IELTS Academic Writing Task 1/ Graph Writing – Diagram/ Process Diagram:
You should spend about 20 minutes on this task.
The diagram below shows how geothermal energy is used to produce electricity.
Summarise the information by selecting and reporting the main features, and make comparisons where relevant.
Write at least 150 words.
Model Answer:
The diagram illustrates how a geothermal power plant harnesses underground heat (also known as geothermal heat) to produce electricity.
Overall, the process has five major stages: cold water injection, heating the water using geothermal heat, pumping heated water to the surface, steam generation, and finally, electricity production using a turbine.
In the first phase of this process, cold water stored in a surface reservoir is pumped down through an injection well that reaches approximately 4.5 kilometres beneath the Earth’s surface. This deep well carries the water into a geothermal zone composed of very hot rocks, where the water absorbs geothermal heat and becomes superheated. Next, this heated water travels upward via a production well to the surface, where it is routed into a condenser. In the condenser, the pressure is lowered, causing the hot water to convert into steam. This steam then flows toward a turbine, causing its blades to spin rapidly. The rotating turbine drives a connected generator, thereby producing electricity, which is then delivered to the power grid through power lines.