Desalinization is merely removing the salt from sea water. The world is 2/3 water, but most of it is undrinkable.
Removing the salt is easy, and 300 million people do it. There are several ways, but every way is very expensive. For a very long time, people living in deserts or other places (like California) where water is hard to get have been trying to find a way to cost effectively.
This may be the way to do it MUCH cheaper on a small scale basis. And ANYONE can do it.
If you want know more, read the article, you will enjoy it! In case you are wondering, I consider this to be way more important than Rod Stewart fixing potholes.
https://spectrum.ieee.org/solar-desalination-tech
