June 12, 2003

 

Ethanol from Switchgrass?

Can switchgrass, a perennial grass native to our area, be economically grown for use as ethanol? That’s the question researchers at the North Dakota State University Central Grasslands Research Extension Center in Streeter, USDA-Agriculture Research Service and the University of Nebraska are examining.

"The research will determine the economic costs associated with turning switchgrass into ethanol," according to Paul Nyren, director at the Center. "To do that we need to determine yields on a field scale and stand stability over a period of years."

Field tests began in 2000 and will continue through 2005. Testing is taking place at 11 sites in Nebraska, South and North Dakota. Nineteen acres at the Streeter Grasslands Center have been planted to switchgrass.

The Department of Energy has designated switchgrass as a potential biomass energy crop. As a biomass energy crop, switchgrass would be grown on CRP-type land and harvested, baled and hauled to an energy conversion plant. "Assuming a conversion rate of 75 percent at the processing plant, a ton of switchgrass would produce approximately 80 gallons of ethanol," Nyren says.

So far, costs during the first year when switchgrass is planted are the highest with declining costs as yields increase in subsequent years. "Cultural practices such as seeding depth, density, weed control and cultivation practices need additional research," Nyren says.

First-year costs per acre ranged from $40 to $160, averaging $75. The cost per ton ranged from $50 to $150, which included harvest expenses but not land costs. Costs per ton could go as low as $30 per ton once good management techniques are established. Costs for hauling switchgrass to a processing plant are likely to add another $10 per ton. The data from Streeter and other sites indicates that a stand of 1 to 2 plants per square foot is sufficient to grow switchgrass for ethanol conversion.

Much of the success of switchgrass as a potential fuel source rests with Department of Energy and USDA-Agriculture Research Service researchers working on new technologies for a switchgrass-to-energy conversion system. "It will probably be a few more years before we know the results of those experiments," Nyren says. Researchers are also studying a system of burning switchgrass with coal to generate electricity.

Another possible benefit of raising switchgrass is its potential to store carbon dioxide in the soil. Plants take in carbon dioxide as they grow. The carbon dioxide is returned to the soil and stored there after the plants die and decompose thus removing some of the excess carbon dioxide in the air.

Part of the current research at the Grasslands Center involves measuring the amount of carbon stored in the soil to determine if switchgrass, grown as a biofuel crop, stores the equivalent amount of carbon dioxide as it does on CRP grasslands.

Researchers involved in the project will be on hand during the Center’s annual field tour, Wednesday, June 25. The tour begins at 6 p.m. It is located four miles north of Streeter, or 11 miles south of I-94 on Highway 30. Take Stutsman County Road 38 and drive five miles west and one-quarter mile south.

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Source: Paul Nyren: (701) 424-3606, paul.nyren@ndsu.nodak.edu
Editor: Rich Mattern: (701) 231-6136, richard.mattern@ndsu.nodak.edu