The emission factors used by Greenly come from various sources (e.g. UK conversion factors, EPA, ADEME, Ecoinvent).
Often, an emission factor for the same product or process differs depending on the source. The order of magnitude of the EFs are often the same, but these differences can result in significant changes in the GHG inventory of a company. Methodological differences are usually the source of these differences.
For emissions resulting from electricity consumption, the emission factors that are used are provided by the French Environment Agency (ADEME), Electricity Maps, and the IEA (International Energy Agency).
Differences between ADEME and Electricity Maps
The main methodological difference between ADEME and Electricity Maps is the emission factor that is used for the production of electricity from gas.
💡EF of electricity production from gas
ADEME: 418 gCO2e/kWh
Electricity Maps 2021: 501 gCO2e/kWh for Electricity Maps
Electricity maps 2022: 612 gCO2e/kWh for Electricity Maps
Data source
It is difficult to identify the origin of the difference, as the source of the data is not the same.
ADEME uses ACV 2022, a comprehensive and recent study which was carried out, among other things, to assess the impact of the war in Ukraine (with Russian supplies replaced by gas from the United States and Qatar in particular)
Electricity Maps uses ENTSO-E and EU-ETS data
ℹ️ The Electricity Maps' value is closer to IPCC's median value (490 gCO2eq/kWh) while ADEME's value is closer to the lower bound (410 gCO2eq/kWh).
Methodology
There are also differences in the methodology that is used.
ADEME's French emission factors are computed with rolling averages using relatively precise data (e.g. the carbon intensity of natural gas, % of nuclear electricity in France, electricity production from wind turbines, etc).
Electricity Maps uses annual averages
French emission factor VS other countries
ADEME's emission factor for "France" is computed using a robust methodology with recent data.
However, the emission factors outside France provided by the ADEME are based on 2015 data from the International Energy Agency (IEA). Electricity Maps uses recent data for all countries.
Temporal granularity
Electricity Maps uses more granular temporal data compared to ADEME. Indeed, Electricity Maps uses country-specific values with an hourly time step: they take into account the time at which electricity is imported and the carbon intensity of the imported electricity at that hour.
🔌 E.g. Electricity imported from Germany in the middle of the day has a much lower carbon intensity than electricity imported during the night