June 26, 2006 2:10pm
• Castelanelli Bros. Farm makes its own power from cow waste
• Cows make milk and electricity
Simply put, Mr. Castelanelli is using an on-farm manure digester to make methane gas which is used to power a generator that makes the electricity the farm uses.
The project was highlighted Monday when a delegation from the United Nations toured the farm as part of a two-day trip to the Central Valley to learn more about sustainable agriculture. Delegates came from Bangladesh, Portugal, the Republic of Congo and the Republic of Korea.
“I looked at the whole thing as ‘what’s the worst scenario,’” Mr. Castelanelli says in explaining why he went to the trouble and expense – about $800,000 – to put in the system. “It’d be nice to be self-sufficient and produce our own energy and get off the grid but the worst scenario was that if it didn’t work, we’ve still got a few things we can use here.”
The bottom line economics of the system are still up in the air, he says.
“I have no idea what it’s going to make. The rules and laws are still being changed,” he says. While feeding excess power back into the grid is a simple task for his system, the local utility, Pacific Gas & Electric Co., does not pay enough to make it worthwhile, he says.
The farm already has enough cows and the resulting waste to double its production of electricity, if there were adequate income, Mr. Castelanelli says.
A spokesman for PG&E on Tuesday said when a farm customer generates his own power, it can offset their regular electric bill, but the company is not permited by the California Public Utilities Commission from buying farm-generated excess power.
The concept of the system is a simple one, says Pete Dalla-Betta, an environmental scientist for RCM Digesters of Oakland, who designed the system.
The milking parlor and cow sheds are flushed with fresh well water three times a day. The effluent makes it into the power system.
“In the digester the manure can spend between 40 and 60 days, depending on the flush volume,” Mr. Dalla-Betta says. The digester – a pond with earthen walls 12 feet high -- covers two acres of land. The liquid is completely covered with a thick rubber sheet, strong enough to walk on.
“In that time period, about one-third of the organic matter is converted to biogas,” he says.
The system could be installed on dairy farms throughout the Central Valley if there were enough economic incentives and more encouragement from the government, says Vince Furtado, a field representative for Western United Dairymen in Modesto.
“With the demands we have for power in this state, I think we’ve got a valuable resource here than can help out in meeting our energy demands,” Mr. Furtado says. “If we can work with the utility companies to want to take some of the power that we can generate, it would be good for everybody,” he says.
The powerhouse where the generator runs around the clock sits below the berm. While loud, the generator is located nearly a mile from the nearest residence.
There are other advantages to the “flush system” used at the Castelanelli farm, says Kristen Hughes of Sustainable Conservation of Modesto and San Francisco.
“Flush systems may be ideal for reducing some of the volatile organic compounds and gases that are coming off of dairies. These gases can produce ozone,” Ms. Hughes says.
“So this system is not only reducing emissions from the lagoons, reducing greenhouse gas emissions, but it’s also set up so Larry can flush regularly and cut down emissions from the free stall area as well,” she says.
The Castelanelli power system was selected to be on the tour as a good example of technological improvements being tried by California farmers, says Robert Hodgen, vice president of J.D. Heiskell Holdings LLC of Tulare and one of the organizers of the tour.
“The methane digester here at the Castelanelli dairy we feel is an important part of sustainability and one of the more technologically advanced parts of agriculture here in California,” Mr. Hodgen says.
But getting to the point where his family farm is featured on a Central Valley tour of bigwigs has not been without its problems, Mr. Castelanelli says. In addition to the costs and the usual problems inherent in building anything new has come the disappointment in trying to sell his power to PG&E, he says.
Would he do it again?
“If I was getting paid what I should be getting paid for electricity, it’d be worth it,” Mr. Castelanelli says. “Because of the law and the way it is written, I’d question doing it again.”