Academic Writing Task 1 · process diagram

The process of generating electricity using a geothermal power plant

The process below shows how electricity is generated with the help of water.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant. Write at least 150 words.

Geothermal power plant electricity generation process

1.Cold water is stored at the surface
2.Cold water is pumped down a 4.5 km injection well
3.Water travels through the geothermal zone of hot rocks
4.Hot water is pumped up through the production well
5.Steam is produced and directed into a condenser
6.Steam powers a turbine which drives a generator to produce electricity

Chart redrawn by BandLadder from the data in the original IELTS practice task. Many IELTS practice tasks come from the Cambridge IELTS series (Cambridge University Press & Assessment); all rights in the original tasks remain with their owners.

Band 8 sample answer

The provided diagram illustrates the various stages involved in generating electricity through a geothermal power plant. Overall, the process is a continuous cycle that relies on the thermal energy of underground rocks to convert cold water into steam, which subsequently drives a turbine to produce electrical power.

Initially, cold water is stored at the surface before being pumped down into the earth. This water travels through an injection well to a depth of 4.5 kilometres. Upon reaching the geothermal zone, the water is heated by the surrounding hot rocks. Once heated, the water is then pumped back up to the surface through a production well.

In the final stages, the hot water is converted into steam, which is directed into a condenser. This steam provides the necessary energy to power a turbine. The turbine is connected to a generator, which is activated by the turbine's rotation to produce electricity. This electricity is then transmitted via power lines for distribution. The entire system functions as a cyclical mechanism, utilising the earth's natural heat to generate sustainable energy.

176 words. Every figure in the answer comes from the chart above.

How to write about process diagrams

Say how many stages there are and where the process starts and ends.
Use the passive and sequencers: first, after this, once, finally.
Keep every stage; a missing step costs task achievement.

illustrates: shows or makes clear by using a diagram
subsequently: happening after something else in a sequence
utilising: making practical and effective use of something
cyclical: occurring in a series of repeating stages
subsequently: happening after something else in a sequence
consequently: as a result or effect of something

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Frequently asked questions

What should the overview say?

The process illustrates a closed-loop system where cold water is heated by underground geothermal energy to produce steam, which is then converted into electricity.

How long should an IELTS Task 1 answer be?

At least 150 words; 170 to 200 is the safe range. Spend about 20 minutes on it and leave 40 for Task 2, which carries twice the marks.

How do I describe process diagrams?

Say how many stages there are and where the process starts and ends. Use the passive and sequencers: first, after this, once, finally. Keep every stage; a missing step costs task achievement.