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New Rechargeable Battery Uses Water

Posted by samzenpus on from the I-want-my-water-engine dept.

fergus07 writes "Scientists at Stanford have developed a battery that uses nanotechnology to create electricity from the difference in salt content between fresh water and sea water. The researchers hope to use the technology to create power plants where fresh-water rivers flow into the ocean. The new 'mixing entropy' battery alternately immerses its electrodes in river water and sea water to produce the electrical power."

4 of 179 comments (clear)

  1. Re:ALready an energy shortage there. by Ferzerp · · Score: 3, Informative

    Wait, you actually think water is disappearing, going poof? Where do you think this water is going? Water is not something you use up and then there is no more. You see, it evaporates, and then it rains down again clean. Now it may not be where you expected it would be, or it may end up unfit for use in areas with contaminants, but the water is still there.

    You realize there are nearly inexhaustible supplies under the ground right? If you suck it out faster than it seeps back down, guess what, the water still exists. We could potentially use it faster than we harvest it, but to assert that water is a scarce resource is very, very misleading. You can always expand your collection techniques.

    Or are you suggesting we are in danger of locking up *all* of the hydrogen and oxygen on the earth in to other compounds?

    Oh, you know that salt water? Let it evaporate, and magically you have more fresh water. :P

  2. Isn't this already in practice elsewhere??? by dr.Flake · · Score: 4, Informative

    I know the plans to put one of these into service are almost finalized in The Netherlands, spanning the "afsluitdijk"
    http://wikimobi.nl/wiki/index.php?title=Zoet/zout_watergrens

    But i think the Norwegians beat us all to it:

    http://www.statkraft.com/energy-sources/osmotic-power/

    --
    Why are other peoples sig's always more witty ???
  3. Re:Great News for Environment! by wjousts · · Score: 3, Informative

    From TFA:

    Because river deltas and estuaries are sensitive environments, the Stanford team designed their battery to have minimal ecological impact. The system would detour some of a river's flow to produce power, before returning the water to the ocean. The discharge water would be a mix of river water and sea water, and released into an area where the two waters already meet.

  4. As always, it's a scale problem. by tacokill · · Score: 4, Informative

    So, 13,000 gallons per second of fresh water flow and we can get around 100MW. Let's go on a math exercise, shall we?

    The average combined cycle plant is (at a minimum) around 400MW. Not including co-gens, etc. Just normal power plants sitting out in the middle of nowhere. Fukishima is around 4900MW. Fukishima isn't really fair because it is, by any measure, a large nuke plant. But, 400-1200MW is not an unreasonable range for "typical" power plants in the US, regardless of the technology used (coal, nuke, combined cycle, direct fire, etc)

    At 400MW, you are talking 52,000 gallons PER SECOND of water flow. That, by any measure, is a shitload of flow. At 1200MW, we are talking 156,000 gallons per second.

    For comparison, I just looked up the flow rate of the Mississippi river at the high water dam near Lake Itasca. Going thru the Upper St Anthony's falls lock and dam, the flow rate is around 90,000 gal/sec.

    So for ONE reasonably sized power plant, you would need fresh water flow that is the equivalent of the Mississippi River.

    As I said, it's a scale problem.