Another study published this week in the journal Geophysical Research: Atmospheres identified more than 200 hotspots for methane leaks throughout the Los Angeles region, just miles from the Porter Ranch blowout.
Advertisement
Attorneys representing the county, the gas company and Porter Ranch residents gave oral arguments this morning. Processed natural gas is composed primarily of methane, a powerful greenhouse gas, and ethane. 0002 percent of total methane emissions. “But on a city level, it’s huge”. That is equivalent to annual volume of emissions from 600,000 cars.
But the capping of the well doesn’t mean Southern California’s methane problem is solved. The study found that the United States could be responsible for between 30% and 60% of the global growth of methane emissions since 2002 due to a 30% spike in domestic methane emissions across the country over that time period.
“If you stuck a balloon over the leak, it would fill up the Rose Bowl”, said Conley.
The paper’s authors said that these estimates could be refined in coming months using different sampling methods, but they noted that their “rapid-response airborne chemical sampling method” was useful to provide a quick, independent, and accurate measure of the leak rate. That is similar to Conley’s measurements. He has a pilot’s license and flies a two-seat airplane, one of only a handful in the nation equipped with sophisticated gear for taking atmospheric measurements.
After the leak was discovered, Southern California Gas Company, which is owned and operated by Sempra Utilities, tried seven times to stop the high-pressure natural gas from escaping into the atmosphere.
Commission officials soon asked Conley to start flying over the Aliso Canyon site.
“Our results show how failures of natural gas infrastructure can significantly impact greenhouse gas control efforts”, said NOAA’s Tom Ryerson, co-lead scientist on the study, in a statement.
Conley says he couldn’t believe how high the methane readings were when he first flew through the plume.
Another option is for SoCal Gas to measure the volume of gas left in its storage facility and compare that with the amount there before the leak, adjusting for volumes injected and withdrawn since the emissions began.
Natural gas has always been considered the cleaner fossil fuel. But, she said, she is unsure if the US can meet its greenhouse gas emissions reductions goals with the natural gas infrastructure now in place. In 2009, the Environmental Protection Agency found a leakage rate of 2.4 percent from natural gas transmission lines.
In a separate filing Wednesday, the utility companies said, “Establishing a methodology for measuring emissions from such unusual events is challenging and unique, as ARB [the California Air Resources Board] has recently recognized in discussing the limitations of the aerial surveys over the Aliso Canyon storage facility”.
“They continue to say they are going to make it right, they are going to mitigate the emissions”, said Timothy O’Connor, director of the Environmental Defense Fund’s California oil and gas program.
Advertisement
Gabrielle Petron, an atmospheric scientist at NOAA and the University of Denver who studies pollution near oil and gas operations, said the Aliso Canyon leak and others like it shouldn’t distract the USA from focusing on reducing carbon dioxide emissions. The Obama administration has a target of cutting methane emissions from the oil and gas sector between 40% and 45% from 2012 levels by 2025.
