Rule2024-09233

New Source Performance Standards for Greenhouse Gas Emissions From New, Modified, and Reconstructed Fossil Fuel-Fired Electric Generating Units; Emission Guidelines for Greenhouse Gas Emissions From Existing Fossil Fuel-Fired Electric Generating Units; and Repeal of the Affordable Clean Energy Rule

Primary source

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Published
May 9, 2024
Effective
July 8, 2024

Issuing agencies

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA) is finalizing multiple actions under section 111 of the Clean Air Act (CAA) addressing greenhouse gas (GHG) emissions from fossil fuel-fired electric generating units (EGUs). First, the EPA is finalizing the repeal of the Affordable Clean Energy (ACE) Rule. Second, the EPA is finalizing emission guidelines for GHG emissions from existing fossil fuel-fired steam generating EGUs, which include both coal-fired and oil/gas-fired steam generating EGUs. Third, the EPA is finalizing revisions to the New Source Performance Standards (NSPS) for GHG emissions from new and reconstructed fossil fuel-fired stationary combustion turbine EGUs. Fourth, the EPA is finalizing revisions to the NSPS for GHG emissions from fossil fuel-fired steam generating units that undertake a large modification, based upon the 8-year review required by the CAA. The EPA is not finalizing emission guidelines for GHG emissions from existing fossil fuel-fired stationary combustion turbines at this time; instead, the EPA intends to take further action on the proposed emission guidelines at a later date.

Full Text

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[Federal Register Volume 89, Number 91 (Thursday, May 9, 2024)]
[Rules and Regulations]
[Pages 39798-40064]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-09233]



[[Page 39797]]

Vol. 89

Thursday,

No. 91

May 9, 2024

Part III





Environmental Protection Agency





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40 CFR Part 60





New Source Performance Standards for Greenhouse Gas Emissions From New, 
Modified, and Reconstructed Fossil Fuel-Fired Electric Generating 
Units; Emission Guidelines for Greenhouse Gas Emissions From Existing 
Fossil Fuel-Fired Electric Generating Units; and Repeal of the 
Affordable Clean Energy Rule; Final Rule

Federal Register / Vol. 89 , No. 91 / Thursday, May 9, 2024 / Rules 
and Regulations

[[Page 39798]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2023-0072; FRL-8536-01-OAR]
RIN 2060-AV09


New Source Performance Standards for Greenhouse Gas Emissions 
From New, Modified, and Reconstructed Fossil Fuel-Fired Electric 
Generating Units; Emission Guidelines for Greenhouse Gas Emissions From 
Existing Fossil Fuel-Fired Electric Generating Units; and Repeal of the 
Affordable Clean Energy Rule

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is finalizing 
multiple actions under section 111 of the Clean Air Act (CAA) 
addressing greenhouse gas (GHG) emissions from fossil fuel-fired 
electric generating units (EGUs). First, the EPA is finalizing the 
repeal of the Affordable Clean Energy (ACE) Rule. Second, the EPA is 
finalizing emission guidelines for GHG emissions from existing fossil 
fuel-fired steam generating EGUs, which include both coal-fired and 
oil/gas-fired steam generating EGUs. Third, the EPA is finalizing 
revisions to the New Source Performance Standards (NSPS) for GHG 
emissions from new and reconstructed fossil fuel-fired stationary 
combustion turbine EGUs. Fourth, the EPA is finalizing revisions to the 
NSPS for GHG emissions from fossil fuel-fired steam generating units 
that undertake a large modification, based upon the 8-year review 
required by the CAA. The EPA is not finalizing emission guidelines for 
GHG emissions from existing fossil fuel-fired stationary combustion 
turbines at this time; instead, the EPA intends to take further action 
on the proposed emission guidelines at a later date.

DATES: This final rule is effective on July 8, 2024. The incorporation 
by reference of certain publications listed in the rules is approved by 
the Director of the Federal Register as of July 8, 2024. The 
incorporation by reference of certain other materials listed in the 
rule was approved by the Director of the Federal Register as of October 
23, 2015.

ADDRESSES: The EPA has established a docket for these actions under 
Docket ID No. EPA-HQ-OAR-2023-0072. All documents in the docket are 
listed on the <a href="https://www.regulations.gov">https://www.regulations.gov</a> website. Although listed, 
some information is not publicly available, e.g., 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 
electronically through <a href="https://www.regulations.gov">https://www.regulations.gov</a>.

FOR FURTHER INFORMATION CONTACT: Lisa Thompson (she/her), Sector 
Policies and Programs Division (D243-02), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, 109 T.W. 
Alexander Drive, P.O. Box 12055, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-5158; and email address: 
<a href="/cdn-cgi/l/email-protection#f4809c9b9984879b9ada989d8795b4918495da939b82"><span class="__cf_email__" data-cfemail="64100c0b0914170b0a4a080d1705240114054a030b12">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION: 
    Preamble acronyms and abbreviations. Throughout this document the 
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. The 
EPA uses multiple acronyms and terms in this preamble. While this list 
may not be exhaustive, to ease the reading of this preamble and for 
reference purposes, the EPA defines the following terms and acronyms 
here:

ACE Affordable Clean Energy rule
BSER best system of emissions reduction
Btu British thermal unit
CAA Clean Air Act
CBI Confidential Business Information
CCS carbon capture and sequestration/storage
CCUS carbon capture, utilization, and sequestration/storage
CO<INF>2</INF> carbon dioxide
DER distributed energy resources
DOE Department of Energy
EEA energy emergency alert
EGU electric generating unit
EIA Energy Information Administration
EJ environmental justice
E.O. Executive Order
EPA Environmental Protection Agency
FEED front-end engineering and design
FGD flue gas desulfurization
FR Federal Register
GHG greenhouse gas
GW gigawatt
GWh gigawatt-hour
HAP hazardous air pollutant
HRSG heat recovery steam generator
IIJA Infrastructure Investment and Jobs Act
IRC Internal Revenue Code
kg kilogram
kWh kilowatt-hour
LCOE levelized cost of electricity
LNG liquefied natural gas
MATS Mercury and Air Toxics Standards
MMBtu/h million British thermal units per hour
MMT CO<INF>2</INF>e million metric tons of carbon dioxide equivalent
MW megawatt
MWh megawatt-hour
NAAQS National Ambient Air Quality Standards
NESHAP National Emission Standards for Hazardous Air Pollutants
NGCC natural gas combined cycle
NO<INF>X</INF> nitrogen oxides
NSPS new source performance standards
NSR New Source Review
PM particulate matter
PM<INF>2.5</INF> fine particulate matter
RIA regulatory impact analysis
TSD technical support document
U.S. United States

    Organization of this document. The information in this preamble is 
organized as follows:

I. Executive Summary
    A. Climate Change and Fossil Fuel-Fired EGUs
    B. Recent Developments in Emissions Controls and the Electric 
Power Sector
    C. Summary of the Principal Provisions of These Regulatory 
Actions
    D. Grid Reliability Considerations
    E. Environmental Justice Considerations
    F. Energy Workers and Communities
    G. Key Changes From Proposal
II. General Information
    A. Action Applicability
    B. Where To Get a Copy of This Document and Other Related 
Information
III. Climate Change Impacts
IV. Recent Developments in Emissions Controls and the Electric Power 
Sector
    A. Background
    B. GHG Emissions From Fossil Fuel-Fired EGUs
    C. Recent Developments in Emissions Control
    D. The Electric Power Sector: Trends and Current Structure
    E. The Legislative, Market, and State Law Context
    F. Future Projections of Power Sector Trends
V. Statutory Background and Regulatory History for CAA Section 111
    A. Statutory Authority To Regulate GHGs From EGUs Under CAA 
Section 111
    B. History of EPA Regulation of Greenhouse Gases From 
Electricity Generating Units Under CAA Section 111 and Caselaw
    C. Detailed Discussion of CAA Section 111 Requirements

[[Page 39799]]

VI. ACE Rule Repeal
    A. Summary of Selected Features of the ACE Rule
    B. Developments Undermining ACE Rule's Projected Emission 
Reductions
    C. Developments Showing That Other Technologies Are the BSER for 
This Source Category
    D. Insufficiently Precise Degree of Emission Limitation 
Achievable From Application of the BSER
    E. Withdrawal of Proposed NSR Revisions
VII. Regulatory Approach for Existing Fossil Fuel-Fired Steam 
Generating Units
    A. Overview
    B. Applicability Requirements and Fossil Fuel-Type Definitions 
for Subcategories of Steam Generating Units
    C. Rationale for the BSER for Coal-Fired Steam Generating Units
    D. Rationale for the BSER for Natural Gas-Fired and Oil-Fired 
Steam Generating Units
    E. Additional Comments Received on the Emission Guidelines for 
Existing Steam Generating Units and Responses
    F. Regulatory Requirement To Review Emission Guidelines for 
Coal-Fired Units
VIII. Requirements for New and Reconstructed Stationary Combustion 
Turbine EGUs and Rationale for Requirements
    A. Overview
    B. Combustion Turbine Technology
    C. Overview of Regulation of Stationary Combustion Turbines for 
GHGs
    D. Eight-Year Review of NSPS
    E. Applicability Requirements and Subcategorization
    F. Determination of the Best System of Emission Reduction (BSER) 
for New and Reconstructed Stationary Combustion Turbines
    G. Standards of Performance
    H. Reconstructed Stationary Combustion Turbines
    I. Modified Stationary Combustion Turbines
    J. Startup, Shutdown, and Malfunction
    K. Testing and Monitoring Requirements
    L. Recordkeeping and Reporting Requirements
    M. Compliance Dates
    N. Compliance Date Extension
IX. Requirements for New, Modified, and Reconstructed Fossil Fuel-
Fired Steam Generating Units
    A. 2018 NSPS Proposal Withdrawal
    B. Additional Amendments
    C. Eight-Year Review of NSPS for Fossil Fuel-Fired Steam 
Generating Units
    D. Projects Under Development
X. State Plans for Emission Guidelines for Existing Fossil Fuel-
Fired EGUs
    A. Overview
    B. Requirement for State Plans To Maintain Stringency of the 
EPA's BSER Determination
    C. Establishing Standards of Performance
    D. Compliance Flexibilities
    E. State Plan Components and Submission
XI. Implications for Other CAA Programs
    A. New Source Review Program
    B. Title V Program
XII. Summary of Cost, Environmental, and Economic Impacts
    A. Air Quality Impacts
    B. Compliance Cost Impacts
    C. Economic and Energy Impacts
    D. Benefits
    E. Net Benefits
    F. Environmental Justice Analytical Considerations and 
Stakeholder Outreach and Engagement
    G. Grid Reliability Considerations and Reliability-Related 
Mechanisms
XIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act of 1995 (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks Populations and Low-
Income Populations
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations and Executive Order 14096: Revitalizing Our Nation's 
Commitment to Environmental Justice for All
    K. Congressional Review Act (CRA)
XIV. Statutory Authority

I. Executive Summary

    In 2009, the EPA concluded that GHG emissions endanger our nation's 
public health and welfare.\1\ Since that time, the evidence of the 
harms posed by GHG emissions has only grown, and Americans experience 
the destructive and worsening effects of climate change every day.\2\ 
Fossil fuel-fired EGUs are the nation's largest stationary source of 
GHG emissions, representing 25 percent of the United States' total GHG 
emissions in 2021.\3\ At the same time, a range of cost-effective 
technologies and approaches to reduce GHG emissions from these sources 
is available to the power sector--including carbon capture and 
sequestration/storage (CCS), co-firing with less GHG-intensive fuels, 
and more efficient generation. Congress has also acted to provide 
funding and other incentives to encourage the deployment of various 
technologies, including CCS, to achieve reductions in GHG emissions 
from the power sector.
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    \1\ 74 FR 66496 (December 15, 2009).
    \2\ The 5th National Climate Assessment (NCA5) states that the 
effects of human-caused climate change are already far-reaching and 
worsening across every region of the United States and that climate 
change affects all aspects of the energy system-supply, delivery, 
and demand-through the increased frequency, intensity, and duration 
of extreme events and through changing climate trends.
    \3\ <a href="https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions">https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions</a>.
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    In this notice, the EPA is finalizing several actions under section 
111 of the Clean Air Act (CAA) to reduce the significant quantity of 
GHG emissions from fossil fuel-fired EGUs by establishing emission 
guidelines and new source performance standards (NSPS) that are based 
on available and cost-effective technologies that directly reduce GHG 
emissions from these sources. Consistent with the statutory command of 
CAA section 111, the final NSPS and emission guidelines reflect the 
application of the best system of emission reduction (BSER) that, 
taking into account costs, energy requirements, and other statutory 
factors, is adequately demonstrated.
    Specifically, the EPA is first finalizing the repeal of the 
Affordable Clean Energy (ACE) Rule. Second, the EPA is finalizing 
emission guidelines for GHG emissions from existing fossil fuel-fired 
steam generating EGUs, which include both coal-fired and oil/gas-fired 
steam generating EGUs. Third, the EPA is finalizing revisions to the 
NSPS for GHG emissions from new and reconstructed fossil fuel-fired 
stationary combustion turbine EGUs. Fourth, the EPA is finalizing 
revisions to the NSPS for GHG emissions from fossil fuel-fired steam 
generating units that undertake a large modification, based upon the 8-
year review required by the CAA. The EPA is not finalizing emission 
guidelines for GHG emissions from existing fossil fuel-fired combustion 
turbines at this time and plans to expeditiously issue an additional 
proposal that more comprehensively addresses GHG emissions from this 
portion of the fleet. The EPA acknowledges that the share of GHG 
emissions from existing fossil fuel-fired combustion turbines has been 
growing and is projected to continue to do so, particularly as 
emissions from other portions of the fleet decline, and that it is 
vital to regulate the GHG emissions from these sources consistent with 
CAA section 111.
    These final actions ensure that the new and existing fossil fuel-
fired EGUs that are subject to these rules reduce their GHG emissions 
in a manner that is cost-effective and improves the emissions 
performance of the sources, consistent with the applicable CAA 
requirements and caselaw. These standards and emission guidelines will 
significantly decrease GHG emissions from fossil fuel-fired EGUs and 
the associated harms to human health and

[[Page 39800]]

welfare. Further, the EPA has designed these standards and emission 
guidelines in a way that is compatible with the nation's overall need 
for a reliable supply of affordable electricity.

A. Climate Change and Fossil Fuel-Fired EGUs

    These final actions reduce the emissions of GHGs from new and 
existing fossil fuel-fired EGUs. The increasing concentrations of GHGs 
in the atmosphere are, and have been, warming the planet, resulting in 
serious and life-threatening environmental and human health impacts. 
The increased concentrations of GHGs in the atmosphere and the 
resulting warming have led to more frequent and more intense heat waves 
and extreme weather events, rising sea levels, and retreating snow and 
ice, all of which are occurring at a pace and scale that threaten human 
health and welfare.
    Fossil fuel-fired EGUs that are uncontrolled for GHGs are one of 
the biggest domestic sources of GHG emissions. At the same time, there 
are technologies available (including technologies that can be applied 
to fossil fuel-fired power plants) to significantly reduce emissions of 
GHGs from the power sector. Low- and zero-GHG electricity are also key 
enabling technologies to significantly reduce GHG emissions in almost 
every other sector of the economy.
    In 2021, the power sector was the largest stationary source of GHGs 
in the United States, emitting 25 percent of overall domestic 
emissions.\4\ In 2021, existing fossil fuel-fired steam generating 
units accounted for 65 percent of the GHG emissions from the sector, 
but only accounted for 23 percent of the total electricity generation.
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    \4\ <a href="https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions">https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions</a>.
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    Because of its outsized contributions to overall emissions, 
reducing emissions from the power sector is essential to addressing the 
challenge of climate change--and sources in the power sector also have 
many available options for reducing their climate-destabilizing 
emissions. Particularly relevant to these actions are several key 
technologies (CCS and co-firing of lower-GHG fuels) that allow fossil 
fuel-fired steam generating EGUs and stationary combustion turbines to 
provide power while emitting significantly lower GHG emissions. 
Moreover, with the increased electrification of other GHG-emitting 
sectors of the economy, such as personal vehicles, heavy-duty trucks, 
and the heating and cooling of buildings, reducing GHG emissions from 
these affected sources can also help reduce power sector pollution that 
might otherwise result from the electrification of other sectors of the 
economy.

B. Recent Developments in Emissions Controls and the Electric Power 
Sector

    Several recent developments concerning emissions controls are 
relevant for the EPA's determination of the BSER for existing coal-
fired steam generating EGUs and new natural gas-fired stationary 
combustion turbines. These include lower costs and continued 
improvements in CCS technology, alongside Federal tax incentives that 
allow companies to largely offset the cost of CCS. Well-established 
trends in the sector further inform where using such technologies is 
cost effective and feasible, and form part of the basis for the EPA's 
determination of the BSER.
    In recent years, the cost of CCS has declined in part because of 
process improvements learned from earlier deployments and other 
advances in the technology. In addition, the Inflation Reduction Act 
(IRA), enacted in 2022, extended and significantly increased the tax 
credit for carbon dioxide (CO<INF>2</INF>) sequestration under Internal 
Revenue Code (IRC) section 45Q. The provision of tax credits in the 
IRA, combined with the funding included in the Infrastructure 
Investment and Jobs Act (IIJA), enacted in 2021, incentivize and 
facilitate the deployment of CCS and other GHG emission control 
technologies. As explained later in this preamble, these developments 
support the EPA's conclusion that CCS is the BSER for certain 
subcategories of new and existing EGUs because it is an adequately 
demonstrated and available control technology that significantly 
reduces emissions of dangerous pollution and because the costs of its 
installation and operation are reasonable. Some companies have already 
made plans to install CCS on their units independent of the EPA's 
regulations.
    Well documented trends in the power sector also influence the EPA's 
determination of the BSER. In particular, CCS entails significant 
capital expenditures and is only cost-reasonable for units that will 
operate enough to defray those capital costs. At the same time, many 
utilities and power generating companies have recently announced plans 
to accelerate changing the mix of their generating assets. The IIJA and 
IRA, state legislation, technology advancements, market forces, 
consumer demand, and the advanced age of much of the existing fossil 
fuel-fired generating fleet are collectively leading to, in most cases, 
decreased use of the fossil fuel-fired units that are the subjects of 
these final actions. From 2010 through 2022, fossil fuel-fired 
generation declined from approximately 72 percent of total net 
generation to approximately 60 percent, with generation from coal-fired 
sources dropping from 49 percent to 20 percent of net generation during 
this period.\5\ These trends are expected to continue and are relevant 
to determining where capital-intensive technologies, like CCS, may be 
feasibly and cost-reasonably deployed to reduce emissions.
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    \5\ U.S. Energy Information Administration (EIA). Electric Power 
Annual. 2010 and 2022. <a href="https://www.eia.gov/electricity/annual/html/epa_03_01_a.html">https://www.eia.gov/electricity/annual/html/epa_03_01_a.html</a>.
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    Congress has taken other recent actions to drive the reduction of 
GHG emissions from the power sector. As noted earlier, Congress enacted 
IRC section 45Q in section 115 of the Energy Improvement and Extension 
Act of 2008 to provide a tax credit for the sequestration of 
CO<INF>2</INF>. Congress significantly amended IRC section 45Q in the 
Bipartisan Budget Act of 2018, and more recently in the IRA, to make 
this tax incentive more generous and effective in spurring long-term 
deployment of CCS. In addition, the IIJA provided more than $65 billion 
for infrastructure investments and upgrades for transmission capacity, 
pipelines, and low-carbon fuels.\6\ Further, the Creating Helpful 
Incentives to Produce Semiconductors and Science Act (CHIPS Act) 
authorized billions more in funding for development of low- and non-GHG 
emitting energy technologies that could provide additional low-cost 
options for power companies to reduce overall GHG emissions.\7\ As 
discussed in greater detail in section IV.E.1 of this preamble, the 
IRA, the IIJA, and CHIPS contain numerous other provisions encouraging 
companies to reduce their GHGs.
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    \6\ <a href="https://www.congress.gov/bill/117th-congress/house-bill/3684">https://www.congress.gov/bill/117th-congress/house-bill/3684</a>.
    \7\ <a href="https://www.congress.gov/bill/117th-congress/house-bill/4346">https://www.congress.gov/bill/117th-congress/house-bill/4346</a>.
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C. Summary of the Principal Provisions of These Regulatory Actions

    These final actions include the repeal of the ACE Rule, BSER 
determinations and emission guidelines for existing fossil fuel-fired 
steam generating units, and BSER determinations and accompanying 
standards of performance for GHG emissions from new and reconstructed 
fossil fuel-fired stationary combustion turbines and modified fossil 
fuel-fired steam generating units.

