A power grid has a load pattern during one 24-h period that averages 600 MW during 18 h and 1200 MW during 6h. A pumped-hydro energy storage system eith an elevation of 100 ft is considered. Calculate (a) the power output of a powerplant, in megawatts, that would meet the load demand with and without storage, and (b) the volume, in cubic feet, of water that must be pumped to meet storage demand. The elecrtic generator efficency is 0.8. Water density is 62.4 pounds per cubic feet