The diagram below shows how electricity is generated in a hydroelectric power station. Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

The illustration demonstrates the process by which energy is harnessed to produce electricity in a hydroelectric power station. Overall, the process consists of two stages, electricity generation during the day and pumping of water during the night. Beginning with the daylight stage, after the water flows from a river, it is collected into a high-level reservoir behind a dam. The dam’s intake is opened during the day and the water flows to the reversible turbines of the power station, which in turn power a generator to which they are connected. This generator produces electricity, which can be subsequently transmitted to the national grid through the power lines. Moreover, the water continues to flow into a low-level reservoir. During the night, the water is pumped back up from the low-lever reservoir via the reversible turbines into the high-level reservoir. Furthermore, the intake is closed at night and the water is collected to the high-lever reservoir.