American cars will emit 30 percent less carbon dioxide by 2016. On this theme, Harry Frank from the Energy Committee of The Royal Swedish Academy of Sciences has made some calculations on the forecasts for the future of the combustion engine and the electric engine.
 
There is only limited access to bio raw materials, which means that it has to be used in the best way possible. I have therefore had some fun calculating how effective it would be to use a square metre of land for energy cultivation.
 
My calculations show that two decilitres of ethanol can be extracted from a surface equivalent of one square metre of wheat-cultivated land in Sweden. This ethanol can then be used to run a private car with a combustion engine for two kilometres a year.
 
A solar panel cell on a similar surface, using current technology, will give 100 kilowatt hours of direct electricity in Sweden per year. A private car with an electric engine could then be driven for 400 kilometres per year.
 
New research findings show that one solar cell can increase efficiency by as much as three times compared with current solutions per square metre. This would mean that an electric car would have a driving range of as much as 1,200 kilometres per year for every square metre of solar cells.
 
This result not only shows how much better it is to ‘cultivate’ electricity directly, but also how much more efficient an electric engine is than a combustion engine. The efficiency of an electric engine in an electric car is around 90%, compared with a petrol or ethanol-powered combustion engine that has an efficiency of around 20-25%. A diesel-powered combustion engine has an efficiency of around 30%. Electric engines are therefore much more effective than combustion engines.
 

Written by Harry Frank
Energy Committee of The Royal Swedish Academy of Sciences

Private cars in Sweden emit around 12 million tonnes of carbon dioxide, i.e. 60% of road traffic emissions.
Light lorries in Sweden emit around 3 million tonnes of carbon dioxide, i.e. 15% of road traffic emissions.
Heavy lorries in Sweden emit around 5 million tonnes of carbon dioxide, i.e. 25% of road traffic emissions.
Private cars and light lorries will have an electric engine in the future and together, these account for 75% of road traffic emissions. Transport by heavy vehicles will be taken over by rail transport.
The figures are taken from the Vehicle 2008 report from the Swedish Institute for Transport and Communication Analysis  Fig 3.1