On April 15, 2016 the Environmental Protection Agency (EPA) released a major upward revision to its estimates of total emissions of methane, a hard-hitting if short-lived greenhouse gas, in an annual inventory that the agency submits to the United Nations, according to this Washington Post report. The revisions will further up the stakes in a political battle over regulations that the agency is preparing to issue that could affect operations at thousands of oil and gas wells.

“Data on oil and gas show that methane emissions from the sector are higher than previously estimated,” said the agency in a news release announcing results of its 21st annual U.S. Greenhouse Gas inventory. “The oil and gas sector is the largest emitting-sector for methane and accounts for a third of total U.S. methane emissions.”

Prior inventories, such as last year’s report, which provided data through the year 2013, had suggested that the U.S.’s highest source of methane was ruminant animals like cattle and other livestock, rather than the oil and gas industry.

The agency revised upward total methane emissions in the U.S. for the year 2013 from 636.3 million metric tons to 721.5 million metric tons of carbon dioxide equivalents, driven in significant part by increased estimates of emissions from oil and gas operations. And the overall methane emissions number is still higher for 2014, the most recent year in the inventory, at 730.8 million metric tons.

“What EPA essentially is doing is restating the numbers using the better data that has been collected from the field” said Mark Brownstein, who heads the oil and gas program at the Environmental Defense Fund, which has focused heavily on the methane issue in recent years. “What has long been thought is that emissions in the field are higher than what had been historically reported in EPA’s emissions inventory, and now, when you use that better data, it is higher.”
The EPA revised its methane numbers upward for multiple years in its inventory. According to the agency, the average increase per year due to its revisions was 12.9 million metric tons of carbon dioxide equivalents for natural gas systems (now the largest category of methane emissions), and 20.7 million metric tons for petroleum systems.

What this means to you
In its recently released Annual U.S. Greenhouse Gas Inventory, EPA made a major upward revision to its estimates of total emissions of methane. “Data on oil and gas show that methane emissions from the sector are higher than previously estimated,” said the agency.

MIRATECH can help
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