A new report from researchers at the National Renewable Energy Laboratory (NREL) identifies sites in the US that could support pumped storage hydropower plants as well as highlighting how much they might cost and how much energy they could produce. A further report (being published soon) uses that data set and additional resources to examine how hydropower’s low-cost, flexible energy could support tomorrow’s grid. 

Until now, little data existed on where pumped storage hydropower plants could be built in the United States.  In 2017, the Australian National University developed a data set of potential pumped storage hydropower sites around the world, identifying about 616,000 potential locations. Now, a team of researchers have adapted the university’s original algorithm to create more detailed geospatial data on potential sites in the United States.

Screenshot of a topological map of the United States with dots showing potential pumped storage hydropower sites. Data visualization by NREL

Researchers from both the Australian National University and NREL had to make some technical design decisions up front. Each reservoir, for example, needs a dam. And both dams could have an infinite number of potential heights.

“You can imagine,” said Stuart Cohen, a model engineer at NREL and a co-author on both reports, “how that problem explodes if you have an infinite number of choices.”

To rein in their data set, NREL’s researchers fixed parameters like dam height and storage duration, selecting a 10-hour energy storage duration, for example, because it tends to be more cost competitive (for comparison, today’s batteries provide about 4 hours of energy storage). Using their geospatial algorithm, the team searched the country for all possible sites and then pared those down into a final list that adhered to additional technical, environmental, and economic considerations. To find the best spot, any hydropower aficionado can then sort and filter those sites by head height (the difference in elevation between the two reservoirs), energy capacity, and cost.

While the first data release relies on these fixed parameters, soon Cohen and team plan to build an updated version of their map that gives users more control. “We want to build an interactive map where you can check boxes on and off to choose between 12-hour or 8-hour storage, 40-meter or 60-meter dam height. Whatever people want.”

Then, once a developer locates a site, the tool can estimate how much their plant might cost to build. Also based on the Australian National University’s original model, NREL’s cost model is adapted for financial and economic conditions in the US, so developers can evaluate whether to build their plant (or not).

The work has been funded by the US Department of Energy’s Water Power Technologies Office, and is part of its Hydro Water Innovation for a Resilient Electricity System Initiative (HydroWIRES).

A new, one-of-a-kind dataset identifies sites for closed-loop pumped storage hydropower across the United States, including Alaska, Hawaii, and Puerto Rico. Here, the colored hexagons identify mountainous areas that hold the greatest future potential for these clean energy storage facilities. Photos from Stuart Cohen, NREL