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Proposed Rule2023-10047

Revisions and Confidentiality Determinations for Data Elements Under the Greenhouse Gas Reporting Rule

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Published

May 22, 2023

Issuing agencies

Environmental Protection Agency

Abstract

The EPA is issuing this supplemental proposal that would amend specific provisions in the Greenhouse Gas Reporting Rule to improve the quality and consistency of the rule by providing for the collection of improved data that would better inform and be relevant to a wide variety of Clean Air Act provisions that the EPA carries out. The EPA recently evaluated the requirements of the Greenhouse Gas Reporting Rule to identify areas of improvement, including updates to the existing calculation, recordkeeping, and reporting requirements, and requested information for collection of additional data to understand new source categories in a proposed rule (June 21, 2022). In this notification, the EPA is proposing additional amendments to the Greenhouse Gas Reporting Rule, including updates to the General Provisions to reflect revised global warming potentials, and is proposing to require reporting of greenhouse gas data from additional sectors--specifically energy consumption; coke calcining; ceramics production; calcium carbide production; and caprolactam, glyoxal, and glyoxylic acid production. The EPA is also proposing additional revisions that would improve implementation of the Greenhouse Gas Reporting Rule, such as updates to emissions calculation methodologies; revisions to reporting requirements to improve verification of reported data and the accuracy of the data collected; and other minor technical amendments, corrections, or clarifications. The EPA intends to consider the information received in response to this supplemental proposal prior to finalizing the amendments to the Greenhouse Gas Reporting Rule proposed on June 21, 2022. This action also proposes to establish and amend confidentiality determinations for the reporting of certain data elements to be added or substantially revised in these proposed amendments.

Full Text

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[Federal Register Volume 88, Number 98 (Monday, May 22, 2023)]
[Proposed Rules]
[Pages 32852-32947]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-10047]

[[Page 32851]]

Vol. 88

Monday,

No. 98

May 22, 2023

Part III

Environmental Protection Agency

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40 CFR Part 98

Revisions and Confidentiality Determinations for Data Elements Under
the Greenhouse Gas Reporting Rule; Proposed Rule

Federal Register / Vol. 88 , No. 98 / Monday, May 22, 2023 / Proposed
Rules

[[Page 32852]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 98

[EPA-HQ-OAR-2019-0424; FRL-7230-03-OAR]
RIN 2060-AU35

Revisions and Confidentiality Determinations for Data Elements
Under the Greenhouse Gas Reporting Rule

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental notice of proposed rulemaking.

-----------------------------------------------------------------------

SUMMARY: The EPA is issuing this supplemental proposal that would amend
specific provisions in the Greenhouse Gas Reporting Rule to improve the
quality and consistency of the rule by providing for the collection of
improved data that would better inform and be relevant to a wide
variety of Clean Air Act provisions that the EPA carries out. The EPA
recently evaluated the requirements of the Greenhouse Gas Reporting
Rule to identify areas of improvement, including updates to the
existing calculation, recordkeeping, and reporting requirements, and
requested information for collection of additional data to understand
new source categories in a proposed rule (June 21, 2022). In this
notification, the EPA is proposing additional amendments to the
Greenhouse Gas Reporting Rule, including updates to the General
Provisions to reflect revised global warming potentials, and is
proposing to require reporting of greenhouse gas data from additional
sectors--specifically energy consumption; coke calcining; ceramics
production; calcium carbide production; and caprolactam, glyoxal, and
glyoxylic acid production. The EPA is also proposing additional
revisions that would improve implementation of the Greenhouse Gas
Reporting Rule, such as updates to emissions calculation methodologies;
revisions to reporting requirements to improve verification of reported
data and the accuracy of the data collected; and other minor technical
amendments, corrections, or clarifications. The EPA intends to consider
the information received in response to this supplemental proposal
prior to finalizing the amendments to the Greenhouse Gas Reporting Rule
proposed on June 21, 2022. This action also proposes to establish and
amend confidentiality determinations for the reporting of certain data
elements to be added or substantially revised in these proposed
amendments.

DATES:
Comments. Comments must be received on or before July 21, 2023.
Comments on the information collection provisions submitted to the
Office of Management and Budget (OMB) under the Paperwork Reduction Act
(PRA) are best assured of consideration by OMB if OMB receives a copy
of your comments on or before June 21, 2023.
Public hearing. The EPA does not plan to conduct a public hearing
unless requested. If anyone contacts us requesting a public hearing on
or before May 30, 2023, we will hold a virtual public hearing. See
SUPPLEMENTARY INFORMATION for information on requesting and registering
for a public hearing.

ADDRESSES:
Comments. You may submit comments, identified by Docket Id. No.
EPA-HQ-OAR-2019-0424, by any of the following methods:
Federal eRulemaking Portal: <a href="http://www.regulations.gov">www.regulations.gov</a> (our preferred
method). Follow the online instructions for submitting comments.
Mail: U.S. Environmental Protection Agency, EPA Docket Center, Air
and Radiation Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW,
Washington, DC 20460.
Hand Delivery or Courier (by scheduled appointment only): EPA
Docket Center, WJC West Building, Room 3334, 1301 Constitution Avenue
NW, Washington, DC 20004. The Docket Center's hours of operations are
8:30 a.m.-4:30 p.m., Monday-Friday (except Federal holidays)
Instructions: All submissions received must include the Docket Id.
No. for this proposed rulemaking. Comments received may be posted
without change to <a href="http://www.regulations.gov/">www.regulations.gov/</a>, including any personal
information provided. For detailed instructions on sending comments and
additional information on the rulemaking process, see the ``Public
Participation'' heading of the SUPPLEMENTARY INFORMATION section of
this document.
The virtual hearing, if requested, will be held using an online
meeting platform, and the EPA will provide information on its website
(<a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a>) regarding how to register and access the
hearing. Refer to the SUPPLEMENTARY INFORMATION section for additional
information.

FOR FURTHER INFORMATION CONTACT: Jennifer Bohman, Climate Change
Division, Office of Atmospheric Programs (MC-6207A), Environmental
Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460;
telephone number: (202) 343-9548; email address: <a href="/cdn-cgi/l/email-protection#0d4a454a5f687d627f7964636a4d687d6c236a627b">[email&#160;protected]</a>.
For technical information, please go to the Greenhouse Gas Reporting
Program (GHGRP) website, <a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a>. To submit a
question, select Help Center, followed by ``Contact Us.''
World wide web (WWW). In addition to being available in the docket,
an electronic copy of this proposal will also be available through the
WWW. Following the Administrator's signature, a copy of this proposed
rule will be posted on the EPA's GHGRP website at <a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a>.

SUPPLEMENTARY INFORMATION:
Written comments. Submit your comments, identified by Docket Id.
No. EPA-HQ-OAR-2019-0424, at <a href="http://www.regulations.gov">www.regulations.gov</a> (our preferred
method), or the other methods identified in the ADDRESSES section. Once
submitted, comments cannot be edited or removed from the docket. The
EPA may publish any comment received to its public docket. Do not
submit to the EPA's docket at <a href="http://www.regulations.gov">www.regulations.gov</a> any information you
consider to be confidential business information (CBI), proprietary
business information (PBI), or other information whose disclosure is
restricted by statute. Multimedia submissions (audio, video, etc.) must
be accompanied by a written comment. The written comment is considered
the official comment and should include discussion of all points you
wish to make. The EPA will generally not consider comments or comment
contents located outside of the primary submission (i.e., on the web,
cloud, or other file sharing system). Please visit <a href="http://www.epa.gov/dockets/commenting-epa-dockets">www.epa.gov/dockets/commenting-epa-dockets</a> for additional submission methods; the full EPA
public comment policy; information about CBI, PBI, or multimedia
submissions, and general guidance on making effective comments.
Participation in virtual public hearing. To request a virtual
public hearing, please contact the person listed in the following FOR
FURTHER INFORMATION CONTACT section by May 30, 2023. If requested, the
virtual hearing will be held on June 6, 2023. The hearing will convene
at 9 a.m. Eastern Time (ET) and will conclude at 3 p.m. ET. The EPA may
close the hearing 15 minutes after the last pre-registered speaker has
testified if there are no additional speakers. The EPA will provide
further information about the hearing on its website (<a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a>) if a hearing is requested.
If a public hearing is requested, the EPA will begin pre-
registering speakers

[[Page 32853]]

for the hearing no later than one business day after a request has been
received. To register to speak at the virtual hearing, please use the
online registration form available at <a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a> or
contact us by email at <a href="/cdn-cgi/l/email-protection#73343b342116031c01071a1d14331603125d141c05">[email&#160;protected]</a>. The last day to pre-
register to speak at the hearing will be June 5, 2023. On June 5, 2023,
the EPA will post a general agenda that will list pre-registered
speakers in approximate order at: <a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a>.
The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule.
Each commenter will have 5 minutes to provide oral testimony. The
EPA encourages commenters to provide the EPA with a copy of their oral
testimony electronically (via email) by emailing it to
<a href="/cdn-cgi/l/email-protection#e8afa0afba8d98879a9c81868fa88d9889c68f879e">[email&#160;protected]</a>. The EPA also recommends submitting the text of
your oral testimony as written comments to the rulemaking docket.
The EPA may ask clarifying questions during the oral presentations
but will not respond to the presentations at that time. Written
statements and supporting information submitted during the comment
period will be considered with the same weight as oral testimony and
supporting information presented at the public hearing.
Please note that any updates made to any aspect of the hearing will
be posted online at <a href="http://www.epa.gov/ghgreporting">www.epa.gov/ghgreporting</a>. While the EPA expects the
hearing to go forward as set forth above, please monitor our website or
contact us by email at <a href="/cdn-cgi/l/email-protection#a8efe0effacdd8c7dadcc1c6cfe8cdd8c986cfc7de">[email&#160;protected]</a> to determine if there are
any updates. The EPA does not intend to publish a document in the
Federal Register announcing updates.
If you require the services of an interpreter or special
accommodation such as audio description, please pre-register for the
hearing with the public hearing team and describe your needs by May 30,
2023. The EPA may not be able to arrange accommodations without
advanced notice.
Regulated entities. This is a proposed regulation. If finalized,
these proposed revisions would affect certain entities that must submit
annual greenhouse gas (GHG) reports under the GHGRP (40 CFR part 98).
These are proposed amendments to existing regulations. If finalized,
these amended regulations would also affect owners or operators of
certain industry sectors that are direct emitters of GHGs. Regulated
categories and entities include, but are not limited to, those listed
in Table 1 of this preamble:

Table 1--Examples of Affected Entities by Category
------------------------------------------------------------------------
North American Examples of
Industry facilities that may
Category Classification be subject to part
System (NAICS) 98:
------------------------------------------------------------------------
Adipic Acid Production........ 325199 All other basic
organic chemical
manufacturing:
Adipic acid
manufacturing.
Aluminum Production........... 331313 Primary aluminum
production
facilities.
Ammonia Manufacturing......... 325311 Anhydrous ammonia
manufacturing
facilities.
Calcium Carbide Production.... 325180 Other basic inorganic
chemical
manufacturing:
calcium carbide
manufacturing.
Carbon Dioxide Enhanced Oil 211120 Oil and gas
Recovery Projects. extraction projects
using carbon dioxide
enhanced oil
recovery.
Caprolactam, Glyoxal, and 325199 All other basic
Glyoxylic Acid Production. organic chemical
manufacturing.
Cement Production............. 327310 Cement manufacturing.
Ceramics Manufacturing........ 327110 Pottery, ceramics,
and plumbing fixture
manufacturing.
327120 Clay building
material and
refractories
manufacturing.
Coke Calcining................ 299901 Coke; coke,
petroleum; coke,
calcined petroleum.
Electronics Manufacturing..... 334111 Microcomputers
manufacturing
facilities.
334413 Semiconductor,
photovoltaic (PV)
(solid-state) device
manufacturing
facilities.
334419 Liquid crystal
display (LCD) unit
screens
manufacturing
facilities;
Microelectromechanic
al (MEMS)
manufacturing
facilities.
Electrical Equipment 33531 Power transmission
Manufacture or Refurbishment. and distribution
switchgear and
specialty
transformers
manufacturing
facilities.
Electricity generation units 221112 Electric power
that report through 40 CFR generation, fossil
part 75. fuel (e.g., coal,
oil, gas).
Electrical Equipment Use...... 221121 Electric bulk power
transmission and
control facilities.
Electrical transmission and 33361 Engine, Turbine, and
distribution equipment Power Transmission
manufacture or refurbishment. Equipment
Manufacturing.
Ferroalloy Production......... 331110 Ferroalloys
manufacturing.
Fluorinated Greenhouse Gas 325120 Industrial gases
Production. manufacturing
facilities.
Geologic Sequestration........ NA CO2 geologic
sequestration sites.
Glass Production.............. 327211 Flat glass
manufacturing
facilities.
327213 Glass container
manufacturing
facilities.
327212 Other pressed and
blown glass and
glassware
manufacturing
facilities.
HCFC-22 Production............ 325120 Industrial gas
manufacturing:
Hydrochlorofluorocar
bon (HCFC) gases
manufacturing.
HFC-23 destruction processes 325120 Industrial gas
that are not collocated with manufacturing:
a HCFC-22 production facility Hydrofluorocarbon
and that destroy more than (HFC) gases
2.14 metric tons of HFC-23 manufacturing.
per year.
Hydrogen Production........... 325120 Hydrogen
manufacturing
facilities.
Industrial Waste Landfill..... 562212 Solid waste landfill.
Industrial Wastewater 221310 Water treatment
Treatment. plants.
Injection of Carbon Dioxide... 211 Oil and gas
extraction.
Iron and Steel Production..... 333110 Integrated iron and
steel mills, steel
companies, sinter
plants, blast
furnaces, basic
oxygen process
furnace (BOPF)
shops.
Lead Production............... 331 Primary metal
manufacturing.
Lime Manufacturing............ 327410 Lime production.
Magnesium Production.......... 331410 Nonferrous metal
(except aluminum)
smelting and
refining: Magnesium
refining, primary.
Nitric Acid Production........ 325311 Nitrogenous
fertilizer
manufacturing:
Nitric acid
manufacturing.
Petroleum and Natural Gas 486210 Pipeline
Systems. transportation of
natural gas.

[[Page 32854]]

221210 Natural gas
distribution
facilities.
211120 Crude petroleum
extraction.
211130 Natural gas
extraction.
Petrochemical Production...... 324110 Petrochemicals made
in petroleum
refineries.
Petroleum Refineries.......... 324110 Petroleum refineries.
Phosphoric Acid Production.... 325312 Phosphatic fertilizer
manufacturing.
Pulp and Paper Manufacturing.. 322110 Pulp mills.
322120 Paper mills.
322130 Paperboard mills.
-----------------------------------------
Miscellaneous Uses of Facilities included elsewhere
Carbonate.
-----------------------------------------
Municipal Solid Waste 562212 Solid waste
Landfills. landfills.
221320 Sewage treatment
facilities.
Silicon Carbide Production.... 327910 Silicon carbide
abrasives
manufacturing.
Soda Ash Production........... 325180 Other basic inorganic
chemical
manufacturing: Soda
ash manufacturing.
Suppliers of Carbon Dioxide... 325120 Industrial gas
manufacturing
facilities.
Suppliers of Industrial 325120 Industrial greenhouse
Greenhouse Gases. gas manufacturing
facilities.
Titanium Dioxide Production... 325180 Other basic inorganic
chemical
manufacturing:
Titanium dioxide
manufacturing.
Underground Coal Mines........ 212115 Underground coal
mining.
Zinc Production............... 331410 Nonferrous metal
(except aluminum)
smelting and
refining: Zinc
refining, primary.
Importers and Exporters of Pre- 423730 Air-conditioning
charged Equipment and Closed- equipment (except
Cell Foams. room units) merchant
wholesalers.
333415 Air-conditioning
equipment (except
motor vehicle)
manufacturing.
423620 Air-conditioners,
room, merchant
wholesalers.
449210 Electronics and
Appliance retailers.
326150 Polyurethane foam
products
manufacturing.
335313 Circuit breakers,
power,
manufacturing.
423610 Circuit breakers and
related equipment
merchant
wholesalers.
------------------------------------------------------------------------

Table 1 of this preamble is not intended to be exhaustive, but
rather provides a guide for readers regarding facilities likely to be
affected by this proposed action. This table lists the types of
facilities that the EPA is now aware could potentially be affected by
this action. Other types of facilities than those listed in the table
could also be subject to reporting requirements. To determine whether
you would be affected by this proposed action, you should carefully
examine the applicability criteria found in 40 CFR part 98, subpart A
(General Provisions) and each source category. Many facilities that are
affected by 40 CFR part 98 have greenhouse gas emissions from multiple
source categories listed in Table 1 of this preamble. If you have
questions regarding the applicability of this action to a particular
facility, consult the person listed in the FOR FURTHER INFORMATION
CONTACT section.
Acronyms and Abbreviations. The following acronyms and
abbreviations are used in this document.

AGA American Gas Association
AIM American Innovation and Manufacturing Act of 2020
ANSI American National Standards Institute
API American Petroleum Institute
AR5 Fifth Assessment Report
AR6 Sixth Assessment Report
ASME American Society of Mechanical Engineers
ASTM American Society for Testing and Materials
BACT best available control technology
BAMM best available monitoring methods
BCFC bromochlorofluorocarbons
BFC bromofluorocarbons
BOPF basic oxygen process furnace
CAA Clean Air Act
CAS Chemical Abstract Service
CBI confidential business information
CBP U.S. Customs and Border Protection
CCUS carbon capture, utilization, and sequestration
CDC Centers for Disease Control and Prevention
CEMS continuous emission monitoring system
CFC chlorofluorocarbons
CFR Code of Federal Regulations
CGA cylinder gas audit
CF<INF>4</INF> perfluoromethane
CH<INF>4</INF> methane
CHP combined heat and power
CMA Conference of the Parties serving as the meeting of the Parties
to the Paris Agreement
CO<INF>2</INF> carbon dioxide
CO<INF>2</INF>e carbon dioxide equivalent
COVID-19 Coronavirus 2019
CSA CSA Group
DOC degradable organic carbon
DOE Department of Energy
DRE destruction and removal efficiency
EGU electricity generating unit
e-GGRT electronic Greenhouse Gas Reporting Tool
eGRID Emissions & Generation Resource Database
EF emission factor
EG emission guidelines
EIA Energy Information Administration
EOR enhanced oil recovery
EPA U.S. Environmental Protection Agency
ET Eastern time
FAQ frequently asked question
FR Federal Register
F-GHG fluorinated greenhouse gas
F-HTFs fluorinated heat transfer fluids
GHG greenhouse gas
GHGRP Greenhouse Gas Reporting Program
GWP global warming potential
HAWK HFC and ODS Allowance Tracking
HBCFC hydrobromochlorofluorocarbons
HBFC hydrobromofluorocarbons
HCFC hydrochlorofluorocarbons
HCFE hydrochlorofluoroethers
HFC hydrofluorocarbons
HFE hydrofluoroethers
HTF heat transfer fluid
HTS Harmonized Tariff System
ICR Information Collection Request
IPCC Intergovernmental Panel on Climate Change
ISBN International Standard Book Number
ISO International Standards Organization
IVT Inputs Verification Tool
k first order decay rate
kWh kilowatt hour
LDC local distribution company
MECS Manufacturing and Energy Consumption Survey
MEMP Metered Energy Monitoring Plan
mmBtu million British thermal units

[[Page 32855]]

MRV monitoring, reporting, and verification plan
mt metric tons
mtCO<INF>2</INF>e metric tons carbon dioxide equivalent
MWh megawatt-hour
MSW municipal solid waste
N<INF>2</INF>O nitrous oxide
NAICS North American Industry Classification System
NIST National Institute of Standards and Technology
NSPS new source performance standards
OMB Office of Management and Budget
PBI proprietary business information
PFC perfluorocarbon
POX partial oxidation
ppm parts per million
PRA Paperwork Reduction Act
PSA pressure swing adsorption
PSD prevention of significant deterioration
QA/QC quality assurance/quality control
RFA Regulatory Flexibility Act
REC renewable energy credit
RY reporting year
SAR Second Assessment Report
SDI Strategic Defense Initiative
SF6 sulfur hexafluoride
SMR steam methane reforming
TRL technology readiness level
TSD technical support document
UIC underground injection control
U.S. United States
UMRA Unfunded Mandates Reform Act of 1995
UNFCCC United Nations Framework Convention on Climate Change
WGS water gas shift
WWW World Wide Web

