The diagram below shows how electricity is generated in a hydroelectric power station.
Sample Response
The process shows how electricity is generated in a hydroelectric power station. In general, the diagram can be broadly separated into day and night stages with the daylight stages involving the generation of electricity from a river and storage of water in a reservoir. At night the water flows back in the other direction towards the high-level reservoirtowards an initial reservoir and the river. The daytime phase begins withThe first stage of the process involves channelling the river into a high-level reservoir formed by a dambacked up by a dam. There is an intakean intake area leading to the power station that is open during the day and closes at night. Water flows during the day to generate electricity through the power station turbines and the resulting electricity is sent to a national grid through power lines while the water then continues to a low-level reservoir. The reversible turbines that operate the generator during the day allow the station to pump the water in the low-level reservoir back into the high-level reservoir for use the next day.
Why this response received Band 7.5
The response gives a clear, accurate account of the full daily cycle, with a particularly effective overview of daytime generation and nighttime pumping. Its main limitation is occasional imprecision, especially the suggestion that water returns toward the river, and some stages are compressed into long sentences. Prioritize sharper directional wording and separate the generation and return phases more distinctly.
IELTS Writing Criteria Scores
Task Achievement
The overview identifies the two operating periods and the response accurately covers nearly every major stage shown.
Clarify that nighttime pumping returns water to the high-level reservoir rather than toward the river.
Coherence and Cohesion
The description progresses logically from storage through generation to the nighttime return cycle, with clear linking between stages.
Divide the long daytime sequence into shorter, more balanced sentences so each stage is easier to follow.
Lexical Resource
A suitable range of process vocabulary describes the reservoirs, intake, turbines, generator, and grid with generally good precision.
Replace vague expressions such as daylight stages and initial reservoir with the exact labels and directions shown.
Grammatical Range and Accuracy
Complex structures are handled accurately throughout, and the response contains a strong variety of clauses with very few errors.
Refine sentence boundaries in the longest process description to make the otherwise controlled syntax more concise.
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IELTS Academic Writing Task 1
The diagram below shows how electricity is generated in a hydroelectric power station.
Your response
Write the task yourself, then compare your choices with the annotated response.