Plan for the Second Implementation Period
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
August 5, 2025
Effective
September 4, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is taking final action to approve the Regional Haze State Implementation Plan (SIP) for the State of Iowa as satisfying applicable requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule (RHR) for the program's second implementation period. Iowa's SIP submission addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to the CAA.
Full Text
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<title>Federal Register, Volume 90 Issue 148 (Tuesday, August 5, 2025)</title>
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[Federal Register Volume 90, Number 148 (Tuesday, August 5, 2025)]
[Rules and Regulations]
[Pages 37389-37403]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-14850]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R07-OAR-2024-0313; FRL-12096-02-R7]
Air Plan Approval; IA; Regional Haze State Implementation Plan
for the Second Implementation Period
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is taking final
action to approve the Regional Haze State Implementation Plan (SIP) for
the State of Iowa as satisfying applicable requirements under the Clean
Air Act (CAA) and EPA's Regional Haze Rule (RHR) for the program's
second implementation period. Iowa's SIP submission addresses the
requirement that states must periodically revise their long-term
strategies for making reasonable progress towards the national goal of
preventing any future, and remedying any existing, anthropogenic
impairment of visibility, including regional haze, in mandatory Class I
Federal areas. The SIP submission also addresses other applicable
requirements for the second implementation period of the regional haze
program. The EPA is taking this action pursuant to the CAA.
DATES: This final rule is effective on September 4, 2025.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-R07-OAR-2024-0313. All documents in the docket are
listed on the <a href="https://www.regulations.gov">https://www.regulations.gov</a> website. Although listed in
the index, some information is not publicly available, i.e.,
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Certain other material, such as
copyrighted material, is not placed on the internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available through <a href="https://www.regulations.gov">https://www.regulations.gov</a> or please
contact the person identified in the FOR FURTHER INFORMATION CONTACT
section for additional information.
[[Page 37390]]
FOR FURTHER INFORMATION CONTACT: Bethany Olson, U.S. Environmental
Protection Agency, Region 7 Office, Air Permitting and Planning Branch,
11201 Renner Boulevard, Lenexa, Kansas 66219; telephone number: (913)
551-7905; email address: <a href="/cdn-cgi/l/email-protection#254a49564a4b0b4740514d444b5c654055440b424a53"><span class="__cf_email__" data-cfemail="d2bdbea1bdbcfcb0b7a6bab3bcab92b7a2b3fcb5bda4">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document ``we,'' ``us,'' and
``our'' refer to EPA.
Table of Contents
I. What is being addressed in this document?
II. Background
III. EPA's Response to Comments
IV. What action is EPA taking?
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews
I. What is being addressed in this document?
The EPA is approving Iowa's Regional Haze plan for the second
planning period and adding three Iowa source-specific permits into the
Iowa SIP submitted on August 15, 2023. The Iowa Department of Natural
Resources (IDNR) submitted the plan to satisfy the regional haze
program requirements pursuant to CAA sections 169A and 169B and 40 Code
of Federal Regulations (CFR) 51.308. As required by section 169A of the
CAA, the federal RHR calls for state and federal agencies to work
together to improve visibility in 156 national parks and wilderness
areas. The rule requires the states, in coordination with the EPA, the
National Parks Service (NPS), the U.S. Fish and Wildlife Service (FWS),
the U.S. Forest Service (USFS), and other interested parties, to
develop and implement air quality protection plans to reduce the
pollution that causes visibility impairment. Visibility impairing
pollutants include fine and coarse particulate matter (PM) (e.g.,
sulfates, nitrates, organic carbon, elemental carbon, and soil dust)
and their precursors (e.g., sulfur dioxide (SO<INF>2</INF>), nitrogen
oxides (NO<INF>X</INF>), and, in some cases, volatile organic compounds
(VOC) and ammonia (NH<INF>3</INF>)). As discussed in further detail in
our Notice of Proposed Rulemaking (NPRM) the EPA finds that Iowa has
submitted a Regional Haze plan that meets the Regional Haze
requirements for the second planning period. The State's submission and
NPRM can be found in the docket for this action.
II. Background
On August 15, 2023, IDNR submitted a revision to the Iowa SIP to
address its regional haze obligations for the second implementation
period, which runs through 2028. The long-term strategy for Iowa's
Regional Haze plan includes emission limits contained in three air
construction permits issued to three sources owned by MidAmerican
Energy Company (MidAmerican) and submitted by Iowa for incorporation
into the SIP in 40 CFR 52.820(d) EPA approved state source-specific
requirements. Louisa Generating Station (LGS) permit #05-A-031-P6
contains a SO<INF>2</INF> emission limit of 800 lb/hr based on a 30-day
rolling average for the main boiler. Walter Scott Jr. Energy Center
unit 3 (WSEC-3) permit #75-A-357-P9 contains a SO<INF>2</INF> emission
limit of 770 lb/hr based on a 30-day rolling average. Walter Scott Jr.
Energy Center unit 4 (WSEC-4) permit #03-A-425-P4 contains a
SO<INF>2</INF> emission limit of 0.1 lb/MMBtu and a NO<INF>X</INF>
emission limit of 0.07 lb/MMBtu. The state's SIP submission requested
that the EPA not act on Condition 11 of the permits for LGS and WSEC-3
nor Condition 6 of the permit for WSEC-4, and accordingly those
conditions are not included in this action. The full permits are
included in appendix E of the state submission in the docket for this
action.
The State's submission met the public notice requirements in
accordance with 40 CFR 51.102. The submission also satisfied the
completeness criteria of 40 CFR part 51, appendix V. Iowa made its 2023
Regional Haze SIP submission available for public comment from February
13, 2023, through March 16, 2023. IDNR received and responded to public
comments and included the comments and responses to those comments in
its submission.
On August 2, 2024 (89 FR 63258), the EPA published the NPRM
proposing approval of Iowa's SIP submission as satisfying the regional
haze requirements for the second planning period contained in the CAA
and 40 CFR 51.308. The EPA is now determining that the Iowa Regional
Haze SIP submission for the second RHR planning period meets the
applicable statutory and regulatory requirements in CAA section 169A
and 40 CFR 51.308 and is thus approving Iowa's submission into its SIP.
III. EPA's Response to Comments
The public comment period on the EPA's proposed rule opened August
2, 2024, the date of its publication in the Federal Register and closed
on September 3, 2024. During this period, the EPA received four sets of
comments. One set of comments originated from a group of six
conservation organizations: the Sierra Club, National Parks
Conservation Association, Coalition to Protect America's National
Parks, Interfaith Power and Light, Environmental Law and Policy Center,
and Iowa Environmental Council (collectively referred to as ``the
Conservation Groups'' throughout this document). A second set of 88
nearly identical comment letters were submitted from Iowa Sierra Club
members (collectively referred to as ``Sierra Club members'' throughout
this document). The remaining two sets of comments were submitted from
individual organizations. All the public comments are available in the
docket for this final action via Docket ID Number EPA-R07-OAR-2024-0313
on the <a href="https://www.regulations.gov">https://www.regulations.gov</a> website.
We determined that one comment was not germane to our action, for
the following reasons. One commenter expressed opposition to the
cultivation of cannabis, asserting general air pollution concerns. The
commenter did not provide any tangible connection to the regional haze
requirements or the Iowa submission. The EPA acknowledges the
commenter's concerns; however, the comment is outside the scope of this
action and does not indicate that the EPA's approval of the SIP
submission is inconsistent with the CAA. Oversight of cannabis farms is
unrelated to this regional haze action.
In the rest of this section, the EPA has summarized and provided
responses to the adverse comments received on the NPRM. EPA has also
considered the comments received in support of the NPRM. Having done
so, the EPA is finalizing its approval of the Iowa SIP submission for
the RHR second planning period.
Comment 1: Iowa Sierra Club Members comment that Iowa is not taking
adequate steps to control air pollution from the LGS, WSEC-3, WSEC-4,
George Neal North (GNN), and George Neal South (GNS) coal plants. The
comments state that under the RHR, IDNR must require cost-effective
controls at these plants for both SO<INF>2</INF> and NO<INF>X</INF>.
The commenters request that the EPA reject Iowa's SIP and promptly
issue a strong Federal Implementation Plan (FIP) that will curb haze-
causing pollution at its source. The commenters conclude that haze-
causing pollutants cause health impacts.
Response 1: The EPA disagrees that Iowa has not taken adequate
steps to limit haze-causing pollution and that Iowa's second planning
period SIP submission must include additional SO<INF>2</INF> and
NO<INF>X</INF> controls at LGS, WSEC-3, WSEC-4, GNN, and GNS. The CAA
and the RHR require states to evaluate and determine the emission
reduction measures that are necessary to make reasonable progress
towards natural visibility conditions in Class I areas by
[[Page 37391]]
considering the four statutory factors.\1\ As long as these
determinations are reasonable, states have substantial discretion in
making them, and the EPA will not insist on a particular combination of
analyses and control measures as a condition of approval. The RHR
requires each State to ``submit a long-term strategy (LTS) that
addresses regional haze visibility impairment for each mandatory Class
I Federal area within the State and for each mandatory Class I Federal
area located outside the State that may be affected by emissions from
the State. The LTS must include enforceable emissions limitations,
compliance schedules, and other measures that are necessary to make
reasonable progress.'' \2\ As detailed in the NPRM and the State
submission, Iowa selected two electric generating units (EGUs) with the
largest SO<INF>2</INF> and NO<INF>X</INF> emissions for four-factor
analysis: LGS and WSEC-3. As a result of the four-factor analysis
conducted for LGS and WSEC-3, Iowa required MidAmerican to optimize the
operation of existing scrubber controls and required compliance with
new regional haze SO<INF>2</INF> limits by December 31, 2023. The EPA
finds that Iowa has satisfied the requirement that states determine the
emission reduction measures that are necessary to make reasonable
progress by considering the four factors, and the EPA also finds that
the operational improvements required by Iowa at LGS and WSEC-3 meet
the LTS requirements for the second planning period.
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\1\ CAA section 169(g)(1).
\2\ 40 CFR 51.308(f)(2).
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In addition, the EPA has reviewed power sector emissions data
collected by EPA's Clean Air Markets Program Division (CAMPD) under 40
CFR part 75. This data is publicly available through the CAMPD
Database.\3\ Following the 2023 compliance deadline, the 2024 annual
SO<INF>2</INF> emissions decreased at LGS and WSEC-3 by a combined
total of 11,169 tons, as compared to the 2017-2019 average used as a
baseline in Iowa's 2023 SIP.
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\3\ <a href="https://campd.epa.gov/data">https://campd.epa.gov/data</a>.
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The commenter correctly notes that haze-causing pollutants cause
health impacts. However, as stated in Iowa's submission at section
12.1. Response to Public Comments: (1) The purpose of the RHR is to
restore natural visibility conditions in Class I areas and not to
evaluate health impacts from criteria pollutants in areas outside Class
I areas. Implementation of the National Ambient Air Quality Standards
(NAAQS) is provided for in section 110 of the CAA; and (2) the EPA and
IDNR have stated that the regulatory requirements at 40 CFR 51.308 do
not apply to the NAAQS and do not provide for the requirement that
states consider ancillary benefits. To further substantiate this
position, as IDNR notes, all ambient air quality monitors in Iowa are
currently measuring attainment with the NAAQS. As discussed in the NPRM
and in this notice of final rulemaking, the EPA evaluated Iowa's SIP
submission against the statutory and regulatory regional haze
requirements and determined that it satisfies the requirements. Thus,
the EPA is finalizing its approval of the Iowa SIP submission and has
no obligation to promulgate a FIP.