Contents

I. Background
A. How is this preamble organized?
B. Background on This Supplemental Proposed Rule
C. Legal Authority
II. Overview and Rationale for Proposed Amendments to 40 CFR Part 98
A. Revisions to Global Warming Potentials
B. Revisions To Expand Source Categories and Address Potential
Gaps in Reporting of Emissions Data for Specific Sectors
C. Improvements to Existing and Proposed Emissions Estimation
Methodologies
D. Revisions to Reporting Requirements To Improve Verification
and the Accuracy of the Data Collected
E. Technical Amendments, Clarifications, and Corrections
III. Proposed Amendments to Part 98
A. Subpart A--General Provisions
B. Subpart C--General Stationary Fuel Combustion Sources
C. Subpart F--Aluminum Production
D. Subpart G--Ammonia Manufacturing
E. Subpart I--Electronics Manufacturing
F. Subpart N--Glass Production
G. Subpart P--Hydrogen Production
H. Subpart Y--Petroleum Refineries
I. Subpart AA--Pulp and Paper Manufacturing
J. Subpart HH--Municipal Solid Waste Landfills
K. Subpart OO--Suppliers of Industrial Greenhouse Gases
L. Subpart PP--Suppliers of Carbon Dioxide
M. Subpart QQ--Importers and Exporters of Fluorinated Greenhouse
Gases Contained in Pre-Charged Equipment and Closed-Cell Foams
N. Subpart RR--Geologic Sequestration of Carbon Dioxide
O. Subpart UU--Injection of Carbon Dioxide
P. Subpart VV--Geologic Sequestration of Carbon Dioxide With
Enhanced Oil Recovery Using ISO 27916
IV. Proposed Amendments To Add New Source Categories to Part 98
A. Subpart B--Energy Consumption
B. Subpart WW--Coke Calciners
C. Subpart XX--Calcium Carbide Production
D. Subpart YY--Caprolactam, Glyoxal, and Glyoxylic Acid
Production
E. Subpart ZZ--Ceramics Production
V. Schedule for the Proposed Amendments
VI. Proposed Confidentiality Determinations for Certain Data
Reporting Elements
A. Overview and Background
B. Proposed Confidentiality Determinations
C. Proposed Reporting Determinations for Inputs to Emissions
Equations
D. Request for Comments on Proposed Category Assignments,
Confidentiality Determinations, or Reporting Determinations
VII. Impacts of the Proposed Amendments
VIII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act (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
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
K. Determination under CAA Section 307(d)

I. Background

A. How is this preamble organized?

Section I of this preamble contains background information on the
June 21, 2022 proposed rule (87 FR 36920, hereafter referred to as
``2022 Data Quality Improvements Proposal'') and how the EPA identified
additional information to support further revisions to improve the
GHGRP that are included in this supplemental proposal. This section
also discusses the EPA's legal authority under the Clean Air Act (CAA)
to promulgate (including subsequent amendments to) the GHG Reporting
Rule, codified at 40 CFR part 98 (hereinafter referred to as ``part
98''), and the EPA's legal authority to make confidentiality
determinations for new or revised data elements required by these
amendments or for existing data elements for which a confidentiality
determination has not previously been proposed. Section II of this
preamble describes the types of amendments included in this proposed
rule and includes the rationale for each type of proposed change.
Section III of this preamble is organized by existing part 98 subpart
and contains detailed information on the proposed revisions and the
rationale for the proposed amendments in each section. Section IV of
this preamble describes five newly proposed part 98 subparts and
contains detailed information and rationale for the requirements for
each proposed source category. Section V of this preamble discusses the
proposed schedule for implementing these revisions to part 98. Section
VI of this preamble discusses the proposed confidentiality
determinations for new or substantially revised (i.e., requiring
additional or different data to be reported) data reporting elements,
as well as for certain existing data elements for which the EPA is
proposing a new determination. Section VII of this preamble discusses
the impacts of the proposed amendments. Section VIII of this preamble
describes the statutory and Executive order requirements applicable to
this action.

B. Background on This Supplemental Proposed Rule

In the 2022 Data Quality Improvements Proposal, the EPA proposed
amendments to specific provisions of the GHGRP where we identified
opportunities for improvement, such as where the rule may be modified
to reflect the EPA's current understanding of U.S. GHG emission trends,
or to improve data collection and reporting where additional data may
be necessary to better understand emissions from specific sectors or
inform future policy decisions (87 FR 36920, June 21, 2022). The 2022
Data Quality Improvements Proposal included updates to emission factors
and refinements to existing emissions estimation methodologies to
reflect an improved understanding of emission sources and end uses of
GHGs. Additionally, it proposed to collect additional data to
understand new source categories or new emission sources for specific
sectors; to improve the EPA's understanding of the sector-

[[Page 32856]]

specific processes or other factors that influence GHG emission rates;
to improve verification of collected data; and to provide additional
data to complement or inform other EPA programs. In other cases, we
proposed revisions to resolve gaps in the current coverage of the GHGRP
that leave out potentially significant sources of GHG emissions or end
uses. For example, the proposed revisions included new reporting of
direct air capture as a carbon capture option for suppliers of carbon
dioxide; addition of a new subpart for quantifying geologic
sequestration in association with enhanced oil recovery operations; and
an updated calculation methodology to estimate emissions from large,
atypical release events at oil and gas facilities. The EPA also
proposed revisions that clarify or update provisions that may be
unclear, or where we identified specific provisions in part 98 that
would streamline calculation, monitoring, or reporting to provide
flexibility or increase the efficiency of data collection. Finally, the
EPA also solicited comment on expanding the GHGRP to include several
new source categories that could improve the EPA's understanding of
GHGs, including energy consumption; ceramics production; calcium
carbide production; caprolactam, glyoxal, and glyoxylic acid
production; coke calcining; and CO<INF>2</INF> utilization (see section
IV of the 2022 Data Quality Improvements Proposal at 87 FR 37016), as
well as requesting comment on potential future amendments to add new
calculation, monitoring, and reporting requirements.
As stated in the 2022 Data Quality Improvements Proposal, the data
collected under part 98 are used to inform the EPA's understanding of
the relative emissions and distribution of emissions from specific
industries, the factors that influence GHG emission rates, and to
inform policy options and potential regulations. Since publishing the
proposed amendments, the EPA has received or identified new information
to further improve the data collected under the GHGRP, and has
subsequently identified additional amendments that the EPA is putting
forward in this supplemental proposal. Some of the additional
amendments are informed by a review of comments raised by stakeholders
on the 2022 Data Quality Improvements Proposal (e.g., see sections
III.J and III.P of this preamble). Other proposed changes are based on
additional data gaps the EPA has observed in collected data, either
where additional data would improve verification of data reported to
the GHGRP (see section II.D of this preamble) or where additional data
is needed to help our understanding of changing industry emission
trends (see sections II.B and II.C of this preamble). Based on review
of this information, the EPA is proposing additional amendments to part
98, described in sections II through IV of this preamble, that build on
and improve the amendments proposed in the 2022 Data Quality
Improvements Proposal or that would further enhance the quality of part
98 and implementation of the GHGRP.
In some cases, the EPA has identified updated guidance on GHG
estimation methods or advances in the scientific literature. For
example, through this notification, the EPA is proposing a
comprehensive update to the global warming potentials (GWPs) in Table
A-1 to subpart A of part 98, in part to ensure that the GWPs used in
the GHGRP are consistent with those recently agreed upon by the Parties
to the United Nations Framework Convention on Climate Change (UNFCCC)
for purposes of GHG reporting. The Parties specified the agreed-on GWPs
in November 2021 (see section III.A.1 of this preamble), which was too
late to allow the EPA to consider proposing a comprehensive GWP update
in the 2022 Data Quality Improvement Proposal.\1\ We have subsequently
reviewed and are proposing to include updated GWPs in this proposed
rule.
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\1\ Although we proposed changes to certain chemical specific
and default global warming potentials in Table A-1 to subpart A of
part 98 in the 2022 Data Quality Improvements Proposal, these were
limited updates to GWPs of fluorinated GHGs that are not required to
be reported under the UNFCCC because they are not
hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, or
nitrogen trifluoride.
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In other cases, we have identified new data supporting additional
improvements to the calculation, monitoring, and recordkeeping
requirements, including revisions and clarifications not previously
proposed, that would address potential data gaps and improve the
quality of the data collected in the GHGRP. For example, the EPA is
proposing to incorporate additional revisions to the Municipal Solid
Waste (MSW) landfill source category in light of recent aerial studies
that indicate that methane emissions from landfills may be considerably
higher than the methane emissions currently reported under subpart HH
of part 98 (Municipal Solid Waste Landfills). The proposed amendments
incorporate an updated emissions estimation methodology that would
improve the accuracy and coverage of the greenhouse gas data from
landfills. These data would be used to inform the EPA's understanding
of methane emissions from MSW landfills and future policy decisions
under the CAA. For example, the current equations account for fugitive
methane emissions passing through intact cover systems. Collecting
surface emissions data under the proposed revisions would inform the
EPA's understanding of the degree to which breakdown in cover materials
is occurring and the impacts on methane emission rates.
This supplemental proposal also incorporates consideration of
information received in response to our request for comment on certain
topics in the 2022 Data Quality Improvement Proposal. In that proposal,
we requested comment on potential future amendments to improve the
coverage of U.S. GHG emissions and supply captured by the GHGRP. The
EPA has reviewed comments received in response to the call for
information, along with additional data that the EPA has collected, and
is proposing to establish new subparts with specific reporting
provisions under part 98 for the source categories of energy
consumption; coke calciners; ceramics production; calcium carbide
production; and caprolactam, glyoxal, and glyoxylic acid production.
The proposed revisions would improve the data collected under the GHGRP
by better capturing the changing landscape of greenhouse gas emissions,
providing for more complete coverage of U.S. GHG emission sources, and
providing a more comprehensive approach to understanding GHG emissions.
For other revisions, we are proposing to clarify or correct
specific proposed provisions of the 2022 Data Quality Improvements
Proposal. For instance, we are proposing to clarify the applicability
requirements of proposed subpart VV of part 98 (Geologic Sequestration
of Carbon Dioxide With Enhanced Oil Recovery Using ISO 27916), a new
subpart for quantifying geologic sequestration in association with
enhanced oil recovery (EOR) operations, which was included in the 2022
Data Quality Improvements Proposal. Following the initial proposal, we
received feedback from stakeholders highlighting ambiguity in the
applicability of the proposed source category and questioning whether
EOR operators electing to use the International Standards Organization
(ISO) standard designated as CSA Group (CSA)/American National
Standards Institute (ANSI) ISO 27916:2019, Carbon Dioxide Capture,
Transportation

[[Page 32857]]

and Geological Storage--Carbon Dioxide Storage Using Enhanced Oil
Recovery (CO2-EOR) (hereafter referred to as ``CSA/ANSI ISO
27916:2019''), must mandatorily report under the new proposed subpart
VV or would have the option to continue reporting under subpart UU
(Injection of Carbon Dioxide). We are proposing the applicability of
the source category in this supplemental notification to better reflect
our initial intent, which was that operators electing to use CSA/ANSI
ISO 27916:2019 to quantify geologic sequestration of CO<INF>2</INF>
would be required to report under subpart VV, and proposing harmonizing
revisions to subpart UU (Injection of Carbon Dioxide). This
supplemental proposal provides information about these proposed updates
for public review and comment.
This supplemental proposal does not address implementation of
provisions of the Inflation Reduction Act which was signed into law on
August 16, 2022. Section 60113 of the Inflation Reduction Act amended
the CAA by adding section 136, ``Methane Emissions and Waste Reduction
Incentive Program for Petroleum and Natural Gas Systems.'' The EPA
intends to take one or more separate actions in the coming months
related to implementation of the Methane Emissions and Waste Reduction
Incentive Program, including a future rulemaking to propose revisions
to certain requirements of subpart W of part 98 (Petroleum and Natural
Gas Systems). Accordingly, the Methane Emissions and Waste Reduction
Incentive Program is outside the scope of this supplemental proposed
rule.

C. Legal Authority

The EPA is proposing these rule amendments under its existing CAA
authority provided in CAA section 114. As stated in the preamble to the
Mandatory Reporting of Greenhouse Gases final rule (74 FR 56260,
October 30, 2009) (hereinafter referred to as ``2009 Final Rule''), CAA
section 114(a)(1) provides the EPA broad authority to require the
information proposed to be gathered by this rule because such data
would inform and are relevant to the EPA's carrying out of a variety of
CAA provisions. See the preambles to the proposed GHG Reporting Rule
(74 FR 16448, April 10, 2009) (hereinafter referred to as ``2009
Proposed Rule'') and the 2009 Final Rule for further information.

II. Overview and Rationale for Proposed Amendments to 40 CFR Part 98

In general, this supplemental proposal includes the following
proposed revisions to better inform EPA policies and programs under the
CAA:
<bullet> Revisions to Table A-1 to the General Provisions of part
98 to include updated GWPs to reflect advances in scientific knowledge
and better characterize the climate impacts of certain GHGs, including
agreed-upon values established by the UNFCCC, and to maintain
comparability and consistency with the Inventory of U.S. Greenhouse Gas
Emissions and Sinks \2\ (hereafter referred to as ``the Inventory'')
and other analyses produced by the EPA;
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\2\ The EPA's GHG Inventory is available at <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>.
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<bullet> Revisions to expand source categories or add new source
categories to address potential gaps in reporting of emissions data for
specific sectors in order to improve the accuracy and completeness of
the data provided by the GHGRP;
<bullet> Revisions to refine existing calculation methodologies to
reflect an improved understanding of emissions sources and end uses of
GHGs, to incorporate more recent research on GHG emissions or
formation, or to improve verification of reported emissions;
<bullet> Revisions to add or modify reporting requirements to
eliminate data gaps and improve verification of emissions estimates;
and
<bullet> Revisions that clarify requirements that reporters have
previously found vague to ensure that accurate data are being
collected, and editorial corrections or harmonizing changes that would
improve the public's understanding of the rule.
Overall, the proposed changes in this supplemental notification
would provide a more comprehensive, nationwide GHG emissions profile
reflective of the origin and distribution of GHG emissions in the
United States and would more accurately inform EPA policy options for
potential regulatory or non-regulatory CAA programs. The EPA
additionally uses the data from the GHGRP, which would include data
from these proposed changes, to improve estimates used in the
Inventory.
Sections II.A through II.E of this preamble provide additional
rationale for the proposed changes. Details for the specific amendments
proposed for each subpart are included in sections III and IV of this
preamble. We are seeking public comment only on the proposed revisions
and issues specifically identified in this supplemental notification
for the identified subparts. We expect to deem any comments received in
response to this notification that address other aspects of 40 CFR part
98 to be outside of the scope of this supplemental proposed rulemaking.

A. Revisions to Global Warming Potentials

Table A-1 to subpart A of 40 CFR part 98 (``Table A-1'') is a
compendium of chemical-specific and default GWP values of GHGs that are
required to be reported under one or more subparts of the GHG Reporting
Rule. These GWPs are used to convert tons of chemical into tons of
CO<INF>2</INF>-equivalent (CO<INF>2</INF>e) for purposes of various
calculations and reporting under the rule. The EPA is proposing
revisions to Table A-1 to update the chemical-specific GWP values of
certain GHGs to reflect GWPs from the IPCC Fifth Assessment Report
(hereinafter referred to as ``AR5'') \3\ and, for certain GHGs that do
not have chemical-specific GWPs listed in AR5, to adopt GWP values from
the IPCC Sixth Assessment Report (hereinafter referred to as
``AR6'').\4\ The EPA is also proposing to revise and expand the set of
default GWPs in Table A-1, which are applied to GHGs for which peer-
reviewed chemical-specific GWPs are not available. With these changes,
the GWP values in Table A-1 would reflect more recent science regarding
the atmospheric impacts of non-CO<INF>2</INF> GHGs, and the GWP values
used for the GHGRP would continue to be consistent with the GWP values
used for the Inventory and other EPA programs. (As

[[Page 32858]]

discussed further below, the Inventory incorporates the GWP values
agreed on by the parties to the UNFCCC, who agreed to use the GWP
values in AR5 beginning in 2024.)
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\3\ IPCC, 2013: Climate Change 2013: The Physical Science Basis.
Contribution of Working Group I to the Fifth Assessment Report of
the Intergovernmental Panel on Climate Change [Stocker, T.F., D.
Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels,
Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press,
Cambridge, United Kingdom and New York, NY, USA, 1535 pp. The GWPs
are listed in Table 8.A.1 of Appendix 8.A: Lifetimes, Radiative
Efficiencies and Metric Values, which appears on pp. 731-737 of
Chapter 8, ``Anthropogenic and Natural Radiative Forcing.''
\4\ Smith, C., Z.R.J. Nicholls, K. Armour, W. Collins, P.
Forster, M. Meinshausen, M.D. Palmer, and M. Watanabe, 2021: The
Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity
Supplementary Material. 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.)]. Available from
www.ipcc.ch/ The AR6 GWPs are listed in Table 7.SM.7, which appears
on page 16 of the Supplementary Material.
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As discussed in this section of the preamble, the GWP values
currently in Table A-1 to part 98 are drawn both from the IPCC Fourth
Assessment Report \5\ (hereinafter referred to as ``AR4'') and, for
multiple GHGs that do not have GWPs listed in AR4, from AR5. The
proposed GWP values are drawn from AR5, and for multiple GHGs that do
not have GWPs listed in AR5, from AR6. Consistent with our approach
since the inception of the GHGRP, we are proposing to adopt the AR5 and
AR6 GWPs based on a 100-year time horizon. Note that these proposed
revisions are in addition to the 2022 Data Quality Improvements
Proposal to add a chemical-specific GWP of 0.14 for carbonic difluoride
and to expand the fluorinated greenhouse gas (F-GHG) group for several
types of unsaturated compounds to include additional types of
unsaturated compounds. GWPs that have been newly evaluated or
reevaluated in the peer-reviewed scientific literature are periodically
consolidated and published by the IPCC. Since 1990, there have been six
IPCC Assessment Reports, each of which included a set of revised and
expanded GWPs. For purposes of reporting their GHG emissions under the
UNFCCC, the Parties to the UNFCCC have successively adopted the 100-
year GWPs in three of the IPCC Assessment Reports, beginning with the
SAR, advancing to AR4 and, starting in 2024, moving to AR5.
---------------------------------------------------------------------------

\5\ IPCC Fourth Assessment Report (AR4), 2007. Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to
the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A.
(eds.)]. IPCC, Geneva, Switzerland, 104 pp.
---------------------------------------------------------------------------

