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Published December 25, 2009, 09:14 PM

Ethanol plant burns corn cobs

A southwest Minnesota ethanol company will buy more than just corn from farmers. It wants their cobs, too.

By: Heather Thorstensen, Associated Press

BENSON, Minn. — A southwest Minnesota ethanol company will buy more than just corn from farmers. It wants their cobs, too.

Chippewa Valley Ethanol Company in Benson is using about 70 tons of corn cobs, wood and glycerin per day in their gasifier. They burn the gas for steam, which is used as a heat source to make ethanol.

CVEC hopes to eventually reach 300 tons of biomass per day, which would replace 90 percent of the natural gas they use with renewable sources. Currently, they’re replacing 20 percent.

Andrew Zurn, CVEC’s engineering manager, said Dec. 2 at a University of Minnesota-sponsored renewable energy conference that the ethanol plant’s leaders chose to use cobs because they are easy to find. They also wanted to provide another source of income for their farmer members. CVEC is a cooperative with 980 farmer and local owners. It makes 48 million gallons of ethanol each year, alongside other products, like vodka.

“We want to spend our energy dollars locally,” Zurn said.

They also like cobs because it’s a way for the company to take more control of their energy costs while creating a smaller carbon footprint.

So far, they’ve found cobs are economically viable.

The plant is projecting a 2009 cob harvest of 6,000 to 8,000 tons from 12,000 to 14,000 acres. They would like to build up to receiving 20,000 to 30,000 tons of cobs per year.

So far, it’s profitable for farmers. The co-op can pay $90 to $100 per ton while CVEC estimates it costs a farmer $66 per ton, or $33 per acre, to harvest and deliver them.

CVEC’s cob price is supported by a USDA Farm Service Agency initiative to help biomass markets get established. The Biomass Crop Assistance Program matches the payment CVEC gives cob producers, up to $45 per dry ton. CVEC announced in October they were one of Minnesota’s first facilities to qualify for the program. BCAP’s matching payments last two years.

Local growers collect cobs with special equipment. One type of cob harvester uses a wagon pulled behind the combine. Another type keeps grain separated from cobs in a hopper on top of the combine. Either way, their designs don’t require a farmer to make extra passes down the field. Cobs are collected before they even hit the ground, so CVEC doesn’t have to worry about dirt and debris.