Electric vehicles are often hailed as a primary solution for combatting air pollution and climate change. This is because electric vehicles produce zero emissions at the point of use, such that replacing combustion engine vehicles with electric vehicles in cities and urban areas can have an immediate positive impact on air quality for large swathes of the population. As a result, local and national governments around the world are encouraging consumers to switch to electric vehicles, often by means of incentives such as subsidies or reduced road tax for electric vehicles. And these incentives seem to be working, with adoption of electric vehicles growing at a steady rate. For example, in the UK, vehicle registrations for pure electric vehicles in the first nine months of 2020 are up 127% compared to 2019.
However, a number of critics are questioning whether electric vehicles are truly a greener alternative to combustion-engine vehicles, particularly when the full life-cycle of the vehicle is taken into account. So, are electric vehicles actually as environmentally friendly as they might first appear?
The full life-cycle of a vehicle takes into account energy consumption over the entire life of the vehicle, i.e. including energy consumed for manufacturing the vehicle, as well as during its life on the road (with the average vehicle having a lifetime of about 150,000 km on the road). Computing the full life-cycle energy consumption for an electric vehicle can be quite tricky, as there are many factors to take into account.
Manufacture
The first thing to consider in a life-cycle analysis is the energy that goes in to manufacturing an electric vehicle. Electric vehicles are typically much more costly in terms of energy to produce than their combustion engine counterparts, mainly due to the energy intensive battery production. As a result, an electric vehicle will start out its life with a larger carbon footprint than a combustion engine counterpart, which it will need to make up for over its lifetime.
Of course, emissions associated with battery production will depend on how the electricity used in battery production is generated, which may vary significantly from country to country and even within a single country. Producing batteries using renewable energy, as will be the case for Tesla’s Gigafactory which makes the Tesla Model 3’s batteries, can therefore substantially reduce the life-cycle emissions of an electric vehicle. So, it is important to take into account where and how an electric vehicle’s battery is manufactured, in order to accurately estimate its life-cycle emissions.
Materials
The materials that go into an electric vehicle, and the manner in which they are obtained, also need to be taken into account. Indeed, electric vehicles involve a variety of exotic materials that need to be mined from the earth, from the lithium and cobalt which are used in their batteries, to the rare earths used for the magnets in their motors. The mining processes for extracting these materials are often energy intensive, as well as damaging to the environment. Cobalt, which is produced mainly in the Democratic Republic of Congo, is one of the more controversial materials involved, with reports emerging that its mining is not only highly polluting but involves child labour. In fact, a lawsuit was recently filed against Tesla and other tech companies by an international human rights group, alleging that these companies are profiting from cobalt mined by young children.
In an effort to reduce their reliance on cobalt, Tesla recently announced during their Battery Day event that they have developed a battery which does not use any cobalt, although they have not yet provided any technical details. Availability of the raw materials used in electric vehicles will be one of the major challenges moving forward, if electric vehicles are to achieve widespread adoption. So, it will be interesting to see if this development helps address this issue.
Life on the road
Carbon emissions produced from running a combustion engine vehicle will generally be the same regardless of where the vehicle is used, and will not change over the vehicle’s lifetime. In contrast, the carbon emissions produced from running an electric vehicle depend on how the electricity that is used to charge it is generated. So for a country like France (which gets most of its electricity from nuclear energy) or Norway (which uses mainly renewable sources), a large fleet of electric vehicles can significantly reduce carbon emissions.
Moreover, emissions produced from running an electric vehicle are likely to decrease over its lifetime, as countries transition away from fossil fuels and towards renewable energy. For example, the carbon intensity of the UK’s electricity was about 20% lower in 2019 compared to the previous year, leading to a corresponding drop in emissions for electric vehicles used in the UK. As a result, where a transition towards renewable energy is combined with a growing fleet of electric vehicles, there can be a significant reduction of carbon emissions.
Accordingly, when doing a full life-cycle analysis for an electric vehicle, it is important to take into account not only where the vehicle is used, but also predictions for how energy production will evolve over the vehicle’s lifetime.
Recycling and Second Life
When an electric vehicle reaches the end of its life, its battery will need to be recycled, or otherwise repurposed. However, recycling electric vehicle batteries can be a difficult and expensive process, particularly in view of the large variety in battery chemistries and designs used in electric vehicles. A recent study from the University of Birmingham reveals that the UK is drastically under-prepared to deal with the increasing numbers of electric vehicles that are reaching their end of life, and warns of ‘electric vehicle battery waste mountains’ if the proper infrastructure is not put in place.
According to the study, the UK would need eight gigafactories that specialise in recycling electric vehicle batteries by 2040. Such large scale battery recycling could represent a huge opportunity for the UK, by providing sources for the materials required for manufacturing electric vehicle batteries.
Due to the cost associated with recycling electric vehicle batteries, automakers are increasingly looking at ways in which used batteries can be repurposed to give them a second life before they need to be recycled. This is made possible by the fact that used electric vehicle batteries typically retain 70-80% of their original capacity. So, although they may no longer be fit for use in electric vehicles, they can still be used in less demanding applications. One example of this is Renault, which has partnered with maritime company Seine Alliance, to provide them with used electric vehicle batteries to power their ‘Black Swan’ boats.
Conclusion and outlook
Comparisons between conventional vehicles and electric vehicles are complex, due to the many factors at play. Nevertheless, studies have shown that, in most cases, where the above factors are properly taken into consideration, electric vehicles result in lower carbon emissions over their entire life-cycle compared to their combustion engine counterparts. Although the benefits of electric vehicles may currently be marginal in some countries which still use carbon intensive electricity generation methods, electric vehicles stand to make an increasing impact on carbon emission reductions as countries transition away from fossil fuels and towards renewable energy.
That said, important concerns around the materials used in electric vehicles, and the end-of-life disposal of electric vehicles, will need to be addressed if electric vehicles are to be seen as a truly green alternative to conventional vehicles.
