Answer: Using 1 kilowatt hour of electricity to pump water and then produce electricity will almost certainly be less than 1 kilowatt hour of electricity.
The work of the water pump converts electrical energy into mechanical energy (potential energy) of water. Power generation converts the mechanical energy of water into electrical energy.
According to the law of conservation of energy, during the operation of motors and generators, the mechanical efficiency is less than 1 and there are various energy losses. The final electrical energy obtained will be permanently reduced.
Since electrical energy cannot be stored, excess electrical energy will be wasted if not used. When electricity consumption is low, excess electricity is used for water storage by pumping, thereby improving the electricity utilization rate.
The construction of large-scale reservoirshelle for water and energy storage also requires significant investment, which is completely different from pumped hydroelectric energy storage.