LA's Methane Gas Leak Was One of the Biggest Environmental Disasters in US History

[FLPanhandle]

http://gizmodo.com/las-methane-gas-leak-was-one-of-the-biggest-environment-1760788080

A week after the ruptured natural gas well near Porter Ranch, California was officially sealed, we have the full damage report. And it reveals that this was easily one of the largest environmental disasters in US history.

All told, the leak released 97,100 metric tons of heat-trapping methane over 112 days, equivalent to the annual greenhouse gas emissions of over half a million cars, according to a scientific paper published today in Science.

“This is by far the biggest [methane leak] I’ve ever seen,” said Don Blake, an atmospheric scientist at UC Irvine and a co-author on the Porter Ranch gas leak study.

For those who’ve been following the saga, which began when a natural gas storage well in Aliso Canyon erupted on October 23, 2015, the total amount of methane reported in the new study may look familiar. In fact, it’s just a shade higher than the final reading on a real-time ticker the Environmental Defense Fund has maintained since December.

Both numbers are drawn from the same underlying source: a series of thirteen research aircraft flights conducted between November 7, 2015, and February 13, 2016, two days after the leak was plugged. Also included in the new study is data on the rate of methane leakage over time, and an analysis of potential carcinogens released from the well, including benzene, toluene, and xylene. (Levels of these compounds, although enhanced in the methane plume, were still quite low.)
“I thought there must be something wrong with the instruments”

When Stephen Conley, a scientific aviation specialist at the University of California, Davis, was asked by the California Energy Commission to conduct a flyover of Aliso Canyon on November 7, Southern California Gas Company had already reported a well leak, but nobody had any idea how big it was. That’s why, when Conley’s air sampling instruments read methane concentrations of 50 to 60 parts per million (ppm), he figured it must be a mistake. The background concentration of methane in the air is typically around 2 ppm.

“I thought there must be something wrong with the instruments,” Conley told Gizmodo. “Luckily, we had two instruments on board that both measure methane. When I got on the ground and compared the two, I realized it wasn’t an accident.”
LA's Methane Gas Leak Was One of the Biggest Environmental Disasters in US History
Infrared footage of the natural gas plume erupting from Aliso Canyon, via EDF

Once the sheer size of the leak became apparent, a state response took off. Conley began conducting regular flights over the town of Porter Ranch, tracking methane concentrations in the gas leak’s plume as it blew from the north. “Essentially we constructed a curtain downwind of the site and measured all the gas flying through that curtain,” he said.

At its peak in November, a staggering 60 metric tons of methane spewed out of the ruptured well every hour. In early December, the leak began to slow down, as SoCalGas started drawing natural gas out of the leaky well and sending it to homes to relieve pressure.

Still, the leak continued to spew methane until February 11, when a two-month drilling operation finally reached the well some 8,500 feet beneath the ground, and injected hydraulic fluids to temporarily plug it. Several days later, the leak was permanently sealed with cement.

A small amount of methane continues to seep out of the ground—either from gases trapped in the soil, the wellhead, or an imperfect seal—and Conley says he’ll continue flying over the site until the flow rate stabilizes.

[mrdmk]

1. Guess who gets to pay for that accident?

Hint: It is not the company or the shareholders...