Pumped Storage Hydropower in the United States: Emerging Importance, Environmental and Social Impacts, and Critical Considerations

ABSTRACT Pumped storage hydropower is a widely used, long‐duration energy storage system that sits squarely at the water‐energy nexus. Bold decarbonization goals have propelled a rapid resurgence of interest in pumped storage hydropower in the US, given its ability to provide bulk energy storage, manage grid reliability, and support increasing integration of variable renewable energy sources. Drawing on published research from both technical and social science perspectives, this paper provides an overview of pumped storage hydropower technology, the project development pipeline, potential social and environmental impacts, including a comparison of open‐loop and closed‐loop design configurations, and critical considerations for project development. In contrast to all existing pumped storage hydropower projects in the US that are open‐loop and located on natural water bodies, this review finds that over 80% of proposed projects are closed‐loop designs, due to their siting flexibility away from natural water bodies and purportedly lower social and environmental impacts. However, issues around projects, including concerns over permitting and consultation processes and conflicts over siting, water resources, and Indigenous lands, are emerging more frequently given the planned expansion of projects in the arid US West and near Tribal lands. These issues and conflicts are not necessarily lowered by closed‐loop technology. The early stage of project development offers an opportunity to design projects that include community input and minimize tradeoffs. In turn, this will require taking a critical look at each pumped storage hydropower project as well as understanding community perceptions and the lifecycle impacts of this technology.