Aliso Canyon Natural Gas Well Blowout Was The Largest Methane Leak In US History, According To Study

Published on February 29th, 2016 | by

February 29th, 2016 by

The recent natural gas well blowout in Aliso Canyon, California, was the largest methane leak in US history, according to new research from the University of California–Davis, the National Oceanic and Atmospheric Administration, and others.

During the period of activity — at least, October 23, 2015, through February 11, 2016 — more than 100,000 tons of methane escaped from the well. During the peak of the leak, enough methane was escaping from the well everyday to “fill a balloon the size of the Rose Bowl.”


 

Given the fact that methane is a powerful greenhouse gas, the recent leak means that California will likely have trouble meeting greenhouse gas emissions targets for the year, according to the researchers.

“Our results show how failures of natural gas infrastructure can significantly impact greenhouse gas control efforts,” stated NOAA’s Tom Ryerson, co-lead scientist on the study.

Apparently, researcher and pilot Stephen Conley of Scientific Aviation and UC Davis had to double check if his gear was malfunctioning when gathering the first readings back in November because the readings were so high.

“It became obvious that there wasn’t anything wrong with the instruments,” he noted. “This was just a huge event.”

Here’s more from a new press release:

At the time, Conley and his specially equipped plane were working with UC Davis on a California Energy Commission project searching for pipeline methane leaks. The state agency asked him to overfly the area around the breached SoCalGas well.

Conley teamed with Ryerson, who pioneered techniques for assessing oil spills with airborne chemical sampling during the 2010 Deepwater Horizon oil spill and the 2012 Elgin rig blowout in the North Sea. They assembled a group of researchers from the University of California, Irvine; the California Energy Commission; and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, many of whom had previously collaborated on regional air quality projects.

The team’s measurements confirmed that high concentrations of methane and ethane were surging from the breached well into the densely populated San Fernando Valley. The analysis found that at its peak, the blowout doubled the rate of methane emissions from the entire Los Angeles basin and temporarily created the largest known human-caused point source of methane in the United States, twice as large as the next-largest source, an Alabama coal mine.

Eventually, more than 5,726 families were evacuated and Governor Jerry Brown declared a state of emergency Total emissions during the 112-day event were equal to one-quarter of the annual methane pollution from all other sources in the Los Angeles basin combined. The disaster’s impact on climate will be equivalent to the annual greenhouse gas emissions from over half a million passenger cars.

“The methane concentrations were extraordinarily high, the highest we’ve seen in ambient samples,” stated Blake, who has measured air pollutants across the globe for more than 30 years. “We also detected other volatile organic compounds.”

The new study was published in the journal Science.


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