How can you calculate the CO2 emissions from your company's electricity and gas consumption?

Electricity
A company wanting to calculate the CO2 emissions resulting from its electricity consumption must take into account the fuel mix, which differs depending on the type of chosen contract.
 

100% Green energy contract

• The used production means don’t generate CO2 emissions and there will therefore be no CO2 emissions resulting from the electricity consumption of the company having opted for this type of contract.
 

‘Grey’ energy contract

• To determine the CO2 emissions resulting from its electricity consumption, the company must multiply its electricity consumption (from nuclear energy and fossil fuels)  by a CO2 emission factor.

• ENGIE recommends using the official emission factor of the "Residual Mix" (excluding renewable production), which is calculated annually by AIB (Association of Issuing Bodies) based on the overall electricity production in Belgium. 
 

Source : VREG - www.vreg.be/nl/energieverbruik
The 2024 rate will be available at the end of May, beginning of June 2025. 

Only the percentage of electricity actually coming from nuclear energy and fossil fuels must therefore be taken into consideration in the calculation: 

• Renewable energy sources do not emit CO2.  

• Nuclear energy does not emit CO2. AIB already takes this into account when calculating the Residual Mix for Belgium. 

• The origin of the electricity made available to the company is available on each invoice. 
 

Illustration

A company consumed 100 000 KWh in 2023

- The emission rate calculated by AIB for Belgium for 2023: 167.49 g/kWh 
 

- The Fuel Mix of its electricity contract consists of: 
• 50 % fossil fuels 
• 40 % nuclear 
• 10 % renewable 
 

- CO2 emissions resulting from electricity consumption 
• 90 000 KWh (of (50%+40%) of 100 000 KWh) * 167.49 g CO2e/kWh = 15 074 100 g CO2e 
 

In Flanders, each customer can also check the origin of their electricity on the regulator's website (VREG), based on their EAN number;

Natural gas
A company that wants to calculate the CO2 emissions from its gas consumption must multiply its gas consumption by a CO2 emission factor. ENGIE recommends using following emission factor: 
 

This value is calculated by ENGIE using a “location based” approach. It is based on public data (grid flows) and own assumptions (emission factors per supply chain).