ᐅ Should You Install a Photovoltaic Battery Storage System or Not?

Just a thought to everyone, I think it’s helpful to mention whether the € amounts per kWp are gross or net. Of course, the VAT is reclaimed. Still, I can imagine that some state it with VAT included and others without. This can lead to misunderstandings or make comparisons difficult.

RotorMotor schrieb:

Although we’re moving away from the main topic of storage, most of it has actually already been covered. It’s neither economically nor environmentally a very good idea.

Regarding the north side: as mentioned, you really have to calculate it precisely. My numbers were just an example. Looking around on the internet and various forums, I think they’re not unreasonable or incorrect. Maybe your figures are net values?

However, I never said that the north side is cheaper simply because it faces north, but rather due to “quantity discounts through synergy effects.” I don’t find a 30% discount unreasonable considering how cheap photovoltaic modules are to purchase. Additionally, the 60–70% capping limit on northern installations could benefit the south side as well.

From an environmental perspective, photovoltaics pay off after about 5 years. On the north side, this takes about 7 years, which I still find acceptable!

We will probably have a 45-degree roof, which corresponds to a loss of over 50% on the north side; in that case, you can realistically only do self-installation.

1. The difference between a purely south-facing system and a combined north/south system results in an additional cost for the northern expansion, thus a separate price per kWp for the north. The inverter may only need to be sized larger, grounding requires only one cable, additional wiring effort is reduced, quantity discounts on modules, etc.

2. The capping limit is avoided.

3. Energy yield from the north (or east/west), while low, is generated when almost none comes from the south, so it is mostly self-consumed (base load)! Especially in the morning and evening. This actually increases the return on not purchased kWh (I’m not talking about the 7–8 cent feed-in tariff, which is acceptable too).

4. The system does not just disappear after 20 years!

Notes: The autonomy rate shown in offers is usually nonsense (from an economic perspective only). Every single return calculation made by a solar installer was dismantled within minutes and proven to be incorrectly calculated.

Nevertheless, nearly every photovoltaic system (without storage) pays for itself. Forget the 20-year “lifespan” (see above) ... it would have to be unbelievably expensive not to.

Outside of purely economic considerations, of course, some people install photovoltaics for completely different reasons ... :p

And folks, please don’t keep mixing up kWp, kWh, and kW ... 😉

Zaba12 schrieb:

Uh, sorry, but why should the price be 1300€/kWp? Back in 2018, I already received an offer of 1130€/kWp including installation. My solar installer would have thought I was crazy if I had said that, just because a north-facing system yields 35% less, I now expect a price of 735€/kWp for the north installation, just because I’m doubling from 8.68 kWp to 17.36 kWp. But I don’t want to sound like a smart ass. If someone really pays 35% less for a north-facing system, then fair enough.

At least here in NRW, you can be glad if any company even agrees to provide a quote. With the first quotes I received, I thought they were trying to fool me!
At the start of my photovoltaic search, I also had a different mindset (my mental limit was 1000€ net per kWp for purely photovoltaic without battery and wallbox). If I were more skilled and didn’t earn too much money in too little time by typing, I would seriously consider doing the installation myself. It’s not rocket science. You just need an electrician to make the electrical connections.
I’m happy to share my photovoltaic offer here once the work is completed. (But since we’re building a KfW40+ standard house, it’s probably not very relevant to most, as it includes a battery storage system and two wallboxes.)

superzapp schrieb:

At the beginning of my photovoltaic search, I thought differently (my mental limit was 1,000€ net per kWp for pure photovoltaic without battery and charging station).

Currently, for a 10 kWp system, you will be around 1,150€ net. The (controllable) charging station just cost 200€ including installation (in NRW thanks to subsidies). If battery storage were properly subsidized here as well, I would have added one too.

superzapp schrieb:

1. The difference between a pure "south-facing system" and a combined north/south system results in an additional cost for the north expansion and therefore a separate kWp price for the north. The inverter may only need to be sized larger, grounding requires just one cable, overall wiring effort is lower, and there is a volume discount on modules, etc.

2. The capping limit is avoided.

3. Yield from the north (or east/west), even if small, is generated when the south produces almost nothing, so it is mostly self-consumed (base load)! Especially in the morning and evening. This is where the real return comes from in terms of kWh not purchased (I’m not talking about the 7–8 cent feed-in tariff, which is acceptable).

4. The system does not just disappear after 20 years!

Notes: The self-sufficiency rate shown on quotes is usually nonsense (only economically considered). Every single profitability calculation from a solar installer was analyzed within minutes and clearly proven to be incorrectly calculated.

Still, nearly every photovoltaic system (without storage) pays for itself, forget the 20-year “lifespan” (see above) ….. It would have to be unrealistically expensive not to.

Beyond purely economic considerations, of course, some people install photovoltaics on their roofs for completely different reasons ... :p

And folks, please stop mixing up kWp, kWh, kW all the time ... 😉

Point 3 must have been suggested to you. In practice, this applies roughly from the end of April to the end of September (and the yield decreases over this period) for less than 2 hours, basically only when my south side no longer covers the base load at 7:30 pm.

Outside of these months, the sun doesn’t even reach the north side to produce any significant yield, as by then the sun has already set.

Take a look at the website Sonnenverlauf.de and try playing around with the months a bit.

Since electricity somehow keeps getting cheaper with regular supplier changes, a photovoltaic system only pays off after well over 15 years. This repeatedly leads me to discard the idea. The environmental aspect and long lifespan aside.