Do electric cars pollute more than combustion cars?

Do electric cars pollute more than combustion cars?

A panacea according to some, an environmental disaster according to others - what about the pollution generated by an electric vehicle? Is an internal combustion car really more polluting than an electric car?

28/9/2022

Is it really more ecological to drive an electric car?

0 kgCO2 for an electric car, really?

Recent studies tend to show that, taking the most complete analysis of emissions, from manufacturing to end of life (LCA), the electric car is much less polluting than its internal combustion counterpart, at least in terms of greenhouse gases (Carbone 4, 2022; Sacchi et al, 2022; International Council on Clean Transportation, 2021...) .

This observation is true for any particular vehicle by comparing, with a similar model, a combustion car and a battery electric car. It is necessary to break down the different sources of emissions over the life cycle of the vehicles in order to understand the criticisms that are made of electric cars, and to conclude that electric cars emit less CO2 than combustion cars over their lifetime.

Lifetime greenhouse gas emissions for two vehicles, kgCO2e
Lifetime greenhouse gas emissions for two vehicles, kgC02e

The manufacture of an electric vehicle: a polluting process.

Electric vehicle emissions are largely due to the manufacturing of the vehicle, and in particular the manufacturing of the battery. As its many critics point out, the production of an electric vehicle is indeed more polluting than that of a thermal vehicle; and the more powerful the battery, the greater the emissions linked to its manufacture. By way of comparison, for two similar city cars, the manufacturing phase represents 40gCO2e/km for a gasoline-powered vehicle, compared to nearly twice that, 77 gCO2e/km for an electric vehicle (Carbone 4, 2020).

Manufacturing greenhouse gas emissions by engine, kgCO2e
Manufacturing greenhouse gas emissions by engine, kgCO2e

The electric car is more ecological in use.

While the electric vehicle loses out in the first phase of production, this is not the case in the other phases of the life cycle. What makes the electric vehicle particularly interesting from a climatic point of view is the phase ofuse of the vehicle: a gasoline or diesel car or one that runs on another fuel emits greenhouse gases as soon as the engine is running. These "tail pipe" emissions do not exist at all in the case of electric vehicles. In addition to these emissions, there are emissions from the extraction of the fuel and its transportation.

Does an electric vehicle emit greenhouse gases while driving?

Things are more complex. The consumption of electricity to drive the vehicle does not emit GHGs. On the other hand, the production of the electricity used to run an electric vehicle does emit greenhouse gases. However, in Europe, and particularly in France, where electricity production emits little CO2 on average, these emissions are very low, and make the use of an electric car a much less carbon-intensive means of transport than a petrol or diesel car.

In the United States, where electricity production is more carbon intensive because it is produced from coal combustion, the tipping point for the number of kilometers to be covered for an electric vehicle to be more "ecological" than a gasoline vehicle will be higher than in France.

Greenhouse gas emissions by engine and country of use, kgCO2e
Greenhouse gas emissions by engine and country of use, kgCO2e

End of life, similar emissions

Under the assumptions made by the most recent studies (Carbone 4, Carculator), end-of-life emissions are relatively similar and, above all, much lower than emissions from other stages of the life cycle.

The electric car less polluting: is it true everywhere and all the time?

In view of the significant emissions during the manufacturing phase of a car, which depend directly on the weight of the car and the power of its battery for electric cars, the comparison between a small gasoline Clio and a Tesla Model X becomes necessary.

Indeed, when comparing all the elements, is it better to take a small gasoline car that doesn't consume much, or a big electric SUV of 2.5 tons very powerful? Which one emits less CO2, over its lifetime?

It is difficult to compare the two in terms of the overall environmental impact of the manufacture and use of cars . As far as climate impact is concerned, in France, the evidence points in the direction of electric cars, particularly in the case of a low-carbon electricity mix.

By way of comparison, for one kWh of electricity consumed in France, 0.05 kCO2e will be emitted, whereas in India, where electricity production also depends largely on coal-fired power plants, one kWh consumed will have emitted more than 0.72 kgCO2 (IEA, 2022) .

