Cambridge IELTS 12 Test 8 Writing Task 1
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.
Geothermal power plant
The diagram displays how a geothermal power station generates electricity.
Overall, the station produces electricity in five main steps: pumping cold water underground, heating it, pumping heated water to the surface, converting it into steam, and using the steam to turn the turbine to create electricity.
First of all, cold water stored in the container is pumped down to the injection well that is 4.5 kilometers deep beneath the Earth’s surface. The well then injects the water into the geothermal zone where it is heated by hot rocks.
The superheated water is subsequently pumped above ground and into the condenser. Here, its pressure is lowered, which turns it into steam. As the steam passes through the turbine, it drives its blades to rotate. The spinning turbine then powers the generator connected to it to create electricity. Finally, the electricity generated is delivered to the power grid through power lines.
The Wrong Way to Write the Overview
Only summarizing the first and last steps is not enough. Please read the examiner’s comment on page 133 of Cambridge IELTS 16. Besides, although the diagram doesn’t show, the process is actually cyclical and so doesn’t end.
❎ Overall, the production of geothermal power is a man-made process, beginning with pumping cold water underground and end with using steam to turn the turbine to create electricity.
There is an error in the diagram. Whatever the thing is in Step 4, it clearly isn’t a condenser. A condenser turns steam into water through cooling. It does not turn water into steam. However, we have to describe what the diagram depicts, so this cannot be helped. Just be careful not to write that the condenser brings down the water’s temperature because water turns to steam when you increase its temperature. Use “lower the pressure” instead: the condenser lowers the waters’ pressure and turns it into steam.