Published in 2014, AR5 includes revised GWPs for the GHGs with GWPs
in AR4 as well as for multiple additional GHGs. The revised GWPs
reflect advances in scientific knowledge on the radiative efficiencies,
atmospheric lifetimes, and other characteristics of these GHGs and of
CO<INF>2</INF>, and they also account for the growing background
concentrations of GHGs (particularly CO<INF>2</INF>) in the
atmosphere.\6\ AR5 therefore reflects an improved scientific
understanding of the radiative effects \7\ of these gases in the
atmosphere. As noted in the preamble to the 2009 Final Rule, it is the
EPA's intent to periodically update Table A-1 through notice and
comment rulemaking as GWPs are evaluated or re-evaluated by the
scientific community (74 FR 56348; October 30, 2009). Further, as noted
in the preamble to the 2013 Revisions to the Greenhouse Gas Reporting
Rule and Final Confidentiality Determinations for New or Substantially
Revised Data Elements (78 FR 71904, 71911; November 29, 2013, hereafter
``the 2013 Final Rule''), which updated GWPs in Table A-1, ``each
successive assessment provides more accurate GWP estimates as
experiments and improved computational methods lead to more accurate
estimates of the radiative efficiencies, atmospheric lifetimes, and
indirect effects of the various gases. Additionally, the more recent
assessments reflect more up-to-date background concentrations, which
are necessary for accurately calculating the radiative efficiency of
the different gases.'' Therefore, adopting the GWP values in AR5 (and
in AR6 for GHGs that do not have GWPs in AR5) would support the overall
goals of the GHGRP to collect high-quality GHG data and to incorporate
metrics that reflect scientific updates as they are adopted.
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\6\ Increasing background concentrations of a GHG in the
atmosphere can lower the impact of subsequent emissions.
\7\ Radiative forcing is the measurement of the capacity of a
gas or other forcing agent to affect the balance of energy in
Earth's atmosphere based in the difference in incoming solar
radiation and outgoing infrared radiation.
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The proposed changes to Table A-1 would also ensure that the data
collected in the GHGRP can be compared to the data collected and
presented by other EPA programs and by national and international GHG
inventories. The proposed changes, with a proposed effective date of
January 1, 2025 (therefore applicable to data submitted for calendar
year/reporting year 2024, i.e., RY2024),\8\ would maintain long-term
consistency between the GHGRP GWPs and the GWPs used for the Inventory,
which are scheduled to change from the AR4 GWPs to the AR5 GWPs for the
1990-2022 Inventory.\9\
---------------------------------------------------------------------------

\8\ As discussed in section III.A.2 of the preamble, current 40
CFR 98.3(k) provides that facilities or suppliers that first become
subject to any subpart of part 98 solely due to an amendment to
Table A-1 are not required to submit an annual GHG report (or, for
facilities or suppliers that already report under the GHGRP, a
report for the subpart to which they are newly subject) for the
reporting year during which the change in GWPs is published.
However, they are required to begin monitoring their emissions and
supplies for the subpart(s) to which they are newly subject
beginning on January 1 of the year following publication of the
amendment to Table A-1.
\9\ Due to the time required to complete this proposed rule to
adopt the AR5 GWPs, if this proposed rule is finalized, emissions
from at least two years, 2022 and 2023, would be weighted by
different sets of GWPs under part 98 and the Inventory.
---------------------------------------------------------------------------

The Inventory is a comprehensive assessment of U.S. GHG emissions
based on national-level data and follows the reporting guidelines set
by the UNFCCC.\10\ The United States is a party to the UNFCCC and
submits the Inventory to the Secretariat of the UNFCCC as part of
annual obligations under the treaty. To ensure consistency and
comparability with national inventory data submitted by other UNFCCC
Parties, the Inventory submitted to the UNFCCC uses internationally
accepted methods and common reporting metrics agreed upon by the
Parties (including the United States) to develop and characterize
emission estimates.
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\10\ See Articles 4 and 12 of the Convention on Climate Change.
Parties to the Convention, by ratifying, ``shall develop,
periodically update, publish and make available * * * national
inventories of anthropogenic emissions by sources and removals by
sinks of all greenhouse gases not controlled by the Montreal
Protocol, using comparable methodologies * * *.'' See <a href="https://unfccc.int/resource/docs/convkp/conveng.pdf">https://unfccc.int/resource/docs/convkp/conveng.pdf</a>.
---------------------------------------------------------------------------

As described in the preamble of the 2009 Proposed Rule, the GHGRP
is intended to gather information that is relevant to the EPA's
carrying out a wide variety of CAA provisions, with the goal of
supplementing and complementing existing U.S. Government programs
related to climate policy and research, including the Inventory
submitted to the UNFCCC. The GHGRP provides data that can inform
analysis of potential U.S. climate policies and programs, which is also
one of the uses for the data developed for the Inventory. The GHGRP
complements the Inventory and other U.S. programs by providing data
from certain individual facilities and suppliers, generally those above
certain thresholds. Collected facility, unit, and process-level GHG
data from the GHGRP are also used to develop and confirm the national
statistics and emission estimates presented in the Inventory, which are
calculated using aggregated national data.
Throughout the development and implementation of the GHG Reporting
Rule, the EPA has proposed and finalized calculation methodologies and
reporting metrics that were consistent with the international reporting
standards under the UNFCCC. This approach has allowed the data
collected under the GHGRP to be easily compared to the data in the
Inventory and to data from other national and international programs,
facilitating the analysis of potential U.S. climate policies and
programs. Specifically, in the 2009 Final Rule, the EPA generally
promulgated

[[Page 32859]]

GWP values published in the IPCC Second Assessment Report \11\
(hereafter referred to as ``SAR GWP values'') to convert mass emissions
(or supplies) of each GHG into a common unit of measure,
CO<INF>2</INF>e, for final reporting. Although the IPCC published AR4
prior to publication of the 2009 Final Rule, the UNFCCC continued to
require the use of SAR GWP values for reporting in the Inventory at the
time the rule was promulgated, and up until 2014.\12\ In the 2013 Final
Rule, the EPA revised the GHGRP's GWP values, after consideration of a
UNFCCC decision reached by UNFCCC member parties and published on March
15, 2012, to require countries submitting an annual inventory report in
2015 and beyond to use AR4 GWP values.\13\ The 2013 Final Rule adopted
the IPCC AR4 GWP values in Table A-1, in part in order to maintain
comparability and consistency with the updated international reporting
standards under the UNFCCC and the revised requirements for official
emission estimates to be reported by the United States and other
parties. Following the 2013 Final Rule, the EPA published a separate
rule to add GWPs to Table A-1 for a number of F-GHGs and fluorinated
heat transfer fluids (F-HTFs) for which GWPs were not provided in AR4
or previous scientific assessments (79 FR 73750, December 11, 2014,
hereinafter referred to as the ``2014 Fluorinated GHG Final
Rule'').\14\ The 2014 Fluorinated GHG Final Rule included chemical-
specific GWPs primarily drawn from AR5, as well as default GWPs
intended for F-GHGs and F-HTFs for which peer-reviewed GWPs were not
available in AR4, AR5, or other sources. The default GWPs were
calculated and applied to 12 fluorinated GHG groups composed of
compounds with similar chemical structures, atmospheric lifetimes, and
GWPs, and were based on the average GWPs of the chemically similar
fluorinated GHGs for which a chemical-specific GWP was available in
Table A-1 or AR5. As such, the changes from the 2014 Fluorinated GHG
Final Rule reflected the latest scientific consensus regarding F-GHGs
that did not have GWPs in earlier assessments and expanded the number
of compounds reflected in Table A-1, resulting in more accurate and
complete estimates of GHG emissions. At the same time, the 2014
Fluorinated GHG Final Rule maintained consistency between the GHGRP and
the Inventory by retaining the AR4 GWP values where those were
available.
---------------------------------------------------------------------------

\11\ IPCC Second Assessment Report (SAR), 1995. Climate Change
1995: The Science of Climate Change, Contribution of Working Group I
to the Second Assessment Report of the Intergovernmental Panel on
Climate Change [Houghton, J.T.; Meira Filho, L.G.; Callander, B.A.;
Harris, N.; Kattenberg, A.; Maskell, K. (eds.)., Cambridge
University Press, Cambridge, United Kingdom, 572 pp.
\12\ As discussed further in this section of this preamble, the
EPA did adopt AR4 values in 2009 for GHGs that did not have SAR GWP
values because doing so increased the accuracy and completeness of
the GWP-weighted emissions calculated and reported under the GHGRP
without introducing any inconsistency with UNFCCC reporting.
\13\ Refer to <a href="https://unfccc.int/">https://unfccc.int/</a>. See Decision 15/CP.17,
Revision of the UNFCCC reporting guidelines on annual inventories
for Parties included in Annex I to the Convention.
\14\ As noted in the 2014 Fluorinated GHG Final Rule, the
addition of GWPs for compounds that did not have GWPs in AR4 was
consistent with the UNFCCC Reporting Guidelines, which ``strongly
encourage'' Annex I Parties ``to also report emissions and removals
of additional GHGs'' (i.e., GHGs whose GWPs are not included in
AR4).
---------------------------------------------------------------------------

In the 2013 Final Rule, we noted ``the EPA may consider adoption of
AR5 GWPs or other GWP values for compounds currently listed in Table A-
1 (i.e., compounds for which AR4 GWPs are currently listed in Table A-
1) if these values are adopted by the UNFCCC and the global community''
(78 FR 71912; November 29, 2013).
In December 2018, the Parties to the UNFCCC agreed to require use
of the 100-year time-horizon GWP values from AR5 in annual inventory
reports submitted in 2024 and future years.\15\ In November 2021, the
parties clarified which of the two sets of GWPs in AR5 were to be used:
those in Table 8.A.1.\16\ Accordingly, the United States has an annual
commitment to submit the Inventory for 2024 and subsequent years using
the revised AR5 GWP values in Table 8.A.1. The Inventory for 2024 will
contain national-level estimates of emissions for each year from 1990-
2022. In order to ensure that the GHGRP continues to rely on recent
scientific data and uses methods consistent with UNFCCC guidelines, as
the EPA intended in the development of the 2009 Final Rule and in
revisions to the GHGRP since then, we are proposing to revise the GWP
values in Table A-1 of part 98 to reflect updated AR5 GWP values, which
would apply to annual reports beginning with RY2024. The proposed
changes would continue to keep the reporting metrics in part 98
consistent with the updated international reporting standards followed
by the Inventory and allow the GHGRP to continue to provide the
additional benefit of complementing and informing the Inventory
submitted to the UNFCCC.\17\
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\15\ Refer to <a href="https://unfccc.int/">https://unfccc.int/</a>. See Annex to Decision 18/
CMA.1, paragraph 37. ``Each Party shall use the 100-year time-
horizon global warming potential (GWP) values from the IPCC Fifth
Assessment Report, or 100-year time-horizon GWP values from a
subsequent IPCC assessment report as agreed upon by the [Conference
of the Parties serving as the meeting of the Parties to the Paris
Agreement] (CMA), to report aggregate emissions and removals of
GHGs, expressed in CO2 eq.''
\16\ Decision 5/CMA.3, paragraph 25 reads ``the 100-year time-
horizon global warming potential values referred to in decision 18/
CMA.1, annex, paragraph 37, shall be those listed in Table 8.A.1 of
the Fifth Assessment Report of the Intergovernmental Panel on
Climate Change, excluding the value for fossil methane.'' See
<a href="https://unfccc.int/sites/default/files/resource/CMA2021_L10a2E.pdf">https://unfccc.int/sites/default/files/resource/CMA2021_L10a2E.pdf</a>.
\17\ The updates to Table A-1 would not affect the GWP-weighted,
CO<INF>2</INF>-equivalent totals certified by facilities or
suppliers in their annual reports for reporting years before RY2023.
However, to ensure that GWP-weighted totals are used in analyses and
displayed to the public in a consistent manner from RY2010/2011
through RY2023 and later years, the updated GWPs would be applied to
the entire time series in analyses and in EPA's Facility Level
Information on GreenHouse gases Tool (FLIGHT) at <a href="https://ghgdata.epa.gov/ghgp/main.do">https://ghgdata.epa.gov/ghgp/main.do</a>. This approach is consistent with the
approach taken for previous updates of Table A-1. See, e.g., 78 FR
71937.
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For GHGs that do not have GWPs in AR5 but do have GWPs in AR6, we
are proposing to adopt the AR6 GWPs. Currently, default GWPs are
applied to these compounds based on the fluorinated GHG group to which
they belong. While the default GWPs are, on average, expected to be
reasonably accurate across the fluorinated GHGs within a fluorinated
GHG group, the AR6 GWP for an individual compound is expected to be
more accurate for that compound than the corresponding default GWP.
This is because the AR6 GWP takes into consideration the radiative
efficiency and atmospheric lifetime of the individual compound. Thus,
adopting the AR6 GWPs for GHGs that do not have GWPs in AR5 is expected
to improve the accuracy with which the atmospheric impacts of the gases
are reflected in annual reports, threshold determinations, and other
calculations. The specific changes that we are proposing to Table A-1
and the rationale for the GWPs proposed to be adopted are described
further in section III.A.1 of this preamble.
We recognize that some other EPA programs use the GWP values in
Table A-1 to determine the applicability of their individual program
requirements to direct emitters or suppliers above certain thresholds.
Issues related to other EPA programs that use the GHGRP GWP values in
Table A-1 are outside the scope of this proposed rule. To the extent
that a Table A-1 amendment raises such questions or concerns, please
work with the respective EPA office for that other EPA program. We also
recognize that non-EPA programs use the GWP values in Table A-1 to part
98. Issues related to non-EPA programs that use the GHGRP GWP values in

[[Page 32860]]

Table A-1 are also outside the scope of this proposed rule. As
explained in this section above, this rulemaking proposes to update
GWPs for the GHGRP consistent with recent science and the intent the
EPA expressed at the time the GHGRP was first promulgated. Thus, under
this supplemental proposal, we are seeking comments on the specific GWP
values proposed in this action for the GHGRP.

B. Revisions To Expand Source Categories and Address Potential Gaps in
Reporting of Emissions Data for Specific Sectors

In the 2022 Data Quality Improvements Proposal, the Agency stated
that it was considering future revisions to the GHG Reporting Rule to
potentially expand existing source categories or develop new source
categories that would add calculation, monitoring, reporting, and
recordkeeping requirements for certain sectors of the economy.
Specifically, the 2022 Data Quality Improvements Proposal solicited
comment on the potential addition of GHG reporting requirements related
to energy consumption; CO<INF>2</INF> utilization; ceramics production;
calcium carbide production; caprolactam, glyoxal, and glyoxylic acid
production; and coke calcining. The EPA solicited comment on these six
source categories where we identified that additional data from these
emission sources would help eliminate data gaps, improve the coverage
of the GHGRP, and better inform future EPA policy and programs under
the CAA. We identified cases where certain emission sources may
potentially contribute significant GHG emissions that are not currently
reported, or where facilities representative of these source categories
may currently report under another part 98 source category using
methodologies that may not provide complete or accurate emissions. We
also identified where the inclusion of potential source categories
would improve the completeness of the emissions estimates presented in
the Inventory, such as collection of data on ceramics production,
calcium carbide production, and caprolactam, glyoxal, and glyoxylic
acid production. The 2022 Data Quality Improvements Proposal also
included similar amendments to add reporting of new emissions or
emissions sources for certain existing sectors to address potential
gaps in reporting, e.g., where we proposed to add requirements for the
monitoring, calculation, and reporting of F-GHGs other than
SF<INF>6</INF> and perfluorocarbons (PFCs) under subpart DD (Electrical
Equipment and Distribution Equipment Use) to account for the
introduction of alternative technologies and replacements for
SF<INF>6</INF>, including fluorinated gas mixtures such as
fluoronitriles or fluoroketones mixed with carrier gases, as a
replacement for dielectric insulation gases (87 FR 37000; June 21,
2022).
Following the June 21, 2022 request for comment, the EPA has
reviewed information provided from stakeholders and considered
additional data to further support the development of reporting
requirements for five source categories. After that consideration, we
are proposing to add annual reporting requirements for greenhouse gases
from the following sources categories in new subparts to part 98 as
follows: subpart B (Energy Consumption); subpart WW (Coke Calciners);
subpart XX (Calcium Carbide Production); subpart YY (Caprolactam,
Glyoxal, and Glyoxylic Acid Production); and subpart ZZ (Ceramics
Production). As explained in the 2022 Data Quality Improvements
Proposal, the collection of such data would continue to inform, and are
relevant to, the EPA's carrying out a wide variety of CAA provisions.
Additional information on the data and rationale informing the proposed
definition of the source category, reporting thresholds, calculation,
monitoring, quality assurance, missing data, verification, and data
reporting and recordkeeping requirements for these five proposed new
source categories are included in section IV of this preamble.
The EPA is also proposing amendments that would expand the coverage
of the GHGRP for one subpart not included in the 2022 Data Quality
Improvements Proposal. Since the publication of the proposed rule, we
have identified a gap in coverage for certain emission sources, where
revisions to existing applicability and reporting requirements would
help the EPA to better understand and track emissions in specific
sectors and better inform future EPA policy and programs under the CAA.
In this supplemental proposal, we are proposing to amend the
applicability of subpart P (Hydrogen Production) to expand reporting to
include all hydrogen plants. The current source category definition in
subpart P is limited to merchant hydrogen production facilities,
including facilities that sell hydrogen and that may be located within
another facility if they are not owned by, or under the direct control
of, the other facility's owner and operator. The current definition
inadvertently excludes non-merchant hydrogen production facilities
(i.e., facilities that do not sell hydrogen or captive hydrogen
plants). Although some non-merchant hydrogen production facilities may
report under subpart Y (Petroleum Refineries), the EPA has identified
that there may be other non-merchant or captive hydrogen plants whose
emissions are not currently captured by part 98. The proposed
amendments would address this gap in reporting and allow the EPA to
better understand and track emissions from these facilities, which
would better inform future EPA policy and programs under the CAA.
Section III.G of this preamble provides additional information on the
proposed amendments.
Additionally, we are proposing to amend subpart HH (Municipal Solid
Waste Landfills) to expand reporting to account for methane emissions
from large releases that are currently not quantified under the GHGRP.
Specifically, we are proposing to revise calculation methodologies in
subpart HH to account for cover system leaks to better account for
large release events. The EPA has identified recent studies indicating
that methane emissions from landfills may be considerably higher than
what is currently reported to part 98 due to emissions from poorly
operating gas collection systems or destruction devices and cover
system leaks. We are proposing to revise the monitoring and calculation
methodologies in subpart HH to account for these scenarios.
Specifically, we note that owners or operators of landfills with gas
collection systems subject to the control requirements in the new
source performance standards (NSPS) as implemented in 40 CFR part 60,
subparts WWW or XXX, emission guidelines (EG) as implemented in 40 CFR
part 60, subparts Cc or Cf, or the Federal plan as implemented in 40
CFR part 62, subparts GGG and OOO are required to conduct surface
methane concentration measurements to ensure proper operation of the
gas collection system. We are proposing that subpart HH reporters with
landfills for which surface methane concentration measurements are
conducted under the NSPS, EG, or Federal plan would estimate emissions
for cover leaks based on a count of the number of exceedances
identified during the surface measurement period and the proposed
revised equations HH-6, HH-7, and HH-8 to adjust reported methane
emissions to account for these exceedances. Subpart HH reporters with
landfills with gas collection systems that are not required to conduct
surface methane concentration measurements under the NSPS, EG, or
Federal plan may elect to conduct these

[[Page 32861]]

measurements according to the method provided in the proposal and
adjust the emissions based on the number of exceedances identified. If
such subpart HH reporters do not elect to conduct such measurements,
the EPA is proposing that reporters with these landfills would use a
surface methane collection efficiency that is 10 percent lower than for
landfills with gas collection systems that are conducting surface
methane concentration measurements. These proposed amendments would
address a potentially large subset of emissions that are currently
omitted in reporting and improve the EPA's understanding of emissions
from these facilities. The improved data would subsequently better
inform Agency policies and programs under the CAA.

