AUSTIN, Texas — A University of Texas study has found that hydraulic fracturing, or “fracking,” produces fewer greenhouse gas emissions than had been thought.
Researchers from the University of Texas’ Cockrell School of Engineering, working with two environmental testing firms, tested 190 sites around the country where fracking is used to extract gas from rock layers deep below ground.
The Environmental Defense Fund and nine energy companies sponsored the study, which was released Monday. The energy firms, including Shell, Southwestern Energy and a subsidiary of ExxonMobil, provided the researchers with unprecedented access to their fracking sites to gather samples and data.
The researchers found that equipment the companies use at fracking wells captures 99 percent of the methane gas emitted there — preventing it from being released into and harming the air.
However, the researchers also found that methane emissions from valves used in fracking, called pneumatic devices, are 30 percent or more higher than estimates from the Environmental Protection Agency.
They concluded that, overall, methane emissions from natural gas production are in line with recent EPA estimates.
The study, published in Proceedings of the National Academy of Sciences, was led by UT chemical engineering professor David Allen and the results were reviewed by a scientific advisory panel.
The Environmental Defense Fund is planning more studies to research the effects of different steps in the fracking process, said Drew Nelson, the organization’s manager of special projects.
“There are very important conversations taking place around the value of natural gas as a source of energy,” said Curtis Smith, a spokesman for Shell, which took part in the study. “Now we have actual data so that we can better focus future efforts on what will achieve real improvements to operations and benefit the environment.”
Other groups suggested Monday that there was an undue amount of industry influence on the study.
“The industry sponsorship of the study raises conflict-of-interest questions,” Kevin Connor of the Public Accountability Initiative said in a statement Monday. “While the sponsors are disclosed in the body of the article, no information is offered about how conflicts of interest were managed to assure the independence of the research.”
Allen, the lead researcher, is a journal editor for the American Chemical Society and has been a consultant for several companies, including ExxonMobil, according to a statement from UT.
Allen said in a conference call Monday that the nine energy companies offered access to their sites and did not direct or interfere with researchers as they collected samples.
Many questions have surrounded the levels of methane gas that are released during fracking. If not captured, methane can be highly damaging to the atmosphere and is a leading cause of climate change, environmentalists and scientists have said.
“There has been a raging debate about (the level of) emissions associated with natural gas production,” said Mark Brownstein, associate vice president and chief counsel of the U.S. Climate and Energy Program at the Environmental Defense Fund. “Universally, people have been talking about the need to get actual data. This is actual data.”
“Emissions from controls on valves and from leaks at the production site are higher than people expected, so there are opportunities to make changes and reduce emissions,” Brownstein said. “We are beginning to get some insights into what needs to happen to ensure that natural gas production is as clean as it can be.” During fracking, a high-pressure water mixture is directed at rock layers deep below ground, creating new pathways to release natural gas.
Fracking has been the principal reason that historically volatile natural gas prices have stayed steady in recent years.
Texas has been one of the biggest of the natural-gas boom states. Proponents say the gas can offer a reliable energy supply at low prices, as well as environmental benefits because it emits about half the carbon of coal when used in power production.
Still, concerns persist about whether fracking pollutes groundwater. There have also been conflicting views about how much methane fracking releases into the atmosphere.
During the yearlong study, the UT researchers looked at fracking sites scattered throughout the U.S., including the Gulf Coast, Rocky Mountain and Appalachian regions.