Researchers at Purdue University and the Environmental Defense Fund have concluded in a recent study that natural gas power plants release 21-120 times more methane than earlier estimates. Published in the journal Environmental Science and Technology, the study also found that for oil refineries, emission rates were 11-90 times more than initial estimates. Natural gas, long touted as a cleaner and more climate-friendly alternative to burning coal, is obtained in the U.S. mostly via the controversial horizontal drilling method known as hydraulic fracturing ("fracking").The scientists measured air emissions at three natural gas-fired power plants and three refineries in Utah, Indiana, and Illinois using Purdue's flying chemistry lab, the Airborne Laboratory for Atmospheric Research (ALAR). They compared their results to data from the U.S. Environmental Protection Agency's (EPA) Greenhouse Gas Reporting Program.<snip>"[Methane is] a better fuel all around as long as you don't spill it," Paul Shepson, an atmospheric chemistry professor at Purdue, said in a press release. "But it doesn't take much methane leakage to ruin your whole day if you care about climate change."The researchers were careful to differentiate between emissions related to natural gas combustion versus leakage, with the latter found to be the primary source of methane emissions in this small, preliminary study. Previous estimates of methane emissions were reported to the EPA from the facilities themselves and were restricted to what came out of the smokestack, which means they excluded leaks from equipment such as steam turbines and compressors.The study was done as part of EDF's ongoing series of studies measuring methane emissions and leakage throughout the U.S. natural gas supply chain. EDF said in its press release that the Purdue scientists plan to follow up with research at additional oil refineries and power plants. Purdue stated in a press release that support for the research also came from the National Science Foundation (NSF).