Poland is a good location to generate solar power
Generating solar power is not the biggest problem in Poland. The problem is making any money out of it (as a private person) because you cannot sell your energy back to the system. You can only give them your energy and then obtain some discount (like 80% or so) when buying energy from them later on.
Or, if you want to use your own produced energy in the night you must keep it in some batteries. But the cost of such batteries is even bigger than the solar panels what makes the whole investment completely unprofitable.