Turning manure into energy

California dairy farmers discover they can convert manure into electricity with 'dairy digester' machines. But some local air regulators are not pleased with the technology.

By E.B. SolomontMon, Mar 01 2010 at 1:41 PM EST

(Photo: Charlie Litchfield/AP Photo)

Manure may be of one the stinkiest pollution problems, but it has a green lining: it's renewable energy.

A handful of California dairy farmers have begun using methane gas from cows’ waste to generate electricity, the Los Angeles Times reports. But just as the idea was starting to catch on, state regulators began refusing to issue permits for “dairy digester” systems because they claimed the technology creates its own pollution, nitrogen oxides or NOx.

"The board has been clear that when we're faced with these sorts of trade-offs between reducing greenhouse gases and reducing NOx, we're going to choose NOx,” said Dave Warner, director of permit services for the San Joaquin Valley air quality district. His office has blocked some farms from switching on their digester machines.

Certainly, the potential is there. Central California is home to nearly 1.6 million dairy cows that produce up to 192 million pounds of manure a day. “California has about four times as much potential for emission reductions and energy generation as the next-largest dairy state,” an EPA official told the paper. “I know the regulations are much more strict in California. But there's so much potential there.”

In fact, the idea has caught on in Europe, where more than 8,000 biogas operations are up and running. In the United States, though, the concept has been slower to catch on, in part because government subsidies are not as readily available. Only about 150 digesters are operating on American farms, including 19 in Wisconsin, 18 in Pennsylvania and 16 in California.

The current standoff between farmers and regulators isn’t making things easier.

The L.A. Times reports that farmer John Fiscalini installed a $4 million digester system when regulators warned him that he needed to lessen pollution emitted by his 530-acre farm and cheese factory in Modesto, Calif. Now, several times a day a generator flushes tons of manure out of his barns and converts the methane into electricity.

But to comply with air standards, he had to invest hundreds of thousands more into his equipment.

“I figured I might as well try to do this now and do some good,” Fiscalini recalled. Now, he says: “I wonder, sometimes, why I ever thought this was a good idea.”

But another farmer says the air regulators aren’t completely off-base. Dairy farmer Ron Koetsier installed a digester in 2003, but shut it down five years later when he was told it violated local NOx emission standards. The cost of upgrading his system would have been too high: $100,000 in new parts plus $50,000 a year in maintenance fees.

“It doesn't make financial sense for me keep doing this. I don't see how they can turn methane gas into electricity in California, given these rules,” he said. But he added: “They have a point. I want clean air.”