Yes, pump motors and generators. so 96% motor and 96% pump up = are in the 95-7% efficiency, pumps about the same up or down. So .96 x .96(up) and .96 x .96 (down) = 84.9% and friction drops that a little. It is quite good if you hacve a handy high dam pond to use as many places do. To build a high dsm pong may not be economic unless you have a topographic valley you can dam and fill (and murder all the locals and flying snapping turtles) Dams have many objectors, so new ones are hard to build, except for China.