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Electricity From Salty Water
BuzzSkyline writes "It's possible to produce energy by simply mixing fresh and salty water. Although chemists and physicists have long known about the untapped energy available where fresh water rivers pour into salty oceans — it's equivalent to 'each river in the world ending at its mouth in a waterfall 225 meters [739 feet] high' — the technology for exploiting the effect has been lacking. An Italian physicist seems to have solved the problem with the experimental demonstration of a 'salination cell' that creates power given nothing more than input sources of salty and fresh water. The researcher believes that this renewable, environmentally friendly energy source could be deployed in coastal areas and could provide another addition to the green-tech roster. A paper describing the technology is due to be published in an upcoming issue of the journal Physical Review Letters."
Quick! Grab all your salt shakers and run to the bathtub!
leather-dog muksihs
Blog: @muksihs
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.
Forget scaling it up. Put one such device in every fresh water toilet bowl.
Only if the waterfall is on the edge of the ocean...
Actually the technology was already available, and is to be used to power most the majority of homes in the Netherlands, including mine, if the proposal is approved:
http://ecoworldly.com/2009/03/08/saltwater-power-could-supply-energy-for-most-dutch-homes/
Or the original publication:
http://pubs.acs.org/doi/full/10.1021/es9004224?cookieSet=1
I thought our food chain was Sun -> Corn -> Cows/Pigs/Chickens -> Cows/Pigs/Chickens -> Dinner.
https://www.eff.org/https-everywhere
There have been other ways to extract salinization energy: http://en.wikipedia.org/wiki/Reverse_electrodialysis
These methods are even being used in test sites to generate power. Main problems are that there's a lot of crap in rivers that you need to filter out to get high efficiencies.
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
Don't bother. PETA and Greenpeace both called and said it'll kill too many endagered fish species.
Fish? Oh, you mean sea kittens.
The article actually has an interesting addendum at the end that explains it, albeit in an interesting vernacular.
In short, salt water is ionic. A small initial electric charge is given to the two pieces of carbon (one positive, the other negative). The sodium and chlorine ions migrate to the respective carbon and thanks to the very high surface area of activated carbon, you get a very high quantity of ions. The water source then switches to fresh water. Elecrostatic force tries to keep the sodium & chlorine ions near the carbon but diffusion pulls them away. The work done to pull the ions away is what generates the power.
The inventor that it can generate as much as 1.6KJ / Liter of fresh water. If we diverted 10% of the Missisippi River's outflow into one of these facilities you get ~2.6GW of more or less continuous power. (Mississippi = 572,000 ft^3/s * 28.32 L/ft^3 x 10% x 1.6KJ = 2.6GJ/s = 2.6GW)
I've been on slashdot so long I'm starting to get out of touch with the cool stuff if it ain't on slashdot.