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 shows the process behind the production of electrical energy in a hydroelectric power station. An overview of this image tells us that this is a two-fold process. The plant consists of two dams- one at a higher altitude and another at the lower end. During the day the plant produces electricity and by evening, it uses a part of its power to pump water back into the higher dam. Throughout the day, a large volume of water flows from the high-level reservoir to the turbine located at the lower end of the power plant. The force of the liquid turns the blades of the turbine, which in turn, powers the generator. Thus, producing electricity, which is then sent to the national grid using electrical cables. Furthermore, the spent water is collected in a dam at a lower ground level. During the night, the turbines run in the opposite direction and pump the fluid back into the high-level reservoir. Hence, the generator works as a motor that assists in this transfer. This cycle continues and keeps generating electrical energy.