How a California dairy generates enough power to meet its complete energy needs.
Larry Castelanelli (left) and family members stand atop the cover of the dairy’s methane digester near Lodi, Calif.
Larry Castelanelli continues to be a leader in sustainable energy production, operating one of the longest-running dairy biogas digesters in California.
"In 2003, we decided to make our black-and-white Holsteins green," said Castelanelli who manages his family’s 1,600-cow dairy in Lodi. "Cows have been producing milk on this farm since the 1920s. Now they’re closing in on a decade of producing clean, renewable energy."
Castelanelli’s green energy production begins with a recycling process common on California dairies. Clean water is first used to cool milk tanks and wash cows. Then it’s recycled to clean manure from barn floors. This wash water is then stored in a retention pond until it can be reused as a natural fertilizer for crops such as corn and alfalfa.
Castelanelli made the investment to cover his pond with a thick plastic sheet, strong enough to walk upon. This captures biogas produced from the natural breakdown or "digestion" of the manure during storage. The biogas, mostly methane, is then used to power an engine capable of producing 300 kilowatts of power.
"We generate enough power to meet the complete energy needs of the dairy," Castelanelli says. "When we’re producing more power than we can use, we sell the excess to the utility company. At times, as much as two-thirds of our cow power leaves the farm."
Castelanelli sees his investment as a "win-win" situation. Not only is he reducing greenhouse gas emissions from the farm, he’s also offsetting his use of fossil fuel-generated energy, further reducing the release of heat-trapping gases.
With one of about a dozen dairy digester projects in the state, Castelanelli is hopeful more dairy farmers will be able to implement improved digester technologies on their farms, thereby adding clean, green, renewable energy to the list of products dairy farmers produce for our state and the nation.
"The potential for green energy generation by dairy farmers in this state is tremendous," he says. "You could say I’m bullish about the future of cow power."
Learn more about the sustainability efforts of California’s dairy industry at www.DairyCares.com.