The cost of electricity is increasing. One kilowatt-hour of green electricity from the grid currently costs around 30 euro cents. If you generate it yourself with the help of a photovoltaic system, you pay approximately twelve euro cents for it. However, if you feed this into the grid, you receive from the energy supplier only between 5.94 and 8.64 euro cents per kilowatt-hour as remuneration.
You don't have to take long calculations: only those who use as much solar power as possible will get their money's worth. And if you can store the electricity in a solar battery for the dark hours, you are well on the way to becoming self-sufficient when it comes to energy.