Band 5.5 IELTS Writing Task 1 Model Answer
Overall Band Score: 5.5 · Cambridge IELTS 14 · 2026-09-19
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 5.5)
The diagram illustrates how electricity is generated in a hydroelectric power station.
Overall, the process involves storing river water in a high-level reservoir and using its movement to generate electricity. The water passes through the power station, drives a generator, and then electricity is transmitted to the national grid.
At the power station, flowing water turns a turbine connected to the generator. The generator then turns the energy from the moving water into electrical energy. Finally, the electricity is carried through power lines and supplied to the national grid.
After passing through the turbine, the water flows into the low-level reservoir. During the period when electricity demand is low, the water can also be pumped back up to the high-level reservoir, allowing it to be used in the process.
AI examiner evaluation
| Criterion | Band |
|---|---|
| Task Achievement / Task Response | 5.0 |
| Coherence and Cohesion | 5.5 |
| Lexical Resource | 5.5 |
| Grammatical Range and Accuracy | 5.5 |
| Overall | 5.5 |
Task Achievement / Task Response — Band 5.0
The response successfully identifies the main features of the hydroelectric power station process, describing how water moves from the high-level reservoir, through the power station and generator, to the low-level reservoir. The overview provided in the second paragraph captures the core mechanism accurately. However, the student completely misses the crucial diurnal (day and night) cycle aspect of the diagram, omitting the contrast between daytime power generation and nighttime pumping back to the high-level reservoir through the reversible turbines. Furthermore, the response is under-length, containing only 129 words compared to the minimum requirement of 150 words. This under-length impacts the depth of coverage, resulting in an incomplete treatment of all visual details.
Coherence and Cohesion — Band 5.5
The text demonstrates a coherent overall arrangement and follows a logical sequence mirroring the physical flow of water from the reservoir to the grid. Paragraphing is used reasonably to separate the introduction, the generation process, and the water return phase. Cohesive devices are used adequately, with transition words such as 'At the power station', 'Finally', and 'After passing through the turbine' helping to guide the reader through the explanation. However, referencing and referencing markers are occasionally simplistic, and the overall progression feels somewhat disjointed due to the omission of the cyclical day/night mechanism which links the two reservoirs together structurally.
Lexical Resource — Band 5.5
The vocabulary used is generally adequate for the task, successfully incorporating topic-specific terminology such as 'hydroelectric power station', 'reservoir', 'turbine', 'generator', and 'national grid'. The student demonstrates the ability to use appropriate nouns and verbs related to energy production. However, the lexical range remains somewhat limited and repetitive, lacking more sophisticated or less common vocabulary items (such as 'conduit', 'diurnal cycle', or 'subterranean') that would elevate the response to a higher band. Word choice is generally natural, and spelling is accurate throughout the short text, causing no impedance to communication.
Grammatical Range and Accuracy — Band 5.5
The writer employs a satisfactory mix of simple and complex sentence structures, such as 'The water passes through the power station, drives a generator, and then electricity is transmitted' and 'During the period when electricity demand is low, the water can also be pumped back up'. Grammatical control is fairly strong, with the majority of sentences being accurate and error-free. Complex structures like relative clauses ('when electricity demand is low') are handled correctly. Punctuation is standard and appropriate. Minor slips are absent, but the range of complex structures is somewhat restricted, keeping this criterion at a solid functional level.
See this exact question answered at other band scores — the same prompt compared across bands.
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