Handful of ‘Super-Emitters’ Produce Most Oil and Gas Methane

A large-scale aerial survey of U.S. oil and gas installations finds that a small percentage of locations are responsible for most of the methane leaking into the atmosphere from the industry’s operations.

The Environmental Defense Fund (EDF) hired a leak detection company to fly helicopters equipped with methane-detecting infrared cameras past more than 8,000 well pads in seven U.S. basins. “The proportion of sites with high-emitting sources was 4% nationally,” the researchers report in a forthcoming study in the journal Environmental Science and Technology, “but ranged from 1% in the Powder River (Wyoming) to 14% in the Bakken (North Dakota).”

Nine out of ten “super-emitting” leaks were from tank vents and hatches, EDF noted, “demonstrating that tank emission control systems commonly underperform.”

Methane is a shorter-lived but much more potent greenhouse gas than carbon dioxide. Depending on how the calculation is done, its global warming impact is anywhere from 24 to 72 times greater than CO2’s. The oil and gas industry in the United States is estimated to release more than nine million tons of methane into the atmosphere each year.

The EDF research “also confirmed what other studies have shown,” lead author David Lyon writes on the organization’s blog. “Super-emitting sources are nearly impossible to predict. They can happen anywhere, anytime as a result of malfunctioning equipment that goes unattended and sloppy mistakes in the field.

“Rather than trying to guess where these super polluters will occur, it is clear from the study that regularly checking oil and gas facilities for leaky equipment is a more effective way to identify both high-polluting sources, as well as sources which may be individually smaller but are collectively significant.”

Global methane emissions could be reduced 40% with existing technologies, the EDF estimates, a result that would “have the same near-term climate benefit as eliminating 1,000 coal-fired power plants.”