I placed one solar panel in a polluted chunck and another with no pollution at all.
Both have the same power output.
The 2nd solar panel does not supposed have more power output ?

Individual solar panels of the same type/kind cannot have different power outputs. But, there is a per-surface/planet modifier that can adjust the effectiveness of solar power. So, each solar panel's effectiveness is adjusted based on its individual characteristics, but this is aggregated into one single modifier that affects all panels. The end result is the same, but you won't notice differences between individual panels' tooltips.

Oh right, I see! I don't have to worry about that then, thanks. :)