[Federal Register Volume 89, Number 168 (Thursday, August 29, 2024)]
[Notices]
[Pages 70177-70181]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-19403]
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ENVIRONMENTAL PROTECTION AGENCY
[EPA-HQ-OAR-2024-0350; FRL 12138-01-OAR]
Use of Advanced and Emerging Technologies for Quantification of
Annual Facility Methane Emissions Under the Greenhouse Gas Reporting
Program
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice; request for information (RFI).
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[[Page 70178]]
SUMMARY: The EPA invites public comment on the potential for expanded
use of advanced and emerging technologies for methane emissions
quantification in EPA's Greenhouse Gas Reporting Program (GHGRP). These
technologies are an important part of EPA's GHGRP, including under the
recently finalized amendments for Petroleum and Natural Gas Systems.
EPA intends to use the feedback received in response to this RFI to
consider whether it is appropriate to undertake further rulemaking
addressing the use of advanced measurement technologies in the GHGRP
for petroleum and natural gas systems and municipal solid waste (MSW)
landfills, beyond the current role provided in existing rules for these
technologies.
DATES: Comments must be received on or before October 28, 2024.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2024-0350, to the Federal Portal: https://www.regulations.gov.
Follow online instructions for submitting comments. Once submitted,
comments cannot be edited or withdrawn. Do not submit electronically
any information you consider to be Confidential Business Information
(CBI). EPA may publish any comment received to its public docket,
submitted, or sent via email. For additional submission methods, the
full EPA public comment policy, information about CBI, and general
guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
FOR FURTHER INFORMATION CONTACT: Vasco Roma, Environmental Protection
Agency, Office of Air and Radiation, Office of Atmospheric Protection,
Climate Change Division; telephone number: 202-564-1662; email address:
[email protected].
SUPPLEMENTARY INFORMATION:
I. Background
Technologies with the ability to detect and measure atmospheric
methane have been advancing significantly over the last few decades.
These technologies are an important part of EPA programs, including the
recently finalized 40 CFR part 98 Subpart W (Subpart W) amendments,
which allow for the use of advanced measurement technologies to help
quantify methane emissions from Petroleum and Natural Gas Systems
sources, such as emissions from other large release events and flares
under the GHGRP.\1\ Similarly, the oil and natural gas New Source
Performance Standards and Emission Guidelines at 40 CFR part 60
Subparts OOOOb and OOOOc (``NSPS OOOOb/EG OOOOc'') published in March
2024 allow for the use of advanced measurement technologies to identify
the presence of Super Emitter Events and for detecting fugitive
emissions.\2\ In addition, the rules provide a pathway for
demonstrating that new technologies meet the performance requirements
established in the NSPS/EG rules. As a result, regulated entities are
able to leverage advanced measurement technologies that are already
available to detect methane emissions rapidly with accuracy, as well as
to incorporate new technologies that are emerging in this rapidly
evolving field.
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\1\ Final Greenhouse Gas Reporting Rule: Revisions and
Confidentiality Determinations for Petroleum and Natural Gas
Systems, 89 FR 42062 (May 2024).
\2\ Final Standards of Performance for New, Reconstructed, and
Modified Sources and Emissions Guidelines for Existing Sources: Oil
and Natural Gas Sector Climate Review, 89 FR 16820 (March 2024).
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Following requests for comment in the notice of the 2023 proposed
rulemaking for Subpart W,\3\ the EPA received numerous comments
requesting that the use of advanced measurement technologies be allowed
to quantify emissions from other sources beyond other large release
events in Subpart W. In response to these comments, EPA reviewed remote
sensing and in situ advanced measurement approaches (including both
intermittent and continuous monitoring approaches) that utilize
information from satellite, aerial, drone, vehicle, and stationary
platforms to detect and/or quantify methane emissions from oil and gas
operations for their potential use in Subpart W reporting. As a result
of this review and in response to comments on the proposed Subpart W
rule, in May 2024, EPA finalized additional options within Subpart W to
use advanced measurement technologies to measure data that are inputs
to emission calculations for flares and well completions and workovers,
in addition to the proposed use of advanced measurement technologies to
quantify emissions from other large release events and/or estimate the
duration of such events.