[[Page 39801]]

    The EPA is taking these actions consistent with its authority under 
CAA section 111. Under CAA section 111, once the EPA has identified a 
source category that contributes significantly to dangerous air 
pollution, it proceeds to regulate new sources and, for GHGs and 
certain other air pollutants, existing sources. The central requirement 
is that the EPA must determine the ``best system of emission reduction 
. . . adequately demonstrated,'' taking into account the cost of the 
reductions, non-air quality health and environmental impacts, and 
energy requirements.\8\ The EPA may determine that different sets of 
sources have different characteristics relevant for determining the 
BSER and may subcategorize sources accordingly.
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    \8\ CAA section 111(a)(1).
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    Once it identifies the BSER, the EPA must determine the ``degree of 
emission limitation'' achievable by application of the BSER. For new 
sources, the EPA establishes the standard of performance with which the 
sources must comply, which is a standard for emissions that reflects 
the degree of emission limitation. For existing sources, the EPA 
includes the information it has developed concerning the BSER and 
associated degree of emission limitation in emission guidelines and 
directs the states to adopt state plans that contain standards of 
performance that are consistent with the emission guidelines.
    Since the early 1970s, the EPA has promulgated regulations under 
CAA section 111 for more than 60 source categories, which has 
established a robust set of regulatory precedents that has informed the 
development of these final actions. During this period, the courts, 
primarily the U.S. Court of Appeals for the D.C. Circuit and the 
Supreme Court, have developed a body of caselaw interpreting CAA 
section 111. As the Supreme Court has recognized, the EPA has typically 
(and does so in these actions) determined the BSER to be ``measures 
that improve the pollution performance of individual sources,'' such as 
add-on controls and clean fuels. West Virginia v. EPA, 597 U.S. 697, 
734 (2022). For present purposes, several of a BSER's key features 
include that it must reduce emissions, be based on ``adequately 
demonstrated'' technology, and have a reasonable cost of control. The 
case law interpreting section 111 has also recognized that the BSER can 
be forward-looking in nature and take into account anticipated 
improvements in control technologies. For example, the EPA may 
determine a control to be ``adequately demonstrated'' even if it is new 
and not yet in widespread commercial use, and, further, that the EPA 
may reasonably project the development of a control system at a future 
time and establish requirements that take effect at that time. Further, 
the most relevant costs under CAA section 111 are the costs to the 
regulated facility. The actions that the EPA is finalizing are 
consistent with the requirements of CAA section 111 and its regulatory 
history and caselaw, which is discussed in further detail in section V 
of this preamble.
1. Repeal of ACE Rule
    The EPA is finalizing its proposed repeal of the existing ACE Rule 
emission guidelines. First, as a policy matter, the EPA concludes that 
the suite of heat rate improvements (HRI) that was identified in the 
ACE Rule as the BSER is not an appropriate BSER for existing coal-fired 
EGUs. Second, the ACE Rule rejected CCS and natural gas co-firing as 
the BSER for reasons that no longer apply. Third, the EPA concludes 
that the ACE Rule conflicted with CAA section 111 and the EPA's 
implementing regulations because it did not provide sufficient 
specificity as to the BSER the EPA had identified or the ``degree of 
emission limitation achievable though application of the [BSER].''
    Also, the EPA is withdrawing the proposed revisions to the New 
Source Review (NSR) regulations that were included the ACE Rule 
proposal (83 FR 44773-83; August 31, 2018).
2. Emission Guidelines for Existing Fossil Fuel-Fired Steam Generating 
Units
    The EPA is finalizing CCS with 90 percent capture as BSER for 
existing coal-fired steam generating units. These units have a 
presumptive standard \9\ of an 88.4 percent reduction in annual 
emission rate, with a compliance deadline of January 1, 2032. As 
explained in detail below, CCS is an adequately demonstrated technology 
that achieves significant emissions reduction and is cost-reasonable, 
taking into account the declining costs of the technology and a 
substantial tax credit available to sources. In recognition of the 
significant capital expenditures involved in deploying CCS technology 
and the fact that 45 percent of regulated units already have announced 
retirement dates, the EPA is finalizing a separate subcategory for 
existing coal-fired steam generating units that demonstrate that they 
plan to permanently cease operation before January 1, 2039. The BSER 
for this subcategory is co-firing with natural gas, at a level of 40 
percent of the unit's annual heat input. These units have a presumptive 
standard of 16 percent reduction in annual emission rate corresponding 
to this BSER, with a compliance deadline of January 1, 2030.
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    \9\ Presumptive standards of performance are discussed in detail 
in section X of the preamble. While states establish standards of 
performance for sources, the EPA provides presumptively approvable 
standards of performance based on the degree of emission limitation 
achievable through application of the BSER for each subcategory.
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    The EPA is finalizing an applicability exemption for existing coal-
fired steam EGUs demonstrating that they plan to permanently cease 
operation prior to January 1, 2032, based on the Agency's determination 
that units retiring before this date generally do not have cost-
reasonable options for improving their GHG emissions performance. 
Sources that demonstrate they will permanently cease operation before 
this applicability deadline will not be subject to these emission 
guidelines. Further, the EPA is not finalizing the proposed imminent-
term or near-term subcategories.
    The EPA is finalizing the proposed structure of the subcategory 
definitions for natural gas- and oil-fired steam generating units. The 
EPA is also finalizing routine methods of operation and maintenance as 
the BSER for intermediate load and base load natural gas- and oil-fired 
steam generating units. Furthermore, the EPA is finalizing presumptive 
standards for natural gas- and oil-fired steam generating units that 
are slightly higher than at proposal: base load sources (those with 
annual capacity factors greater than 45 percent) have a presumptive 
standard of 1,400 lb CO<INF>2</INF>/MWh-gross, and intermediate load 
sources (those with annual capacity factors greater than 8 percent and 
less than or equal to 45 percent) have a presumptive standard of 1,600 
lb CO<INF>2</INF>/MWh-gross. For low load (those with annual capacity 
factors less than 8 percent), the EPA is finalizing a uniform fuels 
BSER and a presumptive input-based standard of 170 lb CO<INF>2</INF>/
MMBtu for oil-fired sources and a presumptive standard of 130 lb 
CO<INF>2</INF>/MMBtu for natural gas-fired sources.
3. Standards of Performance for New and Reconstructed Fossil Fuel-Fired 
Combustion Turbines
    The EPA is finalizing emission standards for three subcategories of 
combustion turbines--base load, intermediate load, and low load. The 
BSER for base load combustion turbines includes two components to be 
implemented initially in two phases. The first component of the BSER 
for base load combustion turbines is highly efficient generation (based 
on the emission rates that the best performing

[[Page 39802]]

units are achieving) and the second component for base load combustion 
turbines is utilization of CCS with 90 percent capture. Recognizing the 
lead time that is necessary for new base load combustion turbines to 
plan for and install the second component of the BSER (i.e., 90 percent 
CCS), including the time that is needed to deploy the associated 
infrastructure (CO<INF>2</INF> pipelines, storage sites, etc.), the EPA 
is finalizing a second phase compliance deadline of January 1, 2032, 
for this second component of the standard.
    The EPA has identified highly efficient simple cycle generation as 
the BSER for intermediate load combustion turbines. For low load 
combustion turbines, the EPA is finalizing its proposed determination 
that the BSER is the use of lower-emitting fuels.
4. New, Modified, and Reconstructed Fossil Fuel-Fired Steam Generating 
Units
    The EPA is finalizing revisions of the standards of performance for 
coal-fired steam generating units that undertake a large modification 
(i.e., a modification that increases its hourly emission rate by more 
than 10 percent) to mirror the emission guidelines for existing coal-
fired steam generators. This reflects the EPA's determination that such 
modified sources are capable of meeting the same presumptive standards 
that the EPA is finalizing for existing steam EGUs. Further, this 
revised standard for modified coal-fired steam EGUs will avoid creating 
an unjustified disparity between emission control obligations for 
modified and existing coal-fired steam EGUs.
    The EPA did not propose, and we are not finalizing, any review or 
revision of the 2015 standard for large modifications of oil- or gas-
fired steam generating units because we are not aware of any existing 
oil- or gas-fired steam generating EGUs that have undertaken such 
modifications or have plans to do so, and, unlike an existing coal-
fired steam generating EGUs, existing oil- or gas-fired steam units 
have no incentive to undertake such a modification to avoid the 
requirements we are including in this final rule for existing oil- or 
gas-fired steam generating units.
    As discussed in the proposal preamble, the EPA is not revising the 
NSPS for newly constructed or reconstructed fossil fuel-fired steam 
electric generating units (EGU) at this time because the EPA 
anticipates that few, if any, such units will be constructed or 
reconstructed in the foreseeable future. However, the EPA has recently 
become aware that a new coal-fired power plant is under consideration 
in Alaska. Accordingly, the EPA is not, at this time, finalizing its 
proposal not to review the 2015 NSPS, and, instead, will continue to 
consider whether to review the 2015 NSPS. As developments warrant, the 
EPA will determine either to conduct a review, and propose revised 
standards of performance, or not conduct a review.
    Also, in this final action, the EPA is withdrawing the 2018 
proposed amendments \10\ to the NSPS for GHG emissions from coal-fired 
EGUs.
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    \10\ See 83 FR 65424, December 20, 2018.
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5. Severability
    This final action is composed of four independent rules: the repeal 
of the ACE rule; GHG emission guidelines for existing fossil fuel-fired 
steam generating units; NSPS for GHG emissions from new and 
reconstructed fossil fuel-fired combustion turbines; and revisions to 
the standards of performance for new, modified, and reconstructed 
fossil fuel-fired steam generating units. The EPA could have finalized 
each of these rules in separate Federal Register notices as separate 
final actions. The Agency decided to include these four independent 
rules in a single Federal Register notice for administrative ease 
because they all relate to climate pollution from the fossil fuel-fired 
electric generating units source category. Accordingly, despite 
grouping these rules into one single Federal Register notice, the EPA 
intends that each of these rules described in sections I.C.1 through 
I.C.4 is severable from the other.
    In addition, each rule is severable as a practical matter. For 
example, the EPA would repeal the ACE Rule separate and apart from 
finalizing new standards for these sources as explained herein. 
Moreover, the BSER and associated emission guidelines for existing 
fossil fuel-fired steam generating units are independent of and would 
have been the same regardless of whether the EPA finalized the other 
parts of this rule. In determining the BSER for existing fossil fuel-
fired steam generating units, the EPA considered only the technologies 
available to reduce GHG emissions at those sources and did not take 
into consideration the technologies or standards of performance for new 
fossil fuel-fired combustion turbines. The same is true for the 
Agency's evaluation and determination of the BSER and associated 
standards of performance for new fossil fuel-fired combustion turbines. 
The EPA identified the BSER and established the standards of 
performance by examining the controls that were available for these 
units. That analysis can stand alone and apart from the EPA's separate 
analysis for existing fossil fuel-fired steam generating units. Though 
the record evidence (including, for example, modeling results) often 
addresses the availability, performance, and expected implementation of 
the technologies at both existing fossil fuel-fired steam generating 
units and new fossil fuel-fired combustion turbines in the same record 
documents, the evidence for each evaluation stands on its own, and is 
independently sufficient to support each of the final BSERs.
    In addition, within section I.C.1, the final action to repeal the 
ACE Rule is severable from the withdrawal of the NSR revisions that 
were proposed in parallel with the ACE Rule proposal. Within the group 
of actions for existing fossil fuel-fired steam generating units in 
section I.C.2, the requirements for each subcategory of existing 
sources are severable from the requirements for each other subcategory 
of existing sources. For example, if a court were to invalidate the 
BSER and associated emission standard for units in the medium-term 
subcategory, the BSER and associated emission standard for units in the 
long-term subcategory could function sensibly because the effectiveness 
of the BSER for each subcategory is not dependent on the effectiveness 
of the BSER for other subcategories. Within the group of actions for 
new and reconstructed fossil fuel-fired combustion turbines in section 
I.C.3, the following actions are severable: the requirements for each 
subcategory of new and reconstructed turbines are severable from the 
requirements for each other subcategory; and within the subcategory for 
base load turbines, the requirements for each of the two components are 
severable from the requirements for the other component. Each of these 
standards can function sensibly without the others. For example, the 
BSER for low load, intermediate load, and base load subcategories is 
based on the technologies the EPA determined met the statutory 
standards for those subcategories and are independent from each other. 
And in the base load subcategory units may practically be constructed 
using the most efficient technology without then installing CCS and 
likewise may install CCS on a turbine system that was not constructed 
with the most efficient technology. Within the group of actions for 
new, modified, and reconstructed fossil fuel-fired steam generating 
units in section I.C.4, the revisions of the standards of performance 
for coal-fired steam

[[Page 39803]]

generators that undertake a large modification are severable from the 
withdrawal of the 2018 proposal to revise the NSPS for emissions of GHG 
from EGUs. Each of the actions in these final rules that the EPA has 
identified as severable is functionally independent--i.e., may operate 
in practice independently of the other actions.
    In addition, while the EPA is finalizing this rule at the same time 
as other final rules regulating different types of pollution from 
EGUs--specifically the Supplemental Effluent Limitations Guidelines and 
Standards for the Steam Electric Power Generating Point Source Category 
(FR 2024-09815, EPA-HQ-OW-2009-0819; FRL-8794-02-OW); National Emission 
Standards for Hazardous Air Pollutants: Coal and Oil-Fired Electric 
Utility Steam Generating Units Review of the Residual Risk and 
Technology Review (FR 2024-09148, EPA-HQ-OAR-2018-0794; FRL-6716.3-02-
OAR); Hazardous and Solid Waste Management System: Disposal of Coal 
Combustion Residuals From Electric Utilities; Legacy CCR Surface 
Impoundments (FR 2024-09157, EPA-HQ-OLEM-2020-0107; FRL-7814-04-OLEM)--
and has considered the interactions between and cumulative effects of 
these rules, each rule is based on different statutory authority, a 
different record, and is completely independent of the other rules.

D. Grid Reliability Considerations

    The EPA is finalizing multiple adjustments to the proposed rules 
that ensure the requirements in these final actions can be implemented 
without compromising the ability of power companies, grid operators, 
and state and Federal energy regulators to maintain resource adequacy 
and grid reliability. In response to the May 2023 proposed rule, the 
EPA received extensive comments from balancing authorities, independent 
system operators and regional transmission organizations, state 
regulators, power companies, and other stakeholders on the need for the 
final rule to accommodate resource adequacy and grid reliability needs. 
The EPA also engaged with the balancing authorities that submitted 
comments to the docket, the staff and Commissioners of the Federal 
Energy Regulatory Commission (FERC), the Department of Energy (DOE), 
the North American Electric Reliability Corporation (NERC), and other 
expert entities during the course of this rulemaking. Finally, at the 
invitation of FERC, the EPA participated in FERC's Annual Reliability 
Technical Conference on November 9, 2023.
    These final actions respond to this input and feedback in multiple 
ways, including through changes to the universe of affected sources, 
longer compliance timeframes for CCS implementation, and other 
compliance flexibilities, as well as articulation of the appropriate 
use of RULOF to address reliability issues during state plan 
development and in subsequent state plan revisions. In addition to 
these adjustments, the EPA is finalizing several programmatic 
mechanisms specifically designed to address reliability concerns raised 
by commenters. For existing fossil fuel-fired EGUs, a short-term 
reliability emergency mechanism is available for states to provide more 
flexibility by using an alternative emission limitation during acute 
operational emergencies when the grid might be temporarily under heavy 
strain. A similar short-term reliability emergency mechanism is also 
available to new sources. In addition, the EPA is creating an option 
for states to provide for a compliance date extension for existing 
sources of up to 1 year under certain circumstances for sources that 
are installing control technologies to comply with their standards of 
performance. Lastly, states may also provide, by inclusion in their 
state plans, a reliability assurance mechanism of up to 1 year that 
under limited circumstances would allow existing units that had planned 
to cease operating by a certain date to temporarily remain available to 
support reliability. Any extensions exceeding 1 year must be addressed 
through a state plan revision. In order to utilize this reliability 
pathway, there must be an adequate demonstration of need and 
certification by a reliability authority, and approval by the 
appropriate EPA Regional Administrator. The EPA plans to seek the 
advice of FERC for extension requests exceeding 6 months. Similarly, 
for new fossil fuel-fired combustion turbines, the EPA is creating a 
mechanism whereby baseload units may request a 1-year extension of 
their CCS compliance deadline under certain circumstances.
    The EPA has evaluated the resource adequacy implications of these 
actions in the final technical support document (TSD), Resource 
Adequacy Analysis, and conducted capacity expansion modeling of the 
final rules in a manner that takes into account resource adequacy 
needs. The EPA finds that resource adequacy can be maintained with the 
final rules. The EPA modeled a scenario that complies with the final 
rules and that meets resource adequacy needs. The EPA also performed a 
variety of other sensitivity analyses looking at higher electricity 
demand (load growth) and impact of the EPA's additional regulatory 
actions affecting the power sector. These sensitivity analyses indicate 
that, in the context of higher demand and other pending power sector 
rules, the industry has available pathways to comply with this rule 
that respect NERC reliability considerations and constraints.
    In addition, the EPA notes that significant planning and regulatory 
mechanisms exist to ensure that sufficient generation resources are 
available to maintain reliability. The EPA's consideration of 
reliability in this rulemaking has also been informed by consultation 
with the DOE under the auspices of the March 9, 2023, memorandum of 
understanding (MOU) \11\ signed by the EPA Administrator and the 
Secretary of Energy, as well as by consultation with FERC expert staff. 
In these final actions, the EPA has included various flexibilities that 
allow power companies and grid operators to plan for achieving feasible 
and necessary reductions of GHGs from affected sources consistent with 
the EPA's statutory charge while ensuring that the rule will not 
interfere with systems operators' ability to ensure grid reliability.
---------------------------------------------------------------------------

    \11\ Joint Memorandum of Understanding on Interagency 
Communication and Consultation on Electric Reliability (March 9, 
2023). <a href="https://www.epa.gov/power-sector/electric-reliability-mou">https://www.epa.gov/power-sector/electric-reliability-mou</a>.
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    A thorough description of how adjustments in the final rules 
address reliability issues, the EPA's outreach to balancing 
authorities, EPA's supplemental notice, as well as the introduction of 
mechanisms to address short- and long-term reliability needs is 
presented in section XII.F of this preamble.

E. Environmental Justice Considerations

    Consistent with Executive Order (E.O.) 14096, and the EPA's 
commitment to upholding environmental justice (EJ) across its policies 
and programs, the EPA carefully considered the impacts of these actions 
on communities with environmental justice concerns. As part of the 
regulatory development process for these rulemakings, and consistent 
with directives set forth in multiple Executive Orders, the EPA 
conducted extensive outreach with interested parties including Tribal 
nations and communities with environmental justice concerns. These 
opportunities gave the EPA a chance to hear directly from the public, 
including from communities potentially impacted by these final

[[Page 39804]]

actions. The EPA took this feedback into account in its development of 
these final actions.\12\ The EPA's analysis of environmental justice in 
these final actions is briefly summarized here and discussed in further 
detail in sections XII.E and XIII.J of the preamble and section 6 of 
the regulatory impact analysis (RIA).
---------------------------------------------------------------------------

    \12\ Specifically, the EPA has relied on, and is incorporating 
as a basis for this rulemaking, analyses regarding possible adverse 
environmental effects from CCS, including those highlighted by 
commenters. Consideration of these effects is permissible under CAA 
section 111(a)(1). Although the EPA also conducted analyses of 
disproportionate impacts pursuant to E.O. 14096, see section XII.E, 
the EPA did not consider or rely on these analyses as a basis for 
these rules.
---------------------------------------------------------------------------

    Several environmental justice organizations and community 
representatives raised significant concerns about the potential health, 
environmental, and safety impacts of CCS. The EPA takes these concerns 
seriously, agrees that any impacts to historically disadvantaged and 
overburdened communities are important to consider, and has carefully 
considered these concerns as it finalized its determinations of the 
BSERs for these rules. The Agency acknowledges that while these final 
actions will result in large reductions of both GHGs and other 
emissions that will have significant positive benefits, there is the 
potential for localized increases in emissions, particularly if units 
installing CCS operate for more hours during the year and/or for more 
years than they would have otherwise. However, as discussed in section 
VII.C.1.a.iii(B), a robust regulatory framework exists to reduce the 
risks of localized emissions increases in a manner that is protective 
of public health, safety, and the environment. The Council on 
Environmental Quality's (CEQ) February 2022 Carbon Capture, 
Utilization, and Sequestration Guidance and the EPA's evaluation of 
BSER recognize that multiple Federal agencies have responsibility for 
regulating and permitting CCS projects, along with state and tribal 
governments. As the CEQ has noted, Federal agencies have ``taken 
actions in the past decade to develop a robust carbon capture, 
utilization, and sequestration/storage (CCUS) regulatory framework to 
protect the environment and public health across multiple statutes.'' 
\13\ \14\ Furthermore, the EPA plans to review and update as needed its 
guidance on NSR permitting, specifically with respect to BACT 
determinations for GHG emissions and consideration of co-pollutant 
increases from sources installing CCS. For the reasons explained in 
section VII.C, the EPA is finalizing the determination that CCS is the 
BSER for certain subcategories of new and existing EGUs based on its 
consideration of all of the statutory criteria for BSER, including 
emission reductions, cost, energy requirements, and non-air health and 
environmental considerations. At the same time, the EPA recognizes the 
critical importance of ensuring that the regulatory framework performs 
as intended to protect communities.
---------------------------------------------------------------------------

    \13\ 87 FR 8808, 8809 (February 16, 2022).
    \14\ This framework includes, among other things, the EPA 
regulation of geologic sequestration wells under the Underground 
Injection Control (UIC) program of the Safe Drinking Water Act; 
required reporting and public disclosure of geologic sequestration 
activity, as well as implementation of rigorous monitoring, 
reporting, and verification of geologic sequestration under the 
EPA's Greenhouse Gas Reporting Program (GHGRP); and safety 
regulations for CO<INF>2</INF> pipelines administered by the 
Pipeline and Hazardous Materials and Safety Administration (PHMSA).
---------------------------------------------------------------------------

