FERC issues mine pumped storage guidance, list of potential projects

Implementing a 2018 federal law designed to facilitate the development of new facilities capable of storing electric energy, U.S. regulators have issued guidance to assist applicants for licenses or preliminary permits for closed-loop pumped storage projects at abandoned mine sites. The Federal Energy Regulatory Commission also issued a list of existing non-powered federal dams that the Commission and other agencies agree have the greatest potential for non-federal hydropower development.

A pumped storage facility can consume electricity to pump water from a lower reservoir to an upper reservoir, from which the water can flow back down through turbines to recover most of the stored energy. In a closed-loop configuration, the reservoirs are constructed features (such as surface mine pits or underground mines), rather than natural waterways, lakes, or wetlands. While battery storage capacity is increasing rapidly, pumped storage represents the vast bulk of U.S. electricity storage capacity, with about 40 projects contributing about 22 gigawatts of capacity.

In 2018, President Trump signed the America's Water Infrastructure Act of 2018 into law. The law amended several portions of the Federal Power Act which govern how the Federal Energy Regulatory Commission issues preliminary permits and licenses for hydropower projects. It also contained specific provisions requiring the Commission to establish expedited processes for issuing and amending licenses for qualifying facilities at existing nonpowered dams as well as for closed-loop pumped storage projects.

Based on the potential for development of abandoned mine sites into pumped hydropower storage facilities, the law also required the Commission to hold a workshop to explore potential opportunities for development of closed-loop pumped storage projects at abandoned mine sites, and to issue guidance within one year to assist applicants for licenses or preliminary permits for closed-loop pumped storage projects at abandoned mine sites.

On October 17, 2019, the Commission issued its Guidance for Applicants Seeking Licenses or Preliminary Permits for Closed-Loop Pumped Storage Projects at Abandoned Mine Sites, in Docket No. AD19-8-000. This 49-page document provides basic information on pumped storage, abandoned mines in the U.S. (of which there are as many as 500,000), and licenses and preliminary permits for closed-loop pumped storage projects at abandoned mine sites. It also reviews best practices and considerations, including typical environmental issues, site selection considerations, and regulatory processes.

Separately, the Commission also issued a list of 230 non-powered federal dams, sorted by potential capacity, identified by the Commission and the Secretaries of the Departments of the Army, the Interior, and Agriculture as having the greatest potential for non-federal hydropower development. Facilities included on the list range from the Melvin Price Locks & Dam on the Mississippi River (listed as having 299.3 megawatts of potential capacity), down to dozens of dams with less than 2 megawatts of potential.