Band 8.0 IELTS Writing Task 1 Model Answer

Overall Band Score: 8.0 · Cambridge IELTS 14 · 2026-09-29

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 8.0)

The diagram shows how a hydroelectric power station functions, demonstrating the process of electricity generation during the day and the method used to pump water back into the system at night.

In essence, the operation is a continuous cycle. Water flows from an elevated reservoir to produce electricity during daylight hours, while energy is used at night to pump the water back to the higher reservoir for future use. This method ensures a steady supply of electricity and helps conserve water for ongoing energy generation.

Throughout the day, water from the high-level reservoir, which is supplied by a river, flows through an open intake and drives turbines that can operate in reverse, which are connected to a generator. These turbines convert the kinetic energy of the water into electrical energy, which is then transmitted to the national grid. After the water passes through the turbines, it is collected in a lower reservoir.

At night, the intake is closed, and the station switches to pumping mode. In this phase, the turbines reverse their direction and use electricity from the grid to pump the water back from the low-level reservoir to the high-level reservoir, setting up the system for the next day's electricity generation cycle.

AI examiner evaluation

Task Achievement / Task Response: Band 8.0

The response fully satisfies the requirements of Academic Task 1 by providing a clear, accurate summary of the hydroelectric power station process. The student successfully identifies all the main features, including the dual-phase cycle operating during the day and night, the flow of water from the high-level to the low-level reservoir, the electricity generation phase, and the nighttime pumping mechanism. An effective overview is provided in the second paragraph, capturing the continuous cyclic nature of the system. The description of the mechanical and structural components, such as the reversible turbines and the open and closed intake valves, is grounded accurately in the source diagram without any misinterpretation of data.

Coherence and Cohesion: Band 7.5

The text demonstrates a logical sequence and progression from introduction to the overview, followed by the daytime phase and finally the nighttime phase. Paragraphing is used very effectively to group related aspects of the process. Cohesive devices are handled naturally, with appropriate transitional phrases such as 'In essence', 'Throughout the day', and 'At night'. Referencing is clear throughout, ensuring that the reader can easily track the movement of water and the shift in operations between daylight hours and the night cycle. There is no mechanical overuse or awkward structuring.

Lexical Resource: Band 7.5

The student uses a wide and precise range of vocabulary appropriate for describing a technical process. Terms such as 'elevated reservoir', 'daylight hours', 'kinetic energy', and 'pumping mode' demonstrate a high level of lexical control. There are also skillful attempts at less common lexical items and collocations, such as 'continuous cycle' and 'steady supply of electricity'. Word choice and spelling are accurate throughout, with no noticeable errors that would detract from the fluency of the response.

Grammatical Range and Accuracy: Band 8.0

The response features a wide and flexible range of complex grammatical structures used with a high degree of accuracy. The majority of sentences are error-free, and the writer handles subordinate clauses and participial phrases skillfully, as seen in 'turbines that can operate in reverse, which are connected to a generator' and 'setting up the system for the next day's electricity generation cycle'. Control over tense, punctuation, and subject-verb agreement is exceptionally strong, reflecting a high level of grammatical competence.

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