Electricity From Salty Water

[FarCenter]

A device that gleans usable energy from the mixing of salty and fresh waters has been developed by University of Milan-Bicocca physicist Doriano Brogioli. If scaled up, the technology could potentially power coastal homes, though some scientists caution that such an idea might not be realistic.

Extracting clean, fresh water from salty water requires energy. The reverse processmixing fresh water and salty waterreleases energy. Physicists began exploring the idea of extracting energy from mixing fresh and salty waters, a process known as salination, in the 1970s. They found that the energy released by the worlds freshwater rivers as they flowed into salty oceans was comparable to "each river in the world ending at its mouth in a waterfall 225 meters <739 feet> high," according to a 1974 research paper in the journal Science. But those who have chased the salination dream have collided with technological barriers.

Brogioli has developed a new approach to salination, a prototype cell that relies on two chunks of activated carbon, a porous carbon commonly used for water and air filtration. Once he jump starts the cell with electric power, all that is required to produce electricity are sources of fresh and salty water and a pump to keep the water flowing. When the separate streams of salty and fresh water mix, energy is released.

<snip>
http://www.physicscentral.com/buzz/blog/index.cfm?postid=8192106608311312838