Comment 2: The Conservation Groups comment that Iowa's cost
analyses for MidAmerican's LGS and WSEC-3 include costs and cost
assumptions that are inconsistent with EPA's Control Cost Manual. The
commenters argue that the EPA must disapprove IDNR's unreasonable use
of a firm-specific interest rate until IDNR and MidAmerican present
sufficient documentation on the underlying assumptions and costs of the
firm-specific interest rate. The Conservation Groups state that because
``IDNR fails to provide any documentation supporting MidAmerican's
inclusion of AFUDC costs, its weighted cost of capital, or its use of a
firm-specific interest rate,'' the EPA must disapprove the SIP
submission for failure to provide proper documentation for its cost
analysis and issue a FIP using an interest rate that is supported by
the record at the time of the final decision.
Response 2: The EPA disagrees with the Conservation Groups'
assertions that the 7.862 percent firm-specific interest rate is
unreasonable, and that MidAmerican did not provide sufficient
justification. IDNR used the tools provided and recommended by the EPA
for calculating control cost estimates at LGS and WSEC-3. In accordance
with EPA's Air Pollution Control Cost Manual (Control Cost Manual),\4\
IDNR requested that MidAmerican provide additional justification to
support the use of a firm-specific interest rate, and that information
is included in appendix D-3 of the state submission. Furthermore, at
the time of the state public comment period, the prime lending rate was
7.75 percent. In section 12.1. Response to Public Comments, IDNR
states, ``differences in costs calculations between those based on a
7.75 percent bank prime rate versus those using the justified firm-
specific interest rate of 7.862 percent are inconsequential.'' Finally,
we note that the bank prime lending rate since the SIP submission by
IDNR has been as high as 8.50 percent. The EPA does not agree that
IDNR's use of a 7.862 percent interest rate is unreasonable and
warrants issuance of a FIP because Iowa's cost analyses satisfied the
requirements of 40 CFR 51.308(f)(2).
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\4\ EPA's ``Air Pollution Control Cost Manual'' is available at:
<a href="https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution">https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution</a>.
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Comment 3: The Conservation Groups' comment that Iowa's cost-
effective analyses failed to justify the truncated 20-year useful life
of SO<INF>2</INF> and NO<INF>X</INF> control options at LGS and WSEC-3
and that such a justification is required by the RHR. The comment
asserts that unjustifiably shorter useful life assumptions skew the
cost analysis, making post-combustion controls seem less cost
effective. The commenters conclude that because of IDNR's failure to
provide a reasonable explanation for the remaining useful life, the EPA
must disapprove the SIP submission and issue a FIP that assumes the
typical 30-year useful life for the control equipment.
Response 3: The EPA disagrees that Iowa's cost analyses are
inconsistent with the Control Cost Manual or the RHR. For
NO<INF>X</INF> controls, Iowa's cost analysis for selective catalytic
reduction (SCR) used 30 years for the equipment life, consistent with
the Control Cost Manual and the commenter's assertion that 30 years is
the appropriate equipment life. Iowa's cost analysis for selective non-
catalytic reduction (SNCR) used 20 years for equipment life, consistent
with the Control Cost Manual.
For SO<INF>2</INF> controls, Iowa concurred with the MidAmerican
cost analyses' useful life estimates. The MidAmerican cost analyses
used a 20-year useful life to evaluate operational improvements to the
existing dry flue gas desulfurization (FGD) systems and new wet FGD
systems. The Control Cost Manual specifies that EPA has generally used
equipment life estimates of 20 to 30 years for analyses using acid gas
scrubbers, although these estimates are recognized to be low for many
installations.\5\ Though EPA generally recommends a 30-year equipment
life for acid gas scrubbers, Iowa's use of a 20-year useful life in its
2023 SIP is not inconsistent with the Control Cost Manual. While we
acknowledge that changing the useful life variable to 30 years in these
analyses may result in a
[[Page 37392]]
higher cost-effectiveness of both wet and dry FGD systems, as
demonstrated in the Conservation Groups' submitted analysis, we do not
agree that assuming a useful life of 30 years would impact the final
control decision, due to the very high capital costs of installing new
wet FGD systems at LGS and WSEC-3 as compared to improved operation of
the existing dry FGD systems, which would incur no equipment related
capital costs. Furthermore, Iowa's useful life assumptions did not
prevent Iowa from requiring new control measures for those sources.
Iowa's 2023 Regional Haze SIP includes cost-effective control measures
that require MidAmerican to optimize the operation of existing dry
scrubber controls at LGS and WSEC-3, which will reduce actual
SO<INF>2</INF> emissions by a combined total of approximately 9,700
tons per year compared to the 2017-2019 emissions baseline. Iowa
concluded that these improvements were necessary to make reasonable
progress towards natural visibility conditions in linked Class I areas.
As discussed in the NPRM and in this notice of final rulemaking, the
EPA has evaluated Iowa's SIP submission against the applicable
statutory and regulatory regional haze requirements. We find the
submission satisfies the regional haze requirements of 40 CFR
51.308(f)(2)(i) regarding both the sources selected for evaluation and
the emission reduction measures necessary to make reasonable progress
during the second implementation period.
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\5\ See EPA Control Cost Manual, section 5, Chapter 1 (Wet and
Dry Scrubbers for Acid Gas Control), at 1-8.
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Comment 4: The Conservation Groups' comment that Iowa's cost
analysis failed to evaluate the highest SO<INF>2</INF> removal
efficiency that could be achieved with upgrades to existing dry FGD
systems and new wet FGD systems at LGS and WSEC-3. The commenters
conclude that the EPA must disapprove Iowa's SO<INF>2</INF> four-factor
analysis for LGS and WSEC-3 and promulgate a FIP requiring dry FGD
system upgrades to achieve at least 95% control, with a floor of 0.05
lb/MMBtu, and include an evaluation of and requirements for a wet FGD
retrofit to achieve an annual average SO<INF>2</INF> rate of 0.03 lb/
MMBtu at LGS and at WSEC-3. The Commenters' specific comments on this
topic are addressed in Comments 4.a through 4.c below.
Comment 4.a: The commenters state that ``data shows that several
coal-fired power plant units with wet scrubbers achieve SO<INF>2</INF>
rates lower than 0.04 lb/MMBtu on an annual basis,'' and the analysis
must evaluate the wet FGD retrofit to achieve an annual average
SO<INF>2</INF> rate of 0.03 lb/MMBtu at LGS and WSEC-3. The commenters
state that ``the EPA has long indicated that states must evaluate
controls at their most efficient levels.''
Response 4.a: The EPA disagrees with the Conservation Groups'
assertion that the EPA must promulgate a FIP requiring wet FGD retrofit
to achieve an annual average SO<INF>2</INF> rate of 0.03 lb/MMBtu at
LGS and WSEC-3. The EPA notes that the quote in the comment summary
stating ``the EPA has long indicated that states must evaluate controls
at their most efficient levels'' is a direct quote from the
Conservation Groups' comment letter. The commenters cite to 70 FR 39166
(July 6, 2005) to support the quoted language. The cited Federal
Register document is titled Regional Haze Regulations and Guidelines
for Best Available Retrofit Technology (BART) Determinations. The
published final rule makes changes to the 1999 iteration of the RHR
after it was challenged in the D.C. Circuit, including ``requir[ing]
the States to consider the degree of visibility improvement resulting
from a source's installation and operation of retrofit technology,
along with the other statutory factors set out in CAA section
169A(g)(2), when making a BART determination.'' \6\ Notably, this
rulemaking pertained to 40 CFR 51.308(e), which contains the BART
guidelines and requirements for the first implementation plans due
under the regional haze program. Therefore, this 2005 preamble is not a
useful resource for interpreting non-BART related requirements for the
second planning period set forth in 40 CFR 51.308(f).
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\6\ 70 FR 39104, 39106 (July 6, 2005).
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Furthermore, the cited page of the Federal Register document does
not support the Conservation Groups' contention. This page covers step
3 of the BART analysis: evaluation of technically feasible
alternatives. In answering the question ``how do I evaluate control
techniques with a wide range of emission performance levels,'' the
preamble states ``[i]t is not [the EPA's] intent to require analysis of
each possible level of efficiency for a control technique as such an
analysis would result in a large number of options. It is important,
however, that in analyzing the technology you take into account the
most stringent emission control level that the technology is capable of
achieving.'' \7\ This section further advises ``[w]hile you must
consider the most stringent level as one of the control options, you
may consider less stringent levels of control as additional options.
This would be useful, particularly, in cases where the selection of
additional options would have widely varying costs and other impacts.''
\8\
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\7\ Id. at 39166.
\8\ Id.
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The BART determinations required by 40 CFR 51.308(e) during the
regional haze program's first planning period are distinct from the
reasonable progress determinations required during the second planning
period under 40 CFR 51.308(f). The first planning period source-
specific BART analysis required states to examine the ``best
available'' system of compliance for eligible sources, while there is
no such requirement for the second planning period under the reasonable
progress regulations at 40 CFR 51.308(f). Therefore, as the
Conservation Groups' argument that Iowa failed to evaluate the highest
SO<INF>2</INF> efficiency that could be achieved with a wet FGD system
is based upon the first planning period requirements for BART controls,
the EPA does not find it to be compelling.
Comment 4.b: For dry FGD systems, the comment asserts MidAmerican
evaluated improvements that would achieve an SO<INF>2</INF> rate of
0.10 lb/MMBtu, which reflects only a 78 percent control efficiency. The
commenters state that Iowa must evaluate FGD upgrades to meet a 90
percent reduction level or an annual average emission rate of 0.05 lb/
MMBtu at both LGS and WSEC-3 and must also impose an SO<INF>2</INF>
emission limit of 0.06 lb/MMBtu on a 30-day rolling average basis at
both units. The Conservation Groups argue that the Control Cost Manual
indicates that in multiple locations, SDA systems are capable of
meeting 95 percent control efficiency while treating coal with sulfur
content up to three percent. The commenters point to the EPA's December
28, 2011, first planning period Oklahoma FIP (76 FR 81728), stating
that the EPA indicated that underperforming SDA scrubbers should be
evaluated at 95 percent control and a floor of a 0.06 lb/MMBtu emission
rate.
Response 4.b: The EPA disagrees with the assertion that Iowa must
evaluate dry FGD system upgrades to achieve at least 90 percent control
efficiency or impose an SO<INF>2</INF> emission limit of 0.06 lb/MMBtu.
The commenters point to the Oklahoma FIP, which was promulgated under
the first planning period, and the specific citation from the comment
letter, which is referring to that planning period's BART
guidelines.\9\ As outlined above in Response 4.a, the requirements for
the second planning period differ from the first planning period. As
the Conservation Groups' argument that Iowa failed to evaluate
[[Page 37393]]
improvements to the dry FGD systems at LGS and WSEC-3 is again based on
first planning period requirements for BART controls rather than second
planning period requirements set forth at 40 CFR 51.308(f), the EPA
does not find it to be compelling.
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\9\ 76 FR 81,728,81,742 (Dec. 28, 2011).
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Comment 4.c: Finally, the comment argues that IDNR's cost-
effectiveness values for new wet FGD systems at LGS and WSEC-3 were
unreasonable in that they failed to evaluate the top level
SO<INF>2</INF> removal efficiency that is achievable. The comment
asserts that once the analysis is corrected, the controls should be
even more cost-effective.
