Photovoltaic system offer for our single-family house

There is a way to go from 25 to 20 [spacing].

Oh, kind of "abstandern" :D

Especially in winter, the low sun does not hit the north modules.

Who’s talking about sun ;)
Especially in winter, the sun often does not shine.
Every watt is precious there, and north doubles the yield!

With the effort and the shading you are, of course, right. But in PVSOL, I think you can also use a raised structure. I would always get two quotes. Once only south, once south and north. Put the € difference in relation to the north yield. Then you know where you stand. Autonomy can be left out, it is the buffer.

The electricity price on the exchange has increased by 270 percent as of today compared to last year's price. This price increase is not yet factored into the current electricity prices.

Electricity for the December contract costs 52.4 cents per kWh today. Intense, I would say.
We are talking about net prices without VAT, grid fees, and all the other nonsense. We would probably be talking about gross prices around 1 euro / kWh.

The electricity price on the exchange has increased by 270 percent as of today compared to last year's price. This price increase is not even priced into the current electricity prices yet.

Electricity costs 52.4 cents per kWh today for the December contract. I would say that's intense.
We are talking about net prices without VAT, grid fees, and all that other nonsense. So we are probably talking about gross prices close to 1 euro/kWh.

But this will not remain the same, just like with gas.
If it stays like this, there will be no industry left in our country in 2-3 years, because they often pay these exchange prices directly.
Energy-intensive industries no longer pay off if energy costs 10 times as much as in 2019.

Therefore, I would be cautious about calculating with the sky-high prices from 2022 when buying photovoltaic systems or heat pumps at sky-high prices from 2022.
However, I can understand that craftsmen charge these prices. Usually, the photovoltaic system ordered today will be installed sometime in early/mid 2023. How the price will develop until then is unforeseeable.

My company has already raised prices twice in 2022 and there will be another price adjustment in October. Anyone who lets themselves be pressed by customers today risks having to bring money in mid-2023 to install the photovoltaic system on the roof.
And why should anyone allow themselves to be pressured? People are lining up; the rush for photovoltaic and heat pumps is gigantic, there is almost panic involved.

missing. The consumption may actually be calculated optimistically, BUT the electricity price of €0.35 also... I hardly believe that in 10 years people will still pay €0.35.

It's always somewhat a bet on the future. Clearly, the calculation with only South makes the model more lucrative, but I have also read so often here in the forum that you should fully utilize the North side as well, especially if you have an air-water heat pump.

Everything is rather optimistic. Taxes on feed-in are also missing.

Calculate for South only.

I have to dig up this thread again now. You say the taxes on the feed-in are still missing. Isn't it the case that the feed-in tariff is net, and the grid operator charges VAT on these 7.62 cents (in my case this is the amount because 21 kWp and thus not completely 8.2 ct) and pays it out to me?

I believe you are mixing up a few things.

Value added tax applies to self-consumption (if you have deducted it beforehand in the system).
Income tax applies to feed-in (if the income is "large enough").

With my previous post, I meant the income tax, which often significantly reduces the return.