Last week TheGreenCarWebsite.co.uk reported on Which? ‘allegations that electric cars are no cleaner than their combustion counterpart’ (see story). Here Richard Headland, editor, Which? Car replies.
The full article, ‘Electric Cars’, available in the March edition of Which?, describes the advantages and disadvantages of electric and diesel cars. You can also view the results from this article on the website (www.which.co.uk/cars/choosing-a-car/eco-cars) and see that we do acknowledge the full emission advantages of EVs.
However, when we compared the carbon dioxide created by charging electric cars with that emitted by the most efficient diesel models, we found that sometimes there’s not a great deal of difference.
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.
We looked at three of the first electric cars destined to hit the UK market and put them up against three efficient conventional rivals. We found, for example, that the electric Smart Fortwo creates an equivalent of 84 grams of CO2 (created by charging the car) per kilometre driven, whereas the diesel Smart Fortwo emits 103 grams.
The Carbon Trust states that 544 grams of CO2 are emitted per kilowatt hour of electricity used. We converted this to an equivalent grams per kilometre CO2 rating, to make it easier to compare with the diesel cars. This is a figure calculated from fuel (coal, gas etc) burned in power stations, and accounts for losses between the plant and a domestic mains plug. It does not account for the extraction, refining and distribution of fuel to those power stations.
Similarly, our CO2 figures for the diesel cars we tested (at a rolling road) are for fuel burned in the car. They do not include extraction, refining and distribution of the fuel to petrol stations. In this way we’ve tried to achieve a ‘like for like’ figure for electric and diesel cars.
Obviously we appreciate there is a wider picture to CO2 emissions, as the ‘well to wheel’ figures imply. However we have yet to find robust figures to account for these emissions, both in terms of fuel supplied to power stations and fuel supplied to petrol stations.
If you know of any independent, unbiased figures that could help us with this, we’d love to hear about them.
We also point out in our article that electric cars are much greener than diesel cars when it comes to localised emissions, as they don’t emit toxic chemicals that degrade air quality. We recognise that this is especially significant in cities, where the uptake of electric cars is predicted to be highest.
We applaud carmakers’ efforts to create greener cars – but we don’t agree with their ‘zero emissions’ claims. Until more electricity is produced from renewable sources in the UK, the carbon footprint of driving an electric car may not be as small as owners think.
So what do think of Which?’s report. Is it a fair assessment of electric cars? Let us know by leaving a comment below.
