Evaluation of photovoltaic system offer with storage

But at most the dirty one. It is likely that people who want to invest money in photovoltaics & storage not only focus on savings but also on clean energy, and therefore would not buy non-green electricity. If you value genuine green electricity without certificate juggling, you’re likely looking at over 40 cents.

Well, here they are again, the feelings about electricity. People would rather set up a big lump of lithium and call that environmental protection... Realistically, the fact is currently that whenever you consume green electricity, someone else cannot consume it and has to use "dirty" electricity instead. Regardless of whether that's through certificates, other "genuineness" promises, or your storage.

Realistically speaking, it is currently the case that whenever you consume green electricity, someone else cannot consume it and has to consume "dirty" electricity instead.

However, if more people demand green electricity and fewer people demand dirty electricity, this supports the energy transition in the long term. That's how the market works. If no one wants the dirty stuff anymore, there is no need to produce as much of it.
It's like all the veggie and vegan products at discount stores. While conservatives are still arguing whether vegan schnitzel can really be called schnitzel because it confuses consumers who have been drinking scouring milk for decades – meanwhile, vegan products are taking up more and more space in discount stores and are displacing conventional products from the assortment. Because they are in demand. People don't care what it's called; they want to buy it.

100% green electricity currently available for at least 24.66 cents. Contracted two weeks ago. Even from the municipal utilities and not from some letterbox energy company.

Not here. I signed a contract at the beginning of September, the cheapest reputable one was Vattenfall at 29,x with a base fee of €12.99. Others were a little cheaper, but usually with higher base fees. So 30 cents as a basis is already OK. It is also labeled as green electricity. Whether it’s real or not doesn’t matter to me here. Over the year, I definitely feed significantly more genuine green electricity into the grid than I take from it.

Good evening! Thank you very much for your truly helpful comments as well as the example calculations. If you also consider here that with current interest rates you will pay around €1000 in interest over the next 10 years, the calculation worsens further. Since we are therefore at an even higher payback period than the calculated 12-19 years and, contrary to some opinions, I have little emotional attachment to the purchase, I will, based on the current situation, decide against a storage system. Additionally, I have roughly compiled the consumers for the evening and night, here I am probably not the right user and "live" too much in the light ;-) Even if the storage lasts 5 years longer than the payback period, that would only be a theoretical gain of €1650 with 150 cycles, so no thousand euros when you also consider the interest. For me, that is not a worthwhile investment because if it causes problems after 11-12 years, I would even put a similar amount on top of that. The question now is: would the photovoltaic system with the 11.9 kWp without storage still be the right one or should I adjust the capacity in some way, either up or down? Best regards

Always as much as the roof allows. Up to 25° pitch, even the north side can be sensible.

Always as much as the roof allows. Up to 25° pitch, even the north side can make sense.

Hmm ok, is that really the case? It feels like it’s less profitable if I produce too much and feed in for little money? The modules also cost money again...
The roof pitch is 30°. The roof surfaces face SE and NW