Figure P1-33 illustrates a pumped-hydroelectric storage system. During a 12-hr period at night when the demand for electricity is low, electrical motor-driven pumps transfer water from the lower reservoir to the higher reservoir. During the 12-hr period in the daytime when the electrical demand is high, water from the upper reservoir is discharged through turbines to generate electrical power for the grid. The mean water temperature is 20°C. The motors/pumps are 71 percent efficient, and the turbines/generators are 90 percent efficient. If 1,000,000 m3 per 12-hour period are involved, analyze the system to determine the cost of the process if the energy cost is $5 per million kJ. What is the energy loss per kWh of power generated?