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Spokane farmer generates power from harvest residue

Published on June 26, 2010 3:01AM

Last changed on July 24, 2010 7:09AM

Capital Press file
David Gady, left, and Jack Zimmer discuss the gasifier project taking shape on the Gady family's wheat and bluegrass seed farm south of Spokane.<br>

Capital Press file David Gady, left, and Jack Zimmer discuss the gasifier project taking shape on the Gady family's wheat and bluegrass seed farm south of Spokane.

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Small energy producing system could eventually power 150 homes

For the Capital Press

There's a lot of interest in what's been unfolding at a Kentucky bluegrass grass seed farm near Spokane, Wash., the last several years, but it has nothing to do with seed production.

Instead, the focus is on an experimental generator designed to produce on-farm energy from residue left over after seed harvest.

"Is (energy generation) feasible on the farm? I think yes," said Gary Banowetz, who heads up research at USDA-ARS's National Forage Seed Production Research Center on the Oregon State University campus.

Banowetz has been working closely with the generator designer to develop a reliable system to produce energy from crop residues and tailings from seed cleaning operations.

He said that unlike the Midwest, where field corn is grown in abundance for ethanol production, the biggest resource for biomass in the Northwest is the residue from grass seed, cereal and forestry operations.

"And that straw isn't worth very much (as cattle feed), or energy dense (like corn)." What's more, he added, hauling the straw to a large export or energy generating facility "just isn't economical."

Thus, the interest in the local use of the residue to produce energy on the farm.

"What's unique about our approach, for a lot of the straw in the Northwest we feel a much smaller scale ... will work economically," Banowetz said.

By smaller scale, he's talking grass seed and cereal farms as small as 1,100 acres.

"We think there will also be opportunities for multiple small farms to come together (to produce energy)," he said.

The Spokane generator, which was designed by David Gady and is located on his father Larry's farm, has been working mostly with grass straw and tailings from the farm's seed cleaning operations.

Gady, who has a master's degree in engineering from Washington State University, designed the modular system to produce carbon monoxide and methane in a low-oxygen environment.

The two gases are ignited in the combustion chamber to power the pistons that drive the generator.

While the system has not yet produced any electricity, Gady said the 375 KW unit will power 150 homes. Dairy farms, processing plants, mills and seed cleaning operations are also potential customers for the generated electricity.

The amount of biomass it takes to produce a specific amount of energy varies, depending on the species of grass seed grown and whether the crop was irrigated, Gady said. He added that it takes around three pounds of grass biomass to produce 1 kilowatt of power.

In addition to electrical energy, the generator also produces a large amount of heat, which has uses, Gady said. The ash remaining after combustion is another byproduct that could be used, among other things, as a soil amendment.

Banowetz said that smaller energy producing systems could be made available to farmers for about the price of a new combine -- $300,000 to $350,000.

Funds to help build the Spokane generator came from state government at the urging of a local group of farmers and interested citizens called Farm Power. Bonneville Power, Inland Power and Square D Electric contributed equipment.

Banowetz hopes to find the funds to build a generator in Oregon's Willamette Valley, the grass seed capital of the world.

He said that because of the heavy rainfall in the valley, grass seed straw is double that produced on dryland farms in eastern Washington.


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