The Iowa Association of Rural Electric Cooperatives held its annual meeting in Des Moines last week. One of the main topics of discussion among the 500 people attending was renewable ways of generating electricity. Kendrick Scaville, a spokesman for Dairyland Power, a rural electric co-op in LaCrosse, Wis., was one of the speakers. That co-op is using renewable sources of fuel to make some of its electricity.
"Dairyland Power has been very aggressive in building its use of renewable resources to manufacture electricity," he says. "Our board of directors has been very supportive and our membership has encouraged us to do this. So we are doing a number of things to foster the availability and use of renewable energy."
Renewable energy from several sources
About one-fourth of the co-op's renewable energy is coming from hydroelectric power that's been around for 50 years. Another one-fourth is coming from wind-generated energy. "We purchase power from individuals who have built wind-turbines on their land. They sell the electricity to Dairyland Power," he says.
Another one-fourth of the co-op's renewable energy comes from landfill gas—methane that is collected and used to make electricity. The methane gas generated by landfills is actually captured, and is burned in an engine and then turned into electricity.
The final one-fourth of the co-op's renewable energy is coming from methane digesters on livestock farms. "We literally cook the manure that comes from the livestock farms," he explains. "Methane is produced and is used to power engines that turn the generators to make electricity."
Methane digesters used on livestock farms
The nice thing about both the methane digesters and the landfill gas projects is they run around the clock, 24 hours per day, 7 days per week. "We know when we're going to be getting electricity from that," he notes.
How much energy, on a number of houses or customers served basis, can you get from dairy cattle manure? "Our typical methane digester produces methane from 1,000 cows," says Scaville. "We produce enough electricity to power 500 homes from those 1,000 cows."
Looking at the numbers, you can see that it really doesn't take very many cows to produce the power to run a single home, and this has proven to be a very positive energy balance. More dairy farmers would like to have manure digesters on their farms to generate methane and electricity, but it takes additional workers and expense. The question is how do you make it pay? What's the prospect in an area of these dairies to bring the manure to one central location and make the methane in a larger, more efficient operation? The flipside of that question is that it doesn't pay to haul manure too far.