Academic Writing Task 1 · process diagram

A diagram illustrating a potential future method for home energy production: IELTS Writing Task 1 sample answer

An IELTS Writing Task 1 process diagram question with a Band 8 sample answer, the chart redrawn with its data, the vocabulary that lifts the report and how to write about process diagrams.
  • 176 words
  • Process diagrams
  • Academic
  • 20 minutes

The question

The diagram below shows a possible future means of home energy production.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant. Write at least 150 words.

Home energy production process
  1. 1.Compost fermentation in a steel tank
  2. 2.Methane gas storage
  3. 3.Compression of gas
  4. 4.Combustion engine usage
  5. 5.Generator power production
  6. 6.Battery storage and home electricity supply

Chart redrawn by BandLadder from the data in the original IELTS practice task. Many IELTS practice tasks come from the Cambridge IELTS series (Cambridge University Press & Assessment); all rights in the original tasks remain with their owners.

Model answer

Band 8 sample answer

Band 8176 words. Every figure in the answer comes from the chart above.

The provided diagram illustrates a potential future method for generating electricity at home using organic waste. The process is a sequential system that transforms compost into usable electrical energy through several distinct stages.

In the initial phase, a steel tank is filled with a mixture of water and compost, such as food scraps and leaves. This material undergoes fermentation to produce methane gas, which is then directed into a storage unit. Following this, the methane is passed through a compressor, resulting in compressed gas that is transported to a combustion engine. This engine generates mechanical energy, which is subsequently fed into a generator to produce electrical energy.

Finally, the generated electricity is either directed for immediate home use or stored in a battery for later consumption. The entire system creates a closed-loop cycle, allowing households to become self-sufficient by converting everyday waste into a reliable power source. Overall, the diagram highlights a sustainable approach to energy production, demonstrating how organic materials can be effectively repurposed to meet domestic electricity requirements without relying on external utility providers.

Write your own report and get a band

Take a timed Academic writing test and get a band for task achievement, coherence, vocabulary and grammar, with the sentences to fix.

Write a report, get a band free →

Process diagrams

How to write about process diagrams: tips and vocabulary

  • →Say how many stages there are and where the process starts and ends.
  • →Use the passive and sequencers: first, after this, once, finally.
  • →Keep every stage; a missing step costs task achievement.
  • sequential

    following a logical order or a set sequence

  • subsequently

    happening after something else in a process

  • repurposed

    adapted for a different use or purpose

  • self-sufficient

    needing no outside help in satisfying needs

  • distinct

    clearly different or separate from each other

  • illustrates

    explains or makes something clear using images

Frequently asked questions

What should the overview say?+

The process describes a multi-stage system that converts organic waste into electricity through methane fermentation, mechanical combustion, and electrical generation.

How many words and how long for IELTS Writing Task 1?+

At least 150 words; 170 to 200 is the safe range. Spend about 20 minutes on it and leave 40 for Task 2, which carries twice the marks.

How is IELTS Writing Task 1 scored?+

On four criteria: task achievement, coherence and cohesion, vocabulary, and grammatical range and accuracy. A clear overview of the main features is what most separates Band 6 from Band 7 and above.

How do I describe process diagrams?+

Say how many stages there are and where the process starts and ends. Use the passive and sequencers: first, after this, once, finally. Keep every stage; a missing step costs task achievement.

Keep practising

More process diagrams

© 2026 BandLadder. Written and checked by the BandLadder team. You may quote or cite this page with credit to BandLadder and a link to it; republishing it in full needs our written permission. Content use policy

Write a report, get a band free