Over the next two weeks, they returned twice and found large amounts of the powerful greenhouse gas each time. It was just one of many persistent methane emitters discovered by an aerial survey conducted by the Environmental Defense Fund over the largest U.S. oil field in July and August.
The invisible leak was later calculated at more than a ton per hour, with a short-term impact on the atmosphere equivalent to about 47,000 idling cars.
Halting methane leaks has become one of the most important fronts in the fight against climate change, and companies across the U.S. energy industry have been pledging to curb their emissions of the gas. But the study released Thursday shows a shocking amount of pollution continues.
Methane is the chief component of natural gas and packs more than 80 times the planet-warming power of carbon dioxide over a 20-year period. It often escapes undetected by companies that produce and transport natural gas, and in some cases methane is intentionally vented to prevent equipment failure.
The results of the flyovers don’t appear to show much progress compared to a similar survey conducted in 2019, said David Lyon, a senior scientist at EDF. “Emissions are still very high, so there’s still a lot of opportunities for companies to reduce.”
EDF found emissions at a total of 533 different locations, including 149 persistent ones, where plumes were spotted in the same place on at least two different days. Energy Transfer and Targa Resources Corp., both Texas-based pipeline operators, were among those with the highest numbers of persistent sources at 11 and 16, respectively.
In all, emissions from persistent locations made up about 45% of all methane EDF detected over the course of the survey. EOG Resources Inc. had the highest number of persistent locations among oil and gas producers, with eight sites that had a plume on more than one day during the survey.
An Energy Transfer spokeswoman said she couldn’t speak to the accuracy of the survey data. The company complies with an air permit in place at the compressor station found emitting methane and regularly monitors the facility for emissions, she said.
A representative for EOG said the company believes its methane-emissions performance in the Permian “compares favorably against others in the industry” and that it would review the data for accuracy. Targa didn’t respond to a request for comment.
The EDF survey used an airplane operated by Carbon Mapper, a nonprofit that partners with NASA’s Jet Propulsion Laboratory. It’s able to see only the largest plumes of gas, sometimes referred to as “super-emitters.”
The best way for companies to eliminate these super-emitters is to perform their own regular inspections, Lyon said. Some companies conduct their own aerial surveys to hunt for leaks, while others use stationary monitors at their sites.
U.S. Environmental Protection Agency rules require companies to inspect oil and gas wells regularly for leaks, but those rules apply only to new facilities. The agency is currently drafting rules that would apply to older facilities, but it hasn’t yet said whether those rules would extend to low-producing oil and gas wells. Many industry groups oppose methane regulations on low producers, arguing that inspection costs could make these wells uneconomic.
EDF said its findings bolster the case for including low-producing wells, which made up about one-tenth of the emissions sources it identified.
When it comes to cracking down on methane emissions, oil and gas industry groups said this month that they actually favor direct regulation over a proposed fee that Democrats have introduced as a way to pay for their $3.5 trillion spending plan. A coalition of trade groups and local chambers of commerce called the measure “punitive” and said taxing methane emissions from oil and gas facilities would threaten Americans’ access to cheap energy.
Any impact from such a fee on drillers’ bottom line would depend heavily on how methane emissions are measured, Citigroup Inc. analysts wrote in a note to clients this week. That’s because methane estimates based on satellite images and aerial surveys tend to show far higher counts than what companies self-report to U.S. regulators.