Economics of Photovoltaics - My Findings - Is Something Missing?

It is said 1-2% loss for hard.

The soft regulation is also cheaper to get, with WR from Fronius you only need one S0 meter for 60€.
Many do SHM anyway not just because of the soft regulation, but because of the comfort functions it brings.

No idea what a Sunny Home Manager is and what it does and what else it (might) bring.... for me, the inverter itself handles it, only an S0 meter was necessary, which I would have wanted there anyway.

So additional costs = 0

Sometimes less is really more, just unnecessarily wasting energy is stupid. Almost as bad as plastic waste.

The whole calculation fails with the decreasing performance of the modules, which is not considered by you.

Thank you for the remark! I should include the factor of degradation in the calculation.

What if the yield corresponds to only 50% after 20 years?
Is the decrease in performance linear or exponential?

However, today's modules have a performance guarantee of 80% after 20 years. So it seems reasonable to me to deduct a flat 10% from the yield. Then I am too low at the beginning of the 20 years, too high at the end.

How many hours have you actually invested by now? Isn't the photovoltaic system slowly becoming unprofitable? You have probably already used up the first year of feed-in tariff...

Just do it.

No idea what a Sunny Home Manager is and what it does and what else it (might) offer.... for me, the inverter itself does that, only an S0 meter was necessary, which I would have wanted to have there anyway.

Yes, that is an advantage of Fronius that only an S0 meter costing €60 is necessary. With SMA, you need a Sunny Home Manager for €590.

I have factored in a depreciation of 20% over 20 years. The return decreases from 8.7% to 7.9%, the amortization increases from 11.5 to 12.7 years.