Photovoltaic system – is it worth it?

I agree with the first sentence in the case of Germany.
The storage costs of >30ct/kWh were correct about 2 years ago. That's when I bought my storage system, and it has about 31ct/kWh.
Nowadays you can implement a storage system for under 25ct/kWh. With appropriate demand and design, I have already seen offers for under 20ct/kWh. In 5-7 years, a storage system will almost certainly be cheaper than feed-in and repurchase without the Renewable Energy Act.

Regards, Nika

Really? Do you have a calculation example for that?

I just quickly looked for a storage system in an online shop. NeeoBASIX 6.5 for €6790. Nominal capacity 6.5 kWh, usable capacity 5.5 kWh. Expected cycles 5000. That means 27,500 kWh go in and out, without considering storage losses or standby power (winter time!). €6790 acquisition cost divided by 27,500 kWh is 24.7 cents per kWh purely for the acquisition cost of the storage system. Without labor, without accessories. Plus ~4 cents VAT on self-consumption.

Photovoltaic power generation about 5 cents/kWh, plus storage price 25 cents/kWh, VAT 4 cents/kWh. That makes at least 34 cents/kWh for a self-generated, temporarily stored and then self-consumed kWh of electricity. That this is nonsense is obvious, as ordinary grid supply would already be significantly (!) cheaper.

My suggestion:
Photovoltaic power generation about 5 cents/kWh, minus feed-in tariff 12 cents/kWh. That makes 7 cents profit. Nighttime repurchase from the electricity supplier here 23 cents, which effectively means 16 cents for the kWh of electricity in the oh-so-expensive electricity storage "power grid". That is cheaper than any electricity tariff a private customer can get.
Better is, of course, only the direct self-consumption, which comes to about 9 cents/kWh due to generation costs plus VAT.

In 5-7 years, a storage system will almost certainly be cheaper than feed-in and repurchase without the Renewable Energy Act.

That may be true, but it’s by no means an argument to buy a storage system now, especially when no one will guarantee its capacity after 10 years. Even though 5000 cycles are already not bad and definite progress can be seen here.

As soon as the Renewable Energy Act expires, storage will be the only option if you don’t want to give the generated electricity away to the supplier. At least according to the current situation. If politics are still asleep there, the systems will be scrapped just like what’s happening now with the wind turbines. Great energy transition.

: Your question was whether photovoltaics are worthwhile. Hardly anyone can give you good advice for your personal situation. The conditions can vary greatly. Look at the electricity price trends in your region over the last 20 years. Then get a quote for the simplest possible system. Estimate your future electricity demand, try to calculate an average electricity price for the next 20 years (cautiously), and then do the math yourself.

Really? Do you have a calculation example?

I just quickly looked for a storage system in an online shop. NeeoBASIX 6.5 for €6790. Nominal capacity 6.5 kWh, usable capacity 5.5 kWh. Expected cycles 5000. That means 27,500 kWh go in and out, without considering storage losses or standby power (winter time!). €6790 purchase cost divided by 27,500 kWh is 24.7 cents per kWh just for the purchase price of the storage. Without labor, without accessories. Plus ~4 cents VAT on self-consumption.

PYLONTECH LiFePO4 storage 48V - 7.2 kWh for €3500. With that, you can almost halve your calculation, I would say.

But these are only the pure memory cells

The problem is that not everyone has an unlimited credit line. However, the purchase has to be paid immediately. Especially in the renovation of old buildings, there are often better alternative investments in insulation, heating technology, etc., which pay off much faster and generate greater benefits for the environment. Especially the storage technology with lithium is an ecological disaster in production.