Retire your gas-burner now to maximize pollution reduction

The anti-EV crowd has an endless repertoire of specious arguments designed to convince EV-curious drivers to continue burning gas just a little longer. One of these is the idea that, because building a new car has a carbon footprint, it’s greener to hang on to your old gas car than to replace it with a new EV.

Sounds logical, right? Maybe, but the facts tell a different story. New research from the University of California Santa Cruz finds that replacing a legacy ICE car with an EV as soon as possible yields the greatest possible climate benefits.

While it’s true that the carbon footprint of producing an EV is higher than that of a legacy vehicle, this “carbon backpack” will be cancelled out within a few years by the EV’s lower well-to-wheels emissions. Several studies have found that an EV will produce lower emissions over the life of the vehicle. (See the EPA and Carbone4 for links to some of the relevant studies.)

The UC Santa Cruz researchers found that it typically takes about three years for the lower emissions of driving a battery-electric vehicle to offset the emissions required to produce it. Furthermore, switching from an ICE to an EV within the first year of the gas car’s life will result in a 58% reduction in carbon emissions over a 16-year period.

As UC’s Allison Arteaga Soergel writes, “From a carbon emissions standpoint, you’d be better off sending a brand-new internal combustion engine car directly to the scrap heap in order to replace it with a battery-electric car.”

Of course, the researchers don’t recommend scrapping a car you just bought—the greenest choice isn’t always the smartest financial move. But for drivers who are in the process of considering a purchase, the new study, published in the journal Science, makes the sustainability case for EV ownership clear.

“This is really a definitive study about the carbon emissions benefits of EVs, because it shows that even in such an extreme scenario, the EV is still the obvious winner,” explained UC Santa Cruz Environmental Studies Professor Elliott Campbell, lead author of the paper. “So if you’re trying to decide whether or not to put money into keeping your gas car going, switching to an EV as soon as a financially viable opportunity comes up is absolutely the right thing to do for the environment.”

Campbell developed the idea for the current study in the course of interviewing people about their perceptions of EVs. “This question of when to retire your current vehicle kept coming up,” he says.

Campbell found that research about this specific question was lacking. “Keeping gear going makes sense in so many contexts, but not in every context. Sometimes it’s better to make a shift to a newer, more efficient option, and it wasn’t clear yet which was the case with transitioning to an EV.”

Campbell and his coauthor, UC Santa Barbara Professor Roland Geyer, compared different timelines for replacing an ICE vehicle with an EV. They calculated the percentage difference in emissions that would result if a gas-powered vehicle was driven for its full useful life (about 16 years), or scrapped and replaced earlier.

They looked at how carbon emissions for more than 400 ICE and BEV models were affected by different vehicle efficiencies, grid electricity sources, vehicle mileages, and EV manufacturing emissions and battery sizes.

Their results showed that the climate benefits were generally greatest when gas-powered vehicles were retired at year one, resulting in a 58% reduction in carbon emissions over a 16-year period. It typically took about three years for the lower emissions of driving a battery electric vehicle to offset the emissions required to produce it. The climate benefits added up quickly from there.

“What it comes down to is that gas vehicles require so much more energy to operate,” Campbell explains. “Only 20% of the energy in the gasoline that most of our cars burn actually goes toward moving the vehicle—the rest is lost as heat. So it really puts internal combustion engines in a totally different class than EVs when it comes to efficiency, and that leads to a situation where you want to retire the gas-powered vehicle as soon as you can.”

The exact benefits of retiring any particular ICE vehicle vary based on location and the specific type of vehicle. But 92% of the scenarios that researchers modeled for replacing gas-powered or hybrid vehicles with battery-electric vehicles before the end of the vehicle’s useful lifespan achieved at least some overall reduction in carbon emissions.

Meanwhile, a recent MIT study has added to the existing pile of studies debunking the Long Tailpipe myth—the idea that driving an EV simply displaces emissions from the tailpipe to the power plant. The latest research, published in Environmental Research Letters, found that, despite regional differences in climate, electricity sources, traffic and driving patterns, EVs produce fewer greenhouse gas emissions, and cost no more to own, than comparable gas-powered cars for most US drivers. Even the dirtiest US grid fails to make an EV the more polluting option. And of course, electrical grids around the world are becoming greener over time, whereas a gas car burns the same fuel for the rest of its life.

Source: UC Santa Cruz