By David Wilkins
Monday, 28 September 2009
Volvo has said it wants to introduce plug-in hybrid cars from 2012.
Standard hybrid cars have both an electric motor and an internal combustion engine. Energy that would normally be lost under braking is directed towards recharging batteries which are then used to power the electric motor, which kicks in to support the combustion engine under acceleration. Some hybrids are able to run for very short distances at low speeds on battery power alone.
Plug-in hybrids, which as their name suggests, can be charged from the mains while the car is stationary, are able to spend a much greater proportion of a given journey running on electric power; Volvo says that its plug-in hybrids will be able to run for up to about 30 miles on batteries alone. Only beyond that distance, which, according to Volvo, covers the daily needs of about 75% of European drivers, does the combustion engine – in this case, a diesel – play a part.
A diesel plug-in hybrid can be an exceptionally economical and ecologically friendly car but the precise advantages depend on a number of factors, in particular, which fuel is used to generate electricity at the power station, but Volvo thinks its cars will achieve a range of 745 miles while emitting as little as 50g/km of CO2 and consuming as little as 148.6mpg.