Replacing a gasoline car of any age—even a brand-new one—with an electric vehicle will almost always lower overall carbon emissions, according to a new analysis. The findings resolve a key conundrum about making the switch from gasoline to electric vehicles, the researchers say.
Driving an electric vehicle (EV) produces less emissions than driving a gasoline car, and the disparity is growing ever wider as electric grids decarbonize. So it has been obvious for a while that if you’re in the market for a new car the best choice for the environment is an EV. But manufacturing an EV produces more emissions than manufacturing a gasoline car, and this has led to uncertainty about the break-even point.
That is, if you own a gasoline car that works fine now and are considering when to replace it with an EV, should you drive the gasoline car into the ground, staving off the hefty emissions burden of EV manufacture for as long as possible? Or should you replace it as soon as budget allows, and start to reap the benefits of the EV’s much lower operating emissions?
“Even if you scrapped a new gas car, the EV still wins,” says study team member J. Elliott Campbell, chair of the environmental studies department at the University of California in Santa Cruz. “The environmental advantage of EVs is now crystal clear.”
Campbell and his collaborator Roland Geyer, at the University of California in Santa Barbara, calculated the life-cycle carbon emissions of keeping a gasoline car on the road for 16 years (the typical lifetime of a passenger vehicle) compared to replacing it with an EV.
They considered many different vehicle types and timelines for replacement, as well as electricity sources, individual driving habits, battery size, and other parameters.
Replacing a gasoline car with an EV makes climate sense across a broad range of scenarios, even when the gasoline car is new, the researchers found. Of course, that won’t be affordable for most people. But it’s a stark illustration of the climate benefits of EVs.
In the analysis, climate benefits were generally greatest when gasoline car was scrapped in year 1, leading to an average 58% reduction in emissions over the 16-year period. It takes about three years of driving an EV to make up for the greater emissions involved in manufacturing it.
“I was shocked that even scrapping a hybrid gives big climate benefits,” Campbell says.
In 92% of the scenarios the researchers ran, replacing a gasoline car or hybrid vehicle with a battery electric vehicle before the end of its lifespan reduced overall carbon emissions. The exceptions: scenarios involving the least efficient EVs drawing power from the dirtiest electric grids; plug-in hybrids; and gasoline cars that are driven very few miles annually.
The energy mix of local electricity grids can shift the break-even point. But across most of the United States, it’s worth replacing even the most efficient gasoline cars early. And for the most common gasoline car models sold in the United States, early replacement makes climate sense even in areas with the dirtiest electric grids.
The benefits of switching to an EV will become even greater in the coming years, as electric grids decarbonize and battery recycling technology improves, which will decrease manufacturing emissions associated with EVs.
Campbell is now working on an analysis of the mass of materials involved in EVs compared to gasoline cars. “An EV has a 0.5 ton battery but a gas vehicle can use 20 tons of petroleum in its life,” he says. Batteries can be recycled, “but once you burn petroleum it’s essentially gone forever. I think more work needs to be done to explore this material advantage for EVs.”
Source: Campbell J.E. and R. Geyer. “The climate benefits of retiring a fully operational internal combustion engine vehicle.” Science 2026.
Image: © Anthropocene Magazine.
