Combustion engine, hybrid or electric cars: what are the differences in carbon footprint?

illustration: wind turbines and solar panels

When looking to reduce your carbon footprint related to mobility, you often ask yourself: is it better to keep a combustion engine car? Opt for a hybrid? Switch to electric? The answers are not as simple as they seem, because each technology has different impacts, whether during manufacture or use. Find out how these different types of engines compare and how Nos Gestes Climat calculates their impact.

The three main categories of engine explained

Internal combustion engine
Internal combustion engine cars include any vehicle whose engine runs exclusively on petrol or diesel. This type of vehicle emits CO₂ mainly during use, through fuel combustion, which is associated with a high carbon footprint per kilometre travelled.
Hybrid car
Depending on the model, hybrids combine a combustion engine with an electric motor. In a "traditional" hybrid, the electric motor assists the combustion engine; in a plug-in hybrid, the battery can be recharged from the mains and allows the vehicle to run on electric power alone for short distances. The stated benefit is lower fuel consumption and therefore lower emissions during use.
Electric car
Electric vehicles run exclusively on a battery that is recharged from the mains. They do not directly emit CO₂ during use, but their manufacture, particularly the production and extraction of materials for the battery, results in a high initial carbon footprint. Their advantage is therefore measured over their entire life cycle, depending on the distance travelled and the source of the electricity used.

Manufacturing, use, recycling: which emission sources should be compared?

Usage is not everything!
To get the full picture, we need to analyse not only **usage **but also the **manufacture **and **end of life **of the vehicle. These different elements are detailed in the Mobitool database.

  • Manufacturing:
    Vehicle production is an important factor, especially for electric models, due to the battery. This includes the extraction of materials, industrial processing, assembly and transport to the dealership.
  • Use:
    Here, the distinction is more familiar: a combustion engine car emits CO₂ for every kilometre travelled (proportional to consumption and fuel type), a hybrid emits less when used optimally, and an electric car can be very low carbon if the electricity is decarbonised... or higher if powered by coal.
  • Recycling/end of life:
    The end of life of the vehicle (dismantling, battery recycling, reuse of parts) is also taken into account in the calculation, even though it accounts for a small proportion compared to manufacturing and use (in terms of CO₂ emissions).

How is the carbon footprint of different vehicles calculated?

To ensure a fair and transparent assessment, Nos Gestes Climat uses the Mobitool database. This Swiss reference assigns a **footprint per kilometre travelled **that includes:

  • Emissions generated during **manufacturing **(including the battery and the size/dimensions of the vehicle).
  • Emissions during **use **(fuel or electricity consumption, technical efficiency).
  • A distinction based on vehicle type (city car, compact car, SUV, etc.).

Carbon comparison: some key figures

Of course, the exact figures depend on the model, driving style, number of kilometres travelled per year and the electricity mix .
However, the following figures can be used as a guide: