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Calculation methodology

The ClimatePartner carbon calculator enables you to calculate carbon emissions in everyday life. The modules Flights, Passenger Cars and General Emissions are currently available.

Module ‘Flights’

The ‘Flights’ module calculates greenhouse gas emissions from national and international air travel. For calculating the emissions, the departure and destination airports, the booked transport class, the number of passengers and the route category (single/round-trip) are taken into account.

We take the emission factors for the calculation from a recognised scientific database and update them regularly. The calculation model includes direct emissions from combustion, indirect emissions for the provision of the infrastructure and manufacture of the means of transport (e.g. proportionate emissions from aircraft production) and surcharges for any detours and queues. The flight class also considers the space requirements of the passengers traveling (transport class) and includes these accordingly.

In addition to the direct emissions caused by the combustion of kerosene, we include also indirect effects of air travel on the climate. Indirect effects result from the emission of particles at high altitudes, which may contribute to additional cloud formation and global warming (so-called "radiative forcing" effect). There is agreement that this effect is significant, but the amount of the correction factor to be applied (RFI factor) cannot be clearly determined scientifically. ClimatePartner is therefore guided by current practice, which places the RFI factor between 2 and 5 depending on the calculation model. ClimatePartner calculates with an RFI factor of 3, which is applied to direct emissions from air travel.

Module ‘Cars’

The module ‘Cars’ calculates carbon emissions resulting from the use of cars. The calculation is carried out either by specifying the vehicle category (e.g. “middle class”) or by supplementing the data with the individual average consumption and fuel type.

The emission factors for the calculation are taken from recognised scientific databases. In addition to the direct emissions resulting from the combustion of fuel, indirect (upstream) emissions resulting from the production and distribution of fuels are also taken into account. Greenhouse gas emissions resulting from the manufacture of the vehicle are not considered.

Calculation of vehicles with internal combustion engines

The combustion of one litre of fuel always causes the same amount of carbon emissions – regardless of which vehicle or engine technology is used to burn it. This also applies to gas-powered vehicles that run on natural gas or LPG, for example. Therefore, for a precise carbon calculation, only the real consumption of the vehicles and the type of fuel are decisive. Other factors – such as the EU standard for vehicles or the year of construction – are also not decisive for the carbon calculation, since carbon emissions – unlike nitrogen oxides – cannot be reduced by filter systems or engine cleaning technology.    

Calculation of electric vehicles

Analogous to the calculation of vehicles with combustion engines, the calculation of carbon emissions from electric vehicles is based on real consumption (in kWh/100 km) and the type of electricity generation. If vehicles are operated with 100 percent green electricity, there are no direct carbon emissions for use. Only indirect carbon emissions that result from the manufacture of the power plants and the provision of the electricity are taken into account (so-called "upstream emissions"). Therefore, even an electric car powered by 100 percent green electricity produces a small amount of carbon emissions.

For vehicles that are not powered 100 percent by green electricity, the national electricity mix is used for the calculation. This is updated annually and is currently just under 500g CO₂/kWh in Germany. In addition, we consider the indirect carbon emissions from electricity generation ("upstream emissions").

Calculation of hybrid vehicles

When calculating hybrid vehicles, two cases must be distinct: 

1) Plug-in hybrid vehicles: Plug-in hybrid vehicles have an electric motor with external charging capability and a combustion engine. For the carbon calculation, the consumption of primary fuel (e.g. diesel) is taken into account and the electrical component is automatically considered on the basis of corresponding average values. For the calculation, therefore, only the consumption of the respective primary fuel has to be specified.

2) Other hybrid vehicles: Hybrid vehicles without their own charging facilities are considered based on their consumption of primary fuel.

Module ‘General’

The module enables the compensation of emissions that you already know or have calculated elsewhere.