HOUSTON -- Natural gas switching seems to be the topic du jour when it comes to mitigating climate change. Whether it’s the Environmental Protection Agency (EPA) estimating cutting carbon emissions by 30% by switching coal plants to natural gas, or Budweiser switching its diesel fleet to CNG, everyone seems to be talking about switching the switch. Natural gas is purportedly cleaner-burning than coal, so these switches mean big wins for the environment, right?

Not necessarily, according to David Lyon, a research analyst for the Environmental Defense Fund (EDF). Methane is a particularly potent greenhouse gas when first released, and the natural gas and petroleum industry accounts for about 30% of methane emissions in the U.S. Over the first 20 years of its release, methane’s cumulative effects are 84x that of carbon dioxide. Because methane breaks down faster than carbon dioxide in the atmosphere, its cumulative effects go down to 28x over 100 years.

Lyon, speaking at a shale conference in late October at Rice University’s James A. Baker Institute for Public Policy, emphasized the importance of targeting fugitive emissions (simply put, leaks) for both the climate and companies to benefit. He cited a 2011 study that found that at 7.9% methane leakage, natural gas would be no better than coal for power generation.

“A coal power plant, at a 2.7% lower leak rate, you see immediate climate benefits,” he added, citing a more recent study. “But if the leakage is any more than that, due to the short-term climate impacts of methane, it takes sometimes several hundred years before you start seeing actual benefits.”

The EPA estimates 1.3% methane leakage nationally. That is equivalent to the greenhouse-gas emissions of 117 million cars, 146 coal power plants over 20 years, the annual gas consumption of 5.1 million homes, or gas carried by 127 LNG tankers.

“This is a value commodity that’s being lost, $1.7 to $6.2 billion of lost revenue,” Lyon said. “So we don’t want to just get methane leakage down to these threshold rates, we want to get it as low as possible.”

But leaks are sneaky because the entire natural gas supply chain is a methane source, Lyon said. Emissions can be found across the supply chain, including production, processing, transmission and storage and distribution. In addition, data isn’t always reliable. Flyover studies can provide an accurate picture of methane in the atmosphere over a large area, but can’t necessarily distinguish where the gas is coming from. They can also be biased high, Lyon said.

Meanwhile direct measurements get accurate data from the source, but data is limited to the few sites that are sampled, resulting in incomplete data and research that is biased low.

So the EDF embarked on its own series of 16 studies to better understand where methane comes from across the entire supply chain and to determine what the actual leakage rate might be. The studies include flyovers and direct measurements, including one study that incorporated both methods at the same time.

One study already published, which relied on direct measurements at almost 200 well sites, found that total sector emissions were in line with the EPA’s estimates but that emissions from well completions were lower. That is probably because two-thirds of completions used controls (such as “green completions”) that reduced emissions by 99%. “Companies are actually starting to control these emissions,” Lyon said, adding that new federal regulations requiring the use of green completions don’t go into effect until January 2015. However, the researchers found that pneumatic controller and equipment leaks were higher than EPA estimates. The study was led by the University of Texas but relied on partners such as Anadarko Petroleum, Pioneer Natural Resources, ExxonMobil and Encana for access to sites and technical advice.

Another study at the other end of the supply chain (and the one with perhaps the biggest “wow factor”) outfitted Google mapping cars with methane sensors to detect, locate and measure methane leaks in Boston, Indianapolis, and on Staten Island in New York. That study found that the cities with older infrastructure (Boston and Staten Island) had numerous leaks throughout the city. In Indianapolis, where infrastructure is newer and pipes are made of plastic instead of cast iron, there were only five leaks.

“If you replace cast iron with plastic, you can drastically reduce emissions,” Lyon said.

Other studies, including ones on gathering and processing, super emitters, transmission and storage, and natural gas-fueled vehicles, are on the way. The hope is that industry can learn from the studies to get emissions as low as possible.

“To get all of the benefits of natural gas development, we really need to minimize these risks,” Lyon said. “If you don’t, producers lose the social license to operate, and you’ll have the public trying to obstruct new development. And so it’s really in everybody’s best interest to minimize these risks.”

Converting to natural gas might not be as easy as switching a switch, but if done correctly, the climate and the industry could both win.

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