Some natural gas operations in the Barnett Shale leaked more methane than previously thought, outweighing the climate benefits of the cleaner-burning fossil fuel, new studies by the Environmental Defense Fund found.
In a package of 11 studies released on Tuesday, researchers with the nonprofit group found that natural gas activity in the Barnett region may produce nearly 50 percent more methane than the U.S. Environmental Protection Agency indicated in previous estimates.
The oil and gas industry has trumpeted natural gas as a cleaner alternative to oil and coal, but environmental groups have grown increasingly worried about methane leaks associated with its production, transmission and processing. Natural gas is primarily comprised of methane, a potent greenhouse gas with a warming potential that’s 34 times as high as carbon dioxide, the research says.
In one of the studies, University of Houston researchers spent two weeks in October 2013 taking air samples from 152 sites near Fort Worth, including a dozen landfills, which naturally leak methane, as well as public roads near natural gas well pads, compressor stations and processing plants.
The majority of the well pads the researchers tested showed low emission rates for methane, but at 15 sites, the emission rates were vastly higher. At some of these sites, methane leaks resulted in emission rates worse for the climate than coal or oil production.
“Nobody had any idea how much methane was being leaked in the Barnett area,” said Robert Talbot, a University of Houston atmospheric chemistry professor who authored the paper.
Researchers weren’t allowed on site, so they couldn’t pinpoint with certainty where the leaks originated, but they did find that the air near compressor stations and processing plants had “considerably higher” methane releases than well pads, according to the study.
Workers were at times at fault for causing problems that led to leaks by failing to fix a broken valve or leaving a hatch propped open, a situation made worse with some sites left unattended for weeks, according to the report.
Talbot said he was most surprised at the size of the some of the leaks, adding that his research shows the industry could be doing a better job implementing measures to rein in methane emissions.
“Methane is an important and strong greenhouse gas,” he said. “It is contributing to global warming. The industry needs to conduct better maintenance on these facilities.”