The U.S. Environmental Protection Agency this week reduced its estimate of how much methane is released during oil and natural gas production in a move that drew both praise and criticism from the energy industry.
Oklahoma City-based Devon Energy Corp. praised the new findings, but said they did not go far enough.
“The announcement is really good news for the country. We're glad to see it,” said Bill Whitsitt, Devon's vice president of regulatory affairs. “But there is still more refinement to be done. We're confident the EPA will soon say they have still been overestimating by a significant degree.”
The new EPA report said industry efforts to reduce emissions have resulted in an average annual decrease of 41.6 million metric tons of methane emissions from 1990 through 2010, down about 20 percent from previous estimates.
Methane is the main ingredient in natural gas.
While burned methane produces fewer emissions than coal or oil, methane released into the atmosphere is considered to be a greenhouse gas about 20 times more potent than carbon dioxide.
Whitsitt agreed that oil and natural gas producers have improved their processes and reduced emissions, but he said this week's EPA report revises data in only two of 33 categories.
The EPA still is overestimating the amount of methane released during hydraulic fracturing, or fracking, and well completion, Whitsitt said.
“We met with the EPA last week and continue to provide them with additional data,” he said. “Hopefully in the not-to-distant future, you will see an additional announcement out of the EPA.”
While there is disagreement as to how much methane is released through oil and natural gas operations, producers and regulators both show the industry improving.
Besides the environmental benefits, producers also benefit economically from reducing methane leaks.
“That's our product,” Chesapeake Energy Corp. spokesman Michael Kehs said. “We want to bring our product to market for the benefit of our customers and our shareholders.”
Kehs pointed out that Chesapeake and other producers have installed more efficient valves, pumps, controllers and other equipment and use infrared cameras and other monitors to detect and reduce methane emissions.
One example of a more efficient and environmentally friendly upgrade is vapor recovery equipment, which captures methane released from oil as it waits in storage tanks before being transported to a refinery.
Without it, the methane typically is vented out of the storage tanks to avoid pressure buildup.
The vapor recovery equipment attaches to the tanks, where it collects the associated methane and pumps it into a pipeline for processing and delivery.
While the technology has been available for decades, it has gained widespread use within the past five years, said Tyson Curtis, vice president of operations at Oklahoma City-based Flogistix, which manufactures and sells vapor recovery equipment.
“The process eliminates a lot of safety concerns on location where you have raw natural gas present. It eliminates that issue by keeping it contained and in the pipeline,” Curtis said. “It also has an economic advantage because instead of emitting or flaring the gas, the producers are able to sell it just like they would gas from a standard well.”
The EPA last fall tightened its emissions regulations, slashing the amount of allowable emissions to 6 tons per facility, down from 40 tons previously.
Curtis said the producers have benefited from the regulations because proceeds from the additional natural gas they collect and sell can pay for the equipment and generate a profit.
“This is one of the few cases where the environmental regulation is economically beneficial,” he said. “Originally the regulation drove demand for the product. But once installed, the economics took over and producers were able to see it is an economic advantage to install the system in most cases.”