You should spend about 20 minutes on this task.
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.
Write at least 150 words.
The diagram illustrates the process of electricity that is generated in a hydroelectric power station.
As can be seen from the diagram，the water in high-level reservoir，which comes from the river，flows to generate electricity via the intake under the dam only open in the day time. Besides，the water passes into the power station where the generator is operated the reversible turbines. Next，the electricity that is generated moves to the national grid by the power lines. Moreover，the water in the day time goes into the low-level reservoir. In the night time，the water is pumped into the high-level reservoir by the same reversible turbines from low-level reservoir for the flow of water during pumping which passes into the high-level reservoir in the dam in which the intake is closed.
To sum up，a hydroelectric power station generates power，based on different height of water level，using the natural water energy in the day time and transferring the water to create and store the energy for the next day in the night time.