CalBio Expands Mainspring Linear Generator Operations to 5.3 MW Across Five California Sites

TULARE, Calif. and MENLO PARK, Calif., Feb. 23, 2026 /PRNewswire/ -- California Bioenergy LLC (CalBio) and Mainspring Energy (Mainspring) today announced CalBio's purchase of an additional eight Mainspring Linear Generators to be deployed this year at its North Visalia and South Tulare cluster biogas upgrading sites.

CalBio was the first dairy digester developer in the U.S. to deploy linear generators fueled by dairy biogas. Building on that early success, CalBio has continued to expand these systems across multiple dairy clusters statewide. These projects improve local air quality for its surrounding communities while also generating a new revenue stream for the dairy farmers.

"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," said N. Ross Buckenham, CalBio Chairman and CEO. "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 in 2022 with an initial 1-megawatt (MW) installation at its Hanford cluster upgrader and 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 the 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.

"It is a privilege to work with a leading agricultural sustainability leader like CalBio," said 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."

CalBio's operations account for an annual reduction of approximately 1.9 million metric tons of CO₂e, equivalent to removing more than 430,000 gasoline passenger vehicles from the road. Building on this impact, CalBio and Mainspring will continue their collaboration to deliver reliable local energy and long-term environmental and economic benefits for family dairy farms and surrounding rural communities.

CalBio 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. The products' extremely low NOx output (<1.5 ppm) meets the most stringent local, state and federal air quality standards, without requiring use of special after-treatment.

About CalBio
California Bioenergy is the leading developer, builder, operator, and largest U.S. producer and marketer of renewable natural gas from dairy waste. CalBio's dairy digester projects generate ultra-clean and negative carbon intensity, renewable natural gas, vehicle fuel, and electricity. Founded in 2006, CalBio partners with dairy families and local, state, and federal agencies to operate projects that empower the industry to achieve methane reduction goals, protect local air and water quality, and create local jobs while also improving the long-term viability and economics of its partner dairies. CalBio is currently operating or developing over 120 dairy digester projects in California and through its Midwest, Northwest, and Southwest affiliates. For more information, email us or visit our website at calbioenergy.com.

About Mainspring
Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Learn more at mainspringenergy.com.

SOURCE Mainspring Energy, Inc.