The oil/natural gas industry remains the largest source of U.S. methane emissions, according to the latest survey from the Environmental Protection Agency (EPA), which was released Friday. Oil/gas emissions are now pegged at being 34% higher than previous EPA estimates.

Measuring emissions from 1990 through 2014, the EPA calculated that the oil/gas sector emits 9.8 million metric tons (mmt) of pollution into the atmosphere annually.

EPA data shows that greenhouse gas emissions (GHG) in 2014 totaled 6,870 mmt of carbon dioxide (CO2) equivalents, and the U.S. emissions increased by 1% from 2013. “Recent trends can be attributed to multiple factors driving increased fuel use including year-to-year changes in the prevailing weather and an increase in miles traveled by nonroad vehicles,” an EPA official said.

On the plus side, GHG emissions in 2014 were 9% below 2005 levels. However, methane from oil/gas totaled 244.2 mmt in 2014, compared 240.3 mmt in 2005, according to the EPA survey.

The previous EPA survey last year showed methane emissions from natural gas production had fallen about 38% since 2005, but emissions from processing increased by about 38% since that year, and rose about 11% from gas transmission and storage sources (see Daily GPI, April 16, 2015). At the time, EPA said methane emissions from hydraulically fractured gas wells had declined about 79% since 2005.

The American Gas Association (AGA) and the American Petroleum Institute (API) concentrated on different aspects of the EPA survey data, with API expressing concerns about new methodology used in the latest GHG inventory.

“EPA has made a significant change in its inventory methodology, and we believe it is seriously flawed,” said Kyle Isakower, API vice president for regulatory/economic policy. “Industry led efforts to reduce emissions through investments in new technologies and equipment are paying off.”

AGA said that the EPA’s latest statistics show “emissions from local distribution systems decreased by 74%, 1990-2014, following a substantial downward revision for the sector.” EPA cited gas industry efforts to replace old distribution piping as a major reason for the decline, the Washington, DC-based trade group said.

Environmental Defense Fund”s (EDF) Mark Brownstein said the EPA data indicates that “the oil and gas methane problem is much larger than government or industry was telling us,” so the federal agency is now making necessary corrections.

Technology advances are available to address the problem, Brownstein said.

“Major reductions in methane pollution are possible with some simple technologies and systematic efforts to find and fix leaks. Some companies are already going in the right direction.”

What EDF wants are more national standards to “ensure that all companies play by the same set of rules.” Under EPA’s revised data calculations, emissions overall in 2014 were up by 1.6% over the previous year, and 11% from 2010, according to EDF.

EPA discussed all the recalculations and improvements it made in the latest inventory, noting that for natural gas systems that resulted in an increase in average annual emissions of 12.9 mmt CO2 equivalent. For petroleum systems the result was an average annual increase in emissions was 20.7 mmt CO2 equivalent. Most of the 10 sectors measured had increases, but there were exceptions, such as landfills, which decreased 6.4 mmt CO2 equivalent.