Michael Wines writes that the "study (PDF) is the most comprehensive look to date at a contentious issue in the debate over fracking: the extent to which methane leaks during drilling and production offset the environmental benefits of the clean-burning natural gas the wells produce."
It was conducted by the University of Texas-Austin and sponsored by the Environmental Defense Fund and nine petroleum companies" and published Sept. 16 in the Proceedings of the National Academy of Sciences. "Previous E.P.A. estimates relied on engineering calculations, and other studies gathered data via aircraft flights over drilling sites", Wines notes.
The Texas study concluded that while the total amount of escaped methane from shale-gas operations was substantial — more than one million tons annually — it was probably less than the Environmental Protection Agency estimated in 2011.
One of the main reasons for the reduction of methane detected was that "[t]wo-thirds of the wells studied were capturing or controlling the methane to reduce emissions.The EPA assumed a higher percentage of methane...would be emitted", writes Wendy Koch in USA Today.
"This is good news in that it shows emissions can be controlled," says Eric Pooley, senior vice president of the Environmental Defense Fund, adding that "companies are being prodded to reduce emissions by an upcoming EPA rule — effective January 2015 — that all methane be captured when liquids are being removed after drilling", writes Koch. The liquids refers to the "copious amounts of water, sand and chemicals (that) are blasted into a well to break apart the rock and release the gas".
Fracking now produces 30 percent of all natural gas in the U.S. and is expected to reach 50 percent by 2040, writes Wines.
The University of Texas at Austin news release indicates that the study, by revealing the sources of methane leakage in the drilling process will be useful to policymakers, researchers and industry.
Recent New York Times articles written by Michael Wines on greenhouse gas emissions include: