Some electric-power companies use water to store energy. Water is pumped by reversible turbine pumps from a low to a high reservoir. To store the energy produced in 1.0 hour by a 115 MW (115 106 W) electric-power plant, how many cubic meters of water will have to be pumped from the lower to the upper reservoir? Assume the upper reservoir is 600 m above the lower and we can neglect the small change in depths within each. Water has a mass of 1000 kg for every 1.0 m3. This problem has completely confused me. How do I do this?