While underground resources such as coal, oil, and natural gas supply most of America’s energy, many people are looking at potential energy resources on top of the ground—and farms offer some innovative solutions.
“Bioenergy” is the recently coined word for energy produced from plant or animal products. Bioenergy uses renewable resources, putting it in the “green power” category of energy sources.
Most people are familiar with one of the most successful bioenergy products, the ethanol added to traditional motor fuels. So far, the ethanol in service station pumps in Kentucky comes from crops produced by out-of-state farmers at out-of-state processing plants.
That’s about to change as the result of an effort by Hopkinsville Elevator Company Inc., a 2,300-member grain cooperative headquartered in Christian County. Working with the Kentucky Corn Growers Association and a $9.5 million grant from the Kentucky Agricultural Development board, it’s building a 20-million gallon ethanol processing plant scheduled to begin producing ethanol in the spring of 2004. It will provide a market for Kentucky grains, a popular choice for farmers who no longer grow tobacco.
Ethanol works great as a fuel component for vehicle engines and helps add diversity to the supply of energy for cars and trucks. But what about using farm products for another part of the energy industry, generating electricity?
One answer involves a livestock byproduct: manure.
Nationally, as farms increase in size, the concentration of manure increases, too. Finding practical ways to deal with the odor, then disposing of the manure while still meeting environmental regulations, is a real challenge.
Trying to turn that challenge into an asset, a few years ago Energy Co-opportunity (ECO), an energy diversity co-op created by 300 electric cooperatives in the United States, played a vital role in one of the first practical tests of a new way to produce green power.
On paper, the idea was simple—collect manure, capture the naturally occurring methane gas, then burn the gas to power a small turbine to produce electricity. Reality gets more complicated, as demonstrated by a test at a 900-cow dairy farm in upstate New York. At this test site, manure first goes into an anaerobic digester, a huge covered, self-contained system that prevents the manure from contaminating nearby water supplies and confines most of the odor. In the digester, the organic material in the manure decomposes, producing methane gas. The methane then goes through a conditioner to prepare it for use in the power plant. An assembly of several microturbines generates electricity, and a heat recovery system helps improve efficiency.
However, very few dairy farms in Kentucky are as large as the New York demonstration farm. Would such a system work in the Bluegrass State?
Scott Drake, a senior engineer with East Kentucky Power, an electricity generating and transmission co-op based in Winchester, describes a recent bioenergy feasibility study.
“We put together a team of people from Eastern Kentucky University in Richmond, Meadowbrook Farm (EKU’s agricultural farm in Madison County), Bluegrass Energy (a local electric distribution co-op), and RCM Digesters, a manufacturing company in Berkeley, California,” Drake explains.
The careful study of the farm’s situation concluded that there would be enough manure to produce enough methane to power a small engine such as a Ford 300 bio-gas engine or a slightly larger capacity modified Caterpillar diesel engine to generate about 29 kilowatt-hours of electricity.
That’s enough electricity for daily use on the farm, with an added bonus. The surplus heat from the system could be used to heat water to run under the floor of the piglet areas, eliminating the need for the more usual electric heat lamps required to maintain young piglets’ body temperature at the proper level. This would lower the farm’s overall electricity use—and the electricity generated right on the farm would meet the farm’s remaining needs. The farm would save the amount of money it usually spends on electricity from a utility.
But eliminating that monthly expense doesn’t give the whole picture. It would cost a lot of money to set up a manure-to-electricity system and maintain it in working order. So the final question became, would the electricity generated from manure be more expensive, about the same, or less expensive than electricity purchased from a utility?
The answer: much more expensive due to the investment in capital equipment that wouldn’t pay for itself for 20 or 30 years.
“We think the break-even point may be in the range of 300 to 500 head of dairy cattle, and very few Kentucky farms are that large today,” Drake says. “Also, electricity is so cheap in Kentucky that farmers in our state don’t have much incentive to invest in this new technology at this time.”
The possibility still intrigues many people, especially if a farm could produce enough electricity to have a surplus to sell to others seeking green power. But the day when animal manure becomes a common source of electricity still seems pretty far in the future. For Kentuckians, bioenergy from farms is more likely to end up in their gas tanks, not their power lines.
To find out more about bioenergy visit this Web site: www.eere.energy.gov/biopower/main.html.
Next Month: Electricity from garbage