Traditional solar panels 

These rigid solar panels are polycrystalline, monocrystalline or amorphous, they are usually placed in roofs.
Amorphous panels have a much lower surface yield but produce more in gray weather. The polycrystalline photovoltaic panels have a surface yield a little less important but have an incomparable power / price ratio monocrystalline photovoltaic panels have in addition to having the highest efficiency, have black cells which gives them an added cachet.