Satellite uncovers Ohio gas well blowout's massive methane leak

A 2018 explosion at a natural gas well owned by an ExxonMobil subsidiary emitted more methane into the atmosphere than some countries do in a year, a new study using satellite data has found.

Why it matters: It's the first time methane from an oil or gas incident has been detected and quantified using data gathered by satellite. The study shows space technology could become a key tool in detecting leaks of methane — one of the most potent greenhouse gases.

"Our work demonstrates the strength and effectiveness of routine satellite measurements in detecting and quantifying greenhouse gas emission from unpredictable events. In this specific case, the magnitude of a relatively unknown yet extremely large accidental leakage was revealed."

Details: For the study, published in the Proceedings of the National Academy of Sciences Monday, the team of scientists from the U.S. and the Netherlands used data from an orbiting satellite to identify and measure methane surging from the blowout on Feb. 15 last year at the fracking site in Belmont County owned by XTO Energy, per Reuters.

• Readings taken by the European Space Agency-launched TROPOMI instrument found in the 20 days it took to stop the uncontrolled release of natural gas, about 20 tons of methane was released per hour — twice the peak emission rate of the more widely reported 2015 blowout at SoCalGas's Aliso Canyon storage facility in California, the scientists note.
• "Assuming the observed rate reflected an average for the 20-day period, total emissions from the Ohio event would have totaled about 60,000 tons," a statement announcing the study said. "That figure is comparable to one-quarter of the entire state of Ohio's reported annual oil and gas methane emissions."

Context: Methane emissions are a "huge contributor to climate change," as report co-author Dr. Steven Hamburg, chief scientist at the Environmental Defense Fund (EDF), notes in a statement.

• Companies including ExxonMobil, the world's largest publicly traded oil producer, have set targets to cut methane emissions amid pressure from investors and the members of the public on climate change.
• The problem is source locations "are often unpredictable and can occur in out-of-the-way places all over the globe, Hamburg points out. He said the study results "show the opportunity for satellites to help see and quantify emissions no matter where they are," and that should help companies better manage emissions.

The big picture: The EDF revealed last year that studies it had organize by EDF over five years found emissions from the U.S. oil and gas sector were 60% higher than Environmental Protection Authority estimates.

• "Research has also shown that large, unpredictable events — referred to in the literature as 'super-emitters,' of which the Ohio incident was an extreme case — are responsible for a disproportionate share of total oil and gas methane emissions, " the EDF notes. But these emissions have generally not been included in EPA inventories."

What they're saying: "We deeply regret the event occurred and have instituted systematic well design and monitoring procedures to prevent it from happening again,” Exxon said in response to questions," ExxonMobil said in a statement to Bloomberg. "We are eager to learn more, and our scientists are currently reviewing the study and its assumptions."

Go deeper: New methane capture method could reduce global warming by one-sixth