In Q4 2021, the EPA released proposed subparts NSPS OOOOb and NSPS OOOOc as well as revisions to the existing NSPS OOOOa. In a nutshell, NSPS OOOOb would pertain to VOC and methane reduction on constructed, modified and reconstructed sources after 11/15/21. NSPS OOOOc would have a few differences (detailed below) from OOOOb, and would provide emissions guidelines for state use, to develop and implement methane reduction performance standards for existing oil and gas sources.
As of October, 2022, the EPA has finished writing the rule text and will publish the rules in the Federal Register soon. Therefore this briefing serves as an update to what these rules require and how it will affect oil and gas operators and industry professionals:
NSPS OOOOa (revision)
Applies to facilities constructed, modified or reconstructed after September 18, 2015.
· An update to the existing subpart to rescind parts of a 2020 technical amendment.
· Returns to quarterly monitoring for compressor stations
· Removal of low production well exemptions.
NSPS OOOOb
Applies to sources, constructed, reconstructed, and modified after the publication date in the Federal Register. Regulates methane and VOC. A revision to the existing subpart.
· Compressor Station: would require quarterly monitoring of compressor stations
· Well Site: would require quarterly monitoring at well sites greater than 3 TPY
· Well Site: would require quarterly monitoring at well sites ≥3 and >8 TPY methane
· Well Site: would require semiannual monitoring at well sites < 3 TPY Methane
· Storage Tanks: includes single storage tanks as well as tank batteries with PTE greater than or equal to 6 TPY VOC. Affected tanks or tank batteries require 95% emission control.
· Reciprocating Compressors: not located at a well site* annual monitoring of the rod packing emissions using flow measurement. When the measured leak rate is >2 scfm (in pressurized mode), replace the rod packing or route emissions to a process through a closed vent system.
· Wet Seal Centrifugal Compressors: not located at a well site* require 95% control.
· Pneumatic Controllers: Zero-emissions controllers. This can be achieved through instrument air supply.
· Pneumatic Pumps: 95% control of diaphragm pneumatic pumps if there is an existing control or process on site. 95% control not required if (1) routed to an existing control that achieves less than 95% or (2) it is technically infeasible to route to the existing control device or process.
· Well Liquids Unloading: Perform liquids unloading with zero methane or VOC emissions. If this is not feasible for safety or technical reasons, employ best management practices to minimize venting. For more detail on co-proposal options please visit the federal register rule publication.
· Oil Well Associated Gas: Route associated gas to a sales line. If access to a sales line is not available, the gas can be used as an onsite fuel source, used for another useful purpose that a purchased fuel or raw material would serve, or routed to a flare or other control device that achieves at least 95% reduction in methane and VOC emissions.
NSPS OOOOc
Pertains to existing sources on or before November 15, 2021, and focuses on regulating methane. The standards for OOOOc are nearly identical to OOOOb; however, this proposed rule includes emissions guidelines for state regulatory agencies to follow, for implementation of state plans regarding methane limitations for existing sources. Key differences from OOOOb:
· Storage Tank Battery: (PTE ≥ 20 TPY Methane): 95% control
The standards for OOOOc are nearly identical to OOOOb; however, this proposed rule includes emissions guidelines for state regulatory agencies to follow, for implementation of state plans regarding methane limitations for existing sources.
· Pneumatic Controllers: applies to natural gas driven controllers that vent to atmosphere, whereas NSPS OOOOb applies to all-natural gas driven controllers, both continuous and intermittent bleed
