In a straight choice between a new petrol car and a new electric car, on climate grounds the electric car wins easily.
But what if your existing petrol car is still working fine 鈥� or is even only a year or two old? Contrary to popular belief, the overall climate impact is lower if a new petrol car is scrapped in favour of an electric vehicle (EV), new research reveals.
Studies show that although EVs produce more carbon emissions when they are manufactured, they are responsible for much lower emissions when they are being driven compared with a petrol or diesel car. Overall, the whole-life emissions for an electric car than for combustion engine vehicles.
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at the University of California, Santa Cruz and at UC Santa Barbara wanted to find out whether drivers should wait until their current combustion engine car is ready for the scrapheap before moving to electric.
Using US data, they analysed the emissions impact of scrapping a fossil fuel car and replacing it with an EV at different points, from scrapping a car that is just a year or two old to one at the end of its life. Their modelling accounts for the emissions associated with producing and running a new electric car, and other factors including variability in the grid electricity mix, vehicle efficiency, manufacturing emissions and mileage.
鈥淲e found that in the vast majority of cases, and even for a brand new gas vehicle, you would be far better off scrapping the gas vehicle and switching to electric,鈥� says Campbell. 鈥淚t takes more energy to build an electric vehicle, but the savings from driving the vehicle swamp all the upfront costs.鈥�
Campbell stresses he doesn鈥檛 expect people to immediately scrap their brand new cars. Instead, the study aims to show that there is zero environmental benefit in keeping a fossil fuel car on the road until the end of its life.
The findings hold true for almost any scenario, except where an electricity grid is very reliant on coal power, or when a fossil fuel car is driven less than about 7000 km per year.
鈥淭he idea here is just to simply show what a huge advantage electric vehicles offer, so that when the opportunity to make the transition [is] something that people are ready and excited to do, by all means go for it,鈥� says Campbell. 鈥淭here鈥檚 no environmental concern to hold you back.鈥�
at the Yale University says the paper takes a 鈥渃lever angle鈥�. 鈥淚 think what they鈥檙e talking about makes perfect sense. I鈥檝e thought about this before [but] I鈥檝e never thought to write a science paper on it, and I鈥檓 impressed.鈥�
But at the University of Michigan points out that the study is considering an 鈥渆xtreme case鈥�. 鈥淚t鈥檚 unlikely somebody鈥檚 going to purchase a combustion engine vehicle and retire it after a year,鈥� he says.
Instead, those cars will likely hit the second-hand market, which could have knock-on economic and behavioural impacts, such as lowering the price of second-hand cars so dramatically that it convinces more people to switch from public transport to car use. More research is needed to model those potential impacts, says Campbell.
But the study鈥檚 authors say their findings lend support to the idea of subsidised scrappage schemes, to encourage people to scrap older fossil-fuel cars in favour of electric vehicles. Such policies could accelerate the EV transition in the US and help to cut transportation emissions, which are now the single largest source of carbon emissions in the country.
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