This is an excerpt from EERE Network News, a weekly electronic newsletter.

July 17, 2002

New Projects and Laws Advance Manure-to-Energy Systems

If you're a farmer looking for a way to dispose of manure and reduce odor problems, anaerobic digesters are the latest and greatest thing. The technology uses natural processes to decompose manure, releasing methane gas that can be used for power production. Recent projects, technology advances, and laws suggest a growing role for anaerobic digesters on farms.

On July 11th, Environmental Power Corporation announced that it has signed letters of intent with six farms near Green Bay, Wisconsin, for the construction of an anaerobic digester at each farm. The company claims the six farms will generate a total of about 10 megawatts of power, which will help meet the peak power needs of the Wisconsin Public Service Corporation. Environmental Power has already signed a 15-year agreement to provide 15 megawatts of peak power for the electric utility, and hopes to sign up additional farms for anaerobic digester systems in the near future. The six new farm energy systems are expected to be operating by August 2003. See the Environmental Power Corporation press release.

A new anaerobic digestion technology also marked a milestone on July 11th, when the Enviro-Energy Corporation completed the initial startup of its prototype system at a farm in Tillamook, Oregon. The company claims to have developed a continuous process for converting manure to methane and fertilizer - most current systems convert the manure one batch at a time, rather than continuously. Last week, the new system starting producing methane, which was flared off. The methane will eventually power an engine-driven electrical generator. See the Enviro-Energy Web site.

New anaerobic digesters may soon start appearing in Vermont, since the state just expanded its net metering law to allow for anaerobic digesters up to 150 kilowatts in capacity. Net metering allows grid-connected systems to turn the electrical meter backwards when the system feeds power back into the electrical grid; each month, the owner pays for only the net amount of electricity used. The Vermont law allows farmers to combine multiple electricity meters onto one net-metered bill and also allows farmers (and homeowners) to carryover any net electricity generated from month to month during each calendar year. See Section 219a of the Vermont bill.

See also the explanation from the Database of State Incentives for Renewable Energy (DSIRE) Web site.