Gas stoves leak climate-warming methane even when they're off

Sandy Khabbazeh makes a pot of Syrian coffee on a stove in Oakland, N.J., on Nov. 22, 2015.

Your natural gas cooking stove may leak climate-warming methane even when it is turned off, warns a new Stanford University study.

That's important because methane is a much more potent greenhouse gas than even carbon dioxide, though it doesn't linger in the atmosphere nearly as long.

Stanford scientists measured methane released from gas cooking stoves in 53 California homes. They examined how much methane is leaked each time you turn the knob in that second before the gas lights on fire. They also measured how much unburned methane is released during cooking. And unlike most previous studies, they measured how much methane is released when the stove is off.

Gas stoves emit pollution into your house and are connected to a production and supply system that leaks the powerful greenhouse gas methane during drilling, fracking, processing and transport.

The gas utility industry sees the campaign against gas stoves as an existential threat. Utilities and their trade group, the American Gas Association (AGA), are trying to find cleaner replacements, such as "renewable natural gas" from agriculture, and using hydrogen produced with renewable energy.

Investigations

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The AGA says it has not had time to fully review the Stanford study. Still, the trade group says its members are working to reduce emissions across their networks by doing things like replacing older pipes that leak. "Natural gas distribution system emissions have declined 69% since 1990," says Karen Harbert, the AGA's president and CEO.

Utilities also are getting laws passed to preserve their business. According to the Natural Resources Defense Council, 20 states now have laws on the books that prevent cities from banning gas hookups in new buildings. Such bans have become a trend in places like Seattle, Berkeley, Calif., and New York City, as local governments try to meet their increasingly aggressive climate targets.

One defender of natural gas utilities, Frank Maisano, with the energy law and lobbying firm Bracewell, said the methane leakage issue had not emerged in previous testing, which generally focused on indoor air quality. "Certainly, it is new to hear that emissions occur on stoves that are off. That requires further investigation," Maisano said.

There's an easy way to limit methane leaks

Replacing a gas stove with an electric one is not an option for people who can't afford it or for renters. But Jackson says there's still something you can do and all it takes is a wrench.

"Pull the stove out from the wall and tighten the connectors to the stove and to the nearby pipes," he says. That should reduce the leaks. The AGA recommends that only licensed professionals do maintenance on gas lines and appliances.

Still, Jackson is among those concluding that the only way to ensure there are no leaks is to switch to an electric stove. He says research has convinced him it's time to do that.