The diagram illustrates the process of electrical power production in a hydroelectric plant. The process differs between the day and night and necessitates the building of a high-level reservoir, a low-level reservoir and a power plant.
Firstly, water is collected in a reservoir which is built higher than the power plant. The water originates from a river and is held in the reservoir by a dam.
During the day, the dam is opened to allow water to flow rapidly through the turbines in the power station, causing them to rotate. As a result, the energy of the turbines’ movement is converted into electricity, which then supplies into the national grid via power lines. Meanwhile the water is collected in another reservoir that is built at a lower height than the dam.
During the night, the water in the low-level reservoir is pumped back into the first reservoir, driving the turbine to rotate in the opposite direction compared to the day.