Renewable reach of cars
The renewable reach is given in km of road performance per square meter of harvest surface and year. In addition the type of the harvest surface and the way from the harvest up to the tire.
Nowadays is biodiesel in Germany cheaper than Diesel. But this does not help, when only the car traffic would use up 300.000 square kilometers agricultural surface. 40 millions high efficient cars with 15,000 kms per year and 5 liters on 100 kms would use up almost the whole state surface for biodiesel monoculture.
Thus becomes already clear with the first calculation: It is necessary to yield much more per squaremeter than a rape field or sunflower field can deliver fuel. The most effective harvest surface for fuel is nowadays the photovoltaic. If we take again 40 millions economic cars with 15,000 kms per year and 18 kWh on 100 kms, there are only 1080 square kilometers.
No need to destroy the nature. A little bit what has place on the roof surfaces of the houses. It takes up 1 square meter photovoltaic with an about 300 times bigger agricultural surface if it is about the production of fuel.
This counts to electric cars, which in the transference chain of the photovoltaic about the battery to the electric engine and the tires. A much longer and inefficient way is fuel cell with hydrogen. Looses from the efficiency of the electrolyse to the efficiency of the fuel cell.