Opportunities and barriers to pumped-hydro energy storage in the United States

As concerns about global warming grow, societies are increasingly turning to the use of intermittent renewable energy resources, where energy storage becomes more and more important. Pumped-hydro energy storage (PHES) is the most established technology for utility-scale electricity storage. Although PHES has continued to be deployed globally, its development in the United States has largely been dormant since the 1990s. In recent years, however, there has been a revival of commercial interests in developing PHES facilities. In this paper we examine the historical development of PHES facilities in the United States, analyze case studies on the controversies of disputed projects, examine the challenges to and conflicting views of future development in the United States, and discuss new development activities and approaches. The main limiting factors for PHES appear to be environmental concerns and financial uncertainties rather than the availability of technically feasible sites. PHES developers are proposing innovative ways of addressing the environmental impacts, including the potential use of waste water in PHES applications. In some cases, a properly designed PHES system can even be used to improve water quality through aeration and other processes. Such new opportunities and the increasing need for greater energy storage may lead policymakers to reassess the potential of PHES in the United States, particularly for coupling with intermittent renewable energy sources such as wind and solar power.