The amount of methane leaking into the atmosphere from natural gas sites and contributing to global warming might be highly underestimated, according to a researcher who happens to have invented the technology used to measure leaks. In a new paper published today, Touché Howard notes an issue with the EPA-approved Bacharach Hi-Flow Sampler, used in monitoring natural gas facilities, means the device could fail to record leaks up to a hundred times worse than estimated, reports the New York Times. The two-sensor device works like this: One sensor records low levels of methane emissions until they become high enough that a second high-level sensor takes over. The problem, as identified by Howard, is that the device, unless frequently recalibrated, can crash during the switch so that the high-level sensor records no measure of the methane leak.
"There is no way to determine the magnitude" of the problem without independent measurement when the leak occurs, Howard says. He cites a landmark 2013 study that measured methane at 150 natural gas production sites across the US using the Bacharach Hi-Flow Sampler, noting methane emissions could be far higher than anyone really knows. An author of that study is standing by his work, claiming "we didn’t see any evidence that we were missing any large numbers." Natural gas companies often use the sampler to report their methane emissions to the EPA. "If Howard's right, we'll need to review other emission estimates used in EPA inventories," a methane expert tells InsideClimate News. "We need to sort this out as quickly as possible." An EPA rep says it will review Howard's study while device maker Bacharach says it will update its manuals to recommend frequent recalibration.