You are are squabbling about efficiencies and greenness but what i see is a chance to escape the punative taxes that are in each gallon of petrol. Drive past the petrol station and get one over the tax collector.
Oh. If you had solar panels on your garage roof or a wind turbine then just imagine.

Richard Tucker, Cotter, USA

A diesel engine has a thermal efficiency of approx 40%, and a petrol engine of about 25%. Mains electricity is about 18% of what went in at the power station. The efficiency of the charger and the electric motor must be < 1, say 0.8 so the total efficiency off an electric car is about11.5%. Green?

Bob, Cowes, UK

Adam of London is 100% correct.

It has been suggested that the "greenest" car you will ever run is the one you presently own.

New cars and hybrid cars -- more profit for the automotive industry and more tax for the worlds governments and more unavoidable (avoidable?) manufacturing pollution.

steveh, Halesworth, Suffolk, England

Ben A: a car is 15% efficient (E), half wasted on braking leaving 8% E. Electric vehicles are 80% E so are 5-6 times more efficient. Power stations have huge economies of scale so are 30%E 30*80% = 24%E which uses less fuel & signifigantly reduces co2 - cars omit 21% of global co2 emissions today.

Matt S, London, England

I can see the point of hybrid cars that charge as they drive along - they would've been driven anyway, so there's no unnecessary pollution.

What, though, is green about plugging a car into the mains to charge up when a large amount of mains power is derived from polluting power stations?

Ben A, Manchester,

How green is it to buy a brand new car made from over a tonne of new steel?

Especially when it contains a 30kg lithium battery?

Adam, London,

You just know everyone will be plugging in at work . Forget about stealing photocopier paper and paper clips - free fuel !

mike, London, UK