Photovoltaic experts - Doing something good for our electricity consumption?!

Hello,

we are currently dealing with photovoltaics and are now considering doing something good for our electricity consumption :) Since we have a relatively manageable electricity consumption (about 2500 kWh), only a small system is an option for us. I am thinking about 3 kWp - 3.5 kWp, with the goal of increasing self-consumption as much as possible, possibly in combination with a storage system that we might add later.

But first of all, the idea is to operate the photovoltaic system alone. We would choose an east-west orientation to use the sun for as long as possible. There is practically no shading. We plan with about 30% self-consumption – is that realistic? The rest we would have to feed into the grid.

We do not want to finance the system but pay from our own funds, as otherwise the amortization would practically be pointless.

Question: how high is the tax effort (keyword VAT advance return and annual financial statements)? This topic scares me the most. Is the benefit of the system reasonably positive in relation to that, or does the paperwork take more time than expected? Have you regretted it? How is your system running? Are you satisfied, also with the yields and the feed-in? Or do you have more effort than expected for maintenance, billing, etc.? How big is your system? And is 3-3.5 enough to later add an electric car?

I am very curious about your experience.

Patrick

Whether self-consumption is realistic or not strongly depends, in my opinion, on your "usage profile."

If the laundry is mainly washed and dried on Saturday evening, the electricity for that does not come from the photovoltaic system. If you work during the day and like to cook in the evening, same thing. And so on. We also calculated that ourselves. A return is hardly to be expected despite a very large roof area with exact south orientation. If at all, one should directly install 10 kWp, because then the acquisition costs per kWp decrease, making amortization more tangible.

Buffer storage is currently too expensive to be economically sensible.

Photovoltaic systems can in my opinion be economical if self-consumption is as high as possible. A pure feed-in system is hardly profitable nowadays. Especially not with such small system sizes – the profit is basically in purchasing. 7 kWp and 10 kWp are "magic" sizes, because as Knallkörper already said, the costs per kWp capacity drop significantly when aiming for these sizes. To increase self-consumption, you can buy "smart" solutions, i.e., technology that controls. But that costs money again. Alternatively, you can make sure that large consumers run specifically when a lot of yield from the photovoltaic system is expected, e.g., dryer via timer at 12 noon, definitely not at night. With that, however, I have probably already named one of the biggest consumers that can be reasonably scheduled. Owners of a heat pump have it much easier to increase self-consumption. You might now think to increase self-consumption through storage. But the storage systems are so expensive with simultaneously low lifespan that the calculation definitely does not add up. Of course, you can charge an electric car with photovoltaic power and thereby increase self-consumption. It’s unfortunate if the car is not at home all day and should be charged in the evening with little light. Also, considering the battery capacity of the car, the photovoltaic system should be regarded as rather subordinate. Depending on location and weather, about 3 kWh per day might come from your roof – while your Tesla plugged in wants to charge 90 kWh within 2 hours. I would not expect any return in your scenario. The system is too small and therefore too expensive to purchase, self-consumption rather questionable due to overall very low consumption and no controllable, large consumers present.

We have received an offer for a photovoltaic system of 6.35 kWp, planned 5,183 kWh yield per year with Senec storage and -Cloud). For the photovoltaic system alone, over €10,000 would be due and the same amount for the Senec storage (5.0 kWh). The calculator from the Umweltinstitut München helped a bit! (Umweltinstitut München Solarrechner .xls; google it). We have not decided yet! (possibly photovoltaic system first, storage later!).

€10,000 gross or net? If net, then throw the offer in the bin and get more quotes. Overpriced.
A 5kWh storage is probably oversized for the system size anyway, you will never fully charge it.
The storage is obviously outrageously overpriced, each kWh will easily cost you over 40 cents, it’s never worth it. Prepare it and check in a few years if it might be worth it then.

Thank you Alex! It is the total price including installation (gross), exactly €10,256