Electric Cars Are Not A Silver Bullet

A new study finds that even converting every car would still produce too much CO2.

Parked Teslas ready for delivery
Parked Teslas ready for delivery. ADRIAN DENNIS/AFP via Getty Images

A new study published in Nature Climate Change has a title that says it all: "Electrification of light-duty vehicle fleet alone will not meet mitigation targets." The first sentence of the abstract will sound familiar: "Climate change mitigation strategies are often technology-oriented, and electric vehicles (EVs) are a good example of something believed to be a silver bullet." But alas, it's not enough.

The study, led by Alexandre Milovanoff of the University of Toronto* Faculty of Engineering, started with the United States emissions budget for light-duty passenger vehicles (LDVs) to meet the 2050 target for keeping under 2°C. They did a full life-cycle analysis, calculating the total carbon footprint of the EVs, their batteries, and the electricity supply, to determine what would be required to come in under budget.

Treehugger is preoccupied with embodied carbon, the upfront carbon emissions from the manufacturing, and Milovanoff responded to our question about these:

"Yes, we included embodied carbon of the vehicles. We use a life cycle approach and accounted for emissions of battery, body, chassis, etc. Manufacturing, fuel production, fuel use, and vehicle end-of-life processes. To be specific, we quantify the amount of steel, cast iron, aluminum and calculated the resulting GHG emissions."

Milovanoff and his supervisors, Daniel Posen and Heather Maclean, conclude that 90% of the existing cars on the road in the U.S. would have to be replaced with EVs. That's 350 million new electric cars, and 100% of sales by 2050. "To put this into perspective, sales of EVs in the United States represented 0.36 million vehicles in 2018, or 2.5% of new vehicles, with an on-road fleet of 1.12 million EVs at the end of 2018 "

These would need a lot of electricity; 1,730 terawatt-hours, about 41% of all the electricity generated in the U.S. now. However, the paper acknowledges that there is an opportunity to use EVs as mobile storage to "flatten the shape of the demand curve" – soaking up excess power in off-peak times. But it means that you can't look at EVs on their own, they have to be thought of as part of a larger system:

"It is therefore crucial that EVs are integrated within a broader framework to ensure that their deployment reduces CO2 emissions without causing technical instability to power systems. This will come at the cost of deploying a large amount of renewable-based electricity, ‘smart’ infrastructure, and behaviors."

Then there are the 3.2 terawatt/hours of batteries that would be needed. "Without drastic changes to EV battery material composition or major improvements to the recycling processes of the used batteries, up to 5.0, 7.2 and 7.8 Mt respectively of lithium, cobalt and manganese would need to be extracted between 2019 and 2050 for the US LDV fleet alone." The authors acknowledge that battery improvements and new technologies can go a long way to dealing with this, but "it will take time to find and deploy effective and affordable alternative technologies – time that cannot be afforded in the face of climate change urgency."

How Big a Vehicle Do You Need?

Hummer specifications
We only have the specs so far. GM

The study addresses a concern that we have expressed on Treehugger: the way electric vehicles may be following the pattern of gas-powered vehicles and getting bigger, requiring more batteries, more electricity, and more embodied carbon, which is why we are getting Electric F-150s, Cybertrucks, and even Hummers. "Safety and other factors need to be considered in the weight control decision but a trade-off between performance, size, features and vehicle efficiency needs to be found." The authors add:

"Heavier electric vehicles indeed have higher electrical consumption that may not lead to greater range. Therefore, incentives to promote EV deployment should not prevent manufacturers from developing heavier vehicles, for range expansion, but should limit weight inflation."

Milovanoff clarified this for Treehugger, who wondered why manufacturers should be allowed to make heavier vehicles at all; why not keep them all small and light? He explained:

"If we limit BEV to only small cars, we will hinder their deployment to specific utilizations (smaller range so mostly urban driving). In addition, BEVs are way more efficient than conventional vehicles (80% compared to max 40%). So a heavy BEV is less “damaging” than a heavy conventional vehicle. I think that an electric F150 is an absurd idea, but a heavy Tesla with a very long range is not that absurd if that helps EV deployment. My message is about compromise and about weight (not sizes). We should be willing to drive smaller vehicles. But comparing the weight of a conventional vehicle with a BEV is not fair, we probably need heavy BEVs to get high range. Heavy, not large."

Electrification Is Not a Silver Bullet 

The authors conclude by noting that just going electric will not close the mitigation gap, and that "betting solely on EVs to remain within suitable sectoral CO2 emission budgets for the US LDV fleet would imply more than 350 million on-road EVs in 2050, adding half of national electricity demand and requiring an excessive amount of critical materials." Instead, they call for alternatives to the car as a way of reducing emissions even further that require less technology, including transit-oriented land-use policies, public transport, and "innovative taxes." They write,

"Electrification is not a silver bullet, and the arsenal should include a wide range of policies combined with a willingness to drive less with lighter, more efficient vehicles."

Or as Heather Maclean noted in the University of Toronto press release,

"EVs really do reduce emissions, but they don't get us out of having to do the things we already know we need to do. We need to rethink our behaviours, the design of our cities, and even aspects of our culture. Everybody has to take responsibility for this."

Perhaps Treehugger has been overly dramatic with titles like "Why We Don't Need Electric Cars, but Need to Get Rid of Cars" or "Electric Cars Won't Save Us: There Are Not Enough Resources to Build Them," But Milovanoff and Maclean put real numbers to the point that electric cars won't save us on their own; we need all of the above.

*The author is an alumnus of the University of Toronto.