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Jesse Theis dips his hand into a vast, steaming bed of barley at the Rahr Malting plant in Shakopee and pulls out a kernel. He cracks open the flat, pea-sized husk and exposes the white, starchy flesh inside—the rudimentary component of beer. The sweet, fresh-cut-grass scent of germinating barley fills the air, as familiar to Theis as the Minnesota River Valley land his family has inhabited since 1846. Theis peers down at the kernel of grain and smiles. For 27 years, he has tended barley in the service of beer, producing malt for Anheuser-Busch, Miller, Summit, and Schell. Now, he will corral its energy to warm and light homes, power the malting facility, and, albeit indirectly, help clean up the polluted Minnesota River.
About 15 years ago, Theis explains, Rahr began looking for ways to generate the incredible amount of energy required to rotate vats of barley and heat kilns where the malted grain dries. The process takes up to 12 megawatts of power—enough to run the two ice arenas, nine restaurants, multiple water-treatment facilities, hotel and golf course, two casinos, and approximately 200 homes that lie on the Shakopee Mdewakanton Sioux Community reservation about seven miles away. Rahr has run on natural gas for years, but with prices steadily rising, the company wanted to find a more efficient, cost-effective way to generate power and heat.
Initial models focused on natural gas-powered heat-energy facilities. But in the very landscape surrounding the malting plant, Rahr found a more sustainable alternative.
Two hundred years ago, the Minnesota River Valley land where Rahr Malting now stands—30 miles southwest of St. Paul—was covered in woodlands, wetlands, and prairie. Settlers replaced the natural vegetation with farm fields, and now the valley is mostly farmland, primarily corn and soybeans. Urban development has taken off as well; Scott County was the fastest-growing county in the state from 2000 to 2007.
The changes have taken their toll on water and wildlife in the region, says Paul Nelson, land and resource manager for Scott County. With no protective cover of trees or prairie grass, there was nothing to absorb the rains and agricultural water flowing across the valley. Agricultural and urban runoff increased, and by the mid-1990s, the Minnesota River, a tributary of the Mississippi River that flows along the South Dakota border to Mankato and then northeast to St. Paul where it joins the Mississippi, had become one of the most polluted rivers in the country. Today, the river is cleaner, but runoff still cuts into stream banks, widens creek beds, deposits sediment, and damages habitat for fish and wildlife.
By 2000, Rahr had moved on to a vision of its dual heat-and-energy facility with the potential to help heal the landscape. Natural gas was out, and biomass—specifically, the barley byproducts left over from malting—was in. Theis reconnected with a University of Minnesota researcher he'd worked with as an undergraduate agronomy student 20 years before, and soon University scientists were into the project. Before long, Rahr had grant money, a business plan, and a new financial partner: the casino-rich Shakopee tribe.
Sixty years before, some members of the impoverished Indian community lacked electricity in their reservation homes. But by 2005, the tribe was wealthy enough to become the majority partner in the most innovative biomass energy project in the Midwest. With the partnership sealed, ground broke a year ago at the $55 million biomass facility, Koda Energy—its name taken from the Dakota word for friend. Its permit required the plant to be up and running by December 31.
Koda will be the first biomass facility in the nation to burn natural materials and nothing else, according to Joe Johannsen, Koda general manager. The first third of the materials will come from malting byproducts at Rahr, the second third will come from oat hulls leftover from production of things like Cheerios at a General Mills plant in Fridley, and the final third will come from natural wood and, eventually, prairie grasses.
The fuel will be burned in a 17-story suspension chamber heated to 1500-1700 degrees Fahrenheit; half of the 24-megawatt capacity will fuel Rahr and heat its barley kilns, and Koda will sell the remaining half to Xcel Energy at a profit.
Conservationists are thrilled that Koda will burn prairie grasses. That's because planting grasses could mitigate damage to the Minnesota River Valley and its water. Conservationist groups like the nonprofit Nature Conservancy, as well as the state Department of Natural Resources, the local soil and water conservation districts, and the U's scientists, hope that by creating a market for prairie grasses, Koda will convince farmers to plant their more sensitive lands—which lie along stream banks and erosion-prone hills—with native grasses rather than corn or soybeans. The grasses can help slow the flow of water across the land, as the trees and native prairie did before the region was populated.
Despite all its potential, growing prairie grass does have problems as a fuel source. Harvesting the grass could destroy the habitat it creates, so Rahr and Koda are working with wildlife biologists to peacefully co-exist. Prairie-grass advocates complain that state and federal policy now prohibits farmers from mowing sensitive areas. Plus, prairie grasses don't pay well compared to corn or soybeans.