Heating not available - Who bears the costs?

Why should you do that if the heat pump is already installed? Ours has a special screed drying program, it ran completely normally.

It runs partly with the electric heating element in the screed program. But probably not 1:1.

I can't help it in retrospect that the ordered heating system is not being delivered,
the general contractor also receives "compensation" from the trade for the delay compensation to us, right?

We don't know what your general contractor has agreed with his subcontractors. But that's also irrelevant at this point. What matters is what you have agreed. Your general contractor only gets into delay if the house is not finished by the end of the construction period. Only then can you also claim damages. Until then, your only "instrument" is to withhold partial payments. But that has to be looked at more closely on a case-by-case basis.

Construction electricity comes from the client,

That is exactly your risk, just as it is the risk of the general contractor to possibly get into delay. Of course, you can take action against the general contractor if it turns out that he did not handle your electricity sensibly, for example, if the trades consumed 1,500 kWh for a bumper car (photos as evidence are then not wrong). If your general contractor sets up a mobile heater for you as a bridge and still manages to deliver and install the heat pump by the end of the construction period, then you will have to swallow that bitter pill—no matter what the meter reading may be.

In the end, you are better advised to find a solution for the problem "heating system not deliverable" together with the general contractor instead of philosophizing about damages. If Nibe can deliver another heating system faster, then suggest that to the general contractor. However, it is at his discretion whether he does so or not and whether you then conclude a change agreement to the construction contract or not, because—as said—the important thing is that the house is finished by the handover date.

We also want to mention that GU is interested in a sensible solution, I just wanted to put the question out there and I could already guess the answers. The last statement from the Hotboys was also that we would agree on the electricity costs. Confirms my impression so far that we made a good choice.

Don't really underestimate what the screed program with a heat pump costs. We had ours last time in the middle of summer, and it still consumed over 1000 kWh I think.

Don't really underestimate what the screed program with a heat pump costs.
We had ours last time in the middle of summer, and it still consumed over 1,000 kWh, I believe.

1,000 kWh? My neighbor burned almost 4,000 because he had to heat only with his 17.5 cm rear wall brick "toothpick" walls instead of an ETICS. But admittedly, it was also in spring, not in summer.

We had ours last time right in the middle of summer, and it still consumed over 1000 kWh, I think.

At an electricity price of 40c, that’s still just about 400€. A heat pump with a screed program would maybe be 150€. Even if you double that, it’s not a big deal. This is a category of problems that you address politely and keep for the final invoice if the solution is unsatisfactory.