But every day, pipelines across California leak tons of the same gas — methane — into the air. And the total amount collectively leaked each year likely exceeds the vast volume of methane spewed from the Aliso Canyon blowout near Porter Ranch, according to one state estimate.
Most of the leaks are small, even tiny. But many have been seeping for years, deemed too insignificant by the utility companies to warrant an immediate fix.
And since methane has 25 times the heat-trapping power of carbon dioxide when released into the atmosphere, it boosts the global warming emissions that California is working hard to cut.
“There are all these small events, mini-Aliso Canyons, everywhere, and unfortunately you might need to dig up the streets to get them,” said Timothy O’Connor, director of the California Climate Initiative at the Environmental Defense Fund nonprofit group. “But there are solutions out there.”
California officials and utility executives are trying to get a sense of how big a problem those leaks may be. Climate change is only one reason. As the 2010 San Bruno disaster demonstrated, gas leaks sometimes explode, with deadly results.
The Aliso Canyon leak didn’t kill anyone, but it did seriously disrupt the lives of 4,645 households.
L.A. blowout halted
Southern California Gas Co. reported finding natural gas spewing out of control from a well in the company’s underground gas storage field north of the San Fernando Valley on Oct. 23. At a rate of up to 1,200 tons per day, the gas continued flowing from the well until last Thursday, when the company finally brought it to at least a temporary halt.Methane, the main component of natural gas, has no scent. But the smell of other chemicals in the spreading gas cloud overwhelmed residents of the nearby Porter Ranch neighborhood and, they say, triggered intense headaches, nausea and nosebleeds. Thousands relocated to temporary housing, paid for by the company.
Estimates of the amount of methane the Aliso Canyon well pumped into the atmosphere range from 80,000 metric tons to more than 95,000. In terms of global warming potential, those volumes are equal to 2 million to 2.38 million tons of carbon dioxide, or roughly the amount produced by as many as 500,000 cars in a year.
For more than three months, that one well became the single biggest source of greenhouse gas emissions in California. But substantially more methane may leak from the state’s sprawling network of natural gas pipelines in a typical year.
Small part of emissions
The California Air Resources Board, for example, estimates that the network lost enough methane in 2013 to equal the global warming power of 3.81 million tons of carbon dioxide.It’s a small piece of California’s overall emissions. The board, which runs many of California’s global warming programs, estimates that California produced 459.28 million tons of carbon dioxide equivalent in 2013, the most recent year for which data are available. Pipeline gas leaks, in other words, represent just under 1 percent of the state’s emissions. Cars and trucks, in contrast, account for 33.8 percent of the total.
And yet, experts say the leaks also represent one source of emissions that can be largely eliminated, if never stamped out entirely.
“Is it possible? Yes, I think so,” said Jim Howe, senior director for regulatory affairs at Pacific Gas and Electric Co.’s gas operations. The utility has been forced to re-examine all of its gas operations, including leak detection, since one of its pipelines beneath San Bruno exploded on Sept. 9, 2010, killing eight people.
“Our focus is safety, but it helps with global warming too,” Howe said.
With 42,000 miles of gas distribution lines and another 6,750 miles of larger transmission lines, PG&E uses aircraft and foot patrols to hunt for leaks.
And starting in 2012, the company has increasingly relied on a new technology developed by Santa Clara’s Picarro Inc. to spot leaks undetectable by other means. Mounted on cars, Picarro’s detectors are about 1,000 times more sensitive than older technologies.
“We’re a lot more comfortable that it’s really picking up the vast majority — if not all of — what’s out there,” Howe said.
Pipes being replaced
Perhaps just as important, PG&E has been replacing older, leak-prone pipes, for example taking out of service all remaining 800 miles of cast-iron pipes.In 2010, Howe said, the company had a repair backlog of about 12,000 gas leaks categorized as grade one or two, meaning they either posed a hazard or could be expected to pose a hazard in the future. By the end of 2015, the backlog had been cut to 90, he said.
State officials have also focused more intently on gas leaks in the aftermath of San Bruno. A 2014 law directed the California Public Utilities Commission and the utility companies to develop a system for regularly reporting gas leaks and tracking the amount of gas lost, both to protect public safety and fight global warming.
It remains a work in progress. Although the utilities have been submitting leak estimates to the commission, they haven’t used the same methods. The commission is now trying to standardize the process.
Progress made
O’Connor’s organization, which has made cutting gas leaks one of its key efforts nationwide, believes California utilities are still undercounting the problem. For example, one update PG&E provided the commission estimated just 11,193 metric tons of methane leaked in 2014, the most recent year available. That equals 279,825 tons of carbon dioxide equivalent — just 7 percent of the state’s estimated total methane leaks.Still, O’Connor is encouraged by the attention finding, fixing and preventing gas leaks has been getting across the country, even before Aliso Canyon.
“This is an emission that we can limit, at a relatively low cost, for pennies on the dollar,” he said. “And it’s wasted gas that goes into the atmosphere, when it should be sold.”
©2016 the San Francisco Chronicle Distributed by Tribune Content Agency, LLC.
