The Answer, My Friend: An electricity cooperative reuses a small commercial wind turbine—and edifies a community
The Maple Grove, Minnesota headquarters of Great River Energy (GRE) boasts myriad sustainable-design qualities, so many that the Perkins+Will–designed building was awarded LEED-Platinum certification last September—and that it appears in this month’s issue of Greensource as a COTE Top Ten winner. Those features range from inconspicuous to highly visible. In an example of the former, fly ash from one of GRE’s two coal-burning power plants replaced almost half of the cement in the 166,000-square-foot building’s concrete structural frame. Far more noticeable is the 97-foot-diameter wind turbine that is the office building’s most iconic feature.
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It, too, offers a case study in reuse. Originally installed in Holland, the Danish-manufactured NEG Micon M700 was sold to a party in Canada after it was replaced by a larger turbine. It was sold again to Gary, South Dakota–based Energy Maintenance Service, which prepped it for GRE: remanufacturing the gearbox; rewinding the generator for more efficient, one-speed operation in a lower wind regime; and repainting it to match GRE’s window frames.
Installing the M700 required a metaphorical greasing of wheels, too. Client and architect had studied government wind maps and performed other site analysis, and, in an arguable first, subjected a scale model of the project to wind-tunnel testing. Perkins + Will senior associate Doug Pierce, AIA, LEED AP, a sustainability strategist at the firm, explains that the wind-tunnel engineers “ran computational fluid dynamic models of turbulence off the buildings. That was important because we were in this semi-urban environment.”
When a few members of the city council, condemning the turbine as an eyesore, suggested placing it elsewhere, the GRE team tapped into its due diligence to allay concerns without sacrificing performance. And when a neighboring building expressed additional concerns, the charm offensive leapt back into action with shadow models, drawings comparing the M700 to Minneapolis high-rises and redwood trees, and an agreement to install additional ice-sensing brake systems on the turbine.
Today GRE renewable energy project leader Mark Rathbun is happy to report that GRE’s turbine is permitted, visible from several major roadways, and a budding icon for Maple Grove. (With all kinks smoothed, the machine should be working at 20 percent capacity factor this time next year and working in combination with an in-situ photovoltaic array to fulfill 15 percent of the GRE office’s electricity needs.)
“There are always misconceptions and misunderstandings with any new technology,” Pierce says of public acceptance of the M700. As more homeowners install small turbines for themselves, and companies like GRE source mid-size equipment from the secondary market, caution and educational campaigning should give way to easier embrace.
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