Cheaper desalination

The Economist: There is a lot of water on Earth, but more than 97% of it is salty and over half of the remainder is frozen at the poles or in glaciers.

Meanwhile, around a fifth of the world’s population suffers from a shortage of drinking water and that fraction is expected to grow.

One answer is desalination—but it is an expensive answer because it requires a lot of energy.

Now, though, a pair of Canadian engineers, through a company called Saltworks Technologies, have come up with an ingenious way of using the heat of the Sun to drive the process. Such heat, in many places that have a shortage of fresh water, is one thing that is in abundant supply.

A test plant in Vancouver, Canada, will open this month.