Emissions from Natural Gas Operations Half of EPA Estimate, Survey Finds

Mark Green
Posted June 4, 2012

Methane emissions from exploration and production of natural gas, including hydraulic fracturing, are 50 percent lower than those estimated previously by EPA, according to a new survey conducted by API and America’s Natural Gas Alliance. That’s a big divergence and strongly suggests EPA needs to lower emissions estimates upon which a range of regulatory policies are based.

Why the variance? Howard Feldman, API’s director of regulatory and scientific affairs, says EPA’s 2010 greenhouse gas inventory had a smaller survey base and also overestimated the length of time and frequency of key industry processes that produce methane emissions:

• Venting of methane into the air during liquids unloading is 86 percent lower than EPA’s estimates. Liquids unloading is used to remove water and other liquids from the wellbore, to improve the flow of natural gas.
• Emissions from well re-fracturing, which is used to repair or stimulate an existing production well, to prolong production, are 72 percent lower than EPA estimates.
• Re-fracture frequency rates also are lower than EPA said. The agency estimated the rate at 10 percent of active wells, but the actual rate ranged from 0.7 percent to 2.3 percent, the API/ANGA survey found.
• The API/ANGA survey examined data on 91,000 wells operated by more than 20 companies – about 10 times the 8,800 wells used by EPA for its survey.

Feldman and Sara Banaszak, ANGA’s chief economist, discussed the new survey in a conference call with reporters. Feldman:

“The bottom line is that now, for the first time, good baseline data is available regarding the emissions generated by natural gas production in the United States. The fact that these emissions are much less than earlier, more limited estimates and the fact that operators are already working to reduce emissions from natural gas production is good news for the future of U.S. natural gas development and the game changing benefits of job creation and economic growth that will come with it.”

Feldman said the survey’s findings have significant policy ramifications:

“This emissions information is critically important because it allows oil and gas companies, citizens, and regulators to gauge the industry’s impact on the environment and allows companies to measure continued efforts to reduce their environmental footprint.”

The results come as some opponents of natural gas and hydraulic fracturing campaign to block both. Feldman:

“[The survey shows] the emphasis on natural gas is good for the country, good for jobs and good for consumers.”