The Environmental Protection Agency (EPA) issued a supplemental proposed rule intended to reduce US methane emissions in the oil and natural gas industry.
Section 111(b) of the Clean Air Act (CAA) authorizes the EPA to establish New Source Performance Standards (NSPS) for new, modified, and reconstructed sources of air pollutants (42 U.S.C. § 7411(b)). NSPS require affected sources to comply with emissions limits based on the best system of emission reduction (BSER) adequately demonstrated for that type of source.
CAA § 111(d) also requires the EPA to adopt regulations under which states will enforce performance standards for existing sources of air pollution that both:
Would be subject to NSPS if they were new, modified, or reconstructed sources.
Are not already regulated under other sections of the CAA.
The oil & gas industry is the largest industrial contributor to US methane emissions. Methane is a potent greenhouse gas (GHG) and significantly contributes to climate change. In recent years, the EPA has adopted various NSPS for emissions from oil & gas sites, including NSPS for methane emissions in 2016. EPA regulations currently include NSPS for methane and volatile organic compound (VOC) emissions from new, modified, and reconstructed oil & gas sources including:
In response to President Biden's Executive Order 13990, "Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis" and to carry out international commitments by the US to cut methane emissions, the EPA issued the 2021 Proposed Rule to:
Adopt additional NSPS regulations for methane and VOC emissions from oil & gas sources.
For the first time, regulate VOC and methane emissions from existing oil & gas sources under CAA § 111(d) by adopting regulations setting emission guidelines (EGs) for those sources.
The 2021 Proposed Rule did not include the text of the proposed NSPS and EG regulations. Instead, the EPA sought public comment on all aspects of the proposed rules and stated that it intended to issue a supplemental rule proposal including proposed text for the new NSPS and EGs. The EPA received over 470,000 written comments on the 2021 Proposed Rule.
Key Changes in the Supplemental Proposed Methane Rule
The Supplemental Proposal builds on and expands many requirements in the 2021 Proposed Rule, including making the following key changes:
Regular emissions monitoring for all well sites. Unlike the 2021 Proposed Rule which contemplated regular emissions monitoring for only a subset of oil and gas wells, the Supplemental Proposal would require periodic fugitive emissions monitoring of all well sites and compressor stations. Depending on the site, monitoring may require:
quarterly, monthly, or bimonthly audio, visual, and olfactory (AVO) leak inspections;
quarterly or semi-annual inspections using optical gas imaging (OGI) or EPA Method 21; or
both periodic AVO and OGI inspections.
Use of advanced methane detection technology. Building on the 2021 Proposed Rule, the Supplemental Proposal would allow the use of a broader range of advanced technologies in lieu of OGI or other leak detection methods and tie the frequency of required monitoring surveys to the detection ability of the technology used.
Monitoring required until well plugging. The Supplemental Proposal would require monitoring to continue at well sites until:
all wells have been plugged and equipment has been removed;
the owners submit a required well closure plan; and
the owners conduct a final survey using OGI to ensure no emissions are found.
Super-emitter response program. The Supplemental Proposal includes a super-emitter response program to quickly identify large methane leaks and emissions events. Under the proposed program:
regulatory authorities or EPA-approved private parties could notify owners and operators of regulated sites when a super-emitter event (100 kilograms of methane per hour or more) is detected; and
the owners and operators would be required to determine the cause of the event and promptly correct it.
Additional requirements for flares. The Supplemental Proposal includes additional measures to reduce emissions from flaring of gas, including requirements:
to continuously monitor flares to ensure that a pilot flame burns at all times; and
that owners or operators submit a certified demonstration that a gas sales line is not available and that other beneficial uses are not feasible before flaring.
Updating NSPS for pneumatic pumps and compressors. The Supplemental Proposal proposes to:
set a zero-emissions standard for pneumatic pumps; and
update the NSPS for certain compressors and establish NSPS for dry seal compressors.
Proposed Text of the New NSPS and Emission Guidelines
New Source Performance Standards
The EPA published the proposed text of the new NSPS as part of the proposal. Under the current proposal, the new NSPS apply to facilities built, modified, or reconstructed after November 15, 2021.
Rather than allowing the EPA to set emissions standards for existing sources, CAA §111(d) requires the EPA to promulgate regulations under which states make implementation plans to adopt and enforce emissions standards. If a state fails to submit a satisfactory plan, the EPA must promulgate and enforce a federal plan. The EGs include requirements for state implementation plans along with presumptive emissions standards for regulated sources. In most cases, the presumptive standards are the same or similar to BSER in the proposed NSPS. In preparing state plans, states may either:
Adopt the presumptive standards.
Use state standards of performance, if the state demonstrates they are equivalent to the federal standards based on criteria in the EG regulations.
Under the proposed EGs:
State plans would be due 18 months after the publication of the final EG rule in the Federal Register.
Existing sources would be required to comply with the new performance standards 36 months after the plan submission deadline.
Expected Benefits and Costs of the Supplemental Proposal
The EPA estimates that in 2030, the Supplemental Proposal would reduce methane emissions from covered sources by 87% from 2005 levels (compared to 74% under the 2021 Proposed Rule). The EPA further estimates that the Supplemental Proposal would:
Avoid 36 million tons of methane emissions from 2023 to 2035.
Avoid 9.7 million tons of VOC emissions from 2023 to 2035 and 390,000 tons of emissions of toxic air pollutants including benzene and toluene.
Result in $34 to $36 billion in climate benefits from 2023 to 2035 ($3.1 to $3.2 billion annually).
Increase recovery of natural gas valued at $3.3 to $4.6 billion from 2023 through 2035.
The EPA estimates compliance costs of the proposed regulations over the period from 2023 to 2035 to be $19 billion using a three percent discount rate and $15 billion using a seven percent discount rate.
The EPA is soliciting comments on the Supplemental Proposal and has published a memo listing specific subjects on which comments are requested. Comments must be received by February 13, 2023. The EPA is additionally holding a virtual public hearing on the proposal on January 10-11, 2023. The EPA expects to adopt a final rule in 2023.
The regulations also increase regulatory burdens on the oil & gas industry, especially for operators of existing oil & gas wells and upstream infrastructure that are not already subject to NSPS. Of particular industry concern:
The requirement to conduct monitoring on all existing oil and gas wells until they are plugged could substantially affect oil & gas operators with many older, low-producing wells. A January 2022 report by the Energy Information Administration (EIA) estimates there were over 930,000 producing oil and gas wells in the US as of 2020, most of which produce less than 15 barrels of oil equivalent per day.
The EG regulations may significantly impact some types of older oilfield equipment that would need to be modified or upgraded to meet performance standards.
The super-emitter response provisions potentially allow environmental groups or private citizens to obtain EPA approval to help enforce the new regulations.