Response 4.c: Iowa's control cost analysis evaluated new wet FGD
systems at LGS and WSEC-3 to achieve an emission limit of 0.06 lb/MMBtu
and found the costs to be over $6,000/ton at LGS and $8,000/ton at
WSEC-3. However, consistent with 40 CFR 51.308(f)(2)(i), IDNR also
considered the other factors (i.e., the time necessary for compliance,
the energy and nonair quality environmental impacts of compliance, and
the remaining useful life of any potentially affected anthropogenic
source of visibility impairment). As detailed in the NPRM and the State
submission, the new wet FGD systems required a longer time necessary
for compliance and presented additional energy and nonair quality
environmental impacts when compared to the improved operation of the
existing dry FGD systems. We acknowledge that evaluating the control at
a lower emission rate may result in a slightly higher cost-
effectiveness of the wet FGD system, as shown in the Conversation
Groups' submitted analysis. However, the EPA does not agree that
evaluating the wet FGD control systems at a rate of 0.03 lb/MMBtu,
compared to 0.06 lb/MMBtu, as used by IDNR, would significantly impact
the control decisions made through the State's complete four-factor
analysis, due to consideration of the other factors and inarguably
higher cost effectiveness of improved operation of the existing dry FGD
systems. We therefore find that Iowa's analysis was reasonable and
resulted in an LTS that achieves reasonable progress for the second
planning period. Iowa has satisfied the requirements of 40 CFR
51.308(f), and the EPA approves Iowa's SIP submission.
Comment 5: The Conservation Groups comment that it appears that the
dry FGD system at LGS is equipped with a scrubber bypass, and the EPA
must evaluate the elimination of the bypass during the four-factor
analysis when promulgating a FIP. The Conservation Groups assert that
IDNR improperly skewed the analysis to make it appear that the facility
is achieving a greater emission reduction than it actually is and
effectively ignores cost-effective pollution reductions.
Response 5: We disagree with this comment. The EPA was unable to
find any data to support this assertion. The Environmental Groups
referenced the attached report, Utility FGD Design Trends, which is
available in the docket for this action, that cited data collected by
the U.S. Energy Information Administration (EIA) for 2008 (EIA-860 data
Schedules 6-G & 6-H).\10\ However, as IDNR stated in section 12.1
Response to Public Comments, EIA-860 data does not support this
assertion. The EIA data for 2023 and previous years shows LGS is not
equipped with FGD bypass.\11\ Furthermore, IDNR stated in section 12.1,
``the emission limits apply at all times, thus the presence or absence
of FGD bypass is irrelevant.''
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\10\ See Weilert, Carl and Emily Meyer, Burns & McDonnell,
Utility FGD Design Trends.
\11\ See <a href="https://www.eia.gov/electricity/data/eia860/">https://www.eia.gov/electricity/data/eia860/</a>.
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Comment 6: The Conservation Groups assert that a new wet FGD system
should also be considered a cost-effective option at WSEC-3 and LGS.
The commenters' analysis asserts a cost-effectiveness of $4,907/ton at
WSEC-3, which the comment argues is below IDNR's threshold and within
the range of the EPA's determinations in the first planning period, and
$6,968/ton at LGS, which is below the cost effectiveness thresholds
used by Colorado, Nevada, and New Mexico. Furthermore, the comment
argues that ``IDNR was wrong to suggest that there is inherent
flexibility on costs, as Congress clearly set requirements for national
consistency throughout the country in implementing the Act's
programs.''
Response 6: The EPA acknowledges that the cost effectiveness of a
new wet FGD system at WSEC-3 and LGS may be within the range of costs
of controls implemented by other states in their LTS. However, the EPA
disagrees that specific controls must be required for Iowa's SIP to
meet the second planning period's criteria. The RHR does not require a
specific cost effectiveness threshold to be applied when states
consider new control measures. Rather, cost effectiveness is one of
four factors to be considered holistically. In this case, IDNR
identified technically feasible control options and reasonably
evaluated the cost effectiveness of controls for both sources. Whether
the cost effectiveness of a new wet FGD system is $6,160/ton at WSEC-3
and $8,920/ton at LGS, as asserted by the MidAmerican analysis, or
$4,907/ton at WSEC-3 and $6,968/ton at LGS, as estimated by the
Conservation Groups, the EPA does not see a compelling basis to dispute
IDNR's final control determination. In comparison, MidAmerican
estimated the cost of the improved operation of existing dry FGD
systems to be less than $300/ton at each facility.
Iowa concluded that the optimization of existing dry scrubbers at
LGS and WSEC-3 was necessary to make reasonable progress towards
natural visibility conditions in linked Class I areas and required
MidAmerican to implement these control measures in its 2023 Regional
Haze SIP. The EPA evaluated Iowa's SIP submission against the
applicable statutory and regulatory regional haze requirements and
finds the submission satisfies the regional haze requirements of 40 CFR
51.308(f)(2)(i).
Comment 7: The Conservation Groups comment that Iowa's control cost
analysis understated the NO<INF>X</INF> removal efficiency of SCR and
SNCR systems at LGS and WSEC-3 and thus requires correction. The
commenters state that MidAmerican evaluated SCR to achieve a
NO<INF>X</INF> rate of 0.05 lb/MMBtu, reflecting 73 percent control
across the SCR system at LGS and 77.6 percent across the SCR system for
WSEC-3. The Conservation Groups argue that SCR systems are designed to
achieve 90 percent or greater NO<INF>X</INF> control efficiency,
resulting in annual average NO<INF>X</INF> emission rates with SCR,
along with existing low NO<INF>X</INF> burners and overfire air, as low
as 0.04 lb/MMBtu or even lower. The commenters state that MidAmerican
also assumed that SNCR at LGS and WSEC-3 would achieve a NO<INF>X</INF>
removal efficiency of 15 percent. The commenters argue that its
analysis determined that SNCR at LGS should have an achievable
NO<INF>X</INF> removal efficiency of 20.9 percent and an annual
NO<INF>X</INF> emission rate of 0.15lb/MMBtu, and SCNR control at WSEC-
3 should have an achievable NO<INF>X</INF> removal efficiency of 21.7
percent and an annual NO<INF>X</INF> emission rate of 0.17 lb/MMBtu.
The Conservation Groups assert that the EPA must promulgate a FIP that
evaluates NO<INF>X</INF> control options at these removal efficiencies.
Response 7: The EPA disagrees with the commenters' assertion that
we must promulgate a FIP evaluating NO<INF>X</INF> controls that
achieve the specified emission rates. As discussed in the response to
Comment 4.a, there is no requirement for the state to evaluate control
equipment at a specified removal efficiency under the second planning
period regulations at 40 CFR
[[Page 37394]]
51.308(f). While it is important to consider the most stringent
emission control level that the technology is capable of achieving,
less stringent levels of control may be considered as well, such as in
the case where the control options have varying costs and impacts.
As detailed in the 2023 SIP submission and appendix D-2 of the
State submission, IDNR conducted its own assessments of NO<INF>X</INF>
controls in which different scenarios were evaluated. In section 12.1
Response to Public Comments, Iowa asserted that the cost-effectiveness
values for SNCR and SCR presented in the Conservation Groups' analysis
are not significantly different than those estimated by the IDNR and,
therefore, do not impact Iowa's control decision that neither SNCR nor
SCR are reasonable at this time. Iowa further stated, ``The DNR finds
that the SNCR and SCR cost-effectiveness values for LGS and WSEC-3 are
unreasonable in comparison to the SO<INF>2</INF> control costs and that
SO<INF>2</INF> emission reductions from Iowa's EGUs provide greater
visibility protections than NO<INF>X</INF> reductions.'' \12\
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\12\ See Iowa's August 15, 2023, submission, at 70.
---------------------------------------------------------------------------
The EPA does not agree that evaluating NO<INF>X</INF> controls at
increased removal efficiencies would impact the State's control
decisions. We find that Iowa's analysis was reasonable and that it
resulted in a LTS that achieves reasonable progress for the second
planning period.
Comment 8: The Conservation Groups comment that MidAmerican's cost-
effectiveness analyses show that both SNCR and SCR must be considered
cost-effective controls for LGS and WSEC-3, as their implementation
costs are within the range of the cost effectiveness thresholds used by
Colorado, Nevada, Minnesota, New Mexico, Arizona, and Washington. The
comment further asserts that IDNR failed to meaningfully respond to
public comments and the FLM's comments regarding cost effectiveness
values and the thresholds established by these other states. The
commenters conclude that it was unreasonable for Iowa to ignore these
comments from the public and FLMs, and the EPA must promulgate a FIP in
which the cost effectiveness of SNCR at LGS and of SCR at WSEC-3 are
considered to be reasonable.
Response 8: The EPA acknowledges that the cost effectiveness of SCR
and SNCR at WSEC-3 and LGS may be within the range of costs of controls
implemented by other states in their LTS. However, as explained in
Response 6, the EPA disagrees that specific controls must be required
for reasonable progress. The EPA also disagrees with the commenters'
assertion that Iowa did not adequately respond to comments.
The EPA reviews each submission against the applicable requirements
of the CAA and RHR. The RHR does not provide a specific cost-
effectiveness or emission threshold which States must meet when
considering installation or upgrade of emission controls under the four
statutory factors. Thresholds used by some states in a reasonable
exercise of the discretion afforded by the CAA and RHR do not bind
other states, nor do they preclude the EPA from finding other cost
effectiveness thresholds (or the decision to forgo using a hard
threshold) are reasonable.
Additionally, the commenters impart a requirement into the
regulations that does not exist by asserting a State must
``meaningfully'' address the comments received. The commenters
incorrectly argue that for a State to adequately respond to public
comments, the State must amend the SIP to align with the comments. This
is incorrect. But it is also irrelevant here. The EPA's role in this
process is to review whether SIP submissions meet minimum federal law
standards for approvability. As set forth in 40 CFR 51.102, ``States
must provide notice, provide the opportunity to submit written comments
and allow the public the opportunity to request a public hearing.'' As
detailed below in Response 24, IDNR provided public notice, provided
the opportunity for the public to submit written comments and held a
public hearing on the SIP revision. It received comments and responded
to those comments. Therefore, Iowa satisfied the requirements of 40 CFR
51.102.
Finally, the EPA disagrees with the commenters' argument regarding
IDNR's response to the FLM's comments during the State and FLM
Coordination. The requirements for this Coordination are set forth in
40 CFR 51.308(i). The only requirement regarding comments by FLMs
states that Iowa ``must include a description of how it addressed any
comments provided by the [FLMs]'' in developing its plan revision.\13\
In the NPRM, the EPA discussed the informal and formal consultations
IDNR conducted with FLMs. Furthermore, the EPA stated ``Iowa responded
to the FLM comments and included the responses in section 11.5 of its
submission to EPA and their public notice, in accordance with the
requirements in CAA section 169A(d) and Sec. 51.308(i)(3).'' \14\ The
commenters did not provide any citation to the CAA or the RHR to
support its assertion that a State is required to ``incorporate into
the SIP the concerns of the agencies responsible for managing the Class
I resources impacted by pollution from the state.'' The EPA disagrees
with the commenters about what is required during the State and FLM
consultations and reiterates its conclusion that Iowa has satisfied the
requirements for consultation as laid out in the CAA and the RHR.
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\13\ 40 CFR 51.308(i)(3).
\14\ 89 FR 63258, 63276 (Aug. 2, 2024).
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Comment 9: The Conservation Groups comment that the EPA must
disapprove Iowa's four-factor analysis because IDNR did not evaluate
potential improvements or optimization to existing control equipment at
WSEC-4. The Conservation Groups assert the EPA cannot approve IDNR's
analysis of emission reductions at WSEC-4 because there are readily
available, cost-effective measures that could be carried out at the
unit to achieve additional SO<INF>2</INF> reductions, including
optimizing the efficiency of the dry FGD scrubber to achieve an annual
emission rate of 0.05 lb/MMBtu. Similarly, the commenters argue that
IDNR's failure to evaluate potential upgrades to the SCR system at
WSEC-4 was arbitrary because the Conservation Groups' analysis
demonstrated the ability for the unit to meet a NO<INF>X</INF> emission
limit of 0.04 lbs/MMBtu for months at a time. The Conservation Groups
conclude that the EPA must promulgate a FIP that evaluates cost-
effective improvements to the SCR system and requires WSEC-4 to meet an
annual SO<INF>2</INF> emission rate of 0.05 lb/MMBtu.