    These actions are focused on establishing NSPS and emission 
guidelines for GHGs that states will implement to significantly reduce 
GHGs and move us a step closer to avoiding the worst impacts of climate 
change, which is already having a disproportionate impact on 
communities with environmental justice concerns. The EPA analyzed 
several illustrative scenarios representing potential compliance 
outcomes and evaluated the potential impacts that these actions may 
have on emissions of GHG and other health-harming air pollutants from 
fossil fuel-fired EGUs, as well as how these changes in emissions might 
affect air quality and public health, particularly for communities with 
EJ concerns.
    The EPA's national-level analysis of emission reduction and public 
health impacts, which is documented in section 6 of the RIA and 
summarized in greater detail in section XII.A and XII.D of this 
preamble, finds that these actions achieve nationwide reductions in EGU 
emissions of multiple health-harming air pollutants including nitrogen 
oxides (NO<INF>X</INF>), sulfur dioxide (SO<INF>2</INF>), and fine 
particulate matter (PM<INF>2.5</INF>), resulting in public health 
benefits. The EPA also evaluated how the air quality impacts associated 
with these final actions are distributed, with particular focus on 
communities with EJ concerns. As discussed in the RIA, our analysis 
indicates that baseline ozone and PM<INF>2.5</INF> concentration will 
decline substantially relative to today's levels. Relative to these low 
baseline levels, ozone and PM<INF>2.5</INF> concentrations will 
decrease further in virtually all areas of the country, although some 
areas of the country may experience slower or faster rates of decline 
in ozone and PM<INF>2.5</INF> pollution over time due to the changes in 
generation and utilization resulting from these rules. Additionally, 
our comparison of future air quality conditions with and without these 
rules suggests that while these actions are anticipated to lead to 
modest but widespread reductions in ambient levels of PM<INF>2.5</INF> 
and ozone for a large majority of the nation's population, there is 
potential for some geographic areas and demographic groups to 
experience small increases in ozone concentrations relative to the 
baseline levels which are projected to be substantially lower than 
today's levels.
    It is important to recognize that while these projections of 
emissions changes and resulting air quality changes under various 
illustrative compliance scenarios are based upon the best information 
available to the EPA at this time, with regard to existing sources, 
each state will ultimately be responsible for determining the future 
operation of fossil fuel-fired steam generating units located within 
its jurisdiction. The EPA expects that, in making these determinations, 
states will consider a number of factors and weigh input from the wide 
range of potentially affected stakeholders. The meaningful engagement 
requirements discussed in section X.E.1.b.i of this preamble will 
ensure that all interested stakeholders--including community members 
adversely impacted by pollution, energy workers affected by 
construction and/or other changes in operation at fossil-fuel-fired 
power plants, consumers and other interested parties--will have an 
opportunity to have their concerns heard as states make decisions 
balancing a multitude of factors including appropriate standards of 
performance, compliance strategies, and compliance flexibilities for 
existing EGUs, as well as public health and environmental 
considerations. The EPA believes that these provisions, together with 
the protections referenced above, can reduce the risks of localized 
emissions increases in a manner that is protective of public health, 
safety, and the environment.

F. Energy Workers and Communities

    These final actions include requirements for meaningful engagement 
in development of state plans, including with energy workers and 
communities. These communities, including energy workers employed at 
affected EGUs, workers who may construct and install pollution control 
technology, workers employed by fuel extraction and delivery, 
organizations

[[Page 39805]]

representing these workers, and communities living near affected EGUs, 
are impacted by power sector trends on an ongoing basis and by these 
final actions, and the EPA expects that states will include these 
stakeholders as part of their constructive engagement under the 
requirements in this rule.
    The EPA consulted with the Federal Interagency Working Group on 
Coal and Power Plant Communities and Economic Revitalization (Energy 
Communities IWG) in development of these rules and the meaningful 
engagement requirements. The EPA notes that the Energy Communities IWG 
has provided resources to help energy communities access the expanded 
federal resources made available by the Bipartisan Infrastructure Law, 
CHIPS and Science Act, and Inflation Reduction Act, many of which are 
relevant to the development of state plans.

G. Key Changes From Proposal

    The key changes from proposal in these final actions are: (1) the 
reduction in number of subcategories for existing coal-fired steam 
generating units, (2) the extension of the compliance date for existing 
coal-fired steam generating units to meet a standard of performance 
based on implementation of CCS, (3) the removal of low-GHG hydrogen co-
firing as a BSER pathway, and (4) the addition of two reliability-
related instruments. In addition, (5), the EPA is not finalizing 
proposed requirements for existing fossil fuel-fired stationary 
combustion turbines at this time.
    The reduction in number of subcategories for existing coal-fired 
steam generating units: The EPA proposed four subcategories for 
existing coal-fired steam generating units, which would have 
distinguished these units by operating horizon and by load level. These 
included subcategories for existing coal-fired EGUs planning to cease 
operations in the imminent-term (i.e., prior to January 1, 2032) and 
those planning to cease operations in the near-term (i.e., prior to 
January 1, 2035). While commenters were generally supportive of the 
proposed subcategorization approach, some requested that the cease-
operation-by date for the imminent-term subcategory be extended and the 
utilization limit for the near-term subcategory be relaxed. The EPA is 
not finalizing the imminent-term and near-term subcategories of coal-
fired steam generating units. Rather, the EPA is finalizing an 
applicability exemption for coal-fired steam generating units 
demonstrating that they plan to permanently cease operation before 
January 1, 2032. See section VII.B of this preamble for further 
discussion.
    The extension of the compliance date for existing coal-fired steam 
generating units to meet a standard of performance based on 
implementation of CCS. The EPA proposed a compliance date for 
implementation of CCS for long-term coal-fired steam generating units 
of January 1, 2030. The EPA received comments asserting that this 
deadline did not provide adequate lead time. In consideration of those 
comments, and the record as a whole, the EPA is finalizing a CCS 
compliance date of January 1, 2032 for these sources.
    The removal of low-GHG hydrogen co-firing as a BSER pathway and 
only use of low-GHG hydrogen as a compliance option: The EPA is not 
finalizing its proposed BSER pathway of low-GHG hydrogen co-firing for 
new and reconstructed base load and intermediate load combustion 
turbines in accordance with CAA section 111(a)(1). The EPA is also not 
finalizing its proposed requirement that only low-GHG hydrogen may be 
co-fired in a combustion turbine for the purpose of compliance with the 
standards of performance. These decisions are based on uncertainties 
identified for specific criteria used to evaluate low-GHG hydrogen co-
firing as a potential BSER, and after further analysis in response to 
public comments, the EPA has determined that these uncertainties 
prevent the EPA from concluding that low-GHG hydrogen co-firing is a 
component of the ``best'' system of emission reduction at this time. 
Under CAA section 111, the EPA establishes standards of performance but 
does not mandate use of any particular technology to meet those 
standards. Therefore, certain sources may elect to co-fire hydrogen for 
compliance with the final standards of performance, even absent the 
technology being a BSER pathway.\15\ See section VIII.F.5 of this 
preamble for further discussion.
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    \15\ The EPA is not placing qualifications on the type of 
hydrogen a source may elect to co-fire at this time (see section 
VIII.F.6.a of this preamble for further discussion). The Agency 
continues to recognize that even though the combustion of hydrogen 
is zero-GHG emitting, its production can entail a range of GHG 
emissions, from low to high, depending on the production method. 
Thus, even though the EPA is not finalizing the low-GHG hydrogen co-
firing as a BSER, as proposed, it maintains that the overall GHG 
profile of a particular method of hydrogen production should be a 
primary consideration for any source that decides to co-fire 
hydrogen to ensure that overall GHG reductions and important climate 
benefits are achieved. The EPA also notes the anticipated final rule 
from the U.S. Department of the Treasury pertaining to clean 
hydrogen production tax and energy credits, which in its proposed 
form contains certain eligibility parameters, as well as programs 
administered by the U.S. Department of Energy, such as the recent 
H2Hubs selections.
---------------------------------------------------------------------------

    The addition of two reliability-related instruments: Commenters 
expressed concerns that these rules, in combination with other factors, 
may affect the reliability of the bulk power system. In response to 
these comments the EPA engaged extensively with balancing authorities, 
power companies, reliability experts, and regulatory authorities 
responsible for reliability to inform its decisions in these final 
rules. As described later in this preamble, the EPA has made 
adjustments in these final rules that will support power companies, 
grid operators, and states in maintaining the reliability of the 
electric grid during the implementation of these final rules. In 
addition, the EPA has undertaken an analysis of the reliability and 
resource adequacy implications of these final rules that supports the 
Agency's conclusion that these final rules can be implemented without 
adverse consequences for grid reliability. Further, the EPA is 
finalizing two reliability-related instruments as an additional layer 
of safeguards for reliability. These instruments include a reliability 
mechanism for short-term emergency issues, and a reliability assurance 
mechanism, or compliance flexibility, for units that have chosen 
compliance pathways with enforceable retirement dates, provided there 
is a documented and verified reliability concern. In addition, the EPA 
is finalizing compliance extensions for unanticipated delays with 
control technology implementation. Specifically, as described in 
greater detail in section XII.F of this preamble, the EPA is finalizing 
the following features and changes from the proposal that will provide 
even greater certainty that these final rules are sensitive to 
reliability-related issues and constructed in a manner that does not 
interfere with grid operators' responsibility to deliver reliable 
power:
    (1) longer compliance timelines for existing coal-fired steam 
generating units;
    (2) a mechanism to extend compliance timelines by up to 1 year in 
the case of unforeseen circumstances, outside of an owner/operator's 
control, that delay the ability to apply controls (e.g., supply chain 
challenges or permitting delays);
    (3) transparent unit-specific compliance information for EGUs that 
will allow grid operators to plan for system changes with greater 
certainty and precision;
    (4) a short-term reliability mechanism to allow affected EGUs to 
operate at

[[Page 39806]]

baseline emission rates during documented reliability emergencies; and
    (5) a reliability assurance mechanism to allow states to delay 
cease operation dates by up to 1 year in cases where the planned cease 
operation date is forecast to disrupt system reliability.
    Not finalizing proposed requirements for existing fossil fuel-fired 
stationary combustion turbines at this time: The EPA proposed emission 
guidelines for large (i.e., greater than 300 MW), frequently operated 
(i.e., with an annual capacity factor of greater than 50 percent), 
existing fossil fuel-fired stationary combustion turbines. The EPA 
received a wide range of comments on the proposed guidelines. Multiple 
commenters suggested that the proposed provisions would largely result 
in shifting of generation away from the most efficient natural gas-
fired turbines to less efficient natural gas-fired turbines. Commenters 
stated that, as emissions from coal-fired steam generating units 
decreased, existing natural gas-fired EGUs were poised to become the 
largest source of GHG emissions in the power sector. Commenters noted 
that these units play an important role in grid reliability, 
particularly as aging coal-fired EGUs retire. Commenters further noted 
that the existing fossil fuel-fired stationary combustion turbines that 
were not covered by the proposal (i.e., the smaller and less frequently 
operating units) are often less efficient, less well controlled for 
other pollutants such as NO<INF>X</INF>, and are more likely to be 
located near population centers and communities with environmental 
justice concerns.
    The EPA agrees with commenters who observed that GHG emissions from 
existing natural gas-fired stationary combustion turbines are a growing 
portion of the emissions from the power sector. This is consistent with 
EPA modeling that shows that by 2030 these units will represent the 
largest portion of GHG emissions from the power sector. The EPA agrees 
that it is vital to promulgate emission guidelines to address GHG 
emissions from these sources, and that the EPA has a responsibility to 
do so under section 111(d) of the Clean Air Act. The EPA also agrees 
with commenters who noted that focusing only on the largest and most 
frequently operating units, without also addressing emissions from 
other units, as the May 2023 proposed rule provided, may not be the 
most effective way to address emissions from this sector. The EPA's 
modeling shows that over time as the power sector comes closer to 
reaching the phase-out threshold of the clean electricity incentives in 
the Inflation Reduction Act (IRA) (i.e., a 75 percent reduction in 
emissions from the power sector from 2022 levels), the average capacity 
factor for existing natural gas-fired stationary combustion turbines 
decreases. Therefore, the EPA's proposal to focus only on the largest 
units with the highest capacity factors may not be the most effective 
policy design for reducing GHG emissions from these sources.
    Recognizing the importance of reducing emissions from all fossil 
fuel-fired EGUs, the EPA is not finalizing the proposed emission 
guidelines for certain existing fossil fuel-fired stationary combustion 
turbines at this time. Instead, the EPA intends to issue a new, more 
comprehensive proposal to regulate GHGs from existing sources. The new 
proposal will focus on achieving greater emission reductions from 
existing stationary combustion turbines--which will soon be the largest 
stationary sources of GHG emissions--while taking into account other 
factors including the local non-GHG impacts of gas turbine generation 
and the need for reliable, affordable electricity.

II. General Information

A. Action Applicability

    The source category that is the subject of these actions is 
composed of fossil fuel-fired electric utility generating units. The 
North American Industry Classification System (NAICS) codes for the 
source category are 221112 and 921150. The list of categories and NAICS 
codes is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that these final actions are likely to 
affect.
    Final amendments to 40 CFR part 60, subpart TTTT, are directly 
applicable to affected facilities that began construction after January 
8, 2014, but before May 23, 2023, and affected facilities that began 
reconstruction or modification after June 18, 2014, but before May 23, 
2023. The NSPS codified in 40 CFR part 60, subpart TTTTa, is directly 
applicable to affected facilities that begin construction, 
reconstruction, or modification on or after May 23, 2023. Federal, 
state, local, and tribal government entities that own and/or operate 
EGUs subject to 40 CFR part 60, subpart TTTT or TTTTa, are affected by 
these amendments and standards.
    The emission guidelines codified in 40 CFR part 60, subpart UUUUb, 
are for states to follow in developing, submitting, and implementing 
state plans to establish performance standards to reduce emissions of 
GHGs from designated facilities that are existing sources. Section 
111(a)(6) of the CAA defines an ``existing source'' as ``any stationary 
source other than a new source.'' Therefore, the emission guidelines 
would not apply to any EGUs that are new after January 8, 2014, or 
reconstructed after June 18, 2014, the applicability dates of 40 CFR 
part 60, subpart TTTT. Under the Tribal Authority Rule (TAR), eligible 
tribes may seek approval to implement a plan under CAA section 111(d) 
in a manner similar to a state. See 40 CFR part 49, subpart A. Tribes 
may, but are not required to, seek approval for treatment in a manner 
similar to a state for purposes of developing a tribal implementation 
plan (TIP) implementing the emission guidelines codified in 40 CFR part 
60, subpart UUUUb. The TAR authorizes tribes to develop and implement 
their own air quality programs, or portions thereof, under the CAA. 
However, it does not require tribes to develop a CAA program. Tribes 
may implement programs that are most relevant to their air quality 
needs. If a tribe does not seek and obtain the authority from the EPA 
to establish a TIP, the EPA has the authority to establish a Federal 
CAA section 111(d) plan for designated facilities that are located in 
areas of Indian country.\16\ A Federal plan would apply to all 
designated facilities located in the areas of Indian country covered by 
the Federal plan unless and until the EPA approves a TIP applicable to 
those facilities.
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    \16\ See the EPA's website, <a href="https://www.epa.gov/tribal/tribes-approved-treatment-state-tas">https://www.epa.gov/tribal/tribes-approved-treatment-state-tas</a>, for information on those tribes that 
have treatment as a state for specific environmental regulatory 
programs, administrative functions, and grant programs.
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B. Where To Get a Copy of This Document and Other Related Information

    In addition to being available in the docket, an electronic copy of 
these final rulemakings is available on the internet at <a href="https://www.epa.gov/stationary-sources-air-pollution/greenhouse-gas-standards-and-guidelines-fossil-fuel-fired-power">https://www.epa.gov/stationary-sources-air-pollution/greenhouse-gas-standards-and-guidelines-fossil-fuel-fired-power</a>. Following signature by the EPA 
Administrator, the EPA will post a copy of these final rulemakings at 
this same website. Following publication in the Federal Register, the 
EPA will post the Federal Register version of the final rules and key 
technical documents at this same website.

C. Judicial Review and Administrative Review

    Under CAA section 307(b)(1), judicial review of these final actions 
is available only by filing a petition for review in

[[Page 39807]]

the United States Court of Appeals for the District of Columbia Circuit 
by July 8, 2024. These final actions are ``standard[s] of performance 
or requirement[s] under section 111,'' and, in addition, are 
``nationally applicable regulations promulgated, or final action taken, 
by the Administrator under [the CAA],'' CAA section 307(b)(1). Under 
CAA section 307(b)(2), the requirements established by this final rule 
may not be challenged separately in any civil or criminal proceedings 
brought by the EPA to enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that ``[o]nly an 
objection to a rule or procedure which was raised with reasonable 
specificity during the period for public comment (including any public 
hearing) may be raised during judicial review.'' This section also 
provides a mechanism for the EPA to convene a proceeding for 
reconsideration, ``[i]f the person raising an objection can demonstrate 
to the EPA that it was impracticable to raise such objection within 
[the period for public comment] or if the grounds for such objection 
arose after the period for public comment, (but within the time 
specified for judicial review) and if such objection is of central 
relevance to the outcome of the rule.'' Any person seeking to make such 
a demonstration to us should submit a Petition for Reconsideration to 
the Office of the Administrator, U.S. Environmental Protection Agency, 
Room 3000, WJC West Building, 1200 Pennsylvania Ave. NW, Washington, DC 
20460, with a copy to both the person(s) listed in the preceding FOR 
FURTHER INFORMATION CONTACT section, and the Associate General Counsel 
for the Air and Radiation Law Office, Office of General Counsel (Mail 
Code 2344A), U.S. Environmental Protection Agency, 1200 Pennsylvania 
Ave. NW, Washington, DC 20460.

III. Climate Change Impacts

    Elevated concentrations of GHGs have been warming the planet, 
leading to changes in the Earth's climate that are occurring at a pace 
and in a way that threatens human health, society, and the natural 
environment. While the EPA is not making any new scientific or factual 
findings with regard to the well-documented impact of GHG emissions on 
public health and welfare in support of these rules, the EPA is 
providing in this section a brief scientific background on climate 
change to offer additional context for these rulemakings and to help 
the public understand the environmental impacts of GHGs.
    Extensive information on climate change is available in the 
scientific assessments and the EPA documents that are briefly described 
in this section, as well as in the technical and scientific information 
supporting them. One of those documents is the EPA's 2009 
``Endangerment and Cause or Contribute Findings for Greenhouse Gases 
Under Section 202(a) of the CAA'' (74 FR 66496, December 15, 2009) 
(``2009 Endangerment Finding''). In the 2009 Endangerment Finding, the 
Administrator found under section 202(a) of the CAA that elevated 
atmospheric concentrations of six key well-mixed GHGs--CO<INF>2</INF>, 
methane (CH<INF>4</INF>), nitrous oxide (N<INF>2</INF>O), HFCs, 
perfluorocarbons (PFCs), and sulfur hexafluoride (SF<INF>6</INF>)--
``may reasonably be anticipated to endanger the public health and 
welfare of current and future generations'' (74 FR 66523, December 15, 
2009). The 2009 Endangerment Finding, together with the extensive 
scientific and technical evidence in the supporting record, documented 
that climate change caused by human emissions of GHGs threatens the 
public health of the U.S. population. It explained that by raising 
average temperatures, climate change increases the likelihood of heat 
waves, which are associated with increased deaths and illnesses (74 FR 
66497, December 15, 2009). While climate change also increases the 
likelihood of reductions in cold-related mortality, evidence indicates 
that the increases in heat mortality will be larger than the decreases 
in cold mortality in the U.S. (74 FR 66525, December 15, 2009). The 
2009 Endangerment Finding further explained that compared with a future 
without climate change, climate change is expected to increase 
tropospheric ozone pollution over broad areas of the U.S., including in 
the largest metropolitan areas with the worst tropospheric ozone 
problems, and thereby increase the risk of adverse effects on public 
health (74 FR 66525, December 15, 2009). Climate change is also 
expected to cause more intense hurricanes and more frequent and intense 
storms of other types and heavy precipitation, with impacts on other 
areas of public health, such as the potential for increased deaths, 
injuries, infectious and waterborne diseases, and stress-related 
disorders (74 FR 66525 December 15, 2009). Children, the elderly, and 
the poor are among the most vulnerable to these climate-related health 
effects (74 FR 66498, December 15, 2009).
    The 2009 Endangerment Finding also documented, together with the 
extensive scientific and technical evidence in the supporting record, 
that climate change touches nearly every aspect of public welfare \17\ 
in the U.S., including the following: changes in water supply and 
quality due to changes in drought and extreme rainfall events; 
increased risk of storm surge and flooding in coastal areas and land 
loss due to inundation; increases in peak electricity demand and risks 
to electricity infrastructure; and the potential for significant 
agricultural disruptions and crop failures (though offset to some 
extent by carbon fertilization). These impacts are also global and may 
exacerbate problems outside the U.S. that raise humanitarian, trade, 
and national security issues for the U.S. (74 FR 66530, December 15, 
2009).
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    \17\ The CAA states in section 302(h) that ``[a]ll language 
referring to effects on welfare includes, but is not limited to, 
effects on soils, water, crops, vegetation, manmade materials, 
animals, wildlife, weather, visibility, and climate, damage to and 
deterioration of property, and hazards to transportation, as well as 
effects on economic values and on personal comfort and well-being, 
whether caused by transformation, conversion, or combination with 
other air pollutants.'' 42 U.S.C. 7602(h).
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    In 2016, the Administrator issued a similar finding for GHG 
emissions from aircraft under section 231(a)(2)(A) of the CAA.\18\ In 
the 2016 Endangerment Finding, the Administrator found that the body of 
scientific evidence amassed in the record for the 2009 Endangerment 
Finding compellingly supported a similar endangerment finding under CAA 
section 231(a)(2)(A) and also found that the science assessments 
released between the 2009 and 2016 Findings ``strengthen and further 
support the judgment that GHGs in the atmosphere may reasonably be 
anticipated to endanger the public health and welfare of current and 
future generations'' (81 FR 54424, August 15, 2016).
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    \18\ Finding That Greenhouse Gas Emissions From Aircraft Cause 
or Contribute to Air Pollution That May Reasonably Be Anticipated To 
Endanger Public Health and Welfare. 81 FR 54422, August 15, 2016 
(``2016 Endangerment Finding'').
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    Since the 2016 Endangerment Finding, the climate has continued to 
change, with new observational records being set for several climate 
indicators such as global average surface temperatures, GHG 
concentrations, and sea level rise. Additionally, major scientific 
assessments continue to be released that further advance our 
understanding of the climate system and the impacts that GHGs have on 
public health and welfare for both current and future generations. 
These updated observations and projections document the rapid rate of 
current and future

