Band 9: 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.

The diagrams illustrate how electricity is generated from sea waves using a special structure installed near a cliff or sea wall.

Overall, the system produces electricity by using the movement of waves to force air through a chamber, which causes a turbine to rotate. Importantly, the turbine continues spinning in the same direction during both stages of the process.

In the first stage, when a wave enters the chamber, the water level rises inside the structure. As a result, the air above the water is pushed upward through the column. While the air passes through the column, it causes the turbine to rotate, generating electricity.

In the second stage, the wave moves away from the chamber, causing the water level to fall. Consequently, air is drawn downward through the column. Although the airflow changes direction, the turbine continues rotating in the same direction. Therefore, electricity is still produced during this stage of the process.

Overall, the structure allows electricity to be generated continuously by using both the incoming and outgoing movement of sea waves