Photovoltaic system that pays for itself monthly and amortizes

Storage only with subsidy. That's easily 6-10k € that you'll never get back.

I think, but this is just a gut feeling, that it is slowly developing from a hobby (regarding storage) to a useful and cost-neutral item. But of course, only under certain conditions. For existing systems, a hybrid inverter must be present and for new systems, every kind of subsidy must be taken advantage of....

Because storage is also not as expensive as it was, for example, 3 years ago. I’m getting the BYD high-voltage storage installed at 6.4 kW. With activation (500€) of the hybrid inverter, it’s 5,700€ without subsidy including installation. Online, this thing costs 4k€. In terms of specifications and especially efficiency, this unit is currently supposed to be the best on the market. Whether that’s really the case? No idea, but after some research it at least sounds that way.

For 5,700€ I currently get 16,300 kWh, so from my point of view it’s definitely worth considering.

What is the current acquisition cost per m² of a photovoltaic system including installation and everything involved? And how much electricity does it generate when mounted on a south/east hipped roof with a 28° roof pitch?

I have absolutely no idea about the amounts involved. What such a system costs and how much electricity it produces.

A battery would probably need to be installed with us... I also don't know what something like that costs...

For photovoltaics, costs are not referenced per m² but per kWp, and one should be at a maximum of 1200 net for a system around 10 kWp. How much electricity the system generates can be calculated, for example with pvgis. Roughly in Germany, it is about 1000 kWh/kWp per year.

A battery is not worthwhile but only serves as a toy.

You can take out a loan, it pays for itself, but you don't get that much out of it, meaning a longer amortization period.

For €5700 I currently get 16,300 kWh, so from my point of view it’s definitely worth considering.

Yes, but you must not forget the lost feed-in tariff.
I evaluated with Excel what I could have used myself this year with a 6 kWh battery. That’s almost 1000 kWh savings (in terms of self-consumption), but on the other hand there are about 200 kWh due to storage/charging losses. I get paid a good 11 cents and pay 26 cents per kWh. Assuming 30 cents, I therefore save 19 cents/kWh from the battery. Ergo:
(1000 kWh - 200 kWh) * €0.19 = €152/year.
The battery costs me, since I need additional stuff for SE, currently about €8000. So it would have amortized after 53 years...

yes, but you must not forget the lost feed-in tariff.
I analyzed with Excel what I could have actually used myself this year with 6000 kWh. That is nearly 1000 kWh savings (in consumption), but on the other hand there are about 200 kWh due to storage/charging losses. I get paid a good 11 cents and pay 26 cents per kWh. If I assume 30 cents, I save 19 cents/kWh from the storage. Ergo:
(1000kWh-200kWh)*0.19€ = 152€/year.
The battery costs me, since I still need other stuff for SE, currently about €8000. So it would have paid off after 53 years...

Well I am at €5700 all inclusive. Only makes it conditionally better

Did you always calculate with one full charge/discharge per day from March to September? All other months are anyway semi-interesting.

I know what you want to tell me, but I don’t know how you come to these numbers? (1000kWh-200kWh)*0.19€ = €152/year.

- How much storage loss/efficiency loss are the 200kWh in %? I calculate about 5% efficiency loss due to the high-voltage system.
- How do you get the 1000 kWh?
- I think I get something around 10.8 cents and pay 30 cents/kWh

All those who come in 2020 already get 9,xx cents.

I am more around 200 days of loading/unloading at 6.4 kWh minus 5% efficiency losses due to the high-voltage battery. You can make everything look good or bad with numbers. After 15 years, you are still several hundred euros in the negative.

I have left out the taxation and price increase. In return, you have fewer expenses for the purchased electricity over the years.

The lifespan of a system is often stated as 20-25 years. Is that really the case? Do individual cells or modules fail, or will a complete replacement be necessary later on?