[[Page 39808]]

climate change both globally and in the 
U.S.<SUP>19 20 21 22 23 24 25 26 27 28 29 30 31</SUP>
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    \19\ USGCRP, 2017: Climate Science Special Report: Fourth 
National Climate Assessment, Volume I [Wuebbles, D.J., D.W. Fahey, 
K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. 
U.S. Global Change Research Program, Washington, DC, USA, 470 pp, 
doi: 10.7930/J0J964J6.
    \20\ USGCRP, 2016: The Impacts of Climate Change on Human Health 
in the United States: A Scientific Assessment. Crimmins, A., J. 
Balbus, J.L. Gamble, C.B. Beard, J.E. Bell, D. Dodgen, R.J. Eisen, 
N. Fann, M.D. Hawkins, S.C. Herring, L. Jantarasami, D.M. Mills, S. 
Saha, M.C.
    \21\ USGCRP, 2018: Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, 1515 pp. doi:10.7930/NCA4.2018.
    \22\ IPCC, 2018: Global Warming of 1.5 [deg]C. An IPCC Special 
Report on the impacts of global warming of 1.5 [deg]C above pre-
industrial levels and related global greenhouse gas emission 
pathways, in the context of strengthening the global response to the 
threat of climate change, sustainable development, and efforts to 
eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. P[ouml]rtner, 
D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. 
P[eacute]an, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. 
Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. 
Waterfield (eds.)].
    \23\ IPCC, 2019: Climate Change and Land: an IPCC special report 
on climate change, desertification, land degradation, sustainable 
land management, food security, and greenhouse gas fluxes in 
terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. 
Masson-Delmotte, H.-O. P[ouml]rtner, D.C. Roberts, P. Zhai, R. 
Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. 
Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. 
Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)].
    \24\ IPCC, 2019: IPCC Special Report on the Ocean and Cryosphere 
in a Changing Climate [H.-O. P[ouml]rtner, D.C. Roberts, V. Masson-
Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. 
Alegri[iacute]a, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. 
Weyer (eds.)].
    \25\ National Academies of Sciences, Engineering, and Medicine. 
2016. Attribution of Extreme Weather Events in the Context of 
Climate Change. Washington, DC: The National Academies Press. 
<a href="https://dio.org/10.17226/21852">https://dio.org/10.17226/21852</a>.
    \26\ National Academies of Sciences, Engineering, and Medicine. 
2017. Valuing Climate Damages: Updating Estimation of the Social 
Cost of Carbon Dioxide. Washington, DC: The National Academies 
Press. <a href="https://doi.org/10.17226/24651">https://doi.org/10.17226/24651</a>.
    \27\ National Academies of Sciences, Engineering, and Medicine. 
2019. Climate Change and Ecosystems. Washington, DC: The National 
Academies Press. <a href="https://doi.org/10.17226/25504">https://doi.org/10.17226/25504</a>.
    \28\ Blunden, J. and T. Boyer, Eds., 2022: ``State of the 
Climate in 2021.'' Bull. Amer. Meteor. Soc., 103 (8), Si-S465, 
<a href="https://doi.org/10.1175/2022BAMSStateoftheClimate">https://doi.org/10.1175/2022BAMSStateoftheClimate</a>.1.
    \29\ U.S. Environmental Protection Agency. 2021. Climate Change 
and Social Vulnerability in the United States: A Focus on Six 
Impacts. EPA 430-R-21-003.
    \30\ Jay, A.K., A.R. Crimmins, C.W. Avery, T.A. Dahl, R.S. 
Dodder, B.D. Hamlington, A. Lustig, K. Marvel, P.A. M[eacute]ndez-
Lazaro, M.S. Osler, A. Terando, E.S. Weeks, and A. Zycherman, 2023: 
Ch. 1. Overview: Understanding risks, impacts, and responses. In: 
Fifth National Climate Assessment. Crimmins, A.R., C.W. Avery, D.R. 
Easterling, K.E. Kunkel, B.C. Stewart, and T.K. Maycock, Eds. U.S. 
Global Change Research Program, Washington, DC, USA. <a href="https://doi.org/10.7930/NCA5.2023.CH1">https://doi.org/10.7930/NCA5.2023.CH1</a>.
    \31\ IPCC, 2023: Summary for Policymakers. In: Climate Change 
2023: Synthesis Report. Contribution of Working Groups I, II and III 
to the Sixth Assessment Report of the Intergovernmental Panel on 
Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)].
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    The most recent information demonstrates that the climate is 
continuing to change in response to the human-induced buildup of GHGs 
in the atmosphere. These recent assessments show that atmospheric 
concentrations of GHGs have risen to a level that has no precedent in 
human history and that they continue to climb, primarily because of 
both historical and current anthropogenic emissions, and that these 
elevated concentrations endanger our health by affecting our food and 
water sources, the air we breathe, the weather we experience, and our 
interactions with the natural and built environments. For example, 
atmospheric concentrations of one of these GHGs, CO<INF>2</INF>, 
measured at Mauna Loa in Hawaii and at other sites around the world 
reached 419 parts per million (ppm) in 2022 (nearly 50 percent higher 
than preindustrial levels) \32\ and have continued to rise at a rapid 
rate. Global average temperature has increased by about 1.1 [deg]C (2.0 
[deg]F) in the 2011-2020 decade relative to 1850-1900.\33\ The years 
2015-2021 were the warmest 7 years in the 1880-2021 record, 
contributing to the warmest decade on record with a decadal temperature 
of 0.82 [deg]C (1.48 [deg]F) above the 20th century.\34\ \35\ The 
Intergovernmental Panel on Climate Change (IPCC) determined (with 
medium confidence) that this past decade was warmer than any multi-
century period in at least the past 100,000 years.\36\ Global average 
sea level has risen by about 8 inches (about 21 centimeters (cm)) from 
1901 to 2018, with the rate from 2006 to 2018 (0.15 inches/year or 3.7 
millimeters (mm)/year) almost twice the rate over the 1971 to 2006 
period, and three times the rate of the 1901 to 2018 period.\37\ The 
rate of sea level rise over the 20th century was higher than in any 
other century in at least the last 2,800 years.\38\ Higher 
CO<INF>2</INF> concentrations have led to acidification of the surface 
ocean in recent decades to an extent unusual in the past 65 million 
years, with negative impacts on marine organisms that use calcium 
carbonate to build shells or skeletons.\39\ Arctic sea ice extent 
continues to decline in all months of the year; the most rapid 
reductions occur in September (very likely almost a 13 percent decrease 
per decade between 1979 and 2018) and are unprecedented in at least 
1,000 years.\40\ Human-induced climate change has led to heatwaves and 
heavy precipitation becoming more frequent and more intense, along with 
increases in agricultural and ecological droughts \41\ in many 
regions.\42\
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    \32\ <a href="https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt">https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt</a>.
    \33\ IPCC, 2021: Summary for Policymakers. In: Climate Change 
2021: The Physical Science Basis. Contribution of Working Group I to 
the Sixth Assessment Report of the Intergovernmental Panel on 
Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. 
Connors, C. P[eacute]an, S. Berger, N. Caud, Y. Chen, L. Goldfarb, 
M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. 
Maycock, T. Waterfield, O. Yelek[ccedil]i, R. Yu, and B. Zhou 
(eds.)]. Cambridge University Press, Cambridge, United Kingdom and 
New York, NY, USA, pp. 3-32, doi:10.1017/9781009157896.001.
    \34\ NOAA National Centers for Environmental Information, State 
of the Climate 2021 retrieved on August 3, 2023, from <a href="https://www.ncei.noaa.gov/bams-state-of-climate">https://www.ncei.noaa.gov/bams-state-of-climate</a>.
    \35\ Blunden, J. and T. Boyer, Eds., 2022: ``State of the 
Climate in 2021.'' Bull. Amer. Meteor. Soc., 103 (8), Si-S465, 
https://doi.org/10.1175/2022BAMSStateoftheClimate1.
    \36\ IPCC, 2021.
    \37\ IPCC, 2021.
    \38\ USGCRP, 2018: Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, 1515 pp. doi:10.7930/NCA4.2018.
    \39\ IPCC, 2018.
    \40\ IPCC, 2021.
    \41\ These are drought measures based on soil moisture.
    \42\ IPCC, 2021.
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    The assessment literature demonstrates that modest additional 
amounts of warming may lead to a climate different from anything humans 
have ever experienced. The 2022 CO<INF>2</INF> concentration of 419 ppm 
is already higher than at any time in the last 2 million years.\43\ If 
concentrations exceed 450 ppm, they would likely be higher than any 
time in the past 23 million years: \44\ at the current rate of increase 
of more than 2 ppm per year, this would occur in about 15 years. While 
GHGs are not the only factor that controls climate, it is illustrative 
that 3 million years ago (the last time CO<INF>2</INF> concentrations 
were above 400 ppm) Greenland was not yet completely covered by ice and 
still supported forests, while 23 million years ago (the last time 
concentrations were above 450 ppm) the West Antarctic ice sheet was not 
yet developed, indicating the possibility that high GHG concentrations 
could lead to a world that looks very different from today and from the 
conditions in which human civilization has developed. If the Greenland 
and Antarctic ice sheets were

[[Page 39809]]

to melt substantially, sea levels would rise dramatically.
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    \43\ Annual Mauna Loa CO<INF>2</INF> concentration data from 
<a href="https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt">https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt</a>, 
accessed September 9, 2023.
    \44\ IPCC, 2013.
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    The NCA4 found that it is very likely (greater than 90 percent 
likelihood) that by mid-century, the Arctic Ocean will be almost 
entirely free of sea ice by late summer for the first time in about 2 
million years.\45\ Coral reefs will be at risk for almost complete (99 
percent) losses with 1 [deg]C (1.8 [deg]F) of additional warming from 
today (2 [deg]C or 3.6 [deg]F since preindustrial). At this 
temperature, between 8 and 18 percent of animal, plant, and insect 
species could lose over half of the geographic area with suitable 
climate for their survival, and 7 to 10 percent of rangeland livestock 
would be projected to be lost.\46\ The IPCC similarly found that 
climate change has caused substantial damages and increasingly 
irreversible losses in terrestrial, freshwater, and coastal and open 
ocean marine ecosystems.
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    \45\ USGCRP, 2018.
    \46\ IPCC, 2018.
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    Every additional increment of temperature comes with consequences. 
For example, the half degree of warming from 1.5 to 2 [deg]C (0.9 
[deg]F of warming from 2.7 [deg]F to 3.6 [deg]F) above preindustrial 
temperatures is projected on a global scale to expose 420 million more 
people to frequent extreme heatwaves at least every five years, and 62 
million more people to frequent exceptional heatwaves at least every 
five years (where heatwaves are defined based on a heat wave magnitude 
index which takes into account duration and intensity--using this 
index, the 2003 French heat wave that led to almost 15,000 deaths would 
be classified as an ``extreme heatwave'' and the 2010 Russian heatwave 
which led to thousands of deaths and extensive wildfires would be 
classified as ``exceptional''). It would increase the frequency of sea-
ice-free Arctic summers from once in 100 years to once in a decade. It 
could lead to 4 inches of additional sea level rise by the end of the 
century, exposing an additional 10 million people to risks of 
inundation as well as increasing the probability of triggering 
instabilities in either the Greenland or Antarctic ice sheets. Between 
half a million and a million additional square miles of permafrost 
would thaw over several centuries. Risks to food security would 
increase from medium to high for several lower-income regions in the 
Sahel, southern Africa, the Mediterranean, central Europe, and the 
Amazon. In addition to food security issues, this temperature increase 
would have implications for human health in terms of increasing ozone 
concentrations, heatwaves, and vector-borne diseases (for example, 
expanding the range of the mosquitoes which carry dengue fever, 
chikungunya, yellow fever, and the Zika virus or the ticks which carry 
Lyme, babesiosis, or Rocky Mountain Spotted Fever).\47\ Moreover, every 
additional increment in warming leads to larger changes in extremes, 
including the potential for events unprecedented in the observational 
record. Every additional degree will intensify extreme precipitation 
events by about 7 percent. The peak winds of the most intense tropical 
cyclones (hurricanes) are projected to increase with warming. In 
addition to a higher intensity, the IPCC found that precipitation and 
frequency of rapid intensification of these storms has already 
increased, the movement speed has decreased, and elevated sea levels 
have increased coastal flooding, all of which make these tropical 
cyclones more damaging.\48\
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    \47\ IPCC, 2018.
    \48\ IPCC, 2021.
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    The NCA4 also evaluated a number of impacts specific to the U.S. 
Severe drought and outbreaks of insects like the mountain pine beetle 
have killed hundreds of millions of trees in the western U.S. Wildfires 
have burned more than 3.7 million acres in 14 of the 17 years between 
2000 and 2016, and Federal wildfire suppression costs were about a 
billion dollars annually.\49\ The National Interagency Fire Center has 
documented U.S. wildfires since 1983, and the 10 years with the largest 
acreage burned have all occurred since 2004.\50\ Wildfire smoke 
degrades air quality, increasing health risks, and more frequent and 
severe wildfires due to climate change would further diminish air 
quality, increase incidences of respiratory illness, impair visibility, 
and disrupt outdoor activities, sometimes thousands of miles from the 
location of the fire. Meanwhile, sea level rise has amplified coastal 
flooding and erosion impacts, requiring the installation of costly pump 
stations, flooding streets, and increasing storm surge damages. Tens of 
billions of dollars of U.S. real estate could be below sea level by 
2050 under some scenarios. Increased frequency and duration of drought 
will reduce agricultural productivity in some regions, accelerate 
depletion of water supplies for irrigation, and expand the distribution 
and incidence of pests and diseases for crops and livestock. The NCA4 
also recognized that climate change can increase risks to national 
security, both through direct impacts on military infrastructure and by 
affecting factors such as food and water availability that can 
exacerbate conflict outside U.S. borders. Droughts, floods, storm 
surges, wildfires, and other extreme events stress nations and people 
through loss of life, displacement of populations, and impacts on 
livelihoods.\51\ The NCA5 further reinforces the science showing that 
climate change will have many impacts on the U.S., as described above 
in the preamble. Particularly relevant for these rules, the NCA5 states 
that climate change affects all aspects of the energy system-supply, 
delivery, and demand-through the increased frequency, intensity, and 
duration of extreme events and through changing climate trends.'' \52\
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    \49\ USGCRP, 2018.
    \50\ NIFC (National Interagency Fire Center). 2021. Total 
wildland fires and acres (1983-2020). Accessed August 2021. <a href="https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html">https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html</a>.
    \51\ USGCRP, 2018.
    \52\ Jay, A.K., A.R. Crimmins, C.W. Avery, T.A. Dahl, R.S. 
Dodder, B.D. Hamlington, A. Lustig, K. Marvel, P.A. M[eacute]ndez-
Lazaro, M.S. Osler, A. Terando, E.S. Weeks, and A. Zycherman, 2023: 
Ch. 1. Overview: Understanding risks, impacts, and responses. In: 
Fifth National Climate Assessment. Crimmins, A.R., C.W. Avery, D.R. 
Easterling, K.E. Kunkel, B.C. Stewart, and T.K. Maycock, Eds. U.S. 
Global Change Research Program, Washington, DC, USA. <a href="https://doi.org/10.7930/NCA5.2023.CH1">https://doi.org/10.7930/NCA5.2023.CH1</a>.
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    EPA modeling efforts can further illustrate how these impacts from 
climate change may be experienced across the U.S. EPA's Framework for 
Evaluating Damages and Impacts (FrEDI) \53\ uses information from over 
30 peer-reviewed climate change impact studies to project the physical 
and economic impacts of climate change to the U.S. resulting from 
future temperature changes. These impacts are projected for specific 
regions within the U.S. and for more than 20 impact categories, which 
span a large number of sectors of the U.S. economy.\54\ Using

[[Page 39810]]

this framework, the EPA estimates that global emission projections, 
with no additional mitigation, will result in significant climate-
related damages to the U.S.\55\ These damages to the U.S. would mainly 
be from increases in lives lost due to increases in temperatures, as 
well as impacts to human health from increases in climate-driven 
changes in air quality, dust and wildfire smoke exposure, and incidence 
of suicide. Additional major climate-related damages would occur to 
U.S. infrastructure such as roads and rail, as well as transportation 
impacts and coastal flooding from sea level rise, increases in property 
damage from tropical cyclones, and reductions in labor hours worked in 
outdoor settings and buildings without air conditioning. These impacts 
are also projected to vary from region to region with the Southeast, 
for example, projected to see some of the largest damages from sea 
level rise, the West Coast projected to experience damages from 
wildfire smoke more than other parts of the country, and the Northern 
Plains states projected to see a higher proportion of damages to rail 
and road infrastructure. While information on the distribution of 
climate impacts helps to better understand the ways in which climate 
change may impact the U.S., recent analyses are still only a partial 
assessment of climate impacts relevant to U.S. interests and in 
addition do not reflect increased damages that occur due to 
interactions between different sectors impacted by climate change or 
all the ways in which physical impacts of climate change occurring 
abroad have spillover effects in different regions of the U.S.
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    \53\ (1) Hartin, C., et al. (2023). Advancing the estimation of 
future climate impacts within the United States. Earth Syst. Dynam., 
14, 1015-1037, <a href="https://doi.org/10.5194/esd-14-1015-2023">https://doi.org/10.5194/esd-14-1015-2023</a>. (2) 
Supplementary Material for the Regulatory Impact Analysis for the 
Final Rulemaking, Standards of Performance for New, Reconstructed, 
and Modified Sources and Emissions Guidelines for Existing Sources: 
Oil and Natural Gas Sector Climate Review, ``Report on the Social 
Cost of Greenhouse Gases: Estimates Incorporating Recent Scientific 
Advances,'' Docket ID No. EPA-HQ-OAR-2021-0317, November 2023, (3) 
The Long-Term Strategy of the United States: Pathways to Net-Zero 
Greenhouse Gas Emissions by 2050. Published by the U.S. Department 
of State and the U.S. Executive Office of the President, Washington 
DC. November 2021, (4) Climate Risk Exposure: An Assessment of the 
Federal Government's Financial Risks to Climate Change, White Paper, 
Office of Management and Budget, April 2022.
    \54\ EPA (2021). Technical Documentation on the Framework for 
Evaluating Damages and Impacts (FrEDI). U.S. Environmental 
Protection Agency, EPA 430-R-21-004, <a href="https://www.epa.gov/cira/fredi">https://www.epa.gov/cira/fredi</a>. 
Documentation has been subject to both a public review comment 
period and an independent expert peer review, following EPA peer-
review guidelines.
    \55\ Compared to a world with no additional warming after the 
model baseline (1986-2005).
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    Some GHGs also have impacts beyond those mediated through climate 
change. For example, elevated concentrations of CO<INF>2</INF> 
stimulate plant growth (which can be positive in the case of beneficial 
species, but negative in terms of weeds and invasive species, and can 
also lead to a reduction in plant micronutrients \56\) and cause ocean 
acidification. Nitrous oxide depletes the levels of protective 
stratospheric ozone.\57\ Methane reacts to form tropospheric ozone.
---------------------------------------------------------------------------

    \56\ Ziska, L., A. Crimmins, A. Auclair, S. DeGrasse, J.F. 
Garofalo, A.S. Khan, I. Loladze, A.A. P[eacute]rez de Le[oacute]n, 
A. Showler, J. Thurston, and I. Walls, 2016: Ch. 7: Food Safety, 
Nutrition, and Distribution. The Impacts of Climate Change on Human 
Health in the United States: A Scientific Assessment. U.S. Global 
Change Research Program, Washington, DC, 189-216. <a href="https://health2016.globalchange.gov/low/ClimateHealth2016_07_Food_small.pdf">https://health2016.globalchange.gov/low/ClimateHealth2016_07_Food_small.pdf</a>.
    \57\ WMO (World Meteorological Organization), Scientific 
Assessment of Ozone Depletion: 2018, Global Ozone Research and 
Monitoring Project--Report No. 58, 588 pp., Geneva, Switzerland, 
2018.
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    Section XII.E of this preamble discusses the impacts of GHG 
emissions on individuals living in socially and economically vulnerable 
communities. While the EPA did not conduct modeling to specifically 
quantify changes in climate impacts resulting from these rules in terms 
of avoided temperature change or sea-level rise, the Agency did 
quantify climate benefits by monetizing the emission reductions through 
the application of the social cost of greenhouse gases (SC-GHGs), as 
described in section XII.D of this preamble.
    These scientific assessments, the EPA analyses, and documented 
observed changes in the climate of the planet and of the U.S. present 
clear support regarding the current and future dangers of climate 
change and the importance of GHG emissions mitigation.