Response 9: The EPA disagrees with the Conservation Groups' comment
that a four-factor analysis is required for WSEC-4. Iowa's reliance on
already-effective controls in lieu of four-factor analyses for WSEC-4
is not inconsistent with the CAA legislative history or EPA's
interpretation and implementation of the CAA's regional haze
requirements.
The EPA stated in the NPRM that Congress determined that ``a
visibility protection program is needed in addition to the [Clean Air
Act]'s National Ambient Air Quality Standards [NAAQS] and Prevention of
Significant Deterioration programs, as further emission reductions may
be necessary to adequately protect visibility in Class I areas
throughout the country.'' \15\ This statement does not say that
Congress determined that every State must analyze the four factors for
all sources, or for sources that are already well
[[Page 37395]]
controlled. Further, the EPA specified that further emissions
reductions ``may be'' necessary, which recognizes that additional
reductions will not always be necessary, depending on the effectiveness
of other existing programs. The preamble to the 2017 RHR states, ``. .
. we expect states to exercise reasoned judgment when choosing which
sources, groups of sources or source categories to analyze.'' \16\
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\15\ 89 FR 63258, 63260 (citing H.R. Rep No. 95-294 at 205).
\16\ 82 FR 3078, 3088 (Jan. 10, 2017).
---------------------------------------------------------------------------
The EPA disagrees that ``IDNR arbitrarily concludes that no further
control analysis is necessary due to WSEC Unit 4's twenty-year-old BACT
determination,'' as the commenters argue. Instead, Iowa evaluated
current control measures at WSEC-4, including applicable facility
permits and actual emission rates, against current information in the
EPA's RACT/BACT/LAER Clearinghouse and demonstrated that the high level
of control already required makes it reasonable to conclude that a full
four-factor analysis would likely result in the conclusion that no
further controls are necessary. The State provided a description of
this analysis in section 5.3.1 of the submittal.\17\ We find that
Iowa's analysis was reasonable.
---------------------------------------------------------------------------
\17\ See Iowa August 15, 2023, submission at 32-33.
---------------------------------------------------------------------------
Comment 10: The Conservation Groups assert that Iowa's
consideration of visibility benefits was unreasonable. The commenters
assert that neither the CAA nor the RHR lists visibility improvement as
a fifth factor in the four-factor analysis and that the EPA has made
clear that, for the second planning period, ``a state should not use
visibility to summarily dismiss cost-effective potential controls.''
Here, they assert that Iowa wrongly rejected nearly all cost-effective
controls based on visibility as an additional factor. The Conservation
Groups also state there are multiple flaws with IDNR's visibility
analysis. They therefore contend that the EPA's approval of IDNR's
visibility benefits analysis is unreasonable, arbitrary, and
capricious, and that the EPA must expressly disapprove IDNR's
consideration of visibility impacts. The Commenters' specific comments
on this topic are addressed in Comments 10.a and 10.b below.
Comment 10.a: The Commenters argue that IDNR provides no regulatory
or statutory basis for applying a multi-step approach that compared
relative sulfate impacts to relative nitrate impacts, resulting in the
selection of controls for SO<INF>2</INF> emissions. The Commenters
state that IDNR's approach to visibility does not comport with the
examples of visibility considerations previously provided by EPA.
Further, commenters note, IDNR considered visibility impacts on the
most impaired days, rather than the maximum daily visibility impact on
all days. The comment argues that IDNR did not explain how its
visibility analysis complies with the RHR and the requirement to select
sources based upon a four-factor analysis.
Response 10.a: The EPA disagrees that Iowa's visibility benefits
analysis in the August 2023 SIP was inconsistent with the CAA or the
RHR. The EPA interprets the CAA and the RHR to allow a State reasonable
discretion to consider the anticipated visibility benefits of an
emission control measure, along with the other factors, when
determining whether the measure is necessary to make reasonable
progress. The CAA is silent as to whether States or the EPA may
consider additional factors in addition to the four statutory
factors.\18\ In our Response to Comments on the 2017 RHR, the EPA noted
that the RHR ``neither requires nor prohibits states from considering
visibility when making reasonable progress determinations. . . .
However, a state that elects to consider an additional factor such as
visibility benefit must consider it in a reasonable way that does not
undermine or nullify the role of the four statutory factors in
determining what controls are necessary to make reasonable progress.''
\19\
---------------------------------------------------------------------------
\18\ See 42 U.S.C. 7491(g)(1).
\19\ Protection of Visibility: Amendments to Requirements for
State Plans 82 FR 3078 (Jan. 10, 2017); Response to Comments on
Protection of Visibility: Amendments to Requirements for State
Plans; Proposed Rule at 186. The EPA has approved or proposed
approval for the following SIP submissions in which States
considered visibility in a reasonable way: Air Plan Approval; OR;
Regional Haze Plan for the Second Implementation Period, 89 FR 81361
(Oct. 8, 2024); Air Plan Approval; Minnesota; Second Period Regional
Haze Plan, 89 FR 56827 (July 11, 2024); and Air Plan Approval; Ohio;
Regional Haze Plan for the Second Implementation Period, 89 FR 71124
(Aug. 30, 2024).
---------------------------------------------------------------------------
Iowa performed its visibility analysis by apportioning the State's
total modeled anthropogenic visibility impairment to LGS and WSEC on
the 20% most impaired days at the linked Class I areas.\20\ In doing
so, the State made several conservative assumptions that resulted in
greater estimated sulfate and nitrate impacts from these two
sources.\21\ For instance, the State's maximum sulfate and nitrate
impacts on all linked Class I areas were selected as the basis for the
analysis. In addition, the LGS and WSEC sources were assumed to emit
the entirety of Iowa's EGU emissions when calculating the factors for
allocating total anthropogenic visibility impairment to these two
sources.\22\
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\20\ See Iowa August 15, 2023, submission at 15.
\21\ Id.
\22\ See 89 FR 63258, 63270-71 (Aug. 2, 2024).
---------------------------------------------------------------------------
Based on this analysis, Iowa estimates that sulfate impacts to
visibility in the linked Class I areas are 4.4 times greater than
nitrate impacts for both LGS and WSEC.\23\ Iowa used this result to
inform its selection of cost-effective SO<INF>2</INF> controls over the
NO<INF>X</INF> control options that were identified using the four
statutory factors for LGS and WSEC. Contrary to the Commenters'
assertion that Iowa ``ignored'' NO<INF>X</INF> controls because they
were more expensive than SO<INF>2</INF> controls, Iowa's application of
data and modeling showing that SO<INF>2</INF> and not NO<INF>X</INF> is
the dominant visibility impairing pollutant, and that information led
Iowa to select SO<INF>2</INF> control measures at LGS and WSEC-3. The
EPA finds that Iowa's visibility analysis is reasonable and consistent
with the CAA.
---------------------------------------------------------------------------
\23\ See Iowa August 15, 2023, submission at 15.
---------------------------------------------------------------------------
Comment 10.b: The comment argues IDNR unreasonably relied on
LADCO's 2028 CAMx PSAT modeling results in selecting only five Class I
areas for its visibility benefit analysis when the State was aware
there were additional Class I areas of concern documented by the NPS.
Response 10.b: The Commenters did not provide a technical basis to
support the claim that it was unreasonable for IDNR to rely on LADCO's
2028 CAMx PSAT modeling results for its visibility benefit analysis.
IDNR utilized LADCO's 2028 PSAT results to identify linked Class I
areas in other States, which is documented in section 2 of the State
submission and summarized in the NPRM. IDNR then used the 2028 PSAT
results to complete its visibility benefits analysis of the five Class
I areas linked to Iowa, as explained in section 5.8 of the State
submission and the NPRM. The EPA finds this approach to be reasonable
and consistent with the CAA and RHR.
Comment 11: The Conservation Groups comment that the EPA must
revise its notice and find that Iowa ``unlawfully and unreasonably
relied on the URP [Uniform Rate of Progress]--a non-statutory factor--
to reject controls at LGS and WSEC-3.'' The comment argues that the EPA
failed to evaluate IDNR's URP assertions in the NPRM. Furthermore, the
Conservation Groups assert that the EPA's review of those assertions is
inconsistent with its review of other actions, namely the EPA's
proposed disapproval of the Missouri SIP on the ground that the ``State
used
[[Page 37396]]
the URP argument to avoid controls.'' The Conservation Groups argue
that projected visibility improvements at Class I areas impacted by
Iowa's sources and the fact that those areas are below their respective
URPs are not valid bases for the EPA to approve Iowa's decision to
forgo additional controls at LGS and WSEC-3.
Response 11: The EPA disagrees that Iowa relied on the URP to
reject controls at LGS and WSEC-3. In evaluating Iowa's control measure
determinations, the EPA finds Iowa met all the requirements of 40 CFR
51.308(f)(2) and that Iowa did not rely on the fact that the Class I
areas impacted by Iowa sources are below their respective URP
glidepaths. Iowa's 2023 SIP states the 2028 projections for the Class I
areas using LADCO's 2016 modeling platform are intended to satisfy the
requirement at 40 CFR 51.308(f)(2)(iv)(E) that the State must consider
the anticipated net effect on visibility due to projected changes in
point, area, and mobile source emissions over the period addressed by
the LTS.\24\
---------------------------------------------------------------------------
\24\ See Iowa August 15, 2023, submission at 48.
---------------------------------------------------------------------------
Additionally, the LADCO modeling data provided by IDNR supported
the conclusion that the linked Class I areas are all below their
respective glidepaths and, therefore, Iowa was not required to conduct
the ``robust demonstration'' detailed under 40 CFR 51.308(f)(3)(ii)(B).
However, IDNR did not rely on that fact to avoid controls; rather the
State plan required additional control measures at two facilities to
further reduce SO<INF>2</INF> emissions and improve visibility in
linked Class I areas. The EPA finds that the URP glidepath information
provided by IDNR in the SIP submission meets the requirements of the
CAA and RHR.
The EPA acknowledges that it recently finalized a change in policy
regarding the role of the URP in the agency's review of second planning
period regional haze SIPs. However, that policy change is not outcome-
determinative in this action. The EPA reviewed Iowa's regional haze SIP
submission under its prior review policy and proposed to approve it
based on application of that policy. The agency is finalizing that
proposed approval in this action. We note that Iowa's regional haze SIP
for the second planning period is approvable under both the prior and
recently announced policies regarding the role of the URP.
Comment 12: The Conservation Groups comment that the EPA must
disapprove IDNR's SIP Submission because the permits for LGS and WSEC-3
contain SO<INF>2</INF> limits in units of lb/hour. The commenters state
that the EPA must promulgate a FIP that requires emission limits in the
permits to be in units of lb/MMBtu. The comment states that, ``by
imposing a lb/hr SO<INF>2</INF> limit rather than a lb/MMBtu limit, the
emission limits fail to require the same level of control over all
levels of operation and do not achieve the emissions rate IDNR said
they are intended to achieve.'' The commenters also state the
NO<INF>X</INF> and SO<INF>2</INF> emission limits for WSEC-4 are based
on lb/MMBtu, and the EPA must act consistently across a SIP, so the
emission limits must be set consistently in terms of lb/MMBtu.
Response 12: The EPA disagrees that the emission limits established
for regional haze must be in units of lb/MMBtu. Neither the CAA nor RHR
prescribes the form that an emission limit must take.
