The oil and gas industry is cheering a pair of studies that show that less methane than estimated is leaking during the fracking process, which it says validates the climate change benefits of using natural gas to generate electricity.
Tracking methane that escapes during fracking is central to the debate on whether burning natural gas to produce power yields fewer greenhouse gas emissions than coal. While natural gas is half as carbon dense as coal, methane is at least 20 times more potent at trapping heat. Environmentalists say a leakage rate of 3 percent could erase the climate benefits of natural gas.
The joint Environmental Defense Fund and University of Texas-Austin studies showed that the leakage rate from fracking wells falls below that mark. Overall, those leaks account for 0.38 percent of the lifecycle of natural gas emissions. That’s less than what the same research team found in September 2013 is below the Environmental Protection Agency’s estimate of 1.5 percent.
“That means the study is in line with EPA’s estimate for methane leakage, which (at about 1.5 percent) is well below the threshold for natural gas to retain environmental and climate benefits,” Katie Brown, a spokeswoman with industry-backed group Energy In Depth, said in an email.
The studies, published Tuesday in the journal Environmental Science and Technology, come as the Obama administration is set to announce an interagency strategy to reduce methane emissions that could include new regulations on the oil and gas sector. Methane is the largest unregulated greenhouse gas in the U.S., accounting for 9 percent of total emissions.
Liz Purchia, a spokeswoman for the EPA, said the agency couldn’t comment specifically on the EDF and UT-Austin studies. But Purchia told the Washington Examiner that the agency has “gotten significant feedback on where opportunities and challenges lie on where leaks are happening, where the sector is moving, what it’ll take to capture leaks, what are cost-effect strategies at the state or voluntary level, etc. We’ll be putting out a strategy soon that looks at policies available currently and tools we have to continue the discussion.”
The American Petroleum Institute said the studies showed that the industry is making strides through voluntary measures, and noted oil and gas companies have an incentive to reduce leaks to ensure natural gas gets to the market instead of into the air. The lobby group has pressed the White House to avoid issuing new regulations for methane, which it contends could raise costs and freeze fracking, a drilling method that injects a high-pressure cocktail of water, sand and chemicals into tight-rock formations to tap hydrocarbons buried deep underground.
“Study after study shows that industry-led efforts to reduce emissions through investments in new technologies and equipment are paying off,” said Howard Feldman, director of regulatory and scientific affairs at API.
Measuring methane emissions from fracking is a fairly new discipline. Fracking proliferated rapidly as technological advancements in the practice helped drive an American energy boom that has seen the U.S. become the world’s top natural gas producer and second-leading oil producer.
Differing approaches to testing emissions have yielded varying results.
The EDF and UT-Austin studies used a bottom-up accounting by measuring emissions from individual components used during the fracking process. The researchers said that method is considered a more accurate gauge that a top-down measurement of atmospheric concentrations of methane, as the former can better test whether certain wells contribute more emissions than others. Top-down studies, which are generally less expensive, have tended to find higher concentrations of methane in the atmosphere.
In both studies, a small fraction of the wells accounted for a bulk of the emissions from the two processes evaluated. Researchers discovered 19 percent of the pneumatic devices, which are used to open and close valves, comprised 95 percent of the emissions. For wells with liquid unloadings, which clear fluids to boost production, one-fifth of the wells accounted for between 65 and 83 percent of emissions.
“To put this in perspective, over the past several decades, 10 percent of the cars on the road have been responsible for the majority of automotive exhaust pollution,” said David Allen, chemical engineering professor at the Cockrell School and principal investigator for the study. “Similarly, a small group of sources within these two categories are responsible for the vast majority of pneumatic and unloading emissions at natural gas production sites.”
The studies assessed 377 pneumatic devices and 107 wells with liquid unloadings. Those two fracking components account for roughly 40 percent of total methane leakage during fracking, according to the studies.
Researchers found that the EPA undercounted the amount of emissions from pneumatic devices by 17 percent. Emissions from liquid unloadings were marginally lower than EPA estimates.
Geography also played a role. Emissions from pneumatic devices were lower in the Rocky Mountains than in the Gulf Coast. But wells in the Rockies, which vent more frequently, contributed about half the emissions from unloadings.
