In early 2011, Bechtel completed the largest lump-sum turnkey project in its history, the Oak Creek power plant expansion in eastern Wisconsin. Built for Wisconsin Energy, the plant, with two coal-fired steam-turbine generating units and related civil works, sits next to the existing Oak Creek power plant on the west shore of Lake Michigan. The expansion provided enough energy to power more than 1 million households.
The Oak Creek expansion is among the most efficient coal-fired power systems in the world, in part because of its innovative cooling system. Rather than using cooling towers, in which water recirculates from condensers to the cooling tower and back, sending heat into the air, Oak Creek uses a more efficient “once-through” cooling technology. A tunnel 9,200 feet (2,800 meters) long and 26 feet (eight meters) in diameter carries water from Lake Michigan into the plant’s condensers and then back to the lake, taking the heat from the turbine exhaust with it (see Detail Design).