A pump for a wastewater treatment plant has a motor with a nameplate rating of 20 HP. When the pump operates the measured power draw is equivalent to 15 HP. The pump operates 80% of the time. The energy company bills the plant at a rate of $0.15 per kilowatt-hour of energy used. Describe how to calculate the yearly energy cost for the motor. Assume the motor is 100% efficient. (Note also that 1 kilowatt-hour = 3,600 kJ although you don't necessarily need this conversion.)