Tapping methane produced from decaying garbage in landfills to generate electricity was among California's earliest experiments in renewable energy.
But in order to comply with a new regional rule to cut another pollutant — the one that often leaves Southern California blanketed in a layer of smog — a Riverside County landfill has decided to shut down its generators and will simply flare the methane, sending tons of carbon dioxide into the atmosphere.
The decision reflects a clash of environmental goals and regulations — and demonstrates some of the difficult choices confronting California as it pushes ahead on reducing greenhouse gases. Environmental policies on water use and storage, for example, can reduce the amount of hydro power the state will be able to generate.
The regulations are further complicated because climate change programs are largely run by the state's Air Resources Board, while smog and toxic rules are largely determined by regional agencies like the South Coast Air Quality Management District.
California now has 81 landfills producing electricity, leading the nation. California landfill and composting account for about 9 million tons of greenhouse gas emissions every year, according to state estimates. According to the U.S. Environmental Protection Agency, "reducing methane emissions from municipal solid waste landfills is one of the best ways to achieve a near-term beneficial impact in mitigating global climate change."
Waste Management's power plant in Riverside, at the El Sobrante Landfill, generates 3,840 kilowatts of power around the clock — unlike the intermittent output of wind and solar systems. The plant has been operating for about a decade, annually producing enough electricity for a few thousand homes.
The problem began after the AQMD issued a complex 39-page rule requiring that by no later than Jan. 1, landfill methane power plant emissions meet the same standard as other types of engines that use geologic natural gas.
The rule was intended to reduce emissions of oxides of nitrogen, or NOx — considered to be an indirect greenhouse gas since it can affect ozone, but one that is not at the center of climate change efforts.
"Reducing NOx limits is the key to our clean-air puzzle," said Sam Atwood, a spokesman for the air district. He acknowledged that flaring is less than ideal, since it produces carbon dioxide even as it reduces NOx.
Waste Management officials said that they considered upgrading its equipment at El Sobrante but faced "high cost to stay in compliance" with the new NOx standards.
"It doesn't pencil out for us," said Lily Quiroa, a company spokeswoman. "Ultra-low emissions landfill gas flare … is an approved practice and fully compliant with AQMD regulatory standards."
The engine emission rule appears to be more stringent than the one applying to flaring gas. But pollution regulations are just one problem facing the landfill gas industry.
Another Waste Management landfill in Simi Valley is also halting its power generation because it can not compete against other renewable power. Solar and wind energy can underbid the landfill power on the daily electricity auction market, in part because they are more heavily subsidized.
The new regulations and the state's competitive electricity markets are threatening the future of the landfill gas industry, said Evan Williams, president of Cambrian Energy, a Los Angeles-based company that has set up dozens of landfill power plants across the nation.
"It is going to happen with a lot of them," he said.
And the environmental battle against methane is only going to get tougher.
The main constituent in natural gas, methane is a powerful agent of climate change, and emissions must be cut by at least 40% over the next 14 years under the newly enacted SB 1383. Sponsored by Sen. Ricardo Lara (D-Bell Gardens), the legislation will require that a lot of methane that now escapes in transmission systems at dairies and landfills be tapped and somehow put to use.
"We can be much smarter," Lara said, referring to landfill operations and reductions of organic waste.
George Minter, vice president for external affairs and environmental strategies at Southern California Gas, expects the state to undergo a massive shift to renewable natural gas, probably under a government mandate.
But how the gas will get transported, how it will be cleaned up for domestic use and how it will be subsidized to make it competitive with cheap geologic gas is still being worked out. Massive federal subsidies for the use of renewable natural gas are making it competitive with cheap geologic gas for transportation fuel.
"We increasingly will roll in renewable natural gas," Minter said.
Follow me on Twitter @rvartabedian