C. Improvements to Existing Emissions Estimation Methodologies

The EPA is proposing several additional revisions to modify
calculation equations to incorporate refinements to methodologies based
on an improved understanding of emission sources. In the 2022 Data
Quality Improvements Proposal, we identified amendments to emission
estimation methodologies where there are discrepancies between
assumptions in the current emission estimation methods and the
processes or activities conducted at specific facilities, or where we
identified more recent studies on GHG emissions or formation that
reflect updates to scientific understanding of GHG emissions sources.
We proposed changes that are intended to improve the quality and
accuracy of the data collected under the GHGRP, increase our
understanding of the relative distribution of GHGs that are emitted,
and better reflect GHG end uses or where GHGs are bound in products.
Since the development of the 2022 Data Quality Improvements
Proposal, we have identified several calculation provisions of part 98
that would benefit from amendments that update, clarify, or improve the
calculation methodology. For example, we are proposing to revise
calculation methodologies in subpart HH (Municipal Solid Waste
Landfills) to more clearly delineate the calculations needed when there
are multiple landfill gas recovery systems in place. During
verification of subpart HH reports, we identified issues in how the
electronic Greenhouse Gas Reporting Tool (e-GGRT) system calculates
emissions when multiple control devices are associated with a single
measurement location and when multiple measurement locations may be
used for a single recovery system. If a single recovery system is used,
but an additional measurement location is added to the system in mid-
year, the ``f<INF>Rec,c</INF>'' term associated with the new
measurement location (currently, the fraction of annual operating hours
the associated recovery system was operating) is calculated as 0.5 and
assumes the recovery system operated only half the year. The current
equations (equations HH-7 and HH-8) are set up with the assumption that
each measurement location is associated with a single recovery system,
however this is not always the case. We also found errors in
determining the ``f<INF>Dest</INF>'' term (fraction of annual hours the
destruction device was operating) in equations HH-6 and HH-8 when
multiple destruction devices are used for a single measurement
location. If, for example, a measurement location operates continuously
(8,760 hours per year), with flow from the measurement location
directed to an engine (approximately 8,400 hours per year), diverted to
a flare when the engine is down for maintenance (approximately 360
hours per year), and if the control devices were operating at all times
gas was directed to the device, the f<INF>Dest</INF> term should be 1
for each device. However, the f<INF>Dest</INF> term is often calculated
as the average of 0.959 (8400/8760) and 0.041 (360/8760), resulting in
a value of 0.5. Therefore, we are proposing revisions to equations HH-
6, HH-7, and HH-8 to more clearly define these terms, as well as to
adjust the equations to be able to account for landfills with multiple
gas collection systems or for a single gas collection system with
multiple measurement locations. These proposed revisions would improve
the quality and accuracy of the data collected under subpart HH.
We are proposing to clarify the calculation methodology for
reporters whose hydrogen unit routes process emissions to a stack with
CEMS, but fuel combustion emissions from the unit are routed to a
different stack which is not monitored with a CEMS. The proposed rule
would require reporters to calculate the CO<INF>2</INF> emissions from
fuel combustion from the hydrogen process unit using the mass balance
equations in subpart P (Hydrogen Production) considering only fuel
inputs and report the sum of these emissions plus the process
CO<INF>2</INF> emissions measured by the CEMS. The proposed amendments
would clarify the reporting requirements for cases where hydrogen
production process and combustion emissions are emitted through
separate stacks and the process emissions are measured with a CEMS, but
the combustion emissions are not.
We are also proposing to revise subpart AA (Pulp and Paper
Manufacturing) to add a calculation methodology for biogenic
CO<INF>2</INF> emissions from the combustion of biomass other than
spent liquor solids. The rule currently only includes methodologies to
calculate CO<INF>2</INF>, CH<INF>4</INF>, and N<INF>2</INF>O emissions
from the combustion of fossil fuels, and CH<INF>4</INF>,
N<INF>2</INF>O, and biogenic CO<INF>2</INF> emissions from the
combustion of spent liquor solids. Therefore, we are proposing to add
methodologies to calculate CH<INF>4</INF>, N<INF>2</INF>O, and biogenic
CO<INF>2</INF> emissions from the combustion of biomass fuels other
than spent liquor solids, as well as the combustion of biomass other
than spent liquor solids with other fuels. The proposed amendments
would provide a more accurate accounting of CO<INF>2</INF> and biogenic
CO<INF>2</INF> for subpart AA units in this situation. See section
III.I of this preamble for additional information.

D. Revisions To Reporting Requirements To Improve Verification and the
Accuracy of the Data Collected

In the 2022 Data Quality Improvements Proposal, the EPA proposed
several revisions to existing reporting requirements to improve the
quality of the data that are currently reported, to collect more useful
data to improve verification of reported data, to better characterize
U.S. GHG emissions and trends, and to extend the usefulness of the
GHGRP to inform and improve the EPA's ability to carry out other CAA
programs. See section II.A.4 of the 2022 Data Quality Improvements
Proposal for additional information. In this supplemental proposal, the
EPA is proposing new revisions to reporting requirements where we have
identified additional data that would further support these goals and
improve the quality of the GHGRP.
In some cases, the EPA is proposing to collect additional
information that would better inform the development of GHG policies
and programs by providing information on GHG uses and their relative
importance in specific sectors. For example, we are proposing to add
reporting requirements to subpart OO (Suppliers of Industrial
Greenhouse Gases) to require industrial gas suppliers to identify the
end-use applications for which F-HTFs are used and the approximate
quantities used in each application. The EPA recently proposed a
similar requirement for N<INF>2</INF>O, PFCs, and SF<INF>6</INF> in the
2022 Data Quality Improvements Proposal; this supplemental notification
extends the proposed revisions to include F-HTFs

[[Page 32862]]

to better account for emissions from the use and distribution of F-HTFs
which are not otherwise accounted for in the current source categories
under part 98. See section III.K of this preamble for additional
information.
The proposed revisions would also provide more useful data that
would improve verification of reported data. For example, we are
proposing to revise the existing reporting and recordkeeping
requirements in subpart N (Glass Production) for both facilities using
continuous electronic monitoring systems (CEMS) and non-CEMS facilities
(i.e., facilities that use a mass balance calculation method) to
require reporting and recordkeeping of the annual amounts of recycled
scrap glass (cullet) used as a raw material. The EPA is proposing to
collect this information because the use of cullet, which contains no
carbonates that can be converted to CO<INF>2</INF> emissions, can lead
to reductions in emissions from the production of various glass types.
The proposed data element would help to inform the EPA's understanding
of the variations and differences in emissions estimates within this
sector, improve understanding of industry trends, and improve
verification of collected data. As discussed in section II of this
preamble and in prior amendments, the GHGRP is intended to supplement
and complement other EPA programs by advancing the understanding of
emission processes and monitoring methodologies for particular source
categories or sectors.
Similarly, for subpart Y (Petroleum Refineries), we are proposing
to include a requirement to report the capacity of each asphalt blowing
unit. Although subpart Y currently includes unit-level capacity
reporting requirements for other emission units (e.g., catalytic
cracking units, fluid coking units, sulfur recovery plants, coke
calcining units, delayed coking units), the EPA lacks data on the
capacities of asphalt blowing units. Individual unit information allows
the EPA to aggregate emissions according to unit type and size and
provides a better understanding of the emissions from specific unit
types. Therefore, the proposed revisions to subpart Y would improve
emissions analysis and verification for these units.
The proposed changes to reporting requirements in this supplemental
notification would further enable the EPA to obtain data that is of
sufficient quality that it can be used to support a range of future
climate change policies and regulations, in keeping with the EPA's CAA
section 114 authorities.

E. Technical Amendments, Clarifications, and Corrections

This supplemental proposal includes several other proposed
technical amendments, corrections, and clarifications that have been
identified following the 2022 Data Quality Improvements Proposal and
that would improve understanding of the rule. The proposed amendments
include revisions that better reflect the EPA's intent and include
editorial changes, revisions that resolve uncertainties in the
regulatory text, and amendments that would increase the likelihood that
reporters will submit accurate reports. Some of the proposed changes
result from consideration of questions raised by reporters through the
GHGRP Help Desk or e-GGRT. For example, we are proposing to add a
definition for the term ``offshore'' to subpart RR (Geologic
Sequestration of Carbon Dioxide) to clarify questions raised by
stakeholders regarding the applicability of subpart RR to specific
offshore geologic sequestration activities. Although the EPA previously
noted that the source category covers both onshore and offshore
injection of CO<INF>2</INF> in its 2010 final rule (75 FR 75060,
December 1, 2010), we are aware that we have not previously provided a
definition for the term ``offshore.'' The proposed definition would
clarify the boundaries of injection activities that are currently
covered under the source category and improve reporting to the GHGRP.
We are proposing similar revisions to clarify definitions. For
example, we are proposing to revise subpart A (General Provisions) to
amend the definition of the term ``Bulk'' to address questions raised
by certain suppliers as to whether imports or exports of GHGs in small
containers are reportable to the GHGRP. The proposed revision is a
clarification of the existing definition and would provide clarity
regarding the size of containers that should be included in the
reported supply.
Finally, the EPA is proposing minor changes such as edits to fix
typos, minor clarifications such as adding a missing word, and
harmonizing changes to match other proposed revisions. For example, we
are clarifying the 2022 Data Quality Improvements Proposal regarding
proposed destruction and removal efficiency (DRE) and gamma factors in
Tables I-16 and I-18 of subpart I (Electronics Manufacturing),
respectively, to correct inadvertent errors in the relevant proposed
regulatory text. We are also proposing to correct subpart AA (Pulp and
Paper Manufacturing) at 40 CFR 98.276 to correct a reporting
requirement that incorrectly refers to biogenic CH<INF>4</INF> and
N<INF>2</INF>O. All proposed minor corrections and clarifications are
reflected in the draft proposed redline regulatory text in the docket
for this rulemaking (Docket Id. No. EPA-HQ-OAR-2019-0424).

III. Proposed Amendments to Part 98

This section summarizes the specific substantive amendments
proposed for each subpart, as generally described in section II of this
preamble. The impacts of the proposed revisions are summarized in
section VII of this preamble. A full discussion of the cost impacts for
the proposed revisions may be found in the memorandum, Assessment of
Burden Impacts for Proposed Supplemental Revisions for the Greenhouse
Gas Reporting Rule, available in the docket for this rulemaking (Docket
Id. No. EPA-HQ-OAR-2019-0424).

A. Subpart A--General Provisions

1. Proposed Revisions to Global Warming Potentials in Table A-1
For the reasons described here and in section II.A of this
preamble, we are proposing to revise Table A-1 to subpart A of part 98
(General Provisions) to update the GWP values of certain GHGs to
reflect GWPs from Table 8.A.1 of AR5 and, for certain GHGs that do not
have GWPs listed in AR5, to adopt GWP values from AR6. We are also
proposing to add default GWPs for two new fluorinated GHG groups, to
slightly modify an existing GHG group, and to update the default GWPs
for all the existing fluorinated GHG groups. The chemical-specific GWP
values currently in Table A-1 are drawn both from AR4 and, for multiple
GHGs that do not have GWPs listed in AR4, from AR5. The current GWPs
drawn from AR4 would be updated to values from AR5, while the current
GWPs drawn from AR5 would remain the same. AR6 GWPs would be added for
GHGs that do not have GWPs listed in AR5. Under the current rule,
default GWPs are applied to GHGs that do not have GWPs listed in AR5
based on the fluorinated GHG group to which they belong.
By proposing (1) to adopt (or maintain) AR5 GWPs for GHGs that have
GWPs listed in AR5, and (2) to adopt AR6 GWPs for GHGs that do not have
GWPs listed in AR5, we are taking the approach to establishing and
updating GWPs that we have taken since the beginning of the GHGRP. That
is, for GHGs with GWPs listed in the IPCC Assessment Report that the
parties to the UNFCCC have agreed to use as the source of GWPs, we are
proposing to use the GWPs in the agreed-upon

[[Page 32863]]

Assessment Report to maintain consistency with the Inventory and other
analyses. For GHGs that do not have GWPs listed in the agreed-upon
Assessment Report, but that do have GWPs listed in a more recent IPCC
Assessment Report, we are proposing to use the GWPs in the most recent
report to increase the accuracy of the calculations and reporting under
part 98. Where the UNFCCC-referenced Assessment Report does not include
a GWP for a GHG, adopting the GWP from a more recent Assessment Report
does not introduce inconsistency with Inventory reporting. In fact, as
noted in the 2014 Fluorinated GHG Final Rule updating GWPs, adopting
GWPs in the most recent Scientific Assessment Report would facilitate
U.S. reporting under the UNFCCC Reporting Guidelines, which state:
``Annex I Parties are strongly encouraged to also report emissions and
removals of additional GHGs, such as hydrofluoroethers (HFEs),
perfluoropolyethers (PFPEs), and other gases for which 100-year global
warming potential values are available from the IPCC but have not yet
been adopted by the [Conference of the Parties to the UNFCCC].'' \18\
---------------------------------------------------------------------------

\18\ See Decision 24, CP.19 at <a href="https://unfccc.int/resource/docs/2013/cop19/eng/10a03.pdf">https://unfccc.int/resource/docs/2013/cop19/eng/10a03.pdf</a>.
---------------------------------------------------------------------------

Specifically, the first set of GWPs adopted under part 98 in 2009
consisted of (1) GWPs from the SAR for GHGs that had GWPs listed in the
SAR (consistent with the UNFCCC reporting guidelines in effect at the
time) and (2) GWPs from AR4 (the most recent IPCC Assessment Report
available at the time) for GHGs that did not have GWPs listed in the
SAR.\19\ The second set of GWPs adopted under part 98, in 2013 and
2014, consisted of (1) GWPs from AR4 (consistent with the UNFCCC
reporting guidelines going into effect at the time), and (2) GWPs from
AR5 (the most recent IPCC Assessment Report available at the time) for
GHGs that did not have GWPs listed in AR4.
---------------------------------------------------------------------------

\19\ Mandatory Reporting of Greenhouse Gases, proposed pule
published on April 10, 2009 (74 FR 16453).
---------------------------------------------------------------------------

Two decisions by the parties to the UNFCCC require countries to use
the AR5 values from Table 8.A.1 for their Inventories and other
reporting, beginning with the reports due in 2024. Decision 18/CMA.1,
annex, paragraph 37 (December, 2018) reads, ``Each Party shall use the
100-year time-horizon global warming potential (GWP) values from the
IPCC Fifth Assessment Report, or 100-year time-horizon GWP values from
a subsequent IPCC assessment report as agreed upon by the [Conference
of the Parties serving as the meeting of the Parties to the Paris
Agreement] (CMA), to report aggregate emissions and removals of GHGs,
expressed in CO<INF>2</INF> eq.'' Decision 5/CMA.3, paragraph 25
(November, 2021) reads, ``the 100-year time-horizon global warming
potential values referred to in decision 18/CMA.1, annex, paragraph 37,
shall be those listed in Table 8.A.1 of the Fifth Assessment Report of
the Intergovernmental Panel on Climate Change, excluding the value for
fossil methane.'' \20\
---------------------------------------------------------------------------

\20\ Refer to <a href="https://unfccc.int/">https://unfccc.int/</a>.
---------------------------------------------------------------------------

The second decision, specifying that Parties must use the GWP
values in Table 8.A.1 of AR5, excluding the value for ``fossil
methane,'' was important for two reasons. First, AR5 includes two
tables of GWPs. Table 8.A.1 includes GWPs that reflect the climate-
carbon feedbacks of CO<INF>2</INF> but not the GHG whose GWP is being
evaluated, while the other table includes GWPs that reflect the
climate-carbon feedbacks of both CO<INF>2</INF> and the GHG whose GWP
is being evaluated. (The same GHGs are in both tables.) Second, for
methane, AR5 includes two GWP values in each table. In each table, one
methane GWP accounts for the influence of CO<INF>2</INF> produced by
the oxidation of methane (the value for ``fossil'' methane) and one
methane GWP does not account for the influence of CO<INF>2</INF>
produced by the oxidation of methane.
Consistent with the 2021 UNFCCC decision, we are proposing to use
(1) for GHGs with GWPs in AR5, the AR5 GWP values in Table 8.A.1 (that
reflect the climate-carbon feedbacks of CO<INF>2</INF> but not the GHG
whose GWP is being evaluated), and (2) for methane, the GWP that is not
the GWP for fossil methane in Table 8.A.1 (i.e., the GWP for methane
that does not reflect either the climate-carbon feedbacks for methane
or the atmospheric CO<INF>2</INF> that would result from the oxidation
of methane in the atmosphere). In addition to maintaining consistency
with recent UNFCCC decisions, using a single GWP for methane that does
not reflect the CO<INF>2</INF> oxidation product would be consistent
with prior IPCC practice, avoid the potential for double counting, and
reduce complexity in accounting.\21\
---------------------------------------------------------------------------

\21\ Paragraph 52 of the annex to 18/CMA.1 encourages parties to
the UNFCCC to report indirect CO<INF>2</INF> emissions separately:
``Each Party may report indirect CO2 from the atmospheric oxidation
of CH4, CO and NMVOCs. For Parties that decide to report indirect
CO2, the national totals shall be presented with and without
indirect CO<INF>2</INF>.'' Refer to <a href="https://unfccc.int/">https://unfccc.int/</a>. Using the
fossil methane GWP, which incorporates the impact of the indirect
CO<INF>2</INF>, would double count those emissions.
---------------------------------------------------------------------------

As noted above, we are also proposing to adopt AR6 GWPs for 31 GHGs
that have GWPs listed in AR6 but not AR5. All of these are fluorinated
GHGs. Currently, default GWPs based on each GHG's fluorinated GHG group
are applied to these GHGs. Each default value reflects the average of
the known GWPs of the GHGs in a group of chemically similar fluorinated
GHGs. While the default value is expected to be an unbiased estimate of
the GWPs of other fluorinated GHGs in that group, it is not expected to
be as accurate as a chemical-specific GWP for any given GHG, which
reflects the radiative efficiency and atmospheric lifetime of that GHG.
The chemical-specific GWPs in each group vary over a range. For
example, the chemical-specific AR5 GWPs in each group show relative
standard deviations between 30 and 170 percent, depending on the group.
Thus, using chemical-specific GWPs instead of default values would
better reflect the atmospheric impacts of these gases.
The AR6 GWPs reflect the climate-carbon feedbacks for the GHG whose
GWP is being evaluated, while the AR5 GWPs that we are proposing to
adopt (from Table 8.A.1) do not. GWPs that reflect the climate-carbon
feedbacks for the GHG whose GWP is being evaluated are slightly larger
than GWPs that do not. Thus, this difference could potentially result
in over-weighting the atmospheric impacts of GHGs whose GWPs are drawn
from AR6 relative to GHGs whose GWPs are drawn from Table 8.A.1 of AR5.
However, our analysis indicates that using chemical-specific GWPs will
lead to more accurate estimates, even if there are some inconsistencies
among those GWPs.\22\ In AR5, reflecting climate-carbon feedbacks for
the GHG whose GWP is being evaluated results in an increase in the
evaluated GWP of 11 to 22 percent, with the higher fractional increase
being associated with shorter-lived gases with lower GWPs.\23\ In
contrast, using default GWPs based on AR5 rather than chemical-specific
GWPs from AR6 would result in overestimating GWPs by as much as 3,000
(equivalent to a relative error of 1,200 percent) and underestimating
GWPs by as much as 5,000 (equivalent to a relative error of -35
percent), with over- and underestimates averaging 1,200 and 950
respectively (and relative

[[Page 32864]]

errors averaging 770 percent and -60 percent, respectively).\24\
Overall, these potential errors are substantially larger than the
differences between GWPs that do and do not reflect climate-carbon
feedbacks for the GHGs whose GWPs were evaluated.
---------------------------------------------------------------------------

\22\ See the memorandum, Proposed Updates to Chemical-Specific
and Default GWPs for the Greenhouse Gas Reporting Rule, available in
the docket for this rulemaking (Docket Id. No. EPA-HQ-OAR-2019-
0424).
\23\ The authors of AR6 estimated smaller impacts from climate-
carbon feedbacks, meaning that the difference between accounting and
not accounting for them is likely smaller than 11 to 22 percent.
(See AR6, Chapter 7, page 121.)
\24\ To avoid skewing the results with inconsequential
differences, instances where the default GWP would differ from the
chemical-specific GWP by less than one were excluded from the
analysis. In all these cases, the default GWP was one.
---------------------------------------------------------------------------

Table 2 of this preamble lists the GHGs whose GWP values we are
proposing to revise, along with the GWP values currently listed in
Table A-1 and the proposed revised GWP values based on either AR5 or
AR6. Additional information regarding the EPA's rationale for the
proposed GWPs may be found in the memorandum, Proposed Updates to
Chemical-Specific and Default GWPs for the Greenhouse Gas Reporting
Rule, in the docket for this rulemaking, (Docket Id. No. EPA-HQ-OAR-
2019-0424).