As explained in the SIP submission and the NPRM, WSEC-4 went
through BACT review under the Prevention of Significant Deterioration
(PSD) program for SO<INF>2</INF> and NO<INF>X</INF> in 2003.\25\ The
requirements for determining BACT under the PSD program are not the
same as the requirements for determining reasonable progress under the
regional haze program. Iowa determined that WSEC-4 was already equipped
with all feasible control options for SO<INF>2</INF> and NO<INF>X</INF>
and included its rationale in the State submission. Iowa incorporated
the existing emission limits into the SIP for the purpose of preventing
future visibility impairment as a part of its LTS. The fact that the
existing BACT emission limits for WSEC-4 are in units of lb/MMBtu does
not preclude the State from establishing other emission limits under
the regional haze program.
---------------------------------------------------------------------------
\25\ Iowa's August 15, 2023, submission at 29; 89 FR 63258,
63273 (Aug. 2, 2024).
---------------------------------------------------------------------------
The emission limits are clearly stated in the permits included in
appendix E of the State submission. The regional haze limit established
for SO<INF>2</INF> in Permit Condition 1c. for LGS is 800 lb/hr, on a
30-day rolling average, and includes a footnote stating the limit is
based on 65.6 percent reduction of SO<INF>2</INF> emissions from the
baseline years of 2017 to 2019. The regional haze limit established for
SO<INF>2</INF> in Permit Condition 1c. for WSEC-3 is 770 lb/hr, on 30-
day rolling average, and includes a footnote stating that limit based
on 72 percent reduction of SO<INF>2</INF> emissions from the baseline
years of 2017 to 2019. The percent reductions in the submitted permits
correspond to the levels of control MidAmerican assumed in its four-
factor analysis and reflect the emissions reductions in Iowa's LTS for
reasonable progress.
The permits for LGS and WSEC-3 required compliance with the
regional haze SO<INF>2</INF> limits by December 31, 2023. As described
above in Response 1, the actual SO<INF>2</INF> emissions for LGS and
WSEC-3 for 2024 are available as reported to the CAMPD database.\26\
The actual annual SO<INF>2</INF> emissions at LGS in 2024 is 1,179
tons, which is an 80.2 percent reduction of SO<INF>2</INF> emissions
from the baseline years used in Iowa's 2023 SIP (2017-2019 average).
The actual annual SO<INF>2</INF> emissions at WSEC-3 for 2024 is 1,644
tons, which is a 79.6 percent reduction of SO<INF>2</INF> emissions
from baseline years. These emission reductions resulted in a combined
total decrease of 11,169 tons in actual SO<INF>2</INF> emissions in
2024 compared to the baseline years and exceeded the emission
reductions estimated by MidAmerican in the four-factor analysis.
Therefore, we disagree with commenters' assertion that the emission
limits do not achieve the emission rate that IDNR said they are
intended to achieve.
---------------------------------------------------------------------------
\26\ <a href="https://campd.epa.gov/data">https://campd.epa.gov/data</a>.
---------------------------------------------------------------------------
We also note that the commenters did not raise any specific reason
to suggest that the use of a lb/hr limit is inappropriate. Instead,
they simply assert that a lb/hr limit does not require the same level
of control over all levels of operation and state that the EPA must act
consistently across the SIP by requiring all emission limits to be set
in unit of lb/MMBtu. The EPA disagrees. While there are regulatory
programs where emission limits are typically in the form of lb/MMBtu,
such as a BACT analysis under the PSD program, that is not a
requirement under the RHR, and a variety of units may be reasonable
depending on the circumstances of their use.
Under the specific circumstances present here, the EPA finds that
the emission limits Iowa established for regional haze are appropriate
and meet the requirements of the CAA and RHR.
Comment 13: The Conservation Groups comment that Permit Condition R
in the permits for LGS and WSEC-3 ``exempts the facilities from meeting
the minimum additive injection during periods of boiler start-up'' and
that this condition allows for uncontrolled excess emissions during
startup events. The comment quotes the EPA's proposed partial approval
and partial disapproval of Utah's regional haze SIP submission to
assert that the minimum additive injection rates have ``no defined
parameters for the excess emissions that will occur during periods of
startup, making the limitation less than continuous.'' The commenters
[[Page 37397]]
argue ``the permit exemptions mean that emissions exceeding the normal
operational limits under periods of startup would not be considered to
violate the emission limitations.'' The commenters conclude that the
EPA must disapprove the emission limitations because of the startup
exemption provisions.
Response 13: The EPA disagrees with the Conservation Groups'
assertion that the emission limits for WSEC-3 and LGS are not
continuous, or that Permit Condition 5.R. allows the facilities to
exceed the emission limits during startup. The permits for LGS and
WSEC-3 contain numerical emission limits that apply at all times,
including periods of startup, shutdown, and malfunction (SSM). Permit
Condition 1c., footnote 2 in both permits states that the ``. . .
[l]imit is applicable at all times including periods of Boiler startup,
shutdown, and malfunction.'' We recognize that Permit Condition 5.R.
exempts the Permittee from maintaining the minimum additive injection
rate during startup. However, despite the fact that the minimum
additive injection rate is not required to be maintained during
startup, the facility is still required to comply with the numerical
SO<INF>2</INF> lb/hr regional haze emission limitation during all
periods of operation, including startup.
SIPs can contain ``other control measures, means, or techniques''
per CAA 110(a)(2)(A), and such other measures, means, or techniques do
not need to meet the CAA's definition of an ``emission limitation,''
including the requirement that it apply on a continuous basis.\27\ In
this case, the permits required that MidAmerican develop minimum
additive injection rates ``to maintain high SO<INF>2</INF> control
efficiencies at all operating loads.'' \28\ However, the State's LTS is
based on the numerical emission limits that apply at all times. The
minimum additive injection rates provide a function that is separate
from and supplemental to the numerical permit emission limits.
---------------------------------------------------------------------------
\27\ Environ. Comm. Fl. Elec. Power v. EPA, 94 F.4th 77, 99
(D.C. Cir. 2024).
\28\ Iowa's August 15, 2023, submission at 40.
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The permit at issue in the Utah SIP Submission is not analogous to
the LGS and WSEC-3 permits because the Utah permit included ``an
automatic exemption for SSM events that occur when Intermountain power
plant is operating prior to its closure.'' \29\ The permit also
contained a provision providing that the emission limitations apply at
all times except for periods of SSM or emergency conditions.\30\
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\29\ 89 FR 67208, 67249 (Aug. 19, 2024).
\30\ Id.
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Permit Condition 5.R. is not an emission limitation, and the EPA
disagrees that our partial disapproval of Utah's SIP is relevant to the
evaluation of Permit Condition 5.R. Accordingly, the EPA is approving
the emissions limitations and other control measures in Iowa's SIP
submission.
Comment 14: The Conservation Groups comment that the EPA's
assertion that the permits submitted by Iowa serve as the enforceable
mechanism is unclear, because Iowa's intent regarding which permit
provisions it wanted incorporated into the SIP was unclear. The comment
states that the EPA's proposal indicates it intends to include the
entire permits in the SIP, with the exception of Condition 11, but
IDNR's SIP is unclear as to whether it sought to include Permit
Condition 6 regarding Continuous Emissions Monitoring Systems (CEMS) in
the SIP.
The commenters argue that if Permit Condition 6.C. is included as
part of the SIP, that provision does not serve as the enforceable
mechanism for CEMS because it fails to include requirements that the
monitors accurately measure the pollutants and stack gas volumetric
flow rate for each unit. The comment states that Permit Condition 6.C.
``allows for use of methods that are not [included in] 40 CFR part 75,
which EPA has generally required in the regional haze program.'' The
comment asserts IDNR's approach allows for just two data points for
each 1-hour average, allows for data substitution, and does not require
use of a diluent. The comment further states Condition 6.C.(3)(iii)
provides that ``[i]f the monitor data availability is less than 90.0%,
the owner or operator shall obtain actual emission data by an alternate
testing or monitoring method approved by the Department.'' The
commenters argue that the EPA is without authority to approve the
provision that allows for alternative testing into the SIP.
Response 14: The EPA disagrees that Iowa's intent regarding the
permits to be incorporated into the SIP is unclear or that the permit
conditions are not enforceable. The transmittal letter included with
Iowa's 2023 SIP submission states, ``The air construction permits are
provided in appendix E for adoption into the SIP, with the exceptions
of Condition 11 in permit numbers 05-A-031-P6 and 75-A-357-P9 and
Condition 6 in permit 03-A-425-P4.'' Furthermore, as the commenter
noted, the EPA's NPRM proposed to incorporate the entire permits into
the SIP with the exceptions of permit Condition 11 for LGS and WSEC-3
and permit Condition 6 for WSEC-4.\31\
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\31\ 89 FR 63258, 63272 (August 2, 2024).
---------------------------------------------------------------------------
Permit Condition 6 in the submitted permits for LGS (permit no. 05-
A-031-P6) and WSEC-3 (permit no. 75-A-357-P9) are clearly intended to
be incorporated into the SIP and contains the requirements for the
SO<INF>2</INF> CEMS. Additionally, the SO<INF>2</INF> limit contained
in Permit Condition 1c. Regional Haze Limit has a footnote stating that
``Compliance with the limit is based on continuous emissions monitoring
as specified in Permit Condition 6.'' Permit Condition 6.A. requires
SO<INF>2</INF> CEMS to meet EPA standards at 40 CFR part 60, appendix B
Performance Specifications 2 and 6 and 40 CFR part 60, appendix F.
Permit Condition 6.B. requires CEMS for SO<INF>2</INF>, and either
O<INF>2</INF> or CO<INF>2</INF> to be operated and the data recorded
during all periods of operation. Permit Condition 6.C. includes data
requirements.
The commenters' assertion that the permit provision 6.C does not
serve as the enforceable mechanism for CEMS is unclear. The permits as
a whole are enforceable and serve as the enforceable mechanism for the
SO<INF>2</INF> emission limits for regional haze. As stated in permit
conditions 4.C. for LGS and WSEC-3, both units are subject to
continuous emission monitoring requirements at 40 CFR part 75 under the
federal Acid Rain program. The emissions data collected through CEMs
are electronically submitted to the EPA CAMPD and made publicly
available online.\32\
---------------------------------------------------------------------------
\32\ <a href="https://campd.epa.gov/data">https://campd.epa.gov/data</a>.
---------------------------------------------------------------------------
As described in the SIP submittal and the NPRM, appendix E also
includes the current permit for WSEC-4 (permit no. 03-A-425-P4) to
incorporate its existing SO<INF>2</INF> and NO<INF>X</INF> BACT
emission limits into Iowa's SIP.\33\ The emission limits are contained
in Condition 10.A., and there is a footnote stating compliance with the
emission limits shall be demonstrated through the use of CEMS.
Conditions 12 and 16 contain the CEMS requirements for that permit.
Condition 13 states the unit is subject to monitoring requirements
under the Acid Rain program.
---------------------------------------------------------------------------
\33\ 89 FR 63258, 63272 (August 2, 2024).
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The EPA notes that the quote in the comment summary stating that
permit Condition 6.C. ``allows for use of methods that are not
[included in] 40 CFR part 75, which EPA has generally required in the
regional haze program'' is a direct quote from the Conservation
[[Page 37398]]
Groups' comment letter. That assertion is inaccurate. There is no
requirement at 40 CFR 51.308(f) for second planning period regional
haze SIPs to comply with 40 CFR part 75. As explained in response 4.a
above, the requirements for the second planning period differ from the
first planning period. First planning period requirements at 40 CFR
51.308(e)(2) allow states an option to implement or require
participation in an emissions trading program rather than requiring
sources to implement BART. For first planning period SIPs that include
an emissions trading program, there are requirements for monitoring,
recordkeeping, and reporting provisions to comply with part 75. There
are no such requirements for second planning period SIPs.
