Band 8.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 8.5 · Cambridge IELTS 12 · 2026-07-29

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 8.5)

The diagram illustrates the process by which electricity is generated using geothermal energy.

Overall, the production of electricity involves five main stages. The process begins with cold water being pumped deep underground, where it is heated by hot rocks, and ends with electricity being generated after steam powers a turbine.

Initially, cold water is pumped from the surface to a depth of approximately 4.5 kilometres through an injection well. Once underground, the water passes through the geothermal zone, where it flows between layers of hot rocks. As a result, the water absorbs heat and becomes hot before being forced back to the surface through a separate production well.

In the next stage, the hot water enters a condenser, where it is converted into steam. This steam is then directed towards a turbine, causing its blades to rotate at high speed. The rotating turbine is connected to a generator, which converts the mechanical energy into electrical energy. Finally, the electricity produced is supplied for use, completing the geothermal power generation process.

AI examiner evaluation

Task Achievement / Task Response — Band 8.5

The response effectively addresses the task requirements by providing a clear overview of the geothermal energy process. You have successfully identified the main stages, from the injection of cold water to the final generation of electricity. The information is accurate and covers all key features shown in the diagram. The inclusion of specific details, such as the depth of 4.5 kilometres, demonstrates a good grasp of the provided data. The summary is well-structured and follows a logical sequence, which helps the reader understand the process clearly. To reach a higher band, ensure that you explicitly mention the cyclical nature of the process if the diagram implies it, but overall, this is a very strong performance.

Coherence and Cohesion — Band 8.5

The response is logically organized, with a clear introduction, a body paragraph detailing the process, and a smooth flow between stages. The use of cohesive devices such as 'Initially', 'Once underground', 'In the next stage', and 'Finally' is effective and helps guide the reader through the chronological steps of the process. Paragraphing is used appropriately to separate the overview from the detailed description. The progression of ideas is smooth, and referencing is clear throughout the text. There is no evidence of mechanical or repetitive use of linking words, making the text easy to follow and coherent.

Lexical Resource — Band 8.0

You have used a sufficient range of vocabulary to describe the technical process accurately. Terms such as 'geothermal zone', 'injection well', 'production well', 'condenser', and 'mechanical energy' are used correctly and demonstrate a good command of topic-specific language. The vocabulary is precise and appropriate for an academic report. There are no significant errors in word choice or collocation. While the range is adequate, incorporating a few more sophisticated synonyms or varied descriptive verbs could further enhance the lexical variety, but the current usage is already quite strong and natural.

Grammatical Range and Accuracy — Band 8.5

The response displays a good variety of complex sentence structures, such as the use of passive voice ('is generated', 'is pumped', 'is converted') which is highly appropriate for describing a technical process. The grammar is accurate throughout, with very few, if any, errors. Punctuation is used correctly to manage complex sentences. The majority of the sentences are error-free, and the control over tense and subject-verb agreement is consistent. The writing is fluent and demonstrates a high level of grammatical competence, which is well-suited for this type of academic task.

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