April 17, 2012

Climate-Energy Nexus and the Benefits of Natural Gas

A new study from the Proceedings of the National Academy of Sciences offers an important reminder about the climate-energy nexus that has been largely missing from the energy conversation as of late.

There have been a lot of studies done recently on how America’s boon in domestic natural gas and oil production made possible by hydraulic fracturing can improve American energy security – specifically by reducing U.S. reliance on energy imports. Although this does little in the near term to assuage concerns about high oil prices given that oil prices are set by the international market, it does help mollify concerns about assured access to energy if the United States is increasingly relying on domestic production to supply its demand. Moreover, some studies have specifically noted that America’s abundance of natural gas could displace coal as the dominant feedstock in electricity generation, which could dramatically reduce U.S. greenhouse gas (GHG) emissions since natural gas produces about half as many GHG emissions as coal.

Yet this optimism about natural gas and its climate benefits may be premature, according to a recent study by the Proceedings of the National Academy of Sciences (PNAS).

Recent reports in the scientific literature and popular press have produced confusion about the climate implications of natural gas,” the study reports. “On the one hand, a shift to natural gas is promoted as climate mitigation because it has lower carbon per unit energy than coal or oil. On the other hand, methane (CH4), the prime constituent of natural gas, is itself a more potent GHGthan carbon dioxide (CO2); CH4 leakage from the production, transportation and use of natural gas can offset benefits from fuel-switching.” The authors go on to explain that other recent studies have found that displacing coal with natural gas could potentially be worse for climate change in the short term given the challenges with methane leakage. The study cites a recent paper that “calculated upstream leakage rates for shale gas to be so large as to imply higher lifecycle GHG emissions from natural gas than from coal.”

The PNAS findings provide some support to the Environmental Protection Agency’s (EPA) efforts to promote new rules for the natural gas industry. The PNAS results “underscore the appeal of rules about to be finalized at the EPA, which would require natural gas producers to prevent leaks from wells, pipelines, storage tanks and other infrastructure,” according to an editorial in the Sunday Washington Post. “The rules are designed to reduce the release of volatile organic compounds that form dangerous smog, but the EPA estimates that they would also result in the collection of 3.4 million tons of methane annually, a quarter of current methane emissions from the sector.”

Although the findings are not entirely conclusive – and further study should be done – the PNAS results reinforce an important concept about energy and climate change: that the two must be viewed as two sides of the same coin. As the United States gives greater attention to efforts to bolster its energy security, U.S. policymakers must be reminded that any effort to make the United States more energy secure should also produce positive benefits for the climate, not exacerbate it. While exploitation of harder to reach domestic oil and natural gas reserves could in the short term bolster U.S. domestic energy production, curb our reliance on imports of foreign energy supplies and reduce the U.S. current account deficit, these solutions may worsen climate change over the long term and present the United States with a new set of challenges that we will need to adapt to.