What pollutes more: an electric car, a hybrid, a petrol car or a diesel?

Considering total CO2 emissions over the vehicle’s entire life cycle, electric cars are the greenest, followed by hybrids and diesels, with petrol cars bringing up the rear.

When it comes to polluting emissions, a distinction can be drawn between those that affect global warming and those that directly harm people’s health. The carbon dioxide, CO2, is responsible for the former. Among the latter we find nitrogen oxides, carbon monoxide and unburned hydrocarbons (particulates).

On 1 January 2020, a European regulation came into force limiting the average CO2 emissions of new passenger cars registered by each manufacturer during this year to 95 g/km, with heavy financial fines for those who exceed this figure. To reduce the CO2 emissions of their vehicle ranges, manufacturers must bet on electrification… or sell more cars with diesel engines.

The European Environment Agency estimates that, with European renewable energy policies that will allow electric cars to be charged with clean energy, the average emissions of this type of vehicle over its life cycle could fall from the current 60 g/km to 16 g/km by 2050.

Yes, you read that correctly. When it comes to carbon dioxide emissions, the main contributor to global warming, a modern car with a diesel engine emits less CO2 than one with a petrol engine, thanks to elements such as particulate filters or the use of AdBlue. For other types of emissions it is the opposite, as you can see in this article comparing which pollutes more, a diesel or a petrol car.

Curbing global warming: everyone against CO2 emissions

Pollutant emission regulations came into force in 1992 with Euro 1. Since then, car manufacturers have managed to reduce emissions of gases such as NOx by practically 95%, and they will continue to fall.

But CO2 remains a major problem. Between 1995 and 2021, the average reduction achieved reached 36%, and the measures imposed by the EU will bring a further 37% reduction by 2030.

The problem manufacturers face in avoiding fines of many thousands of euros if they exceed the 95 g/km average already set for this year is that electric cars, which lower the average the most, still have a very small market share. Hybrids are gaining ground, and diesel will inevitably regain the prominence it has unfairly lost.

Given this picture, reducing CO2 emissions has become the real goal. And the question quickly arises, since the regulation only takes into account emissions related to fuel consumption, that is, during use. But what happens if we compare the different propulsion systems considering the car not only when we use it, but also the emissions generated during its manufacturing process?

Electric cars emit the least CO2; petrol cars the most

A recent report from ARVAL, based on data from the European Environment Agency, sheds a little more light on something we might have taken for granted.

In an electric car, 51% of the emissions it generates over its entire useful life come from manufacturing. This is because manufacturing the battery requires a great deal of energy, and 40% of the total emissions associated with manufacturing the vehicle are generated in this process. The remaining 49% of all CO2 emissions of an electric car over its useful life can be attributed to generating the energy needed to produce the electricity it consumes, since it generates no emissions while in use. The potential for improvement here is significant to the extent that energy from renewable sources is used.

Manufacturing a car with a combustion engine emits between 1.3 and 2 times less than an electric one. However, unlike the latter, direct emissions are generated during its use due to the combustion process of the fuel. As much as 80% of all CO2 emissions over the useful life of a combustion-engined car come from exhaust gases emitted while driving. And in this case diesel beats petrol, since it emits between 20% and 25% less CO2, due to its greater energy efficiency and lower consumption. Let us remember that CO2 emissions are linked to consumption: the higher the consumption, the more emissions.

If we factor in CO2 emissions during manufacturing and in generating the energy needed to charge the batteries, the advantage of electric cars over combustion-engined ones drops considerably.

And just as with electricity in electric cars, emissions generated to produce the fuel must also be added. This figure is estimated at 19%, including the emissions from extracting, refining and transporting oil and its derived fuels.

And what about hybrid cars? During their manufacturing they emit more CO2 than a combustion car because they include batteries, though not as many as an electric car, since their batteries are much smaller. And in use, their emissions are around 35% lower than those of combustion-engined cars, thanks to electrification and their lower consumption.

As a final summary, an electric car emits between 17% and 21% less CO2 than a diesel, and between 26% and 30% less than a petrol car, considering the vehicle’s entire life cycle… not counting the CO2 emitted during recycling, which is another story!