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\3\ Proposed Greenhouse Gas Reporting Rule: Revisions and
Confidentiality Determinations for Petroleum and Natural Gas
Systems, 88 FR 50282 (August 2023).
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As EPA acknowledged in the final Subpart W rule, advanced
measurement technologies are developing rapidly and are particularly
well-suited for detecting and quantifying large and discrete emissions
events, such as other large release events. Based on EPA's assessment
of the strengths and limitations of advanced measurement technologies
at the time of finalizing the Subpart W rule, however, EPA limited the
use of these technologies in annual GHG reporting to certain specific
roles identified in the final rule.\4\
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\4\ Final Greenhouse Gas Reporting Rule: Revisions and
Confidentiality Determinations for Petroleum and Natural Gas
Systems, 89 FR 42062 (May 2024).
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EPA has also sought comment on how methane monitoring technologies
might enhance emission estimates for other industrial sectors covered
under the GHGRP, specifically for MSW landfills under 40 CFR part 98
Subpart HH (Subpart HH). In a May 2023 notice of proposed rulemaking,
EPA requested examples of methane data collected from available
monitoring methodologies and how such data might be incorporated into
quantifying annual emissions.\5\ Although the EPA did not take final
action to incorporate advanced measurement technologies in the April
2024 final rule for the reasons described therein,\6\ including
information in comments received noting limitations in existing
technologies, EPA has continued to review ways to incorporate the use
of advanced measurement technologies into the emissions reporting for
MSW landfills for GHGRP reporting purposes under Subpart HH.
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\5\ Proposed Revisions and Confidentiality Determinations for
Data Elements Under the Greenhouse Gas Reporting Rule, 88 FR 32852
(May 2023).
\6\ Final Revisions and Confidentiality Determinations for Data
Elements Under the Greenhouse Gas Reporting Rule, 89 FR 31802 (April
2024).
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Based on these reviews, EPA recognizes that advanced measurement
technologies, and their use for annual quantification of methane
emissions, are evolving rapidly. EPA is committed to transparent and
continual improvements to its programs to ensure reporting is accurate
and complete. There are four key considerations associated with
expanding the use of advanced measurement technologies to quantify
annual methane emissions \7\ under the GHGRP in a robust, transparent,
accurate, standardized, and verifiable way:
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\7\ Current GHGRP reporting requires quantification of methane
emissions at the equipment-, process-, or facility-level. For
example, under Subpart W emissions are quantified and reported for
specific equipment types, such as pneumatic controllers. For Subpart
HH, emissions are quantified and reported at the facility-scale,
which includes the total surface area of the landfill, or for
specific processes such as landfill gas collection and control
systems.
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(1) How to translate the measurement data provided by different
types of advanced measurement technologies (e.g., methane plume images,
satellite retrievals of column methane mixing ratios, ambient methane
concentrations) into total tons of methane emissions.
(2) How to extrapolate methane emissions from discrete and
intermittent observations into total methane emissions throughout the
year (with a specific level of accuracy) and attribute these emissions
to a specific equipment type, process, or facility.
(3) How to identify, attribute, and quantify methane emission
events that are below a technology's detection limit, in order to
estimate total equipment-, process-, or facility-level emissions
throughout the year.
(4) How to set detection, quantification, attribution,
verification, and uncertainty criteria and/or protocols for different
types of advanced measurement technologies to ensure implementation
into the GHGRP in a manner that is applicable to different
infrastructures and environmental conditions across the U.S. (e.g.,
topographies, climates, facility types and layouts).
