As a science-based method, LCA is an excellent tool to bust the myths that surround sustainability. In this monthly series, we look at some common sustainability ideas to see if they are myth or true. In today’s episode we discuss electric vehicles. Are they really the best option?
Electric vehicles (EVs) are here to stay. The worldwide sales of EVs grew by 60% in 2015 and it is expected that by 2035, 35% of the passenger cars sold will be electric. But which kinds of cars have the lowest environmental impact? EVs, hybrid vehicles (HVs) or internal combustion vehicles (ICVs)? The arguments are not totally clear.
Looking At The Life Cycle Of Cars From An LCA Perspective
In this new chapter of Sustainability Mythbusters, I will try to give some answers to the questions around green mobility and electric vehicles for passenger use, and thus help clarify if EVs are a more environmentally friendly option. To do this, I will present some facts and practices from life cycle assessment (LCA) that will help us to compare the different types of vehicles. LCA is a powerful tool that explicitly quantifies the use of resources and emissions along the entire life cycle of a product or process: it provides a more objective way to compare and take decisions.
If you want to use LCA to select the most environmentally friendly mobility option among the cars we discussed, it is important to take the big picture into account. A complete LCA study for passenger vehicles should cover the raw materials extraction, the manufacturing process, the operation phase (including driving cycles, fuel consumption and mileage, parts replacement, etc.), and the end-of-life stage.
Not That Many Differences In Building The Vehicles
When it comes to the raw materials extraction and manufacturing process, the basic components for the three types of cars are pretty similar. The main difference is in the battery: for EVs, a lithium-ion battery is the most common type, while for HVs nickel-metal hydride or lithium-ion batteries are both common.
The main issue with battery manufacture is the use of rare earth elements, solvents and high amounts of energy. For this reason, this stage in EVs or HVs exceeds the global warming emissions compared to those of conventional vehicles. In this sense, the ICVs have more mature and established channels for manufacturing and material recycling: the technologies involved have been around for several years.
The Use Phase Is Very Different, Though
Several studies on this topic have shown that the operation stage is the most dominating factor in the environmental footprint of cars. Combustion vehicles have the greatest energy use and emissions in the operation stage of all car types under discussion, because they require substantial amounts of energy for fossil fuel processing and consume large quantities of fuel throughout its lifetime. The choice of fuel (petrol, diesel or biofuel) and the efficiency of the engine are also important factors, increasing or reducing the impact in this stage.
HVs score a little better. Hybrids have approximately half of the emissions of ICVs, due to the fuel economy achieved by a higher battery capacity, the combination of a conventional engine and electric motor, the automatic start and shut down and the energy recovery during braking.
The best score goes to the EVs, which have the lowest impact. However, even though EVs have no tailpipe emissions, it is misguided to claim that they have zero impact. The reality is that the emissions and impacts occur during generation and distribution of electricity. Therefore, the electricity mix used for powering the EVs will determine the degree of the impacts: an electric car charged in a coal-intensive electricity system would have similar emissions as a fossil fuel vehicle. Using renewable energy should be preferred.
And What About End Of Life?
The end-of-life stage also affects the impacts of a vehicle. In all cases, an important factor is how feasible it is to recycle materials, how well this is done, and how recycling affects the quality of the materials. Although it is possible to recycle lithium, it is not worth it from a financial point of view: mining it is cheaper. While nickel-metal hydride batteries have a lower weight and are better alternatives to lead batteries, they have a high rate of self-discharge and thus are discarded or replaced more often.
One way to reduce the impacts at end of life for batteries is to re-use them in other systems or smaller vehicles that do not require as much storage. This is a valid idea, as EV or HV batteries still have 70% to 80% of their original capacity at their end of life.
Electric Vehicles Are The Best Option For Green Mobility: Myth Or Not?
Electric vehicles are a key component in the transition towards more sustainable mobility. If your electricity source has a high share of renewables and is clean and efficient, it is environmentally smart to drive an EV. Moreover, the impact of its operation phase can be reduced even more if you also use other forms of transport, such as the train, public transport, or bike.
Still, there is a long road ahead before EVs become fully environmentally friendly options. Technology will improve, as there will be developments in battery manufacture to use fewer materials and, hopefully, rare earth metals. Better recycling processes will also be an important solution to the end-of-life unknowns we are facing today.
Uncover More Sustainability Myths
This is the twelveth part of our Sustainability Mythbusters series. See other episodes:
Sustainability Mythbusters XI: Biofuels and Food Shortages
It’s easy to use ‘common sense’ and make assumptions in sustainability, but does that get you the results you want? If you want to learn how you can use sustainability metrics to uncover more myths for your company, drop me an e-mail or contact my team.