Band 7.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 7.5 · Cambridge IELTS 14 · 2026-09-20

IELTS Writing Task 1 question

The diagram below shows how electricity is generated in a hydroelectric power station.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

Student answer (Band 7.5)

The diagram illustrates the operation of a hydroelectric power station, showing how electricity is generated during the day and how water is pumped back into the high-level reservoir at night.

Overall, the process consists of two alternating stages. During the day, water flows from the high-level reservoir through reversible turbines to generate electricity, before being discharged into the low-level reservoir. At night, the direction of the water flow is reversed, allowing the water to be pumped back to the high-level reservoir for use during the following day.

During the day, the intake at the dam is opened, allowing water from the high-level reservoir to flow down through a channel towards the power station. As the water passes through the reversible turbines, they operate the generator, which produces electricity. The electricity is then transmitted through power lines to the national grid. After passing through the turbines, the water is discharged into the low-level reservoir.

At night, the process operates in the opposite direction. The intake at the dam is closed, and water from the low-level reservoir flows back through the reversible turbines. In this stage, the turbines operate as pumps, forcing the water upwards through the channel and back into the high-level reservoir. This stored water can then be used again during the following day, making the process continuous and renewable.

AI examiner evaluation

Task Achievement / Task Response — Band 7.5

The student fully addresses all parts of the task by accurately summarising the main features of the hydroelectric power station diagram. The overview is clear, effectively highlighting the two alternating day and night stages of the process. All key stages—from the high-level reservoir, intake, reversible turbines, generator, and power lines to the national grid and low-level reservoir—are reported accurately and supported by details from the diagram. No data is invented or misread, demonstrating a strong understanding of the visual information. The response satisfies all requirements of Band 8 for this criterion.

Coherence and Cohesion — Band 7.5

The response is logically sequenced and easy to follow. Progression is clear, moving naturally from an introductory overview to the daytime process and finally the nighttime cycle. Paragraphing is used appropriately, with each paragraph focusing on a distinct aspect of the diagram. Cohesive devices such as 'Overall', 'During the day', 'At night', and 'After passing through' are used effectively without being intrusive. Referencing is clear throughout, ensuring smooth transitions between ideas. This meets the standards for a Band 8 in Coherence and Cohesion.

Lexical Resource — Band 7.5

The student uses a sufficient and appropriate range of vocabulary suitable for describing a technical process. Terms such as 'alternating stages', 'discharged', 'reversed', and 'transmitted' demonstrate flexibility and precision. Less common lexical items related to the diagram, such as 'reversible turbines', 'national grid', and 'conduit' (implied via channel), are handled well. Word choices and collocations are accurate, with no noticeable spelling or word-choice errors. The lexical control displayed aligns comfortably with a Band 7.5 to 8.0 descriptor profile, justifying a solid Band 8.

Grammatical Range and Accuracy — Band 7.5

The student demonstrates a wide range of grammatical structures with a high level of accuracy. Complex sentences are used naturally, incorporating participial phrases ('showing how electricity is generated', 'making the process continuous') and subordinate clauses effectively. The majority of sentences are error-free, and control over punctuation and tense consistency is strong. Minor slips are virtually absent. This level of grammatical control meets the criteria for Band 8.

See this exact question answered at other band scores — the same prompt compared across bands.

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