Welcome back to the IELTS Writing section on englishlanguagestudies.com! While many students prepare endlessly for line graphs and pie charts, they often panic when they turn the page and see a IELTS Writing Task 1 Process Diagram. A process diagram illustrates how something is made or how a system works.
To score a Band 7.0 or higher on a process diagram, you must demonstrate two specific skills to the examiner:
- The Passive Voice: You should not write, “A machine pumps the water.” You must write, “The water is pumped by a machine.”
- Sequencing Language: You must guide the reader smoothly from one step to the next using words like initially, subsequently, following this, and finally.
In this guide, we will break down the perfect structure for describing a process, give you a highly technical practice prompt, and reveal a flawless Band 9 sample answer. Let’s get writing!
IELTS Academic Writing Task 1
Learn how to write in the passive voice, analyze the process diagram below, and write your own 150-word response before checking the Band 9 sample.
1. The Practice Prompt
You should spend about 20 minutes on this task.
The diagram below shows how geothermal energy is used to produce electricity.
Summarise the information by selecting and reporting the main features, and make comparisons where relevant.
Write at least 150 words.
Or use the text data below to practice!
1. Cold water is pumped down a tube (Injection Well) 4.5 km into the ground.
2. Water passes through an Injection Zone into a Geothermal Zone (Hot Rocks).
3. The hot rocks heat the water.
4. Hot water is pumped back up to the surface through a second tube (Production Well).
5. At the surface, hot water enters a Condenser and turns into Steam.
6. The Steam spins a Turbine.
7. The spinning Turbine powers a Generator, which produces electricity.
8. Electricity is sent to the Power Grid.
2. The Perfect 4-Paragraph Process Structure
To score highly on a process diagram, follow this specific 4-paragraph layout:
Paragraph 1: The Introduction
Write one sentence that paraphrases the prompt. (e.g., The provided diagram illustrates the step-by-step process of generating electricity using geothermal energy.)
Paragraph 2: The Overview
For a process diagram, your overview should state exactly how many total stages there are, and what the first and final stages are. Do not explain the middle steps here.
Paragraph 3: Body Paragraph A (The First Half)
Group the steps logically. For this diagram, Paragraph A should cover the “Underground Phase” (pumping the cold water down, the hot rocks, and pumping the hot water back up). Remember to use the passive voice!
Paragraph 4: Body Paragraph B (The Second Half)
This paragraph should cover the “Surface Phase” (the condenser, the turbine, the generator, and the grid). Use strong sequencing words like subsequently, following this, and finally.
3. Check Your Work
Set a timer for 20 minutes and write your response. Once you are finished, open the accordion below to read a Band 9 sample answer and see how it utilizes sequencing and the passive voice.
🏆 Click Here to Reveal the Band 9 Sample Answer
Sample Response:
The provided diagram illustrates the step-by-step process of generating electricity by harnessing subterranean geothermal energy.
Overall, the process consists of five primary stages, beginning with the pumping of cold water deep underground and culminating in the distribution of electricity to the grid. It is a cyclical system that relies entirely on natural sub-surface heat and mechanical conversion.
Looking at the initial underground phase of the process, cold water is pumped from the surface down an injection well to a depth of approximately 4.5 kilometers. At this extreme depth, the water passes through an injection zone and enters a geothermal reservoir composed of naturally hot rocks. As the cold water travels through these heated rocks, its temperature rises significantly. Once heated, the pressurized hot water is forced back up to the surface through a separate pipe known as a production well.
Following this, the surface phase of the operation begins. Upon reaching ground level, the hot water enters a condenser where it is converted into high-pressure steam. This steam is then directed into a mechanical turbine, causing the blades to spin at high speeds. The kinetic energy generated by the spinning turbine is used to power an attached generator, which ultimately produces electricity. In the final step of the process, the generated electricity is transmitted away from the facility to the wider public via high-voltage power lines.
(231 words)
How did your response compare? Did you notice the strong use of the passive voice in the sample answer? Phrases like “cold water is pumped,” “is forced back up,” and “is converted” are exactly what the examiner is looking for to award a high band score for Grammatical Range and Accuracy.
When you practice process diagrams, always take a minute to count the steps and clearly define where the “first half” of the process ends and the “second half” begins so your paragraphs are perfectly balanced.
Let us know in the comments: Do you prefer describing Process Diagrams or numerical charts (like Bar Charts and Line Graphs)?
Check out more IELTS Academic Writing Task 1