Waiving feed-in tariff, always feasible? Storage price?

Hello dear people,
we are planning a small 5.7kwhp system. We are still undecided whether to include storage or not. Through our BT, we have been offered storage of 5.12 Kw for just under €10,000. That seems very expensive to me. Can it be added later at a lower cost? Including installation?
But my main question is; for an assumed 5,000 KWH per year of electricity, minus own consumption (depending on whether with or without storage), there isn’t much left to sell to the grid operator. Plus the "effort" with the tax office... Despite simplifications for smaller systems, as far as I know you still have to deal with the VAT declaration... We would gladly do without the few euros completely if that means that as far as the tax office is concerned, we are completely "out." Is that possible?
Thank you very much for your help!

In advance: So you want to set up an off-grid system for your own consumption. This only makes sense if the system is small enough (balcony power plant) or has a suitably dimensioned storage. Everything else is pointless because without storage you would lose 60-70% of the electricity.

Regarding the "effort" with the tax office...

200€ annual income – with an effort of about 60 seconds per quarter in the first year (and possibly the second year) and afterwards only once a year?
A photovoltaic system does not require effort. That’s a rumor and you can do it without a tax advisor.

Oh yes, with an off-grid system you pay the gross price anyway, since you save yourself all the hassle with the tax office. So for your system costing €10,000, that’s already €2,000 "entry fee." And then another similar amount for the storage.

Thank you, but my question "whether" I can do without it... was not answered. And no... for €200 a year given as a gift, I do not want to fill out anything for the tax office. However, I think we should buy "with" storage... so that the scope of my gift remains limited... the question still is: Am I allowed to give away my electricity so that I legally have NOTHING to do with the tax office?

"Inselanlage" has nothing to do with everything written here. Please forget that immediately.

Regarding the original question: If you don't want to have anything to do with the tax office (after an initial application for hobby status), then build a maximum of 10 kWp (possibly soon 30, you still have to wait briefly to see if that goes through) and forego reclaiming the VAT. You can still feed your electricity into the grid and get reimbursed for it. I would definitely recommend that - even with small systems, it is often more than you think.

The storage is about 7 times too expensive to be economical. I would therefore omit it.

In general: The planned 5.7 kWp is quite small. The larger the systems become, the more economical they are and the more you can benefit from them in the future. For e-mobility and heat pumps, almost any system is too small. It would therefore be sensible to first find out if additional roofs are available. That includes the north roof, if it is not steeper than 25°.

And no... for 200€ a year as a gift, I don't want to fill out anything for the tax office.

How long do you usually work for 4000 tax-free euros?

What are the 5.7 kWp on the roof supposed to cost when the storage already costs €10,000?
The storage for that money is absolutely nonsensical and thrown away money. It will never pay off.

If you waive the feed-in tariff, you should consider whether the entire system is worthwhile at all.
Depending on what the 5.7 kWp cost, you will never recoup the costs just through self-consumption.
Your main consumption is in winter, and you will never be able to fully charge the storage to get through the night.

I also don’t understand what the problem is? You can also feed in without having to submit VAT. It's called the [Kleinunternehmerregelung]. However, then you will not get the VAT on the purchase of the system refunded either.

What is your problem with the 2 minutes of work per year for VAT (exactly 2 figures have to be entered)?
In the end, you are giving away several thousand euros because of that.