Subpart W Rule Out Early… Now What Do We Do?

The ruling on “Revisions and Confidentiality Determinations for Petroleum and Natural Gas Systems” has been finalized effective January 1, 2025, and once published in the Federal Register, will trigger a few amendments effective 60 days later. As anticipated based on the proposed Subpart W rule, EPA has followed through on adding several new emission sources including other large release events, produced water storage tanks, nitrogen removal units, drilling mud degassing, and crankcase venting. There will also be the expected change to disaggregate basin-level facilities down to the well pad or gathering and boosting sites. In terms of additional calculation methodologies and empirical data as an alternative to population factors, reporters will have the option to choose what they use - even in 2024 reporting. This applies to equipment leaks, combustion slip, crankcase venting, associated gas, compressors, and pneumatics. Thankfully, this latest rule aligns with the Quad O rule on methods for direct emissions measurement.  

Based on comments received, there are some proposed changes that have been tabled for now with a caveat that they may surface again when the proposed “Waste Emission Charge” is finalized [August 2024 at the latest]. For example, prescriptive requirements initially proposed to determine flow and composition of gas routed to flares have been removed. Additionally, the proposed separate large emission threshold of 250 mt CO2e per event has been deemed duplicative of the 100 kg/hr threshold and therefore removed. Overall, the rule has been released somewhat earlier than expected giving Subpart W reporters about six months to digest and implement the best plan for reporting 2024 data and assessing what 2025 will, or perhaps better said, can, look like.

Please reach out to our Consulting team at Pickering Energy Partners to discuss how we can help at