The Goldendale energy storage project is a 1.2GW closed-loop pumped storage hydropower station planned to be developed in Washington, US.
Estimated to cost £1.5bn ($2.1bn), the project was previously owned by a joint venture of Rye Development and National Grid.
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The fund management company Copenhagen Infrastructure Partners (CIP) acquired the ownership of the project in November 2020, while Rye will continue to lead the project until the start of construction activities.
The project was issued a preliminary permit by the US Federal Energy Regulatory Commission (FERC) in March 2018, while the final license application was filed in June 2020.
Scheduled to come online by 2028, the Goldendale energy storage project is estimated to have an operational life of more than 80 years. The facility is intended to supply renewable energy to the utilities in the Pacific Northwest and California.
Location and site details
The Goldendale pumped storage hydropower station will be built on a 681.6acre-site comprising private lands northeast of Portland and southwest of Kennewick, on the Columbia River, next to John Day Dam.
The pumped-storage facility will be primarily located in Klickitat County, Washington with transmission line extending into Sherman County, Oregon.
Goldendale energy storage project components
The Goldendale pumped storage project will have an underground powerhouse equipped with three Francis-type, reversible, variable-speed closed-loop pumped-storage power generating units of 400MW capacity each.
The units will be operating at a rated gross head of 2,360ft, while the maximum water discharge capacity is estimated to be 8,280 cubic feet per second.
The project will also comprise an upper and lower reservoir with a usable storage volume of 7,100 acre-feet, and an underground water conveyance tunnel.
The upper reservoir will have an ungated vertical intake structure covered with a hood to prevent vortex formation. The lower reservoir will be constructed as a horizontal intake concrete structure with steel slide glass gates that will allow isolation of tailrace tunnel from the lower reservoir.
The water conveyance system of the project will include a 29ft-diameter, concrete-lined vertical shaft, one 29ft-diameter, concrete-lined headrace tunnel, three 15ft-diameter steel-lined penstock tunnels, one 30ft-diameter concrete lined-tailrace tunnel, and three 20ft-diameter steel-lined draft tube tunnels, along with a slide gate which will be used to isolate pump-turbines from the lower reservoir.
Transmission details
The electricity generated power at the power station will be routed via 18/155kV intermediate step-up transformers housed in the transformer gallery located adjacent to the powerhouse to an outdoor 115/500kV substation and switchyard located near the lower reservoir.
The project will also connect with the John Day substation which is identified as the preferred connection point for interconnection by Bonneville Power Administration (BPA).
Water supply
Initial fill water and periodic make-up water required for the Goldendale energy storage project will be purchased from Public Utility District No. 1 of Klickitat County (KPUD) using a KPUD-owned conveyance system located adjacent to the project.
Electricity off-take
The potential commercial off-takers for the project include Puget Sound Energy (PSE), PacifiCorp, Los Angles Department Water & Power, and Tacoma Power.
Contractors involved
HDR Engineering prepared the initial design for the Goldendale energy storage project including covering the development points for gross pool size, turbine units’ energy storage, and plant efficiency.
