Ellen Phiddian
Cosmos science journalist
Electric vehicles (EVs) are going down in price, and up in size.
But as EVs get bigger, so does the amount of resource needed to make them. An electric SUV is a less “sustainable” vehicle than a smaller car, because of its gargantuan battery.
An opinion paper, published in PLOS Sustainability and Transformation, has called this trade-off into question, suggesting that “super-sized” electric vehicles won’t solve the climate crisis.
“To better align car purchasing with the goal of reducing greenhouse gas emissions, we need to educate consumers that replacing a conventional vehicle with an EV may not necessarily be reducing their emissions,” author Perry Gottesfeld, executive director of non-profit Occupational Knowledge International, tells Cosmos.
While studies have often found that EVs are lower emitting than internal combustion engine (ICE) vehicles over their lifetime, even in many places with fossil-fuel dominated grids, their lithium batteries are energy-intensive to mine and make.
“Bigger vehicles require more raw materials, more energy that goes into the manufacturing and assembly, into their use – that’s not to mention the other issues related to safety,” says Scott Dwyer, a sustainability researcher at University of Technology Sydney, who was not involved with the paper.
“But this is a problem for all types of vehicles – internal combustion engine [vehicles] as well.”
Larger batteries require more energy, making larger EVs less sustainable than their smaller electric counterparts.
In the article, Gottesfeld points out that the top 10 highest selling EVs in the USA in 2023 had a mean battery weight of 595kg, a 68% increase on the 5 most common models in 2019.
“Although the data in our article focused on the US, it is important to note that this trend is not limited to the US as more than half of the EV models available in China, Germany, France and the UK in recent years were SUVs or large cars,” says Gottesfeld.
“Consumers aren’t just attracted to those vehicles because that’s their preference,” says Dwyer. “There’s a lot of market push from the automakers to sell these larger, more expensive vehicles as well.”
Gottesfeld argues that policymakers should find ways to incentivise smaller cars.
“As in the past when climate focused consumers selected vehicles based on fuel economy, we need to facilitate the selection of EVs based on lifetime greenhouse gas emissions.”
These incentives could include things like taxes based on weight.
“It does raise an important issue around the weight of the vehicles that consumers are choosing,” says Dwyer of the paper.
“But it does miss much of the detail, which is actually a really important part of the conversation around how we’re transitioning from fossil fuel-based transport to one that’s based on batteries and electricity.”
Dwyer says that electricity grids around the world are decarbonising, meaning that EVs are increasingly being run on lower-carbon energy – especially when there’s a lot of rooftop solar.
“EVs are the perfect solar sponge to soak up excess renewables in the middle of the day, which is something that internal combustion engine vehicles can’t do,” says Dwyer.
“The operational emissions of any electric vehicle will be less than other fuel sources, especially considering their running efficiency, and this will only get better as we decarbonise our electricity grid,” says Kai Li Lim, an EV researcher at the University of Queensland, who also wasn’t involved with the paper.
Lim adds that mining, manufacturing, and recycling of EV materials is expected to become more efficient over time.
“We’re still in very early generations for EVs,” says Dwyer. “Lithium-ion batteries are still a much less mature technology compared with internal combustion engines.”
Both researchers point out that a large car or a small car are not our only options.
“I am personally a proponent of mode shift where I believe the best way to minimise our carbon footprint is to shift to active or shared (public) transportation modes,” says Lim.
“I think there are policy levers which can be pulled to encourage more positive, sustainable modes of transport,” says Dwyer.
These levers could be things like improved vehicle standards, extending product life, and encouraging public and active transport.
