Natural Gas May Not Be 'Clean' Energy Source
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Natural gas may not be as clean an energy source as advertised. That is the finding of a study released this week by professors at Cornell University. They suggest that significant amounts of methane are escaping into the atmosphere during certain kinds of gas production. Methane is a potent greenhouse gas that contributes to global warming.
But the natural gas industry claims the study is flawed, as NPR's Joel Rose reports.
JOEL ROSE: Lately, natural gas has built a reputation as the cleaner fossil fuel, an idea fueled in part by the industry itself.
(Soundbite of a commercial)
Unidentified Woman: I'm very excited about natural gas drilling. It's a clean gas. It's highly abundant in the United States.
ROSE: That's an ad produced by America's Natural Gas Alliance, an industry trade group. The alliance provides funding support for NPR.
But now a study from Cornell University is shedding doubt on those claims. The researchers agree that natural gas produces fewer greenhouse gases and toxins than coal when burned, but lead author Robert Howarth says you also have to count how much natural gas or methane escapes from new, unconventional production techniques.
Mr. ROBERT HOWARTH (Ecologist): So when you throw in this methane leakage and look at the entire greenhouse gas footprint, our conclusion is that the natural gas actually has a larger greenhouse gas footprint than even coal. It's not a clean fuel at all in that regard.
ROSE: To understand the Cornell study, it helps to know how the industry extracts natural gas that's trapped way below the surface, in shale formations, a process known as hydraulic fracturing or fracking.
Engineers inject water and chemicals into the ground, then wait for those liquids to come back up the well along with natural gas. The Cornell study says up to eight percent of that gas escapes into the atmosphere, much higher than previous estimates from the Environmental Protection Agency and others.
Russell Jones at the American Petroleum Institute says Howarth's study is flawed.
Mr. RUSSELL JONES (American Petroleum Institute): He doesn't provide any relevant data. His data is either really old or irrelevant.
ROSE: For his part, Cornell's Howarth admits that he doesn't have as much data on methane leakage as he'd like, but he says that's because the industry is suing the EPA to block such data from leaking out.
What's not in dispute is that natural gas reserves in the U.S. are abundant. Daniel Weiss is a senior fellow at the Center for American Progress, a self-described progressive think-tank in Washington. He says the methane leakage issue needs further study, but he thinks it can be solved.
Mr. DANIEL WEISS (Center for American Progress): We've got the technology to capture and sell the methane, let's make sure it's used. Natural gas can still be an important bridge fuel to a clean-energy future where our energy use is dominated by truly renewable energy sources.
ROSE: But Cornell's Robert Howarth says technologies to capture methane leakage aren't widely used. He thinks natural gas is a bridge fuel to nowhere.
Mr. HOWARTH: That concept came about because there was this misconception that the greenhouse gas footprint of shale gas was significantly lower than coal. And until we're proven wrong by better science, I think it would be a tragic mistake to view this as a transitional fuel.
ROSE: Howarth hopes the study, published this week in the journal Climatic Change Letters, will influence the public policy debate about gas development. For the moment, New York state has a moratorium on new gas wells while regulators study the air and water pollution impacts of fracking. But the practice is already widely used in Pennsylvania, West Virginia and other states in the South and West.
Joel Rose, NPR News, New York.
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