In case you get your green wheel options mixed up, here are some simple definitions starting, of course, with our favourite option.
Electric vehicle - a vehicle driven entirely by an electric motor powered by a rechargeable battery that is usually plugged in overnight
Hybrid - a vehicle containing both an electric motor that recharges itself from kinetic energy and a petrol-powered internal combustion engine
Plug-in hybrid - a hybrid that can be plugged in to an electrical outlet to charge its battery
Flexible-fuel vehicle - a vehicle that can run on a blend of petrol and alternative fuels, usually ethanol
Ethanol-powered vehicle - a fuel that burns cleaner than gasoline and usually is produced from grains like corn, wheat and barley
Biodiesel vehicle - usually a mixture of conventional diesel fuel with renewable resources like soya bean or rape seed oil or waste animal fat
Hydrogen-fuelled - this element can power fuel cells and is touted by some as the zero-emission fuel of the future, though it faces technical and distribution obstacles