The Federal Energy Regulatory Commission on Aug. 22 granted a preliminary permit to the Grand Coulee Project Hydroelectric Authority for a pumped storage hydro project that would generate 1,000 MW or 1,040 MW, depending on final project configuration.
This is the proposed Banks Lake Pumped Storage Project No. 14329, to be located on Banks Lake and Franklin D. Roosevelt Lake, near the town of Grand Coulee, in Douglas and Grant counties, Wash. The project would be located on federal lands administered by the U.S. Bureau of Reclamation.
A preliminary permit gives a party a 36-month, exclusive right to look at the feasibility of a hydro project, with a license application then needed if the decision is to proceed with the project.
The authority proposed two alternatives for its pumped storage project. Alternative No. 1 would use Banks Lake as the upper reservoir and Roosevelt Lake as the lower reservoir. Alternative No. 2 would use Banks Lake as the lower reservoir and involve construction of a new upper reservoir. Both Roosevelt Lake and Banks Lake are components of the Columbia Basin Project, and are connected by a feeder canal that provides water for twelve pumps operated by the Bureau of Reclamation at the John W. Keys III Pump Generating Plant.
- Under Alternative No. 1, the project would include: a reservoir inlet/outlet structure at Banks Lake equipped with trashracks; a 1.5 mile-long penstock consisting of a vertical shaft, power tunnel segments, and a tailrace section, extending between the Banks Lake inlet/outlet and the reversible turbine/generator units in the powerhouse; either an underground powerhouse containing four reversible turbine/generator units rated for 250 MW each, for a total installed capacity of 1,000 MW, or a powerhouse located on the shore of Roosevelt Lake, also containing four 250 MW reversible turbine/generator units; and a 2 mile-long, 500-kV transmission line extending from the powerhouse to an existing 500-kV substation. The estimated annual generation of Alternative No. 1 would be 2,263 gigawatt-hours (GWh).
- Alternative No. 2 includes: a 312-acre upper reservoir, located about 3,000 feet west of Banks Lake, impounded by three earth and rockfill embankments, each with a crest elevation of 2,300 feet above mean sea level; an upper reservoir inlet/outlet structure equipped with trashracks; a 620-foot-long, 43-foot-diameter vertical shaft connecting the upper reservoir inlet/outlet structure to the power tunnels; four 1,700-foot-long, 17-foot-diameter power tunnels leading from the vertical shaft to the powerhouse; an underground powerhouse containing four reversible turbine/generator units rated for 260 MW each, for a total of 1,040 MW; a 25-foot-diameter tailrace tunnel between the powerhouse and the Banks Lake; and a 2.4-mile-long, 500-kV transmission line extending from the powerhouse to a new 500-kV substation. The estimated annual generation of this alternative would be 2,978 GWh.