Polycrystalline solar panels are also made from silicon, but the type of silicon used is slightly less pure and they are cast into blocks rather than sawn from a single crystal. The fact that the crystals are randomly arranged means that they are visible individually.
Once the polycrystalline ingot is cast, it is sawn into square blocks and then sliced into square wafers that are processed to convert them into solar cells.
Here’s a close up of a polycrystalline solar cell – you can see that it looks very different to the sleek, uniform appearance of its monocrystalline rival:
The easy way to spot mono solar panels on a roof is to look for the tell tale white diamonds between the cells.
Polycrystalline solar cells are very similar to monocrystalline in performance and degradation, except in multicrystalline, the resulting cells are typically slightly less efficient. However, as you can see here, there is no wasted space between the corners of the perfectly square cells:
This means that when they are encapsulated in solar PV panels, there is slightly more area available to absorb sunlight. The result is that a polycrystalline solar panel’s performance is just a notchlower to monocrystalline solar panels due to their efficiency being a bit lower. Here’s what they’ll look like on your roof: