GHG Protocol: Scope 1, 2 & 3 explained
A plain-English guide to greenhouse gas accounting — what each scope covers, why it matters for suppliers, and how to calculate your emissions.
The GHG Protocol is the world's most widely used greenhouse gas accounting standard. It provides a framework for measuring and reporting greenhouse gas emissions, and it underpins almost every major ESG reporting framework — CSRD, SB 253, TCFD, and more.
The three scopes
The GHG Protocol divides emissions into three categories — called "scopes" — based on where they occur in a company's value chain.
Scope 1 — Direct emissions
Scope 1 covers emissions from sources that are owned or controlled by your company. These are direct emissions — you produce them yourself.
Examples:
- • Burning natural gas in your boilers or furnaces
- • Fuel burned in company-owned vehicles
- • Emissions from industrial processes (e.g. cement production)
- • Refrigerant leaks from air conditioning systems
Scope 2 — Purchased energy emissions
Scope 2 covers emissions from the generation of purchased electricity, steam, heat, or cooling that your company consumes. You don't produce these emissions directly — they occur at the power plant or heat source — but you are responsible for them because you purchased the energy.
Examples:
- • Electricity purchased from the grid to power your factory or office
- • District heating or cooling purchased from a supplier
- • Steam purchased for industrial processes
Scope 3 — Value chain emissions
Scope 3 covers all other indirect emissions in a company's value chain — both upstream (from suppliers) and downstream (from customers and end-of-life). This is where most companies' emissions actually sit, and it's why your buyers are asking you for data.
Upstream examples (from suppliers — that's you):
- • Emissions from producing raw materials you supply
- • Emissions from transporting goods to your buyer
- • Emissions from your own operations (your Scope 1 & 2)
Downstream examples:
- • Emissions from using the products your buyer sells
- • Emissions from disposing of products at end of life
- • Business travel by employees
Why Scope 3 matters for suppliers
When your buyer reports their Scope 3 emissions, your Scope 1 and Scope 2 emissions become part of their Scope 3. This is why SB 253, CSRD, and TCFD all require Scope 3 reporting — and why your buyers need your data.
For most companies, Scope 3 represents 70-90% of their total emissions. This means that companies cannot achieve their net zero targets without reducing emissions in their supply chains — which means working with suppliers like you.
Common emission factors (DEFRA 2024)
Emission factors convert activity data (e.g. kWh of electricity, litres of fuel) into CO2 equivalent (CO2e). Here are some commonly used UK DEFRA factors:
| Activity | Unit | kgCO2e | Scope |
|---|---|---|---|
| UK grid electricity | kWh | 0.207 | Scope 2 |
| Natural gas | kWh | 0.183 | Scope 1 |
| Diesel (road) | litre | 2.51 | Scope 1 |
| Petrol (road) | litre | 2.16 | Scope 1 |
| Short-haul flight (economy) | passenger km | 0.151 | Scope 3 |
| Long-haul flight (economy) | passenger km | 0.195 | Scope 3 |
| HGV freight | tonne km | 0.0625 | Scope 3 |
| Rail freight | tonne km | 0.0280 | Scope 3 |
Ready to calculate your emissions?
ESG Stress Free's carbon tracking tool guides you through calculating your Scope 1, 2, and 3 emissions using the correct DEFRA or EPA emission factors.
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