Is a photovoltaic system with storage and additional solar required?

He means solar thermal energy.

The statement is nonsense.

A KfW Efficiency House 40 Plus meets the requirements of a KfW Efficiency House 40 and includes the following plus package:
• A power-generating system based on renewable energies
• A stationary battery storage system (electricity storage)
• A ventilation system with heat recovery
• A visualization of power generation and power consumption via a corresponding user interface

I would reconsider that with KfW. I just noticed that the loan conditions have worsened again. The repayment grant no longer really helps to make up for that.

Hello,

I have had the KfW loan for a long time, but there is nothing written there about needing solar thermal systems for domestic water heating and a power storage system, so in my opinion, it would be sufficient to just install the power storage, right?

It states that a renewable share must be present... no more and no less...

... and what does that mean? That I either store electricity or domestic hot water geothermal energy. Right?

I already have the KfW loan, but it does not say anywhere that solar thermal systems for domestic hot water heating and a power storage system are required, so in my opinion it should be sufficient to just install the power storage system, right?

That's correct. But read the regulations regarding the capacity of the power storage system again. This depends on the sizing of the photovoltaic system or the living area. You might have miscalculated there. However, for all of this you also (necessarily) have the energy consultant who tells you what is right and wrong.

You don't need to worry about the renewable share if you are talking about KfW 40+ anyway, because controlled residential ventilation with heat recovery is mandatory and fulfills the renewable part.

All of this is also answered by the generously paid, KfW-accredited energy consultant :)

The storage is economically nonsense as well, but if you want to have something like that, of course you can do it.