Large methane plumes at a Chevron oil and gas project off Western Australian’ northwest coast have sparked a warning from the UN.
The UN Environment Program issued the warning to Chevron after a satellite detected high levels of methane on five consecutive flyovers from November to August.
The plumes were purportedly coming from Chevron’s Gorgon liquefied natural gas plant on Barrow Island, off the Pilbara coast, and the latest expulsion was equivalent to burning 110 tonnes of coal.
Chevron says satellite readings “have a wide range of uncertainty”.
“Satellite observations capture a single moment in time and have a wide range of uncertainty,” a Chevron spokesperson said.
“We use them alongside aerial surveys, operating data and on-site checks to enhance how we understand and manage methane emissions.”
Chevron is “seeking further clarification” on the satellite data.
“We understand the importance of methane management as well as the community’s expectations on this issue, and our Australian facilities are designed, operated and maintained to manage methane emissions,” the spokesperson said.
“We report emissions from our facilities in line with Australian regulatory requirements.”
Those required emissions reports are published by the government once a year – companies are required to submit their emissions figures by October 31 each year.
Methane is about 80-times worse for global warming than carbon dioxide over a 20-year span and accounts for about 25 per cent of global warming, UN figures show.
The UN agency uses 30 satellites operated by non-profit Carbon Monitor to detect methane.
Australia accounts for two of the world’s top-35 methane emitters; both out of venting shafts at east coast metallurgical coalmines.
One Mexican and two Turkmenistani oil and gas facilities are the world’s top three methane polluters, and landfills across Europe and Asia account for five of the top 10.
The Australian coal mine that is 24th worst in the world emitted 28,557 tonnes last year at an average of 3.26 tonnes per hour.
The satellite readings say methane was coming from the Chevron plant at a rate of 7.8 tonnes per hour in August.