The diagram illustrates how electricity is generated in a hydroelectric power station.
Overall, the process involves two different phases: one during the day, when electricity is produced and transmitted to the national grid, and another at night, when water is pumped back to the reservoir for reuse.
To begin with, during the day, water from the river is stored in a high-level reservoir, which is held back by a dam. When the intake is opened, the water flows downward through a pipe towards the power station. The force of the moving water drives reversible turbines, which in turn operate a generator. The electricity produced is then transmitted via power lines to the national grid. After passing through the turbine, the used water is discharged into a low-level reservoir.
At night, the process is reversed. The intake is closed, and the turbines work in reverse to pump water from the low-level reservoir back into the high-level reservoir. This prepares the system for the next cycle of electricity generation during the day.