FERC staff on Oct. 30 issued the final environmental assessment for a proposed 5 MW pumped-storage hydro project on the Columbia River, concluding its potential environmental impacts, with "appropriate" protective measures, would not "significantly affect the quality of the human environment."
Shell Energy North America's open-loop Hydro Battery Pearl Hill project [P-14795] would be sited about 7 miles upstream of the U.S. Army Corps of Engineers' 2,069 MW Chief Joseph Dam (WPW No. 13 ; 14 [5.5]). It is designed to provide regulation and spinning reserve for supporting grid reliability in the region, according to Shell's application.
Pearl Hill would have 5 MW of generating capacity, 9 MW of pumping capacity and storage of up to 30 MWh of energy. Average annual generation is estimated to be 24 GWh.
The generating and pumping equipment would be housed on the east shore of Rufus Woods Lake, the reservoir created by Chief Joseph Dam.
Shell would use the lake as the lower reservoir and construct a tank on the plateau 1,300 feet above the lake for the upper reservoir. The reservoirs would be connected by a 6,100-foot-long penstock.
A 2,500-foot-long, 24.9 kV transmission line would run from the project's substation adjacent to the lower reservoir to a Douglas County PUD distribution line on the plateau.
Construction is expected to take between six and nine months to install the tank, penstock and platform for the equipment housing.