|One of the biggest problems is the availability of clean water. A group in Egypt may have found an answer which uses free energy from space—the sun, in other words.
Innovative System to Extract Water from Air Using Solar Energy describes a way to extract water from the air using free energy from space. It works by adsorbing water during the day out of the air and collecting it in a tank at night. It costs about $100 to build and just works to produce up to 2.3 L of water per square meter.