Greenhouse gas emissions from hydraulic fracturing, or fracking, are “significantly lower” than EPA estimates, according to a new study from the University of Texas and the Environmental Defense Fund.
The study, which measured methane emissions during completion operations for hydraulically fractured wells, found emissions were 97 percent lower than 2011 national estimates released by the EPA in April.
Several oil and gas companies supported the study including Anadarko Petroleum Corporation, BG Group, Chevron, Encana Oil & Gas, Pioneer Natural Resources Company, Shell, Southwestern Energy, Talisman Energy USA and XTO Energy, an Exxon Mobil subsidiary.
The year-long study is based on emissions measurements made directly at 190 production sites throughout the US, with access provided by nine participating energy companies. A team of researchers from UT Austin’s Cockrell School of Engineering and environmental testing firms URS and Aerodyne Research completed the measurements.
The sampling was designed to be representative of company operations in the Gulf Coast, Mid-Continent, Rocky Mountain and Appalachian regions. Measurements of active equipment at 150 production sites with 489 wells, 27 well completion flowbacks, nine well unloadings and four well workovers were included in the study. The types of sources measured account for two-thirds of methane emissions that occur during natural gas production, as estimated in the most recent national greenhouse gas inventory.
The researchers found that the majority of fracking sites sampled had equipment in place that reduces methane emissions by 99 percent.
The analysis also found that emissions from certain types of pneumatic devices are 30 percent to several times higher than current EPA estimates for this equipment; combined, emissions from pneumatics and equipment leaks account for about 40 percent of estimated national emissions of methane from natural gas production.
Total methane emissions from natural gas production — from all sources measured in the study — were comparable to the most recent EPA estimates, researchers say.
The analysis shows that when producers use equipment to capture or control emissions, methane can be “dramatically reduced,” says Mark Brownstein, associate vice president and chief counsel of the Environmental Defense Fund’s US Climate and Energy Program. However, the study also shows that certain methane emissions are larger than previously thought, indicating that companies have further opportunities to reduce emissions, Brownstein says.