Band 7.5 IELTS Writing Task 1 Model Answer
Overall Band Score: 7.5 · Cambridge IELTS 12 · 2026-09-28
IELTS Writing Task 1 question
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.
Student answer (Band 7.5)
The diagram illustrates the process of generating electricity from geothermal energy using a power plant system.
Overall, the process is a five-stage continuous system divided into two main phases: a subterranean water-heating phase that reaches a depth of 4.5 km, followed by a surface phase where steam drives machinery to generate and distribute electricity.
In the subterranean phase, cold water stored at the surface is pumped down 4.5 km underground through an injection well. Upon reaching the geothermal zone, the water is heated as it flows through hot rocks. This heated water is subsequently pumped back up to the surface via a second shaft known as the production well.
During the surface phase, the hot water enters a condenser, which converts it into steam. This steam is then directed into a turbine, forcing it to spin. Driven by the motion of the turbine, a generator converts this kinetic energy into electrical power. Finally, the electricity produced is transmitted to the grid via high-voltage power pylons.
AI examiner evaluation
| Criterion | Band |
|---|---|
| Task Achievement / Task Response | 7.5 |
| Coherence and Cohesion | 7.5 |
| Lexical Resource | 7.5 |
| Grammatical Range and Accuracy | 7.5 |
| Overall | 7.5 |
Task Achievement / Task Response: Band 7.5
The student covers all parts of the task well, providing a clear overview and detailing the main stages of the geothermal energy production process. Key features, such as the 4.5 km depth, the injection and production wells, the condenser, the turbine, and the generator, are accurately identified and reported without major omissions. The progression of the process is fully developed and grounded in the visual data. The response meets all requirements for Task Achievement at a high standard, earning a Band 8.0.
Coherence and Cohesion: Band 7.5
The response exhibits a clear logical organisation and progression throughout. The introduction effectively sets out the scope of the process, followed by an overview paragraph. Subsequent paragraphs logically separate the subterranean phase from the surface phase. Cohesive devices are used flexibly and appropriately, such as 'Upon reaching', 'subsequently', and 'During the surface phase'. Paragraphing is used sufficiently and effectively to structure the report. Overall, coherence and cohesion easily meet the criteria for a Band 8.0.
Lexical Resource: Band 7.5
The student uses a wide and flexible range of vocabulary appropriate for an academic process description. Less common lexical items are used skilfully and naturally, such as 'subterranean', 'geothermal zone', 'condenser', and 'kinetic energy'. Word choice and collocations are precise throughout the text, with no noticeable errors. The lexical control demonstrated here easily satisfies the requirements for a Band 8.0.
Grammatical Range and Accuracy: Band 7.5
The response employs a wide variety of complex sentence structures with a high degree of accuracy. Excellent control is shown over subordinate clauses and participial phrases, as seen in 'Upon reaching the geothermal zone, the water is heated as it flows through hot rocks' and 'Driven by the motion of the turbine...'. The majority of sentences are entirely error-free, and punctuation is managed proficiently. This level of grammatical range and precision merits a Band 8.0.
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