As technologies continue to rapidly advance to meet these needs,
EPA is issuing this RFI to the public to obtain information about
currently available advanced and emerging methane measurement
technologies, and how these technologies could be used to quantify
annual methane emissions from the oil and gas and MSW landfill industry
segments at the equipment-, process-, or facility-level for GHGRP
reporting purposes. The following questions are aimed to address the
key considerations outlined above and have been organized into the
following categories: quantification, attribution, and implementation.
EPA believes that standards or protocols could help ensure the use
of advanced measurement technologies to quantify annual methane
emissions is implemented in a transparent and standardized manner.
Furthermore, EPA anticipates that annual quantification approaches may
be specific to an emission source, facility type, or type of
technology. Therefore, a potential standard or protocol might be
specific to a type of methane source (e.g., hydrocarbon liquid storage
tanks, landfill working face) and a specific measurement approach
(e.g., drone, aircraft, vehicle-based, or multi-platform based). For
example, for a specific type of source, a potential standard or
protocol might include a detection limit below a certain methane
emissions rate threshold, a sampling frequency and duration (e.g., 1
overpass weekly) to ensure representative sampling of operating
activities throughout the reporting year, the inclusion of specific
ancillary data (e.g., wind speed and direction), and the use of a
transparent and peer-reviewed methodology (e.g., inverse analysis,
statistical sampling) to quantify the annual total methane emissions to
within a specified level of accuracy (e.g., 90%). To the extent that
information provided in response to the questions below are specific to
a particular emissions source, facility type, or technology type,
please indicate the applicability in the comments provided.
II. Questions
1. Quantification of Annual Emission Rates
EPA is requesting information on issues related to the
quantification of methane emissions using currently available advanced
measurement technologies, including: (1) detection and quantification
of methane emission rates; (2) approaches for extrapolating
observation-based methane emission rates to estimate annual total
emissions; and (3) approaches for quantifying annual total methane
emissions for sources that emit at rates below technology minimum
detection thresholds. Detailed questions on each topic are listed
below. Please provide detailed answers and citations to relevant
resources.
a. Detection and Quantification of Atmospheric Methane Emission Events
From Advanced Measurement Technologies
Advanced technologies for methane detection, such as instruments
deployed on satellite, aircraft, or in the form of continuous monitors,
can be used to detect methane emissions. These technologies do not
directly quantify methane emission rates but require additional
analytical tools and methods to transform the raw sensor measurements
(e.g., change in light attenuation) into quantified methane emission
rates (e.g., kg/hour) associated with each observation. Quantification
approaches can include but are not limited to the inverse analysis of
observed concentrations, the use of dispersion modeling, co-emitted
tracer releases, or mass balance approaches. Based on the wide variety
of detection and quantification approaches currently available, EPA
requests comment on the following:
i. What advanced measurement technologies are currently available
that can provide quantified methane emission rates using transparent,
open-source, and standardized methodologies? What are the specific
quantification approaches that have been used with these technologies,
and how have these methodologies been demonstrated and validated? How
can these technologies and quantification methodologies be used to
provide annual data in a consistent manner for each future year of
GHGRP reporting? Are there specific detection and quantification
approaches or methodologies that EPA should or should not consider?
ii. What performance metrics and threshold(s) related to
quantification would be appropriate to apply to advanced measurement
technologies for their incorporation into the GHGRP? For example,
should EPA consider: thresholds for the methane detection limit (e.g.,
minimum emissions leak rate), thresholds for the probability of
detection (e.g., rate of false positives or negative detections),
specific levels of accuracy for quantification, specific measurement
frequencies, or other? What would be a feasible approach for developing
these thresholds and metrics?
iii. Should quantification approaches be limited to the use of
specific methodologies (e.g., inverse analysis, mass balance) or
specific approaches for using ancillary datasets (e.g., standardized
interpolation of wind field products)?
iv. Are there ongoing efforts outside of EPA to develop standards
or protocols for methane emissions detection and quantification from
advanced measurement technologies that would address any of the
questions raised in this RFI? If so, please specify which efforts and
which question(s) can/will be answered and when these standards or
protocols will be publicly available.
