Name of the Project
Goldendale Energy Storage project.

Location
South-east of Goldendale, Klickitat County, Washington, US.

Project Owner/s
Energy infrastructure investment company Copenhagen Infrastructure Partners.

Project Description
Goldendale is a closed-loop pumped-storage hydropower project with two reservoirs linked to an underground powerhouse and transmission system.

The development includes an upper and lower reservoir; an underground water conveyance between the upper reservoir, powerhouse and lower reservoir; access tunnels; an underground-to-overhead transmission line, a substation/switchyard; and supporting infrastructure. 

The upper reservoir will consist of a 23-m-high, 2 438-m-long concrete-faced rockfill embankment and will be concrete-lined to limit seepage. Water will enter through an ungated “morning-glory” intake-outlet – a circular, open intake that drops into a vertical shaft connected to a tunnel system, allowing for the controlled transfer of water between reservoirs during generating and pumping cycles. 

From there, water will be conveyed to the underground powerhouse through a 671 m vertical shaft, a 1 006 m high-pressure headrace tunnel, a 61 m manifold tunnel and three 183 m penstocks. 

The underground powerhouse cavern will house three 400 MW Francis-type pump-turbine units, providing 1 200 MW of installed capacity. Discharge to the lower reservoir will occur through three 61 m draft tube tunnels, a 61 m low-pressure tunnel and a 975 m tailrace tunnel.

The lower reservoir will be impounded by a 62-m-high, 1 859-m-long concrete-faced rockfill embankment and double-lined geosynthetic liner plus waterproof concrete, with drainage and leak detection.

Initial filling water will be supplied from Klickitat public utility district through a new valve and a buried 76 cm steel conduit to the lower reservoir. Power will be stepped up from 18 kV to 115 kV underground, then to 500 kV at a new outdoor substation, and tied into the network, reaching the John Day substation through existing 500 kV lines. 

The plant will provide 12 hours of energy storage.

Potential Job Creation
The project will support more than 3 000 family-wage construction jobs and as many as 70 full-time operational jobs.

Capital Expenditure
Not disclosed.

Planned Start/End Date
The project is expected to enter commercial operation in 2031/32.

Latest Developments
The US Federal Energy Regulatory Commission issued 40-year licence to the project in February 2026.

Key Contracts, Suppliers and Consultants
None disclosed.

Contact Details for Project Information
Golden Energy Storage, email info@goldendaleenergystorage.com.