The diagram illustrates the process of generating electricity in a hydroelectric power station.
The process begins with the flow of water from a river into a high-level reservoir, controlled by a dam.
During the day, water is released from the reservoir through an intake, which is kept open, allowing water to flow downward through pipes to a power station. The kinetic energy of the flowing water drives the generator, which produces electricity and is supplied via power lines to the national grid for distribution.
At night, the process is reversed. The intake is closed, and water from the low-level reservoir is pumped back to the high-level reservoir using reversible turbines. This turbine works as a pump, moving the water uphill, ready to be used again during the day for electricity generation.
Overall, the hydroelectric power station operates in a cyclical manner, generating electricity during the day and conserving energy by pumping water back to the high-level reservoir at night.