The following diagram illustrates the process by which a hydroelectric power station generates electricity.
Overall, the power station is installed between two different levels of water so that the rotary piece of equipment can work as a turbine during the day to run the generator, and as a pump during the night to transfer water back to the high-level reservoir.
With regards to the day, the process begins by opening the intake to allow water to flow from the river to the rotary piece of equipment, causing the rotation of the shaft connecting it with the generator. Finally, electricity is transferred to the national grid through power lines.
Turning to the night, the intake is closed and the function of the rotary piece of equipment is reversed to pump water from the low-level reservoir to the high-level reservoir through the same pipe connections where water was flowing in the day.
