Offer comparison and liquidity planning for new construction, any experiences?

Photovoltaics are mandatory here, and we would purchase an electric car with the house. Whether the photovoltaics and storage really need to be that large is another question. But based on the current calculations from websites, I arrived at the values with our current consumption.

[*
Acquisition cost of the battery:


[*]On average, photovoltaic storage systems cost about €800–1,200 per kWh of capacity. For a typical single-family house, a 5 kWh storage system is often chosen.
[*]At a price of about €1,000 per kWh, a 5 kWh storage system costs around €5,000.


[*]Electricity price and savings:
[LIST]
[*]The average electricity price for households in Germany is about 30–35 cents per kWh. Assuming the electricity price remains constant in the long term (which is rarely the case), and one can additionally consume about 1,000 kWh annually through the storage system itself.
[*]This results in savings of about €300–350 per year.


[*]Feed-in tariff:


[*]The electricity that would be fed into the grid without storage also generates income through the feed-in tariff (currently about 8–10 cents per kWh).
[*]The additional self-consumption thus reduces the saved grid electricity price by the feed-in tariff. Instead of 30–35 cents, the actual savings are about 20–27 cents per kWh.


[*]Payback period:


[*]Under these assumptions, the battery saves about €200–270 annually.
[*]At a price of €5,000, this results in a payback period of about 18 to 25 years.

Just wait. Prices in the West German metropolitan regions will soon collapse drastically. We are currently sliding into an existential economic and liquidity crisis of unprecedented proportions. Therefore, no panic. Patience. There will soon be some distress sales. That's when you can snap up a bargain, even in the Stuttgart area. Especially if you have that much money lying around. Banks have special departments that basically market such distressed properties under the table. Maybe you should get in touch with them.

I would also have liked to build the suitable standard house, but the development plan is extremely restrictive and only angled houses with a shed roof are possible. The houses are so long and narrow that even omitting the angle unfortunately no standard house fits..