New Analysis Reveals Pumped Storage Hydropower Has Low Global Warming Potential

Researchers analyzed the life cycle greenhouse gas impacts of energy storage technologies and found that pumped storage hydropower has the lowest global warming potential on average.

Water Power Technologies Office

March 14, 2024
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Hydropower Program

Grid Reliability, Resilience, & Integration (HydroWIRES)

Project Name: PSH Characterization and Capacity Expansion Model Enhancements

Project Team: National Renewable Energy Laboratory

Lead Recipient Location: Golden, Colorado

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Researchers from the National Renewable Energy Laboratory (NREL) conducted an analysis that demonstrated that closed-loop pumped storage hydropower (PSH) systems have the lowest global warming potential (GWP) across energy storage technologies when accounting for the full impacts of materials and construction. 

PSH is a configuration of two water reservoirs at different elevations. Closed-loop PSH reservoirs are not connected to a naturally flowing water feature (like a river) and use a turbine/pump and generator/motor to move water between reservoirs and generate electricity. Though PSH has been around for more than 100 years, limited information is available about greenhouse gas emissions associated with its use. 

The findings from NREL's study, reported in the journal Environmental Science and Technology, provide a life cycle assessment of new closed-loop PSH in the United States and assess its GWP. 

A photo of two water reservoirs with mountains behind them.

A National Renewable Energy Laboratory analysis found that closed-loop pumped storage hydropower systems have the lowest global warming potential across energy storage technologies when accounting for the full impacts of materials and construction.

Photo by Bryan Bechtold and Josh Bauer, National Renewable Energy Laboratory

Researchers based their findings on 39 preliminary designs from 35 proposed closed-loop PSH sites in the contiguous United States. The base scenario also assumed the electricity mix would entirely come from renewable technologies. Researchers found that PSH, on average, offered the lowest GWP when compared to compressed-air energy storage, utility-scale lithium-ion batteries, utility-scale lead-acid batteries, and vanadium redox flow batteries. 

These results demonstrate that enabling renewable electricity deployment by adding PSH to the grid will result in lower climate change impacts and contribute more to achieving the country's clean energy goals compared to other grid-scale energy storage technologies.