...Methane, the primary component of natural gas, (click here) is a powerful greenhouse gas--25 times stronger than carbon dioxide (CO2) over a 100-year time horizon and 72 times stronger over a 20-year horizon. Though methane represents only about 10-12 percent of all U.S. greenhouse gas emissions, it is a significant driver of short-term warming, and reducing methane emissions can help slow the rise in global temperatures.
While proponents of natural gas often tout its “green” credentials—combustion of natural gas emits roughly one-half the CO2 of coal combustion—this is not the whole story. When it is extracted from the well, natural gas is composed of roughly 83 percent methane, after processing and through the point of delivery, it is more than 90 percent methane. Producing, processing, and transporting of natural gas can release some of this methane into the atmosphere. Accidental methane leaks and routine venting--which together, make up fugitive methane emissions--reduce the comparative climate advantage of natural gas for electricity generation. Plus, at current estimated leakage rates, fugitive emissions actually make compressed natural gas a questionable choice for fuel-switching in cars and trucks....
