Question: Is silicon useful in solar panels (as I remember reading about it)?

Peter Burgess answered on 10 Nov 2015:

Yes, it’s crucial to most solar panels. There are a small number of other materials that can be used but silicon accounts for maybe 95% of the world’s solar power. Any panels you see on a roof around your neighbourhood are going to be made using silicon cells.
Until about ten years ago, silicon for solar panels was simply the leftovers from the computer industry. As solar power has grown, we have had to develop our own solar silicon factories and now solar uses about five times more silicon that the computer industry.
It’s not going to run out though, silicon comes from sand.