"The ocean is an unforgiving place," says Susan Hunt. "But our technology is designed to operate there - it goes up and down in the waves, all day and all night."

Ms Hunt is chief innovation officer for a Canadian start-up called Oneka Technologies. It has developed floating desalination systems that turn seawater into fresh water.

While large, shore-based desalination plants typically require vast amounts of energy to remove the salt, Oneka's small units are powered solely by the movement of the waves.