To give a reference in France an average vehicule is driven 13000 km/year which is around 2 MWh with typical 150 Wh/km. A parking spot is around 2.5 x 5 meters

To give a reference in France an average vehicule is driven 13000 km/year which is around 2 MWh with typical 150 Wh/km. A parking spot is around 2.5 x 5 meters, solar panel efficiency is about 20%, in France we get about 1000 hours equivalent full sun per year so a parking spot covered with solar panels will produce 2.5 MWh each year. Of course not enough in december and too much in june, but that gives an easy figure to remember. Solar panels don't produce that much energy but electric cars are very efficient devices. Another statistics about France : there are about 2 to 3 parking spot per car in the country.