Photovoltaic system offer for our single-family house

Do you have to? I really can’t fully assess the current situation, which also varies regionally. I found my system, ordered 2 years ago per kWp, already "too expensive." But a simple gable roof with a relatively large system only has "one-time costs." My opinion: outrageous. But no matter when the system pays off, I’d probably do it anyway (I once heard something about serious forecasts predicting 50-55 cents per kWh). And then this photovoltaic system, if not already ecological, also looks different economically.

Actually, I would say I’m waiting a bit longer – but since this is about a new build, unfortunately the scaffolding etc. is currently there as well. That means now would be the ideal time :-) I’ll wait for the other offer and then give you feedback.

I am always a fan of filling the roof completely, but at that price, I can hardly imagine that [Nord] is worth it. And then with this elaborate mounting system, which might also cast shadows on the modules underneath.

Actually, I would say I’ll wait a bit longer – but since this is about a new build, unfortunately the scaffolding etc. is currently still there. That means now would be the ideal time :) I’ll wait for the other offer and then get back to you.

Ask . He has invested in photovoltaic modules and still has quite a bit in stock. He might be able to offer better prices.

I have now done some more detailed calculations. However, even with rather pessimistic assumptions, I cannot come up with any scenario in which I would make a loss with the system. Feel free to correct me if any of the assumptions are nonsense...

Let's say the 20.5 kWp system generates 18,000 kWh per year. I can use 20% of that myself (currently air-to-water heat pump, maybe later an electric car). The grid electricity price is €0.35 and the feed-in tariff is €0.0765 ((8.2 cents + 7.1 cents) / 2).

Calculation for 20 years:

Saved electricity costs per year: 18,000 kWh * 0.2 * €0.35 --> €1260
Feed-in tariff per year: 18,000 kWh * 0.8 * 0.0765 --> €1102

This yields, rounded, €47,000 income over 20 years.

Against that are expenses of €30,000 (net) and about 20 x €200 operating costs / insurance etc., so €4,000 = €34,000 expenses.

€47,000 - €34,000 = €13,000 return.

Am I calculating something wrong?

Even if the output were only 15,000 kWh, there would still be a profit (€5,000 surplus)...

With 20.5 kWp on north and south, you should probably expect rather 80 - 85 % yield: 16,400 kWh

How much household electricity consumption do you estimate in total? 3000 kWh? 4000 kWh? Without storage, you will probably be able to consume max 1,500 / 2,000 kWh yourself. Pessimistically 1,500

It would be the same with a heat pump… you need most energy from November to March. At that time, photovoltaic electricity is rather low. So maybe a total of 1,000 kWh

2,500 x 0.35 = 875 euros 13,900 x 0.0765 = 1,064 euros Total 1,939 x 20 = 38,780 euros

In 20 years you can plan for a new inverter on each side. So 2 x 2,000 euros

With 200 euros operating costs, you end up at break-even

But don’t forget the financing costs…

However, every additional self-consumed kWh leads to an improvement in the return. Also, prices will probably continue to rise.

So: Install the system

Everything is rather optimistic.
Taxes on feed-in are also missing.

Just calculate for the South.