An innovative oat-hull project at the UI Power Plant energizes campus
Luck, location, and a little old-fashioned ingenuity have the University standing at the forefront of the state’s—and possibly the nation’s—renewable energy efforts.
Since early January, the UI Power Plant has been adding oat hulls to the coal it normally burns to produce energy, lowering the University’s energy costs and reducing harmful emissions into the atmosphere.
According to David Osterberg, associate professor of occupational and environmental health, no other public power plant in the state is so heavily engaged in the use of biomass materials for energy production.
“Wherever this happens across the United States, it’s uncommon to have 20 to 25 percent of all energy produced by wind or biomass or something that is not a fossil fuel,” Osterberg says. “This project is pretty substantial.”
The oat hull project began about a year and a half ago, with a phone call from Quaker Oats. The project promises to one day save the University about $500,000 a year.
The plant’s proximity to Quaker Oats, one of the world’s largest cereal producers, was a stroke of luck. Converting the UI plant to accommodate Quaker Oats’ discarded oat hulls required months of tinkering and planning, however.
“When I first heard about this, I said, ‘Bring ’em on down,’” Joe Schwarzhoff, process engineer at the Power Plant, recalls. “I thought it was going to be a bushel or two.”
Instead, the plant was inundated with several tons of oat hulls. Trucks are lined up almost daily outside the facility, waiting to unload their now-precious cargo.
“We’re burning about 60 tons per day right now, but we have reached a high of about 100 tons per day,” Schwarzhoff says.
Ultimately, the plan is to burn an average of 50,000 tons of oat hulls per year, which would reduce the University’s annual reliance on coal by about 25 percent.
The substitution also helps lower carbon dioxide emissions. Carbon dioxide, which contributes to global warming, is created when the carbon in a fuel source is ignited and mixed with oxygen in the air. Because the carbon in coal previously was underground, while an oat plant draws carbon dioxide—and oxygen—out of the air as it grows, burning oat hulls instead of coal prevents an increase in the global inventory of carbon dioxide.
Ferman Milster, associate utility director, says these advantages made it easy to accept Quaker Oats’ offer.
“I immediately recognized that burning biomass material has a very positive environmental impact and I saw an opportunity to reduce the University’s purchased-energy costs,” Milster says. “Plus, the money we pay for that fuel material stays in Iowa. Our natural gas and coal supplies come from out of state.”
Soon after the experiment began, however, Power Plant staff noted a few glitches. For one, the oat hulls began to ignite much too soon when they were added to the furnace at the same time as the coal. The premature combustion dramatically increased the temperature in some areas of the furnace and spread superfine dust throughout the plant.
Plant engineers decided to add the hulls to the combustion process at a later stage to keep temperatures down, and a new pneumatic injection system helps load the hulls into the furnace with less mess.
Now, the combustion system works great, but the oat hulls aren’t delivered fast enough to meet the UI goal of burning 50,000 tons per year. Milster and his staff are working with Quaker Oats to design new trucks and engineer a new on-site unloading system to expedite the delivery process.
The University also must obtain permits from the Iowa Department of Natural Resources and the U.S. Environmental Protection Agency to continue the project permanently. Right now, the test burns are being conducted on short-term experimental permits, with the regulatory agencies closely monitoring the process and atmospheric emissions.
Amazingly, the University has been able to accommodate these changes without increasing the size of its workforce. In fact, Milster says the plant has fewer operators than it did 12 years ago, largely due to an automated system that allows workers to operate boiler, turbine, and other plant equipment with the click of a computer mouse.
The new venture has been a win-win situation for the environment and Iowa’s economy, as well as for the University and Quaker Oats.
“I want to make this work here because it’s sound environmentally and sound economically for Iowa,” Schwarzhoff says. “This is good for the state.”
In fact, environmentalists have lauded the Power Plant for years because of its ability to provide heating, cooling, and electricity. The plant’s energy heats 100 percent of the campus, cools 50 percent of the campus, and meets 30 percent of campuswide electrical demand.
“In terms of energy efficiency, this is already a great plant,” Osterberg says. “The biomass project makes it a wonderful plant.”