Question
Answer
The diagram depicts a hydroelectric power station, and shows how electricity is generated by the
flow of water through a dam and other component parts. Ultimately, water flows from one reservoir
to another, producing electricity that is sent to the national grid.
Firstly, water enters a reservoir from a river. The water is held back from its natural course by a dam,
underneath which there is an intake pipe that is open during the day and closed at night. During the
daytime, water flows down, via gravity, to the power station, which is housed below the dam. In the
power station, the flowing water spins a generator, which produces an electrical current that is then
distributed via power lines to the national grid.
Once the water has generated this electricity, it flows into a lower reservoir, but at night it is
pumped back up through the system to the upper reservoir, ready to begin the process again the
following day.
