SMUD enlists cows at two Galt dairies to produce more than just milk

The typical dairy cow produces six to seven gallons of milk each day. She also generates 120 pounds of manure and urine every day.

Now, with dairy digesters recently installed at two dairies in Galt, neither product goes to waste. In fact, cow waste produces electricity that keeps the milk in your refrigerator cold.

With assistance from the Sacramento Municipal Utility District (SMUD), the New Hope and Van Warmerdam dairies recently installed anaerobic digesters that convert cow manure into clean, renewable electricity. SMUD received approximately $5.5 million in funding from the U.S. Department of Energy and the California Energy Commission to help fund the construction of the digesters at the New Hope and Van Warmerdam dairies. Federal funding came from the Department of Energy’s Community Renewable Energy Deployment (CRED) grant program under the American Recovery and Reinvestment Act.

“I applaud the creative partnership between SMUD and the dairies to turn waste products into energy,” said Congresswoman Doris Matsui. “This type of collaboration enables us to continue to meet our renewable energy goals and transition to cleaner, more efficient energy sources. It is also a prime example of how targeted federal investments can spur innovative ideas and new technologies.”

At the New Hope dairy, the collected manure is pumped into a concrete and steel tank, where biogas (primarily methane) accumulates and is then transferred to an engine-generator that produces clean electricity. New Hope also uses a scrape system rather than a flush system to collect the manure, greatly reducing the use of fresh water at the dairy. At the Van Warmerdam dairy, the waste decomposes in a covered lagoon rather than in an above-ground tank.

Together, the two dairy digesters are capable of producing 4.3 gigawatt-hours of electricity – enough to power roughly 450 single-family homes.

There are now four dairy digesters operating in SMUD’s service territory, representing about 31 percent of California’s total. The benefits are numerous. Dairy digesters keep climate-changing greenhouse gases out of the atmosphere while creating a revenue source for the farmers and supplying renewable energy to SMUD. The digesters also reduce odors and flies compared to conventional open lagoon storage. The effluent is used as liquid fertilizer for crops.

“We believe that cows are a good thing, but we have to be mindful of our neighbors and the area we live,” said Arlin Van Groningen, co-owner of the New Hope dairy. “Having a digester that destroys carbon that would have ended up in the air is a good thing.”

MT Energie and ABEC New Hope LLC built the tank digester at New Hope. The Van Warmerdam digester was built by Maas Energy. In both cases, third-party developers have leases with the farmers for the site and the manure supply. The farmers receive financial and environmental benefits from the projects. The clean power is sold to SMUD and delivered straight into the electric grid.

SMUD was the first large California utility to have 20 percent of its power supply come from resources classified as renewable by the state of California. SMUD is on track to reach the 33-percent mark by 2020.

When most people think of renewable power, they generally think of wind and solar. But biomass accounts for roughly 50 percent of SMUD’s renewable portfolio. SMUD is leading the way to have more small-scale biomass projects built.

“With many biomass projects, you not only have to build the project, but you also have to go after the waste, or the fuel,” said Marco Lemes, SMUD’s project manager. “With dairies, the fuel is already here. It’s being used on-site.”

About SMUD

As the nation's sixth-largest community-owned electric service provider, SMUD has been providing low-cost, reliable electricity for more than 65 years to Sacramento County (and a small portion of Placer County). SMUD is a recognized industry leader and award winner for its innovative energy efficiency programs, renewable power technologies, and for its sustainable solutions for a healthier environment.

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