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Brue receives second energy grant

By Sally Jongsma

In early October, Dr. Ethan Brue and his engineering students harvested a three-quarter acre plot of sweet sorghum they had planted near the engineering building. The sweet sorghum they grew is the biomass that will be converted to fuel in the small-scale biomass-to-ethanol system they plan to design and build in the coming year.

After they harvested the sweet sorghum on October 4, Dr. Ethan Brue and his students squeezed the juice from
the stalks as they prepared to demonstrate a simple process for converting the crop to ethanol.

After they harvested the sweet sorghum on October 4, Dr. Ethan Brue and his students squeezed the juice from the stalks as they prepared to demonstrate a simple process for converting the crop to ethanol.

Brue was awarded the grant from the Iowa Energy Center last spring for a project in which he and his students will design a simple, small-scale field-to-fuel processing system that could be a viable way for local farmers to produce some of their own energy resources.

Brue’s interest in using sweet sorghum began when he was a child. He grew up in a family that was conscious of energy conservation. As a family they designed and built their own energy-efficient home, heated by wood energy. His father, a college mathematics professor who did some farming in the summer, experimented with converting sweet sorghum to fuel. He processed enough to experiment with using the fuel in a car, a tractor, and even a lawn mower. Based on his research since then, Brue believes that farmers could viably produce enough fuel for their own on-farm use and possibly more.

In his interaction with industry through the work of the engineering department, Brue discovered that Vermeer Manufacturing in Pella, Iowa, which has for years served agriculture and industry with innovative agricultural and environmental products, was also interested in pursuing research in biofuel production. As a company that has supported the Dordt College engineering department over the years and has hired Dordt engineering graduates, Vermeer was eager to pursue this collaboration and agreed to co-sponsor the proposal. Vermeer was also willing to help Brue and his students fabricate any system components that couldn’t be made on campus.

Using sweet sorghum, a grass crop that resembles sugar cane, allows the processor to skip a common step needed in the conversion of grain to fuel—turning the grain into a simple sugar. As a result, the fermentation stage of production requires less energy to convert biomass to ethanol. Sweet sorghum can also provide a higher yield per acre than conventional starch crops, while taking less fertilizer to grow, and the cost of sorghum seed is substantially lower than corn seed. The major problem for large-scale production is storing the biomass, which is in the form of a juice that may spoil, instead of a dried grain. But if individual farmers could convert the juice to ethanol soon after harvest, they could easily store, use, or sell the fuel end-product throughout the year.

Brue believes farmers could easily produce enough to run their own equipment and possibly sell off their excess locally or to ethanol distributors. “The potential markets for this farm-produced fuel would need some developing,” he says, noting that many farmers use pickups and equipment that are diesel powered today. But if locally-produced sweet sorghum ethanol were viable, the incentive to purchase ethanol powered vehicles (such as E-85 trucks and cars) may continue to increase. Brue acknowledges that his idea is still part dream, but he notes that the process itself is proven and is really a revisiting of work done in the 80s and 90s.

Brue began work on the project in August. He and his students will design distillation, fermentation, and dehydration systems for sweet sorghum that can be built economically. Following this year’s research and design work, Brue and his students will present their work to local farmers at Dordt’s annual 2008 fall field day. In the meantime he and his students hope to team up with the agriculture department to plant a larger crop of sweet sorghum next summer at the Dordt College Agriculture Stewardship Center to continue their work on a slightly larger scale.