Table 2--Proposed Revised Chemical-Specific GWPs for Compounds in Table A-1
----------------------------------------------------------------------------------------------------------------
Current global Proposed
warming global warming
Name CAS No. Chemical formula potential (100 potential (100
yr.) yr.)
----------------------------------------------------------------------------------------------------------------
Chemical-Specific GWPs
----------------------------------------------------------------------------------------------------------------
Carbon dioxide...................... 124-38-9 CO2.................... 1 1
Methane............................. 74-82-8 CH4.................... 25 28
Nitrous oxide....................... 10024-97-2 N2O.................... 298 265
----------------------------------------------------------------------------------------------------------------
Fully Fluorinated GHGs
----------------------------------------------------------------------------------------------------------------
Sulfur hexafluoride................. 2551-62-4 SF6.................... 22,800 23,500
Trifluoromethyl sulphur 373-80-8 SF5CF3................. 17,700 17,400
pentafluoride.
Nitrogen trifluoride................ 7783-54-2 NF3.................... 17,200 16,100
PFC-14 (Perfluoromethane)........... 75-73-0 CF4.................... 7,390 6,630
PFC-116 (Perfluoroethane)........... 76-16-4 C2F6................... 12,200 11,100
PFC-218 (Perfluoropropane).......... 76-19-7 C3F8................... 8,830 8,900
Perfluorocyclopropane............... 931-91-9 c-C3F6................. 17,340 9,200
PFC-3-1-10 (Perfluorobutane)........ 355-25-9 C4F10.................. 8,860 9,200
PFC-318 (Perfluorocyclobutane)...... 115-25-3 c-C4F8................. 10,300 9,540
Perfluorotetrahydrofuran............ 773-14-8 c-C4F8O................ * 10,000 13,900
PFC-4-1-12 (Perfluoropentane)....... 678-26-2 C5F12.................. 9,160 8,550
PFC-5-1-14 (Perfluorohexane, FC-72). 355-42-0 C6F14.................. 9,300 7,910
PFC-6-1-12.......................... 335-57-9 C7F16; CF3(CF2)5CF3.... 7,820 7,820
PFC-7-1-18.......................... 307-34-6 C8F18; CF3(CF2)6CF3.... 7,620 7,620
PFC-9-1-18.......................... 306-94-5 C10F18................. 7,500 7,190
PFPMIE (HT-70)...................... NA CF3OCF(CF3)CF2OCF2OCF3. 10,300 9,710
Perfluorodecalin (cis).............. 60433-11-6 Z-C10F18............... 7,236 7,240
Perfluorodecalin (trans)............ 60433-12-7 E-C10F18............... 6,288 6,290
Perfluorotriethylamine.............. 359-70-6 N(C2F5)3............... * 10,000 10,300
Perfluorotripropylamine............. 338-83-0 N(CF2CF2CF3)3.......... * 10,000 9,030
Perfluorotributylamine.............. 311-89-7 N(CF2CF2CF2CF3)3....... * 10,000 8,490
Perfluorotripentylamine............. 338-84-1 N(CF2CF2CF2CF2CF3)3.... * 10,000 7,260
----------------------------------------------------------------------------------------------------------------
Saturated Hydrofluorocarbons (HFCs) With Two or Fewer Carbon-Hydrogen Bonds
----------------------------------------------------------------------------------------------------------------
(4s,5s)-1,1,2,2,3,3,4,5- 158389-18-5 trans-cyc (- * 3,700 258
octafluorocyclopentane. CF2CF2CF2CHFCHF-).
HFC-23.............................. 75-46-7 CHF3................... 14,800 12,400
HFC-32.............................. 75-10-5 CH2F2.................. 675 677
HFC-125............................. 354-33-6 C2HF5.................. 3,500 3,170
HFC-134............................. 359-35-3 C2H2F4................. 1,100 1,120
HFC-134a............................ 811-97-2 CH2FCF3................ 1,430 1,300
HFC-227ca........................... 2252-84-8 CF3CF2CHF2............. 2,640 2,640
HFC-227ea........................... 431-89-0 C3HF7.................. 3,220 3,350
HFC-236cb........................... 677-56-5 CH2FCF2CF3............. 1,340 1,210
HFC-236ea........................... 431-63-0 CHF2CHFCF3............. 1,370 1,330
HFC-236fa........................... 690-39-1 C3H2F6................. 9,810 8,060
HFC-329p............................ 375-17-7 CHF2CF2CF2CF3.......... 2,360 2,360
HFC-43-10mee........................ 138495-42-8 CF3CFHCFHCF2CF3........ 1,640 1,650
----------------------------------------------------------------------------------------------------------------
Saturated Hydrofluorocarbons (HFCs) With Three or More Carbon-Hydrogen Bonds
----------------------------------------------------------------------------------------------------------------
1,1,2,2,3,3-hexafluorocyclopentane.. 123768-18-3 cyc (-CF2CF2CF2CH2CH2-) * 930 120
1,1,2,2,3,3,4- 15290-77-4 cyc (-CF2CF2CF2CHFCH2-) * 930 231
heptafluorocyclopentane.
HFC-41.............................. 593-53-3 CH3F................... 92 116
HFC-143............................. 430-66-0 C2H3F3................. 353 328
HFC-143a............................ 420-46-2 C2H3F3................. 4,470 4,800
HFC-152............................. 624-72-6 CH2FCH2F............... 53 16
HFC-152a............................ 75-37-6 CH3CHF2................ 124 138
HFC-161............................. 353-36-6 CH3CH2F................ 12 4

[[Page 32865]]

HFC-245ca........................... 679-86-7 C3H3F5................. 693 716
HFC-245cb........................... 1814-88-6 CF3CF2CH3.............. 4,620 4,620
HFC-245ea........................... 24270-66-4 CHF2CHFCHF2............ 235 235
HFC-245eb........................... 431-31-2 CH2FCHFCF3............. 290 290
HFC-245fa........................... 460-73-1 CHF2CH2CF3............. 1,030 858
HFC-263fb........................... 421-07-8 CH3CH2CF3.............. 76 76
HFC-272ca........................... 420-45-1 CH3CF2CH3.............. 144 144
HFC-365mfc.......................... 406-58-6 CH3CF2CH2CF3........... 794 804
----------------------------------------------------------------------------------------------------------------
Saturated Hydrofluoroethers (HFEs) and Hydrochlorofluoroethers (HCFEs) With One Carbon-Hydrogen Bond
----------------------------------------------------------------------------------------------------------------
HFE-125............................. 3822-68-2 CHF2OCF3............... 14,900 12,400
HFE-227ea........................... 2356-62-9 CF3CHFOCF3............. 1,540 6,450
HFE-329mcc2......................... 134769-21-4 CF3CF2OCF2CHF2......... 919 3,070
HFE-329me3.......................... 428454-68-6 CF3CFHCF2OCF3.......... 4,550 4,550
1,1,1,2,2,3,3-Heptafluoro-3-(1,2,2,2- 3330-15-2 CF3CF2CF2OCHFCF3....... 6,490 6,490
tetrafluoroethoxy)-propane.
----------------------------------------------------------------------------------------------------------------
Saturated HFEs and HCFEs With Two Carbon-Hydrogen Bonds
----------------------------------------------------------------------------------------------------------------
HFE-134 (HG-00)..................... 1691-17-4 CHF2OCHF2.............. 6,320 5,560
HFE-236ca........................... 32778-11-3 CHF2OCF2CHF2........... 4,240 4,240
HFE-236ca12 (HG-10)................. 78522-47-1 CHF2OCF2OCHF2.......... 2,800 5,350
HFE-236ea2 (Desflurane)............. 57041-67-5 CHF2OCHFCF3............ 989 1,790
HFE-236fa........................... 20193-67-3 CF3CH2OCF3............. 487 979
HFE-338mcf2......................... 156053-88-2 CF3CF2OCH2CF3.......... 552 929
HFE-338mmz1......................... 26103-08-2 CHF2OCH(CF3)2.......... 380 2,620
HFE-338pcc13 (HG-01)................ 188690-78-0 CHF2OCF2CF2OCHF2....... 1,500 2,910
HFE-43-10pccc (H-Galden 1040x, HG- E1730133 CHF2OCF2OC2F4OCHF2..... 1,870 2,820
11).
HCFE-235ca2 (Enflurane)............. 13838-16-9 CHF2OCF2CHFCl.......... 583 583
HCFE-235da2 (Isoflurane)............ 26675-46-7 CHF2OCHClCF3........... 350 491
HG-02............................... 205367-61-9 HF2C-(OCF2CF2)2-OCF2H.. 3,825 2,730
HG-03............................... 173350-37-3 HF2C-(OCF2CF2)3-OCF2H.. 3,670 2,850
HG-20............................... 249932-25-0 HF2C-(OCF2)2-OCF2H..... 5,300 5,300
HG-21............................... 249932-26-1 HF2C-OCF2CF2OCF2OCF2O- 3,890 3,890
CF2H.
HG-30............................... 188690-77-9 HF2C-(OCF2)3-OCF2H..... 7,330 7,330
1,1,3,3,4,4,6,6,7,7,9,9,10,10,12,12, 173350-38-4 HCF2O(CF2CF2O)4CF2H.... 3,630 3,630
13,13,15,15-eicosafluoro-
2,5,8,11,14-Pentaoxapentadecane.
1,1,2-Trifluoro-2-(trifluoromethoxy)- 84011-06-3 CHF2CHFOCF3............ 1,240 1,240
ethane.
Trifluoro(fluoromethoxy)methane..... 2261-01-0 CH2FOCF3............... 751 751
----------------------------------------------------------------------------------------------------------------
Saturated HFEs and HCFEs With Three or More Carbon-Hydrogen Bonds
----------------------------------------------------------------------------------------------------------------
HFE-143a............................ 421-14-7 CH3OCF3................ 756 523
HFE-245cb2.......................... 22410-44-2 CH3OCF2CF3............. 708 654
HFE-245fa1.......................... 84011-15-4 CHF2CH2OCF3............ 286 828
HFE-245fa2.......................... 1885-48-9 CHF2OCH2CF3............ 659 812
HFE-254cb2.......................... 425-88-7 CH3OCF2CHF2............ 359 301
HFE-263fb2.......................... 460-43-5 CF3CH2OCH3............. 11 1
HFE-263m1; R-E-143a................. 690-22-2 CF3OCH2CH3............. 29 29
HFE-347mcc3 (HFE-7000).............. 375-03-1 CH3OCF2CF2CF3.......... 575 530
HFE-347mcf2......................... 171182-95-9 CF3CF2OCH2CHF2......... 374 854
HFE-347mmy1......................... 22052-84-2 CH3OCF(CF3)2........... 343 363
HFE-347mmz1 (Sevoflurane)........... 28523-86-6 (CF3)2CHOCH2F.......... 216 216
HFE-347pcf2......................... 406-78-0 CHF2CF2OCH2CF3......... 580 889
HFE-356mec3......................... 382-34-3 CH3OCF2CHFCF3.......... 101 387
HFE-356mff2......................... 333-36-8 CF3CH2OCH2CF3.......... 17 17
HFE-356mmz1......................... 13171-18-1 (CF3)2CHOCH3........... 27 14
HFE-356pcc3......................... 160620-20-2 CH3OCF2CF2CHF2......... 110 413
HFE-356pcf2......................... 50807-77-7 CHF2CH2OCF2CHF2........ 265 719
HFE-356pcf3......................... 35042-99-0 CHF2OCH2CF2CHF2........ 502 446
HFE-365mcf2......................... 22052-81-9 CF3CF2OCH2CH3.......... 58 58
HFE-365mcf3......................... 378-16-5 CF3CF2CH2OCH3.......... 11 0.99
HFE-374pc2.......................... 512-51-6 CH3CH2OCF2CHF2......... 557 627
HFE-449s1 (HFE-7100) Chemical blend. 163702-07-6 C4F9OCH3............... 297 421
163702-08-7 (CF3)2CFCF2OCH3........ .............. ..............
HFE-569sf2 (HFE-7200) Chemical blend 163702-05-4 C4F9OC2H5.............. 59 57
163702-06-5 (CF3)2CFCF2OC2H5....... .............. ..............
HFE-7300............................ 132182-92-4 (CF3)2CFCFOC2H5CF2CF2CF * 270 405
3.

[[Page 32866]]

HFE-7500............................ 297730-93-9 n-C3F7CFOC2H5CF(CF3)2.. * 270 13
HG'-01.............................. 73287-23-7 CH3OCF2CF2OCH3......... 222 222
HG'-02.............................. 485399-46-0 CH3O(CF2CF2O)2CH3...... 236 236
HG'-03.............................. 485399-48-2 CH3O(CF2CF2O)3CH3...... 221 221
Difluoro(methoxy)methane............ 359-15-9 CH3OCHF2............... 144 144
2-Chloro-1,1,2-trifluoro-1- 425-87-6 CH3OCF2CHFCl........... 122 122
methoxyethane.
1-Ethoxy-1,1,2,2,3,3,3- 22052-86-4 CF3CF2CF2OCH2CH3....... 61 61
heptafluoropropane.
2-Ethoxy-3,3,4,4,5- 920979-28-8 C12H5F19O2............. 56 56
pentafluorotetrahydro-2,5-
bis[1,2,2,2-tetrafluoro-1-
(trifluoromethyl)ethyl]-furan.
1-Ethoxy-1,1,2,3,3,3- 380-34-7 CF3CHFCF2OCH2CH3....... 23 23
hexafluoropropane.
Fluoro(methoxy)methane.............. 460-22-0 CH3OCH2F............... 13 13
1,1,2,2-Tetrafluoro-3-methoxy- 60598-17-6 CHF2CF2CH2OCH3......... 0.5 0.49
propane; Methyl 2,2,3,3-
tetrafluoropropyl ether.
1,1,2,2-Tetrafluoro-1- 37031-31-5 CH2FOCF2CF2H........... 871 871
(fluoromethoxy)ethane.
Difluoro(fluoromethoxy)methane...... 461-63-2 CH2FOCHF2.............. 617 617
Fluoro(fluoromethoxy)methane........ 462-51-1 CH2FOCH2F.............. 130 130
----------------------------------------------------------------------------------------------------------------
Saturated Chlorofluorocarbons (CFCs)
----------------------------------------------------------------------------------------------------------------
E-R316c............................. 3832-15-3 trans-cyc (- * 2000 4,230
CClFCF2CF2CClF-).
Z-R316c............................. 3934-26-7 cis-cyc (- * 2000 5,660
CClFCF2CF2CClF-).
----------------------------------------------------------------------------------------------------------------
Fluorinated Formates
----------------------------------------------------------------------------------------------------------------
Trifluoromethyl formate............. 85358-65-2 HCOOCF3................ 588 588
Perfluoroethyl formate.............. 313064-40-3 HCOOCF2CF3............. 580 580
1,2,2,2-Tetrafluoroethyl formate.... 481631-19-0 HCOOCHFCF3............. 470 470
Perfluorobutyl formate.............. 197218-56-7 HCOOCF2CF2CF2CF3....... 392 392
Perfluoropropyl formate............. 271257-42-2 HCOOCF2CF2CF3.......... 376 376
1,1,1,3,3,3-Hexafluoropropan-2-yl 856766-70-6 HCOOCH(CF3)2........... 333 333
formate.
2,2,2-Trifluoroethyl formate........ 32042-38-9 HCOOCH2CF3............. 33 33
3,3,3-Trifluoropropyl formate....... 1344118-09-7 HCOOCH2CH2CF3.......... 17 17
----------------------------------------------------------------------------------------------------------------
Fluorinated Acetates
----------------------------------------------------------------------------------------------------------------
Methyl 2,2,2-trifluoroacetate....... 431-47-0 CF3COOCH3.............. 52 52
1,1-Difluoroethyl 2,2,2- 1344118-13-3 CF3COOCF2CH3........... 31 31
trifluoroacetate.
Difluoromethyl 2,2,2- 2024-86-4 CF3COOCHF2............. 27 27
trifluoroacetate.
2,2,2-Trifluoroethyl 2,2,2- 407-38-5 CF3COOCH2CF3........... 7 7
trifluoroacetate.
Methyl 2,2-difluoroacetate.......... 433-53-4 HCF2COOCH3............. 3 3
Perfluoroethyl acetate.............. 343269-97-6 CH3COOCF2CF3........... 2.1 2
Trifluoromethyl acetate............. 74123-20-9 CH3COOCF3.............. 2.0 2
Perfluoropropyl acetate............. 1344118-10-0 CH3COOCF2CF2CF3........ 1.8 2
Perfluorobutyl acetate.............. 209597-28-4 CH3COOCF2CF2CF2CF3..... 1.6 2
Ethyl 2,2,2-trifluoroacetate........ 383-63-1 CF3COOCH2CH3........... 1.3 1
----------------------------------------------------------------------------------------------------------------
Carbonofluoridates
----------------------------------------------------------------------------------------------------------------
Methyl carbonofluoridate............ 1538-06-3 FCOOCH3................ 95 95
1,1-Difluoroethyl carbonofluoridate. 1344118-11-1 FCOOCF2CH3............. 27 27
----------------------------------------------------------------------------------------------------------------
Fluorinated Alcohols Other Than Fluorotelomer Alcohols
----------------------------------------------------------------------------------------------------------------
Bis(trifluoromethyl)-methanol....... 920-66-1 (CF3)2CHOH............. 195 182
2,2,3,3,4,4,5,5- 16621-87-7 cyc (-(CF2)4CH(OH)-)... 73 13
Octafluorocyclopentanol.
2,2,3,3,3-Pentafluoropropanol....... 422-05-9 CF3CF2CH2OH............ 42 19
2,2,3,3,4,4,4-Heptafluorobutan-1-ol. 375-01-9 C3F7CH2OH.............. 25 34
2,2,2-Trifluoroethanol.............. 75-89-8 CF3CH2OH............... 20 20
2,2,3,4,4,4-Hexafluoro-1-butanol.... 382-31-0 CF3CHFCF2CH2OH......... 17 17
2,2,3,3-Tetrafluoro-1-propanol...... 76-37-9 CHF2CF2CH2OH........... 13 13
2,2-Difluoroethanol................. 359-13-7 CHF2CH2OH.............. 3 3
2-Fluoroethanol..................... 371-62-0 CH2FCH2OH.............. 1.1 1.1
4,4,4-Trifluorobutan-1-ol........... 461-18-7 CF3(CH2)2CH2OH......... 0.05 0.05
----------------------------------------------------------------------------------------------------------------
Non-Cyclic, Unsaturated Perfluorocarbons (PFCs)
----------------------------------------------------------------------------------------------------------------
PFC-1114; TFE....................... 116-14-3 CF2=CF2; C2F4.......... 0.004 0.004
PFC-1216; Dyneon HFP................ 116-15-4 C3F6; CF3CF=CF2........ 0.05 0.05

[[Page 32867]]

