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

The diagram outlines the

process

of

electricity

production in a hydroelectric

power

station

. The

process

begins when the

water

flows

from the

river

into a high-level

reservoir

and ends with the transmission of

electricity

to the national grid. In general, the

process

is broadly distributed into

day

and

night

stages with the daylight stages involving

electricity

production from a

river

and storage of

water

in a

reservoir

. At

night

, the

water

flows

back in the opposite direction towards an initial

reservoir

and the

river

. The

day

stage of the

process

involves channelling the

river

water

into a high-level

reservoir

backed up by a dam. There is an intake area leading to the

power

station

that opens during the

day

and closes at

night

.

Water

flows

during the

day

to generate

electricity

through the

power

station

turbines. The generated

electricity

is

then

sent to a national grid through

power

lines

while

the excess

water

runs to a low-level

reservoir

. During the

night

stage, the

water

stored in the low-level

reservoir

is reverted to the

power

station

and the turbines of the generator pump it back into the high-level

reservoir

which is closed during the

night

. The

river

water

is stored at the upper level and later it

flows

down, starting the cycle again.