Energy Recovery Rides Clean Water Wave

While oil seems to be a scarce commodity, some say that water could soon be just as precious, if not more so.

The reason why is a classic supply-demand quandary: The amount of fresh water remains constant at 3% of all water on Earth. But according to the United Nations Population Fund, global consumption will double every two decades. So in 13 years, the International Water Management Institute estimates, one-third of the world's population will face a severe water shortage.

That puts some pressure on figuring out a way to make the other, saltier 97% of the world's water drinkable. And, increasingly, water desalination plants are popping up to do just that. The catch is, those plants themselves suck up a lot of energy, making them economically undesirable outside of places like the Middle East, where energy costs are cheap. ...