ALBUQUERQUE, New Mexico -- A large portion of a Delaware-sized methane cloud hovering over the Four Corners region of southwestern U.S. is coming from a coal mine and several natural gas operations, according to a new study led by scientists from NASA’s Jet Propulsion Laboratory.
Researchers from the California Institute of Technology, the National Oceanic and Atmospheric Administration and the University of Michigan also participated.
The scientists conducted an airborne campaign in the Four Corners region during April 2015 over a 1,200 square mile area with the next-generation airborne near-infrared and thermal infrared imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. The airborne measurements were supplemented by measurements by ground crews.
The study identifies about 250 individual sources—including the San Juan coal mine and gas wells, storage tanks, pipelines, and processing plants—appear to account for about half of all methane emissions in the area. Of that, about 50% of emissions is coming from just 25 individual sources, meaning two dozen points of emission are responsible for about one-fourth of all the methane spewing into the atmosphere in the Four Corners, according to a news report in the Albuquerque Journal.
The study authors suggest that airborne observing strategy and its ability to locate previously unknown point sources in real time provides an efficient and effective method to identify and mitigate major emissions contributors over a wide geographic area. Further illustration of this potential is demonstrated with two detected, confirmed, and repaired pipeline leaks during the campaign.
Industry representatives said more research is needed, since the study only focused on about half of the region’s methane emissions. “It addressed a limited set of methane sources,” said New Mexico Oil and Gas Association president Steve Henke in a prepared statement. “It has been known by the states and tribes in the Four Corners that natural methane seeps occur throughout the area from the Fruitland Formation outcrop. Also the topography of the area traps air and causes methane to build up over time, whether from human or natural sources.”
The study comes amidst debate over new Environmental Protection Agency rules released in May, plus forthcoming Bureau of Land Management regulations, that require industry operators to cease venting natural gas into the air, repair leaky infrastructure and monitor their assets for methane emissions.