Iowa has broad discretion under 40 CFR 51.308(f) to determine
appropriate compliance demonstration methodologies. For the hourly
SO<INF>2</INF> emission limits, Iowa has proposed that the affected
sources operate and maintain a CEMS. The EPA notes that, although it is
not a requirement of the regional haze program, the CEMS requirements
in the submitted permits adhere closely to the requirements in 40 CFR
part 75.
The commenter referenced Permit Condition 6.C.(2) which allows the
facility to calculate emissions based on two data points and that the
permit does not require the use of a diluent. Regarding the use of two
data points, the EPA notes that 40 CFR 75.10(d)(1) allows affected
facilities to calculate emissions based on two data points. Permit
Condition 6.A. requires O<INF>2</INF> or CO<INF>2</INF> to be monitored
and Permit Condition 6.C.(2) requires CO<INF>2</INF> to be used in the
calculation demonstrating compliance with the SO<INF>2</INF> emission
limit. Permit condition 6.C.(3)(iii) is comparable with the standard
missing data procedures for SO<INF>2</INF> at 40 CFR 75.33(b). Although
Iowa's approach when monitoring data availability is less than 90
percent is not verbatim with Part 75, the EPA finds the State's
approach is reasonable to ensure that the emissions are accurately
calculated during such periods. Furthermore, Iowa SIP-approved
regulations at 567 IAC 25.1 contain provisions on testing and sampling
of new and existing equipment. As required by 567 IAC 25.1(9)c, ``. . .
all stack sampling and associated analytical methods used to evaluate
compliance with emission limitations of 567--Chapter 23 or required in
a permit issued by the department pursuant to 567--Chapter 22 or 33
shall be conducted using the methodology referenced in this rule.''
The EPA did not observe any deficiencies related to the State's
proposed compliance demonstration methodology for the hourly
SO<INF>2</INF> emission limitations. Due to the requirements to monitor
emissions at all periods of operation and the public availability of
emissions data, the EPA finds that the submitted permits establish
enforceable emission limits in the State's LTS.
Comment 15: The Conservation Groups comment that the permit
provisions for additive injection monitoring devices are not
enforceable because (1) the provisions fail to specify the type of
equipment required, leaving it to the source's discretion; and (2) the
provisions provide sources with discretion on whether to include
recorders with the monitoring devices for the additive injection. The
comment concludes that the EPA must promulgate a FIP that (1) requires
sources to report the manufacturer's recommendations, instructions, and
operating manuals, or the facility-specific operation and maintenance
plan and the facility's compliance with the manufacturer's instructions
and manuals, or the facility-specific operation plan; and (2) requires
the permit to include the criteria for determining the averaging period
for the minimum injection rate.
Response 15: The NPRM does not include discussion of the additive
injection monitoring devices because, for regional haze purposes, the
SO<INF>2</INF> limits in the permits satisfy the LTS requirement to
include enforceable emissions limitations at 40 CFR 51.308(f)(2). The
established additive injection rates are not the direct compliance
demonstration methodology for the federally enforceable emission limits
that MidAmerican must meet at LGS and WSEC-3. The SO<INF>2</INF> CEMS
serve that purpose. Finally, Condition 12.B.(4) requires the owner or
operator of any facility required to install a continuous monitoring
system to provide quarterly reports to the state.
In the NPRM, the EPA found that Iowa had satisfied the requirements
for the LTS in Sec. 51.308(f)(2). Neither the additive injection rate
nor the additive injection rate monitoring was necessary to make that
determination, and there is no reason for the EPA to disapprove the
permit conditions. The EPA finds the emission limits are enforceable
and is therefore approving them in this action.
Comment 16: The Conservation Groups comment that Iowa's regional
haze permit provisions in Condition 5 subsections P, Q, and R do not
contain adequate reporting requirements. The commenters assert that
there are no requirements for the facility to report the following: (1)
CEMS monitoring data, (2) completion date of the Lime Spray Dryer
enhancements, (3) records of enhancements, (4) information regarding
the additive injection rate to the LGS Lime Spray Dryer, (5)
information regarding the averaging period (if applicable), and (6)
corrective actions taken regarding the additive injection rate. The
comment concludes that the EPA must disapprove the regional haze
emission limitations because they fail to contain reporting provisions
necessary for enforcement and include those provisions in a FIP.
Response 16: The EPA disagrees that the regional haze emission
limitations do not contain reporting necessary for enforcement and
notes the Conservation Groups' assertion that the permit does not
require reporting is inaccurate. Permit Condition 1c. of the permits
incorporated into the SIP contain SO<INF>2</INF> emission limits of 800
lb/hr at LGS and 770 lb/hr at WSEC-3 for regional haze, as detailed in
Iowa's LTS. As stated in Condition 1c., compliance with the
SO<INF>2</INF> limits is based on CEMS data, as specified in Permit
Condition 6. Permit Condition 6.B. requires the data to be recorded
during all periods of operation including period of startup, shutdown,
malfunction, or emergency conditions, except for CEMS breakdowns,
repairs, calibration checks, and zero and span adjustments. Permit
condition 12.B.(3) requires reports on the operation of the emission
units or control equipment outside of the operating parameters
specified in Permit Condition 5 in accordance with the schedule set
forth in 567 IAC 24.1. Permit Condition 12.B.(4) requires quarterly
CEMS reports, and 12.C. requires all data, records, reports,
documentation, construction plans, and calculations to be maintained.
As stated above, and in Permit Condition 4.C., both facilities are
subject to CEMS requirements at 40 CFR part 75 under the Acid Rain
program. The emissions data collected through CEMs are electronically
submitted to the EPA Clean Air Markets Program Data and made publicly
available online. Furthermore, both facilities are required to maintain
a Title V Operating Permit. The Title V Operating permit requires the
permittee to submit semi-annual monitoring reports and annual
compliance certifications.
The federally enforceable emission limits in Permit Condition 1c.
are the basis of Iowa's LTS for regional haze. The operating
requirements in Condition 5 subsections P, Q, and R do not impact the
federally enforceable emission limits that MidAmerican must
[[Page 37399]]
meet at LGS and WSEC-3, which apply at all times. In the NPRM, the EPA
found that Iowa had satisfied the requirements for the LTS in Sec.
51.308(f)(2), including the requirement to establish enforceable
emission limitations. The EPA finds the emission limits are enforceable
and is therefore approving them in this action.
Comment 17: The Conservation Groups comment that the conditions of
the permits fail to meet public notice and comment requirements because
the minimum additive injection rate and averaging period for the
minimum injection rate were determined through a required
SO<INF>2</INF> emissions study after the permit was issued. The
Conservation Groups argue that ``EPA cannot approve a SIP that allows a
state to revise the SIP without public notice and comment and
submitting the revisions to EPA for review and action.''
Response 17: The EPA disagrees with the Conservation Groups that
the permit conditions fail to meet public notice and comment
requirements. The EPA further disagrees that we are required to
disapprove the SIP based upon these permit conditions. Permit Condition
5.Q. in the Regional Haze Requirements in the permit for LGS
specifically states that ``[w]ithin 60 operating days after completion
of the Lime Spray Dryer FGD (CE1B) enhancements, the owner or operator
shall conduct an SO<INF>2</INF> emissions study to determine the
minimum additive injection rate to achieve SO<INF>2</INF> reduction of
65.6 percent below the average of 2017-2019 baseline emissions. The
minimum additive injection rate shall be determined during varying
boiler operating loads.'' The argument put forth by the Conservation
Groups regarding Permit Condition 5.Q. ignores Permit Condition 5.P.,
which states ``The owner or operator shall complete Lime Spray Dryer
FGD (CE1B) enhancements to achieve the SO<INF>2</INF> emission limit
specified in condition 1c. by December 31, 2023.'' Condition 1c. sets a
regional haze limit for SO<INF>2</INF> of 800 lb/hr, and the footnote
to the limit states it is ``based on 65.6 percent reduction of
SO<INF>2</INF> emissions from the baseline years of 2017 to 2019.''
The provisions for WSEC-3 are identical, except Permit Condition
1c. sets the regional haze SO<INF>2</INF> limit at 770 lb/hr. In
reading together Permit Conditions 1c., 5.P., and 5.Q., MidAmerican is
required to meet the 800 lb/hr SO<INF>2</INF> limit at LGS, which is a
65.6 percent reduction of SO<INF>2</INF> emissions from the baseline
years of 2017 to 2019, and the 770 lb/hr limit at WSEC-3, which is a 72
percent reduction of SO<INF>2</INF> emissions from the baseline years
of 2017 to 2019.
Furthermore, Permit Condition 5.R. requires MidAmerican to
``maintain the Lime Spray Dryer FGD (CE1B) minimum additive injection
rate at the rates determined during the SO<INF>2</INF> emissions study
at the corresponding boiler loads.''
As stated in the NPRM, the construction permits were modified to
implement the operational improvements at the units and establish
permanent emission limits for Iowa's regional haze LTS.\34\ 40 CFR
51.308(f)(2) requires each state to submit a LTS with its periodic
revision of the SIP for regional haze. The LTS ``must include the
enforceable emissions limitations, compliance schedules, and other
measures that are necessary to make reasonable progress.'' \35\ The
permits for LGS and WSEC-3 establish federally enforceable
SO<INF>2</INF> limits for these units and require compliance with the
limit by December 31, 2023. The NPRM does not include discussion of the
SO<INF>2</INF> emission studies or minimum additive injection rates
because, for regional haze purposes, the SO<INF>2</INF> limits in the
permits satisfy the LTS requirements in the RHR. In its SIP submittal,
IDNR stated the purpose of the SO<INF>2</INF> emissions studies is to
determine the minimum additive injection rate needed by the Lime Spray
Dryer FGD to meet this limit and ``maintain high SO<INF>2</INF> control
efficiencies at all operating loads.'' \36\
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\34\ 89 FR 63258, 63272 (Aug. 2, 2024).
\35\ 40 CFR 51.308(f)(2).
\36\ Iowa's August 15, 2023, submission at 40.
---------------------------------------------------------------------------
The permit conditions require IDNR to approve the study results,
and, as quoted above, require MidAmerican to maintain the additive
injection rate established by the study and approved by IDNR. All
permit conditions are federally enforceable, as required by 40 CFR
51.308(f)(2). Thus, the study results do not alter the permit
conditions or the federally enforceable emission limits for
SO<INF>2</INF> but serve to enhance operation of the Lime Spray Dryer
FGD.
The commenters cite to section 110(l) of the CAA to support the
contention that the study results will result in revision of the SIP
without required public participation. This provision of the CAA states
``[e]ach revision to an implementation plan submitted by a State under
this chapter shall be adopted by such State after reasonable notice and
public hearing.'' \37\ IDNR provided reasonable notice and a public
hearing on the proposed SIP revision and followed the requirements
regarding public hearings for plan revisions set forth in 40 CFR
51.102.
---------------------------------------------------------------------------
\37\ 42 U.S.C. 7410(l).
---------------------------------------------------------------------------
The opportunity to comment on the permit conditions requiring
SO<INF>2</INF> emissions studies to determine the minimum additive
injection rate arose twice, during the public notice and comment period
required for the construction permit under 567 IAC 33.3(17), and again
during the public notice and comment period for IDNR's proposed SIP
revision for the regional haze second planning period.
Iowa has not submitted a proposed SIP revision that seeks further
revision of the SIP without notice and comment, and the EPA is
therefore approving Iowa's SIP revision.
Comment 18: The comment states that the Lime Spray Dryer
enhancements and the SO<INF>2</INF> emissions study results were due by
December 31, 2023, but were not included in the docket for this action.
The comment concludes that the EPA must disapprove the conditions in
the LGS and WSEC-3 construction permits and issue a FIP containing all
the elements necessary for practical enforceability.
