The MIT solution essentially maximizes the amount of fresh water that can be recovered from power plants. By introducing electrical forces into fog-rich air, the typical aerodynamic problems that prevent water collection are circumvented, and gathering more clean water is possible.



The system was developed in response to a problem that targets water deficient coastal areas: approximately 40 percent of all fresh water gathered from US lakes and rivers is reserved for cooling down power plants, but the fog-harvesting systems in place -- metal or plastic mesh hung vertically -- were only managing to trap a very small percentage of the targeted water droplets. Because of an aerodynamics issue, tonnes of potentially drinkable water was turning into vapor.



Associate professor Kripa Varanasi saw a way to minimize that wastage. If fog-rich air was zapped with ions (charged atoms or molecules), then ensuing water droplets would become electrically charged -- which would in turn allow them to directly gravitate towards a mesh of wires and drain into a collector. The benefits of the new system are multifold -- not only does it allow a more efficient way of gathering drinkable water, it uses low-cost materials that would help power plants reduce operating costs.



The team also invested in capturing water from the plumes of power plant cooling towers. They're a much more concentrated source of water vapor compared with fogbanks, and therefore, allow the MIT system to work even more efficiently. Varanasi says that annually, the average 600-megawatt power plant could capture up to 150 million gallons of water which would otherwise be wasted.