Dairy digester to turn cow waste into valuable electricity

The small city of Galt on Sacramento County’s southern edge was founded by farmers, ranchers and dairymen like Arlin Van Groningen, a third-generation dairy farmer who continues the family tradition on a 90-acre plot off of Harvey Road just north of town.

“We concentrate on cows,” he said. “Our goal is to produce a clean milk product.”

And his 1,200 head of dairy cattle do every day at New Hope Dairy, the operation he owns with fellow dairyman Arlan Van Leeuwen.

But it’s what else New Hope’s herd produces that caught the attention of the Sacramento Municipal Utility District and will soon mean enough electric power for 250 Sacramento-area single-family homes.

Biomass. Wet resources. Manure. Each of Van Groningen’s milking cows produce 120 pounds of combined manure and urine each day. That’s plenty wet resources and more than enough to stock an advanced new dairy digester that produces and collects biogases to generate renewable electricity for SMUD.

The dairy digester – a large storage tank 26 feet deep – collects and breaks down the massive amounts of manure New Hope’s cows produce, then sends the cleaned methane gases to an adjacent generator. The end product: 450 kilowatts of electricity.

Officials at the utility, state and federal energy and agriculture officials, and bioenergy advocates gathered Tuesday at New Hope Dairy to dedicate and tour the project.

“You couldn’t have a better fuel supplier,” said N. Ross Buckenham, chairman and chief executive officer of California Bioenergy, a partner in the three-year, $3.5 million project. “Dairy gas is a phenomenally valuable renewable resource and it’s time has come.”

SMUD is banking on it. The Sacramento utility received $5.5 million in grants from the federal Department of Energy and the California Energy Commission to help bankroll the building of New Hope’s digester and another at the nearby Van Warmerdam dairy in Galt.

German firm MT-Energie built the New Hope facility mimicking technology long used in Europe. The dairy’s biogas facility began operations in June and soon will be connected to SMUD’s grid.

Two other digesters operate in SMUD’s service territory west of Galt and south of Elk Grove. SMUD board president Bill Slaton said the biogas has become a vital part of the utility’s energy portfolio. About 27 percent of SMUD’s energy supply comes from renewable sources, he said.

It’s also a hedge against costly peak-hour power, Slaton said. The New Hope generator produces energy that SMUD would use during the peak hours of 4 to 7 p.m.

“It’s 400 megawatts that we need for about 40 hours a year,” Slaton said. “When you buy it at the peak of the season – that’s a higher cost.”

But financing, regulatory hurdles and other factors have frustrated other California farmers hoping to diversify their dairies by developing biofuels, said Julia Levin, executive director of the Bioenergy Association of California.

“This should be the first of 100 projects. We’re the No. 1 dairy state in the country. We should be the No. 1 dairy digesting state,” Levin said. “It’s unique, but let’s make it one of many, not the only one.”

Van Groningen admits that persuading him to convert his dairy waste into biofuel took some doing.

He wasn’t skeptical of the technology. But, “being in the dairy industry, we’ve seen projects like this come and go,” Van Groningen said. “The technology’s been there for many years, but financing was the biggest hurdle. SMUD tore down walls and made it happen.”

And as the renewables industry continues to grow, New Hope Dairy and other dairy operations are poised to turn waste into a much more valuable resource.

“When he first told me, I said it was a great opportunity to use the byproduct to generate power,” said Arlin’s father Art Van Groningen, a dairy farmer near Visalia in Tulare County. “It’s a whole new way of doing it.”