California is a leader in the development of dairy digesters: reducing emissions and creating clean energy.
California is the first dairy region in the world to set a goal for a 40% reduction of methane emissions from dairy manure. Due mainly to the development of digesters, the state's dairy farms are currently on track to meet that goal.
California is home to 15 “clusters” of dairy digesters in various stages of development. Clusters are groups of digesters that share a centralized gas clean-up facility, where the captured dairy biogas is upgraded and then injected into natural gas pipeline. See the map. Additionally, another 33 California dairy farms have or share access to digesters (operating or in development) that are not a part of a cluster.
In total, California has 227 dairy digester projects, capturing methane from 255 dairy farms, and creating either renewable electricity, renewable natural gas, or hydrogen fuel. About 120 of the digesters are currently in operation, with the rest in development.
California’s dairy digesters show tremendous potential to not only decrease greenhouse gases, but also reduce other air emissions and improve overall air quality.
One cow can produce enough transportation fuel to drive a car across the country. Five cows can power a house for a year.
A pilot program is testing the use of hydrogen derived from dairy biomethane to fuel trucks and cranes at the Port of Los Angeles.
Dairy digesters are providing the largest greenhouse gas reduction of all investments in California’s climate action portfolio.
California's digester grant program is among the most cost-effective programs, providing one ton of GHG reduction (CO2e) for every $9 invested by the state.
(Updated August 2023)
Learn more about the Dairy Digester Research and Development Program in the latest annual report to the Legislature on California Climate Investments Using Cap-and-Trade Auction Proceeds. Learn about the state's comprehensive dairy methane reduction efforts, including alternative manure management practices.
Frequently Asked Questions
How does a dairy methane digester work?
“By covering our pond, we capture the biogas that’s produced from the natural breakdown of manure during storage. You can actually see the plastic tarp on the pond rise as it fills up with biogas.”
– Leo Van Warmerdam, Galt, CA
What does "carbon negative" mean?
According to the California Air Resources Control Board, renewable natural gas (RNG) from dairy biogas is by far the least carbon-intensive transportation fuel currently available in California with a negative carbon intensity score of -255, making it nearly ten times more effective at reducing carbon in the atmosphere than even electric vehicles. To learn more, see Dr. Mitloehner's explanation in the video, How Can We Reduce Livestock Methane?.
How can CA ensure long-term success?
The dairy community is working with government agency partners, technology providers, the energy industry, entrepreneurs, and others to develop cost-effective, environmentally friendly dairy digesters. Dairy families will need continued cooperation from the state to provide infrastructure and robust markets for renewable gas and electricity.
California dairy farmers are leaders in planet-smart dairy practices.
Dairy farmers in California have a long history of working collaboratively with state officials and researchers to improve environmental performance, which has placed them in a strong position to lead the world in the development of climate-smart and planet-smart dairy farm practices. California dairy farmers, state officials, and other key stakeholders meet to advance their shared goals at the California Dairy Sustainability Summit.