Competition suits customers, but it also carries the risk that clearing-houses will water down standards on the amount of margin they demand, for instance to win deals.

ECONOMIST: The risk in clearing-houses

While large-scale desalination is not uncommon in those parts of the world where natural water resources are scarce -- such as Texas and Australia -- the UAE is by some margin, according to Iannelli, the industry's most active player.

CNN: Counting the carbon cost of bringing water to the desert