Recent measurements from a climate pollution-sensing airplane show oil and gas sites are leaking methane at four times the rate reported to federal regulators.
The Environmental Defense Fund’s MethaneAIR system measured data from about 70 percent of the country’s oil and gas regions over the course of 30 flights by planes outfitted with special cameras.
Researchers used the measurements to calculate methane intensity–the rate of methane that’s not captured during production–at 1.6% across 12 oil-producing basins in the U.S. The data were compared with the Environmental Protection Agency’s 2020 methane emissions inventory, which estimates a lower rate of loss, based on industry reporting.
EDF’s images and modeling show the basins could be releasing 7.5 million metric tons of methane per year. EDF says that’s enough gas to meet the energy needs of more than half of U.S. homes annually.
Methane is the main component of natural gas and can trap a lot of heat in the atmosphere, contributing to global warming.
EDF lead senior scientist Ritesh Gautam said the methane intensity is lowest in the Haynesville basin, which spans the Texas-Louisiana border, and in the Appalachian basin, which covers Pennsylvania and West Virginia.
“The loss rates from these two places are about 1%. That’s still five times higher than the industry targets,” Gautam said.
Companies accounting for more than 40 percent of global oil production–including Shell, Exxon, and EQT–have signed on to a goal to bring methane emissions to “near zero” by 2030.
They define “near zero” as 0.2% loss rate or lower.
Mark Omara, a senior scientist at EDF, said the 0.9% loss rate in the Appalachian basin may be because gas is its main product, not oil.
“Operators want to transport that gas to the market, want to sell that. And so there is every incentive to ensure that those operations are efficient,” Omara said.
In oil-dominant basins, gas can be seen as a byproduct.
Though emissions rates are relatively low in Pennsylvania, researchers said the basin is still among the highest total emitters in the country, behind the Permian in Texas.
A Clean Air Task Force study from June found emissions of methane and carbon dioxide increased 4% in the Appalachian basin between 2015-2022, even though emissions dropped nationally.
Evan Sherwin, a research scientist at Lawrence Berkeley National Laboratory, conducts his own studies of methane emissions and has previously evaluated the accuracy of MethaneAIR.
A study of Sherwin’s published in Nature in March found a methane intensity of .75% in the Appalachian basin.
He said the similar findings are a good sign.
“Overall, I think it’s very encouraging to see how closely these numbers align with some of the other recent estimates we’ve seen for the same region,” Sherwin said.
Gautam said the sensors on MethaneAIR have identified around 400 high-emitting sources, but individual sites don’t account for the majority of total emissions.
“They are a collection of emissions that are not really detected as individual plumes. They might be coming from individual facilities, but they’re emitting at very, very low rates,” he said. “But in the aggregate, they add up significantly.”
Omara said the data from MethaneAIR could be used to help hold governments and companies accountable to their emissions reduction targets.
“Methane is a critical climate warming pollutant, whose mitigation today is really needed in order to be able to reduce the harmful impacts of climate warming. To be able to do that, we need comprehensive data on where these emissions are located and how much is being emitted and how those emissions are changing over time,” Omara said.
Lost methane can be expensive, for companies and for people’s health and safety.
Sherwin’s study calculated an annual loss of about $1 billion in commercial gas value and a yearly social cost of $9.3 billion due to a warmer world’s influence on agricultural productivity, negative health effects, and property damage from more intense natural disasters.
Sherwin said there are more tools available now to measure methane loss than there were even five years ago.
“I do think that methane is very much a solvable problem, certainly methane emissions from oil and natural gas systems,” Sherwin said.