San Antonio Taps Quidnet Energy to Build Big Underground Battery
System will use pressurized water trapped between rocks to store energy.
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San Antonio will use pressurized water pumped underground to store energy on a scale most batteries can’t match, in a deal with Bill Gates-backed Quidnet Energy.
The firm is building “geomechanical pumped storage” for San Antonio’s CPS Energy utility, under a 15-year agreement for an initial 1 megawatts of storage and an option to expand to 15 megawatts. The system draws water from a holding pond, pumps it down a well to depths of 1,000 to 1,500 feet, and creates a pressurized reservoir trapped between rock layers. When electricity is needed, the water flows back to the surface to spin a turbine.