ST. EUGENE -- It may not seem green, but power produced from what comes out of the back end of a cow is classified as such and is becoming more and more marketable.

The first farm biogas system in Ontario to sell electricity to the grid -- St. Eugene's Terryland Farms -- will show how it's done during an open house this Saturday, 10 a.m.-4 p.m., at 1670 Concession Rd. 6 here.

Alfred Campus of the University of Guelph will make special presentations at 11 a.m. and 2 p.m. on the basics of biogas and the economics of a farm manure digester.

Terryland owner George Heinzle is throwing open his recently commissioned $400,000 system installed by Genesys Biogas Inc. of Ottawa to explain and promote the concept to others with an interest. And there's lots of interest out there, said Heinzle, noting that many farmers are treating his digester as a pilot project.

Simply put, the system permits manure from Heinzle's dairy cows to be "digested" and used to turn on lights and heat homes. In addition to manure, the digester can also be fuelled by crops, crop residues and food processing byproducts.

Biogas is a combination of methane and carbon dioxide from the digestion process. It can be used to fuel an internal combustion engine, powering a generator which produces electricity.

A biogas system that uses manure from 250 cows could result in 400 fewer tones of greenhouse gas emissions and in 550 additional megawatt-hours of power every year. The system also reduces odours by up to 95%, pathogens by 97%, and improves the fertilizer value of processed manure.

Heinzle signed a 20-year contract to sell power at 11cents/kWh, with a 3.5cents premium at peak hours. That price makes a digester barely profitable, the farmer said; a fairer price would be 15cents/kWh, he said.

By processing other suitable waste brought to the farm, Heinzle hopes to eventually produce 4,000 kWh every day; that could bring in more than $13,000 a month in sales to the grid.