Band 7.0 IELTS Writing Task 1 Model Answer

Overall Band Score: 7.0 · Cambridge IELTS 14 · 2026-09-14

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 7.0)

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

Overall, the process involves the movement of water between a high-level reservoir and a low-level reservoir. During the day, water flows downhill through turbines to generate electricity, while at night, the water is pumped back to the high-level reservoir for reuse.

During the daytime, the intake is opened, allowing water from the high-level reservoir to flow through a pipe towards the power station. As the water passes through reversible turbines, they operate a generator, which produces electricity. The electricity is then transmitted through power lines to the national grid. At the same time, the used water flows into the low-level reservoir.

At night, the process is reversed. The intake at the dam is closed, and the reversible turbines work as pumps. Water from the low-level reservoir is pumped back through the pipes to the high-level reservoir. This prepares the water for the next daytime cycle, when it can once again flow down and generate electricity.

AI examiner evaluation

Task Achievement / Task Response — Band 7.5

The response successfully covers all parts of the task by clearly summarising the main features of how electricity is generated in a hydroelectric power station. The introduction accurately paraphrases the prompt, and the overview captures the essential dual-phase process involving day and night cycles between the high-level and low-level reservoirs. Key features such as the intake, the pipe, the reversible turbines, the generator, the national grid, and the low-level reservoir are all integrated logically into the description. The information is well-selected, accurate according to the diagram, and makes clear comparisons and transitions between the daytime generation phase and the nighttime pumping phase, aligning well with the Band 8 descriptor.

Coherence and Cohesion — Band 7.5

The response is logically organized with a clear overall progression. It begins with a general overview paragraph, followed by a detailed description of the daytime generation phase, and concludes with the nighttime reversal phase. Cohesive devices are managed effectively throughout the text, utilizing temporal and transitional markers such as 'Overall', 'During the day', 'At the same time', and 'At night'. Paragraphing is used sufficiently and appropriately, separating the distinct stages of the diagram into clear thematic units. Referencing and substitution, such as 'The electricity is then transmitted' and 'At night, the process is reversed', ensure that the flow of information remains smooth and natural, easily meeting Band 8 requirements.

Lexical Resource — Band 6.5

The student demonstrates a sufficient and flexible range of vocabulary suited to a process diagram. Appropriate technical and semi-technical terms are employed, including 'hydroelectric power station', 'reservoir', 'reversible turbines', 'generator', 'national grid', and 'pumps'. Word choices are precise, and collocations are generally natural, such as 'flows downhill', 'pumped back', and 'daytime cycle'. While there are no major lexical errors, the vocabulary is somewhat standard for this task type without showcasing a vast range of highly sophisticated uncommon lexical items, which places it firmly at a solid Band 7 level.

Grammatical Range and Accuracy — Band 6.5

The student displays a good control of grammar and punctuation, utilizing a healthy mix of simple and complex sentence structures. Complex clauses are integrated smoothly, as seen in 'As the water passes through reversible turbines, they operate a generator, which produces electricity.' The majority of sentences are error-free, and punctuation is handled correctly throughout the text. Minor issues, such as the slight antecedent mismatch in 'As the water passes through reversible turbines, they operate', do not impede communication. The control of tense and voice, particularly the passive constructions required for describing a process, is handled accurately, matching the Band 7 criteria.

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