Question –
WRITING TASK 1
You should spend 20 minutes on this task.
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.
Write at least 150 words.
Answer –
The diagram displays the process by which electricity is produced in a hydroelectric power plant.
Overall, it is an 8-stage, man-made, cyclical process. This process begins when water from a river is collected in a high-level reservoir of a dam and culminates in water from a low-level reservoir pumped back up to the high-level reservoir at night after it has been used to produce electricity.
Looking at the daytime process, first of all, water from the river is allowed to flow and is deposited in the high-level reservoir of a dam. After that, this water is sent towards a power station via a slanting pipe that is connected to an intake valve, which is kept open during the day. Once the water reaches the power station, it hits and rotates the reversible turbines which power the generator to which they are connected. The generator produces electricity, which is then transferred to a national grid via power lines. At the same time, the water gets stored in a low-level reservoir.
During the night, the reversible turbines, which were operating the generator during the day, now act as a motor that pumps the water stored in the low-level reservoir back up to the high-level reservoir so it can be reused the next day.