My bicycle shed is now also getting a metal roof

Then you don’t have to comply with the BKW limits either, because a BKW also expands the existing system and therefore you can equip your 5 possible modules with a suitable inverter or string inverter and then simply report an extension for your current system.

Isn’t there a deadline (2 years) within which the system expansion must be reported in order to qualify for the same feed-in tariff? Also, a suitable electrician would have to be involved (one authorized by the grid operator – right?)
The system went into operation in September or October 2021.

Deadline, I don’t know anything about that, but an electrician is probably necessary. And, as far as I know, you cannot register a [BKW] next to an existing photovoltaic system on the same meter.

And, as far as I know, you cannot register a BKW in addition to an existing photovoltaic system on the same meter.

But that should be possible. As far as I know, the system sizes are proportionally divided in percentages and the remuneration is calculated accordingly.

Isn't there a deadline (2 years) within which the system expansion must be reported in order to qualify for the same feed-in tariff?

No, that is a different issue. It concerns the tiering of the tariff. If the expansion occurs more than 12 months after the commissioning, the system size is counted anew for the tariff rate. For example, if you already have 9kWp and add another 9kWp, then if the expansion is within less than 12 months, it counts as a single system (with 18kWp) and you receive the tariff rate for <10kWp for 1kWp and the lower tariff rate for >10kWp for 8kWp. If more than 12 months lie between, the new 9kWp are calculated entirely at the tariff rate for <10kWp (each time, of course, according to the tariff rate at the time of expansion, not the old rate).

But that should work. As far as I know, the plant sizes are divided proportionally in percent here and the remuneration is calculated accordingly.

I may have expressed myself incorrectly, I mean that for a BKW, if another plant already exists, the simplified BKW registration is not possible, but it must be reported via an electrician. Regarding the remuneration, I agree with you again.

Photovoltaics complete ☀️
Will be registered normally so that I can partially benefit from the slightly higher feed-in tariff