Perfluorobut-2-ene.................. 360-89-4 CF3CF=CFCF3............ 1.82 1.82
Perfluorobut-1-ene.................. 357-26-6 CF3CF2CF=CF2........... 0.10 0.10
Perfluorobuta-1,3-diene............. 685-63-2 CF2=CFCF=CF2........... 0.003 0.003
----------------------------------------------------------------------------------------------------------------
Non-Cyclic, Unsaturated Hydrofluorocarbons (HFCs) and Hydrochlorofluorocarbons (HCFCs)
----------------------------------------------------------------------------------------------------------------
HFC-1132a; VF2...................... 75-38-7 C2H2F2, CF2=CH2........ 0.04 0.04
HFC-1141; VF........................ 75-02-5 C2H3F, CH2=CHF......... 0.02 0.02
(E)-HFC-1225ye...................... 5595-10-8 CF3CF=CHF(E)........... 0.06 0.06
(Z)-HFC-1225ye...................... 5528-43-8 CF3CF=CHF(Z)........... 0.22 0.22
Solstice 1233zd(E).................. 102687-65-0 C3H2ClF3; CHCl=CHCF3... 1.34 1.34
HCFO-1233zd(Z)...................... 99728-16-2 (Z)-CF3CH=CHCl......... * 1 0.45
HFC-1234yf; HFO-1234yf.............. 754-12-1 C3H2F4; CF3CF=CH2...... 0.31 0.31
HFC-1234ze(E)....................... 1645-83-6 C3H2F4; trans-CF3CH=CHF 0.97 0.97
HFC-1234ze(Z)....................... 29118-25-0 C3H2F4; cis-CF3CH=CHF; 0.29 0.29
CF3CH=CHF.
HFC-1243zf; TFP..................... 677-21-4 C3H3F3, CF3CH=CH2...... 0.12 0.12
(Z)-HFC-1336........................ 692-49-9 CF3CH=CHCF3(Z)......... 1.58 1.58
HFO-1336mzz(E)...................... 66711-86-2 (E)-CF3CH=CHCF3........ * 1 18
HFC-1345zfc......................... 374-27-6 C2F5CH=CH2............. 0.09 0.09
HFO-1123............................ 359-11-5 CHF=CF2................ * 1 0.005
HFO-1438ezy(E)...................... 14149-41-8 (E)-(CF3)2CFCH=CHF..... * 1 8.2
HFO-1447fz.......................... 355-08-8 CF3(CF2)2CH=CH2........ * 1 0.24
Capstone 42-U....................... 19430-93-4 C6H3F9, CF3(CF2)3CH=CH2 0.16 0.16
Capstone 62-U....................... 25291-17-2 C8H3F13, 0.11 0.11
CF3(CF2)5CH=CH2.
Capstone 82-U....................... 21652-58-4 C10H3F17, 0.09 0.09
CF3(CF2)7CH=CH2.
(e)-1-chloro-2-fluoroethene......... 460-16-2 (E)-CHCl=CHF........... * 1 0.004
3,3,3-trifluoro-2- 382-10-5 (CF3)2C=CH2............ * 1 0.38
(trifluoromethyl)prop-1-ene.
----------------------------------------------------------------------------------------------------------------
Non-Cyclic, Unsaturated CFCs
----------------------------------------------------------------------------------------------------------------
CFC-1112............................ 598-88-9 CClF=CClF.............. * 1 0.13
CFC-1112a........................... 79-35-6 CCl2=CF2............... * 1 0.021
----------------------------------------------------------------------------------------------------------------
Non-Cyclic, Unsaturated Halogenated Ethers
----------------------------------------------------------------------------------------------------------------
PMVE; HFE-216....................... 1187-93-5 CF3OCF=CF2............. 0.17 0.17
Fluoroxene.......................... 406-90-6 CF3CH2OCH=CH2.......... 0.05 0.05
Methyl-perfluoroheptene-ethers...... N/A CH3OC7F13.............. * 1 15
----------------------------------------------------------------------------------------------------------------
Non-Cyclic, Unsaturated Halogenated Esters
----------------------------------------------------------------------------------------------------------------
Ethenyl 2,2,2-trifluoroacetate...... 433-28-3 CF3COOCH=CH2........... * 1 0.008
Prop-2-enyl 2,2,2-trifluoroacetate.. 383-67-5 CF3COOCH2CH=CH2........ * 1 0.007
----------------------------------------------------------------------------------------------------------------
Cyclic, Unsaturated HFCs and PFCs
----------------------------------------------------------------------------------------------------------------
PFC C-1418.......................... 559-40-0 c-C5F8................. 1.97 2
Hexafluorocyclobutene............... 697-11-0 cyc (-CF=CFCF2CF2-).... * 1 126
1,3,3,4,4,5,5- 1892-03-1 cyc (-CF2CF2CF2CF=CH-). * 1 45
heptafluorocyclopentene.
1,3,3,4,4-pentafluorocyclobutene.... 374-31-2 cyc (-CH=CFCF2CF2-).... * 1 92
3,3,4,4-tetrafluorocyclobutene...... 2714-38-7 cyc (-CH=CHCF2CF2-).... * 1 26
----------------------------------------------------------------------------------------------------------------
Fluorinated Aldehydes
----------------------------------------------------------------------------------------------------------------
3,3,3-Trifluoro-propanal............ 460-40-2 CF3CH2CHO.............. 0.01 0.01
----------------------------------------------------------------------------------------------------------------
Fluorinated Ketones
----------------------------------------------------------------------------------------------------------------
Novec 1230 (perfluoro (2-methyl-3- 756-13-8 CF3CF2C(O)CF(CF3)2..... 0.1 0.1
pentanone)).
1,1,1-trifluoropropan-2-one......... 421-50-1 CF3COCH3............... * 1 0.09
1,1,1-trifluorobutan-2-one.......... 381-88-4 CF3COCH2CH3............ * 1 0.095
----------------------------------------------------------------------------------------------------------------
Fluorotelomer Alcohols
----------------------------------------------------------------------------------------------------------------
3,3,4,4,5,5,6,6,7,7,7- 185689-57-0 CF3(CF2)4CH2CH2OH...... 0.43 0.43
Undecafluoroheptan-1-ol.
3,3,3-Trifluoropropan-1-ol.......... 2240-88-2 CF3CH2CH2OH............ 0.35 0.35
3,3,4,4,5,5,6,6,7,7,8,8,9,9,9- 755-02-2 CF3(CF2)6CH2CH2OH...... 0.33 0.33
Pentadecafluorononan-1-ol.

[[Page 32868]]

3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11 87017-97-8 CF3(CF2)8CH2CH2OH...... 0.19 0.19
,11,11-Nonadecafluoroundecan-1-ol.
----------------------------------------------------------------------------------------------------------------
Fluorinated GHGs With Carbon-Iodine Bond(s)
----------------------------------------------------------------------------------------------------------------
Trifluoroiodomethane................ 2314-97-8 CF3I................... 0.4 0.4
----------------------------------------------------------------------------------------------------------------
Remaining Fluorinated GHGs With Chemical-Specific GWPs
----------------------------------------------------------------------------------------------------------------
Dibromodifluoromethane (Halon 1202). 75-61-6 CBr2F2................. 231 231
2-Bromo-2-chloro-1,1,1- 151-67-7 CHBrClCF3.............. 41 41
trifluoroethane (Halon-2311/
Halothane).
Heptafluoroisobutyronitrile......... 42532-60-5 (CF3)2CFCN............. * 2000 2,750
Carbonyl fluoride................... 353-50-4 COF2................... * 2000 ** 0.14
----------------------------------------------------------------------------------------------------------------
* Table A-1 does not include a chemical-specific value for this GHG; the value shown is the current default GWP
for the fluorinated GHG group of which the GHG is currently a member.
** Proposed in 2022 Data Quality Improvements Proposal.

We are also proposing to revise the default GWPs in Table A-1 by
adding two new fluorinated GHG groups, modifying an existing group, and
updating the existing default values to reflect the chemical-specific
GWPs that we are proposing to adopt from AR5 and AR6.\25\ The two new
groups that we are proposing to add are for saturated
chlorofluorocarbons (CFCs) and for cyclic forms of unsaturated
halogenated compounds. We have not previously included a group for
saturated CFCs because the GHGRP does not require reporting of most
CFCs. The GHGRP definition of ``fluorinated greenhouse gas'' (that is
itself referenced in the GHGRP definition of ``greenhouse gas'') at 40
CFR 98.6, includes ``sulfur hexafluoride (SF<INF>6</INF>), nitrogen
trifluoride (NF<INF>3</INF>), and any fluorocarbon except for
controlled substances as defined at 40 CFR part 82, subpart A and
substances with vapor pressures of less than 1 mm of Hg absolute at 25
degrees C.'' Although CFCs are fluorocarbons, most CFCs are defined as
``controlled substances'' under the EPA's ozone protection regulations
at 40 CFR part 82, excluding them from GHGRP coverage. However, some
CFCs are not defined as ``controlled substances'' under part 82 and are
therefore reportable under the GHGRP. These include two saturated CFCs
((E)-1,2-dichlorohexafluoro cyclobutane and (Z)-1,2-
dichlorohexafluorocyclobutane) and two unsaturated CFCs (CFC 1112 and
CFC 1112a) for which GWPs are provided in AR6. In the 2022 Data Quality
Improvements Proposal, we have proposed to include unsaturated CFCs
with unsaturated HFCs and PFCs in the current ninth fluorinated GHG
group, which is assigned a default GWP of 1. (The unsaturated CFCs both
have GWPs below 1.) The saturated CFCs have GWPs of 4,230 and 5,660
respectively, placing their proposed default GWP (4,900) between the
updated default GWPs proposed for saturated HFCs with two or fewer
carbon-hydrogen bonds (3,000) and for saturated HFEs and HCFEs with one
carbon-hydrogen bond (6,600). Given the numerical differences between
the GWP for the saturated CFC group and the GWPs for the other groups,
as well as the chemical differences between CFCs, HFCs, and HFEs, we
are proposing a separate group and separate default GWP for saturated
CFCs.
---------------------------------------------------------------------------

\25\ In the 2014 Fluorinated GHG Final Rule, we established 12
default GWPs intended for fluorinated GHGs and fluorinated HTFs for
which peer-reviewed GWPs were not available in AR4, AR5, or other
sources. The default GWPs were calculated based on the average of
the chemical-specific GWPs of the compounds in each fluorinated GHG
group. Each fluorinated GHG group is composed of compounds with
similar chemical structures, which have similar atmospheric
lifetimes and GWPs.
---------------------------------------------------------------------------

We are also proposing to establish a separate group for cyclic
unsaturated halogenated compounds, specifically, for the cyclic forms
of the following: unsaturated PFCs, unsaturated HFCs, unsaturated CFCs,
unsaturated hydrochlorofluorocarbons (HCFCs), unsaturated
bromofluorocarbons (BFCs), unsaturated bromochlorofluorocarbons
(BCFCs), unsaturated hydrobromofluorocarbons (HBFCs), unsaturated
hydrobromochlorofluoro carbons (HBCFCs), unsaturated halogenated
ethers, and unsaturated halogenated esters. AR6 includes GWPs for five
members of this set (all unsaturated HFCs or PFCs), ranging from 25.6
to 126. These GWPs are markedly larger than the GWPs for the non-cyclic
unsaturated halogenated compounds currently in the ninth fluorinated
GHG group, most of which are less than 1.\26\ The default GWP proposed
for the new group is 58, far higher than the value of 1 currently in
effect for the unsaturated halogenated compounds in the ninth
fluorinated GHG group. The new group would affect how the cyclic
unsaturated halogenated compounds are classified for reporting under
subparts A and L (Fluorinated Gas Production), and the corresponding
default GWP would be applied to cyclic unsaturated halogenated
compounds that do not have chemical-specific GWPs listed in AR5 or AR6.
One cyclic unsaturated PFC that is currently included in the
unsaturated group with the default GWP of 1, perfluorocyclopentene,
would be moved into the new group for purposes of classification and
calculation of the default GWP of the group.\27\
---------------------------------------------------------------------------

\26\ This is true for both the AR5 and AR6 GWP values for the
non-cyclic unsaturated compounds. Twenty-six of the 32 AR6 GWP
values for these compounds fall under 1 while six fall above 1, with
a maximum value of 18.
\27\ Perfluorocyclopentene is assigned GWP values of 2 and 78 in
AR5 and AR6 respectively. The AR5 value was used in the calculation
of the proposed default value for the cyclic unsaturated halogenated
compounds.
---------------------------------------------------------------------------

The proposed new and revised fluorinated GHG groups and their
proposed new and revised GWPs are listed in Table 3 of this preamble.

[[Page 32869]]

Table 3--Proposed Fluorinated GHG Groups and Default GWPs
------------------------------------------------------------------------
Current Proposed
global global
Fluorinated GHG group warming warming
potential potential
(100 yr.) (100 yr.)
------------------------------------------------------------------------
Fully fluorinated GHGs........................ 10,000 9,200
Saturated hydrofluorocarbons (HFCs) with two 3,700 3,000
or fewer carbon-hydrogen bonds...............
Saturated HFCs with three or more carbon- 930 840
hydrogen bonds...............................
Saturated hydrofluoroethers (HFEs) and 5,700 6,600
hydrochlorofluoroethers (HCFEs) with one
carbon-hydrogen bond.........................
Saturated HFEs and HCFEs with two carbon- 2,600 2,900
hydrogen bonds...............................
Saturated HFEs and HCFEs with three or more 270 320
carbon-hydrogen bonds........................
Saturated chlorofluorocarbons (CFCs).......... * 2,000 4,900
Fluorinated formates.......................... 350 350
Cyclic forms of the following: unsaturated ** 1 58
perfluorocarbons (PFCs), unsaturated HFCs,
unsaturated CFCs, unsaturated
hydrochlorofluorocarbons (HCFCs), unsaturated
bromofluorocarbons (BFCs), unsaturated
bromochlorofluorocarbons (BCFCs), unsaturated
hydrobromofluorocarbons (HBFCs), unsaturated
hydrobromochlorofluorocarbons (HBCFCs),
unsaturated halogenated ethers, and
unsaturated halogenated esters...............
Fluorinated acetates, carbonofluoridates, and 30 25
fluorinated alcohols other than fluorotelomer
alcohols.....................................
Fluorinated aldehydes, fluorinated ketones, 1 1
and non-cyclic forms of the following:
unsaturated PFCs, unsaturated HFCs,
unsaturated CFCs, unsaturated HCFCs,
unsaturated BFCs, unsaturated BCFCs,
unsaturated HBFCs, unsaturated HBCFCs,
unsaturated halogenated ethers, and
unsaturated halogenated esters...............
Fluorotelomer alcohols........................ 1 1
Fluorinated GHGs with carbon-iodine bond(s)... 1 1
Remaining fluorinated GHGs.................... 2,000 1,800
------------------------------------------------------------------------
* Based on current classification as ``Other fluorinated GHGs.''
** Based on current classification as ``Unsaturated perfluorocarbons
(PFCs), unsaturated HFCs, unsaturated hydrochlorofluorocarbons
(HCFCs), unsaturated halogenated ethers, unsaturated halogenated
esters.''

2. Additional Proposed Revisions To Improve the Quality of Data
Collected for Subpart A
The EPA is proposing several revisions to subpart A to align with
the proposed addition of subparts B (Energy Consumption), WW (Coke
Calciners), XX (Calcium Carbide Production), YY (Caprolactam, Glyoxal,
and Glyoxylic Acid Production), and ZZ (Ceramics Manufacturing), as
described in sections II.B and IV of this preamble. First, we are
proposing to revise 40 CFR 98.2(a)(1) through (3) to clarify that (1)
direct emitters required to report under any source category listed in
Tables A-3 or A-4 to subpart A of part 98 or stationary fuel combustion
sources that meet the requirements of 40 CFR 98.2(a)(3), or required to
resume reporting under Sec. Sec. 98.2(i)(1), (2), or (3); and (2) that
are not eligible to discontinue reporting under the provisions of 40
CFR 98.2(i)(1) through (3), would be required to cover metered
purchased energy consumption (proposed subpart B) in their annual GHG
report. As described in section IV.A of this preamble, direct emitters
subject to part 98 would be required to report the annual quantity of
electricity purchased and the annual quantity of thermal energy
products purchased. Specifically, we are proposing to revise paragraphs
98.2(a)(1) through (3) to add that the annual GHG report must cover
``energy consumption (subpart B of this part)'' for facilities that are
subject to direct emitter subparts. Additionally, we are proposing to
revise the reporting requirements for the annual GHG report in 40 CFR
98.3(c)(4) to add a requirement for facilities to report the annual
quantities of electricity purchased and the annual quantities of
thermal energy products purchased. The proposed requirements ensure
that facilities that report emissions of GHGs include total energy
consumption data with the annual report. Additional information on
proposed subpart B may be found in section IV.A of this preamble.
Similarly, we are proposing to revise Table A-3 and Table A-4 to
part 98 to clarify the reporting applicability for facilities included
in the proposed new source categories described in sections IV.B
through E of this preamble. Currently, a facility included in a source
category listed in Table A-3 to subpart A of part 98 is subject to
reporting under part 98. Source categories in Table A-3 are referred to
as ``all-in'' source categories because reporting applies regardless of
other source category or stationary fuel combustion emissions at the
facility. The EPA's ``all-in'' approach generally applies for
industries for which all facilities are emitters of a similar quantity,
or where the EPA has determined it requires more data on certain
industries to identify the parameters that influence GHG emissions from
the source category. A facility that contains a source category listed
in Table A-4 to subpart A of part 98 must report only if estimated
annual emissions from all applicable source categories in Tables A-3
and Table A-4 of part 98 are 25,000 metric tons carbon dioxide
equivalents (mtCO<INF>2</INF>e) or more. Source categories in Table A-4
are referred to as ``threshold'' source categories. The EPA's
``threshold'' approach generally applies when a source category
contains emitters with a range in emissions quantity and the EPA wants
to collect information from those facilities within the source category
with larger total emissions from multiple process units or collocated
source categories that emit larger levels of GHGs collectively, and not
burden smaller emitters with a reporting obligation.
We are proposing to revise Table A-3 to subpart A of part 98 to
include new source categories for coke calciners (subpart WW), calcium
carbide production (subpart XX), and caprolactam, glyoxal, and
glyoxylic acid production (subpart YY). For coke calciners (subpart
WW), as discussed in section IV.B of this preamble, we are proposing to
include the source category as an ``all-in'' source category in Table
A-3; based on the threshold analysis, most coke calciners are large
emission sources that would be expected to exceed all of the thresholds
considered, with no significant differences in the coverage of
reporting facilities or the total U.S. emissions covered. As described
in section IV.C of this preamble, we determined in a threshold analysis
for the calcium carbide production source category that there is a
single producer of calcium carbide in the United States whose known
emissions would well exceed the 25,000 mtCO<INF>2</INF>e threshold
currently referenced in 40 CFR 98.2(a)(2). Therefore, we are proposing
to require that all facilities report in this source category, which
would capture all U.S. emissions and

[[Page 32870]]

avoid the need for the facility to calculate whether GHG emissions
exceed the threshold value. The threshold analysis for the caprolactam,
glyoxal, and glyoxylic acid production source category, as described in
detail in section IV.D of this preamble, identified and estimated
emissions for six facilities and concluded that setting a threshold of
25,000 mtCO<INF>2</INF>e would cover only half of the identified
facilities but result in only a small difference in the total U.S.
emissions that would be covered. After considering this information, we
are proposing to add the caprolactam, glyoxal, and glyoxylic acid
production source category as an ``all-in'' source category to Table A-
3 to subpart A of part 98 to gather information from all applicable
facilities, in order to account for the uncertainty in the data and
assumptions used in the threshold analysis (see section IV.D.4 of this
preamble for additional information). The proposed revisions to Table
A-3 specify that new subparts WW, XX, and YY would become applicable in
RY2025 (see section V of this preamble for additional details).\28\
---------------------------------------------------------------------------

\28\ The proposed revisions to Table A-3 to subpart A also
include the proposed source category for Geologic Sequestration of
Carbon Dioxide with Enhanced Oil Recovery Using ISO 27916, proposed
as subpart VV of part 98 in the 2022 Data Quality Improvements
Proposal. Under this supplemental proposal, we are now proposing
this rule, if finalized, would be applicable in RY2025.
---------------------------------------------------------------------------

