Winter 2013

Ask the Scientist | Methane Leakage

Natural gas is often described as “clean-burning,” especially compared with coal, but I’ve read that methane can leak from natural gas operations. What are the climate implications of this leakage?

—Amy Black, Portland, ME


Steve Clemmer, director of energy research and analysis for the UCS Climate and Energy Program, answers:

 

Natural gas has a reputation as “clean-burning” due to the fact that, compared with coal, gas-fired electricity generation emits lower amounts of toxic pollutants that harm our air, water, land, and public health. In addition, heat-trapping carbon dioxide emissions from an efficient new gas-fired power plant are about 50 to 60 percent lower than those from a typical new coal-fired power plant.

However, the drilling of wells and the extraction of natural gas from those wells, along with the distribution of natural gas, result in the leakage of methane, which can trap 25 times more heat than carbon dioxide over a 100-year period. More research is needed, but preliminary studies indicate that these so-called fugitive methane emissions amount to between 1 and 9 percent of total natural gas production.

Methane leakage significantly reduces—or, at higher percentages, even negates—the potential climate advantage natural gas has over coal. One recent study, for instance, found that methane losses must be kept below 3.2 percent for natural gas power plants to have lower life-cycle emissions than coal.

While cost-effective technologies exist for reducing methane leakage, stronger policies and regulations are needed to require their deployment. And even with these technologies in place, natural gas plants are still far less attractive from a climate standpoint than cleaner, lower- (or zero-) carbon energy resources such as solar and wind power and energy efficiency.

Also in this issue of Earthwise:

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