Install photovoltaic power storage yes or no?

You do not consume most electricity at the time when the photovoltaic system produces the most electricity, but mainly during the off-peak hours (6-9 and 16-22 o’clock).
The bigger the system is, the more electricity you consequently generate during these off-peak hours. Ergo, you can then use your own electricity at this time.
With the current system costs of about 1,000 euros per kWp, it also pays off even with 7 cents feed-in tariff (return on equity about 2.5-3%).
The saved self-consumption is basically a bonus and accordingly increases the return.

That’s why you should cover as many directions as possible with photovoltaics! Usually, up to about 25° south of north, the north side also pays off (depending on €/kWp acquisition costs, calculate yourself, don’t trust the solar installers!).

therefore try to cover as many directions as possible with photovoltaics! Usually, the north side is also worthwhile up to about 25° DN (depending on €/KWp acquisition costs, calculate yourself, don’t trust the solar installers!)

That the north side is profitable is pure “propaganda” from the energy transition lobby, just like claiming that shaded photovoltaic systems are productive. If you calculate the yield of a pure north side in PVGiS, you think twice about spending as much money on the north as on the south.

From my point of view, there is only one single economically sensible reason to cover the north side, and that is because you are trained and capable of installing the entire system yourself.

I myself considered covering the north, but reason prevailed. €9,000 for the north that delivers 1/3 less than the south in summer, and then in autumn, winter & spring there is little to nothing. Never…

...I just checked again, in the north there is exactly 35% less yield over the year than in the south.

The fact that the north side is profitable is pure “propaganda” from the energy transition lobby, just like claiming that shaded photovoltaic systems are productive. If you calculate the yield of a pure north side in PVGiS, you think twice about spending as much money on the north as on the south.

From my point of view, there is only one economically sensible reason to equip the north side, and that is if you yourself are trained and capable of installing the entire system.

I also considered equipping the north side myself, but reason prevailed. €9k for the north, which delivers 1/3 less than the south in summer, and then in autumn, winter & spring hardly anything or nothing at all comes down. Never...

I don’t quite understand the 1/3 summer/autumn and winter statement.
Just take the total yield for one year.

If the total yield (kWh per installed kWp) is 1/3 lower, you just have to keep calculating that the north side may only cost 2/3 for the same profitability.
This often works. For example, with a 10 kWp system the kWp costs €1300 and with 20 kWp only €1000.
Due to “volume discount,” i.e. combination of cables, travel, scaffolding, etc.

As said, it depends on the costs per kWp and the actual roof pitch and orientation.

I don’t quite understand the 1/3 summer/ autumn and winter statement. Just take the total yield for one year. If the total yield (kWh per installed kWp) is 1/3 lower, you just have to calculate further that the north side may only cost 2/3 for the same profitability. Often this works. So that in a 10 kWp system the kWp costs 1300€ and for 20 kWp only 1000€. Through “volume discount”, i.e. combination of cables, travel, scaffolding, etc. As said, it depends on the costs per kWp and the actual roof pitch and orientation.

Uh sorry, but why should the kWp cost 1300€? I already got an offer with installation for 1130€/kWp in 2018. My solar installer would have given me a hard time if I said that now, just because the north brings 35% less yield, I expect a price of 735€/kWp for the north installation only because I’m taking 17.36 kWp instead of 8.68 kWp. But I don’t want to be smart. If someone truly pays 35% less for a north installation, then it can be done.

We are indeed straying quite far from the topic of storage, but most of that has actually already been said. Economically and especially environmentally, not a really good idea.

Regarding the north side: As I said, you have to calculate that concretely. My numbers were just an example. If you look around on the internet and in some other forums, I don't think they are bad/wrong. Maybe your numbers are net?

However, I never said that the north is cheaper because it is in the north, but simply as a "bulk discount through synergy effects." I don't consider a 30% discount to be unreasonable when you look at how cheap the photovoltaic modules are to purchase. Additionally, one could also factor in the effect that the 60/70% cap limit on north occupancy brings advantages for the south side.

For the environment, the rule is that photovoltaics have paid off environmentally after 5 years. On the north side, then after about 7. I still think that's good!

We will probably get a 45-degree roof, which corresponds to a disadvantage of over 50% on the north, but then you can really only install it yourself at most.