Photovoltaic system: Advantages and disadvantages, experiences, worthwhile?

It is almost the only retrofit option on new buildings and therefore not attractive at the beginning. Investing in something that only pays off after more than 10 years is at least brave.

I view photovoltaics very critically.

To make it easily retrofittable, you should already consider suitable cable ducts from the roof to the meter cupboard and a sufficiently large meter cupboard during construction.

As an engineer, you surely know that good things take time and not everything pays off within a quarter. The state guarantees you income over 20 years, possible losses are well manageable or insurable. As I said, it won't get much better.

What do you see as critical about photovoltaics?

I see it similarly to the others. Photovoltaics are always worthwhile and offer a good return with low risk, as you are guaranteed to receive money for your produced electricity for 20 years. During the construction of our house, we had a conduit laid from the attic to the utility room. We would have liked to have it installed immediately as well, but the leeway was exhausted at that time. The (rolling) scaffold cost us an additional 700,-€. In return, our satellite system was relocated from the west to the east roof at no cost.

Honest question to you all ... is it really still worth it compared to 10 years ago? What about the block that the network operator imposes on you and throttles you or the feed-in? In winter, there is often a lot of snow on it, so nothing goes in here either.

Without a battery, it is already worthwhile, especially with a heat pump, but only after 10-15 years. With a battery, you can forget it, as the payback period is over 20 years and who knows if the technology will last that long.

Photovoltaics are a nice thing, but we couldn't afford it back then. For me, it is and remains a luxury.

What about the restriction the grid operator imposes on you and throttles you or the feed-in?

You mean the 70% rule? Over the course of the year, it hardly plays a role. Because 70% of the nominal capacity is calculated under optimal radiation conditions. Most roofs are neither perfect in orientation nor in pitch, and even then the sun has to hit your roof at nominal capacity first. If you don’t have a pure south-facing roof, you almost never reach the 70% anyway, and for pure south-facing roofs there is also the 70% soft rule, meaning only the feed-in is throttled to 70%, your simultaneous self-consumption can fill the gap to 100%. Ten years ago, the feed-in tariff was higher, but so were module prices. While in the past one fed in completely, a system today should achieve a certain self-consumption. This is also the reason why (for pitched roofs) an east/west orientation is preferred over a pure south-facing roof, which nominally yields more per m².

There are two types: a maximum of 70% or participation in [Einspeisemanagement]: 100%-60%-30%-0% ... In the case of a pure south roof, that is the question. A battery in the basement is, in my opinion, uneconomical.