Electrified vehicles: a solid choice

It is well known that the transportation sector contributes significantly to global environmental impacts, especially climate change. The electrification of our vehicle fleet has been posed as a cleaner alternative to the burning of fossil fuels.
But while electric cars produce no tailpipe emissions, other environmental issues — such as depletion of resources needed to produce these cleaner technologies — have cast doubt on the future of electric cars. Life cycle assessment (LCA) would have us look more broadly at the all environmental impacts of a vehicle, from resource extraction through to end-of-life disposal. In doing so it becomes apparent that the methods of life cycle assessment are flexible, the answers nuanced, and conflicting opinions often arise. In a recent study, researchers explored some of the broad conclusions that can be drawn from decades of work in LCA of passenger vehicles.
 
In the study, published in the International Journal of Life Cycle Assessment, LCA experts from universities in Sweden and Belgium reviewed the results of 79 studies aimed at assessing the environmental impacts of hybrid, plug-in hybrid, battery electric, and internal combustion passenger vehicles.In the study, they pay articular attention to goal and scope definition within each LCA study.The authors ask what has been learned from so-called "well-to-wheel" studies that concern themselves with the energy carrier in vehicle energy systems.The authors also explore the environmental impacts embodied in the vehicle equipment and materials as well as end-of-life scenarios.Finally, the authors synthesize conclusions regarding environmental impacts beyond climate change.
 
Broadly speaking, it was found that the more electrified the drivetrain the better its environmental performance. Within this general statement lie a number of important caveats. The first is that the true benefit of electrifying our vehicle fleet can only be realized if we transition to clean, renewable energy. This is perhaps obvious, but the point is rarely highlighted in many of the reviewed publications. Second, it has been shown that the batteries utilized in electric vehicles carry an environmental burden in addition to those found in a comparable gas-burning vehicle, but this does not overshadow the benefit of eliminating fossil fuel combustion. Overall, the reviewed studies show that the impacts associated with vehicle fuel systems cause more environmental damage than the materials used to construct the vehicles themselves. However, the environmental impact of material components will increase relative to fuel systems as renewable energy is utilized more widely. Finally, 100 percent of the reviewed studies noted the importance of recycling vehicle and battery components in order to reduce environmental impact. 
 
Although it is often forgotten, there are important environmental considerations beyond climate change. The emission of toxic substances during material production for electric and hybrid-electric vehicles has previously is often cited. This study supports earlier findings that battery-based electric vehicles do mobilize more toxic substances than comparable vehicles run by internal combustion. Many of the toxic materials are released during resource extraction, and these could be drastically reduced if best practices in the mining industry spread around the globe. Resource depletion is also a concern. A look at the impact assessment methods typically used forces the authors to conclude that the toolkit available for assessing resource depletion impacts is lacking at the present time. In particular, the rare earth metals of concern receive little coverage in all of the major impact assessment models. 
 
In the end, there is not so much confusion over results as we may sometimes hear. Different conclusions tend to result from differences in the processes considered and the time scale of the analysis. It is hoped that greater care in framing future studies can limit subsequent miscommunication of results. Finally, the future prospect for electrified vehicles appears heartening. The internal combustion engine is a mature technology, and offers much less room for improvement than do its comparatively young competitors. Looking to the future, a change in vehicle technology can be expected to reduce our environmental footprint.