All that is true. There are inefficiencies every time energy is converted from one form to another -- in this case, from mechanical to electrical, then electrical back to mechanical.

Typically, the most efficient any deep-well turbine pump will ever be is about 84% efficient -- that is, for the power consumed by the pump, you will get no more than about 84% of the theoretical work being done lifting water to the surface.

Three-phase motors are about 92 to 94% efficient, if the power factor is corrected properly.

Generators... well, that's a whole 'nother story. A diesel engine is only about 40% efficient, at best. The generator won't be any more efficient than a motor, so reckon on 90%+ of the mechanical energy put into the generator ending up as power.