Petrol and diesel engines will remain 'unchallenged' in the private car market for at least the next 20 years, according to automotive supply company Bosch.
An electric motor is the most efficient means of powering a car, but Bosch says there are 'important technological challenges' to be overcome on the way to mass electrification, and that manufacturers who claim otherwise are making 'unrealistic forecasts'.
However, Bosch believes that the fuel economy and CO2 emissions of petrol and diesel engines can be improved by around a third while it continues to develop electric drive systems.
Dr Rolf Leonhard, the company's vice-president in charge of diesel systems, says Bosch technologies will allow medium-sized cars to do 94mpg with CO2 emissions of only 70g/km within a 'few' years.
Pulling the plug on fossil fuels
With more than 60 cities expected to have populations of at least five million by 2015, Bosch is convinced that electrification is the best solution for urban transport in the long term, however.
The two biggest challenges are to reduce the weight and cost of battery systems. Currently, an electric car with a range of 125 miles would have to carry 250 kilos of batteries costing around £15,000. This figure might be cut to £10,000 by 2015, but that is still too expensive, says Bosch.
It is calling on manufacturers in Europe and America to follow the lead of the Chinese and Japanese and co-ordinate their resources so that entire cars can be designed around standardised electric drive systems to help bring down costs.
'By 2015 we expect to see a sales volume of some 500,000 electric vehicles worldwide,' says Dr Bernd Bohr, Bosch's chairman. 'But to achieve these volumes, we must first improve the performance of these vehicles.'