• Large malt producer uses wood chips to fuel power plant

    Koda-Energy_LR_21by Gregg Hennigan

    If you drink beer, you’ve probably had one that Rahr Malting Co. helped make.

    That’s not an exaggeration. The Shakopee, Minnesota based company is one of the largest malt producers in the world and counts everyone from the biggest beer companies to small craft brewers as customers. Malt is germinated cereal grains used in brewing and distilling.

    As part of the manufacturing process, the Rahr production facility receives its heat and electricity from a biomass power plant operated by Koda Energy. The power plant is co-owned by Rahr Malting and a sovereign American Indian tribe called the Shakopee Mdewakanton Sioux Community (SMSC). For fuel sources, the Koda Energy power plant burns agricultural byproducts and organic material to generate the utilities. The average recipe for its fuel is 45 percent wood chips, 45 percent oat hulls, five percent malt and five percent barley. They burn up to 110,000 tons of dry wood waste each year in the form of wood chips produced by tub and horizontal grinders.

    Green solution

    Rahr Corp. was founded in 1847 and is still owned and operated by the Rahr family. Rahr Malting Co., a subsidiary, produces and distributes malt and industry related brewing supplies worldwide. Its operations in Shakopee, located southwest of Minneapolis, include one of the largest malt production facilities in the world. It consists of five individual malt houses and produces 418,878 tons of malt per year. The company has another malt house in Canada.

    The company says a $68 million expansion at the Shakopee campus scheduled to be complete in 2017 will make it the largest single site malting facility in the world. It will have the capacity to provide malt to brew six billion bottles of the average craft beer, or 12 billion cans of the average light beer.

    Before the Koda Energy power plant went online in 2009, the Shakopee campus was powered by natural gas. Natural gas prices are unpredictable. At the time were very high. So Rahr turned to biomass, which offered several benefits.

    First, biomass as fuel removed the price uncertainty brought by natural gas. In addition, the biomass power plant typically produced energy at a lower cost than natural gas. Another advantage is that the power plant provides a market for what otherwise would be waste products.

    “Moral of the story: No wood, no beer,” says Mike Marsollek, vice president of supply chain for Koda Energy. “People want to do business with them because they have a renewable energy plant,” Marsollek says. “I couldn’t put a value on that.”

    The malt and barley residues that Koda Energy burns are from the Rahr Malting process. The oat hulls are leftovers from cereal makers located in the area. The wood waste is primarily waste from municipalities and tree services, landscapers and pallet companies.

    As a result, the 23.4 megawatt power plant supplies all of the electricity and thermal energy for Rahr Malting. It also provides all of the electricity for Koda Energy’s operations. Additionally, it also sells about 12 megawatts of electricity to the grid through Xcel Energy.

    Electric Grinder fits philosophy

    The SMSC owns 51 percent of Koda Energy with Rahr owning the remaining 49 percent. The tribe’s involvement makes sense given the importance it places on the environment. It says its people have a kinship with Unci Maka, which translates as “Grandmother Earth.” The tribe is dedicated to protecting and preserving the environment.

    Koda Energy does not supply the SMSC with any power from the plant; however, the tribe does play an active role in the facility by supplying Koda Energy with approximately 60,000 tons of wood chips annually. Most of the wood chips are produced using a Vermeer TG5000E electric tub grinder that processes yard waste and material from tree service companies brought to the SMSC Organics Recycling facility. The use of an electric powered grinder complements the green philosophy of the involved parties.

    “Along with the consistency that we get out of the TG5000E electric grinder, it also fits the model of Koda Energy, the Shakopee Mdewakanton Sioux Community and Rahr Malting on renewable energy and keeping the environment clean versus burning diesel in our other grinders,” Marsollek says.

    The SMSC bought the electric powered grinder two years ago because of its energy efficiency and the minimal maintenance required on the electric motor. The grinder’s mill is powered with a 500 hp WEG fan cooled electric motor while it is designed with a separate 60 hp electric motor to power the pump for the hydraulic circuits. Two smaller electric motors power fans to cool the hydraulic system.

    “There are fewer moving parts to maintain,” says Al Friedges, manager of the SMSC Organics Recycling Facility. “You don’t have a diesel engine to deal with.”

    The Organics Recycling facility, where the TG5000E calls home, has grinding and composting operations that sit on 45 acres of tribal land just outside Shakopee, a few miles from Koda Energy.

    Meeting production needs

    The electric powered grinder’s environmentally friendly features would mean little if it didn’t produce a quality product. That hasn’t been an issue, however. Marsollek, who works closely with the SMSC, calls the electric grinder their “finished product grinder,” meaning it does the final grind before the wood chips are sent to Koda Energy.

    Koda Energy requires wood chips that are no bigger than three-quarters of an inch, have less than 14 percent moisture content and have less than one percent non-combustibles. Moisture content is particularly important. Hammermills in the Koda Energy plant grind the fuel into a fine powder, which is blown into a boiler. The high pressure steam that is generated is used to drive a turbine generator that produces the heat and electricity.

    If the wood chips put in the boiler are too wet, BTUs will be wasted drying them off, which increases costs. More importantly, the screen on the hammermill is 6/64 of an inch, and if the moisture content of the wood is above 14 percent, it is harder to grind and fails to keep pace with the demand of the boiler.

    “The TG5000E electric grinder has been crucial to the product coming to Koda Energy,” Marsollek says. “It’s very consistent, it’s very efficient to run, and we’d be remiss if we didn’t have that grinder out at the site.”

    It also keeps up with Koda Energy’s demand. The power plant can burn up to 11 tons of dry wood per hour, 24 hours a day and approximately 350 days a year.

    Koda Energy has other vendors that provide wood chips. Marsollek estimates about 80 percent of the chips used by the power plant come from Vermeer grinders.

    Reliability is essential for Koda Energy. If it didn’t get the fuel it needs, the power plant’s operations would be affected, and that in turn would have negative consequences for Rahr Malting and Xcel Energy.

    “We provide all of the thermal and all of the electrical to Rahr, plus 12 megawatts of electricity to Xcel Energy, which is enough to power about 20,000 homes,” Marsollek says. “We have contractual obligations with these guys. We cannot afford to not be in operation.”





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