b. Extrapolating Quantified Methane Emission Rates To Calculate Annual
Emissions for GHGRP Reporting Purposes
Different advanced measurement technologies provide data at
different sampling frequencies (e.g., continuous to weekly) and
durations (e.g., seconds to hours). Depending on the type of technology
and emissions source sampled, different approaches have been used to
extrapolate observation-based methane emission rates to estimate total
annual emissions for a specific region, facility, or site. These
approaches often require additional information on the frequency and
duration of the sampled emission events, information on the population
of sampled emission sources, site-specific
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operational activities, or statistical analytical approaches. EPA seeks
comment on the following:
i. What advanced measurement technologies are currently available
that can provide annual total methane emission estimates for specific
regions, facilities, processes, or equipment-level sources, that use
transparent, open-source, and standardized methods? Are these
technologies applicable across the entire U.S. and could they provide
annual data in a consistent manner for each future year of GHGRP
reporting? Are there specific annual extrapolation approaches or
methodologies that EPA should or should not consider?
ii. What accuracy or uncertainty metrics would be appropriate for
GHGRP reporting purposes? For example, what level of accuracy in
reported annual methane emissions should advanced measurement
technologies be required to meet? What sources of uncertainty are
necessary to consider? Are there other specific quality assurance or
quality control markers that should be considered to ensure that annual
estimates represent the methane emissions from all operational
activities throughout the reporting year, such as specific measurement
frequencies or duration? What would be a feasible approach for
developing these thresholds and metrics?
iii. To what extent should standards and protocols be specific to
the type of methods and ancillary data used (e.g., statistical
approaches), and to what extent should standards and protocols
simultaneously consider the specific type of emission sources being
sampled (e.g., large unintended vs. small routine emissions event)?
c. Quantifying Annual Methane Emissions From Emissions Sources Below
Detection Limits of Advanced Measurement Technologies
Different advanced measurement technologies also have different
detection thresholds (e.g., ~1 kg/hr to above 100 kg/hr), in part
dependent on the distance of the instrument from the source (e.g.,
typically larger detection limit for instruments on satellites compared
to aircraft), instrument type, and sampling strategy. In the current
GHGRP, a significant number of sources emit methane at rates below
these typical detection limits (e.g., a component leak will typically
emit at rates significantly below 1 kg/hr). To account for methane
emissions from these additional sources, various methodologies and
statistical approaches have been developed to estimate total annual
emissions to complement the data collected from advanced technology
measurements. EPA seeks comment on the following:
i. What methodologies are currently available for integrating
estimates of methane emissions for those sources emitting below
technology detection thresholds in an open-source, transparent, and
standardized way? Can these methodologies provide annual data in a
consistent manner for each future year of GHGRP reporting? Are there
specific approaches or methodologies that EPA should or should not
consider?
ii. Should these quantification approaches be limited to the use of
specific methodologies (e.g., Monte Carlo method) or specific ancillary
datasets (e.g., the use of standardized infrastructure or operator
data)?
2. Attribution
EPA is requesting comment and information regarding attribution of
quantified methane emissions (from discrete events or annual totals) to
specific GHGRP facilities, sites, or sources.
In addition to differences in temporal resolution, advanced
measurement technologies have spatial resolutions that can range from
kilometers (e.g., satellite) to site or individual equipment scales
(e.g., ground-based sensors). There are different approaches for
attributing observed events to a specific equipment type, process, or
facility depending on the specific type of technology used and sampling
distance from the emissions source. These approaches often require
ancillary information such as infrastructure data, site operator data,
or meteorological data such as wind speed and direction. EPA seeks
comments on the following:
a. What methodologies are currently available that can attribute
quantified methane emission events to specific equipment types (or
additionally, specific regions, facilities, or processes) using
transparent, open-source, and standardized methods? Are there specific
attribution approaches or methodologies that EPA should or should not
consider?
b. What accuracy or uncertainty metrics would be appropriate for
GHGRP reporting purposes? For example, what level of confidence in the
source attribution would be necessary for advanced measurement
technologies to meet for GHGRP reporting purposes? What would be a
feasible approach for developing these thresholds?
c. To what extent would standards and protocols need to be specific
to the type of methods and ancillary data used (e.g., infrastructure
datasets) or the type of emission source sampled (e.g., large
unintended vs small routine emissions event)?
