The San Luis Pumping-Generating Plant (also known as the William R. Gianelli Power Plant) is situated between O'Neill and San Luis Reservoirs and can pump water uphill for storage in San Luis during period of low demand, and release it during periods of high demand. The plant has eight reversible Francis turbine units which can generate up to 424 megawatts when releasing water. The power consumption while pumping is 376 megawatts. The maximum water flow while generating is , and maximum pumping is .