A subsea tidal turbine array has a mean electrical power output of 34.5 MW34.5\text{ MW}34.5 MW, which is sufficient to power 15 00015\,00015000 deep-ocean exploration units.
Calculate the mean power supplied to each exploration unit. Give your answer in watts.
Some of the kinetic energy from the tidal flow is wasted as thermal energy due to friction in the rotating shafts and viscous drag on the turbine blades. Engineers apply a low-friction polymer coating to the rotating shafts and streamline the blade profiles.
Explain how these modifications affect the efficiency of the tidal turbines.