Best Practices in Sustainability: UI Fuels Energy Needs with Oat Hulls

Nov. 7, 2005

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An energy production project involving cereal-mill waste at The University of Iowa (UI) in Iowa City, IA, has earned several awards at both the state and national levels for its success in creating an environmentally responsible method of generating power for the 1,900-acre campus. The Biomass Fuel Project has been cost-effective as well: The university reports it is saving approximately $500,000 per year in facility operating costs.

The idea was conceived in 2002 when the Quaker Oats plant in Cedar Rapids, IA, contacted the UI about implementing a sustainable procedure for disposing of the cereal mill’s oat hulls - the outer shell of an oat grain that remains after the soft protein core is removed. This particular Quaker Oats plant has the capacity to hold 3 days’ worth of oat hull waste, but must remove about 350 tons per day to avoid reduced productivity.

A potential solution was found when university officials agreed to have Quaker Oats regularly transport tons of oat hulls in large trailer trucks to the campus’s power plant, just 30 miles south of the Quaker Oats facility. The disposed hulls would be added to burning coal normally used for energy generation, ideally reducing financial costs and environmental strain. Emissions of carbon dioxide, a contributing component of global warming, would be reduced by burning less coal. At the same time, the university would be less dependent on out-of-state energy sources.

“This is the first project of its kind in the state,” says Pat Paustian, executive director of the Iowa Agriculture Innovation Center, Des Moines, IA. “It’s an excellent way to use waste products that might otherwise end up in a landfill.”

Iowa’s Biomass Fuel Project began in earnest in 2003 and had some initial setbacks. Considering that oat hulls burn more quickly than coal, facility services workers had to figure out how to inject the hulls at a different location than the coal. Additionally, a new silo needed to be installed to accommodate the hulls and deliver them to the pneumatic injection system. Most remarkably, the university’s agreement with Quaker Oats pioneered new ground in the field of sustainable energy production, which made it an even greater test.

“Nobody else at the time was burning oat hulls around here,” says Glen Mowery, director of utilities and energy management at The University of Iowa. “I would say our biggest challenge was to figure out material handling.”

Early costs related to modifying the power production system to accommodate the oat hulls totaled about $1 million. A new silo was put into place, and a recycling system was devised to prevent dust from escaping into the air as the oat hulls were loaded into the burners. However, that price tag quickly paid for itself as preliminary tests revealed that the venture was not only cutting down on material use - 30,000 tons of coal saved annually, along with 72,000 tons of carbon-dioxide emissions - but was also saving a lot of money for the university.

Now, the oat hulls are transported constantly from Cedar Rapids to Iowa City in trucks that can hold 22 tons each, says Joe Schwarzhoff, an engineer at The University of Iowa Power Plant. “The trucks carry 53-foot walk-in trailers, the largest you can have on the road,” he says. “They come in on 3-hour rotations, 24 hours a day, and load the oat hulls into our silo.”

That silo has a capacity to hold about 40 tons at once, and the power plant burns 7 to 8 tons of oat hulls per hour, which means that around 180 tons of the cereal-mill waste product are consumed per day. University officials have considered the idea of expanding the silo capacity to as much as 600 tons, according to Schwarzhoff.

A permanent permit to continue the oat hull project has been acquired from the Iowa Department of Natural Resources. The University of Iowa Power Plant, which serves 14.5 million square feet of building space, contains five boilers used for energy production. The goal for fiscal year 2006 is to use 74-percent coal, 15-percent biomass, and 11-percent natural gas. But officials would like to see biomass take a greater role at the plant.

“I’ve been very pleased with the oat hull project, and I’m looking forward to expanding it,” says Mowery. “Natural gas is very expensive these days, so we really want to expand renewable energy as much as possible.”

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