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Emission factor: definition and sources

An emission factor converts an activity datum (kWh, litre, kg, km, etc.) into a quantity of greenhouse gas. It is the building block of any carbon footprint calculation.

Definition and unit

An emission factor is expressed in kgCO₂e per unit of activity (e.g. about 0.079 kgCO₂e/kWh for French electricity). Multiplied by the quantity consumed, it gives the corresponding emissions.

Reference sources

The main databases are ADEME's Base Empreinte® (the reference in France), Agribalyse (food), DEFRA (United Kingdom), EPA (United States) and EXIOBASE (monetary approach). Choosing an official, up-to-date source is essential for credibility.

Generic or primary data

A generic factor (from a database) is convenient but average; primary data (measured at the supplier, e.g. via an ISO 14067 certificate) is far more accurate. UltraCarbon favours certified data when available.

Frequently asked questions

Where to find official emission factors?

In France, ADEME's Base Empreinte® is the public reference. UltraCarbon integrates it and automatically selects the right factor based on what you declare.

Does an emission factor change over time?

Yes, databases are updated (electricity mix, methodologies). A good tool records the version used and freezes it in the certificate.

Measure your footprint with UltraCarbon

Free estimation, ISO 14067-compliant certificates, data hosted in France.

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