AURI ENERGY CENTER NEWS

STORIES BY DAN LEMKE

FUELING THEIR OATS
University of Minnesota shows favorable results testing emissions

Minneapolis, Minn. - Oat hulls could soon help warm the halls of the University of Minnesota’s Minneapolis campus.

U of M steam and electrical plant operators want to use more renewable fuels in their plants. The boilers in one plant are already designed to cogenerate power from coal and biofuels, as part of an energy and environmental upgrade completed five years ago. Faced with rising energy costs for 18 million square-feet of building space, officials designed more efficient systems with lower emissions at both St. Paul and Minneapolis campuses.

Wood is the only alternative fuel burned so far, as it was the only biofuel available in 1996 when the plant’s emissions permit was granted. Since then, the U of M has increased its wood consumption to about 32,000 million Btu - outpacing the local wood supply that meets its cogenerator’s specifications.

Because of erratic fuel supplies, fluctuating costs and original boiler-design intent, University officials have been seeking other biofuels to supplement the mix.

“We had tested a number of agricultural products for Btu value,” and knew that “many ag products compared favorably on cost ... compared to traditional fuels,” says Alan Doering, AURI technical services specialist. “But we didn’t have much information about emissions. The University has the capacity to measure emissions, so we were very interested in working together.”  

In early 2003, University officials negotiated a test burn with the Minnesota Pollution Control Agency to evaluate emissions using oat hulls. Emissions can vary by fuel source as well as technology and equipment used to burn them, making regulatory permitting difficult.

AURI’s coproducts utilization lab in Waseca helped produce hull pellets to address potential storage, dust and handling concerns, although they were not used in the actual test burns.  

The 35-percent oat-hull blend reduced sulfur-dioxide, carbon-monoxide and particulate emissions by nearly two-thirds over 100 percent coal. The blend did slightly increase nitrogen-oxide emissions, but well within permitted levels. The 9-percent oat blend showed a significant reduction in sulfur-dioxide and nitrogen-oxide emissions, but a slight increase in carbon-monoxide and particulate emissions - both well under permit thresholds.  

The University estimates it could burn 15,000 tons of oat hulls per year, and with new material-handling and burning equipment, up to 30,000 tons. Officials say General Mills’ two metropolitan-area plants could supply up to 60,000 tons of hulls year round.

 “Many other agricultural products have the potential to be used as biofuels. If the University can generate and share the emissions information we need, it will help improve the acceptance of ag products as viable fuels.”

AURI awarded Xcel Energy grant

AURI has been awarded a $760,000 grant from the Xcel Energy Renewable Development Fund to research coupling biodiesel with wind power to generate electricity. The institute will also participate in two other RDF-funded projects.  

AURI’s project is among 25 recommended for funding by an advisory board representing Xcel Energy and the Prairie Island Indian Community. The board reviewed more than 200 proposals. Almost $10 million was awarded to energy-production projects and another $12 million to renewable-energy research and development projects.  

The first phase of AURI’s project involves studying the economic feasibility of using biodiesel generators to power turbines when the wind isn’t blowing and to offset peak demand. The project’s second phase will include research on a field demonstration of wind and biodiesel electrical generation. Project partners include the Minnesota Soybean Growers, Northern Alternative Energy, Ziegler Caterpillar Services and the University of Minnesota.  

Scott Singelstad of the Minnesota Soybean Research and Promotion Council agrees it’s an opportunity to “expand biodiesel beyond a transportation fuel into a whole new market.”  

For another RDF project, AURI will provide information on Minnesota biomass supplies and opportunities to Coaltec Energy USA of Allendale, Michigan. Coaltec will use biomass such as poultry waste as solid fuel for a gasification testing facility. If tests burns are successful, the technology could be used by Xcel to benefit Minnesota’s poultry industry.

“The energy-production projects will benefit Minnesota consumers by providing economic sources of renewable energy,” says Dave Sparby, Xcel Energy vice president. Likewise, research and development projects will help “provide environmentally-sound and reasonably-priced energy in the future.”