CalBio adds 8 Mainspring generators at biogas sites

California Bioenergy LLC (CalBio) has purchased eight additional Mainspring Linear Generators to be deployed at its North Visalia and South Tulare cluster of biogas upgrading sites in California.

CalBio, a Tulare, California-based producer of renewable natural gas from dairy waste, says the investment will build on its early success with linear generators, having expanded these dairy biogas fueled systems statewide. The firm says these projects improve local air quality for its surrounding communities while also generating a new revenue stream for the dairy farmers.

According to the firm, its operations account for an annual reduction of about 1.9 million metric tons of carbon dioxide equivalent. CalBio says it intends to build on this impact by broadening its collaboration with Mainspring Energy, which is based in Menlo Park, California.

“To lead the state in dairy methane emission reductions, while also supporting our local family dairies and communities, requires a constant focus on innovation as well as efficiency, resilience and cost reduction,” CalBio Chairman and CEO N. Ross Buckenham says. “We’ve seen what linear generators can achieve, and we are proud to be leading in delivering the valuable benefits of Mainspring’s power design to the dairy industry.”

CalBio began deploying Mainspring Linear Generators throughout California sites in 2022 with an initial 1-megawatt (MW) installation at its Hanford cluster upgrader. It has since added 1 MW at its Buttonwillow cluster upgrader and 1.5 MW at a standalone dairy digester project in Merced County.

With the addition of 1 MW systems at both its North Visalia and South Tulare cluster upgraders, CalBio and Mainspring expect to operate a combined 5.3 MW across all five sites by the end of 2026. This expanded deployment strengthens the long-standing partnership between the two companies and reflects their shared commitment to scaling waste-to-power operations, strengthening rural energy resilience and delivering environmental benefits to local communities.

CalBio says it selected Mainspring Linear Generators for their distinct combination of features, including fuel flexibility, fast-ramping dispatchability, cost-effective design and optimized efficiency over traditional generators. Mainspring manufactures and delivers fuel-flexible, low-emissions local power solutions designed to deliver reliable, affordable and sustainable electric power.

“It is a privilege to work with a leading agricultural sustainability leader like CalBio,” says Adam Simpson, Chief Commercial Officer of Mainspring. “They have led the way on extending Mainspring’s success in running biogas operations at landfills and wastewater plants into the dairy sector, the leading agricultural commodity in California. CalBio’s operations significantly reduce California’s dairy methane emissions and help make California dairies among the most sustainable in the world.”