If the useful power output of the plant is 80.0 mw, how much energy is absorbed per hour

Power is a dimension that expresses the amount of energy exerted or absorbed by a system by the given time. To determine the amount of energy absorbed, we simply have to multiply the energy by the number of time.

            Energy = (80 x 10^6 J/s)(1 h)(60 s/ 1 hr)

               Energy = 4.8 x 10^9 J

4.8 x 10^9 J

You get 6 for mechanical