Are you really all spending that much on a photovoltaic system??? For 15k plus euros, I could consume a lot of electricity in summer (don’t know which) before it pays off. Wow! And then the stuff still has to be produced, transported etc. Sustainability is something else. Sustainable is what is NOT needed. Think about that. But sure, nice to add the EQS and then the conscience is clear
It always depends on consumption. Double home office + heat pump. For 15k I can’t buy electricity for that many years. We currently have a monthly installment of €185, without the heat pump yet. So the trend is rising. With your 15k you’d get about 6.75 years, with a heat pump even less time.
I had calculated our last system very pessimistically and thought it would only pay off after 15 years. In practice, very different values came out than we expected. We broke the €1000 savings mark in just over a year, purely in electricity costs that we otherwise would have had to buy. We had estimated about 35% self-consumption, but with heat pump, air conditioning, and home office, we mostly ended up at 50-60%. That pays off quickly.
The system back then was only 4.55 kWp and we actually paid the general contractor €9200 gross, which was too expensive (for the standards back then). Nevertheless, the performance convinced us so much—not least in spring and autumn, where good synergies with the heat pump appeared—that we are planning a larger system for the new house.
The only thing I’m still not convinced about is the storage technologies. I still find the storage too expensive for the projected lifespan and the experiences with battery wear and tear that you have, as well as the warranty. With photovoltaics, maybe an inverter breaks after 10 years, but you can replace that reasonably cheaply. Usually nothing happens to the modules; they last forever.
By the way, my parents participated in the “1000 Roofs Program” back in the day, if anyone still remembers. There was definitely a feed-in tariff of 99 pfennigs per kWh. My mother received that until recently (now about 50 cents). Then unfortunately the 20 years expired, and the grid operator unfortunately cut it off. :D It was, of course, still a small system from those times—but it still runs today (after more than 20 years) with the first inverter. Nothing ever went wrong with it.