What we calculate
CarbonPass uses UK Government DEFRA 2024 conversion factors and follows the GHG Protocol Corporate Standard to calculate Scope 1, 2, and 3 greenhouse gas emissions.
| Source | Input | DEFRA factor | Available on |
|---|---|---|---|
| ✓Natural gas | kWh from utility bills | 0.18254 kgCO₂e/kWh | All plans |
| ✓Company vehicles — diesel | Litres consumed | 2.51262 kgCO₂e/L | All plans |
| ✓Company vehicles — petrol | Litres consumed | 2.16802 kgCO₂e/L | All plans |
| ✓Company vehicles — HVO | Litres consumed | 0.25400 kgCO₂e/L | All plans |
| ✓Refrigerants / F-Gas | kg leaked × GWP | IPCC AR6 GWP values | Business & Partner |
| ✓On-site generators | Litres fuel consumed | Same as vehicle fuels | Business & Partner |
| ✓Forklifts / LPG machinery | Litres LPG consumed | 1.555 kgCO₂e/L | Business & Partner |
| ✓Oil-fired heating / kerosene | Litres consumed | 2.540 kgCO₂e/L | Business & Partner |
| Source | Input | DEFRA factor | Available on |
|---|---|---|---|
| ✓Electricity | kWh from utility bills | 0.20705 kgCO₂e/kWh | All plans |
| Source | Input | DEFRA factor | Available on |
|---|---|---|---|
| ✓Business travel — flights | Passenger-km by class | DEFRA 2024 air travel factors | All plans |
| ✓Business travel — rail | km travelled | DEFRA 2024 rail factor | All plans |
| ✓Waste disposal | Tonnes by disposal method | Landfill 0.467, Recycled 0.021, Composted 0.010 kgCO₂e/kg | Business & Partner |
Coming soon
| Source | Scope | Expected |
|---|---|---|
| 🕑Employee commuting | Scope 3, Cat 7 | Q3 2026 |
| 🕑Purchased goods & services | Scope 3, Cat 1 | Q3 2026 |
| 🕑Capital goods | Scope 3, Cat 2 | Q4 2026 |
| 🕑Upstream transportation | Scope 3, Cat 4 | Q4 2026 |
| 🕑Waste water treatment | Scope 1 | Q3 2026 |
| 🕑District heating | Scope 2 | Q4 2026 |
| 🕑Waste-to-energy / incineration | Scope 3 | Q4 2026 |
Our approach
We use the UK Government’s DEFRA 2024 Greenhouse Gas Conversion Factors for all calculations. These are updated annually and represent the most authoritative UK emission factors available.
Our methodology follows the GHG Protocol Corporate Standard — the world’s most widely used greenhouse gas accounting framework. We apply the location-based method for Scope 2, with market-based (REGO) as an option.
Carbon Reduction Plans generated by CarbonPass meet the structure and content requirements of Procurement Policy Note 06/21, including baseline emissions, reduction targets, and Scope 3 category reporting.
Assumptions and estimations
- When utility bills are missing for some months, we estimate using the average of available months — clearly marked as “Estimated” in your report.
- F-Gas leak rates default to the industry standard 15% when exact leak data is unavailable.
- Fleet fuel from annual summaries is distributed evenly across 12 months.
- Waste tonnage can be estimated from bin counts using standard UK commercial bin weights.
- Generator fuel can be estimated from operating hours using manufacturer consumption rates.
- All assumptions are logged and visible in your Carbon Report for full auditability.
Scope 3 category reporting
PPN 006 requires organisations to report on relevant Scope 3 categories or justify their exclusion. CarbonPass currently covers Category 5 (Waste) and Category 6 (Business Travel). Other categories are excluded with standardised justification text in your CRP, noting they will be included in future reporting periods as data collection capabilities expand.
Frequently asked questions
DEFRA publishes updated conversion factors annually, typically in June. We update CarbonPass within 30 days of publication to ensure all calculations use the latest authoritative factors.
Yes. If you have REGO (Renewable Energy Guarantee of Origin) certificates from your electricity supplier, CarbonPass applies a zero emission factor for that electricity. Without a valid REGO certificate, we use the UK grid average (location-based method).
CarbonPass provides estimation tools for common scenarios — estimating annual usage from partial bills, generator fuel from operating hours, waste tonnage from bin counts, and refrigerant leaks from charge weight. All estimates are clearly marked in your report and CRP.
Yes. Carbon Reduction Plans generated by CarbonPass meet the structure and content requirements of Procurement Policy Note 06/21, including baseline emissions, reduction targets, Scope 3 category reporting with justified exclusions, and a formal board approval statement.
Questions about our methodology? Email us at hello@carbonpass.co