To BEV or not to BEV?
Electric vehicles (EVs) are often promoted as clean technologies and offer promising reductions in transportation emissions. EVs—which include battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs)—have surged in global popularity in recent years, showing no signs of slowing down. However, as the EV market expands worldwide, we must ask a tricky question: Are BEVs truly the environmental heroes they are made out to be? Or, to borrow from Hamlet— “to BEV or not to BEV”—do BEVs really “rid us of a foul and pestilent congregation of vapours,” or is the reality far more complicated?
Beyond the Hype
The idea for this research was born out of a mix of curiosity and concern. With the growing narrative around EVs as one of the solutions to mitigate climate change, we felt it was crucial to dig deeper. Climate change is undoubtedly one of the most pressing challenges of our time, making the reduction of greenhouse gas emissions critical. However, when evaluating the environmental impact of vehicles, the story extends beyond carbon emissions alone. To truly understand the broader picture, we must also consider other environmental impacts, such as acidification, eutrophication, and particulate matter. Only by accounting for these factors can we form a well-rounded judgment on whether BEVs are the optimal choice—or if other dominant vehicles, namely internal combustion engine vehicles (ICEVs) and hybrid electric vehicles (HEVs), might also play a crucial role in this critical conversation.
But what does it really mean to choose a sustainable vehicle? Is it simply about selecting a car with zero tailpipe emissions? Or are there more complex factors that we should consider?
Uncovering Complex Realities and Overcoming Challenges
In this study, we conducted a comprehensive life cycle assessment, comparing the lifecycle environmental impacts of four dominant light-duty vehicle categories: ICEVs, HEVs, PHEVs, and BEVs. This research posed significant challenges, from selecting case studies with broad relevance to analyzing a wide range of environmental impacts and modeling the dynamic nature of electricity grids.
One of the most rewarding moments came after much deliberation, when we identified two key environmental impacts to focus on: global warming potential and respiratory impacts. This decision felt like a breakthrough, as it allowed us to narrow our focus and delve deeper into two critical areas—one with global relevance and the other with localized effects. To better understand respiratory impacts, we separated them into tailpipe and non-tailpipe emissions, providing a nuanced analysis of their local environmental and health implications.
To ensure a comprehensive analysis, we combined a broad global perspective with detailed studies of three key countries leading the global EV market—Norway, the US, and China. These countries were selected not only for their significant roles in the EV industry but also for their distinct geographical locations, transportation profiles, and electricity grid mixes, making them ideal case studies with insights that can be applied to other countries worldwide.
However, the process was not without its setbacks. The dynamic nature of electricity grids proved to be a tough challenge. In our study, it was difficult to account for annual changes in the grid mix of each country, so we initially had to rely on a static grid mix, overlooking its dynamic evolution. Thanks to a valuable suggestion from one of our reviewers, we adopted the assumption that the grid mix changes linearly over time. Considering that vehicles typically have a service life of around 12 years, we used the 2030 grid mix scenario as a representative ‘mid-point.’ This mid-point falls between the vehicle’s manufacturing and the start of its service life in 2024 and its end-of-life around 2036, allowing us to estimate the environmental impacts of electricity usage over the entire service life cycle of EVs. This challenge strengthened our problem-solving abilities and ultimately led to a more robust and credible analysis. We want to highlight that the feedback from the review process not only provided a practical solution but also underscored the collaborative nature of scientific research.
A Mixed Bag of Insights
Our study reveals that consumers face a complex decision when choosing environmentally friendly light-duty vehicles. Factors such as expected vehicle lifespan, daily commuting distance, driving and charging habits, the electricity grid mix, and the availability of charging stations all play a role. We also provide valuable insights for policymakers, including recommendations on expanding charging infrastructure, incentivizing the retirement of high-emission vehicles, extending vehicle lifespans, promoting a cleaner energy grid, and carefully assessing emissions from fossil fuel-based power plants.
EVs are often seen as preferable because they produce no tailpipe emissions, which significantly improves air quality in urban areas. In contrast, ICEVs produce tailpipe emissions that degrade air quality, particularly during rush hour. However, focusing only on tailpipe emissions doesn’t capture the full lifecycle emission picture. Most respiratory effects associated with ICEVs come from the gasoline supply chain, including oil extraction, refining, and transportation. These emissions occur at various locations and times, differing from the cumulative nature of the global warming potential.
Most respiratory effects for EVs arise from electricity generation, meaning that shifting from ICEVs to EVs may relocate emissions—often still within lower-income or rural communities—and could even increase total emissions compared to ICEVs. While EVs have the potential to reduce carbon emissions as the electricity grid becomes cleaner, they may fail to address the increased respiratory impacts on vulnerable communities. This relocation of emissions could exacerbate environmental injustices, disproportionately affecting these communities.
Our Vision
We hope this study provides valuable insights for stakeholders in identifying environmentally friendly vehicle and policy options while considering multiple factors. Our journey is far from over, as it continues to highlight the complex realities of vehicle emissions and their broader impact on our world. Promoting sustainable transportation requires a holistic perspective that integrates environmental, transportation, energy systems, and environmental justice considerations.
To BEV or not to BEV? A Comparative Life Cycle Assessment of Battery Electric Vehicles (BEV) and Other Light-Duty Vehicles
