Band 6.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 6.5 · Cambridge IELTS 14 · 2026-08-05

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 6.5)

The diagram illustrates the process of electricity generation in a hydroelectric power station.

Water from the river is stored in a high-level reservoir behind a dam. During the day, the intake is open, and water flows down through a channel to the power station. As the water passes through reversible turbines, it drives the generator to produce electricity, which is then transmitted to the national grid via power lines. The used water then enters a low - level reservoir.

At night, when electricity demand is lower, the intake is closed. The reversible turbines switch function and act as pumps. They take water from the low-level reservoir and pump it back up to the high-level reservoir, ready for the next day's electricity generation.

This system effectively utilizes the gravitational potential energy of water to generate electricity, and the reversible turbines play a crucial role in both electricity production during the day and water recycling at night, making it a sustainable and efficient power-generation method.

AI examiner evaluation

Task Achievement / Task Response — Band 6.5

The response effectively covers all key stages of the hydroelectric process, including the distinction between daytime generation and nighttime water recycling. The main features are clearly identified, and the comparison between the two operational modes is well-integrated. The summary is accurate and follows the logical flow of the diagram. To reach a higher band, you could include more specific details from the diagram, such as the mention of the 'power lines' or the 'intake' mechanism more explicitly in relation to the dam structure, but overall, the task is fully addressed.

Coherence and Cohesion — Band 6.5

The response is logically organized, with a clear introduction and distinct paragraphs for the two operational phases (day and night). The progression of ideas is smooth, and the use of cohesive devices such as 'During the day', 'At night', and 'when electricity demand is lower' helps the reader follow the process easily. The final paragraph provides a concise summary of the system's function. The paragraphing is appropriate, and the flow between sentences is natural and coherent throughout.

Lexical Resource — Band 6.0

You have used a good range of vocabulary appropriate for a technical description, such as 'reversible turbines', 'gravitational potential energy', 'transmitted', and 'sustainable'. The terminology is accurate and used in the correct context. There is a good level of precision in your word choices, which allows for a clear explanation of the process. The vocabulary is sufficiently varied to describe the mechanical functions without being repetitive, demonstrating a good level of control over the subject matter.

Grammatical Range and Accuracy — Band 6.5

The writing demonstrates a high level of grammatical control. You have used a mix of simple and complex sentence structures effectively, such as the use of subordinate clauses ('when electricity demand is lower') and relative clauses ('which is then transmitted'). The punctuation is accurate, and there are no significant errors that impede communication. The majority of sentences are error-free, and the overall structure is sophisticated enough to convey the technical process clearly and accurately.

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

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