Construction costs are currently skyrocketing

Two milkmaids are a calculation. Or do you like sitting in the dark in winter evenings?

No. That's why wind power is needed. And if you think there isn't enough wind, you haven't read any scientific studies on the subject. Among others, I've mentioned Fraunhofer here several times. Again: It is not a problem to generate all energy (including for transport and heating) IN Germany ONLY with wind and sun. With existing technology. Within 10 years. And in the end, it is even cheaper. And one more thing: With a bit of international grid expansion, the whole thing can even work without storage. Sounds crazy. But it's true. ;-)

That is connected in several ways.
The requirements for energy-saving houses make building more expensive per sqm regardless of inflation.

I don't think so. My thesis: only the margins for the construction companies are increasing.
Building plots are the limiting factor, not the energy saving ordinance requirements.

The energy saving ordinance requirements therefore exist at zero additional cost compared to without the energy saving ordinance?

Of course, requirements to be met are more expensive than not having to meet them. That does not exclude price effects for other reasons.

Why can't people be forced to install a photovoltaic system on the roof when building new houses? The Energy Saving Ordinance is already a requirement that must be met. And when I look at the other regulations, it would only be a piece of cake in terms of costs. In addition, a photovoltaic system is one of the few investments that pays off over the years. People build a double garage, want to have 200 sqm+ for two people at best, but a photovoltaic system, no, it's just too expensive....

I am definitely not a Green voter, but in this case, I would be in favor of compulsion.

Is that already in place from 2022 in BW, or am I mistaken?

Why can't people be forced to install a photovoltaic system on the roof when building new houses? ..... I am definitely not a Green voter, but in this case I would be in favor of compulsion.

too many uncertainties:

a relatively high proportion of (smaller) buildings will increasingly be affected by shading problems. Then one would come to the absurd alternative of cutting down trees (microclimate! problem) so that the photovoltaic system gets enough sun.

therefore, there would have to be an exception management (expert) who re-certifies each object every few years (compliance with requirements).

I see the problem more in the political arena: politicians do not dare to decree a photovoltaic grid feed-in priority against the utility operators so that the grid can serve as a load buffer. That is why today, for example, it is forbidden to simply feed one’s own excess electric power from photovoltaics into the grid (meter runs backwards) and have the utilities only produce the missing difference. This is not a (often claimed) technical problem (alleged grid instability) but can be easily controlled through certified decentralized on-grid management.

too many uncertainties:

a relatively high proportion of (smaller) buildings will increasingly be affected by shading problems.
Then one would come to the absurd alternative of cutting down trees (microclimate! problem)
so that the photovoltaic system gets enough sun.

therefore there would have to be an exception management (expert),
who re-certify each object every few years (compliance with requirements).

I see the problem rather in the political arena:
politicians do not dare to decree a photovoltaic grid feed-in priority against the utility operators,
so that the grid can serve as a load buffer.
That is why today, for example, it is forbidden to simply feed one’s own excess electrical power from photovoltaic into
the grid (meter runs backwards) and the utilities only produce the missing difference.
That is not a (often rumored) technical problem (alleged grid instability),
but can be easily controlled by certified decentralized on-grid control.

But shading simply means producing less. We also build in Brandenburg. In Bavaria, the sun shines more and people get more benefit from the photovoltaic system.

That is no reason for me.