But the north side hardly gets any sunlight, so how could it still be worthwhile? Sorry for the stupid questions, but I had actually not dealt with this topic at all before.
The chimney can no longer be relocated because it is a "shaft" for a gas fireplace and it is located where the fireplace will be. In the north, the chimney would run centrally in the hallway on the upper floor.
Maybe I could have the roof exit window moved to the east, so that only the chimney remains there. The question would be whether it makes a difference whether it is there or not.
To decide whether the north side can be worth installing, two things must be done:
a) Simulation of the yield of this roof area
b) Project the result from a) with the feed-in tariff over 20 years and compare this value to the costs of installing the north side (the savings effect from self-consumption of the electricity is not yet included).
You can get a first estimate of the yield via pvgis, just search for it.
If a module would fit on the south side instead of a roof exit, relocating would of course be worthwhile, ideally of course to the north side.