A large electric SUV starts to be better for the climate than a light gasoline car E95 (segment B) after 78 115 km :

Greenhouse gas emissions in use for a light-duty gasoline vehicle and a heavy-duty electric vehicle, kgCO2e
Greenhouse gas emissions in use for a light-duty gasoline vehicle and a heavy-duty electric vehicle, kgCO2e

Does an electric car only become "profitable" ecologically after 10 years of use?

It all depends on the model. Compared to an internal combustion engine car, the electric car is only "profitable" from a climate point of view after a certain number of kilometers have been driven. As for knowing what distance must be covered for the electric vehicle to be more interesting than the combustion vehicle, our simulator allows us to answer the question: https://evfootprint.org/

The mileage of a vehicle at the end of its life averages over 170,000 km, so for all vehicles, the finding goes in favor of electric (Weymar & Finkbeiner, 2016). As Carbone 4 points out, the issue may arise in the case of secondary vehicles in a household, which drive significantly less than a primary vehicle (Carbone 4, 2022).

In fact, the number of real kilometers driven that allow to pass this milestone is surely lower, and the electric car is more interesting than in the model we propose. We have made the conservative assumption of an energy mix that does not vary over time, whereas current trajectories project a general decarbonization of the electricity mix, particularly in Europe (McKinsey, 2022)

For an average electric vehicle in Europe, compared to an average thermal vehicle, electric becomes on average more interesting from 42,827 km, i.e. a little less than 5 years (8920 km/year in 2019 on average in France - Statista, 2021)

Is the electric car so clean that we can choose any model with our eyes closed?

By comparing the different models of electric cars, it quickly appears that the largest SUVs (often decried by the detractors of the electric car) are indeed much more emitting than small models. Our comparator shows that a small electric car is much less emitting than a larger model:

Greenhouse gas emissions in use for two sizes of electric vehicle, kgCO2e
Greenhouse gas emissions in use for two sizes of electric vehicle, kgCO2e

A light electric vehicle will be "cleaner" from a climatic point of view than a light gasoline vehicle quite quickly, whereas it will take a significant number of kilometers driven to "make the use of a large electric SUV profitable" climatically.

An electric sedan (segment D) will start to have less impact on the climate than a gasoline-powered city car (segment B) after about 100,000 km. On the other hand, a large SUV will need almost twice as many kilometers to be less polluting than a light gasoline vehicle.

With a clean vehicle, there is no need to change our habits? 

The transition from conventional thermal vehicles to vehicles using other fuels is the path that legislators are now putting forward in order to reduce greenhouse gas emissions, both on a national and European scale. To this end, it is absolutely necessary to understand the real reduction of the environmental impact of our vehicles, with the different types of alternative motorizations: electric, but also hybrid, biofuel, hydrogen, etc.

However, it is imperative to question our use of the car in parallel, because the change of transport mode will not be a sufficient lever to achieve the reduction of impact to which the states have committed themselves in the framework of the Paris Agreements.

TheInternational Energy Agency (IEA) at the beginning of the year, and then the major energy suppliers a few weeks ago, reminded us that sobriety, i.e. the reduction of our consumption, travel and uses, was necessary to face the double constraint of the reduction of available fossil fuels and to limit climate change. One of the first levers of sobriety is to favour means of transport with a low impact on the climate, such as bicycles, public transport, trains, etc.

The media Bon Pote deciphers in an article with Guillaume Martin the advantages of mobility by bike, and defeats the preconceived ideas on this means of transport which is an efficient and low-carbon alternative for short trips: The bike is the future of our mobility.

Conclusion

Car use is one of the most important sources of emissions on a national and individual scale. The objectives set internationally by the Paris agreements require us to question our uses and the possible alternatives to traditional mobility. In line with the findings of Carbone 4, Transport & Environment and the Paul Scherrer Institute, an electric vehicle is less emissive than its thermal equivalent for a main vehicle, even in countries with a more carbon-intensive energy mix than France.

Except in the case of secondary vehicles (which drive an average of 3,000 kilometers per year), it is therefore useful for the purpose of reducing emissions to promote the use of electric cars rather than gasoline-powered cars. However, this transition raises other societal and geopolitical questions, which Carbone 4 attempts to answer in this comprehensive FAQ: Preconceived ideas about electric cars.

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