Pumped Hydro Compressed Air Energy Storage (PHCAES) is a new system that can deliver stored energy at two to three cents per kilowatt-hour. This cost, far lower than that of lithium batteries, is similar to Pumped Hydro Energy Storage (PHES), a proven technology. Although it has many similarities to PHES, PHCAES has significant advantages over PHES — including lower capital costs and significantly less land space required.
Like PHES, PHCAES uses a ground-level water reservoir and a power plant. The difference is in the pressure reservoirs.