Response 18: The EPA disagrees with the Conservation Groups'
contention that the EPA must disapprove the SIP revision because IDNR
did not update their submission to include the emission study results.
As previously stated, the LTS must include enforceable emissions
limitations, compliance schedules, and other measures that are
necessary to make reasonable progress.\38\ The SO<INF>2</INF> emission
studies and the established additive injection rates do not impact the
federally enforceable emissions limits that MidAmerican must meet at
LGS and WSEC-3. In the NPRM, the EPA found that Iowa had satisfied the
requirements for the LTS in Sec. 51.308(f)(2). The emission study
results were not necessary to make that determination, and there is no
reason for the EPA to disapprove the permit conditions. Therefore, the
EPA is approving the submitted source-specific permits into the Iowa
SIP.
---------------------------------------------------------------------------
\38\ 40 CFR 51.308(f)(2).
---------------------------------------------------------------------------
Comment 19: The Conservation Groups comment that Iowa did not
provide a rationale to support the use of a 50 percent contribution
threshold for source selection and that the State must evaluate control
measures for GNN and GNS. The comment also states that the EPA did not
provide justification to support why selecting the two largest sources
was sufficient when other States have selected a higher number of
sources. The commenters state IDNR's source selection methodology
results in
[[Page 37400]]
the selection of sources that contributed a lower EWRT*Q/d value at
Class I areas than GNN and GNS, and they argue this is an unreasonable
outcome. The Conservation Groups conclude that GNN and GNS have
relatively high SO<INF>2</INF> emissions, and thus the EPA must find
IDNR's source selection methodology to be arbitrary and evaluate FGD
upgrades at GNN and GNS in a FIP.
Response 19: The EPA disagrees that IDNR's source selection
methodology was arbitrary, and that the EPA therefore must promulgate a
FIP requiring FGD upgrades at GNN and GNS. As explained in the NPRM,
the RHR does not require States to consider evaluating controls for all
sources, all source categories, or any or all sources in a particular
source category. Rather, States have discretion to choose any source
selection methodology or threshold that is reasonable, provided that
the choices they make are reasonably explained.\39\ To this end, the
RHR requires that a State's SIP submission must include ``a description
of the criteria it used to determine which sources or groups of sources
it evaluated.'' \40\ The technical basis for source selection, which
may include methods for quantifying potential visibility impacts such
as emissions divided by distance metrics, trajectory analyses,
residence time analyses, and/or photochemical modeling, must also be
appropriately documented, as required by 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------
\39\ 89 FR 63258, 63263 (August 2, 2024).
\40\ 40 CFR 51.308(f)(2)(i).
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In this instance, the EPA proposed to find that the information and
explanation included in Iowa's SIP submittal indicated that the State
developed a methodology and examined a reasonable set of sources,
including its two EGUs with the largest SO<INF>2</INF> and
NO<INF>X</INF> emissions, and this analysis resulted in emission
reduction measures necessary to make reasonable progress for the second
implementation period.\41\ As such, Iowa satisfied its RHR obligations
under 40 CFR 51.308(f)(2) through consideration and reasonable
explanation of the methodology by which it selected and analyzed the
particular sources that have the largest contribution to visibility
impairment in Class I areas. In the NPRM, the EPA stated that the
evaluation of these two sources had the potential to meaningfully
reduce Iowa's contributions to visibility impairment in Class I areas.
The EPA reviewed 2024 CAMPD data to substantiate the relative
importance of emission reductions at LGS and WSEC-3 as compared to
annual emissions from all EGUs in Iowa, the emission reductions at LGS
and WSEC-3 contributed to a decrease in 2024 annual SO<INF>2</INF>
emissions for all Iowa EGUs by 71 percent from baseline years.
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\41\ 89 FR 63258, 63270 (August 2, 2024).
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As stated in the NPRM, the core component of a regional haze SIP
submission is a LTS that addresses regional haze in each Class I area
within a State's borders and each Class I area that may be affected by
emissions from the State. The LTS must include the enforceable
emissions limitations, compliance schedules, and other measures that
are necessary to make reasonable progress, as determined pursuant to
(f)(2)(i) through (iv). The amount of progress that is ``reasonable
progress'' is based on consideration of the four statutory factors in
CAA section 169A(g)(1) in an evaluation of potential control options
for sources of visibility impairing pollutants, which is referred to as
a ``four-factor'' analysis. The outcome of that analysis is the
emission reduction measures that a particular source or group of
sources needs to implement in order for the submitting state to make
reasonable progress towards the national visibility goal.\42\ Emission
reduction measures must be represented by ``enforceable emissions
limitations, compliance schedules, and other measures'' (i.e., any
additional compliance tools) in a State's LTS in its SIP.\43\
---------------------------------------------------------------------------
\42\ See 89 FR 63258, 63263 (August 2, 2024); 40 CFR
51.308(f)(2)(i).
\43\ See 40 CFR 51.308(f)(2).
---------------------------------------------------------------------------
Therefore, the outcome of a State's source selection process and
subsequent evaluation of technically feasible and cost-effective
emissions controls by considering the four factors determines what
constitutes the State's LTS for that particular implementation period.
IDNR's source selection process and evaluation of technically feasible
and cost-effective controls resulted in a LTS that includes the
enforceable emissions limitations, compliance schedules and other
measures that are necessary to make reasonable progress. Therefore, the
EPA finds Iowa's source selection and consideration of the four
statutory factors to be reasonable and compliant with the RHR
requirements.
Comment 20: The Conservation Groups argue that the SO<INF>2</INF>
and NO<INF>X</INF> control systems at GNN and GNS are not achieving the
levels of control the pollution control systems are designed to
achieve. For dry FGD systems at GNN and GNS, the Groups assert an
evaluation of controls for these units should presume dry FGD systems
are capable of achieving at least 90 percent SO<INF>2</INF> removal.
The commenters conducted a cost effectiveness analysis of dry FGD
upgrades with the additional use of lime at GNN and GNS and concluded
that these upgrades are cost effective and within the range of both
cost thresholds other States have used and the costs that IDNR found
reasonable for similar SO<INF>2</INF> pollution control upgrades at LGS
and WSEC-3.
The commenters also argue that NO<INF>X</INF> controls at GNN and
GNS are operating below the standard efficiency rates for SNCR, and the
facilities have not had a significant decrease in NO<INF>X</INF>
emission rates per MMBtu. The comments conclude that the EPA needs to
promulgate a FIP that fully analyzes SO<INF>2</INF> and NO<INF>X</INF>
controls at GNN and GNS through a four-factor analysis.
Response 20: The EPA disagrees with the Conservation Groups'
conclusion that it must promulgate a FIP and conduct a four-factor
analysis to evaluate controls at GNS and GNN. The EPA has responded to
the Conservation Groups' comment regarding source selection in Response
20. The Conservation Groups' comments regarding pollution controls at
GNS and GNN facilities are beyond the scope of this rulemaking because
this rulemaking relates solely to Iowa's regional haze SIP revision,
and Iowa did not select those sources for four-factor analysis.
Therefore, neither the State nor the EPA has evaluated the efficiency
rates of controls at GNS or GNN as a part of this action. As explained
above, the RHR does not require States to consider controls for all
sources, all source categories, or any or all sources in a particular
source category, and the EPA finds that Iowa has satisfied the
requirements of 40 CFR 51.308(f)(2)(i) related to evaluating sources.
Comment 21: The Conservation Groups comment that the EPA must
disapprove Iowa's SIP submission because IDNR failed to meet the CAA
and RHR requirements for FLM consultation. The comment argues that IDNR
failed to meaningfully consider or incorporate any of the FLM's
suggestions into the SIP. Furthermore, because the Conservation Groups
assert that the EPA must disapprove Iowa's source selection method and
four-factor analysis, they further argue that the FLM consultation was
based on a SIP revision that did not meet the required statutory and
regulatory requirements of the CAA and RHR and therefore, must also be
disapproved.
Response 21: The EPA disagrees that Iowa did not meet the
requirements for FLM consultation in CAA 169A(d) and 40 CFR 51.308(i).
As described above in Response 8, IDNR met all of the FLM
[[Page 37401]]
consultation statutory and regulatory requirements.
The requirements for FLM coordination are set forth in CAA 169A(d)
and 40 CFR 51.308(i). The only mandate in regard to comments by FLMs
states that Iowa ``shall include a summary of the conclusions and
recommendations of the Federal land managers in the notice to the
public'' \44\ and ``must include a description of how it addressed any
comments provided by the [FLMs]'' in developing its plan revision.\45\
The commenters did not provide any citation to the CAA or the RHR to
support its assertion that a state is required ``to meaningfully
consider and incorporate into the SIP the concerns of the agencies
responsible for managing the Class I resources impacted by pollution
from the state.'' \46\
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\44\ CAA 169A(d).
\45\ 40 CFR 51.308(i)(3).
\46\ Conservation Organization' Comments on EPA's Proposed
Approval of Iowa's Draft State Implementation Plan Regional Haze
Second Implementation Period at 28.
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Sections 11.3 Informal FLM Source Selection and LTS Discussions and
11.4 Formal FLM Consultation of Iowa's SIP revision contain
documentation of the State's consultation outreach with NPS, FWS, USFS
and responses to FLM comments during the consultation outreach.\47\
This included meeting with FLMs on January 20, 2022, providing an
October 11, 2022, draft of the regional haze plan explicitly for the
purpose of FLM consultation, and meeting with FLMs on November 3, 2022.
Additionally, the NPS met with IDNR again on November 29, 2022, to
present their preliminary comments.
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\47\ Iowa's August 15, 2023, submission at 61-62.
---------------------------------------------------------------------------
Section 11.5 Response to FLM Comments Received During Formal FLM
Consultation contained Iowa's responses to comments received as part of
the October 2022 FLM draft review process.\48\ Notably, both FLM
comment letters provided generally positive comments on the State's FLM
consultation and the SIP's organizational structure, content,
analytical techniques, and the SO<INF>2</INF> reductions required from
LGS and WSEC-3.\49\ In addition to the October 2022 FLM consultation
draft process, IDNR provided opportunity for review and comment on the
February 2023 public draft. The NPS used this opportunity to provide
additional comments which are included in section 12.1.2 Comments from
the National Park Service, along with IDNR's responses to the
comments.\50\ Additionally, as described in section 11.1 Regional
Discussions, Iowa participated in the regional planning organization
(RPO), Central States Air Resource Agencies (CenSARA), which included
FLM representatives on regular planning calls between 2017 and
2023.\51\
---------------------------------------------------------------------------
\48\ Id. at 62-65.
\49\ Id. at appendix F.
\50\ Id. at 66-67.
\51\ Id. at 61.
---------------------------------------------------------------------------
A key element of 40 CFR 51.308(i)(2) is that consultation occur
early enough in a State's policy analyses of its LTS so that
information and recommendations provided by the FLMs can meaningfully
inform a State's decisions on the LTS.\52\ 40 CFR 51.308(i)(2) requires
the FLM consultation to happen 60 days before the public notice.
Consistent with the preamble of the EPA's 2017 RHR, IDNR made a good
faith effort to involve the FLMs early in development of the LTS. IDNR
used the comments and feedback from the October 11, 2022, to December
9, 2022, FLM consultation draft to inform the final control
determinations contained in the draft provided for the public notice
and comment period starting on February 13, 2023. Iowa's August 2023
SIP submission also contains a commitment to continuing consultation
with FLMs through regional planning activities or by separate calls as
requested by FLMs to address 40 CFR 51.308(i)(4).\53\
---------------------------------------------------------------------------
\52\ 82 FR 3078, 3116 (Jan. 10, 2017).
\53\ Iowa August 15, 2023, submission at 61.
---------------------------------------------------------------------------
For the reasons stated above, it is our determination that IDNR
adequately conducted FLM consultation and has thus fulfilled the
requirements of the CAA and RHR.
