IELTS Writing Task 1: Process Diagram with Sample Answer

Task 1 Question

The diagram shows how electricity is generated by a hydroelectric dam.

Write a 150-word report for a university lecturer explaining how the process works.

Model Answer

The diagram illustrates the basic principles of hydroelectric power. The process requires the construction of a large dam connected to a powerhouse. The dam creates a large reservoir and the powerhouse is where the electricity is generated.

First of all, water trapped in the reservoir behind the dam is forced through an intake. It then flows into a narrow chamber called a penstock, where the resulting high pressure turns a turbine. The turbine is connected to a generator in the powerhouse above, and this is where the movement of the turbine is converted into electricity. The resulting electricity leaves the powerhouse via cables that carry it over long distances to where it can be used.

It is interesting to note that a hydroelectric dam creates no harmful byproducts and relies entirely on natural forces to produce electricity. After the turbine stage, water flows out through a second channel and into a river. The process is renewable, thanks to the water cycle in nature.

(163 words, IELTS 8.0)

Why does this Task 1 answer get an IELTS Band 8 score?

Task achievement: The introduction paraphrases the question and describes the constituent parts of the process. The body describes each stage of the process in sequence.

Coherence and cohesion: The model answer has an introduction, body and conclusion. Sequencing expressions such as first of all, then and after are used appropriately. The articles a and the are used effectively to introduce and refer back to different elements of the process.

Lexical resource: The labels in the diagram are well integrated into the model answer and appropriate verbs such as converted, flows and leaves are used throughout. Less-common words such as byproducts and renewable are introduced by the writer. Spelling is always accurate.

Grammatical range and accuracy: The writer uses the present simple tense and has good control of subject-verb agreement and active/passive forms. A good balance of simple and complex sentences is used throughout.


20 thoughts on “IELTS Writing Task 1: Process Diagram with Sample Answer”

  1. A very good answer and deserves an 8 – but doesn’t the answer imply pre-knowledge of the process! Where are the arrows showing water flow direction? How do I know that the turbine is connected to the generator? The diagram doesn’t give enough information for a student who has never heard of a hydroelectric dam!

    1. Thanks for your comment, Ahmet. As you may already have guessed, the diagram wasn’t created for IELTS. I hope that, even without a label, it is clear to most people that the turbine is connected to the generator. Also, for someone who has never heard of a hydroelectric dam, the function can be deduced from the wording of the question.

    2. If you are taking IELTS Academic exam, you definitely must know what a hydroelectric is. It is basic, and nearly every student heard about it, at least once in life. So please, be prepared to have a minimum of knowledge of things.
      If you would know what gravity is, you would understand about the water flow direction!! C’mon!

  2. And yet another criticism…… in the diagram, where does it mention harmful products? renewable energy? İELTS answers like this should only reflect the information in the diagram.

    1. Thanks for your comment, Andrew. Accurate use of a word such as “renewable” that is not mentioned in the diagram displays lexical resource, which is one of the skills that can secure a band 8 score.

      In a concluding paragraph especially, a general sentence describing the overall process as simple, complex, clean or efficient is valid if based on what is shown by the diagram.

      Sometimes the creation of such a sentence can be a teachable skill in itself where the diagram may not give test-takers enough information to write 150 words.

    1. Hi, Mi. The band 8 score is just for guidance only. Most people will be aiming for band 7 at most in writing. Try to reproduce the style and organisation of the model answer above and you should have no problem reaching band 7 even with the occasional lexical or grammatical error.

  3. I cant think concluding section is good because write his own idea which is subtle in diagram. can we put our imagination in task one?

  4. Thank you very much for this essay, it helps me quiet well in my study; therefore, I wish to read more and more from this kind of essays.

  5. I have written a paragraph on this diagram, Kindly please comment on this.

    The process diagram depicts the basic principle of Electricity Generation in the Hydroelectric Power Plant. As can be seen from the diagram, there is a large size of dam connected to power house involved for such type power generation. The dam creates a large reservoir and the power is generated in Powerhouse.
    First of all water is trapped into the reservoir and forced by an intake. Then it is allowed to flow through a narrow chamber called Penstock. The turbine starts rotating due to the high pressure resulted from the flow of water. Once it starts to rotate, some mechanical energy is produced by the movement of the turbine and the generator which is connected to the turbine converts the mechanical energy into electrical energy. Finally the produced electricity are distributed by the long distance overhead transmission line. In the end the water flows out to the river through a second channel.
    It should also be noted that entire process is a recycling process that relies only on the natural forces of water and causes no harmful byproduct. Therefore the Hydroelectric Power generation is the greatest example of utilization of renewable energy.

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