Experts at Which? said electric cars are a lot more expensive to buy, though they are generally cheaper to run as they plug in for their power from the domestic mains.
However, the amount of carbon dioxide created to generate the electricity powering an electric car can be just as great as that created by the internal combustion engine, reports the Daily Mail.
The main difference is that while a conventional car’s emissions come out of the vehicle’s exhaust pipe, those created by an electric car are generated at the power station, which supplies the electricity.
The findings come as the first ever electric car to pass the European crash test was announced—the Mitsubishi i-MiEVsuper-mini—getting four stars out of a maximum five.
Experts at Which? compared the carbon dioxide created by charging electric cars with that emitted by the most efficient diesel models and concluded that “sometimes there’s not a great deal of difference”.
And the gap is narrowing as “conventional” cars up their game to cut emissions.
“The common manufacturer claim that electric cars produce ‘zero emissions’ ignores the fact that most drivers use a conventional electricity supply to charge them, which has a carbon cost from burning fossil fuels,” the Which? report noted.
To test its theory, Which? looked at three of the first electric cars destined to hit the UK market and put them up against three “efficient” conventional rivals.
The experts found, for example, that the electric Smart Fortwo, expected to cost around £21,000, creates an “equivalent” of 84 gm of CO2 per km driven, whereas the £9,540- diesel Smart Fortwo emits 103 gm.
It also compared the Nissan Leaf, the £23,990-electric car, with Volkswagen’s diesel Golf 1.6 TDi Bluemotion costing £16,830.
The electric power generated to drive the Leaf is equivalent to CO2 emissions of 81g/km. By contrast, the diesel Golf has CO2 emissions of 108g/km.