IV. Recent Developments in Emissions Controls and the Electric Power 
Sector

    In this section, we discuss background information about the 
electric power sector and controls available to limit GHG pollution 
from the fossil fuel-fired power plants regulated by these final rules, 
and then discuss several recent developments that are relevant for 
determining the BSER for these sources. After giving some general 
background, we first discuss CCS and explain that its costs have fallen 
significantly. Lower costs are central for the EPA's determination that 
CCS is the BSER for certain existing coal-fired steam generating units 
and certain new natural gas-fired combustion turbines. Second, we 
discuss natural gas co-firing for coal-fired steam generating units and 
explain recent reductions in cost for this approach as well as its 
widespread availability and current and potential deployment within 
this subcategory. Third, we discuss highly efficient generation as a 
BSER technology for new and reconstructed simple cycle and combined 
cycle combustion turbine EGUs. The emission reductions achieved by 
highly efficient turbines are well demonstrated in the power sector, 
and along with operational and maintenance best practices, represent a 
cost-effective technology that reduces fuel consumption. Finally, we 
discuss key developments in the electric power sector that influence 
which units can feasibly and cost-effectively deploy these 
technologies.

A. Background

1. Electric Power Sector
    Electricity in the U.S. is generated by a range of technologies, 
and different EGUs play different roles in providing reliable and 
affordable electricity. For example, certain EGUs generate base load 
power, which is the portion of electricity loads that are continually 
present and typically operate throughout all hours of the year. 
Intermediate EGUs often provide complementary generation to balance 
variable supply and demand resources. Low load ``peaking units'' 
provide capacity during hours of the highest daily, weekly, or seasonal 
net demand, and while these resources have low levels of utilization on 
an annual basis, they play important roles in providing generation to 
meet short-term demand and often must be available to quickly increase 
or decrease their output. Furthermore, many of these EGUs also play 
important roles ensuring the reliability of the electric grid, 
including facilitating the regulation of frequency and voltage, 
providing ``black start'' capability in the event the grid must be 
repowered after a widespread outage, and providing reserve generating 
capacity \58\ in the event of unexpected changes in the availability of 
other generators.
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    \58\ Generation and capacity are commonly reported statistics 
with key distinctions. Generation is the production of electricity 
and is a measure of an EGU's actual output while capacity is a 
measure of the maximum potential production of an EGU under certain 
conditions. There are several methods to calculate an EGU's 
capacity, which are suited for different applications of the 
statistic. Capacity is typically measured in megawatts (MW) for 
individual units or gigawatts (1 GW = 1,000 MW) for multiple EGUs. 
Generation is often measured in kilowatt-hours (1 kWh = 1,000 watt-
hours), megawatt-hours (1 MWh = 1,000 kWh), gigawatt-hours (1 GWh = 
1 million kWh), or terawatt-hours (1 TWh = 1 billion kWh).
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    In general, the EGUs with the lowest operating costs are dispatched 
first, and, as a result, an inefficient EGU with high fuel costs will 
typically only operate if other lower-cost plants are unavailable or 
are insufficient to meet demand. Units are also unavailable during both 
routine and unanticipated outages, which typically become more frequent 
as power plants age. These factors result in the mix of available 
generating capacity types (e.g., the share of capacity of each type of 
generating source) being substantially different than the mix of the 
share of total electricity produced by each type of generating source 
in a given season or year.

[[Page 39811]]

    Generated electricity must be transmitted over networks \59\ of 
high voltage lines to substations where power is stepped down to a 
lower voltage for local distribution. Within each of these transmission 
networks, there are multiple areas where the operation of power plants 
is monitored and controlled by regional organizations to ensure that 
electricity generation and load are kept in balance. In some areas, the 
operation of the transmission system is under the control of a single 
regional operator; \60\ in others, individual utilities \61\ coordinate 
the operations of their generation and transmission to balance the 
system across their respective service territories.
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    \59\ The three network interconnections are the Western 
Interconnection, comprising the western parts of the U.S. and 
Canada, the Eastern Interconnection, comprising the eastern parts of 
the U.S. and Canada except parts of Eastern Canada in the Quebec 
Interconnection, and the Texas Interconnection, encompassing the 
portion of the Texas electricity system commonly known as the 
Electric Reliability Council of Texas (ERCOT). See map of all NERC 
interconnections at <a href="https://www.nerc.com/AboutNERC/keyplayers/PublishingImages/NERC%20Interconnections.pdf">https://www.nerc.com/AboutNERC/keyplayers/PublishingImages/NERC%20Interconnections.pdf</a>.
    \60\ For example, PJM Interconnection, LLC, New York Independent 
System Operator (NYISO), Midwest Independent System Operator (MISO), 
California Independent System Operator (CAISO), etc.
    \61\ For example, Los Angeles Department of Power and Water, 
Florida Power and Light, etc.
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2. Types of EGUs
    There are many types of EGUs including fossil fuel-fired power 
plants (i.e., those using coal, oil, and natural gas), nuclear power 
plants, renewable generating sources (such as wind and solar) and 
others. This rule focuses on the fossil fuel-fired portion of the 
generating fleet that is responsible for the vast majority of GHG 
emissions from the power sector. The definition of fossil fuel-fired 
electric utility steam generating units includes utility boilers as 
well as those that use gasification technology (i.e., integrated 
gasification combined cycle (IGCC) units). While coal is the most 
common fuel for fossil fuel-fired utility boilers, natural gas can also 
be used as a fuel in these EGUs and many existing coal- and oil-fired 
utility boilers have refueled as natural gas-fired utility boilers. An 
IGCC unit gasifies fuel--typically coal or petroleum coke--to form a 
synthetic gas (or syngas) composed of carbon monoxide (CO) and hydrogen 
(H<INF>2</INF>), which can be combusted in a combined cycle system to 
generate power. The heat created by these technologies produces high-
pressure steam that is released to rotate turbines, which, in turn, 
spin an electric generator.
    Stationary combustion turbine EGUs (most commonly natural gas-
fired) use one of two configurations: combined cycle or simple cycle 
turbines. Combined cycle units have two generating components (i.e., 
two cycles) operating from a single source of heat. Combined cycle 
units first generate power from a combustion turbine (i.e., the 
combustion cycle) directly from the heat of burning natural gas or 
other fuel. The second cycle reuses the waste heat from the combustion 
turbine engine, which is routed to a heat recovery steam generator 
(HRSG) that generates steam, which is then used to produce additional 
power using a steam turbine (i.e., the steam cycle). Combining these 
generation cycles increases the overall efficiency of the system. 
Combined cycle units that fire mostly natural gas are commonly referred 
to as natural gas combined cycle (NGCC) units, and, with greater 
efficiency, are utilized at higher capacity factors to provide base 
load or intermediate load power. An EGU's capacity factor indicates a 
power plant's electricity output as a percentage of its total 
generation capacity. Simple cycle turbines only use a combustion 
turbine to produce electricity (i.e., there is no heat recovery or 
steam cycle). These less-efficient combustion turbines are generally 
utilized at non-base load capacity factors and contribute to reliable 
operations of the grid during periods of peak demand or provide 
flexibility to support increased generation from variable energy 
sources.\62\
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    \62\ Non-dispatchable renewable energy (electrical output cannot 
be used at any given time to meet fluctuating demand) is both 
variable and intermittent and is often referred to as intermittent 
renewable energy. The variability aspect results from predictable 
changes in electric generation (e.g., solar not generating 
electricity at night) that often occur on longer time periods. The 
intermittent aspect of renewable energy results from inconsistent 
generation due to unpredictable external factors outside the control 
of the owner/operator (e.g., imperfect local weather forecasts) that 
often occur on shorter time periods. Since renewable energy 
fluctuates over multiple time periods, grid operators are required 
to adjust forecast and real time operating procedures. As more 
renewable energy is added to the electric grid and generation 
forecasts improve, the intermittency of renewable energy is reduced.
---------------------------------------------------------------------------

    Other generating sources produce electricity by harnessing kinetic 
energy from flowing water, wind, or tides, thermal energy from 
geothermal wells, or solar energy primarily through photovoltaic solar 
arrays. Spurred by a combination of declining costs, consumer 
preferences, and government policies, the capacity of these renewable 
technologies is growing, and when considered with existing nuclear 
energy, accounted for 40 percent of the overall net electricity supply 
in 2022. Many projections show this share growing over time. For 
example, the EPA's Power Sector Platform 2023 using IPM (i.e., the 
EPA's baseline projections of the power sector) projects zero-emitting 
sources reaching 76 percent of electricity generation by 2040. This 
shift is driven by multiple factors. These factors include changes in 
the relative economics of generating technologies, the efforts by 
states to reduce GHG emissions, utility and other corporate 
commitments, and customer preference. The shift is further promoted by 
provisions of Federal legislation, most notably the Clean Electricity 
Investment and Production tax credits included in IRC sections 48E and 
45Y of the IRA, which do not begin to phase out until the later of 2032 
or when power sector GHG emissions are 75 percent less than 2022 
levels. (See section IV.F of this preamble and the accompanying RIA for 
additional discussion of projections for the power sector.) These 
projections are consistent with power company announcements. For 
example, as the Edison Electric Institute (EEI) stated in pre-proposal 
public comments submitted to the regulatory docket: ``Fifty EEI members 
have announced forward-looking carbon reduction goals, two-thirds of 
which include a net-zero by 2050 or earlier equivalent goal, and 
members are routinely increasing the ambition or speed of their goals 
or altogether transforming them into net-zero goals . . . . EEI's 
member companies see a clear path to continued emissions reductions 
over the next decade using current technologies, including nuclear 
power, natural gas-based generation, energy demand efficiency, energy 
storage, and deployment of new renewable energy--especially wind and 
solar--as older coal-based and less-efficient natural gas-based 
generating units retire.'' \63\ The Energy Strategy Coalition similarly 
said in public comments that ``[a]s major electrical utilities and 
power producers, our top priority is providing clean, affordable, and 
reliable energy to our customers'' and are ``seeking to advance'' 
technologies ``such as a carbon capture and storage, which can 
significantly reduce carbon dioxide

[[Page 39812]]

emissions from fossil fuel-fired EGUs.'' \64\
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    \63\ Edison Electric Institute (EEI). (November 18, 2022). Clean 
Air Act Section 111 Standards and the Power Sector: Considerations 
and Options for Setting Standards and Providing Compliance 
Flexibility to Units and States. Public comments submitted to the 
EPA's pre-proposal rulemaking, Document ID No. EPA-HQ-OAR-2022-0723-
0024.
    \64\ Energy Strategy Coalition Comments on EPA's proposed New 
Source Performance Standards for Greenhouse Gas Emissions From New, 
Modified, and Reconstructed Fossil Fuel-Fired Electric Generating 
Units; Emission Guidelines for Greenhouse Gas Emissions From 
Existing Fossil Fuel-Fired Electric Generating Units; and Repeal of 
the Affordable Clean Energy Rule, Document ID No. EPA-HQ-OAR-2023-
0072-0672, August 14, 2023.
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B. GHG Emissions From Fossil Fuel-Fired EGUs

    The principal GHGs that accumulate in the Earth's atmosphere above 
pre-industrial levels because of human activity are CO<INF>2</INF>, 
CH<INF>4</INF>, N<INF>2</INF>O, HFCs, PFCs, and SF<INF>6</INF>. Of 
these, CO<INF>2</INF> is the most abundant, accounting for 80 percent 
of all GHGs present in the atmosphere. This abundance of CO<INF>2</INF> 
is largely due to the combustion of fossil fuels by the transportation, 
electricity, and industrial sectors.\65\
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    \65\ U.S. Environmental Protection Agency (EPA). Overview of 
greenhouse gas emissions. July 2021. <a href="https://www.epa.gov/ghgemissions/overview-greenhouse-gases#carbon-dioxide">https://www.epa.gov/ghgemissions/overview-greenhouse-gases#carbon-dioxide</a>.
---------------------------------------------------------------------------

    The amount of CO<INF>2</INF> produced when a fossil fuel is burned 
in an EGU is a function of the carbon content of the fuel relative to 
the size and efficiency of the EGU. Different fuels emit different 
amounts of CO<INF>2</INF> in relation to the energy they produce when 
combusted. The heat content, or the amount of energy produced when a 
fuel is burned, is mainly determined by the carbon and hydrogen content 
of the fuel. For example, in terms of pounds of CO<INF>2</INF> emitted 
per million British thermal units of energy produced when combusted, 
natural gas is the lowest compared to other fossil fuels at 117 lb 
CO<INF>2</INF>/MMBtu.<SUP>66 67</SUP> The average for coal is 216 lb 
CO<INF>2</INF>/MMBtu, but varies between 206 to 229 lb CO<INF>2</INF>/
MMBtu by type (e.g., anthracite, lignite, subbituminous, and 
bituminous).\68\ The value for petroleum products such as diesel fuel 
and heating oil is 161 lb CO<INF>2</INF>/MMBtu.
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    \66\ Natural gas is primarily CH<INF>4</INF>, which has a higher 
hydrogen to carbon atomic ratio, relative to other fuels, and thus, 
produces the least CO<INF>2</INF> per unit of heat released. In 
addition to a lower CO<INF>2</INF> emission rate on a lb/MMBtu 
basis, natural gas is generally converted to electricity more 
efficiently than coal. According to EIA, the 2020 emissions rate for 
coal and natural gas were 2.23 lb CO<INF>2</INF>/kWh and 0.91 lb 
CO<INF>2</INF>/kWh, respectively. <a href="http://www.eia.gov/tools/faqs/faq.php?id=74&t=11">www.eia.gov/tools/faqs/faq.php?id=74&t=11</a>.
    \67\ Values reflect the carbon content on a per unit of energy 
produced on a higher heating value (HHV) combustion basis and are 
not reflective of recovered useful energy from any particular 
technology.
    \68\ Energy Information Administration (EIA). Carbon Dioxide 
Emissions Coefficients. <a href="https://www.eia.gov/environment/emissions/co2_vol_mass.php">https://www.eia.gov/environment/emissions/co2_vol_mass.php</a>.
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    The EPA prepares the official U.S. Inventory of Greenhouse Gas 
Emissions and Sinks \69\ (the U.S. GHG Inventory) to comply with 
commitments under the United Nations Framework Convention on Climate 
Change (UNFCCC). This inventory, which includes recent trends, is 
organized by industrial sectors. It presents total U.S. anthropogenic 
emissions and sinks \70\ of GHGs, including CO<INF>2</INF> emissions 
since 1990. According to the latest inventory of all sectors, in 2021, 
total U.S. GHG emissions were 6,340 million metric tons of 
CO<INF>2</INF> equivalent (MMT CO<INF>2</INF>e).\71\ The transportation 
sector (28.5 percent), which includes approximately 300 million 
vehicles, was the largest contributor to total U.S. GHG emissions with 
1,804 MMT CO<INF>2</INF>e followed by the power sector (25.0 percent) 
with 1,584 MMT CO<INF>2</INF>e. In fact, GHG emissions from the power 
sector were higher than the GHG emissions from all other industrial 
sectors combined (1,487 MMT CO<INF>2</INF>e). Specifically, the power 
sector's emissions were far more than petroleum and natural gas systems 
\72\ at 301 MMT CO<INF>2</INF>e; chemicals (71 MMT CO<INF>2</INF>e); 
minerals (64 MMT CO<INF>2</INF>e); coal mining (53 MMT 
CO<INF>2</INF>e); and metals (48 MMT CO<INF>2</INF>e). The agriculture 
(636 MMT CO<INF>2</INF>e), commercial (439 MMT CO<INF>2</INF>e), and 
residential (366 MMT CO<INF>2</INF>e) sectors combined to emit 1,441 
MMT CO<INF>2</INF>e.
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    \69\ U.S. Environmental Protection Agency (EPA). Inventory of 
U.S. Greenhouse Gas Emissions and Sinks: 1990-2021. <a href="https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks">https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks</a>-1990-2021.
    \70\ Sinks are a physical unit or process that stores GHGs, such 
as forests or underground or deep-sea reservoirs of carbon dioxide.
    \71\ U.S. Environmental Protection Agency (EPA). Inventory of 
U.S. Greenhouse Gas Emissions and Sinks: 1990-2021. <a href="https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks">https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks</a>.
    \72\ Petroleum and natural gas systems include: offshore and 
onshore petroleum and natural gas production; onshore petroleum and 
natural gas gathering and boosting; natural gas processing; natural 
gas transmission/compression; onshore natural gas transmission 
pipelines; natural gas local distribution companies; underground 
natural gas storage; liquified natural gas storage; liquified 
natural gas import/export equipment; and other petroleum and natural 
gas systems.
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    Fossil fuel-fired EGUs are by far the largest stationary source 
emitters of GHGs in the nation. For example, according to the EPA's 
Greenhouse Gas Reporting Program (GHGRP), of the top 100 large 
facilities that reported facility-level GHGs in 2022, 85 were fossil 
fuel-fired power plants while 10 were refineries and/or chemical 
plants, four were metals facilities, and one was a petroleum and 
natural gas systems facility.\73\ Of the 85 fossil fuel-fired power 
plants, 81 were primarily coal-fired, including the top 41 emitters of 
CO<INF>2</INF>. In addition, of the 81 coal-fired plants, 43 have no 
retirement planned prior to 2039. The top 10 of these plants combined 
to emit more than 135 MMT of CO<INF>2</INF>e, with the top emitter 
(James H. Miller power plant in Alabama) reporting approximately 22 MMT 
of CO<INF>2</INF>e with each of its four EGUs emitting between 5 MMT 
and 6 MMT CO<INF>2</INF>e that year. The combined capacity of these 10 
plants is more than 23 gigawatts (GW), and all except for the Monroe 
(Michigan) plant operated at annual capacity factors of 50 percent or 
higher.\74\ For comparison, the largest GHG emitter in the U.S. that is 
not a fossil fuel-fired power plant is the ExxonMobil refinery and 
chemical plant in Baytown, Texas, which reported 12.6 MMT 
CO<INF>2</INF>e (No. 6 overall in the nation) to the GHGRP in 2022. The 
largest metals facility in terms of GHG emissions was the U.S. Steel 
facility in Gary, Indiana, with 10.4 MMT CO<INF>2</INF>e (No. 16 
overall in the nation).
---------------------------------------------------------------------------

    \73\ U.S. Environmental Protection Agency (EPA). Greenhouse Gas 
Reporting Program. Facility Level Information on Greenhouse Gases 
Tool (FLIGHT). <a href="https://ghgdata.epa.gov/ghgp/main.do#">https://ghgdata.epa.gov/ghgp/main.do#</a>.
    \74\ U.S. Energy Information Administration (EIA). Preliminary 
Monthly Electric Generator Inventory, Form EIA-860M, November 2023. 
<a href="https://www.eia.gov/electricity/data/eia860m/">https://www.eia.gov/electricity/data/eia860m/</a>.
---------------------------------------------------------------------------

    Overall, CO<INF>2</INF> emissions from the power sector have 
declined by 36 percent since 2005 (when the power sector reached annual 
emissions of 2,400 MMT CO<INF>2</INF>, its historical peak to 
date).\75\ The reduction in CO<INF>2</INF> emissions can be attributed 
to the power sector's ongoing trend away from carbon-intensive coal-
fired generation and toward more natural gas-fired and renewable 
sources. In 2005, CO<INF>2</INF> emissions from coal-fired EGUs alone 
measured 1,983 MMT.\76\ This total dropped to 1,351 MMT in 2015 and 
reached 974 MMT in 2019, the first time since 1978 that CO<INF>2</INF> 
emissions from coal-fired EGUs were below 1,000 MMT. In 2020, emissions 
of CO<INF>2</INF> from coal-fired EGUs measured 788 MMT as the result 
of pandemic-related closures and reduced utilization before rebounding 
in 2021 to 909 MMT. By contrast, CO<INF>2</INF> emissions from natural 
gas-fired generation have almost doubled since 2005, increasing from 
319 MMT to 613 MMT in 2021, and CO<INF>2</INF> emissions from petroleum 
products (i.e., distillate fuel oil, petroleum coke, and residual fuel 
oil) declined from 98 MMT in 2005 to 18 MMT in 2021.
---------------------------------------------------------------------------

    \75\ U.S. Environmental Protection Agency (EPA). Inventory of 
U.S. Greenhouse Gas Emissions and Sinks: 1990-2020. <a href="https://cfpub.epa.gov/ghgdata/inventoryexplorer/#electricitygeneration/entiresector/allgas/category/all">https://cfpub.epa.gov/ghgdata/inventoryexplorer/#electricitygeneration/entiresector/allgas/category/all</a>.
    \76\ U.S. Energy Information Administration (EIA). Monthly 
Energy Review, table 11.6. September 2022. <a href="https://www.eia.gov/totalenergy/data/monthly/pdf/sec11.pdf">https://www.eia.gov/totalenergy/data/monthly/pdf/sec11.pdf</a>.

