Putting EVs to the test

What’s Your Number?

By Dan Kolbert

AS A BUILDING CONTRACTOR, big pickups have been part of my life for decades. Along with their size comes, of course, terrible gas mileage, with common EPA estimates in the low teens per gallon. My crew rarely works more than 10 miles from our shop, so we make up for the bad mileage by driving fairly few miles. One of our crew, though, drives a fair amount and doesn’t typically need many tools with him. So this past year, we picked up a surprisingly affordable used, fully electric Nissan LEAF.®

Learning how to plan trips around charging stations and times has been challenging at times, but otherwise it’s been a terrific experience. The mechanical simplicity makes me optimistic that it will need fewer repairs compared to an internal combustion engine (ICE) vehicle. And my inner teenager loves electric vehicles’ scorching acceleration, with no changes of gears.

But are EVs quantifiably better for the environment? If so, under what circumstances and for how long? I looked into the research, and this month’s numbers will be about the various ways people have quantified the question.

In 2022, Massachusetts Institute of Technology’s Climate Portal published a report called “Are electric vehicles definitely better for the climate than gas-powered cars?” As contributors Andrew Moseman and Sergey Paltsev point out, producing lithium-ion batteries is a major source of upfront carbon emissions during the EV manufacturing process: “Building the 80 kWh lithium-ion battery found in a Tesla Model 3 creates between 2.5 and 16 metric tons of CO2... This intensive battery manufacturing means that building a new EV can produce around 80% more emissions than building a comparable gas-powered car.”

However, as Climate Portal points out, the vast majority of a vehicle’s CO2 and equivalents are emitted by driving it, not building it. They quote a Department of Energy study that looked at average annual CO2 equivalent (CO2e) pollution across vehicle classes:

EVs, 3,932 lbs
Plug-in hybrids, 5,772 lbs
Standard hybrids, 6,258 lbs
Standard internal combustion engine vehicles, 11,435 lbs.

With a metric ton being about 2,200 pounds, the additional CO2e from the Tesla battery could be recouped in as little as a year. Every year after that would save 3.5 metric tons, compared to an ICE car. With the rapid development and adoption of battery recycling technology, both the carbon load of batteries and environmental and social impact of mining will be lessened even further.

Of course, how we charge an EV’s battery has a lot to do with its environmental impact. There’s a big difference between charging off of our home’s solar panels or from a coal-fired power plant. And if you live in Maine, we already enjoy one of the cleanest public energy supplies in the country.

Even so, Paltsev reports that “it’s difficult to find a comparison in which EVs fare worse than internal combustion. If electric vehicles had a shorter lifespan than gas cars, that would hurt their numbers because they would have fewer low-emissions miles on the road to make up for the carbon-intensive manufacture of their batteries. Yet when the MIT study calculated a comparison in which EVs lasted only 90,000 miles on the road rather than 180,000 miles, they remained 15% better than a hybrid and far better than a gas car.”

CHART RECREATED FROM IMAGE PUBLISHED IN THE MARCH, 2024 EDITION OF THE RENEWABLE AND SUSTAINABLE ENERGY REVIEWS ARTICLE TITLED “SUSTAINABILITY CHALLENGES THROUGHOUT THE ELECTRIC VEHICLE BATTERY VALUE CHAIN” https://doi.org/10.1016/j.rser.2023.114176

Still, the environmental impact goes beyond carbon accounting. An article published last year by Anahita Jannesar Niri and colleagues in Renewable and Sustainable Energy Reviews titled “Sustainability challenges throughout the electric vehicle battery value chain” looks at the “uncertainties in a sustainable supply of battery minerals, environmental, social and governance complexities, and geopolitical tensions throughout the whole battery value chain” and how they have “shaped the global and regional concerns over the success of transport decarbonization.”

It’s a dense paper, but suffice it to say that decarbonizing the transport sector—which involves regulatory agencies, governments, mining companies, vehicle and battery manufacturers, and other stakeholders—is complicated. As with so many other things, the pace of climate change only complicates efforts to combat it.

Another recent paper by Haochi Wu and Michael T. Craig from the University of Michigan’s Center for Sustainable Systems titled, “Climate change will reduce the durability of EV batteries globally” looks at how rising temperatures will degrade EV batteries by as much as 30%, with the Eastern United States identified as one region particularly vulnerable to these changes. There isn’t going to be an easy or painless solution.

Clearly, we need massive investment in both clean technology and in better transportation systems: buses, trains and other ways to get people out of their own cars.

But, in the short term, it’s clear that EVs are a significant improvement over regular gas-burning vehicles.