Academic Writing Task 1: Practice Test- 3 | IELTS Mock Tests & Practice Tests PDF Download

You should spend about 20 minutes on this task.
The diagrams below show a structure that is used to generate electricity from wave power. 
Summarise the information by selecting and reporting the main features and make comparisons where relevant.
Write at least 150 words.
Ans:
The given illustrations present how electricity is generated using the power of the sea.
Overall, through a specially designed structure, a green source of electrical energy can be produced by the constant movement of the sea, which forces air through a chamber.
As seen in the first image, the man-made structure must be built next to a sea wall or cliff so that its foundation is strong enough to withstand the powerful waves. There is a specially constructed chamber, possibly built from a combination of metal and concrete, that allows seawater to flow in and out. The chamber leads into a column where a turbine is suspended. When a wave flows into the chamber, the water forcefully pushes the air out of the column. As the strong rush of air travels upwards, it pushes past the turbine, causing it to rotate quickly. It is this mechanical movement of the turbine that generates electricity.
As shown in the second picture, when the wave recedes, air refills the chamber, allowing the process to continue as the waves will keep entering and exiting the chamber, making the turbine spin continually. The result is a sustainable source of electrical energy.