Comment 22: The Conservation Groups comment that the EPA's approval
of Iowa's State-to-State consultation violates the CAA and the RHR
because Iowa's four-factor analyses did not meet the requirements of
the Act or the RHR. The commenters state that the EPA must issue a FIP
that corrects the errors in IDNR's four-factor analyses and includes a
consultation with South Dakota.
Response 22: The EPA disagrees with the commenters' assertion that
Iowa did not meet the requirements for State-to-State consultation in
40 CFR 51.308(f)(2)(ii). Sections 11.1 Regional Discussions and 11.2
Individual State Consultation of Iowa's SIP submission contained
documentation of Iowa's consultation with RPOs and individual
States.\54\ IDNR regularly participated in regional planning activities
through the planning organizations, CenSARA and the Lake Michigan Air
Directors Consortium. In addition to regional planning calls, Iowa also
had individual State consultations with three States (Minnesota,
Michigan, and Missouri) containing the five linked Class I areas in its
2023 SIP submission: Isle Royale, Seney, Boundary Waters, Voyageurs,
and Hercules-Glades. Documentation of consultation with each State is
contained in appendix H to Iowa's submittal.
---------------------------------------------------------------------------
\54\ Id.
---------------------------------------------------------------------------
Consistent with the preamble of the EPA's 2017 RHR, IDNR made a
good faith effort to share its four-factor analyses and associated
technical information with other States through its participation in
regional planning calls and individual State consultations.\55\ IDNR
consulted with States reasonably expected to contribute to visibility
impairment in Iowa's linked Class I areas for the second planning
period. As stated in the 2017 RHR, ``the consultation provisions were
intended to foster and facilitate regional solutions, not to mandate
specific outcomes.'' \56\
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\55\ See 82 FR 3078, 3116 (Jan. 10, 2017).
\56\ Id. at 3088.
---------------------------------------------------------------------------
As explained in detail in the NPRM, the EPA finds that Iowa's
August 2023 SIP submission meets all of the statutory and regulatory
requirements of the CAA and RHR.\57\ Furthermore, the EPA finds that
IDNR fulfilled the requirements for consultation with other States
reasonably expected to contribute to visibility impairment in Iowa's
linked Class I areas for the second planning period through its
participation in regional planning calls and individual State
consultations.\58\ Thus, the EPA proposes approval of Iowa's SIP and
concludes a FIP is unnecessary.
---------------------------------------------------------------------------
\57\ 89 FR 63258, 63276 (Aug. 2, 2024).
\58\ Id.
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Comment 23: The Conservation Groups comment that the EPA's proposed
action failed to consider environmental justice impacts from GNN and
GNS. The commenters also assert that Iowa's SIP lacks any consideration
of environmental justice. The comment also states that, according to
EPA's EJ Screen and Mapping Tool, the communities within a 20-mile
radius of GNN, LGS, and WSEC rank ``above average'' in risk for
respiratory health impacts as compared to other States' census block
groups and that the socioeconomic indicator of low income is higher
than 50 percent. The commenters also state that the environmental
justice indices for PM<INF>2.5</INF> and ozone are high for the
communities surrounding LGS; the ozone environmental justice index is
of considerable concern at GNN; PM and ozone are above the State median
percentile at WSEC; and the people of
[[Page 37402]]
color percentiles range from 73rd to 88th percentile at the three
facilities. The Conservation Groups conclude that the EPA must
promulgate a FIP for Iowa sources and establish emission limitations
that reduce impacts in both Class I areas and environmental justice
communities.
Response 23: Neither the CAA nor the RHR require an evaluation of
environmental justice with regard to a regional haze SIP. The focus of
the regional haze SIP for Iowa is SO<INF>2</INF> and NO<INF>X</INF>
emissions as they impact visibility in Class I areas. This action
addresses two EGU sources (LGS and WSEC) of air pollution impacting
Class I areas. As discussed in the NPRM and in this final rule, the EPA
has evaluated Iowa's SIP submission against the statutory and
regulatory regional haze requirements and determined that it satisfies
those minimum requirements.
Comment 24: The Conservation Groups comment that Iowa did not
provide meaningful access for persons with limited English proficiency
to review and comment on the draft SIP because they did not provide a
public translation of the notice in any language other than English.
The commenters assert that the socioeconomic indicator for limited
English-speaking households in communities surrounding GNN, LGS, and
WSEC range from 74 to 89 percent.
Response 24: In reviewing Iowa's August 15, 2023, Regional Haze SIP
revision, the EPA found that IDNR satisfied the public notice and
comment requirements for the SIP revision. Iowa provided an opportunity
to submit written comments and request a public hearing. IDNR made the
SIP submission available for public comment from February 13, 2023, to
March 16, 2023.\59\ The publication included notification of the 30-day
notice period and information about the date, place, and time of the
public hearing, as required under 40 CFR 51.102(a). After reasonable
notice, the public hearing was held virtually on March 16, 2023.\60\
Finally, Iowa's revised SIP submittal includes a certification that the
State satisfied the requirements in 40 CFR 51.102(a) and (d), as
required by 40 CFR 51.102(f).\61\
---------------------------------------------------------------------------
\59\ See Iowa August 15, 2023, submission at 66.
\60\ See 40 CFR 51.102(d).
\61\ See Iowa August 15, 2023, submission at 82.
---------------------------------------------------------------------------
Furthermore, in section 12.1 Response to Public Comments, Iowa
included additional details on the State's Notice of Nondiscrimination
and Language Access Plan that are publicly available on IDNR's website
and intended to provide meaningful access to individuals with limited
English proficiency.\62\ The EPA notes that the commenters do not
allege that IDNR failed to fulfill its public notice and comment
obligations, nor is there any indication that the commenters requested
language assistance. In this instance, the State's public comment
process meets the minimum requirements in the 40 CFR part 51, appendix
V for SIP submissions.
---------------------------------------------------------------------------
\62\ Id. at 76.
---------------------------------------------------------------------------
IV. What action is the EPA taking?
The EPA is taking final action to amend the Iowa SIP by approving
the State's submission received on August 15, 2023, as satisfying the
regional haze requirements for the second implementation period
contained in 40 CFR 51.308(f), (g), and (i). In addition, the EPA is
approving and incorporating by reference in 40 CFR 52.820(d), EPA-
Approved Iowa Source-Specific Orders/Permits the following source-
specific requirements as part of Iowa's long-term strategy for regional
haze:
<bullet> MidAmerican Energy Company--Louisa Station, permit #05-A-
031-P6, state effective date July 20, 2023, not including permit
condition 11.
<bullet> MidAmerican Energy Company--Walter Scott Jr. Energy
Center, permit #75-A-357-P9, state effective date July 20, 2023, not
including permit condition 11.
<bullet> MidAmerican Energy Company--Walter Scott, Jr. Energy
Center permit #03-A-425-P4, state effective date December 5, 2011, not
including permit condition 6.
V. Incorporation by Reference
In this document, the EPA is finalizing regulatory text that
includes incorporation by reference. In accordance with requirements of
1 CFR 51.5, the EPA is finalizing the incorporation by reference of the
Iowa permits #05-A-031-P6, #75-A-357-P9, and #03-A-425-P4 discussed in
sections I, II, and IV. of this preamble and as set forth below in the
amendments to 40 CFR part 52. The EPA has made, and will continue to
make, these materials generally available through <a href="https://www.regulations.gov">https://www.regulations.gov</a> and at the EPA Region 7 Office (please contact the
person identified in the FOR FURTHER INFORMATION CONTACT section of
this preamble for more information).
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 the final rulemaking of the
EPA's approval, and will be incorporated by reference in the next
update to the SIP compilation.\63\
---------------------------------------------------------------------------
\63\ 62 FR 27968, May 22, 1997.
---------------------------------------------------------------------------
VI. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely approves state law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by state
law. For that reason, this action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Orders 12866 (58
FR 51735, October 4, 1993);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions are exempt from review under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian Tribe has
demonstrated that a Tribe has jurisdiction. In those areas of Indian
country, the rule does not have Tribal implications and will not impose
substantial direct costs on Tribal
[[Page 37403]]
governments or preempt Tribal law as specified by Executive Order 13175
(65 FR 67249, November 9, 2000).
This action is subject to the Congressional Review Act (CRA), and
EPA will submit a rule report to each House of the Congress and to the
Comptroller General of the United States. This action is not a ``major
rule'' as defined by 5 U.S.C. 804(2).
Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by October 6, 2025. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this action 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, Nitrogen dioxide, Ozone, Particulate matter, Sulfur oxides.
Dated: July 31, 2025.
James Macy,
Regional Administrator, Region 7.
For the reasons stated in the preamble, the EPA amends Title 40,
chapter I, of the Code of Federal Regulations 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 Q-Iowa
0
2. In Sec. 52.820:
0
a. The table in paragraph (d) is amended by adding the entries
``(170)'', ``(171)'', and ``(172)'' in numerical order.
0
b. The table in paragraph (e) is amended by adding the entry ``(56)''
in numerical order.
The additions read as follows:
Sec. 52.820 Identification of plan.
* * * * *
(d) * * *
EPA-Approved Iowa Source-Specific Orders/Permits
----------------------------------------------------------------------------------------------------------------
Order/permit State
Name of source No. effective date EPA approval date Explanation
----------------------------------------------------------------------------------------------------------------
* * * * * * *
(170) MidAmerican Energy Company-- 05-A-031-P6 7/20/2023 8/5/25, 90 FR [insert Regional Haze Plan
Louisa Station. Federal Register for the second
page where the implementation
document begins]. period; condition 11
of the permit is not
part of the SIP.
(171) MidAmerican Energy Company-- 75-A-357-P9 7/20/2023 8/5/2025, 90 FR Regional Haze Plan
Walter Scott Jr. Energy Center. [insert Federal for the second
Register page where implementation
the document begins]. period; condition 11
of the permit is not
part of the SIP.
(172) MidAmerican Energy Company-- 03-A-425-P4 12/5/2011 8/5/2025, 90 FR Regional Haze Plan
Walter Scott, Jr. Energy Center. [insert Federal for the second
Register page where implementation
the document begins]. period; condition 6
of the permit is not
part of the SIP.
----------------------------------------------------------------------------------------------------------------
(e) * * *
EPA-Approved Iowa Nonregulatory Provisions
----------------------------------------------------------------------------------------------------------------
Applicable State
Name of nonregulatory SIP geographic or submittal EPA approval date Explanation
provision nonattainment area date
----------------------------------------------------------------------------------------------------------------
* * * * * * *
(56) Iowa Regional Haze Plan for Statewide........... 8/15/2023 8/5/25, 90 FR [EPA-R07-OAR-2024-03
the Second Implementation Period. [insert Federal 13; FRL-12096-02-
Register page where R7]
the document
begins].
----------------------------------------------------------------------------------------------------------------
0
3. Revise Sec. 52.842 to read as follows:
Sec. 52.842 Visibility protection.
(a) The requirements of section 169A of the Clean Air Act (CAA) are
met because the Regional Haze plan submitted by Iowa on March 25, 2008,
and supplemented on May 14, 2019, includes fully approvable measures
for meeting the requirements of the Regional Haze Rule including 40 CFR
51.308(d)(3) and (e) with respect to emissions of NO<INF>X</INF> and
SO<INF>2</INF> from electric generating units.
(b) The requirements of section 169A of the CAA are met because the
Regional Haze plan submitted by Iowa on August 15, 2023, includes fully
approvable measures for meeting the requirements of the Regional Haze
Rule in 40 CFR 51.308.
[FR Doc. 2025-14850 Filed 8-4-25; 8:45 am]
BILLING CODE 6560-50-P
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