Author Topic: Blue Energy: A potential source of renewable energy  (Read 1184 times)

FayeforCure

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Blue Energy: A potential source of renewable energy
« on: March 17, 2009, 12:14:16 PM »

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Blue Energy: A potential source of renewable energy
What do you get when saltwater and fresh water meet? A clean, renewable source of power called blue energy.

Diane Daniel | March 2009 issue


Photo: istoockphoto.com/rustycloud

The blades stutter a bit at first, but after a couple of halting starts, the tiny propeller on the miniature windmill is soon turning at top speed. The fuel: a tank containing saltwater and fresh water. "Here's your proof," says Jan Post, a Ph.D. student at the Dutch water technology research institute Wetsus. "Blue energy works."

This little windmill is just a laboratory demonstration model, but Post and his colleagues have big ambitions for blue energy, a process that derives clean power from the mixing of saltwater and fresh water. Within a decade or so, they hope blue energy will produce a significant share of the Netherlands' electricity. But if the technology that powers the windmill can be scaled up, blue energy could do a lot more. Along with other renewable sources of power like solar and wind, it could help make sustainable energy a reality.

Blue energy—or reverse electrodialysis (RED), its technical name—derives power from an unlikely source: energy released from the process of osmosis. Whenever two solutions of differing concentrations meet—tea and coffee, for example, or saltwater and fresh water—they blend so the concentration becomes equally distributed throughout. Pour saltwater and fresh water togethrr and you get brackish water, in which salt is spread evenly within the solution. This process releases energy.

In a RED system, saltwater and fresh water are brought together through an alternating series of ion-exchange membranes, which harvest the energy released as the fresh water is drawn towards the saltwater. And Post's miniature windmill isn't the only device running on blue energy. Last June, Redstack, a company affiliated with Wetsus, began a trial at a salt factory in the Dutch town of Harlingen. So far, the experiment is only yielding enough power to run a vacuum cleaner, but it's a start. "The trial has to run trouble-free for a couple of years before you can consider a real power station, but it looks good," says Post. "Investors are ready to step in."

One of the attractions of blue energy is that power plants can be situated wherever saltwater and fresh water meet—in other words, wherever rivers flow into the sea, from the fjords of Norway to Asia's estuaries. The plants could even be located underground, placing minimal impact on communities and land. Westus researchers believe the 19-mile Closure Dike in the northern Netherlands, which divides the fresh water Lake IJssel from the saltwater Wadden Sea, is the perfect place for a blue energy power station.

http://www.odemagazine.com/doc/61/blue-energy/

Seems perfect for Jacksonville and the St Johns River.

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Jason

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Re: Blue Energy: A potential source of renewable energy
« Reply #1 on: March 17, 2009, 01:03:52 PM »
Couple that with tidal generation and wind turbines and this could be fool proof.

Doctor_K

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Re: Blue Energy: A potential source of renewable energy
« Reply #2 on: March 17, 2009, 02:01:39 PM »
OK cool; but then what? 

Where do you dispose of the brackish water?  Just dump it?  Thus creating virtual seas of artifically-created brackish water? 
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Jason

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Re: Blue Energy: A potential source of renewable energy
« Reply #3 on: March 17, 2009, 02:34:44 PM »
If the system is setup at river mouths then yeah, just dump the brackish water back into the ocean.  The water is already mixing there anyway.  The system doesn't creat excess brackish water, just capitalizes on a process that is already taking place.