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[[Page 39813]]

    When the EPA finalized the Clean Power Plan (CPP) in October 2015, 
the Agency projected that, as a result of the CPP, the power sector 
would reduce its annual CO<INF>2</INF> emissions to 1,632 MMT by 2030, 
or 32 percent below 2005 levels (2,400 MMT).\77\ Instead, even in the 
absence of Federal regulations for existing EGUs, annual CO<INF>2</INF> 
emissions from sources covered by the CPP had fallen to 1,540 MMT by 
the end of 2021, a nearly 36 percent reduction below 2005 levels. The 
power sector achieved a deeper level of reductions than forecast under 
the CPP and approximately a decade ahead of time. By the end of 2015, 
several months after the CPP was finalized, those sources already had 
achieved CO<INF>2</INF> emission levels of 1,900 MMT, or approximately 
21 percent below 2005 levels. However, progress in emission reductions 
is not uniform across all states and is not guaranteed to continue, 
therefore Federal policies play an essential role. As discussed earlier 
in this section, the power sector remains a leading emitter of 
CO<INF>2</INF> in the U.S., and, despite the emission reductions since 
2005, current CO<INF>2</INF> levels continue to endanger human health 
and welfare. Further, as sources in other sectors of the economy turn 
to electrification to decarbonize, future CO<INF>2</INF> reductions 
from fossil fuel-fired EGUs have the potential to take on added 
significance and increased benefits.
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    \77\ 80 FR 63662 (October 23, 2015).
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C. Recent Developments in Emissions Control

    This section of the preamble describes recent developments in GHG 
emissions control in general. Details of those controls in the context 
of BSER determination are provided in section VII.C.1.a for CCS on 
coal-fired steam generating units, section VII.C.2.a for natural gas 
co-firing on coal-fired steam generating units, section VIII.F.2.b for 
efficient generation on natural gas-fired combustion turbines, and 
section VIII.F.4.c.iv for CCS on natural gas-fired combustion turbines. 
Further details of the control technologies are available in the final 
TSDs, GHG Mitigation Measures for Steam Generating Units and GHG 
Mitigation Measures--CCS for Combustion Turbines, available in the 
docket for these actions.
1. CCS
    One of the key GHG reduction technologies upon which the BSER 
determinations are founded in these final rules is CCS--a technology 
that can capture and permanently store CO<INF>2</INF> from fossil fuel-
fired EGUs. CCS has three major components: CO<INF>2</INF> capture, 
transportation, and sequestration/storage. Solvent-based CO<INF>2</INF> 
capture was patented nearly 100 years ago in the 1930s \78\ and has 
been used in a variety of industrial applications for decades. 
Thousands of miles of CO<INF>2</INF> pipelines have been constructed 
and securely operated in the U.S. for decades.\79\ And tens of millions 
of tons of CO<INF>2</INF> have been permanently stored deep underground 
either for geologic sequestration or in association with enhanced oil 
recovery (EOR).\80\ The American Petroleum Institute (API) explains 
that ``CCS is a proven technology'' and that ``[t]he methods that apply 
to [the] carbon sequestration process are not novel. The U.S. has more 
than 40 years of CO<INF>2</INF> gas injection and storage experience. 
During the last 40 years the U.S. gas and oil industry's (EOR) enhanced 
oil recovery operations) have injected more than 1 billion tonnes of 
CO<INF>2</INF>.'' <SUP>81 82</SUP>
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    \78\ Bottoms, R.R. Process for Separating Acidic Gases (1930) 
United States patent application. United States Patent US1783901A; 
Allen, A.S. and Arthur, M. Method of Separating Carbon Dioxide from 
a Gas Mixture (1933) United States Patent Application. United States 
Patent US1934472A.
    \79\ U.S. Department of Transportation, Pipeline and Hazardous 
Material Safety Administration, ``Hazardous Annual Liquid Data.'' 
2022. <a href="https://www.phmsa.dot.gov/data-and-statistics/pipeline/gas-distribution-gas-gathering-gas-transmission-hazardous-liquids">https://www.phmsa.dot.gov/data-and-statistics/pipeline/gas-distribution-gas-gathering-gas-transmission-hazardous-liquids</a>.
    \80\ GHGRP US EPA. <a href="https://www.epa.gov/ghgreporting/supply-underground-injection-and-geologic-sequestration-carbon-dioxide">https://www.epa.gov/ghgreporting/supply-underground-injection-and-geologic-sequestration-carbon-dioxide</a>.
    \81\ American Petroleum Institute (API). (2024). Carbon Capture 
and Storage: A Low-Carbon Solution to Economy-Wide Greenhouse Gas 
Emissions Reductions. <a href="https://www.api.org/news-policy-and-issues/carbon-capture-storage">https://www.api.org/news-policy-and-issues/carbon-capture-storage</a>.
    \82\ Major energy company presidents have made similar 
statements. For example, in 2021, Shell Oil Company president 
Gretchen H. Watkins testified to Congress that ``Carbon capture and 
storage is a proven technology,'' and in 2022, Joe Blommaert, the 
president of ExxonMobil Low Carbon Solutions, stated that ``Carbon 
capture and storage is a readily available technology that can play 
a critical role in helping society reduce greenhouse gas 
emissions.'' See <a href="https://www.congress.gov/117/meeting/house/114185/witnesses/HHRG-117-GO00-Wstate-WatkinsG-20211028.pdf">https://www.congress.gov/117/meeting/house/114185/witnesses/HHRG-117-GO00-Wstate-WatkinsG-20211028.pdf</a> and <a href="https://corporate.exxonmobil.com/news/news-releases/2022/0225_exxonmobil-to-expand-carbon-capture-and-storage-at-labarge-wyoming-facility">https://corporate.exxonmobil.com/news/news-releases/2022/0225_exxonmobil-to-expand-carbon-capture-and-storage-at-labarge-wyoming-facility</a>.
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    In 2009, Mike Morris, then-CEO of American Electric Power (AEP), 
was interviewed by Reuters and the article noted that Morris's 
``companies' work in West Virginia on [CCS] gave [Morris] more insight 
than skeptics who doubt the technology.'' In that interview, Morris 
explained, ``I'm convinced it will be primetime ready by 2015 and 
deployable.'' \83\ In 2011, Alstom Power, the company that developed 
the 30 MW pilot project upon which Morris had based his conclusions, 
reiterated the claim that CCS would be commercially available in 2015. 
A press release from Alstom Power stated that, based on the results of 
Alstom's ``13 pilot and demonstration projects and validated by 
independent experts . . . we can now be confident that CCS works and is 
cost effective . . . and will be available at a commercial scale in 
2015 and will allow [plants] to capture 90% of the emitted 
CO<INF>2</INF>.'' The press release went on to note that ``the same 
conclusion applies for a gas plant using CCS.'' \84\
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    \83\ Woodall, B. (June 25, 2009). AEP sees carbon capture from 
coal ready by 2015. Reuters. <a href="https://www.reuters.com/article/idUSTRE55O6TS/">https://www.reuters.com/article/idUSTRE55O6TS/</a>.
    \84\ Alstom Power. (June 14, 2011). Alstom Power study 
demonstrates carbon capture and storage (CCS) is efficient and cost 
competitive. <a href="https://www.alstom.com/press-releases-news/2011/6/press-releases-3-26">https://www.alstom.com/press-releases-news/2011/6/press-releases-3-26</a>.
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    In 2011, however, AEP determined that the economic and regulatory 
environment at the time did not support further development of the 
technology. After canceling a large-scale commercial project, Morris 
explained, ``as a regulated utility, it is impossible to gain 
regulatory approval to cover our share of the costs for validating and 
deploying the technology without federal requirements to reduce 
greenhouse gas emissions already in place.'' \85\
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    \85\ Indiana Michigan Power. (July 14, 2011). AEP Places Carbon 
Capture Commercialization on Hold, Citing Uncertain Status of 
Climate Policy, Weak Economy. Press release. <a href="https://www.indianamichiganpower.com/company/news/view?releaseID=1206">https://www.indianamichiganpower.com/company/news/view?releaseID=1206</a>.
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    Thirteen years later, the situation is fundamentally different. 
Since 2011, the technological advances from full-scale deployments 
(e.g., the Petra Nova and Boundary Dam projects discussed later in this 
preamble) combined with supportive policies in multiple states and the 
financial incentives included in the IRA, mean that CCS can be deployed 
at scale today. In addition to applications at fossil fuel-fired EGUs, 
installation of CCS is poised to dramatically increase across a range 
of industries in the coming years, including ethanol production, 
natural gas processing, and steam methane reformers.\86\ Many of the 
CCS projects across these industries, including capture systems, 
pipelines, and sequestration, are already in operation or are in 
advanced stages of deployment. There are currently at least 15 
operating CCS projects in the U.S., and another 121 that are under

[[Page 39814]]

construction or in advanced stages of development.\87\
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    \86\ U.S. Department of Energy (DOE). (2023). Pathways to 
Commercial Liftoff: Carbon Management. <a href="https://liftoff.energy.gov/wp-content/uploads/2024/02/20230424-Liftoff-Carbon-Management-vPUB_update4.pdf">https://liftoff.energy.gov/wp-content/uploads/2024/02/20230424-Liftoff-Carbon-Management-vPUB_update4.pdf</a>.
    \87\ Congressional Budget Office (CBO). (December 13, 2023). 
Carbon Capture and Storage in the United States. <a href="https://www.cbo.gov/publication/59345">https://www.cbo.gov/publication/59345</a>.
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    Process improvements learned from earlier deployments of CCS, the 
availability of better solvents, and other advances have decreased the 
costs of CCS in recent years. As a result, the cost of CO<INF>2</INF> 
capture, excluding any tax credits, from coal-fired power generation is 
projected to fall by 50 percent by 2025 compared to 2010.\88\ The IRA 
makes additional and significant reductions in the cost of implementing 
CCS by extending and increasing the tax credit for CO<INF>2</INF> 
sequestration under IRC section 45Q.
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    \88\ Global CCS Institute. (March 2021). Technology Readiness 
and Costs of CCS. <a href="https://www.globalccsinstitute.com/wp-content/uploads/2021/03/Technology-Readiness-and-Costs-for-CCS-2021-1.pdf">https://www.globalccsinstitute.com/wp-content/uploads/2021/03/Technology-Readiness-and-Costs-for-CCS-2021-1.pdf</a>.
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    With this combination of polices, and the advances related to 
CO<INF>2</INF> capture, multiple projects consistent with the emission 
reduction requirements of a 90 percent capture amine based BSER are in 
advanced stages of development. These projects use a wider range of 
technologies, and some of them are being developed as first-of-a-kind 
projects and offer significant advantages over the amine-based CCS 
technology that the EPA is finalizing as BSER.
    For instance, in North Dakota, Governor Doug Burgum announced a 
goal of becoming carbon neutral by 2030 while retaining the core 
position of its fossil fuel industries, and to do so by significant CCS 
implementation. Gov. Burgum explained, ``This may seem like a moonshot 
goal, but it's actually not. It's actually completely doable, even with 
the technologies that we have today.'' \89\ Companies in the state are 
backing up this claim with projects in multiple industries in various 
stages of operation and development. In the power sector, two of the 
biggest projects under development are Project Tundra and Coal Creek. 
Project Tundra is a carbon capture project on Minnkota Power's 705 MW 
Milton R Young Power Plant in Oliver County, North Dakota. Mitsubishi 
Heavy Industries will be providing an advanced version of its carbon 
capture equipment that builds upon the lessons learned from the Petra 
Nova project.\90\ Rainbow Energy is developing the project at the Coal 
Creek Station, located in McLean, North Dakota. Notably, Rainbow Energy 
purchased the 1,150 MW Coal Creek Station with a business model of 
installing CCS based on the IRC section 45Q tax credit of $50/ton that 
existed at the time (the IRA has since increased the amount to $85/
ton).\91\ Rainbow Energy explains, ``CCUS technology has been proven 
and is an economical option for a facility like Coal Creek Station. We 
see CCUS as the best way to manage emissions at our facility.'' \92\
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    \89\ Willis, A. (May 12, 2021). Gov. Doug Burgum calls for North 
Dakota to be carbon neutral by 2030. The Dickinson Press. <a href="https://www.thedickinsonpress.com/business/gov-doug-burgum-calls-for-north-dakota-to-be-carbon-neutral-by-2030">https://www.thedickinsonpress.com/business/gov-doug-burgum-calls-for-north-dakota-to-be-carbon-neutral-by-2030</a>.
    \90\ Tanaka, H. et al. Advanced KM CDR Process using New 
Solvent. 14th International Conference on Greenhouse Gas Control 
Technologies, GHGT-14. <a href="https://www.cfaenm.org/wp-content/uploads/2019/03/GHGT14_manuscript_20180913Clean-version.pdf">https://www.cfaenm.org/wp-content/uploads/2019/03/GHGT14_manuscript_20180913Clean-version.pdf</a>.
    \91\ Minot Daily News. (April 8, 2024). Hoeven: ND to lead 
country with carbon capture project at Coal Creek Station. <a href="https://minotdailynews.com/news/local-news/2021/07/hoeven-nd-to-lead-country-with-carbon-capture-project-at-coal-creek-station/">https://minotdailynews.com/news/local-news/2021/07/hoeven-nd-to-lead-country-with-carbon-capture-project-at-coal-creek-station/</a>.
    \92\ Rainbow Energy Center. (ND). Carbon Capture. <a href="https://rainbowenergycenter.com/what-we-do/carbon-capture/">https://rainbowenergycenter.com/what-we-do/carbon-capture/</a>.
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    While North Dakota has encouraged CCS on coal-fired power plants 
without specific mandates, Wyoming is taking a different approach. 
Senate Bill 42, enacted in 2024, requires utilities to generate a 
specified percentage of their electricity using coal-fired power plants 
with CCS. SB 42 updates HB 200, enacted in 2020, which required the CCS 
to be installed by 2030, which SB 42 extends to 2033. To comply with 
those requirements, PacificCorp has stated in its 2023 IRP that it 
intends to install CCS on two coal-fired units by 2028.\93\ Rocky 
Mountain Power has also announced that it will explore a new carbon 
capture technology at either its David Johnston plant or its Wyodak 
plant.\94\ Another CCS project is also under development at the Dry 
Fork Power Plant in Wyoming. Currently, a pilot project that will 
capture 150 tons of CO<INF>2</INF> per day is under construction and is 
scheduled to be completed in late 2024. Work has also begun on a full-
scale front end engineering design (FEED) study.
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    \93\ PacifiCorp. (April 1, 2024). 2023 Integrated Resource Plan 
Update. <a href="https://www.pacificorp.com/content/dam/pcorp/documents/en/pacificorp/energy/integrated-resource-plan/2023_IRP_Update.pdf">https://www.pacificorp.com/content/dam/pcorp/documents/en/pacificorp/energy/integrated-resource-plan/2023_IRP_Update.pdf</a>.
    \94\ Rocky Mountain Power. (April 1, 2024). Rocky Mountain Power 
and 8 Rivers to collaborate on proposed Wyoming carbon capture 
project. Press release. <a href="https://www.rockymountainpower.net/about/newsroom/news-releases/rmp-proposed-wyoming-carbon-capture-project.html">https://www.rockymountainpower.net/about/newsroom/news-releases/rmp-proposed-wyoming-carbon-capture-project.html</a>.
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    Like North Dakota, West Virginia does not have a carbon capture 
mandate, but there are several carbon capture projects under 
development in the state. One is a new, 2,000 MW natural gas combined 
cycle plant being developed by Competitive Power Ventures that will 
capture 90-95 percent of the CO<INF>2</INF> using GE turbine and carbon 
capture technology.\95\ A second is an Omnis Fuel Technologies project 
to convert the coal-fired Pleasants Power Station to run on 
hydrogen.\96\ Omnis intends to use a pyrolysis-based process to convert 
coal into hydrogen and graphite. Because the graphite is a usable, 
solid form of carbon, no CO<INF>2</INF> sequestration will be required. 
Therefore, unlike more traditional amine-based approaches, instead of 
the captured CO<INF>2</INF> being a cost, the graphite product will 
provide a revenue stream.\97\ Omnis states that the Pleasants Power 
Project broke ground in August 2023 and will be online by 2025.
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    \95\ Competitive Power Ventures (CPV). Shay Clean Energy Center. 
<a href="https://www.cpv.com/our-projects/cpv-shay-energy-center/">https://www.cpv.com/our-projects/cpv-shay-energy-center/</a>.
    \96\ The Associated Press (AP). (August 30, 2023). New owner 
restarts West Virginia coal-fired power plant and intends to convert 
it to hydrogen use. <a href="https://apnews.com/article/west-virginia-power-plant-coal-hydrogen-7b46798c8e3b093a8591f25f66340e8f">https://apnews.com/article/west-virginia-power-plant-coal-hydrogen-7b46798c8e3b093a8591f25f66340e8f</a>.
    \97\ <a href="http://omnigenglobal.com">omnigenglobal.com</a>.
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    It should be noted that Wyoming, West Virginia, and North Dakota 
represented the first-, second-, and seventh-largest coal producers, 
respectively, in the U.S. in 2022.\98\
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    \98\ U.S. Energy Information Administration (EIA). (October 
2023). Annual Coal Report 2022. <a href="https://www.eia.gov/coal/annual/pdf/acr.pdf">https://www.eia.gov/coal/annual/pdf/acr.pdf</a>.
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    In addition to the coal-based CCS projects mentioned above, 
multiple other projects are in advanced stages of development and/or 
have completed FEED studies. For instance, Linde/BASF is installing a 
10 MW pilot project on the Dallman Power Plant in Illinois. Based on 
results from small scale pilot studies, techno economic analysis 
indicates that the Linde/BASF process can provide a significant 
reduction in capital costs compared to the NETL base case for a 
supercritical pulverized coal plant with carbon capture.'' \99\ 
Multiple other FEED studies are either completed or under development, 
putting those projects on a path to being able to be built and to 
commence operation well before January 1, 2032.
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    \99\ National Energy Technology Laboratory (NETL). Large Pilot 
Carbon Capture Project Supported by NETL Breaks Ground in Illinois. 
<a href="https://netl.doe.gov/node/12284">https://netl.doe.gov/node/12284</a>.
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    In addition to the Competitive Power Partners project, there are 
multiple post-combustion CCS retrofit projects in various stages of 
development. In particular, NET Power is in advanced stages of 
development on a 300 MW project in west Texas using the Allam-Fetvedt 
cycle, which is being designed to achieve greater than 97 percent 
CO<INF>2</INF> capture. In addition to working on this first project, 
NET Power has indicated that it has an additional project under 
development and is working with

