An emission factor is a value that shows how much greenhouse gas, in CO₂ equivalent, is released per unit of activity: per cubic meter of gas, per kilowatt-hour of electricity, per ton of product. Emissions are calculated by multiplying activity data by the emission factor. The values come from IPCC methodologies, national sources or data from a specific energy supplier, and your choice directly affects the accuracy of the inventory.
The basic formula
Emissions = activity data × emission factor.
A worked example:
| Resource | Monthly consumption | Emission factor | Emissions |
|---|---|---|---|
| Natural gas | 8,000 m³ | 2.04 kg CO₂e/m³ | 16.32 t CO₂e |
| Grid electricity | 25,000 kWh | 0.726 kg CO₂e/kWh | 18.15 t CO₂e |
| Purchased heat | 30,000 kWh | 0.2 kg CO₂e/kWh | 6.00 t CO₂e |
The monthly total is 40.47 t CO₂e. The units of the emission factor must match the units of the data: if the gas invoice is in thousands of cubic meters and the factor is per m³, convert the units first.
Where emission factors come from
IPCC methodologies. The 2006 IPCC Guidelines, together with the 2019 Refinement, provide default values for fuels and processes. They distinguish three tiers of methods:
- Tier 1: IPCC default values that apply to all countries;
- Tier 2: national or regional factors that reflect a country's fuel composition and technologies;
- Tier 3: facility-specific data, such as measurements, fuel analysis and equipment models.
The higher the tier, the more accurate the result and the greater the data requirements.
National sources. These include national greenhouse gas inventories and official grid emission factors. In Belarus, methods and factors are set by the environmental norms and rules EcoNiP 17.09.08-001-2024 (see greenhouse gas accounting in Belarus); for Uzbekistan, the applicable sources are listed in the regulatory map once they have been reviewed.
Supplier data. An electricity retailer or a CHP plant may disclose the emission factor of its own generation. Such data is used, in particular, in the market-based method for Scope 2; see Scope 2: calculation methods.
How to choose an emission factor
- Match to the source. The factor must relate to the same type of fuel, the same technology and the same country or grid.
- Timeliness. Use values for the same or the nearest year; an outdated grid factor can noticeably distort Scope 2.
- Transparent origin. The source, year and version must be stated so that a verifier can check them.
- Consistency. Changing the factor from one year to the next requires recalculating the base year; otherwise, you will see a “reduction” caused by the methodology.
- Conservativeness. When in doubt, choose a value that does not understate emissions.
Estimated and confirmed values
Some factors in reference databases are marked as estimated: they were derived by calculation or from generalized sources and are suitable for an initial assessment. For reporting to a bank, a customer or a verifier, it is better to replace them with confirmed national or supplier values once such data becomes available. For how this affects the reliability of the result, see Data quality.
How it works in the platform
The platform takes emission factors and calculation methodologies from its own reference catalog, which brings together values from IPCC 2006, DESNZ and other sources. In simple input on the Data entry screen, you only need to enter the fuel and the quantity: the platform selects the methodology itself based on the unit of measure and the source category. In the expert variant, you choose the methodology explicitly. Every record shows the methodology applied, so you can always check which value was used in the calculation.
Frequently asked questions
Why does the grid electricity factor differ from one source to another?
It depends on the generation mix of the grid, the year, whether grid losses are included and the calculation methodology. That is why you should state the source and year, not just the number.
Can we use IPCC default factors?
Yes, especially when you are just starting out. This is Tier 1. For significant sources, it is worth moving to national or your own data over time.
Do past years need to be recalculated when a factor changes?
If the change significantly alters the result, yes: recalculate the base year and the comparable years so that the comparison remains valid.