ᐅ Photovoltaic Systems: Advantages, Disadvantages, Experiences, and Is It Worthwhile?

Thanks first of all for the clarification.
I had no idea that the batteries are so expensive. What capacity do you need for a single-family home with 150sqm (1600 sq ft) that makes these things so costly? Online, I find lithium batteries ranging from... to... – at first glance, they don’t seem much more expensive compared to the photovoltaic system. Unfortunately, we can’t contribute any own labor for the photovoltaic installation. So, a photovoltaic system with KFW funding: possible – battery: better to avoid?
@Lumpi_LE Actually, my main concern is self-consumption; I wasn’t aware of taxes on feed-in so far – is feeding electricity into the grid mandatory?

Zaba12 schrieb:
You have to say, the hotter it gets, the less efficient the system becomes. I have read from many that the best month in 2018 was May. All other months, especially the weeks with temperatures around 30°C (86°F), performed worse on average.

My July was even better, although the chart only shows the electricity sold... I always read from the bidirectional meter...

Photovoltaics in grid-tied systems are definitely attractive since the material cost is basically zero. However, climbing around on the roof felt a bit too risky for me... If you’re going with a grid-tied system, why did you build it so "small"? What’s the capacity? About 7 kWp?
@Bau_Bambi You don’t have to feed electricity into the grid, but then it becomes a very expensive hobby. Taxes on feed-in are currently not relevant—what do you mean by that?

For me, being taxed means that I have to pay extra money on the electricity I generate myself, even though I could use it for my own consumption “for free” without having to buy any from the supplier. So I would be taxed on my self-generated electricity, meaning paying extra money, and then pay twice because I still have to buy some additional electricity.

I probably don’t know enough about this. Maybe it makes sense to discuss it again with the architect and energy consultant here.

Well, they usually have little knowledge about that.
With standard taxation, it's correct that you have to pay 19% VAT on your self-consumed electricity. However, there is also the small business regulation, where you do not have to pay this.

Lumpi_LE schrieb:
Solar panels in low-voltage DC are definitely cool since the material itself basically costs nothing. However, climbing around on the roof was a bit too risky for me... If you’re using low-voltage DC, why did you build it so “small”? What is it, about 7 kWp?
@Bau_Bambi You don’t have to feed electricity back into the grid, but then it becomes a very expensive hobby. Taxes on feed-in aren’t really relevant now, or what do you mean?

6.24 kWp
A former schoolmate of mine runs a company that designed the system for me. I bought the materials there.
He said that you don’t necessarily need more than that; for the price-to-performance ratio, this size is absolutely sufficient... you can always go bigger, but the budget has to allow for it.