I take it greewhizz is one of this new car clubs? I thought about joining the scheme as well but I am not sure its good for shool run, given the fact that you need to go to the depot to collect the car each time you want to use it.
You see quite a lot of them down here in London as they are exempt from the congestion charge. They are quite expensive for what they are and they need to be serviced quite often.
If I am not mistaken, GM is coming up with the new volt next year that is an electric car and if I am not mistaken its a plug in that charges overnight. Lets just hope that GM stays in business long enough to produce and sell this car! :)