Band 6.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 6.5 · Cambridge IELTS 14 · 2026-09-03

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 how electricity is generated in a hydroelectric power station through a reversible process involving two reservoirs.

Overall, electricity is produced during the daytime when water flows from the upper reservoir through reversible turbines to the lower reservoir. At night, the process is reversed, with the turbines functioning as pumps to return water to the upper reservoir for reuse.

This operation is a reversible process. At first, water from the river goes to a high-level reservoir and finally reaches to the dam, which is opened during the day and closed at night. Then the water travels through a pipe and reaches the reversible turbines to generate electricity. In mornings those turbines act as a operate generator to produce power; the generated electricity is sent to the national grid from the power station with the help of power lines. Then the water in the turbines is flushed out to the low-level reservoir.

Whereas, at night time the whole process is reversed. Now the turbines act as pumps to pump water from low reservoir to high level reservoir, and the water starts travelling in the opposite direction. As mentioned the dams will be closed at night time so the water travels back, again to restart the whole process.

AI examiner evaluation

Task Achievement / Task Response — Band 6.5

The response successfully identifies the main features of the hydroelectric power station process. You have clearly distinguished between the daytime power generation phase and the nighttime pumping phase. The overview is effective and provides a clear summary of the reversible nature of the system. However, there are some inaccuracies in the description of the process; for instance, stating that water from the river goes to a high-level reservoir 'at first' is slightly confusing, as the diagram implies a closed-loop system between two reservoirs. Additionally, the mention of 'mornings' is not supported by the diagram, which specifies 'daytime'. Despite these minor points, the key stages are covered well, and the comparison between the two modes of operation is clear.

Coherence and Cohesion — Band 6.5

The essay is logically organized with a clear introduction, an overview, and two body paragraphs detailing the two distinct phases of the process. Paragraphing is used appropriately to separate the daytime and nighttime operations. Cohesive devices such as 'Whereas', 'Then', and 'At first' are used to guide the reader through the sequence of events. While the flow is generally good, some transitions feel slightly mechanical, and the referencing could be more precise in places. Overall, the information is presented in a coherent manner that is easy to follow, meeting the requirements for a Band 7 score.

Lexical Resource — Band 6.0

You have used a sufficient range of vocabulary to describe the technical process, including terms like 'reversible turbines', 'national grid', 'power lines', and 'reservoir'. There is some evidence of less common lexical items, which helps in conveying the process accurately. However, there are some minor inaccuracies in word choice, such as 'act as a operate generator' (should be 'act as a generator') and 'flushed out', which is not the most precise term for water flowing into a reservoir. Despite these small slips, the vocabulary is adequate to convey the meaning clearly and demonstrates a reasonable level of flexibility.

Grammatical Range and Accuracy — Band 6.0

The response displays a mix of simple and complex sentence structures. You have successfully used passive voice constructions, which are appropriate for describing a technical process. There are some grammatical errors, such as 'reaches to the dam' (should be 'reaches the dam') and 'act as a operate generator'. Additionally, there are minor issues with article usage and verb forms. However, these errors are infrequent and do not impede communication. The majority of your sentences are clear and error-free, showing a good level of control over basic and some complex grammatical forms.

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

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