Band 7.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 7.5 · Cambridge IELTS 14 · 2026-09-21

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 system functions as a reversible cycle between a high-level reservoir and a low-level reservoir. During daytime hours, electricity is generated using water flow, while at night, water is pumped back up to prepare for the next day's operation.

During the day, river water flows into the high-level reservoir behind a dam. An intake valve opens, allowing water to flow downward through a large channel towards the power station. The force of the downward water drives reversible turbines, which operate a generator to generate electricity. This electricity is then transmitted via power lines to the national grid. After passing through the turbines, the water is held in a low-level reservoir.

At night, the process reverses. The intake valve at the upper reservoir is closed. The reversible turbines operate in reverse to pump water from the low-level reservoir back up through the pipe into the high-level reservoir. This ensures the high-level reservoir is replenished for the following day's power generation cycle.

AI examiner evaluation

Task Achievement / Task Response — Band 7.5

The student has successfully covered all main stages of the hydroelectric power station process diagram, providing a clear and accurate summary of both daytime and night-time operations. The overview accurately captures the core mechanics of the system as a reversible cycle between the high-level and low-level reservoirs. Key features such as the river inflow, dam, intake valves, reversible turbines, generator, power lines, and national grid are all appropriately integrated and described without any factual inaccuracies or misreadings of the visual data. The response fully satisfies the requirements of Academic Task 1, earning a strong band score.

Coherence and Cohesion — Band 7.5

The response exhibits a clear logical progression from the introduction to the overview, and subsequently through the chronological and cyclical stages of the day and night operations. Paragraphing is used very effectively to separate the distinct phases of the process (daytime generation versus night-time pumping). Cohesive devices such as 'During the day', 'After passing through', and 'At night' are employed naturally to guide the reader smoothly through the sequence of events without feeling mechanical. Referencing throughout the text is clear and appropriate.

Lexical Resource — Band 7.5

The student demonstrates a wide and flexible vocabulary well-suited to describing technical processes. Less common and precise items such as 'reversible cycle', 'replenished', 'conduit' (implied via channel/pipe), and 'transmitted' are used accurately. Collocations and word choices are natural, for instance, 'drives reversible turbines' and 'power generation cycle'. There are no noticeable spelling or word-choice errors, enabling the reader to comprehend the technical information effortlessly.

Grammatical Range and Accuracy — Band 7.5

A wide range of grammatical structures is used effectively, including complex sentences with subordinate clauses ('An intake valve opens, allowing water to flow downward...'). The majority of sentences are completely error-free, showing excellent control over tense consistency (present simple is used appropriately throughout for a process description) and punctuation. Minor slips are virtually absent, and the grammatical execution comfortably 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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