17 Mar 19

When is an EV greener than an ICE vehicle?

When is an EV greener than its ICE-powered counterpart? The answer is often used in the debate against or in favour of switching from ICE to EV. However, there's no simple answer. 

Last week a professor of the university of Liège, Belgium, claimed that the carbon footprint of an EV would only be smaller than the one of an ICE vehicle after 700,000km. However, the number was contested, so he adjusted his research and ended up at less than 35,000km or less than one tenth of his first result.

What’s in a number

Yet, even this number can be contested. As various studies have shown, with varying results, it's a mission impossible to put this in a single number. And here is why. 

The main difference between the 700,000km and 35,000km was the absence of certain factors which contribute to the carbon footprint of ICEs, and of EVs, such as the carbon footprint of the battery production, and the costs of the extraction, processing and transportation of fuel, which are all included in the second calculation.

Yet, the new calculation still does not include all carbon contributing factors of both cars. Completely absent is the carbon footprint of the production of the car as such, and the used materials, even though these are fundamentally different for ICEs vs EVs. 

Where to start?

Hence, first of all, the number depends heavily on the included factors, which are more plentiful and varied than one might think at first sight. For instance, the calculation can start with the production of the vehicle itself, including production of the materials, the production of the battery, including mining of the raw materials, the extraction of the fuel, and the type of energy used in all these processes, and the transportation of all goods, fuels and materials in the entire chain. All these factors contribute to the car’s carbon footprint while it is not even on the road yet.

On the road

Once on the road we can consider elements such as the fuel used in case of an ICE, or the energy source of the EV charging points. These factors depend on which type of ICE / EV we are comparing, and the driving style and driving circumstances. Further on, in case of the EV the lifetime of the battery must be taken into account as well, and the wear and possible replacement of the various compounds of the ICE, which tend to deteriorate faster than the ones of an EV. And shall we include tyres, their production, usage, wear and tear as well?

Where to end?

The carbon footprint of a car does not stop at the end of its life. Indeed, a big part of its carbon footprint is produced after its end of lifetime. Crucial in this regard is the process of recycling, and/or reuse of the vehicle, and in the case of an EV recycling and reusing the battery. If the battery can be reused as an energy storage unit it has a markedly smaller carbon footprint than when it has to be pulled apart and recycled. And in case of the latter, which energy is used for the recycling process, which technique is used, what is the amount of recycled materials, ...

Co-benefits or damage

The list of contributing factors to the real carbon footprint of an EV versus an ICE is limitless, and it is tough - not to say impossible - to come up with one single number for such a complex equation. 

All the more if you start taking other impacts than carbon footprint into account, meaning the co-benefits and/or damage from both types. 

For instance, while ICEs produce their polluting and damaging emissions for human and environment locally, even at breathing height via their tailpipe, the emissions of EVs are produced where the electricity is produced, mostly outside a city centre. 

Moreover, the energy consumed by EVs can be produced with renewable energy, reducing the carbon footprint, while the energy consumed by ICEs is per definition a fossil fuel (even biofuels are blended with fossil fuels). 
Hence, at least the local air quality benefits a lot of EVs compared to ICEs. In the same range, EVs produce less noise and less heath than ICEs do, improving the quality of their surroundings significantly compared to the ICE. 

Raw side

On the other hand, the extraction of the raw materials used for the EV batteries can be a controversial argument causing backlash against EVs. The mining of cobalt and the extraction of lithium have a huge impact on the ecological, social and economic situation of the places where they are extracted, the first mainly in the Democratic Republic of Congo, the latter mainly in the lithium triangle in South-America and in Australia. 

However, various players inside and outside the automotive sector are becoming aware of the problems and creating initiatives to guarantee the sustainability of the battery supply chain. Although the ICEs are not entirely free of this kind of discussions either, since they use raw materials as well, and the fuel they drive on has been the cause of many geopolitical conflicts as well and might continue doing that in the future.  

So, the number?

In a nutshell, expressing the carbon footprint of an EV versus an ICE might not only be a complex task, it might even be meaningless, taking all the beforementioned factors into account. 

Therefore, this article cannot conclude with a number but most studies addressing this question do conclude that in the end EVs have a lower carbon footprint than ICEs. 

It is difficult to tell when exactly the EV becomes more sustainable than the ICE-powered vehicle, one of the studies with the most authority within this regard, being the French study of ADEME (The French Agency for Environment and Energy Matrix), considers the carbon footprint of the EV lower than the ICE when compared over its entire lifetime.

Authored by: Fien Van den steen