According to my calculations and the studies I've read, it would be enough to cover some single digit percentages of Germany with solar panels to meet its energ

According to my calculations and the studies I've read, it would be enough to cover some single digit percentages of Germany with solar panels to meet its energy (not electricity!) demand. Certainly less than 5% of the land. You get most of the way there just by using the agricultural area currently in use for "energy crops" (corn for ethanol, canola for diesel, etc, 2.4 million hectares in Germany). Germany is not terribly well suited for solar either. Wind is a bit better from a kWh/m^2 point of view.