Meijer Inc. has installed six rooftop wind turbines at its headquarters in Michigan. The 1.5-kilowatt turbines will provide some of the energy needed to power the four-story building. "What we are trying to do is take a small step and set an example," a Meijer spokeswoman said. "The actual generation of power is not the top reason for doing it." The company plans to install rooftop units on two of its stores in other area cities after they develop appropriate zoning rules.