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The power of cow manure: Is it too noxious?

March 2, 2010 |  3:51 pm

The idea seems like a slam dunk, a win-win-win for the environment, farmers and politicians hunting for green-energy solutions: Turn cow manure into electricity by collecting the methane gas released off the dung, compressing it, running it through a generator and voila! You have a renewable, seemingly never-ending (though very fragrant) source of electricity.

Great, right? After all, methane released into the air is a greenhouse gas 25 times more powerful than carbon dioxide, scientists have found.

There’s only one problem: Turns out that the generators used to turn the gas into power emit nitrogen oxides, or NOx. Some emit more NOx than others. And while methane may damage the planet, it doesn’t damage -- at least, not in the immediate sense -- people’s health like NOx does.

So central California, with its air pollution problems, is seeing some of the country’s strictest standards for what sort of digester generators can -- or cannot -- be used out on the farms. Some say they’re stricter than what dairymen are working with in Wisconsin, Pennsylvania or New York -- and all because California’s NOx problems are … well … noxious.

Getting such systems permitted, though, has become a real headache for many California farmers, so state folks are trying to work together to figure out some of these hurdles. The Central Valley Regional Water Quality Control Board has paired up with a team of other state and local agencies to pull together a programmatic environmental impact report for anaerobic manure digestion and co-digestion facilities. The goal, say board officials, is to streamline the process for farmers and others to get the appropriate permits from state and local agencies.

There’s also a push to capture the energy in a cleaner way. There are plans being bandied about to use biogas to power fuel cells. And three dairies -- Joseph Gallo Farms of Atwater, Hillcrest Dairy Farms in Le Grand and Lima Farms in Lodi -- have signed an agreement with the state Department of Food and Agriculture, the Merced Irrigation District and an environmental engineering firm to roll out pilot projects that will use digesters, algae ponds and other means to turn the waste into energy.

One of their goals? If NOx is created, why not use it to help fuel an algae farm?

To read more about what's happening in California, check out this story. And curious about how the process works? Then watch this slide show.

-- P.J. Huffstutter

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