We are proposing to revise Table A-4 to subpart A of part 98 to
include a new source category for ceramics production (subpart ZZ). As
described in sections IV.E of this preamble, we conducted a threshold
analysis for the ceramics production source category and determined the
facilities in this source category have a broader range in emissions
quantity. In order to collect information from those facilities within
the source category with larger total emissions from multiple process
units, or collocated source categories that emit larger levels of GHGs
collectively, we are proposing to assign a threshold of 25,000
mtCO<INF>2</INF>e. For ceramics production (subpart ZZ), we are
proposing that part 98 would apply to certain ceramics production
processes that exceed a minimum production level (i.e., annually
consume at least 2,000 tons of carbonates or 20,000 tons of clay heated
to a temperature sufficient to allow the calcination reaction to occur)
and that exceed the 25,000 mtCO<INF>2</INF>e threshold. The proposed
requirements would ensure coverage of large ceramics production
facilities, while reducing the reporting burden for facilities with
collocated source categories that may have already met GHGRP reporting
thresholds under a different subpart of part 98 but may only have a
small artisan-level ceramics process on site. We are proposing to
revise Table A-4 such that new subpart ZZ would become applicable in
RY2025. See section V of this preamble for additional details on the
anticipated schedule for the proposed amendments.
In keeping with the proposed revisions discussed in section II.A.1
of this preamble, we are proposing minor clarifications to the
reporting and special provisions for best available monitoring methods
in 40 CFR 98.3(k) and (l), which apply to owners or operators of
facilities or suppliers that first become subject to any subpart of
part 98 due to amendment to Table A-1 to subpart A. The current
provisions, which were incorporated in the 2014 Fluorinated Gas Final
Rule, require that these facilities or suppliers must start monitoring
and collecting GHG data in compliance with the applicable subparts of
part 98 to which the facility is subject ``starting on January 1 of the
year after the year during which the change in GWPs is published,'' and
provide for the use of best available monitoring methods, as
applicable, for a period of three months ``of the year after the year
during which the change in GWPs is published.'' Specifically, we are
proposing to revise the term ``published'' to add ``in the Federal
Register as a final rulemaking.'' The proposed changes would clarify
the EPA's intent that the requirements apply to facilities or supplies
that are first subject to the GHGRP in the year after the year the GWP
is published as part of a final rule.
For the reasons described in section II.E of this preamble, the EPA
is proposing amendments to several defined terms in the General
Provisions. First, we are proposing to revise the definition of
``bulk'' to provide clarity to the regulated community. Under 40 CFR
98.6 ``bulk'' is currently defined as ``with respect to industrial GHG
suppliers and CO<INF>2</INF> suppliers, [bulk] means the transfer of a
product inside containers, including, but not limited to tanks,
cylinders, drums, and pressure vessels.'' Importers of industrial GHGs
have had questions regarding this definition, particularly whether
imports of motor vehicle air conditioner charging kits would fall
within this definition given that the gas is in small cans in this
case. The EPA notes that the current definition does not include any
limit or restriction based on the size of the vessel in which the
industrial GHG or CO<INF>2</INF> is transferred. Therefore, we maintain
that the imports of industrial GHGs and CO<INF>2</INF> in small cans,
such as motor vehicle air conditioner charging kits, would be
reportable under subpart OO (Suppliers of Industrial Greenhouse Gases)
based on our current definition of bulk. However, to improve clarity,
the EPA is proposing to revise the definition of bulk to read that
``Bulk, with respect to industrial GHG suppliers and CO<INF>2</INF>
suppliers, means a transfer of gas in any amount that is in a container
for the transportation or storage of that substance such as cylinders,
drums, ISO tanks, and small cans. An industrial gas or CO<INF>2</INF>
that must first be transferred from a container to another container,
vessel, or piece of equipment in order to realize its intended use is a
bulk substance. An industrial GHG or CO<INF>2</INF> that is contained
in a manufactured product such as electrical equipment, appliances,
aerosol cans, or foams is not a bulk substance.''
The revised definition would provide clarity to the regulated
community regarding whether the import or export of gas in small
containers would be considered ``bulk.'' The definition also provides
additional details for suppliers to determine whether different types
of imports or exports would fall within the definition. For example,
this definition makes it clear that imports of motor vehicle air
conditioner charging kits would qualify as imports of bulk substances,
because the gas must first be transferred from a container (i.e., the
kit) to another container, vessel, or piece of equipment (i.e., the
motor vehicle) in order to realize its intended use (i.e., comfort
cooling). In addition, the revised definition makes it clear that gas
contained in pre-charged equipment, appliances, foams, or aerosol cans
would not qualify as bulk substances. This is consistent with the EPA's
consideration of bulk in the past. In response to comments on the 2009
Final Rule (see ``Mandatory Greenhouse Gas Reporting Rule: EPA's
Response to Public Comments Volume No.: 40 Subpart OO--Suppliers of
Industrial Greenhouse Gases, September 2009''), we stated that the
``term `bulk' is intended to distinguish imports and exports in
containers (cylinders, drums, etc.) from imports and exports in
products; it is not intended to establish a minimum container or
shipment size below which reporting would not be required.'' After
considering comments, the EPA did include provisions in the industrial
gas supply reporting requirements (40 CFR 98.416) that exempt small
shipments (those including less than 25 kilograms) from the import and
export reporting requirements. However, a minimum

[[Page 32871]]

shipment size does not imply a minimum container size.
Finally, the revised definition would align the definition of
``bulk'' for industrial GHGs and CO<INF>2</INF> under the GHG Reporting
Rule (40 CFR part 98) with the definition of ``bulk'' under the
regulations to phasedown hydrofluorocarbons (40 CFR part 84). We
recognize that some importers and exporters of industrial gases would
be covered under both programs, and that a consistent definition would
promote efficiency and clarity for implementation of both programs. For
example, we anticipate that importers and exporters may use the data
entered in the EPA's HFC and ODS Allowance Tracking (HAWK) system to
generate draft reporting forms that could be reviewed and submitted to
the EPA's e-GGRT annual reporting system under subpart OO of 40 CFR
part 98. A consistent set of definitions between the two programs would
simplify reporting. Relatedly, we seek comment on whether this
definition of bulk would be useful for suppliers of carbon dioxide
(subpart PP of part 98).
Next, the EPA is proposing to revise the definition of ``greenhouse
gas or GHG'' to clarify the treatment of fluorinated greenhouse gases.
The definition of ``greenhouse gas or GHG'' currently includes both a
reference to the definition of ``fluorinated greenhouse gas'' and a
partial list of the fluorinated GHGs that are encompassed by the
definition of ``fluorinated greenhouse gas.'' To simplify and clarify
the definition of ``greenhouse gas or GHG,'' we are proposing to remove
the partial list of fluorinated GHGs currently included in the
definition and to simply refer to the definition of ``fluorinated
greenhouse gas (GHGs).'' We are also proposing to explicitly include
the acronym ``(GHGs)'' after the term ``fluorinated greenhouse gas''
both in the definition of ``greenhouse gas or GHG'' and in the
definition of ``fluorinated greenhouse gas.'' This change would not
affect the scope of substances that are considered GHGs under part 98
but would avoid redundancy and potential confusion between the
definitions of ``greenhouse gas'' and ``fluorinated greenhouse gas.''
With this revision, the definition of ``Greenhouse gas or GHG'' would
read: ``Greenhouse gas or GHG means carbon dioxide (CO<INF>2</INF>),
methane (CH<INF>4</INF>), nitrous oxide (N<INF>2</INF>O), and
fluorinated greenhouse gases (GHGs) as defined in this section.''
Consistent with our proposed revisions of the fluorinated GHG
groups used to assign default GWPs, discussed in section III.A.1 of
this preamble, the EPA is also proposing to add seven definitions and
to revise two definitions of fluorinated GHG groups or of compound
types or molecular structures within those groups. Specifically, we are
proposing to add definitions of ``unsaturated chlorofluorocarbons
(CFCs),'' ``saturated chlorofluorocarbons (CFCs),'' ``unsaturated
bromofluorocarbons (BFCs),'' ``unsaturated bromochlorofluorocarbons
(BCFCs),'' ``unsaturated hydrobromofluorocarbons (HBFCs),'' and
``unsaturated hydrobromochlorofluorocarbons (HBCFCs).'' In addition, we
are proposing to add a definition of ``cyclic'' as it applies to
molecular structures of various fluorinated GHGs. We are also proposing
to revise the definition of ``fluorinated greenhouse (GHG) group'' to
include the new and revised groups.
We are also proposing to revise the term ``other fluorinated
GHGs,'' which is the name of the last of the twelve fluorinated GHG
groups that are used to assign default GWPs to compounds that do not
have chemical-specific GWPs in Table A-1 to subpart A of part 98. The
term ``other fluorinated GHGs'' is intended to encompass fluorinated
GHGs that are not included in any of the first eleven fluorinated GHG
groups that are specified based on their molecular compositions and
structures. However, the phrase ``other fluorinated GHGs'' is also used
in other contexts in part 98, potentially leading to confusion. For
example, the phrase ``other fluorinated GHGs'' occurs but is not
intended to mean the twelfth fluorinated GHG group in subpart L of part
98 (Fluorinated Gas Production) at 40 CFR 98.122(d), 98.124(g)(1)(iv),
98.124(g)(4), and 98.126(a)(4)(ii). We are therefore proposing to
revise the term ``other fluorinated GHGs'' to ``remaining fluorinated
GHGs'' to avoid such confusion.\29\ In addition, we are proposing to
revise the definition of the term to reflect the new and revised
fluorinated GHG groups discussed in section III.A.1 of this preamble.
---------------------------------------------------------------------------

\29\ As discussed in section II.A.1 of this preamble regarding
the update of global warming potentials, we are proposing to add two
new fluorinated GHG groups in this notification. If these two new
fluorinated GHG groups are added and the term ``other fluorinated
GHGs'' is revised to ``remaining fluorinated GHGs'' in the final
rule, then the group ``remaining fluorinated GHGs'' would become the
fourteenth fluorinated GHG group.
---------------------------------------------------------------------------

We are proposing to revise the definition of ``fluorinated heat
transfer fluids'' and to move it from 40 CFR 98.98 to 40 CFR 98.6 to
harmonize with proposed changes to subpart OO of part 98 (Suppliers of
Industrial Greenhouse Gases), as discussed in section III.K of this
preamble. Fluorinated compounds used as F-HTFs include, but are not
limited to, perfluoropolyethers (including PFPMIE),
perfluoroalkylamines, perfluoroalkylmorpholines, perfluoroalkanes,
perfluoroethers, perfluorocyclic ethers, and hydrofluoroethers. Many of
these compounds have GWPs near 10,000 and atmospheric lifetimes near
1,000 years. Currently, the term ``fluorinated heat transfer fluids''
is defined under subpart I of part 98 (Electronics Manufacturing) in
the context of electronics manufacturing, but we have become aware of
uses of F-HTFs that are chemically similar to those listed above in
industries other than electronics. For this reason, we are proposing to
require suppliers of F-HTFs that report under subpart OO to identify
the end uses for which the heat transfer fluid is used and the
aggregated annual quantities of each F-HTF transferred to each end use.
To clarify that the supplier reporting requirement would apply to F-
HTFs that are used outside of the electronics industry, we are
proposing to move the definition of ``fluorinated heat transfer
fluids'' to subpart A and to revise the definition (1) to explicitly
include industries other than electronics manufacturing, and (2) to
exclude most hydrofluorocarbons (HFCs), which are widely used as heat
transfer fluids outside of electronics manufacturing (in household,
mobile, commercial, and industrial air conditioning and refrigeration)
and are regulated under the American Innovation and Manufacturing Act
of 2020 (AIM) regulations at 40 CFR part 84.\30\ Including all HFCs in
the definition of ``fluorinated heat transfer fluids'' would expand the
definition, and the associated reporting requirements, far beyond our
intent, which is to gather information on supplies and end uses of F-
HTFs used in electronics manufacturing and in similar specialized
applications. The one HFC that would remain in the definition is HFC-
43-10mee, which is used as an F-HTF in electronics manufacturing and
which, like most other F-HTFs used in electronics manufacturing (and
unlike most HFCs used as refrigerants), is a liquid at room temperature
and pressure. With these changes, the proposed definition of
``fluorinated heat transfer fluids'' would read:
---------------------------------------------------------------------------

\30\ Hydrofluorocarbons would continue to be considered
``fluorinated greenhouse gases'' and therefore reportable under
other provisions of part 98.

Fluorinated heat transfer fluids means fluorinated GHGs used for
temperature control, device testing, cleaning substrate surfaces and
other parts, other solvent

[[Page 32872]]

applications, and soldering in certain types of electronics
manufacturing production processes and in other industries.
Fluorinated heat transfer fluids do not include fluorinated GHGs
used as lubricants or surfactants in electronics manufacturing. For
fluorinated heat transfer fluids, the lower vapor pressure limit of
1 mm Hg in absolute at 25 [deg]C in the definition of ``fluorinated
greenhouse gas'' in Sec. 98.6 shall not apply. Fluorinated heat
transfer fluids include, but are not limited to, perfluoropolyethers
(including PFPMIE), perfluoroalkylamines, perfluoroalkylmorpholines,
perfluoroalkanes, perfluoroethers, perfluorocyclic ethers, and
hydrofluoroethers. Fluorinated heat transfer fluids include HFC-43-
---------------------------------------------------------------------------
10meee but do not include other hydrofluorocarbons.

We request comment on the proposed definition. We also request
comment on other options to avoid requiring suppliers to report uses of
HFCs (and potentially other F-GHGs) used in most air-conditioning and
refrigeration applications, including the option of revising the
definition to explicitly include only fluorinated GHGs that are liquid
at room temperature (e.g., that have boiling points below 27 degrees C
[about 81 degrees F] at one atmosphere, which is a few degrees below
the boiling point of the F-GHG with the lowest boiling point that is
marketed for use as an HTF, 3M\TM\ Fluorinert\TM\ FC-87.).
In addition, the EPA is proposing to update 40 CFR 98.7 What
standardized methods are incorporated by reference into this part? To
reflect harmonizing changes based on the proposed addition of subparts
B (Energy Consumption), WW (Coke Calciners), and XX (Calcium Carbide
Production) to part 98, as well as the proposed revisions to subpart Y
of part 98 (Petroleum Refineries). The proposed revisions surrounding
these subparts include test methods. Specifically, the proposed
revisions to subparts B and XX add one test method to 40 CFR 98.24(b),
and two test methods to 40 CFR 98.504(b), respectively. The proposed
revisions to remove coke calciners from subpart Y and add them to new
subpart WW require not only the removal of monitoring requirements and
associated test methods for coke calciners from subpart Y, but also
reflect the latest versions of those test methods.
As described in section IV.A of this preamble, under newly proposed
subpart B, facilities would need to develop a written Metered Energy
Monitoring Plan (MEMP). In that MEMP, facilities would be required to
specify recordkeeping activities for electric meters, including an
indication of whether the meter conforms to American National Standards
Institute (ANSI) standard C12.1-2022 Electric Meters--Code for
Electricity Metering or another, similar consensus standard with
accuracy specifications at least as stringent as one of the cited ANSI
standards. We are proposing to incorporate by reference this ANSI test
method as indicated in 40 CFR 98.24(b) and 40 CFR 98.7(a).
Per section IV.C of this preamble, calcium carbide production
facilities would be required to analyze carbon content at least
annually using standard ASTM methods that are currently used in similar
source categories under part 98, including the American Society for
Testing and Materials (ASTM) D5373-08 Standard Test Methods for
Instrumental Determination of Carbon, Hydrogen, and Nitrogen in
Laboratory Samples of Coal or ASTM C25-06, Standard Test Methods for
Chemical Analysis of Limestone, Quicklime, and Hydrated Lime. We are
proposing to revise paragraphs 40 CFR 98.7(e)(1) and (27) to add a
reference to proposed 40 CFR 98.504(b) to clarify these methods are
incorporated by reference for the calcium carbide production source
category.
As described in section III.H of this preamble, the EPA is
proposing to remove coke calciners from subpart Y. Instead of reporting
coke calcining unit emissions under subpart Y, facilities with coke
calciners are proposed to report those emissions in the new proposed
subpart WW. Subpart Y at 40 CFR 98.254(h) currently requires the
determination of the mass of petroleum coke using Specifications,
Tolerances, and Other Technical Requirements For Weighing and Measuring
Devices, National Institute of Standards and Technology (NIST) Handbook
44 (2009) and the calibration of the measurement device according to
the procedures specified the same handbook. Those requirements are
proposed to be removed from subpart Y and the updated version,
Specifications, Tolerances, and Other Technical Requirements For
Weighing and Measuring Devices, NIST Handbook 44 (2022), is proposed
for subpart WW. These changes are reflected in subparts A, Y, and WW.
Likewise, three methods used to help determine the carbon content of
petroleum coke are proposed to be removed from subpart Y (40 CFR
98.254(i)) and updated versions of those same methods are proposed for
new subpart WW. Those methods are (1) ASTM D3176-15 Standard Practice
for Ultimate Analysis of Coal and Coke, (2) ASTM D5291-16 Standard Test
Methods for Instrumental Determination of Carbon, Hydrogen, and
Nitrogen in Petroleum Products and Lubricants, and (3) ASTM D5373-21
Standard Test Methods for Determination of Carbon, Hydrogen, and
Nitrogen in Analysis Samples of Coal and Carbon in Analysis Samples of
Coal and Coke.
In the 2022 Data Quality Improvements Proposal, we proposed to add
subpart VV to part 98 (Geologic Sequestration of Carbon Dioxide With
Enhanced Oil Recovery Using ISO 27916). It is likely that many
reporters that would be subject to the new proposed subpart VV would
have previously been subject to subpart UU of part 98 (Injection of
Carbon Dioxide). We received comments saying that the applicability of
proposed subpart VV was unclear. Therefore, as described in sections
III.O and III.P of this preamble, the EPA is now proposing to revise
section 98.470 of subpart UU of part 98 and sections 98.480 and 98.481
of proposed subpart VV to clarify the applicability of each subpart
when a facility chooses to quantify their geologic sequestration of
CO<INF>2</INF> in association with EOR operations through the use of
the CSA/ANSI ISO 27916:2019 method. The proposed changes also would
clarify how CO<INF>2</INF>-EOR projects that may transition to use of
the CSA/ANSI ISO 27916:2019 method during a reporting year would be
required to report for the portion of the reporting year before they
began using CSA/ANSI ISO 27916:2019 (under subpart UU) and for the
portion after they began using CSA/ANSI ISO 27916:2019 (under proposed
subpart VV). Additionally, we previously proposed to incorporate by
reference the CSA/ANSI ISO 27916:2019 test method in the 2022 Data
Quality Improvements Proposal. In light of these supplemental proposed
revisions, we are proposing to modify the proposed incorporation by
reference regulatory text at 40 CFR 98.7(g) consistent with these
proposed revisions, such that the regulatory text would also reference
paragraphs 40 CFR 98.470(c) and 98.481(c).

B. Subpart C--General Stationary Fuel Combustion

For the reasons described in section II.D of this preamble, we are
proposing to add requirements for facilities under subpart C of part 98
(General Stationary Fuel Combustion) to report whether the unit is an
electricity generating unit (EGU) for each configuration that reports
emissions under either the individual unit provisions at 40 CFR
98.36(b) or the multi-unit provisions at 40 CFR 98.36(c). Additionally,
for multi-unit reporting configurations, we are proposing to add
requirements for facilities to report an estimated decimal fraction of
total emissions from the group that are attributable to EGU(s) included
in the group.

[[Page 32873]]

Under the current subpart C reporting requirements, the EPA cannot
determine the quantity of EGU emissions included in the reported total
emissions for the subpart. The proposed changes would allow the EPA to
estimate the EGU emissions included in the subpart C emission totals.
Understanding subpart C EGU GHG emissions is important to ensure more
accurate data analysis, to understand attribution of GHG emissions to
the power plant sector, and to inform policy goals under the CAA. For
example, the EPA's current data publication products attribute subpart
C emissions to the power plant sector based on the reported NAICS code
for the facility. However, some manufacturing facilities, such as
petroleum refineries and pulp and paper manufacturers, operate
stationary combustion sources that generate electricity. Reporting of
an EGU indicator for these units would allow the EPA to assign the
emissions from any electricity generating units at the facility more
appropriately to the power plant sector. Similarly, data analyses,
including those used for policy development, would be able to use the
EGU indicator to ensure a more comprehensive EGU data set was used.
We do not anticipate that the proposed data elements would require
any additional monitoring or data collection by reporters, because the
only added data elements would be whether any subpart C unit(s)
included in the report are EGU(s), and, for multi-unit configurations,
an estimated fraction of total emissions from the group that are
attributable to EGU(s) included in the group. I proposed changes would
result in minimal additional burden to reporters because the reporter
knows if the unit is an EGU and, if so, the estimated fraction of total
emissions attributable to the EGU can be determined by engineering
estimates. We are also proposing related confidentiality determinations
for the additional data elements, as discussed in section VI of this
preamble.

