In addition to what @adrianN says about the laws (which is very true, these things are extremely easy to setup, install, and even to register despite the reputation of German bureaucracy), PV is also absurdly cheap.
We've got one. As per the law, limited to 800 W. €350 (of which €50 was delivery), including the inverter and the stands. As it happens, the stands weren't too useful for us (didn't fit our balcony so the panels are now on the driveway) and we could've reduced that to €250 if we'd gone for a model without stands and had been able to pick the kit up in person rather than getting delivered.
But even at €350, assuming 10% capacity factor, €350/(800W*24h*10%*€0.3/kWh*365) = 1.665 years = 1y8m.
Even if electricity was a third of the price, even with the €350 we spent, these things would still be no-brainers because they would still pay for themselves five to seven times over in their expected lifespans. As is, 15-21 times over.
That's irrelevant. The price is what one pays, whether that's residential, commercial, or industrial. Typically only industrial users have any negotiating power, and typically residential customers are the only users who aren't able to claim the expense as a business operating cost.
There's an argument to be made that in a democracy the people could vote themselves lower taxes, but if that were the cast why haven't they already.
Subsidies are paid for by tax payers anyway, so, ya know, TANSTAAFL - There Ain't No Such Thing As A Free Lunch. And there's no guarantee subsidies survive the next election.
Germany in H2 2024 was at €0.3943 per KWh including standing charges [0], so not quite the right number when evaluating whether balcony solar is worth it.
