Hollywood loves the Toyota Prius for the green image it purveys to celebrities who have a carbon footprint several times that of the average citizen. Middle England loves the Toyota Prius because over a dinner party they can tell their neighbours they drive a hybrid car. I even like the Toyota Prius because it has raised awareness of hybrid technologies to the world, and brought them into the public consciousness. But is it as green as Toyota claim?
Well, the official CO2 figure for the Prius is 104 g/km, which is equivalent to 62.8 mpg (although Toyota actually claim 65.7 – someone in Japan has their maths wrong there). Now DEFRA in their guidelines to the carbon offsetting quality standard (which is soon to be released) says that reported g/km “factors must be uplifted by 15% to take into account ‘real-world’ driving conditions”. This is not Prius-specific, but does admit that even the government doesn’t believe the CO2 figures they use to tax us on.
With this uplift, the Prius would now be at 119.6g/km (54.6 mpg) which on the face of it seems more reasonable. In independent tests the Toyota has also failed to live up to its claimed efficiency, with What Car (1) recording 52mpg, The Sunday Times (2) recorded 48.1 mpg on a long journey and owners typically reporting between 53 & 54mpg. This gives us a worst of 48.1mpg and a best of 54mpg. Translating that into CO2, that’s 121 to 136 g/km of CO2. So not bad, but still 16-31% higher than Toyota claim (104 g/km) and very misleading.
It’s also worth remembering that a hybrid engine is only beneficial for lots of stop start driving. Running at constant speed there is no benefit over a normal engine, and in fact a disadvantage because you are carrying the extra weight of unused batteries and motor. It’s also worth noting that fuel consumption (and hence CO2) is all about your driving style and not what you drive. 91mpg was achieved by a chap called Will from Warwick Uni (3) in a VW polo Bluemotion, in excess of the claimed 74.3mpg and that included traffic on the M25. A Prius will also cost you more than an equivalent non-hybrid car, and the extra money you spend will take a long time to recoup (if ever). And if you were thinking about buying one to replace your old car, remember that means that somewhere another vehicle needs to be manufactured with all the raw materials that entails.
So, if you want to show people you care about the environment, enjoy looking smug at dinner parties or star in Hollywood blockbusters, then the Prius is the car for you. If you simply want to save fuel & money, lower your carbon footprint and actually do something for the environment, then improve your driving style and follow the example of Will from Warwick.
(1) www.mailonsunday.co.uk/news/article-399074/The-great-mileage-rip-off.html
(2) http://www.timesonline.co.uk/tol/driving/used_car_reviews/article3552994.ece
(3) http://blogs.warwick.ac.uk/nho/entry/911_mpg_in
Source: Clear analysis
