Economics of Photovoltaics - My Findings - Is Something Missing?

Thank you for the information. I will take a look at it right away.

Oh yes: And 70% soft.

At least if it can be realized cheaply (S0 counter), otherwise it’s not worth it. And of course only if the energy consumption could also be over 30%, otherwise it’s pointless. Oh yes, with East/West systems it also makes no sense. Actually a pretty annoying topic

Correct, but then you need 2 S0 meters. One for the surplus feed-in 70% soft and one for the heat pump consumption.

And despite 70% soft, you still burn something on a few days a year... 5.4kWp results in 3.78 kWp at the connection point.

So now for beginners. I only need a bidirectional meter, nothing more. The smart meter is connected to the photovoltaic system.

And a regular household electricity tariff. Why did the solar installer babble something about cascade or series connections?

It depends on exactly what you want and what you can get locally at your place.

Basically, a two-way meter is enough. That gives you 70% hard and the heat pump runs on household electricity.

With the right inverter and an S0 meter, you get 70% soft. And if you take a second S0 meter, you can even measure the heat pump electricity. For example, this is needed to determine the annual performance factor.

With a cascade, you can probably use the heat pump tariff additionally. Whether this is worth it, you have to assess yourself. For us, it was not worth it from the beginning (initially had 2 meters). When the photovoltaic system came, it was rewired and the second meter was removed. It even had the nice side effect that the blackout period was eliminated.