Roof areas for the generation of energy
It does not matter to south, west, east or even a little bit towards north. Each roof surface, each partway sunny facade is urgent necessary for the generation of energy.
7500 kWh electric power per year and inhabitant is typical for high industrialised countires. Some consume can bei optimized, but on the other side, new consume by plug-in hybrid cars. This can be calculated like this:
This quantity estimation shows: The alibi solar collector on the roof, like a flag to show green convincing, is not enough. Also a roof with solar collectros is not enough. Even a roof with photovoltaic is still not enough.