Van Warmerdam Dairy Digester a Big Deal for Renewables

Maas Energy Works—a company specializing in turning methane gas generated by cow manure into electricity—finished construction last year on a digester at the Van Warmerdam Dairy. This Sacramento County facility that milks 1,000 cows became operational in July 2013, with offsets scheduled for delivery in March 2015.

The digester covers the existing lagoon at the dairy with a flexible, high-density polyethylene cover, which stores up to two days of biogas production. Essentially, the digester is used like a battery, combusting the gas to generate electricity only during peak times.

“The Van Warmerdam project is a big deal for renewables,” said Peter Weisberg, Program Manager for The Climate Trust. “We don’t have power over when the sun shines or the wind blows—so balancing the grid is essential and biogas lets us do it with more renewables.”

The combined heat and power engine of the digester has a capacity of 600 kw, and the project has a twenty-year Power Purchase Agreement to sell this power and its Renewable Energy Certificates to the Sacramento Municipal Utility District. Based on a modeling of the methane emissions from the pre-digester lagoon at the Van Warmerdam Dairy, the project is anticipated to deliver 68,500 credits over a ten year crediting period.

California has a very large and mostly unrecognized opportunity to develop biogas projects. This is The Climate Trust’s first California project and therefore an important first step towards future work in the state with Maas Energy Works and others.