3. Implementation
EPA is requesting comment and information on issues related to the
implementation of advanced measurement technologies into the GHGRP.
Implementation considerations include the need for quantifying
annual total methane emissions from oil and gas and MSW landfill
applicable sources across the U.S. in a transparent and standardized
way, validation and verification of the reported data, and additional
potential uses of advanced measurement technologies for the GHGRP. EPA
also requests information on additional data that could be reported for
the verification of methane emissions estimates produced using advanced
measurement technologies.
a. Structure of Approaches or Protocols
i. What form would standard method(s) or protocol(s) need to take
to ensure that advanced measurement technologies provide annual total,
source-specific, methane emissions in a transparent and standardized
way? For example,
(1) To what extent should standards and protocols be specific to
the type of methods used (e.g., satellite, aircraft, ground-based)? In
addition, would different standards or protocols be necessary for
sampling approaches using single platform vs. multi-platform
measurements? Could standard methods be developed to be technology
agnostic?
(2) To what extent could standard method(s) be developed to be
source agnostic? For example, would standards need to be specific to
the type of equipment, process, or emission source sampled (e.g.,
tanks, flares, pneumatic devices, landfill working face), or could a
set of standard(s) be developed to be more broadly applicable across
different GHGRP industry segments (e.g., oil and gas operations and
landfills)? Alternatively, would different standards be necessary for
different types of methane emission events sampled (e.g., large
unintended vs small routine emissions events)?
b. Verification and Validation of Annual Source-specific Methane
Emission Quantification Methods Using Advanced Measurement Technologies
for GHGRP Reporting Purposes
i. Are there approaches currently available that could be used to
verify that advanced measurement technologies meet specific standards
(e.g., independent blind studies,
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deployment of calibration standards, other)?
ii. Is it necessary to limit the applicability of advanced
measurement technologies to environmental and site conditions that have
been previously validated? For example, if an advanced measurement
technology has been validated through blind control release testing
during which wind speeds ranged from 0.5 to 10 m/s, should the
technology be limited to measurements within this range of wind speeds?
What form of validation could be used to demonstrate whether a
technology is applicable across environmental conditions outside of
their tested ranges?
iii. Are there specific types of operator- or facility-specific
information that would be useful for improving or validating annual
methane emissions quantification or source attribution from advanced
measurement technologies?
c. Other Considerations Related to the Use of Advanced Measurement
Technologies for GHGRP Reporting Purposes
i. What (if any) are the current barriers or limitations to using
advanced measurement technologies beyond what is currently allowed
under the GHGRP to quantify annual equipment-level methane emissions at
scale in the U.S.?
ii. What are the cost considerations for implementing different
advanced measurement technologies to quantify annual, equipment-,
process-, or facility-level methane emissions for GHGRP reporting
purposes? If available, costs should be provided in a manner that can
be scaled up to different implementation approaches (e.g., cost per
site, cost per area covered).
iii. How are factors such as measurement and analysis cost,
complexity, or time burden relevant for determining whether advanced
measurement technologies may be appropriate for annual GHGRP
application?
iv. Other than methane emissions detection and quantification, and
establishing the duration of emission events as permitted under Subpart
W for Other Large Release Events, are there additional ways in which
advanced measurement technologies could be used to support
quantification and reporting of equipment-, process-, or facility-level
methane emissions to the GHGRP (e.g., as a method to identify changes
in operating conditions, to supplement specific reported data
elements)?
Sharyn Lie,
Director, Climate Change Division.
[FR Doc. 2024-19403 Filed 8-28-24; 8:45 am]
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