New Science Says Scrapping A Working Gas Car For An EV Is Usually Greener

A new study in the journal Science pushes back on the idea that keeping a working gas car running is always the greener choice than replacing it with an electric vehicle. Researchers J. Elliott Campbell and Roland Geyer compared the two options across many scenarios and found that in 92% of cases, retiring a working gas vehicle early and switching to a battery EV cut emissions overall, once you account for all the future gasoline the old car would burn. For a typical SUV on the average US electric grid, replacing it in its second year cut cumulative emissions by 44% over 16 years. The extra emissions from building the new EV were paid back in about three years.

The benefit depends heavily on how much a car is driven and how efficient it is, more than on how the EV's battery was made. The study found mileage thresholds below which switching doesn't pay off environmentally: roughly 7,000 km a year for cars, 6,800 km for SUVs, and 10,800 km for trucks. Lightly driven cars, efficient hybrids, and EVs charged from especially dirty power grids are poor candidates for early replacement.

For homeowners, the takeaway is less about your house and more about your driveway: a high-mileage gas pickup or SUV is a much stronger candidate for early EV replacement than a car you rarely drive. The study also flags a side effect worth knowing — scrapping working cars early can shrink the future supply of affordable used vehicles for lower-income buyers.