Offer for photovoltaic system including storage - Storage yes/no?

I was in the fortunate situation that I can and could do my photovoltaic DIY. I was not willing to pay these moon prices and then not be able to freely choose 99% of the hardware.

I then built a Victron system where the storage is mandatory and backup power is included for free. Here, you also have to consider high and low voltage separately.

Since we are away during the day and only cook, wash, etc. in the evening, the storage is usually at 15% the next morning. The system went into operation at the beginning of July and had about 25 charge cycles in the first two months. I am curious how a whole season will look.

Overall, my 22.88kWp photovoltaic + 19.2kWh storage + masonry house for the technology + climate split cost me about €960/kWp.

I approached the calculations very pragmatically. Electricity installments before photovoltaic €293 and after photovoltaic €50. So €243 saved per month and disregarding the Renewable Energy Act remuneration. The system has paid for itself after 7-8 years.

Woulda, coulda, shoulda.

You first have to get the 50 kWp approved by the grid operator. Nowadays that's not so easy anymore. Unfortunately, the power grids in Germany are outdated.

And if you want to retrofit, you start all over again. Data cables, smart meter, remodeling the meter cabinet, installing storage, and also a new inverter. A fully roof just doesn’t make sense.

That only really pays off with large systems and direct marketing..

No problem at all to get that approved. I wouldn’t even have to remodel my meter cabinet and meter.
My house connection already has 3x175A ;) I would then build a battery park and use everything myself.
It wouldn’t even be about profitability for me.

No problem getting that approved

I'm glad it works for you. Unfortunately, in many parts of Germany it just doesn't work. It always depends on where you live.

Most also do not have space for 50 kWp.

Don't try to make it too complicated. If you're unsure about the storage, just leave it out for now and use an inverter that can run the battery. Currently, battery prices are quite low. That will continue for the next few years. I can tell you from our experience. We have a nearly 10kWp system without storage. In summer, it pushes almost 9kW and we consume about half with all kinds of devices. I'll leave out the e-car for now. So in summer, our storage would be permanently full if we had one. In winter, the system produces about 2-4kW in the sun, depending on the time of day. As soon as a cloud appears, it quickly drops to 1-2kW. With more clouds, it can quickly be just 0.2-0.4 kW. That, of course, doesn't get you anywhere. The battery then gets bored or is empty after 2 hours at the latest. You see, the battery really only has its raison d'être in summer.

There are thus 2 sensible options: 1. A small battery of around 4kWp. That makes you quite self-sufficient in summer, and in winter you save the little surplus that is occasionally produced. 2. You wait a few more years to buy storage until the first car batteries come back. For a few years now, an industry has been emerging that specializes in buying up these batteries and refurbishing them as large storage units for the home market or commercial use. You would have a seasonal battery, filled during the summer and then used in autumn and partly in winter. Currently, you can hardly afford these batteries, but that will improve over time.

You see, the battery actually only has its justification in summer.

Unfortunately, that is the downside of photovoltaic systems in general: when they generate the most, it is needed the least. This applies both daily and yearly. Unfortunately, smoothing this out on a small scale is (still) not economical.

On paper, under ideal conditions such as no snow and so forth, your system should generate about 450kWh in December, realistically probably less due to degradation. That would be 15kWh per day. With a normal electricity consumption of 3,500kWh/year, that amounts to 291kWh per month, while electricity consumption is higher in the winter months. This could just about be covered. For a significant portion from the roof to end up in the battery, neither a heat pump nor a car may be connected. The battery only becomes interesting when the system is really large and the cost of the battery approaches zero, allowing it to be dimensioned significantly larger and to serve as a buffer for more than one night.