C. Subpart F--Aluminum Production

For the reasons described in section II.D of this preamble, we are
proposing to revise the reporting requirements of subpart F of part 98
(Aluminum Production). We are proposing to revise the reporting
requirements at 40 CFR 98.66(a) and (g) to require that facilities
report the facility's annual production capacity and annual days of
operation for each potline. The capacity of the facility and capacity
utilization would provide useful information for understanding
variations in annual emissions, to understand trends across the sector
and to support analysis of this source. We often contact facilities
seeking to understand yearly variations in the facility emissions, and
facilities explain that the variation was due to a smelter not
operating for a particular time period. Currently it is difficult to
determine without correspondence with the facility whether variations
in emissions are due to changes in yearly production or efforts to
improve operations to decrease emissions. If data on the production
capacity and annual days of operation for each potline are included in
the annual report, it could explain the variation and eliminate the
need for correspondence with facilities. We are also proposing related
confidentiality determinations for the additional data elements, as
discussed in section VI of this preamble.

D. Subpart G--Ammonia Manufacturing

For the reasons described in section II.D of this preamble, we are
proposing a revision to the reporting requirements of subpart G of part
98 (Ammonia Manufacturing) to enhance the quality and accuracy of the
data collected under the GHGRP. As discussed in section III.G of this
preamble, to increase the GHGRP's coverage of facilities in the
hydrogen production sector we are proposing to amend the applicability
of subpart P (Hydrogen Production) to include all facilities that
produce hydrogen gas as a product regardless of whether the product is
sold, with exemptions for any process unit for which emissions are
reported under another subpart of part 98, including ammonia production
units that report emissions under subpart G. However, we are proposing
to amend subpart G in this action to include a reporting requirement
for facilities to report the annual quantity of excess hydrogen
produced that is not consumed through the production of ammonia. This
change would ensure that revisions to subpart P to exclude reporting
from facilities that are subject to subpart G would not result in the
exclusion of reporting of any excess hydrogen production at facilities
that are subject to subpart G from the GHGRP. The proposed revision
would also help the EPA to understand facilities that engage in captive
hydrogen production and better inform our knowledge of industry
emissions and trends. We are also proposing related confidentiality
determinations for the additional data element, as discussed in section
VI of this preamble.

E. Subpart I--Electronics Manufacturing

We are clarifying a proposed revision to Table I-16 to subpart I of
part 98 (Electronics Manufacturing) to correct a typographical error in
the 2022 Data Quality Improvements Proposal. The June 21, 2022 proposed
rule's amendatory text shows the current DRE for NF<INF>3</INF> of 88
percent instead of the DRE proposed of 96 percent. The DRE calculated
for NF<INF>3</INF> is 96 percent based on data submitted to the EPA, as
shown in the supplemental material ``combined DRE data sets.xlsx'' in
the docket for the proposed rule. For more information on the how the
DREs were calculated, see the preamble to the 2022 Data Quality
Improvements Proposal and the memorandum, Revised Technical Support for
Revisions to Subpart I: Electronics Manufacturing, available in the
docket for this rulemaking, Docket Id. No. EPA-HQ-OAR-2019-0424.
We are also proposing revisions to Table I-18 to subpart I of part
98 to correct the proposed gamma factors to estimate by-products for
NF<INF>3</INF> used in remote plasma cleaning for facilities
manufacturing both wafers <= to 200 mm and 300 mm or greater. The by-
product gamma for CHF<INF>3</INF>, CH<INF>2</INF>F<INF>2</INF> and
CH<INF>3</INF>F for facilities manufacturing both wafer sizes should be
equal to the by-product gamma factor for 300 mm and not an average of
the 200 mm gamma (which is zero) and the 300 mm gamma. More information
can be found in the revised technical support document (TSD), Revised
Technical Support for Revisions to Subpart I: Electronics
Manufacturing, available in the docket for this rulemaking (Docket Id.
No. EPA-HQ-OAR-2019-0424).

F. Subpart N--Glass Production

For the reasons described in section II.D of this preamble, we are
proposing revisions to the recordkeeping and reporting requirements of
subpart N of part 98 (Glass Production) to enhance the quality and
accuracy of the data collected under the GHGRP. We are proposing to
revise the existing reporting and recordkeeping requirements for both
CEMS and non-CEMS facilities to require that they report and maintain
records of recycled scrap glass (cullet) used as a raw material.
Specifically, we are proposing to add provisions to 40 CFR 98.146 to
require reporting of the annual quantity of cullet used (in tons) in
each continuous glass melting furnace and in all furnaces combined by
glass type (e.g., container, flat glass, fiber glass, or specialty
glass). This quantity would include both recycled glass that was
brought in from other facilities or purchased from external sources
(e.g., recycling programs) and glass that has been produced at the
facility and then added back into the production process (sometimes
referred to as ``run-

[[Page 32874]]

around''). We are also proposing to add provisions to 40 CFR 98.147 to
require recordkeeping of the monthly quantity of cullet used (in tons)
in each continuous glass melting furnace by product type (e.g.,
container, flat glass, fiber glass, or specialty glass), and the number
of times in the reporting year that missing data procedures were used
to measure monthly quantities of cullet used.
Although there are variations in the types of carbonates used at
different facilities and some facilities use other carbonate raw
materials in much smaller quantities, the major raw materials (i.e.,
fluxes and stabilizers) that emit process-related CO<INF>2</INF>
emissions in glass production are limestone, dolomite, and soda ash. In
general, the composition profile of raw materials is relatively
consistent among individual glass types, however, some facilities use
cullet in their production process. Unlike carbonate-based raw
materials, cullet does not produce process GHG emissions when used in
the glass production process. Therefore, differences in the quantities
of cullet used can lead to variations in emissions from the production
of different glass types. Furthermore, the production of some glass
types (e.g., container, flat glass, fiber glass, specialty glass)
consumes more cullet than others. The amount of cullet used at
individual facilities can also vary from year to year, which can cause
related changes in emissions. Additionally, due to its lower melting
temperature, mixing cullet with other raw materials can reduce the
amount of energy required to produce glass and thus also reduce
combustion emissions related to glass production.
The annual quantities of cullet used would provide a useful metric
for understanding variations and differences in emissions estimates
that may not be apparent in the existing data collected, improve our
understanding of industry trends, and improve verification for the
GHGRP. The proposed data elements would also provide useful information
to improve analysis of this sector in the Inventory. As noted in the
2019 Inventory report,\31\ the EPA reviews the GHGRP data during the
development of inventory estimates for this sector to help understand
the completeness of emission estimates and for quality control.
Including cullet use would increase the transparency and accuracy of
the data set produced by the Inventory. Additionally, collecting more
detailed data on raw materials would improve analysis of this sector by
other EPA programs.
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\31\ See Inventory of U.S. Greenhouse Gas Emissions and Sinks:
1990-2017 (2019), available at <a href="http://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2017">www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2017</a>.
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While we are proposing to collect the sum of both externally-
sourced recycled glass and facility ``run-around'' recycled glass, we
seek comment on the degree to which each of these types of recycled
glass are tracked by facilities, and/or what kinds of cullet use data
are readily available. Furthermore, we seek comment on the degree to
which recycled glass use is tracked by produced glass type, and whether
it is common for a glass melting furnace to be used to produce more
than one glass type in a reporting year. We do not anticipate that the
proposed data elements would require any additional monitoring or data
collection by reporters, as cullet use data are likely available in
existing company records. The proposed changes would therefore result
in minimal additional burden to reporters. We are also proposing
related confidentiality determinations for the additional data
elements, as discussed in section VI of this preamble.

G. Subpart P--Hydrogen Production

The EPA is proposing several amendments to subpart P of part 98
(Hydrogen Production) that include expanding the source category to
include non-merchant hydrogen production facilities, as well as
clarifications and additions to the reporting elements resulting in
enhanced unit-level reporting for facilities in the hydrogen production
sector. As discussed in sections II.B and II.D of this preamble, these
amendments would address potential gaps in applicability and reporting,
allowing the EPA to better understand and track facilities and
emissions. These data would inform future policy considerations under
the CAA, and additionally could inform future policy considerations
like those set forth by other Government programs.
Currently, section 98.160 states, ``A hydrogen production source
category consists of facilities that produce hydrogen gas sold as a
product to other entities.'' This provision notably limits
applicability to so-called ``merchant'' plants that sell hydrogen
produced as a product. Based on requirements in subpart Y of part 98
(Petroleum Refineries), hydrogen production units at petroleum
refineries are required to report hydrogen production GHG emissions
under subpart P even though they do not sell the hydrogen gas to other
entities. Similarly, subpart G of part 98 (Ammonia Manufacturing)
essentially provides calculation methodologies analogous to subpart P
to account for GHG emissions from ammonia production, which entails the
use of captive hydrogen production. However, through external analysis
and communications with facilities reporting to the GHGRP, we
understand that there are other facilities that produce hydrogen and
consume it onsite (i.e., captive plants), that are not required to
report their hydrogen production GHG emissions under subpart P or any
other GHGRP subpart. To increase the GHGRP's coverage of facilities in
the hydrogen production sector, we are proposing to amend the source
category definition in 40 CFR 98.160 to include all facilities that
produce hydrogen gas as a product regardless of whether the product is
sold. We are also proposing to categorically exempt any process unit
for which emissions are reported under another subpart of part 98. This
includes, but is not necessarily limited to, ammonia production units
that report emissions under subpart G of part 98, catalytic reforming
units located at petroleum refineries that produce hydrogen as a by-
product for which emissions are reported under subpart Y of part 98,
and petrochemical production units that report emissions under subpart
X of part 98 (Petrochemical Production). We are also proposing to
exempt process units that only separate out diatomic hydrogen from a
gaseous mixture and are not associated with a unit that produces
diatomic hydrogen created by transformation of one or more feedstocks,
which would codify the existing interpretation currently included in
FAQ #695.\32\ We note that the EPA is also proposing to amend subpart G
of part 98 in this action to include a reporting requirement for
facilities to report the annual quantity of excess hydrogen produced
that is not consumed through the production of ammonia (see section
III.C of the preamble for additional details).
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\32\ See GHGRP FAQ #695 ``What is a hydrogen production process
unit?'' Available at: <a href="https://ccdsupport.com/confluence/pages/viewpage.action?pageId=173080687">https://ccdsupport.com/confluence/pages/viewpage.action?pageId=173080687</a>.
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Additionally, the EPA is proposing to amend the source category
definition to clarify that stationary combustion sources that are part
of the hydrogen production unit (e.g., the reforming furnace and
hydrogen production process unit heater) are part of the hydrogen
production source category and that their emissions are to be reported
under subpart P. Depending on the configuration of the hydrogen
production unit, the exhaust gases from

[[Page 32875]]

the combustion of fuel used to raise the temperature of the feedstocks
and supply energy needed for the transformation reaction may be emitted
through the same stack as the ``process'' emissions (i.e.,
CO<INF>2</INF> produced from the transformation of feedstocks) or
through separate stacks. Currently, 40 CFR 98.162 requires reporting of
GHG emissions ``from each hydrogen production process unit'' under
subpart P and reporting of GHG emissions from ``each stationary
combustion unit other than hydrogen production process units'' under
subpart C of part 98 (General Stationary Fuel Combustion Sources). This
has led to some confusion regarding whether hydrogen production unit
furnaces or process heaters that exhaust through a separate stack than
the process emissions should be reported under subpart P or subpart C
of this part. This proposed amendment to the source category definition
seeks to clarify that these furnaces or process heaters are part of the
hydrogen production process unit regardless of where the emissions are
exhausted. We are also proposing to clarify that, if a hydrogen
production unit with separate stacks for ``process'' emissions and
``combustion'' emission uses a CEMS for the process emissions stack,
reporters must calculate and report the CO<INF>2</INF> emissions from
the hydrogen production unit's fuel combustion using the mass balance
equations in subpart P (equations P-1 through P-3) in addition to the
CO<INF>2</INF> emissions measured by the CEMS. Although this
circumstance is expected to be rare, these amendments are necessary to
clarify the reporting requirements for cases where hydrogen production
process and combustion emissions are emitted through separate stacks.
These amendments also allow for a more direct comparison of the GHG
emission intensities for hydrogen production units using single versus
dual stack configurations.
Hydrogen production can be achieved through a variety of chemical
processes including the use of steam methane reforming (SMR), SMR
followed by water gas shift (WGS) reaction, partial oxidation (POX),
POX followed by WGS, and water or brine electrolysis. Each chemical
production process has different yields of hydrogen and, depending on
the desired product, the product stream may require purification. There
are different purification processes that most commonly include
pressure swing adsorption (PSA), amine adsorption, or membrane
separation. Similar to the chemical production process, each
purification process may yield products of different hydrogen purity
and have different energy requirements. It is also worth noting that
some hydrogen plants may perform purification of hydrogen that is
included in the feedstock entering the plant. An example would be a
refinery that directs the exhaust gas from a process unit that has
elevated levels of hydrogen to its hydrogen plant. In this case, the
hydrogen plant acts to both ``produce hydrogen'' (by reforming,
gasification, oxidation, reaction, or other feedstock transformations)
and ``purify hydrogen'' that exists in the feedstock to the plant. That
is, the total quantity of hydrogen exiting the hydrogen plant may
consist of hydrogen chemically produced (and subsequently purified)
within the unit as well as hydrogen merely purified by the unit.
For the reasons described in section II.D of this preamble, in
order to best understand the reported data, we are proposing to add
requirements for facilities to the report the process type for each
hydrogen production unit (i.e., SMR, SMR-WGS, POX, POX-WGS, Water
Electrolysis, Brine Electrolysis, or Other (specify)), the purification
type for each hydrogen production unit (i.e., PSA, Amine Adsorption,
Membrane Separation, Other (specify), or none), and the annual quantity
of hydrogen that is only purified by each hydrogen production unit. We
note that subpart P currently requires reporting of the quantity of
hydrogen that is produced by each hydrogen production unit. We intended
this quantity to only include that quantity of hydrogen produced in the
unit by reforming, gasification, oxidation, reaction, or other
transformations of feedstocks. Through verification efforts, we
identified some facilities that were reporting the total quantity of
hydrogen exiting the hydrogen production unit, not just the quantity of
hydrogen produced within the unit via reforming, gasification,
oxidation, reaction, or other transformations of feedstocks. We could
identify these facilities because the ratio of hydrogen produced to
feedstock consumed was outside of the expected range. We developed and
posted a frequently asked question (FAQ #698) \33\ to clarify this
reporting element, but some reporters may still be reporting their
combined quantity of hydrogen produced plus the quantity of hydrogen
merely purified. In addition to proposing to add the annual quantity of
hydrogen that is only purified by each hydrogen production unit, we are
also proposing to clarify that the current reporting requirement is the
annual quantity of hydrogen that is produced ``. . . by reforming,
gasification, oxidation, reaction, or other transformations of
feedstocks.''
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\33\ See GHGRP FAQ #698 ``How do I determine the quantity of
hydrogen produced?'' Available at: <a href="https://ccdsupport.com/confluence/pages/viewpage.action?pageId=173080692">https://ccdsupport.com/confluence/pages/viewpage.action?pageId=173080692</a>.
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We are also proposing to amend the current reporting requirement in
40 CFR 98.166(c) regarding the facility-level quantity of
CO<INF>2</INF> that is collected and transferred offsite to require the
quantity of CO<INF>2</INF> collected and transferred offsite to be
reported on a unit-level. This is consistent with other revisions
proposed in subpart P in the 2022 Data Quality Improvements Proposal
(e.g., mass of non-CO<INF>2</INF> carbon (excluding methanol) collected
and transferred offsite) and would allow the EPA to perform unit-level
analyses. We are also proposing to require reporting of the annual net
quantity of steam consumed by the unit, which would be a positive
quantity if the hydrogen production unit is a net steam user (i.e.,
uses more steam than it produces) and a negative quantity if the
hydrogen production unit is a net steam producer (i.e., produces more
steam than it uses). Together, these proposed additional, amended, and
clarified reporting requirements would enable us to perform
benchmarking across process types at the unit-level, conduct more
rigorous verification of the reported data, better understand
production quantities, and collect more comprehensive and accurate data
to inform future policy decisions.
Because we are proposing to require all data elements be reported
at the unit level, we are also proposing to reorganize and consolidate
all of the reporting elements reported at the unit level under 40 CFR
98.166(b) regardless of the calculation method (i.e., mass balance or
CEMS). We are also proposing reporters provide the emissions
calculation method used (CEMS for single hydrogen production unit; CEMS
on a common stack for multiple hydrogen production units; CEMS on a
common stack with hydrogen production unit(s) and other sources; CEMS
measuring process emissions alone plus mass balance for hydrogen
production unit fuel combustion using equations P-1 through P-3; mass
balance using equations P-1 through P-3 only; mass balance using
equations P-1 through P-4). If a common stack CEMS is used, either for
multiple hydrogen production units or that includes emissions from
other sources, we are proposing to require that the estimated fraction
of CO<INF>2</INF> emissions attributable to each hydrogen production
unit be reported so

[[Page 32876]]

we can estimate unit-level CO<INF>2</INF> emissions for each hydrogen
production unit. The revisions in 40 CFR 98.166(b) also require a
proposed revision to 40 CFR 98.167(b) to broaden the recordkeeping
requirements related to elements reported under 40 CFR 98.166(b).
We are also proposing to remove and reserve the recordkeeping
requirements in 40 CFR 98.167(c). We determined that these
recordkeeping requirements at 40 CFR 98.167(c)(1) are redundant to the
general requirements already specified in 40 CFR 98.3(g) and that the
requirements at 40 CFR 98.167(c)(2) and (3) are not applicable to
hydrogen production units using the calculation method in 40 CFR
98.163(b).
We anticipate that the proposed data elements would require some
additional monitoring or data collection by reporters. First, we are
proposing to add several reporting elements to better characterize the
type of hydrogen production unit and the type of associated
purification process used. This information is readily available by
hydrogen production unit owners or operators, so the data collection
effort would be minimal and would not require any additional
monitoring. We are also proposing to require reporting of emission and
activity on a process unit basis, some of which was previously required
only at the facility level. For reporters with multiple hydrogen
production units, this may lead to a slight increase in the data
collected by reporters. Finally, by proposing to broaden the source
category to include captive hydrogen production units, there may be new
reporters under subpart P. We expect that the number of new reporters
would be small, because captive hydrogen production units at petroleum
refineries were already required to report under subpart P due to
requirements in subpart Y. However, there may be additional captive
hydrogen production units that would newly have to report under subpart
P and these reporters would have additional monitoring or data
collection requirements. The proposed changes would therefore result in
minimal additional burden to current subpart P reporters and more
substantive additional burden to new reporters to subpart P. We are
also proposing related confidentiality determinations for the
additional data elements, as discussed in section VI of this preamble.
Due to the expected importance of hydrogen in future energy supply,
the EPA is considering additional revisions to subpart P. The first
revision would be to make subpart P an ``all-in'' subpart, such that
any facility meeting the definition of the hydrogen production source
category at 40 CFR 98.160 would be required to report under the GHGRP.
This would entail moving subpart P from Table A-4 to Table A-3 so that
it would no longer be subject to the 25,000 mtCO<INF>2</INF>e
applicability threshold at 40 CFR 98.2(a)(2). The purpose of this
potential revision would be to collect information on hydrogen
production facilities that use electrolysis or other production methods
that may have small direct emissions but use relatively large
quantities of offsite energy to power the process. So, although the
emissions occurring onsite at these hydrogen production facilities may
fall below the current applicability threshold, the combined direct
emissions (i.e., ``scope 1'' emissions) and emissions attributable to
energy consumption (i.e., ``scope 2'' emissions) \34\ could be
significant. These considerations are especially important in
understanding hydrogen as a fuel source. The EPA is aware of two
concerns with this potential revision. First, it may be burdensome to
small hydrogen producers. Second, even if small producers were
exempted, the remaining newly applicable facilities (i.e., those that
have small direct emissions but use large quantities of offsite energy)
may be eligible to cease reporting after three to five years, resulting
in a limited data set.
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\34\ See section IV.A.1 of this preamble for additional
information on the EPA's collection of data related to energy
consumption.
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