Balcony solar panels isn't necessarily a bad outcome. It's enormously more resilient to natural disasters and warfare than centralized power stations, it's potentially more responsive to individual power needs than an electric regulator, and it may not even be inefficient—while solar panels in a utility-scale solar farm will have a higher capacity factor than balcony solar panels, that only saves you money on solar panels, but requires transmission, distribution, metering, and utility-scale storage capacity between the solar farm and the apartment, all of which are costly. At some price point, putting up a solar panel costs less than running a power line to your house.

With "mainstream" solar panels costing €0.100 per peak watt as of August (according to https://www.solarserver.de/photovoltaik-preis-pv-modul-preis...) it's getting harder and harder to justify the efficiencies of centralization.

That is, maybe with single-axis trackers and optimal angle, your solar farm gets a capacity factor of 15% (I think Germany's average for utility-scale solar is 10%) so an average 500-watt load requires 3300 peak watts of utility-scale generation (€330), plus 3000 additional watts of inverter capacity, 2000 additional watts of storage capacity, 1000 additional watts of transmission capacity over something like 100km, and 1000 additional watts of distribution capacity. Maybe your capacity factor on the balcony is only 7.5%, so you have to spend €660 for 6600 peak watts, and you probably still need some storage capacity, so maybe you end up spending €1000, €670 more than the solar-farm panels. Maybe you need to spend €80 on a 12-volt car inverter, too.

It's very easy for the cost of utility-scale inverters, transmission capacity, etc., to exceed the €750 savings you get in this case from centralization. Also, note that about 20% of the energy produced in utility-scale generation is lost in power conversion, transmission, etc.

Note that I'm only talking about costs here, and only about the essential costs that come from the form of production. I'm not talking about prices, which may incorporate subsidies, permitting costs, taxes such as tariffs, transaction costs, lawsuits against non-performing building contractors, and market inefficiencies such as homeowners not having access to the zero-marginal-cost excess power that can be produced on sunny days for regulatory reasons.