A University of Iowa renewable energy project is using woody biomass to stimulate the local economy.

The Oakdale Renewable Energy Plant, led by Ferman Milster, principal engineer, has replaced one of four coal boilers used to provide steam for a satellite campus with a wood chip-fired unit manufactured by Hurst Boiler and Welding Co.

The boiler will produce 20,000 pounds per hour of saturated steam. Milster and his team have repurposed an old underground coal bunker to serve as wood chip storage, and, according to Milster, the team is excited about the opportunity to procure even more of the biomass fuel locally. “All the natural gas and coal to support our energy needs comes from out-of-state,” he said. “That means the money for this fuel leaves Iowa. Buying wood chips locally, at prices competitive with historical average natural gas prices, puts money back into the local economy.”  

Part of that local biomass-based economic stimulus will come from the facility’s future needs for biomass. The plan calls for 40 percent of all energy used on the main campus to be renewable. Since 2003, the campus has used anywhere from 9 percent to 13 percent renewable energy. Although a 40 percent goal will be difficult, Milster said there are already plans in place to make the use of biomass a major part of that renewable energy initiative. The school has formed a biomass partnership project with participants from the Iowa Department of Natural Resources, the U.S. Fish & Wildlife Service, National Conservation Resources Service, Iowa State University, the University of Northern Iowa and the Iowa Flood Center. Interested private land and business owners including forestry equipment manufacturers are also involved, he said. “The partnership is developing procurement, transportation, storage and handling plans to support a significant expansion in local biomass fuel procurement over the next several years,” he added.

The Oakdale facility is using woody biomass sourced from an Iowa sawmill, but in the future, Milster said other sources of biomass from dedicated growth areas on marginal land, timber stand improvement areas or invasive species harvested areas in wetlands will all be used. The cost of the delivered biomass is roughly $48.50 per ton, and Milster said the team has been running at 40 percent moisture, which he calculated equates to $5.50 per million Btu. Since planning for a biomass boiler started in April 2009, Milster said his team has gained a better understanding of biomass in Southeastern Iowa in addition to its past history of cofiring oat hulls with coal at a power plant located on the main campus. Material handling systems at the Oakdale facility include a walking floor in the wood chip storage area, screw conveyors, bucket elevators and drag chain conveyors. The boiler also features state-of-the-art pollution controls including a ceramic baghouse that Milster said should exceed the new boiler MACT standards.

A research gasification unit has also been installed and syngas created by the unit is fed into the new boiler. In addition to syngas research, Milster said his team has a lot to learn. “We will learn to work with local vendors and contractors to supply the wood chip fuel,” he said, adding that it will hopefully provide more value to a byproduct from the local timber industry.

In July 2010, the University received nearly $1 million in funding that, in addition to the biomass boiler conversion, included other projects related to power generation through anaerobic digestion.