On October 1, 2024, the EPA approved Pennsylvania’s proposed state implementation plan (SIP) revision for its “Existing Source Rule” Regulations. Codified in Title 25, Chapter 129 of the PA Code, Sections 121 through 130, the rules establish requirements for the control of VOC emissions from unconventional oil and natural gas sources. The rule contains compliance, recordkeeping, and reporting requirements for various equipment constructed at unconventional well sites, gathering and boosting stations, or natural gas processing plants on or before December 10, 2022.

Following the EPA’s release of the “Final Control Techniques Guidelines for the Oil and Natural Gas Industry” (EPA’s 2016 Oil and Gas CTG), Pennsylvania was required to establish Reasonably Available Control Technology (RACT) requirements for sources in the CTG to address the 2008 and 2015 Ozone National Ambient Air Quality Standard (NAAQS) due to its location in the Ozone Transport Region.

Pennsylvania identified and regulated the following sources of VOC emissions constructed at an unconventional well site, gathering and boosting station or natural gas processing plant on or before December 10, 2022:

• Storage vessels
• Natural gas-driven continuous bleed pneumatic controllers
• Natural gas-driven diaphragm pumps
• Reciprocating compressors and centrifugal compressors
• Fugitive emissions components; and
• Covers, closed vent systems, and control devices used by the above sources to comply with rule’s emission control requirements.

Storage vessels constructed in the natural gas transmission and storage segment on or before December 10, 2022 are also subject.

Compliance Requirements

Storage vessels with potential and actual emissions exceeding 2.7 ton per year (TPY) on a 12-month rolling basis must route VOC emissions to a control device or a process to achieve a 95% reduction.

Natural gas-driven continuous bleed pneumatic controllers at unconventional well sites and gathering and boosting stations must maintain a natural gas bleed rate of less than or equal to 6 standard cubic feet per hour (scfm). Natural gas-driven continuous bleed pneumatic controllers at natural gas processing plants must maintain a natural gas bleed rate of 0 scfm.

Natural gas-driven diaphragm pumps must route VOC emissions to a control device or a process and demonstrate 95% reduction. Alternatively, the operator can obtain an assessment of technical infeasibility from an in-house engineer or a professional engineer (PE) to be exempt from control requirements.

Reciprocating compressors located between the wellhead and point of custody transfer to the natural gas transmission and storage segment are required to replace rod packing after 36 months or 26,000 operational hours.

Centrifugal compressors must reduce VOC emissions from wet seals route VOC emissions to a control device or a process to achieve a 95% reduction. Centrifugal compressors located at (or adjacent to and serving) an unconventional well site are exempt from VOC emission limitations and control requirements.

Well sites must calculate their average production in barrels of oil equivalent per day (BOEd) for the previous 12 months of operation by February 15th of each calendar year to assess their applicability to leak detection requirements under the rule:

• If at least one well produces, on average, equal to or greater than 5 BOEd but less than 15 BOEd, fugitive emission components must undergo monthly AVO inspections and annual LDAR surveying.
• If at least one well produces, on average, equal to or greater than 15 BOEd, fugitive emission components must undergo monthly AVO inspections and quarterly LDAR surveying.

Gathering and boosting stations and natural gas processing plants are required to survey their fugitive emission components with monthly AVO inspections and quarterly LDAR.

All facilities conducting inspections on their fugitive emission components to comply with the Existing Source Rule must develop, in writing, a fugitive emission monitoring plan.

Covers and closed vent systems must be inspected by AVO monthly for defects. Applicable closed vent systems must also undergo a no detectible emissions inspection during the facility’s scheduled LDAR surveys and each system must obtain a design and capacity assessment from an in-house engineer or PE.

Control device compliance requirements vary by control technology, but a physical integrity check of all applicable control devices must be performed monthly. Additionally, devices with pilot flames have continuous parameter monitoring system (CPMS) and monthly EPA Method 22 requirements. Complete compliance requirements for each control technology are outlined in Pa. Code §129.129(c) – (i).

Reporting Requirements

Starting in 2023, unconventional facilities subject to the Existing Source Rule are required to submit an annual compliance report to the appropriate PA Department of Environmental Protection (PADEP) Regional Office by June 1 of each year. Annual compliance reports include information related to reciprocating compressor rod packing changes, AVO inspections/LDAR surveys, Method 22 visible emission tests, physical integrity checks, control device compliance, and deviations from the requirements of the rule.

NOTE: The EPA also approved the SIP revisions for Control of VOC Emissions from Conventional Oil and Natural Gas Sources (codified in Title 25, Chapter 129 of the PA Code, Section 131 through 140). As of the publishing of this article, the Existing Source Rule for “conventional” facilities is stayed in the Commonwealth Court of Pennsylvania. PADEP has announced it will not be enforcing rule as it is being litigated, however, in the announcement of approval for the revision to the PA SIP, EPA stated the “conventional” and “unconventional” rules are nearly identical and have no technical differences and approved the plan for both rules.

If you have questions regarding the potential impact or reporting of these regulations, please contact our Pittsburgh office at 724.935.2611 or our Philadelphia office at 610.280.3902.