The Department of Environmental Protection announced Thursday it has finalized revisions to a general permit for natural gas-fired engines and equipment at compressor stations, which help move gas from well sites into transmission pipelines.

The revised general permit includes significantly lower allowable emission limits than the previous general permit, called GP-5.

DEP also announced it will accept public comment on a proposed plan approval and operating permit exemption for air emission sources at well drilling sites. Well sites would only be eligible for the exemption for the air quality plan approval process if the wells will meet emission control and monitoring criteria that are stricter than federal air quality rules for controlling wellhead emissions. The plan approval authorizes construction of facilities that emit certain types and amounts of pollutants.

Formal notices announcing the final revised GP-5 and the proposed exemptions to air quality plan approval regulations will appear in the February 2 edition of the Pennsylvania Bulletin. DEP will accept comments on the proposed changes until March 19.

“Pennsylvania has seen improved air quality over the past decade, and the United States led the world in greenhouse gas emission reductions over the past five years, in great part due to shale gas,” DEP Secretary Mike Krancer said. “This shift in the way we approach emissions will help us continue these trends.

“The steps we are taking now mean far lower emissions at well sites and more efficient compressor stations, resulting in cleaner air as development, production and transmission take place,” he said. “DEP’s effective and robust oversight will deliver on the promise of cleaner air from the increased use of natural gas.”

The final revisions to GP-5, which were developed after considering public comment, impose emissions limits that are 75 to 90 percent stricter than current limits for the largest, most common types of engines used at compressor stations. Notably, the revised permit also affords operators the ability to install controls to achieve even lower emissions, allowing for the use of additional engines.

“Essentially, we are doing much more by setting these limits as a line the operator cannot cross. This is an improvement in air quality protection,” Krancer said. “We are also determining compliance based on the facility’s actual emissions, instead of equating the permit’s limits with the facility’s emissions, as was previously done.”

Operators of facilities permitted by the GP-5 must demonstrate that their facilities continue to be minor sources as defined by the Clean Air Act, allowing for operational flexibility.

DEP is also proposing a revision to one section of its air quality permit exemption list that governs which types of facilities do need to obtain a plan approval prior to construction. The proposed exemption would apply to wellheads and their associated storage tanks.

The proposed exemption requires drillers to control emissions more stringently and conduct leak detection on the entire wellhead, which is more comprehensive than is currently required by federal air quality rules for oil and gas development. The U.S. Environmental Protection Agency released these rules, called New Source Performance Standards, in April 2012.

Operators of all newly drilled oil and gas wells would be required to decide between demonstrating eligibility for the exemption or applying for a plan approval after the proposed exemption regulations are finalized.

A copy of the GP-5 permit is available on DEP’s Air General Permit webpage.  The proposed exemption of certain oil and gas development activities is available in the February 2 PA Bulletin.

Related Story: RAND: Air Emissions From PA Natural Gas Facilities Cause Millions In Damage

NewsClips:

PA Moves To Limit Air Emissions From Natural Gas Industry

DEP Plans New Pollution Limits For Well Sites, Compressors

Data Says Gas Industry Creates Fraction Of Air Pollution

DEP Reports Air Pollution From Shale Gas Industry

2/4/2013