Regulatory update: Q&A on proposed EPA methane regulations

Name of regulation: Greenhouse Gas Reporting Rule: Revisions and Confidentiality Determinations for Petroleum and Natural Gas Systems

Stage: Proposed rule

Agency: U.S. Environmental Protection Agency (EPA)

On August 23, 2023 we had a webinar discussing proposed EPA methane regulations. You can watch the recording to see the whole thing. We got some great questions from the audience, and we are sharing the Q&A here. 

When will OOOOc be final?

 EPA has publicly stated their intent to finalize both Subparts OOOOb and OOOOc this calendar year. The rules will go through an internal review process before going to the White House Office of Management and Budget (OMB) for interagency review. The OMB review process could take anywhere from 30-90 days once it is submitted to OMB. That hasn’t happened yet, so the timing is not clear at this point. 

Are pneumatic pumps counted in the pneumatic device category for measurement options?

The webinar presentation focused specifically on pneumatic devices, which are separate from pneumatic pumps.  However, EPA did propose similar direct measurement options for pneumatic pumps in the July 2023 proposal. The proposed calculation methods include:

1. Direct measurements using flow meters installed on the natural gas supply line dedicated to one or more pneumatic pumps
2. Direct measurements where no flow metering device is installed by measuring the natural gas emissions from each pneumatic pump venting to atmosphere as required in 98.233(c)(2) 
3. Use of default population factors (note: EPA did not propose any changes to the default factors in the rule, but did propose a clarification of the definition of the term “T” in equation W-2 by replacing the word “operational” with “pumping liquid”

Do Subpart W requirements only apply to facilities constructed/modified in 2025 and beyond? Or to all existing and new facilities since it is not NSPS?

In short, no. There are different applicability definitions for Subpart W and the NSPS rules. Reporting under Subpart W is required for any facility that emits 25,000 metric tons of CO2e or more per year. There is no consideration of new vs existing for reporting purposes. The NSPS apply based on dates of construction, reconstruction, and modification for individual affected facilities (e.g., wells, pumps, controllers, tanks). 

Are measurements going to be allowed for combustion emissions (methane slip), or would that be strictly emission factor based for Subpart W?

EPA proposes three calculation methodologies for combustion emissions (methane slip). These include:

1. Performance testing
2. Original equipment manufacturer information, which may include manufacturer specification sheets, emissions certification data, or other manufacturer data providing expected emission rates from the reciprocating internal combustion engine or gas turbine
3. Default emissions factors for the applicable equipment type provided in table W– 7 of Subpart W

Is EPA thinking about auditing the reported data now that operators may shift from factors to measurement based? And are issues regarding accuracy of reporting subject to enforcement?

This is a great question, but I do not think the proposal provides enough insight to understand what EPA’s thoughts may be on this. However, this topic came up in the public hearing on Monday, August 21. Several speakers requested that EPA require independent auditing of all self-reported measurements. They did not provide specific examples of what those independent audits could look like, but EPA will have to respond to those comments when they issue the final rule. 

Do you view Subpart W as currently written as disincentivizing alternative detection technologies? Do you think this will change to incorporate alternative technologies as approved options for measurement.

The proposed revisions to Subpart W do not appear to directly address the use of alternative detection technologies. There is acknowledgement that these technologies can be useful for identifying large emission events, and the possible use of these technologies for leak detection, but EPA has not proposed any direct pathways or methods for their use. This topic was also discussed by several speakers at the public hearing, many of which requested that EPA incorporate more top-down and basin-level emissions measurements into the reporting program. EPA does solicit comments on how it should consider incorporating alternative detection technologies into the rule, so I would encourage providing data and comments on this topic.

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