A German study on the environmental impact of vehicles places models running on natural gas (NGV) ahead of electric ones. But if this classification is valid across the Rhine, it is not necessarily so in France. Explanations.
In addition to an economic interest, cars running on natural gas (NGV) would have an ecological interest compared to other vehicles, including electric ones. This is the conclusion of a study conducted by ADAC, a German automobile association.
As a reminder, CNG, not to be confused with LPG, is a natural gas used by certain bi-fuel cars. In France, its market share remains anecdotal with only 172 new dual-fuel petrol/NGV vehicles registered in 2021, i.e. 0.01% of sales (source: C-Ways). By way of comparison, cars running on Superethanol-E85 and those running on dual-fuel gasoline/LPG represented respectively 0.15 and 2.80% of registrations over the same period.
The authors of the study analyzed the polluting and greenhouse gas emissions “from the well to the wheel” of 112 cars, driven by different energies. This balance therefore includes the production of energy and its transport, with in particular the losses on recharging for an electric vehicle, for example.
CNG is stored in gas form, unlike LPG stored in liquid state. © Volkswagen AG
If the car tested emitting the least CO2 is electric, namely the Hyundai Kona Electric SUV, with 84 g of CO2/km, the overall ranking, also taking into account polluting emissions (carbon monoxide, fine particles, oxides of nitrogen, etc.), is driven by two models running on CNG. In first position, we find the Seat Leon 1.5 TGI (overall score of 103, against 101 for the Kona Electric), followed by the Volkswagen Golf equipped with the same engine (overall score of 102).
It should be noted, however, that this study seems to forget fine particle emissions from the brakes, which are much lower on electric and hybrid cars thanks to their regenerative braking system. Taking this into account, the ranking could therefore change. Similarly, the authors started from the premise that a dual-fuel petrol/CNG car only runs on CNG. Unfortunately, with their autonomy of around 400 km on LPG and a limited distribution network, their drivers are sometimes forced to run on petrol, which emits more CO2 and pollutants. The production of an electric car, however, has a heavier environmental impact.
The hydrogen-powered Toyota Mirai scores an overall score of 93. The first petrol car tested is the Suzuki Swace Hybrid, which is a rebadged Toyota Corolla Touring Sport 1.8 L, with an overall score of 90, and the first diesel car is the Seat Leon equipped with the 2.0 TDI, with an overall score of 84. The Renault Captur E-Tech Plug-In 160 takes first place among plug-in hybrids, with an overall score of 72.
A ranking also valid in France?
If, according to the ADAC, cars running on CNG have a slight environmental advantage over electric cars, this study applies to the German market. Across the Rhine, 40% of compressed natural gas is organic (biogas), compared to only 19.6% in France in 2021, according to the AFGNV (French Association of Natural Gas Vehicles).
In addition, the carbon footprint of German electricity production is much heavier than in France. At home, one kilowatt hour of electricity produced in 2021 generated an emission of 53 g of CO2 equivalent on average, compared to 414 g in Germany (source: IPCC).
In summary, if the study had been carried out in France, electric cars would certainly have the advantage. The bi-fuel gasoline/NGV models are not without interest, but the offer remains quite limited. Only the Volkswagen group and Fiat offer them.