US oil, gas system methane leaks larger than EPA estimates: Study

An oil drill near a construction site for homes and office buildings on Feb 5, 2015 in Midland, Texas.
An oil drill near a construction site for homes and office buildings on Feb 5, 2015 in Midland, Texas. PHOTO: AFP

WASHINGTON (REUTERS) - US oil and gas drilling and related operations give off much more of the powerful greenhouse gas methane than the federal government estimates, wasting about US$20 billion (S$27 billion) of fuel a year, scientists said on Thursday (June 21).

Methane, the main component of natural gas, is colourless and odorless. It is a major force in short-term global warming because it has more than 80 times the warming potential of carbon dioxide in the first 20 years after it escapes into the atmosphere.

In high concentrations it can also lead to formations of smog, which is linked to heart and lung damage.

The amount of methane leaked from US oil and gas wells and related infrastructure in 2015 equalled about 2.3 per cent of the country's overall natural gas output, a study led by the Environmental Defense Fund advocacy group said.

That was much more than the 1.4 percent the Environmental Protection Agency estimated for 2015 in a report last year.

Due to the tens of billions of dollars' worth of fuel that vanishes in the air, some energy companies are expected to cut down on emissions using better monitoring equipment in drones and vehicles.

"This is a solvable problem because you are losing product that you could sell," said Steven Hamburg, the EDF's chief scientist and a co-author of the study. "But the entire industry has to take action to stop the problem," he added.

Once leaks are detected, stopping them becomes a matter of routine maintenance that cuts down on well breakdowns, which are more expensive to fix, he said.

The study, integrating five years of research by scientists from 15 universities and institutions, including Stanford, Harvard and Purdue, said it was the most comprehensive look ever at fugitive methane emissions from US energy development.

The research was published in the journal Science.

While President Donald Trump's administration has been trying to roll back methane rules on energy operations set under former President Barack Obama, the EPA's underestimation had nothing to do with politics, said Hamburg.

Still, federal regulations are needed to address the emissions, because voluntary actions by companies are not enough, he said.

"The data is saying the problem is worse than we thought, the need for regulation is thus that much greater," Hamburg said.

The EPA likely underestimates the emissions because it seeks permission from oil and gas operators to take measurements and workers may avoid errors or fix problems when measurement teams arrive, the study said.

The study relied on both top-down measurements, such as aircraft observations, and bottom-down measurements made directly at, or downwind of energy facilities.

An EPA spokeswoman said the agency will review the study.

Most of the emissions come from malfunctioning well pads that are not fixed because the leaks are not detected, the study said. Leaks can be found at both young and mature wells and at fracking and conventional wells. The malfunctioning wells were"largely absent from EPA's inventory," Hamburg said.

The study did not consider leaks from local distribution and power plants that burn natural gas or chemical plants that use it to make products. But scientists say those leaks are significant.