I don't have numbers unfortunately. All I can say is that photovoltaic is the default rather than the exception for new buildings and that all people I know with photovoltaic talk very highly about the returns.

Obviously in more southern countries it works even better and countries in scandinavia will have less returns. I think photovoltaic is pretty much nonexistent in Norway or Sweden for example. But from what I know, photovoltaic is a riskfree, profitable investment here.

I'm not sure how widely it is known, but Germany has been the worldleading producer for photovoltaic around ~2010 thanks to the subsidies by the past progressive government until - as always - Merkel and other corrupt conservatives destroyed the industry with over 100.000 workers shortly before it became profitable by itself by cutting all of the funding.
If people had been smarter in the past elections, this whole current mess would have been very different and maybe Putin wouldn't even have dared to wage war because Germany would have been way more independant of their energy supplies.

Photovoltaic works absolutely fine in germany. Pretty much every new building has it. The only reason we are behind our plan for renewables is because people were dumb enough to vote conservatives into government for 16 years until last year.