Pipeline VOC Emission Limits Soon To Be Finalized; EPA Makes Changes To Pipeline GHG Reporting Rule

February 2012, Vol. 67 No. 2

Natural gas transmission companies are very unhappy with the EPA's decision to tighten industry air emission limits. A consent decree signed by the EPA requires the agency to revise both New Source Performance Standards (NSPS) and national emission standards for hazardous air pollutants (NESHAP) for the natural gas industry, including for pipelines, by the end of February. Those are two separate EPA regulatory programs.

The upcoming February NSPS rule will regulate transmission pipelines for the first time and require emission reductions from pneumatic controllers, centrifugal and reciprocating compressors. The transmission NESHAP, established in 1999, would be revised to include "small" glycol gas dehydrators. Both regulatory programs seek to reduce emissions of volatile organic chemicals (VOC) from numerous pipeline sources.

Lisa Beal, vice president, Environment and Construction Policy, Interstate Natural Gas Association of America (INGAA), says VOC emissions from pipelines are insignificant. She calls the EPA decision to subject transmission pipelines to NSPS standards "questionable and not adequately supported." She adds, "It appears that the proposed NSPS is a thinly veiled attempt to regulate transmission and storage greenhouse gas emissions."

She argues that the EPA should not classify a pneumatic controller, which is a trivial VOC source and an equipment sub-component, as a “facility" under the NSPS. The NSPS would also require pipelines to equip centrifugal compressors with dry seal systems. But the EPA may allow a compliance option of wet seals combined with routing of emissions from the seal liquid through a closed vent system to a control device. Beal says only new centrifugal compressors should be regulated, and that wet seals should be allowed if the operator can demonstrate that VOC emissions are similar to dry seal missions.

There would be standards for reciprocating compressors, too. They would require replacement of the rod packing after 26,000 hours of operation are reached. With regard to reciprocating compressor rod packing requirements, Beal states those should be based on 35,000 operating hours and include an option to use condition-based maintenance to extend the operation of functional rod packing.