Lower Saxony subsidizes photovoltaic storage

: Why shouldn't 10 kWP fit on your roof? The roof doesn't look that small at all.

The house width is 9.5x9.5m with a 60cm roof overhang.
The distance from eaves edge to ridge height is 2.5m with a 28° roof pitch.

I don't know if you can derive anything from that about what might fit on such a roof.

You would have to increase to at least 8.55 kWP, otherwise there is no funding.

The system can certainly be expanded by any other solar installer. Why shouldn't it work? Find a good solar installer and check with them what your current inverter could handle. Buying a new inverter for just 4 additional kW doesn't sound economical to me.

We have a Kostal Plenticore Plus 4.2 kW, I believe it can't handle more than our current system capacity (?).
Why would I have to go up to 8.55 for the funding? I thought a storage system would also be funded if you add it to a system with more than 4 kWp that you already have?
Edit: I read the excerpt again properly, now I understand why. Ok, then I would have to see if 8.55 would fit.

Did you also install panels on your north side, etc.?
Or how is the system divided on your property?

Are you asking me? We have a hipped roof, where a triangular area (see avatar) faces south with a slight east slope. Six modules are installed there. On the west side (which is logically slightly rotated towards the south) there are 18 modules. On the east side, 18 modules would have also fit, but the area was totally shaded because there were large oaks on that side stood (they were cut down the following year :rolleyes:). The north side, with only 6 possible modules, was not worthwhile in terms of yield.
Now that the oaks have been cut down, I would like to install panels on the east side as well. For that, however, I would need a new inverter again...

how large is your total roof area? Or rather, the eave length?

I can't tell you exactly, but here is a picture of the installation:

I don't think I will exceed 10KWp anyway... That’s why this funding will be off the table for me... 5 KWp would be enough for me and a storage unit. And then a wallbox. Combining all that with the Bafa would be great!

Enough? Or no more space on the roof? The ratio of generator to battery storage should be about 2:1. So only about 2.5KWh battery storage for 5KWp. But then it empties faster than you can blink. Just my humble opinion: put on as much as reasonably fits. Start small with the battery (modular) and possibly upgrade to a useful size if there is appropriate funding or prices fall.