This 'infographic' from carinsurance.org neatly shows that the expensive electric car you are thinking of buying to do your part in saving the planet may not have quite the impact you think it will.
Infographic no longer available.
As it points out an eco-car will be friendlier on the environment depending on which US city it gets its energy from.
Some interesting stats:
It took a quarter of the world's trees to absorb car emitted CO2 in 2010. That's 68 billion trees sucking up 3.4 trillion pounds of CO2.
The average electric car is 80% efficient as opposed to the 20% of a diesel car or the 15% of a petrol driven vehicle.
But, because they rely on the local power station for their energy, an electric car in LA has an equivalent CO2 output of a traditional car that gets 79 mpg, whereas an electric car in Kansas would be the equivalent of a 35 mpg petrol powered car.
The greenest area for electric cars would be Juneau (112 mpg) and the worst Denver (33 mpg).
The message is, if you invest in an electric car then make sure you know where to plug it in to make it as green as possible.
Image by Kirill Borisenko (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons