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Massive California Gas Leak is an Example of Wider Methane Problem

Natural gas is often touted as a “green” fuel that produces about half as much carbon dioxide pollution as coal when burned to generate electricity.

But new research suggests that so much gas escapes from thousands of leaks in pipes under city streets, as well as from industrial and drilling sites across the country, that the benefit of natural gas to the climate may be much less than people think.

“Natural gas is primarily made up of methane, and methane is a very powerful greenhouse gas pollutant,” said Mark Brownstein, vice president for climate and energy at the Environmental Defense Fund.  “Methane is many times more powerful than carbon dioxide. In fact, in the near term, it is more than 80 times more effective in trapping the Earth’s heat than carbon dioxide.  And what that means is that relatively small amounts of carbon dioxide escaping into the atmosphere are a big problem for the climate.”

A spectacular example erupted outside Los Angeles, in an area called Aliso Canyon.  There, on October 23, natural gas started leaking from an underground storage well owned by the Southern California Gas Company.   It turned into one of the biggest leaks ever recorded – like the BP oil spill, but into the sky.

As of yesterday morning, 95 million tons of methane had escaped – creating as much pollution as cars burning about 900,000 gallons of gasoline, according to Environmental Defense Fund.

Governor Jerry Brown declared a state of emergency. Emergency crews are struggling to plug the leak. Thousands of residents of the upscale Porter Ranch community were evacuated, some after complaining of headaches, nausea and nosebleeds.

The incident is unique in its size.  But in another way, it was common.  Researchers have found tens of thousands of much smaller leaks in gas lines across the country, Brownstein said. Methane also seeps from numerous gas drilling, collection, and processing sites.

“The oil and gas industry each year puts about seven million tons of methane into the atmosphere,” Brownstein said. “And that has the same impact on the climate over 20 years as pollution from 165 coal fired power plants.  ”

Scientists working with Environmental Defense Fund teamed up with Google to use cars driving around cities taking street-level photographs for Google Earth maps. The cars were equipped with methane sensors to detect gas pipeline leaks.  The gas-sniffing cars have not yet visited Baltimore or Washington, D.C. But the motorized monitors detected one natural gas leak for every mile driven in Boston and New York; and about one leak every three miles in Chicago.

So how many gas leaks are out there?

I asked this question to Dr. Anthony J. Marchese, a professor of mechanical engineering at Colorado State University who is also an associate dean at the university and director of the Engines and Energy Conversion Laboratory. 

“How many?” he laughed.  “There are probably an infinite amount of leaks of various shapes and sizes. And some of them are built into the system, where we -- on purpose -- leak out little tiny amounts.  We use high pressure natural gas to actuate valves and even to start some engines.”

Marchese said that the U.S. Environmental Protection Agency (EPA) currently assumes that about 1.3 percent of natural gas is lost in leaks.  If about three percent leaked out, Marchese said, natural gas would be worse for the climate than coal.  The reality, taking into account the new studies, is that probably more like two percent leaks out, Marchese estimated. That would make natural gas worse than most people think it is, but still better than coal.

The good news, Marchese added, is that many of these leaks can be avoided by industry without any radical changes. Industry can simply modernize its systems to make them more efficient.  Better maintenance and monitoring will also reduce emissions.

Other researchers have offered different conclusions.  Cornell University Professor Dr. Robert Howarth, for example, argues that the problem is worse than Marchese suggests, and that natural gas is actually worse for the climate than coal, because of all the leaks in the system.

“Using the new, best available data and a 20-year time period for comparing the warming potential of methane to carbon dioxide, the conclusion stands that both shale gas and conventional natural gas have a larger greenhouse gas (footprint) than do coal or oil,” Howarth wrote in a 2014 article in the journal Energy Science and Engineering. The article was headlined, “A Bridge to Nowhere: Methane Emissions and the Greenhouse Gas Footprint of Natural Gas.”

The gas industry disputes Howarth’s conclusions and the work of Environmental Defense Fund (EDF).

“EDF chooses arbitrarily to use a 20-year timeframe to make the impact of methane seem more dramatic than it is,” wrote David Quast, a director of Energy in Depth, a publication of the Independent Petroleum Association of America, in a recent blog article.  “The standard in greenhouse gas analyses – including the federal Greenhouse Gas Inventory – is based on a 100-year time frame, in which methane is 25 times more potent than carbon dioxide.”

EPA is now finalizing regulations that will, for the first time, directly regulate methane emissions from future oil and gas facilities.  But these new rules will not clamp down on existing sites, like the Aliso Canyon gas storage facility in California that produced the massive leak.  

So environmental advocates argue that more federal regulations will be needed if the greenhouse gas footprint of natural gas is to be reduced significantly.

Tom Pelton, a national award-winning environmental journalist, has hosted "The Environment in Focus" since 2007. He also works as director of communications for the Environmental Integrity Project, a non-profit organization dedicated to holding polluters and governments accountable to protect public health. From 1997 until 2008, he was a journalist for The Baltimore Sun, where he was twice named one of the best environmental reporters in America by the Society of Environmental Journalists.