I never thought I’d be writing about this, but a friend of my parents, who does work within the oil industry, was adamant that electric cars had a larger carbon footprint than diesel cars. To me, the thought of that is crazy. Electric cars are the future of road travel and soon everyone will be driving one, whilst diesel cars are on the way out with future plans to ban diesel cars in cities all over the world.


Even SUVs are going electric (Source: IOL)


But is there any truth to it? Straight away you consider the difference in emissions when the car is on the road. Diesel cars are immediately at a loss because electric vehicles don’t produce any emissions once they’re on the road. However, when it comes to building the vehicles there are many more rare earth metals required in the development of batteries that store the electrical energy used by cars. What impact does that have on the carbon footprint over the life of the vehicle?

So I thought I’d investigate. Whether he’s right or wrong, he’s not the only one being told that message. Looking at each stage of the life cycle of the car and identifying the emissions released in order to produce, drive and dispose of the vehicle will give an insight into just what kind of footprint both vehicles have and what is better for the environment, hopefully disproving the myth that diesel cars are better for the environment than electric cars.

Manufacturing the Cars

The natural place to start is with the manufacturing of the vehicles. For the most part, they’re the same. Cars vary in shape and size but much of the materials on your standard car are very similar. The big difference starts with what powers the car.

The biggest contributor to greenhouse gas emissions for electric cars is the development of the batteries used to power the vehicles. Whilst the batteries are very beneficial once they are in the car, they can have a number of environmental and social impacts during the mining and manufacturing phase.

Nickel, just one of the materials needed in batteries, is particularly toxic. In 2017, 17 nickel mines were closed in the Philippines due to environmental concerns. In 2016, a Russian nickel mining company shut down its plant over a huge spill into a nearby river, turning the water red, after contamination leaked from the plant. The smelting of nickel also produces huge clouds of sulphur dioxide that is toxic to humans and kill plants and animals.


A river bed affected by nickel poisoning (Source: The Guardian)


Diesel engines are predominantly made of iron and are constructed from parts made all over the world before being assembled in the car factory. The development of parts and the transport required for those parts to reach the assembly factory can rack up a pretty large carbon footprint but still cause less environmental damage to the planet than the development of batteries.

Where Does the Power Come From?

Diesel cars are obviously powered by diesel fuel, filled up whenever needed from petrol stations across countries. Some have a better mile per gallon (mpg) ratio than others or may have more efficient engines but the fuel is still the same and the harmful emissions like nitrogen oxides still have negative effects to human health. Unless car or engine manufacturers find a way to reuse or recycle the emissions that cause dangerous human health impacts, cleaner vehicles, like electric cars, will always have the upper hand.


Diesel emissions have serious impacts on human health! (Source: The Telegraph)


When considering the fuel source for Diesel vehicles we must also consider where that fuel comes from and the environmental catastrophes it has created. Huge oil spills like the Deepwater Horizon spill in the Gulf of Mexico and even smaller spills like the one in Borneo are all made possible because of our need for the fuel.

Here is where electric vehicles have a much bigger advantage. Electric vehicles can be plugged into mains power at home or any other electrical charging points that are popping up in cities all over the UK and the world. The majority of the UK is still powered on fossil fuels but the share of renewable energy is growing and is forcing coal out of the energy market. Right now, electric vehicles are most likely running off electricity generated by fossil fuels, but as we transition to renewable energy it won’t be long until the majority are running off renewables.

On top of that, electric cars don’t produce the same carbon emissions when on the road that their diesel counterparts do. It’s one of the great advantages of electric vehicles and why they are so often seen as the future of car transport. Having said that, they’re not free of harmful particulates…

Air Quality

This is of course linked to vehicle emissions but it comes back to another point raised; that a large amount of the particulates produced by diesel vehicles originate from the tyres as rubber is worn away on the road.

A study by Hooftman et al. (2016) found that electric vehicles pose the best solution for more environmentally friendly vehicles on our city streets whilst the petrol and diesel vehicles that are being marketed as more environmentally friendly aren’t much better than older, more pollutant vehicles. They did also conclude that non-exhaust (tyres, etc.) should be investigated and addressed in order to help reduce air pollution and make city streets even healthier.

Research by Timmers and Achten (2016) looked at doing just this. They found that in terms of the PM10 and PM2.5 emissions (particulates that can lead to respiratory disease and lung cancer), there was very little difference due to the additional weight of electric vehicles. Batteries are getting increasingly lighter and so will the cars they power but whilst we are still using rubber tyres, PM10 and PM2.5 emissions will always remain an issue, regardless of the fuel.


Electric vehicle batteries are still a huge contributor to the weight of the vehicle (Source: afdc.energy.gov)


Over Their Lifetime

So the production of diesel cars seems to be better because of the environmental damage caused by the mining and processing of metals for batteries in electric cars but when it comes to the road then electric vehicles are much better.

An article in The Guardian cites a report developed by researchers at VUB University in Belgium. They found that electric cars emit an average of 50% less greenhouse gas than Diesel vehicles over their lifetime. Across Europe, the results vary with the source of the energy for electric cars playing an important factor. In Poland, where coal is used widely to produce electricity, electric vehicles only produce 25% fewer emissions compared to Diesel. However, in Sweden where renewables contribute to a much larger share of the total electricity produced, emissions reductions can be as high as 85%.

So What Car is Best?

Both electric and diesel cars have their downsides. During the manufacturing phase, diesel holds the advantage due to the environmental and social impacts of mining the elements required for batteries. However, the emissions caused by diesel vehicles when they’re on the road is a big reason as to why cities and countries are beginning to ban the cars and view electric vehicles as the future of road transport.

I guess the conclusion to this is that if you have to buy a car, then electric is the way to go. Having said that, electric cars won’t be the solution to all of our problems. Instead, we must look towards using public transport and active forms of transport like walking and cycling much more to reduce the impact we are having on this planet. They’re the only truly clean forms of transport!

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