Electric car versus hydrogen car: which pollutes the most?

With nearly 10% of new market sales in France in 2021, the electric car is gradually becoming more democratic. Opposite, the hydrogen car is anecdotal, with a few dozen copies. Yet it could pollute even less. Let's see in detail how to calculate their CO ₂ emissions.

Battery and electricity under the magnifying glass

Running on electricity, the electric car emits no gas locally. It is thus necessary to look at the source of electricity to define its pollution during use. Depending on the country where you live, the electricity is more or less green. In France, we benefit from one of the greenest electricity in the world, around 30 gCO ₂ /kWh against more than 500 in Poland at the extreme in Europe. On the European average, count about 3 tonnes of CO2 for 200,000 km.

For the life cycle of the electric car, various studies have measured pollution during production. Unsurprisingly, the battery counts for a lot in its count. For a Renault Twingo E-Tech battery-powered city car, production inflicts 11.7 tonnes of CO ₂ according to the Swiss site TCS, compared to 25 tonnes for a Tesla Model S Grande Autonomie.

Hydrogen must be green

The hydrogen car is basically an electric car. However, instead of carrying a heavy battery on board, it generates its own electricity via a fuel cell. In this, it limits the environmental impact because the battery of barely 1 kWh is 50 times smaller.

However, you have to look at where the hydrogen comes from. Today, 95% of it is produced using fossil fuels (natural gas in this case). Nuance, the charging stations intended for the automobile tries to use electrolysis. This technology only uses electricity, preferably green, and water, without producing any polluting gas.

The same source comes to estimate the CO ₂ of a Toyota Mirai, sedan of size and autonomy equivalent to the Tesla. Its manufacture is as polluting as the Model S (16 tons), but less for its battery/battery duo (6 vs 10 tons). The Japanese sedan emits half as much energy (1.4 vs. 2.8 tonnes) and its disposal impact is negligible (0 vs. 1 tonne). Precision, it is necessary to divide by 3 the figure on energy if one uses French electricity.

Conclusion: less polluting hydrogen

As a result, the hydrogen car would emit 31 tonnes of CO ₂ over its lifetime, compared to 36.5 tonnes for the electric car. Please note that we only take into account the impact of CO2.

To be complete, it would be necessary to study the emissions of other gases during the manufacture or production of electricity, as well as the impact on water (not insignificant for the mining essential to the materials of the battery).