Grand Coulee
Grand Coulee Dam is a conventional hydroelectric and pumped-storage facility in Grant County, Washington, comprising 33 operating generating units with 6,809 MW of combined nameplate capacity. The dam and all four of its powerhouses are owned and operated by the federal U.S. Bureau of Reclamation as the centerpiece of the Columbia Basin Project. Grand Coulee is the largest hydropower generating complex in the United States, a status secured in 1980 when the last unit of the Nathaniel "Nat" Washington (Third) Power Plant came online. That Third Power Plant alone contributes 4,485 MW from six large units, roughly two-thirds of the dam's total output, while the original Left and Right Powerhouses and the John W. Keys III Pump-Generating Plant supply the rest. The complex generates an average of about 21 billion kilowatt-hours a year and, beyond power production, provides irrigation water for the Columbia Basin Project, flood control, and streamflow regulation. No whole-plant or unit retirement is scheduled; the dam continues to operate under Reclamation, with its Third Power Plant currently undergoing a multi-year rehabilitation of all six units.