*Note that page numbers refer to the Internet version of the rule posted on November 11, 2022. They will be replaced when the official version of the rule is published in the Federal Register.
On November 11, 2022, the EPA released its supplemental notice of proposed rulemaking for EPA-HQ-OAR-2021-0317: Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources: Oil and Natural Gas Sector Climate Review. The supplemental rulemaking provides wide-ranging amendments to the draft proposal released one year prior, in response to the more than 470,000 public comments and responses to solicitations for public input.
LongPath Technologies is pleased to report that the supplemental notice correctly identifies high-frequency monitors with the capability to quantify valid mass emission rates with a low threshold of detection as the gold standard of monitoring, and, as such, positions this technology class as an important alternative that can be used for regulatory compliance in monitoring for methane. In defining continuous monitors thusly, EPA sets a high bar that will drive continued advancement and refinement of domestic and international standards for low emissions oil and natural gas products.
EPA’s default (BSER) regulatory program remains OGI camera or Method 21 sweeps, but new provisions allow compliance with alternative technologies.
The five categories of sites and their proposed respective BSER monitoring requirements are1:
Importantly, all well sites will require monitoring until such time as all wells on that site have been adequately plugged and all equipment removed. The development that all sites will require some form of ongoing monitoring, combined with the relatively high cadence of inspections required at most sites, will both support continued adoption of advanced alternatives.
The EPA proposes two pathways for alternative technologies to provide compliance: survey monitoring and continuous monitoring.
For survey monitoring, a set of matrices define survey frequency requirements and associated minimum detection thresholds based on the site type and size2. For example, the largest detection threshold tier (technologies capable of detecting 30 kg/hr leaks) requires monthly surveys combined with annual OGI inspections. For alternative monitoring based on surveys, follow-up on detected leaks requires OGI inspections (not simply root cause and corrective action)3.
For continuous monitoring, compliance requires the use of technologies that can provide site-level quantified emission rate readings at least once every 12 hours at a low threshold of detection4. Root cause and corrective action are required in either of two cases: 1) if rolling 90-day average emissions exceed 1.2 kg/hr (1.6 kg/hr) for wellhead-only (all other sites and compressor stations), and 2) if rolling 7-day average emissions exceed 15 kg/hr (21 kg/hr) for wellhead-only (all other sites and compressor stations)5. An important distinction between this and the survey-based alternative monitoring is that operators are allowed to find and fix leaks without the requirement of OGI follow-up6. This element provides some incentive for operators to use higher-frequency continuous rather than lower-frequency survey monitoring.
The below table shows the BSER and alternative options for each site type.
Allowable continuous monitoring sensor systems must meet several important criteria. The temporal frequency of each emission rate reading is every 12 hours to observe full-site emissions10.The required minimum detection level for the continuous monitoring system is one order of magnitude less than the proposed action level11. Given the proposed action levels of 1.2 kg/hr and 1.6 kg/hr for long-term alerts and 15 kg/hr and 21 kg/hr for short-term alerts, this requirement can be interpreted to mean that the required minimum detection levels will be on the order of 0.1 to 0.2 kg/hr. Finally, continuous monitoring systems are required “to produce a valid mass emissions rate (i.e., kg/hr)”; technologies without valid quantification will not be considered compliant for continuous monitoring. Non-quantifying continuous camera systems are specifically noted as not suitable12.
LongPath Technologies’ ability to provide full-site quantification on a short timeframe (<12 hours) with a very low threshold of detection (order .1 to .2 kg/hr) sets it squarely in compliance with the proposed rule. Other continuous monitoring systems may require many sensors to meet the EPA rule requirements of site-wide coverage, valid quantification, and a low detection threshold.
The definition of a clear and technology-neutral pathway for alternative technologies to be used in lieu of the BSER requirements is a major advancement in EPA’s regulation of methane emissions. Importantly, the designations for BSER and alternative compliance are based in mathematical models for emissions reduction equivalency, a change in precedent toward a regulatory framework that is based on scientifically rigorous methods that can grow with our collective understanding of emissions and mitigation needs.
The EPA has also taken the forward-looking approach of applying emission rate action levels (i.e., based on quantified volumetric loss rates) rather than concentration-based action levels (i.e., based on ambient air measurements decoupled from actual emissions), as was the precedent from the Refineries NESHAP (National Emissions Standards for Hazardous Air Pollutants)13. The EPA also takes a highly forward-looking step of requesting comment on the use of methane intensity values for triggering action with continuous monitors14. This is an important opening for change in the final rule, given that actual emission rates vary widely from basin-to-basin; a 1.6 kg/hr alert threshold in the Permian might give rise to frequent alert triggers on some sites, while alerting far less often in the Marcellus.
The EPA proposes a streamlined process for the approval and use of alternative technologies15. Technologies may apply for approval under alternative test method provisions, with an Agency deadline of 270 days to respond. Alternative approaches are broadly applicable; operators do not need to request agreement for their use once they are approved. Further, operators may develop site-specific monitoring plans or develop monitoring plans that cover multiple sites16. The EPA further proposes a set of 4 pre-qualifications for approval - which LongPath meets. Overall, these developments significantly reduce the time and burdens for use of alternative technologies in comparison with the AMEL process.
Finally, the EPA’s approach toward community-based monitoring for fugitive emissions took shape in the form of the proposed super-emitter response program, in which certified entities may submit credible evidence of super-emitter events collected from aircraft, satellite or mobile surveys17. These fugitive leak detections will require owners or operators of the reported assets to undertake root-cause and corrective actions.
In all, we believe these changes will allow operators to gain significant operational flexibility, cost reductions, and revenue retention by using LongPath over more traditional LDAR programs.
A public comment period will close in mid-February, with public hearings to take place in January. The final rule will be issued in 2023.
1. See Table 2 – Summary of proposed BSER and proposed standards of performance for GHGs and VOCs (NSPS OOOOb), beginning Page 25, and Table 3 – Summary of proposed BSER and proposed presumptive standards for GHGs from designated facilities (EG OOOOc), beginning Page 31.
2. Page 135 and Table 20 – Survey matrix for alternative periodic screening approach for affected facilities subject to quarterly OGI monitoring and Table 21 – Survey matrix for alternative periodic screening approach for single and multi-wellhead only sites and small well sites.
3. Page 138.
4. Page 144.
5. Page 142.
6. Page 143.
7. See Table 2 – Summary of proposed BSER and proposed standards of performance for GHGs and VOCs (NSPS OOOOb), beginning Page 25, and Table 3 – Summary of proposed BSER and proposed presumptive standards for GHGs from designated facilities (EG OOOOc), beginning Page 31.
8. Page 135 and Table 20 – Survey matrix for alternative periodic screening approach for affected facilities subject to quarterly OGI monitoring and Table 21 – Survey matrix for alternative periodic screening approach for single and multi-wellhead only sites and small well sites.
9. Page 142.
10. Page 144.
11. Page 144.
12. Page 144.
13. Page 141.
14. Page 142.
15. Pages 146-150.
16. Page 137.
17. Page 153.