A 2018 blowout at a natural gas well in Belmont County, Ohio, released more methane into the atmosphere than several European countries do in a year.
A study published in December in the Proceedings of the National Academy of Sciences used measurements from the Tropospheric Monitoring Instrument (TROPOMI) satellite to document the methane released during the 20-day event. It was undertaken by SRON Netherlands Institute for Space Research and the Environmental Defense Fund.
Methane is the second largest contributor to global warming after carbon dioxide and emissions from the fossil fuel industry are one of the major sources of atmospheric methane.
“Gas leakages due to accidents in the oil and gas sector can release large amounts of methane within short periods of time. Although these emissions are very challenging to monitor, satellite measurement platforms offer a promising approach by regularly scanning the entire globe,” the study states. Accidental emissions often go underreported in emissions inventories, but the satellite technology can help determine their significance.
In the 2018 blowout at a well owned by Exxon Mobile Corp. subsidiary XTO Energy, the researchers determined that an estimated 120 tons of methane per hour was released over the 20 days before the well was brought under control. The emissions rate was roughly double that of the largest known gas leak in the U.S., which occurred in 2015 in California.
TROPOMI observed emissions from the Ohio blowout during the 13th day, which was likely not the peak rate. “Assuming the detected emission represents the average rate for the 20-day blowout period, we find the total methane emission from the well blowout is comparable to one-quarter of the entire state of Ohio’s reported annual oil and natural gas methane emission,” the study states.
“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,” the study continues.
Natural gas companies have instituted voluntary methane emission reduction programs, with a number of them participating in the EPA’s Natural Gas Star and Methane Challenge.
Having the ability to monitor natural gas emergencies using satellite data can help scientists better estimate the amount of methane going into the atmosphere and help natural gas producers be transparent about methane releases.