[[Page 39815]]

suppliers to support additional future projects.\100\
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    \100\ Net Power. (March 11, 2024). Q4 2023 Business Update and 
Results. <a href="https://d1io3yog0oux5.cloudfront.net/_cde4aad258e20f5aec49abd8654499f8/netpower/db/3583/33195/pdf/Q4_2023+Earnings+Presentation_3.11.24.pdf">https://d1io3yog0oux5.cloudfront.net/_cde4aad258e20f5aec49abd8654499f8/netpower/db/3583/33195/pdf/Q4_2023+Earnings+Presentation_3.11.24.pdf</a>.
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    In developing these final rules, the EPA reviewed the current state 
and cost of CCS technology for use with both steam generating units and 
stationary combustion turbines. This review is reflected in the 
respective BSER discussions later in this preamble and is further 
detailed in the accompanying RIA and final TSDs, GHG Mitigation 
Measures for Steam Generating Units and GHG Mitigation Measures--Carbon 
Capture and Storage for Combustion Turbines. These documents are 
included in the rulemaking docket.
2. Natural Gas Co-Firing
    For a coal-fired steam generating unit, the substitution of natural 
gas for some of the coal so that the unit fires a combination of coal 
and natural gas is known as ``natural gas co-firing.'' Existing coal-
fired steam generating units can be modified to co-fire natural gas in 
any desired proportion with coal. Generally, the modification of 
existing boilers to enable or increase natural gas firing involves the 
installation of new gas burners and related boiler modifications and 
may involve the construction of a natural gas supply pipeline if one 
does not already exist. In recent years, the cost of natural gas co-
firing has declined because the expected difference between coal and 
gas prices has decreased and analysis supports lower capital costs for 
modifying existing boilers to co-fire with natural gas, as discussed in 
section VII.C.2.a of this preamble.
    It is common practice for steam generating units to have the 
capability to burn multiple fuels onsite, and of the 565 coal-fired 
steam generating units operating at the end of 2021, 249 of them 
reported use of natural gas as a primary fuel or for startup.\101\ 
Based on hourly reported CO<INF>2</INF> emission rates from the start 
of 2015 through the end of 2020, 29 coal-fired steam generating units 
co-fired with natural gas at rates at or above 60 percent of capacity 
on an hourly basis.\102\ The capability of those units on an hourly 
basis is indicative of the extent of boiler burner modifications and 
sizing and capacity of natural gas pipelines to those units, and it 
implies that those units are technically capable of co-firing at least 
60 percent natural gas on a heat input basis on average over the course 
of an extended period (e.g., a year). Additionally, many coal-fired 
steam generating EGUs have also opted to switch entirely to providing 
generation from the firing of natural gas. Since 2011, more than 80 
coal-fired utility boilers have been converted to natural gas-fired 
utility boilers.\103\
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    \101\ U.S. Energy Information Administration (EIA). Form 923. 
<a href="https://www.eia.gov/electricity/data/eia923/">https://www.eia.gov/electricity/data/eia923/</a>.
    \102\ U.S. Environmental Protection Agency (EPA). ``Power Sector 
Emissions Data.'' Washington, DC: Office of Atmospheric Protection, 
Clean Air Markets Division. <a href="https://campd.epa.gov">https://campd.epa.gov</a>.
    \103\ U.S. Energy Information Administration (EIA). (5 August 
2020). Today in Energy. More than 100 coal-fired plants have been 
replaced or converted to natural gas since 2011. <a href="https://www.eia.gov/todayinenergy/detail.php?id=44636">https://www.eia.gov/todayinenergy/detail.php?id=44636</a>.
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    In developing these final actions, the EPA reviewed in detail the 
current state of natural gas co-firing technology and costs. This 
review is reflected in the BSER discussions later in this preamble and 
is further detailed in the accompanying RIA and final TSD, GHG 
Mitigation Measures for Steam Generating Units. Both documents are 
included in the rulemaking docket.
3. Efficient Generation
    Highly efficient generation is the BSER technology upon which the 
first phase standards of performance are based for certain new and 
reconstructed stationary combustion turbine EGUs. This technology is 
available for both simple cycle and combined cycle combustion turbines 
and has been demonstrated--along with best operating and maintenance 
practices--to reduce emissions. Generally, as the thermal efficiency of 
a combustion turbine increases, less fuel is burned per gross MWh of 
electricity produced and there is a corresponding decrease in 
CO<INF>2</INF> and other air emissions.
    For simple cycle turbines, manufacturers continue to improve the 
efficiency by increasing firing temperature, increasing pressure 
ratios, using intercooling on the air compressor, and adopting other 
measures. Best operating practices for simple cycle turbines include 
proper maintenance of the combustion turbine flow path components and 
the use of inlet air cooling to reduce efficiency losses during periods 
of high ambient temperatures. For combined cycle turbines, a highly 
efficient combustion turbine engine is matched with a high-efficiency 
HRSG. High efficiency also includes, but is not limited to, the use of 
the most efficient steam turbine and minimizing energy losses using 
insulation and blowdown heat recovery. Best operating and maintenance 
practices include, but are not limited to, minimizing steam leaks, 
minimizing air infiltration, and cleaning and maintaining heat transfer 
surfaces.
    As discussed in section VIII.F.2.b of this preamble, efficient 
generation technologies have been in use at facilities in the power 
sector for decades and the levels of efficiency that the EPA is 
finalizing in this rule have been achieved by many recently constructed 
turbines. The efficiency improvements are incremental in nature and do 
not change how the combustion turbine is operated or maintained and 
present little incremental capital or compliance costs compared to 
other types of technologies that may be considered for new and 
reconstructed sources. In addition, more efficient designs have lower 
fuel costs, which offset at least a portion of the increase in capital 
costs. For additional discussion of this BSER technology, see the final 
TSD, Efficient Generation in Combustion Turbines in the docket for this 
rulemaking.
    Efficiency improvements are also available for fossil fuel-fired 
steam generating units, and as discussed further in section VII.D.4.a, 
the more efficiently an EGU operates the less fuel it consumes, thereby 
emitting lower amounts of CO<INF>2</INF> and other air pollutants per 
MWh generated. Efficiency improvements for steam generating EGUs 
include a variety of technology upgrades and operating practices that 
may achieve CO<INF>2</INF> emission rate reductions of 0.1 to 5 percent 
for individual EGUs. These reductions are small relative to the 
reductions that are achievable from natural gas co-firing and from CCS. 
Also, as efficiency increases, some facilities could increase their 
utilization and therefore increase their CO<INF>2</INF> emissions (as 
well as emissions of other air pollutants). This phenomenon is known as 
the ``rebound effect.'' Because of this potential for perverse GHG 
emission outcomes resulting from deployment of efficiency measures at 
certain steam generating units, coupled with the relatively minor 
overall GHG emission reductions that would be expected, the EPA is not 
finalizing efficiency improvements as the BSER for any subcategory of 
existing coal-fired steam generating units. Specific details of 
efficiency measures are described in the final TSD, GHG Mitigation 
Measures for Steam Generating Units, and an updated 2023 Sargent and 
Lundy HRI report (Heat Rate Improvement Method Costs and Limitations 
Memo), available in the docket.

[[Page 39816]]

D. The Electric Power Sector: Trends and Current Structure

1. Overview
    The electric power sector is experiencing a prolonged period of 
transition and structural change. Since the generation of electricity 
from coal-fired power plants peaked nearly two decades ago, the power 
sector has changed at a rapid pace. Today, natural gas-fired power 
plants provide the largest share of net generation, coal-fired power 
plants provide a significantly smaller share than in the recent past, 
renewable energy provides a steadily increasing share, and as new 
technologies enter the marketplace, power producers continue to replace 
aging assets--especially coal-fired power plants--with more efficient 
and lower-cost alternatives.
    These developments have significant implications for the types of 
controls that the EPA determined to qualify as the BSER for different 
types of fossil fuel-fired EGUs. For example, power plant owners and 
operators retired an average annual coal-fired EGU capacity of 10 GW 
from 2015 to 2023, and coal-fired EGUs comprised 58 percent of all 
retired capacity in 2023.\104\ While use of CCS promises significant 
emissions reduction from fossil fuel-fired sources, it requires 
substantial up-front capital expenditure. Therefore, it is not a 
feasible or cost-reasonable emission reduction technology for units 
that intend to cease operation before they would be able to amortize 
its costs. Industry stakeholders requested that the EPA structure these 
rules to avoid imposing costly control obligations on coal-fired power 
plants that have announced plans to voluntarily cease operations, and 
the EPA has determined the BSER in accordance with its understanding of 
which coal-fired units will be able to feasibly and cost-effectively 
deploy the BSER technologies. In addition, the EPA recognizes that 
utilities and power plant operators are building new natural gas-fired 
combustion turbines with plans to operate them at varying levels of 
utilization, in coordination with other existing and expected new 
energy sources. These patterns of operation are important for the type 
of controls that the EPA is finalizing as the BSER for these turbines.
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    \104\ U.S. Energy Information Administration (EIA). (7 February 
2023). Today in Energy. Coal and natural gas plants will account for 
98 percent of U.S. capacity retirements in 2023. <a href="https://www.eia.gov/todayinenergy/detail.php?id=55439">https://www.eia.gov/todayinenergy/detail.php?id=55439</a>.
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2. Broad Trends Within the Power Sector
    For more than a decade, the power sector has been experiencing 
substantial transition and structural change, both in terms of the mix 
of generating capacity and in the share of electricity generation 
supplied by different types of EGUs. These changes are the result of 
multiple factors, including normal replacements of older EGUs; 
technological improvements in electricity generation from both existing 
and new EGUs; changes in the prices and availability of different 
fuels; state and Federal policy; the preferences and purchasing 
behaviors of end-use electricity consumers; and substantial growth in 
electricity generation from renewable sources.
    One of the most important developments of this transition has been 
the evolving economics of the power sector. Specifically, as discussed 
in section IV.D.3.b of this preamble and in the final TSD, Power Sector 
Trends, the existing fleet of coal-fired EGUs continues to age and 
become more costly to maintain and operate. At the same time, natural 
gas prices have held relatively low due to increased supply, and 
renewable costs have fallen rapidly with technological improvement and 
growing scale. Natural gas surpassed coal in monthly net electricity 
generation for the first time in April 2015, and since that time 
natural gas has maintained its position as the primary fuel for base 
load electricity generation, for peaking applications, and for 
balancing renewable generation.\105\ In 2023, generation from natural 
gas was more than 2.5 times as much as generation from coal.\106\ 
Additionally, there has been increased generation from investments in 
zero- and low-GHG emission energy technologies spurred by technological 
advancements, declining costs, state and Federal policies, and most 
recently, the IIJA and the IRA. For example, the IIJA provides 
investments and other policies to help commercialize, demonstrate, and 
deploy technologies such as small modular nuclear reactors, long-
duration energy storage, regional clean hydrogen hubs, CCS and 
associated infrastructure, advanced geothermal systems, and advanced 
distributed energy resources (DER) as well as more traditional wind, 
solar, and battery energy storage resources. The IRA provides numerous 
tax and other incentives to directly spur deployment of clean energy 
technologies. Particularly relevant to these final actions, the 
incentives in the IRA,<SUP>107 108</SUP> which are discussed in detail 
later in this section of the preamble, support the expansion of 
technologies, such as CCS, that reduce GHG emissions from fossil-fired 
EGUs.
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    \105\ U.S. Energy Information Administration (EIA). Monthly 
Energy Review and Short-Term Energy Outlook, March 2016. <a href="https://www.eia.gov/todayinenergy/detail.php?id=25392">https://www.eia.gov/todayinenergy/detail.php?id=25392</a>.
    \106\ U.S. Energy Information Administration (EIA). Electric 
Power Monthly, March 2024. <a href="https://www.eia.gov/electricity/monthly/current_month/march2024.pdf">https://www.eia.gov/electricity/monthly/current_month/march2024.pdf</a>.
    \107\ U.S. Department of Energy (DOE). August 2022. The 
Inflation Reduction Act Drives Significant Emissions Reductions and 
Positions America to Reach Our Climate Goals. <a href="https://www.energy.gov/sites/default/files/2022-08/8.18%20InflationReductionAct_Factsheet_Final.pdf">https://www.energy.gov/sites/default/files/2022-08/8.18%20InflationReductionAct_Factsheet_Final.pdf</a>.
    \108\ U.S. Department of Energy (DOE). August 2023. Investing in 
American Energy. Significant Impacts of the Inflation Reduction Act 
and Bipartisan Infrastructure Law on the U.S. Energy Economy and 
Emissions Reductions. <a href="https://www.energy.gov/sites/default/files/2023-08/DOE%20OP%20Economy%20Wide%20Report_0.pdf">https://www.energy.gov/sites/default/files/2023-08/DOE%20OP%20Economy%20Wide%20Report_0.pdf</a>.
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    The ongoing transition of the power sector is illustrated by a 
comparison of data between 2007 and 2022. In 2007, the year of peak 
coal generation, approximately 72 percent of the electricity provided 
to the U.S. grid was produced through the combustion of fossil fuels, 
primarily coal and natural gas, with coal accounting for the largest 
single share. By 2022, fossil fuel net generation was approximately 60 
percent, less than the share in 2007 despite electricity demand 
remaining relatively flat over this same period. Moreover, the share of 
generation supplied by coal-fired EGUs fell from 49 percent in 2007 to 
19 percent in 2022 while the share supplied by natural gas-fired EGUs 
rose from 22 to 39 percent during the same period. In absolute terms, 
coal-fired generation declined by 59 percent while natural gas-fired 
generation increased by 88 percent. This reflects both the increase in 
natural gas capacity as well as an increase in the utilization of new 
and existing natural gas-fired EGUs. The combination of wind and solar 
generation also grew from 1 percent of the electric power sector mix in 
2007 to 15 percent in 2022.\109\
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    \109\ U.S. Energy Information Administration (EIA). Annual 
Energy Review, table 8.2b Electricity net generation: electric power 
sector. <a href="https://www.eia.gov/totalenergy/data/annual/">https://www.eia.gov/totalenergy/data/annual/</a>.
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    Additional analysis of the utility power sector, including 
projections of future power sector behavior and the impacts of these 
final rules, is discussed in more detail in section XII of this 
preamble, in the accompanying RIA, and in the final TSD, Power Sector 
Trends. The latter two documents are available in the rulemaking 
docket. Consistent with analyses done by other energy modelers, the 
information

[[Page 39817]]

provided in the RIA and TSD demonstrates that the sector trend of 
moving away from coal-fired generation is likely to continue, the share 
from natural gas-fired generation is projected to decline eventually, 
and the share of generation from non-emitting technologies is likely to 
continue increasing. For instance, according to the Energy Information 
Administration (EIA), the net change in solar capacity has been larger 
than the net change in capacity for any other source of electricity for 
every year since 2020. In 2024, EIA projects that the actual increase 
in generation from solar will exceed every other source of generating 
capacity. This is in part because of the large amounts of new solar 
coming online in 2024 but is also due to the large amount of energy 
storage coming online, which will help reduce renewable 
curtailments.\110\ EIA also projects that in 2024, the U.S. will see 
its largest year for installation of both solar and battery storage. 
Specifically, EIA projects that 36.4 GW of solar will be added, nearly 
doubling last year's record of 18.4 GW. Similarly, EIA projects 14.3 GW 
of new energy storage. This would more than double last year's record 
installation of 6.4 GW and nearly double the existing total capacity of 
15.5 GW. This compares to only 2.5 GW of new natural gas turbine 
capacity.\111\ The only year since 2013 when renewable generation did 
not make up the majority of new generation capacity in the U.S. was 
2018.\112\
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    \110\ U.S. Energy Information Administration (EIA). Short Term 
Energy Outlook, December 2023.
    \111\ U.S. Energy Information Administration (EIA). (February 
15, 2024). Today in Energy. Solar and Battery Storage to make up 81% 
of new U.S. Electric-generating capacity in 2024. <a href="https://www.eia.gov/todayinenergy/detail.php?id=61424">https://www.eia.gov/todayinenergy/detail.php?id=61424</a>.
    \112\ U.S. Energy Information Administration (EIA). Today in 
Energy. Natural gas and renewables make up most of 2018 electric 
capacity additions. <a href="https://www.eia.gov/todayinenergy/detail.php?id=36092">https://www.eia.gov/todayinenergy/detail.php?id=36092</a>.
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3. Coal-Fired Generation: Historical Trends and Current Structure
a. Historical Trends in Coal-Fired Generation
    Coal-fired steam generating units have historically been the 
nation's foremost source of electricity, but coal-fired generation has 
declined steadily since its peak approximately 20 years ago.\113\ 
Construction of new coal-fired steam generating units was at its 
highest between 1967 and 1986, with approximately 188 GW (or 9.4 GW per 
year) of capacity added to the grid during that 20-year period.\114\ 
The peak annual capacity addition was 14 GW, which was added in 1980. 
These coal-fired steam generating units operated as base load units for 
decades. However, beginning in 2005, the U.S. power sector--and 
especially the coal-fired fleet--began experiencing a period of 
transition that continues today. Many of the older coal-fired steam 
generating units built in the 1960s, 1970s, and 1980s have retired or 
have experienced significant reductions in net generation due to cost 
pressures and other factors. Some of these coal-fired steam generating 
units repowered with combustion turbines and natural gas.\115\ With no 
new coal-fired steam generating units larger than 25 MW commencing 
construction in the past decade--and with the EPA unaware of any plans 
being approved to construct a new coal-fired EGU--much of the fleet 
that remains is aging, expensive to operate and maintain, and 
increasingly uncompetitive relative to other sources of generation in 
many parts of the country.
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    \113\ U.S. Energy Information Administration (EIA). Today in 
Energy. Natural gas expected to surpass coal in mix of fuel used for 
U.S. power generation in 2016. March 2016. <a href="https://www.eia.gov/todayinenergy/detail.php?id=25392">https://www.eia.gov/todayinenergy/detail.php?id=25392</a>.
    \114\ U.S. Energy Information Administration (EIA). Electric 
Generators Inventory, Form EIA-860M, Inventory of Operating 
Generators and Inventory of Retired Generators, March 2022. <a href="https://www.eia.gov/electricity/data/eia860m/">https://www.eia.gov/electricity/data/eia860m/</a>.
    \115\ U.S. Energy Information Administration (EIA). Today in 
Energy. More than 100 coal-fired plants have been replaced or 
converted to natural gas since 2011. August 2020. <a href="https://www.eia.gov/todayinenergy/detail.php?id=44636">https://www.eia.gov/todayinenergy/detail.php?id=44636</a>.
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    Since 2007, the power sector's total installed net summer capacity 
\116\ has increased by 167 GW (17 percent) while coal-fired steam 
generating unit capacity has declined by 123 GW.\117\ This reduction in 
coal-fired steam generating unit capacity was offset by a net increase 
in total installed wind capacity of 125 GW, net natural gas capacity of 
110 GW, and a net increase in utility-scale solar capacity of 71 GW 
during the same period. Additionally, significant amounts (40 GW) of 
DER solar were also added. At least half of these changes were in the 
most recent 7 years of this period. From 2015 to 2022, coal capacity 
was reduced by 90 GW and this reduction in capacity was offset by a net 
increase of 69 GW of wind capacity, 63 GW of natural gas capacity, and 
59 GW of utility-scale solar capacity. Additionally, a net summer 
capacity of 30 GW of DER solar were added from 2015 to 2022.
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    \116\ This includes generating capacity at EGUs primarily 
operated to supply electricity to the grid and combined heat and 
power (CHP) facilities classified as Independent Power Producers and 
excludes generating capacity at commercial and industrial facilities 
that does not operate primarily as an EGU. Natural gas information 
reflects data for all generating units using natural gas as the 
primary fossil heat source unless otherwise stated. This includes 
combined cycle, simple cycle, steam, and miscellaneous (<1 percent).
    \117\ U.S. Energy Information Administration (EIA). Electric 
Power Annuals 2010 (Tables 1.1.A and 1.1.B) and 2022 (Tables 4.2.A 
and 4.2.B).
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b. Current Structure of Coal-Fired Generation
    Although much of the fleet of coal-fired steam generating units has 
historically operated as base load, there can be notable differences in 
design and operation across various facilities. For example, coal-fired 
steam generating units smaller than 100 MW comprise 18 percent of the 
total number of coal-fired units, but only 2 percent of total coal-
fired capacity.\118\ Moreover, average annual capacity factors for 
coal-fired steam generating units have declined from 74 to 50 percent 
since 2007.\119\ These declining capacity factors indicate that a 
larger share of units are operating in non-base load fashion largely 
because they are no longer cost-competitive in many hours of the year.
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    \118\ U.S. Environmental Protection Agency. National Electric 
Energy Data System (NEEDS) v7. December 2023. <a href="https://www.epa.gov/power-sector-modeling/national-electric-energy-data-system-needs">https://www.epa.gov/power-sector-modeling/national-electric-energy-data-system-needs</a>.
    \119\ U.S. Energy Information Administration (EIA). Electric 
Power Annual 2021, table 1.2.
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    Older power plants also tend to become uneconomic over time as they 
become more costly to maintain and operate,\120\ especially when 
competing for dispatch against newer and more efficient generating 
technologies that have lower operating costs. The average coal-fired 
power plant that retired between 2015 and 2022 was more than 50 years 
old, and 65 percent of the remaining fleet of coal-fired steam 
generating units will be 50 years old or more within a decade.\121\ To 
further illustrate this trend, the existing coal-fired steam generating 
units older than 40 years represent 71 percent (129 GW) \122\ of the 
total remaining capacity. In fact, more than half (100 GW) of the coal-
fired steam generating units still operating have already announced 
retirement dates prior to 2039 or conversion to gas-fired units by the

