A first-of-its-kind anaerobic digester in California captures methane from agricultural waste and turns it into clean biogas to power an ethanol facility in Tulare County.
The Calgren Ethanol Biodigester, which is now online, will power the production of tens of millions of gallons of ethanol, all consumed in California’s Central Valley, and it expected to reduce the environmental impact from farm waste greenhouse gas emissions by more than 90 percent, says Steve Dvorak, owner and founder of DVO.
DVO designed the Two-Stage Mixed Plug Flow Digester, which was built by Regenis.
The process begins with dairy Four J Farms sending cow waste to the Calgren digester, which captures methane and burns it as clean biogas. While Calgren will be utilizing the renewable gas to power its facility, the digester will also greatly reduce bacteria and pathogens so dairy farmers can reuse the liquids safely on their crops, saving millions of gallons of water and protecting watersheds.
Digesters have other advantages as well, including reducing air and odor emissions. According to the American Biogas Council, replacing just 10 percent of California’s natural gas supply with renewable gas would reduce greenhouse gas emissions by tens of millions of metric tons per year, while cutting wildfire, air pollution and landfilling — issues raised by the California Energy Commission when it invested $4.6 million in the project.
“The San Joaquin Valley is challenged with some of country’s worst air pollution,” said Janea A. Scott, CEC commissioner. “The Pixley Biogas anaerobic digester is the first anaerobic digester on a California farm permitted to use all feedstocks, including municipal green waste and food processing waste.”
The green technology will help the state meet its clean air, petroleum reduction and climate goals, Scott said.
