Abu Dhabi using waste heat to produce clean water

One of the Gulf states, Abu Dhabi has lots of natural gas and plenty of spare heat, with some of the hottest temperatures recorded on our planet during their summer. As a result, the thermal efficiency of its gas turbine plants, even when run on a combined cycle (where waste heat powers a secondary steam generator) is only about 41 percent, compared to up to 60 percent in more temperate climates. So far, not so good.

But while Abu Dhabi has lots of gas and lots of heat, it doesn't have a lot of fresh water. With 1.7 million people and a need for around 240 million gallons of fresh water a year, that means desalination. Removing salt from sea water requires a fair amount of energy, with the easiest method being flash distillation; you use heat to turn the water into steam, leaving the salt behind. By using the waste heat of their gas turbines to desalinate sea water, Abu Dhabi is able to turn that 43 percent efficiency into more than 90 percent efficiency, which is fairly impressive by anyone's standards.