Information Study for Pumped Storage Hydropower Siting

Identifying and understanding the issues and interests surrounding the siting of pumped storage hydropower (PSH) in Washington state is necessary if this proven technology is to be used to help achieve the state’s greenhouse gas emission limits, transition off fossil fuels, and reduce the impacts of climate change.

Washington State University invites Tribes and stakeholders such as local governments, land use and environmental organizations, and other interested parties to participate in a process to share their issues, concerns, and interests about the location of PSH in the state.

This is an information gathering process only – there are no PSH projects being proposed or reviewed.

What is Pumped Storage Hydropower

Pumped storage hydropower acts as a battery by storing energy and releasing it when demand for electricity is high. It consists of two water reservoirs at different elevations. When energy is needed, water flows from the upper reservoir to the lower reservoir through turbines that generate electricity which is sent to the electrical grid. Water is pumped from the lower reservoir back up to the upper reservoir (recharge) when there is an excess supply of power. PSH can provide energy at times when solar and wind resources fluctuate, such as at night or when winds are weaker, thus improving grid resiliency which is important for the transition toward renewable energy.

PSH is a mature and proven long-duration storage technology that can provide up to 12 hours or more of electricity.1 As of 2022, PSH provided approximately 96% of the energy storage capacity in the United States, mostly from projects built decades ago.2 Its technology process is mechanical, so it does not rely on critical mined minerals such as lithium. Drawbacks of PSH include a long construction period, specific site needs of elevation differences for the reservoirs, and possible impacts of land, environmental, and other resources. While they are expensive to build, they are long lasting making their life-cycle cost lower than most other battery technologies due to its long lifespan.

The WSU study focuses on closed-loop PSH, where neither reservoir is connected to an existing water body. Most of the existing PSH plants are open loop, with the lower reservoir using water from a river or other water source. Closed-loop PSH has fewer impacts to wildlife, habitats, and the hydrologic cycle.


The information process is written into the Washington State Legislature 2023 Engrossed Second Substitute House Bill 1216 (Section 306) ,3 concerning clean energy siting, and signed into law May 3, 2023 effective July 23, 2023. The legislature directs the Washington State University Energy Program to conduct a process to identify issues and interests related to siting pumped storage projects in Washington state in order to support expanded capacity to store intermittently produced renewable energy. The bill states that “The goal of the process is to identify and understand issues and interests of various stakeholders and federally recognized Indian tribes related to areas where pumped storage might be sited, providing useful information to developers of potential projects, and for subsequent environmental reviews under the state environmental policy act.” WSU is to “provide ample opportunities for the engagement of federally recognized Indian Tribes, local governments and special purpose districts, land use and environmental organizations, and additional stakeholders that self-identify as interested in participating in the process.” WSU will also include non-federally recognized Tribes in the process.

Our process

Listening to as many people as possible is key to provide information back to the legislature. In addition to three or four facilitated gatherings across the state, we plan to meet with Tribal staff and others who would like more targeted meetings, hold informational webinars, and provide ways to comment and give feedback online. The larger facilitated gatherings will occur from September through December 2024, and they will be in-person with a virtual option. Locations and precise dates will be announced when known.


Researchers from the National Renewable Energy Laboratory (NREL) created a map showing possible locations for PSH projects in the United States, using various parameters such as existing elevation data and economic factors. WSU is working with a GIS consultant who is reviewing and assessing this data for Washington state, and identifying other data and factors unique to Washington that will further refine locations. Some data identified during the Least-Conflict Solar Siting on the Columbia Plateau project4 may be used, however the goal of the PSH siting information process is to gather interests and concerns about PSH siting, not to create a mapping tool as was one of the outcomes of the Least-Conflict study.

How can you participate?

Sign up here for our PSH Siting email distribution list to receive updates and information about meeting dates and locations. Please let other individuals and groups who may be interested in participating know about this process.

1The amount of energy this amounts to depends on the rate of discharge and the maximum rating of the system.
2U.S. Hydropower Market Report 2023 Edition
3 Laws/House/1216-S2.SL.pdf

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