Step 5: Collect activity data
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This is step 5 of 7 in Build your GHG inventory. Previous: Step 4: Identify your emission sources. Next: Step 6: Calculate your emissions.
Activity data is the measured amount of each activity that causes emissions, such as litres of diesel or kWh of electricity. In this step you collect it for every source on your list, for the whole reporting period. Good activity data matters more than anything else for an accurate inventory.
What data each source needs
| Source | Activity data | Usual unit | Where to find it |
|---|---|---|---|
| Boilers and generators | Fuel used | litres, m³, kg | Fuel invoices, delivery notes, tank readings |
| Company vehicles | Fuel used, or distance | litres, km | Fuel cards, fleet logs |
| Refrigerant leaks | Refrigerant added during servicing | kg, by type | Maintenance records, service invoices |
| Purchased electricity | Electricity used | kWh | Electricity bills, meter readings |
| Chilled water or steam | Energy used | kWh, GJ, RT-h | Supplier invoices |
| Purchased goods | Quantity or spend | tonnes, RM | Procurement system, invoices |
| Freight | Weight and distance | tonne-km | Logistics records, freight invoices |
| Waste | Weight by type and treatment | tonnes | Waste contractor reports |
| Business travel | Distance by mode and class | passenger-km | Travel agency reports, expense claims |
| Employee commuting | Distance, mode and days | km | Staff survey |
Fuel quantity is better than fuel cost, because fuel prices change. For refrigerants, the amount added during servicing is a common way to estimate how much leaked.
Primary and secondary data
- Primary data comes from your own operations or from your value chain partners: meter readings, invoices, supplier emissions figures.
- Secondary data comes from averages: industry data, databases, or spend-based estimates.
Use primary data for Scope 1 and Scope 2. For Scope 3, primary data is best for your largest categories. Secondary data is acceptable for smaller ones and to fill gaps. IFRS S2 asks you to explain how much of your Scope 3 uses data from specific activities in your value chain.
Judge the quality of your data
The Scope 3 Technical Guidance uses 5 tests of data quality. They also work for Scope 1 and Scope 2:
| Test | Question |
|---|---|
| Technology | Does the data match the technology that you actually use? |
| Time | Does it come from the reporting period? |
| Geography | Does it match the place where the activity happens? |
| Completeness | Does it cover all sites and the whole period? |
| Reliability | Is it measured or verified, or only estimated? |
Methods for purchased goods and services
For Scope 3 category 1, the Technical Guidance describes 4 methods, from the most to the least specific:
- Supplier-specific: product emissions data from your suppliers
- Hybrid: some supplier data, with averages for the rest
- Average-data: the weight or quantity of goods multiplied by an average factor
- Spend-based: the money spent multiplied by an average factor per RM or USD
Many companies start with the spend-based method and move to better methods for their largest suppliers.
Plan the collection
Turn your source list from step 4 into a plan. For each source, record who provides the data, in what format, how often, and by when. Monthly collection helps you find errors early. Annual collection is easier but leaves less time to fix problems.
When data is missing
- Find the gap. Note which site, source and months are missing, and why.
- Judge its size. Estimate how much it could change the total.
- Fill it. Use data from other months, a similar site, or an average, for example kWh per square metre of office space.
- Record it. Write down the method, so that a reviewer can follow it. Replace the estimate with real data when you can.
Keep the evidence
Keep each invoice, meter reading and survey result, and note where the number came from. An assurance provider will ask for it. Good practice in carbon accounting explains what an audit trail needs.
Check your progress
Before you go to step 6, make sure that you have:
- Activity data for every source, for the whole reporting period
- A note of the data source and quality for each figure
- A record of each gap and how you filled it
In Carbon GPT
Record each item of activity data as a measure in Measures, with its date, facility, amount and unit. To collect data from colleagues or suppliers, send a form with Requests. Their answers come back as measures after you approve them.
Sources
- GHG Protocol Corporate Standard, chapters 6 and 7
- GHG Protocol Corporate Value Chain (Scope 3) Standard, chapter 7
- GHG Protocol Technical Guidance for Calculating Scope 3 Emissions, introduction and category 1
- IFRS S2 Climate-related Disclosures, paragraphs B38–B57
