Studies: A few natural gas facilities generate big portion of pollution

FORT COLLINS – Much of the natural-gas pollution from gas processing and transmission facilities comes from a few facilities, according to two new studies that researchers say provide the most comprehensive look yet at the matter.

Colorado State University and Carnegie Melon University researchers published two separate studies in the journal of Environmental Science & Technology: one looking at methane pollution from gas transmission and storage facilities and another study looking at the same kind of emissions from gas gathering and processing facilities.

Methane is a potent greenhouse gas that can trap heat in the atmosphere more effectively than carbon dioxide. Nearly 30 percent of methane emissions in the U.S. in 2012 came from oil and natural-gas development, according to the Environmental Protection Agency.

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The studies include measurements taken from Northern Colorado and the Western Slope, as well as in 12 other states.

Scientists completed measurements last April, before Colorado’s new air quality rules began to take effect. The new rules require leak detection from tanks, pipelines and other drilling and production processes, using devices such as infrared cameras.

“Unfortunately, most of our field measurement occurred before those rules were in effect,” said Anthony Marchese, a CSU professor of mechanical engineering who led the study. “It would be very interesting to redo the study a year from now and see if we see some measured differences.”

The team took measurements of methane pollution from 45 transmission and storage facilities nationwide. Two of the sites emitted 40 percent of the pollution of the facilities, or as much methane as the other 43 facilities combined, according to researchers.

Faulty valves and equipment may have caused the higher emissions at the two sites, said Allen Robinson, a mechanical engineering professor at Carnegie Mellon, though researchers declined to identify individual facilities.

Researchers also took air samples at 114 gathering stations and 16 processing plants. They found that 30 percent of the gathering facilities accounted for nearly 80 percent of the methane emissions measured.

The CSU study is one of 16 organized by the Environmental Defense Fund and industry companies to better quantify the amount of methane escaping into the atmosphere from the natural gas supply chain. It was sponsored by EDF, Access Midstream, Anadarko Petroleum Corp., Hess Corp., Southwestern Energy Co. and Williams. The companies provided financial support for the study and access to facilities. DCP Midstream provided access to one of its processing plants.

Before the studies by the universities, much of the scientific data on methane pollution came from studies conducted in the 1990s, researchers said.