[[Page 39818]]

same year.\123\ As discussed later in this section, projections 
anticipate that this trend will continue.
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    \120\ U.S. Energy Information Administration (EIA). U.S. coal 
plant retirements linked to plants with higher operating costs. 
December 2019. <a href="https://www.eia.gov/todayinenergy/detail.php?id=42155">https://www.eia.gov/todayinenergy/detail.php?id=42155</a>.
    \121\ eGRID 2020 (January 2022 release from EPA eGRID website). 
Represents data from generators that came online between 1950 and 
2020 (inclusive); a 71-year period. Full eGRID data includes 
generators that came online as far back as 1915.
    \122\ U.S. Energy Information Administration (EIA). Electric 
Generators Inventory, Form-860M, Inventory of Operating Generators 
and Inventory of Retired Generators. August 2022. <a href="https://www.eia.gov/electricity/data/eia860m/">https://www.eia.gov/electricity/data/eia860m/</a>.
    \123\ U.S. Environmental Protection Agency. National Electric 
Energy Data System (NEEDS) v6. October 2022. <a href="https://www.epa.gov/power-sector-modeling/national-electric-energy-data-system-needs">https://www.epa.gov/power-sector-modeling/national-electric-energy-data-system-needs</a>.
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    The reduction in coal-fired generation by electric utilities is 
also evident in data for annual U.S. coal production, which reflects 
reductions in international demand as well. In 2008, annual coal 
production peaked at nearly 1,172 million short tons (MMst) followed by 
sharp declines in 2015 and 2020.\124\ In 2015, less than 900 MMst were 
produced, and in 2020, the total dropped to 535 MMst, the lowest output 
since 1965. Following the pandemic, in 2022, annual coal production had 
increased to 594 MMst. For additional analysis of the coal-fired steam 
generation fleet, see the final TSD, Power Sector Trends included in 
the docket for this rulemaking.
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    \124\ U.S. Energy Information Administration (EIA). (October 
2023). Annual Coal Report 2022. <a href="https://www.eia.gov/coal/annual/pdf/acr.pdf">https://www.eia.gov/coal/annual/pdf/acr.pdf</a>.
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    Notwithstanding these trends, in 2022, coal-fired energy sources 
were still responsible for 50 percent of CO<INF>2</INF> emissions from 
the electric power sector.\125\
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    \125\ U.S. Energy Information Administration (EIA). U.S. 
CO<INF>2</INF> emissions from energy consumption by source and 
sector, 2022. <a href="https://www.eia.gov/totalenergy/data/monthly/pdf/flow/CO2_emissions_2022.pdf">https://www.eia.gov/totalenergy/data/monthly/pdf/flow/CO2_emissions_2022.pdf</a>.
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4. Natural Gas-Fired Generation: Historical Trends and Current 
Structure
a. Historical Trends in Natural Gas-Fired Generation
    There has been significant expansion of the natural gas-fired EGU 
fleet since 2000, coinciding with efficiency improvements of combustion 
turbine technologies, increased availability of natural gas, increased 
demand for flexible generation to support the expanding capacity of 
variable energy resources, and declining costs for all three elements. 
According to data from EIA, annual capacity additions for natural gas-
fired EGUs peaked between 2000 and 2006, with more than 212 GW added to 
the grid during this period (about 35 GW per year). Of this total, 
approximately 147 GW (70 percent) were combined cycle capacity and 65 
GW were simple cycle capacity.\126\ From 2007 to 2022, more than 132 GW 
of capacity were constructed and approximately 77 percent of that total 
were combined cycle EGUs. This figure represents an average of almost 
8.8 GW of new combustion turbine generation capacity per year. In 2022, 
the net summer capacity of combustion turbine EGUs totaled 419 GW, with 
289 GW being combined cycle generation and 130 GW being simple cycle 
generation.
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    \126\ U.S. Energy Information Administration (EIA). Electric 
Generators Inventory, Form EIA-860M, Inventory of Operating 
Generators and Inventory of Retired Generators, July 2022. <a href="https://www.eia.gov/electricity/data/eia860m/">https://www.eia.gov/electricity/data/eia860m/</a>.
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    This trend away from electricity generation using coal-fired EGUs 
to natural gas-fired turbine EGUs is also reflected in comparisons of 
annual capacity factors, sizes, and ages of affected EGUs. For example, 
the average annual capacity factors for natural gas-fired units 
increased from 28 to 38 percent between 2010 and 2022. And compared 
with the fleet of coal-fired steam generating units, the natural gas 
fleet is generally smaller and newer. While 67 percent of the coal-
fired steam generating unit fleet capacity is over 500 MW per unit, 75 
percent of the gas fleet is between 50 and 500 MW per unit. In terms of 
the age of the generating units, nearly 50 percent of the natural gas 
capacity has been in service less than 15 years.\127\
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    \127\ National Electric Energy Data System (NEEDS) v.6.
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b. Current Structure of Natural Gas-Fired Generation
    In the lower 48 states, most combustion turbine EGUs burn natural 
gas, and some have the capability to fire distillate oil as backup for 
periods when natural gas is not available, such as when residential 
demand for natural gas is high during the winter. Areas of the country 
without access to natural gas often use distillate oil or some other 
locally available fuel. Combustion turbines have the capability to burn 
either gaseous or liquid fossil fuels, including but not limited to 
kerosene, naphtha, synthetic gas, biogases, liquified natural gas 
(LNG), and hydrogen.
    Over the past 20 years, advances in hydraulic fracturing (i.e., 
fracking) and horizontal drilling techniques have opened new regions of 
the U.S. to gas exploration. As the production of natural gas has 
increased, the annual average price has declined during the same 
period, leading to more natural gas-fired combustion turbines.\128\ 
Natural gas net generation increased 181 percent in the past two 
decades, from 601 thousand gigawatt-hours (GWh) in 2000 to 1,687 
thousand GWh in 2022. For additional analysis of natural gas-fired 
generation, see the final TSD, Power Sector Trends included in the 
docket for this rulemaking.
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    \128\ U.S. Energy Information Administration (EIA). Natural Gas 
Annual, September 2021. <a href="https://www.eia.gov/energyexplained/natural-gas/prices.php">https://www.eia.gov/energyexplained/natural-gas/prices.php</a>.
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E. The Legislative, Market, and State Law Context

1. Recent Legislation Impacting the Power Sector
    On November 15, 2021, President Biden signed the IIJA \129\ (also 
known as the Bipartisan Infrastructure Law), which allocated more than 
$65 billion in funding via grant programs, contracts, cooperative 
agreements, credit allocations, and other mechanisms to develop and 
upgrade infrastructure and expand access to clean energy technologies. 
Specific objectives of the legislation are to improve the nation's 
electricity transmission capacity, pipeline infrastructure, and 
increase the availability of low-GHG fuels. Some of the IIJA programs 
\130\ that will impact the utility power sector include more than $20 
billion to build and upgrade the nation's electric grid, up to $6 
billion in financial support for existing nuclear reactors that are at 
risk of closing, and more than $700 million for upgrades to the 
existing hydroelectric fleet. The IIJA established the Carbon Dioxide 
Transportation Infrastructure Finance and Innovation Program to provide 
flexible Federal loans and grants for building CO<INF>2</INF> pipelines 
designed with excess capacity, enabling integrated carbon capture and 
geologic storage. The IIJA also allocated $21.5 billion to fund new 
programs to support the development, demonstration, and deployment of 
clean energy technologies, such as $8 billion for the development of 
regional clean hydrogen hubs and $7 billion for the development of 
carbon management technologies, including regional direct air capture 
hubs, carbon capture large-scale pilot projects for development of 
transformational technologies, and carbon capture commercial-scale 
demonstration projects to improve efficiency and effectiveness. Other 
clean energy technologies with IIJA and IRA funding include industrial 
demonstrations, geologic sequestration, grid-scale energy storage, and 
advanced nuclear reactors.
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    \129\ <a href="https://www.congress.gov/bill/117th-congress/house-bill/3684/text">https://www.congress.gov/bill/117th-congress/house-bill/3684/text</a>.
    \130\ <a href="https://www.whitehouse.gov/wp-content/uploads/2022/05/BUILDING-A-BETTER-AMERICA-V2.pdf">https://www.whitehouse.gov/wp-content/uploads/2022/05/BUILDING-A-BETTER-AMERICA-V2.pdf</a>.
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    The IRA, which President Biden signed on August 16, 2022,\131\ has 
the potential for even greater impacts on the electric power sector. 
Energy Security and Climate Change programs in the

[[Page 39819]]

IRA covering grant funding and tax incentives provide significant 
investments in low and non GHG-emitting generation. For example, one of 
the conditions set by Congress for the expiration of the Clean 
Electricity Production Tax Credits of the IRA, found in section 13701, 
is a 75 percent reduction in GHG emissions from the power sector below 
2022 levels. The IRA also contains the Low Emission Electricity Program 
(LEEP) with funding provided to the EPA with the objective to reduce 
GHG emissions from domestic electricity generation and use through 
promotion of incentives, tools to facilitate action, and use of CAA 
regulatory authority. In particular, CAA section 135, added by IRA 
section 60107, requires the EPA to conduct an assessment of the GHG 
emission reductions expected to occur from changes in domestic 
electricity generation and use through fiscal year 2031 and, further, 
provides the EPA $18 million ``to ensure that reductions in [GHG] 
emissions are achieved through use of the existing authorities of [the 
Clean Air Act], incorporating the assessment. . . .'' CAA section 
135(a)(6).
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    \131\ <a href="https://www.congress.gov/bill/117th-congress/house-bill/5376/text">https://www.congress.gov/bill/117th-congress/house-bill/5376/text</a>.
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    The IRA's provisions also demonstrate an intent to support 
development and deployment of low-GHG emitting technologies in the 
power sector through a broad array of additional tax credits, loan 
guarantees, and public investment programs. Particularly relevant for 
these final actions, these provisions are aimed at reducing emissions 
of GHGs from new and existing generating assets, with tax credits for 
CCUS and clean hydrogen production, providing a pathway for the use of 
coal and natural gas as part of a low-GHG electricity grid.
    To assist states and utilities in their decarbonizing efforts, and 
most germane to these final actions, the IRA increased the tax credit 
incentives for capturing and storing CO<INF>2</INF>, including from 
industrial sources, coal-fired steam generating units, and natural gas-
fired stationary combustion turbines. The increase in credit values, 
found in section 13104 (which revises IRC section 45Q), is 70 percent, 
equaling $85/metric ton for CO<INF>2</INF> captured and securely stored 
in geologic formations and $60/metric ton for CO<INF>2</INF> captured 
and utilized or securely stored incidentally in conjunction with 
EOR.\132\ The CCUS incentives include 12 years of credits that can be 
claimed at the higher credit value beginning in 2023 for qualifying 
projects. These incentives will significantly cut costs and are 
expected to accelerate the adoption of CCS in the utility power and 
other industrial sectors. Specifically for the power sector, the IRA 
requires that a qualifying carbon capture facility have a 
CO<INF>2</INF> capture design capacity of not less than 75 percent of 
the baseline CO<INF>2</INF> production of the unit and that 
construction must begin before January 1, 2033. Tax credits under IRC 
section 45Q can be combined with some other tax credits, in some 
circumstances, and with state-level incentives, including California's 
low carbon fuel standard, which is a market-based program with fuel-
specific carbon intensity benchmarks.\133\ The magnitude of this 
incentive is driving investment and announcements, evidenced by the 
increased number of permit applications for geologic 
sequestration.\134\
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    \132\ 26 U.S.C. 45Q. Note, qualified facilities must meet 
prevailing wage and apprenticeship requirements to be eligible for 
the full value of the tax credit.
    \133\ Global CCS Institute. (2019). The LCFS and CCS Protocol: 
An Overview for Policymakers and Project Developers. Policy report. 
<a href="https://www.globalccsinstitute.com/wp-content/uploads/2019/05/LCFS-and-CCS-Protocol_digital_version-2.pdf">https://www.globalccsinstitute.com/wp-content/uploads/2019/05/LCFS-and-CCS-Protocol_digital_version-2.pdf</a>.
    \134\ EPA. (2024). Current Class VI Projects under Review at 
EPA. <a href="https://www.epa.gov/uic/current-class-vi-projects-under-review-epa">https://www.epa.gov/uic/current-class-vi-projects-under-review-epa</a>.
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    The new provisions in section 13204 (IRC section 45V) codify 
production tax credits for `clean hydrogen' as defined in the 
provision. The value of the credits earned by a project is tiered (four 
different tiers) and depends on the estimated GHG emissions of the 
hydrogen production process as defined in the statute. The credits 
range from $3/kg H<INF>2</INF> for less than 0.45 kilograms of 
CO<INF>2</INF>-equivalent emitted per kilogram of low-GHG hydrogen 
produced (kg CO<INF>2</INF>e/kg H<INF>2</INF>) down to $0.6/kg 
H<INF>2</INF> for 2.5 to 4.0 kg CO<INF>2</INF>e/kg H<INF>2</INF> 
(assuming wage and apprenticeship requirements are met). Projects with 
production related GHG emissions greater than 4.0 kg CO<INF>2</INF>e/kg 
H<INF>2</INF> are not eligible. Future costs for clean hydrogen 
produced using renewable energy are anticipated to through 2030 due to 
these tax incentives and concurrent scaling up of manufacturing and 
deployment of clean hydrogen production facilities.
    Both IRC section 45Q and IRC section 45V are eligible for 
additional provisions that increase the value and usability of the 
credits. Certain tax-exempt entities, such as electric co-operatives, 
may elect direct payment for the full 12- or 10-year lifetime of the 
credits to monetize the credits directly as cash refunds rather than 
through tax equity transactions. Tax-paying entities may elect to have 
direct payment of IRC section 45Q or 45V credits for 5 consecutive 
years. Tax-paying entities may also elect to transfer credits to 
unrelated taxpayers, enabling direct monetization of the credits again 
without relying on tax equity transactions.
    In addition to provisions such as 45Q that allow for the use of 
fossil-generating assets in a low-GHG future, the IRA also includes 
significant incentives to deploy clean energy generation. For instance, 
the IRA provides an additional 10 percent in production tax credit 
(PTC) and investment tax credit (ITC) bonuses for clean energy projects 
located in energy communities with historic employment and tax bases 
related to fossil fuels.\135\ The IRA's Energy Infrastructure 
Reinvestment Program also provides $250 billion for the DOE to finance 
loan guarantees that can be used to reduce both the cost of retiring 
existing fossil assets and of replacement generation for those assets, 
including updating operating energy infrastructure with emissions 
control technologies.\136\ As a further example, the Empowering Rural 
America (New ERA) Program provides rural electric cooperatives with 
funds that can be used for a variety of purposes, including ``funding 
for renewable and zero emissions energy systems that eliminate aging, 
obsolete or expensive infrastructure'' or that allow rural cooperatives 
to ``change [their] purchased-power mixes to support cleaner 
portfolios, manage stranded assets and boost [the] transition to clean 
energy.'' \137\ The $9.7 billion New ERA program represents the single 
largest investment in rural energy systems since the Rural 
Electrification Act of 1936.\138\
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    \135\ U.S. Department of the Treasury. (April 4, 2023). Treasury 
Releases Guidance to Drive Investment to Coal Communities. Press 
release. <a href="https://home.treasury.gov/news/press-releases/jy1383">https://home.treasury.gov/news/press-releases/jy1383</a>.
    \136\ Fong, C., Posner, D., Varadarajan, U. (February 16, 2024). 
The Energy Infrastructure Reinvestment Program: Federal financing 
for an equitable, clean economy. Case studies from Missouri and 
Iowa. Rocky Mountain Institute (RMI). <a href="https://rmi.org/the-energy-infrastructure-reinvestment-program-federal-financing-for-an-equitable-clean-economy/">https://rmi.org/the-energy-infrastructure-reinvestment-program-federal-financing-for-an-equitable-clean-economy/</a>.
    \137\ U.S. Department of Agriculture (USDA). Empowering Rural 
America New ERA Program. <a href="https://www.rd.usda.gov/programs-services/electric-programs/empowering-rural-america-new-era-program">https://www.rd.usda.gov/programs-services/electric-programs/empowering-rural-america-new-era-program</a>.
    \138\ Rocky Mountain Institute (RMI). (October 4, 2023). USDA 
$9.7B Rural Community Clean Energy Program Receives 150+ Letters of 
Interest. Press release. <a href="https://rmi.org/press-release/usda-9-7b-rural-community-clean-energy-program-receives-150-letters-of-interest/">https://rmi.org/press-release/usda-9-7b-rural-community-clean-energy-program-receives-150-letters-of-interest/</a>.
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    On September 12, 2023, the EPA released a report assessing the 
impact of the IRA on the power sector. Modeling results showed that 
economy-wide CO<INF>2</INF> emissions are lower under the IRA. The

[[Page 39820]]

results from the EPA's analysis of an array of multi-sector and 
electric sector modeling efforts show that a wide range of emissions 
reductions are possible. The IRA spurs CO<INF>2</INF> emissions 
reductions from the electric power sector of 49 to 83 percent below 
2005 levels in 2030. This finding reflects diversity in how the models 
represent the IRA, the assumptions the models use, and fundamental 
differences in model structures.\139\
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    \139\ U.S. Environmental Protection Agency (EPA). (September 
2023). Electricity Sector Emissions Impacts of the Inflation 
Reduction Act. <a href="https://www.epa.gov/system/files/documents/2023-09/Electricity_Emissions_Impacts_Inflation_Reduction_Act_Report_EPA-FINAL.pdf">https://www.epa.gov/system/files/documents/2023-09/Electricity_Emissions_Impacts_Inflation_Reduction_Act_Report_EPA-FINAL.pdf</a>.
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    In determining the CAA section 111 emission limitations that are 
included in these final actions, the EPA did not consider many of the 
technologies that receive investment under recent Federal legislation. 
The EPA's determination of the BSER focused on ``measures that improve 
the pollution performance of individual sources,'' \140\ not generation 
technologies that entities could employ as alternatives to fossil fuel-
fired EGUs. However, these overarching incentives and policies are 
important context for this rulemaking and influence where control 
technologies can be feasibly and cost-reasonably deployed, as well as 
how owners and operators of EGUs may respond to the requirements of 
these final actions.
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    \140\ West Virginia v. EPA, 597 U.S. at 734.
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2. Commitments by Utilities To Reduce GHG Emissions
    Integrated resource plans (IRPs) are filed by public utilities and 
demonstrate how utilities plan to meet future forecasted energy demand 
while ensuring reliable and cost-effective service. In developing these 
rules, the EPA reviewed filed IRPs of companies that have publicly 
committed to reducing their GHGs. These IRPs demonstrate a range of 
strategies that public utilities are planning to adopt to reduce their 
GHGs, independent of these final actions. These strategies include 
retiring aging coal-fired steam generating EGUs and replacing them with 
a combination of renewable resources, energy storage, other non-
emitting technologies, and natural gas-fired combustion turbines, and 
reducing GHGs from their natural gas-fired assets through a combination 
of CCS and reduced utilization. To affirm these findings, according to 
EIA, as of 2022 there are no new coal-fired EGUs in development. This 
section highlights recent actions and announced plans of many utilities 
across the industry to reduce GHGs from their fleets. Indeed, 50 power 
producers that are members of the Edison Electric Institute (EEI) have 
announced CO<INF>2</INF> reduction goals, two-thirds of which include 
net-zero carbon emissions by 2050.\141\ The members of the Energy 
Strategies Coalition, a group of companies that operate and manage 
electricity generation facilities, as well as electricity and natural 
gas transmission and distribution systems, likewise are focused on 
investments to reduce carbon dioxide emissions from the electricity 
sector.\142\ This trend is not unique. Smaller utilities, rural 
electric cooperatives, and municipal entities are also contributing to 
these changes.
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    \141\ See Comments of Edison Electric Institute to EPA's Pre-
Proposal Docket on Greenhouse Gas Regulations for Fossil Fuel-fired 
Power Plants, Document ID No. EPA-HQ-OAR-2022-0723-0024, November 
18, 2022 (``Fifty EEI members have announced forward-looking carbon 
reduction goals, two-third of which include a net-zero by 2050 or 
earlier equivalent goal, and members are routinely increasing the 
ambition or speed of their goals or altogether transforming them 
into net-zero goals.'').
    \142\ Energy Strategy Coalition Comments on EPA's proposed New 
Source Performance Standards for Greenhouse Gas Emissions From New, 
Modified, and Reconstructed Fossil Fuel-Fired Electric Generating 
Units; Emission Guidelines for Greenhouse Gas Emissions From 
Existing Fossil Fuel-Fired Electric Generating Units; and Repeal of 
the Affordable Clean Energy Rule, Document ID No. EPA-HQ-OAR-2023-
0072-0672, August 14, 2023.
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    Many electric utilities have publicly announced near- and long-term 
emission reduction commitments independent of these final actions. The 
Smart Electric Power Alliance demonstrates that the geographic 
footprint of commitments for 100 percent renewable, net-zero, or other 
carbon emission reductions by 2050 made by utilities, their parent 
companies, or in response to a state clean energy requirement, covers 
portions of 47 states and includes 80 percent of U.S. customer 
accounts.\143\ According to this same source, 341 utilities in 26 
states have similar commitments by 2040. Additional detail about 
emission reduction commitments from major utilities is provided in 
section 2.2 of the RIA and in the final TSD, Power Sector Trends.
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    \143\ Smart Electric Power Alliance Utility Carbon Tracker. 
<a href="https://sepapower.org/utility-transformation-challenge/utility-carbon-reduction-tracker/">https://sepapower.org/utility-transformation-challenge/utility-carbon-reduction-tracker/</a>.
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3. State Actions To Reduce Power Sector GHG Emissions
    States across the country have taken the lead in efforts to reduce 
GHG emissions from the power sector. As of mid-2023, 25 states had made 
commitments to reduce economy-wide GHG emissions consistent with the 
goals of the Paris Agreement, including reducing GHG emissions by 50 to 
52 percent by 2030.<SUP>144 145 146</SUP> These actions include 
legislation to decarbonize state power systems as well as commitments 
that require utilities to expand renewable and clean energy production 
through the adoption of renewable portfolio standards (RPS) and clean 
energy standards (CES).
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    \144\ Cao, L., Brindle., T., Schneer, K., and DeGolia, A. 
(December 2023). Turning Climate Commitments into Results: 
Evaluating Updated 2023 Projections vs. State Climate Targets. 
Environmental Defense Fund (EDF). <a href="https://www.edf.org/sites/default/files/2023-11/EDF-State-Emissions-Gap-December-2023.pdf">https://www.edf.org/sites/default/files/2023-11/EDF-State-Emissions-Gap-December-2023.pdf</a>.
    \145\ United Nations Framework Convention on Climate Change. 
What is the Paris Agreement? <a href="https://unfccc.int/process-and-meetings/the-paris-agreement">https://unfccc.int/process-and-meetings/the-pari

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Indexed from Federal Register on May 9, 2024.

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