Aliso Canyon methane leak 6. (credit:
Earthworks / Flickr)
A massive natural gas leak at a storage facility in Southern
California was caused by microbial corrosion of well equipment,
according to a new independent report from analysis firm Blade
Energy Partners. The report blames the storage facility owner,
Southern California Gas (SoCalGas) for failing to conduct follow-up
inspections of equipment, despite knowing about 60 smaller leaks at
the facility that had occurred since the 1970s.
The final leak—which spewed 109,000 metric tons of methane
into the air over five months between 2015 and 2016—was the
biggest methane leak in US history. (A larger loss of methane
occurred in 2004 in Texas, but a corresponding fire immediately
combusted the methane into carbon dioxide.) But the California leak
at the Aliso Canyon Natural Gas Storage Field was particularly
devastating because methane, unfortunately, is a far more potent
greenhouse gas than carbon dioxide.
The new report (PDF) was commissioned three years earlier to
find the root cause of the leak. According to a press release from
the California Public Utilities Commission (CPUC), Blade Energy
Partners found that the leak came from a seven-inch outer well
casing which had corroded due to exposure to microbes from
groundwater. The natural gas storage facility at Aliso Canyon is
made up of dozens of vast underground caverns which were previously
filled with oil before they were pumped and emptied decades ago.
Since then, the caverns have been used to store natural gas to
supply the Southern California area.
Source: FS – All – Science – News
Massive 2015 natural gas leak caused by microbial corrosion, report says