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 given diagram illustrates the process by which electricity is produced in a hydroelectric power station.

Overall

, it is evident that the process involved

water

flowing from a high-level

reservoir

to a low-level one, through reversible

turbines

which operate differently during the day and night. During the day, the first step takes place when

water

flows from a river to a high-level

reservoir

.

Subsequently

, it passes an intake valve which is open, flowing down to reversible

turbines

. After driving the

turbines

, electricity is generated and

then

transmitted to the national grid via power lines. The

water

then

continues its flow into the low-level

reservoir

.

Conversely

, at night the process is completely reversed. Whilst the intake valve is closed,

water

is pumped from the low-level

reservoir

back up by the reversible

turbines

, reaching the high-level

reservoir

once again.

This

procedure ensures the storage of

water

for the following day's consumption.

Consequently

, the circular operation ensures constant electricity generation by harnessing a natural resource.