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Calculation methodology

How is the CO2 impact of my trip calculated?
Greentripper relies on the Bilan Carbone © approach of ADEME, which stands for Agence de l’Environnement et de la Maîtrise de L’Energie, i.e. the Environment and Energy Management Agency in France. This semi-public organisation is recognized worldwide for their greenhouse gas emission calculation tool/method known by the name of Bilan Carbone ©. The ADEME is one of the pioneers for the calculation of greenhouse gases and the conversion into CO2 equivalent in accordance with the Global Warming Potential (GWP), i.e. the contribution to the greenhouse effect.

Emissions from air travel depend on several factors:
  • The distance travelled and the size of the plane
  • The number of stopovers
  • Travel class
  • The number of travellers
How much does it cost?
The farther you travel, the more CO2 you emit. The cost depends on your destination and the transport used.

Simulate the carbon footprint of your trip on our calculator to see for yourself the degree to which climate protection is accessible. Compare the budget of your trip with the amount of the CO2 offset, it is generally less than 5%.

A few examples of air travel:
  • Brussels-Barcelona (Round trip – Economy class): €7 incl. VAT/per person for 560 kg of CO2 equivalent
  • Brussels-Lima (Round trip – Economy class): €56 incl. VAT/per person for 4,6 tonnes of CO2 equivalent
  • Brussels-Kigali (Round trip – Economy class): €34 incl. VAT/per person for 2.8 tonnes of CO2 equivalent
Why are the emissions indicated on the air ticket not the same as those calculated on Greentripper.org?
If we want to calculate the complete impact of air travel, we have to take into account the CO2 equivalent emissions but also other factors such as the radiative forcing (or high altitude) effect.
How much CO2 does an aeroplane emit?
According to the Institut Bilan Carbone, an aeroplane emits ca. 0.18 to 0.23 kg of CO2 per km per passenger in economy class.
If we take radiative forcing into account, the emissions are multiplied by approximately 2.
EU ETS System: What is the difference with the price of one tonne of CO2 on the market?
The price of CO2 on the market is the price for the European CO2 quotas.
The European quotas impose quota limitations on each large manufacturer who is a large CO2 emitter in the European Union. This entails that some companies are required to acquire additional CO2 quotas if they were to exceed the limit imposed at the European level.

On Greentripper, we propose voluntary offsetting. Voluntary offsetting is intended for the general public: private individuals, organisations, companies, etc. which are not required but nonetheless wish to reduce their impact voluntarily. Here, the price per tonne of CO2 avoided will depend on the project supported (development cost, location, technology, certification fee, etc.). The projects we propose on www.greentripper.org can avoid a tonne of CO2 for an amount between €12 and €20, incl. VAT, depending on the project, and are certified by the highest level labels such as the Gold Standard or Plan Vivo.
Why is there a difference between the price of Greentripper and the price of other calculators?
The differences are explained by the calculation methodology used.

At Greentripper we rely on the official Bilan Carbon © methodology of ADEME, whereby every emission factor is provided with an uncertainty of 20% to 50%.

With regard to air travel, on www.greentripper.org we invite you to offset the total impact: the CO2 equivalent emissions from the combustion of kerosene and the impact of radiative forcing.