Natural gas consists primarily of methane, a global warming pollutant far more powerful than carbon dioxide. During the production, storage and transportation of natural gas, some escapes into the atmosphere. Even relatively small methane leaks can cause electricity generated from burning natural gas to be worse for the climate than electricity from coal. Methane leakage on the order of 3.2 percent to 3.4 percent of natural gas produced makes it a dirtier fuel than coal.
The latest study, accepted for publication in the journal Environmental Science & Technology, was conducted by researchers at Carnegie Mellon University and the National Oceanic and Atmospheric Administration. The four authors used global methane and ethane measurements over three decades to estimate how much comes from fugitive emissions from natural gas production. Their conclusion, obtained through two different modeling approaches, is that fugitive emissions from natural gas production since 2000 have ranged from 2 to 4 percent, though they may have been as high as 5 percent from 2006 to 2011.*
That means electricity generated from natural gas is either a bit better for the climate than electricity from coal, or a bit worse. Either way, natural gas is not a clear winner for the environment. Therefore, the idea that natural gas can be a “bridge fuel” to a cleaner future doesn’t make sense. Accepting the argument that natural gas should be a bridge fuel leads to the conclusion that society would be well-served by investing in more natural gas-fired power plants, natural gas-powered vehicles, and new transmission and distribution infrastructure. However, methane leakage means that these investments won’t provide meaningful climate benefits. Instead, they will divert money and effort from truly clean technologies (i.e., wind, solar, geothermal and energy efficiency) that can help us slash global warming pollution now and in the years to come.
* High fugitive emissions don’t occur just from fracking. The global data suggest that all natural gas production is problematic. From 1985 to 1999—notably before the boom in high-volume hydraulic fracturing—the researchers estimate that fugitive emissions could have been as high as 9.3 percent.
Associate Director and Senior Policy Analyst, Frontier Group
Elizabeth Ridlington is associate director and senior policy analyst with Frontier Group. She focuses primarily on global warming, toxics, health care and clean vehicles, and has written dozens of reports on these and other subjects. Elizabeth graduated with honors from Harvard with a degree in government. She joined Frontier Group in 2002. She lives in Northern California with her husband and son.