Band 7.5 IELTS Writing Task 1 Model Answer
Overall Band Score: 7.5 · Cambridge IELTS 14 · 2026-09-15
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 process of generating electricity in a hydroelectric power station during the day and night.
Overall, the process consists of a two-stage cycle. During daytime hours, water flows downward from a high-level reservoir to power turbines and generate electricity for the national grid. At night, the system operates in reverse, pumping water back up to the higher reservoir for reuse.
During the day, water flows from a river into a high-level reservoir behind a dam. The intake gate at the base of the dam remains open, allowing water to flow down a pipe into the power station. As the water passes through, it rotates reversible turbines that drive a generator. The generated electricity is then distributed to the national grid via power lines. After driving the turbines, the water discharges into a low-level reservoir.
At night, the operation reverses direction. The intake gate at the dam is closed, stopping downward flow. The reversible turbines act as pumps, drawing water back from the low-level reservoir through the power station and up the pipe into the high-level reservoir. This replenishes the water supply, ensuring the system can repeat the generation cycle the following day.
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 has fully addressed all parts of the task by providing a clear and accurate summary of the hydroelectric power station diagram. The response successfully covers both phases of the cycle—daytime electricity generation and nighttime water pumping—without missing any major details. The overview provided in the second paragraph effectively outlines the two-stage cycle as requested. All descriptions of the visual data, including the role of the dam, intake gates, reversible turbines, generator, and reservoirs, are accurately reported and grounded in the source diagram. No data is invented or misread, demonstrating a high level of task fulfillment that meets the Band 8 criteria.
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 to the nighttime reversal. Paragraphing is used appropriately, with distinct paragraphs dedicated to the introduction, overview, daytime stage, and nighttime stage. Cohesive devices such as 'During the day', 'As the water passes through', 'After driving the turbines', and 'At night' are managed well to guide the reader through the sequence of events. Referencing is consistently clear, resulting in a cohesive piece of writing that fits comfortably into the Band 8 descriptor for this criterion.
Lexical Resource — Band 7.5
The student demonstrates a wide and flexible lexical range suitable for an academic process description. Appropriate subject-specific vocabulary is used accurately, including terms such as 'hydroelectric power station', 'reversible turbines', 'national grid', and 'replenishes'. Less common vocabulary and collocations are handled skilfully, as seen in phrases like 'system operates in reverse', 'discharges into', and 'stopping downward flow'. Word choice and spelling are entirely accurate throughout the response, showing a high degree of lexical control that satisfies the requirements for Band 8.
Grammatical Range and Accuracy — Band 7.5
The text exhibits a wide range of grammatical structures, successfully blending simple sentences with complex forms containing participial phrases ('allowing water to flow down', 'ensuring the system can repeat') and relative clauses. The majority of sentences are completely error-free, and control over grammar and punctuation is consistently strong. There are no noticeable slips or awkward constructions that impede communication. This level of syntactic variety and accuracy fully corresponds to a Band 8 performance.
See this exact question answered at other band scores — the same prompt compared across bands.
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