Pennsylvania’s Department of Environmental Protection (DEP) has finalized revisions to general permits for natural gas-fired engines and equipment at compressor stations, which are “75-90%” stricter than current limits for the largest, most common types of engines used at compressor stations. DEP also is suggesting revisions to one section of the air quality permit exemption list governing well drilling sites.
The final revised GP-5 permits give operators the ability to install controls to achieve the lower emissions and allow additional types of engines to be used. Operators of facilities permitted by the revised GP-5 would have to demonstrate that the facilities remain “minor sources,” as defined by the U.S. Clean Air Act (CAA), which would allow for the operational flexibility.
“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,” said DEP Secretary Mike Krancer. “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.”
Comments also are being accepted on a proposal to exempt some well drilling site air emission sources if the well site meets emission criteria that is stricter than rules under the CAA.
DEP in July launched its fourth study to monitor Marcellus Shale activity air quality and determine the impacts of drilling (see Shale Daily, July 25, 2012). Air aggregation drilling guidance was issued last year (see Shale Daily, Oct. 10, 2012).
The proposed exemption, which would apply to wellheads and associated storage tanks, would require an operator to control emissions more stringently and conduct leak detection on the entire wellhead. The U.S. Environmental Protection Agency last year released revised New Source Performance Standards.
“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,” said the proposal.
DEP is “doing much more by setting these limits as a line the operator cannot cross,” said Krancer. “This is an improvement in air quality protection…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.”
The industry-led Marcellus Shale Coalition (MSC) applauded the changes to the GP-5 and the proposed emissions revisions. The revisions will “further leverage technologies that continue to reduce our industry’s footprint,” said MSC President Kathryn Klaber.
Pennsylvania has more than 400 compressor stations, including older facilities that handle gas produced from conventional wells. Because gas production is not aggregated in the state, each compressor station now is considered a single source. Some conservation groups have criticized DEP on how it treats compressor stations as individual minor pollution sources, and when it groups them together with related gas facilities like wells and pipelines, to aggregate air emissions. Major pollution sources are subject to more stringent controls.
State Rep. Jesse White, who represents the heavily drilled Washington County area, said DEP’s announcement “totally ignores the real problem, which is that DEP refuses to aggregate emissions results…So if there are 10 compressors right next to one another, DEP monitors emissions from each one separately, even though the combined emissions from all 10 are coming through your kitchen window.”
DEP’s announcement Thursday coincided with a Rand Corp. study that estimated the costs in 2011 of air emissions from Marcellus Shale gas extraction. The report, which reviewed the regional air quality damages from the state’s operations, appeared to raise concerns about the long-term impacts in counties where most of the drilling now is occurring.
Rand’s researchers looked at several sources of regional air pollutants resulting from gas production: truck traffic, emissions from well sites during all phases of drilling, diesel engine use, fugitive emissions from the wellhead and emissions associated with transporting gas via compressor stations. Air quality damages in 2011 were estimated to cost the state $7.2-32 million.
The “statewide damages…were less than those estimated for each of the state’s largest coal-based power plants,” Rand said. However, in counties where gas drilling was concentrated, nitrogen oxide (NOx) emissions from all of the activities were “20-40 times higher than allowable for a single source, despite the fact that individual new gas industry facilities generally fall below the major source threshold for NOx.”
The Rand report said, “It may be hard to limit these emissions through mechanisms such as permitting restrictions, which typically do not apply to mobile and minor stationary sources. Existing regulations may therefore not be well suited for managing emissions from a substantial number of small-scale emitters. Proposals to aggregate industry sources should be carefully considered in terms of the appropriate unit of aggregation (e.g., by company, by geographic region) and any unintended consequences or perverse incentive they may create.”
Formal notices announcing DEP’s final revised GP-5, as well as the proposed rule exemptions to air quality plans, are scheduled for publication in the Feb. 2 edition of the Pennsylvania Bulletin. Comments on the proposed well site exemption rules are being accepted until March 19. Information on the final GP-5 and the proposed well site exemptions is available under the “Air” section of the DEP website or by calling (717) 787-4325.
© 2021 Natural Gas Intelligence. All rights reserved.
ISSN © 2577-9877 | ISSN © 2158-8023 |