Tracking methane leaks
On a warm fall morning, a small plane lifted off from the Denton municipal airport on a hunt for methane gas that leaks into the atmosphere.
These aerial surveys have been carried out in Texas, Colorado, Pennsylvania and elsewhere, in aircraft packed with sophisticated monitoring equipment that can distinguish methane produced by the industry from that of other sources, such as stockyards or landfills.
These results are key to figuring out what role natural gas plays in triggering climate change.
Methane is the main component of natural gas. During the first 20 years after its release, a pound of methane is some 84 times more potent in trapping sunlight than is carbon dioxide, the much longer-lived gas released when any fossil fuel is burned for power production.
The Environmental Protection Agency estimates that some 2.4 percent of the annual production of natural gas leaks into the atmosphere as methane.
Aerial surveys in several states indicate that the leak rates may be much higher than the EPA estimates. In Utah, one study indicated that the rate, at times, topped 9 percent.
But there also are signs of progress.
The process of preparing a gas well for commercial production, for example, has been a major source of vented methane. During completion, gas mixed with water flows to the surface and typically has been released into the atmosphere from an open tank. A University of Texas study found that new equipment, which next year will be required by EPA regulations, can reduce these emissions by 99 percent.
Paul Shepson, a Purdue University researcher involved in the Denton surveys, believes most of that methane can eventually be contained.
“I don’t worry so much about methane leaks. We will find the leaks and fix those problems,” Shepson said.
Even if that happens, producing power from natural gas will remain a significant contributor to climate change so long as carbon emissions continue to be released during combustion.
“The real issue is about the CO2 emissions we are committing to,” Shepson said. “The United States is reinvesting in fossil fuels as a power source, and we will keep using natural gas as long as it’s cheap.”
Hal Bernton: 206-464-2581 or firstname.lastname@example.orgAlex Krouse, Melanie Lawder and Carolyn Portner contributed research while students at Marquette University.