Complete list of operational and planned pumped storage power plants. Track interconnection queue requests across US ISOs and utilities, with daily data updates. The following page lists all pumped-storage hydroelectric power stations that are larger than 1,000 MW in installed generating capacity, which are currently operational or under construction. Those power stations that are smaller than 1,000 MW, and those that are decommissioned or only at a. Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing.