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New Rechargeable Battery Uses Water
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."
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
Like, recharging your flashlight at the urinal.
Gently reply
We could use the generated electricity to power desalinisation plants.
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 ???
Toyota already did with their Prius. I think the official term is "smug".
After the battery is discharged, the salt water is drained and fresh water is added to begin the cycle again.
This is awesome, we can use up all our fresh water and would have an unlimited supply of salt water!
From TFA:
I think he's talking about taking water and sending it to Arizona where it then evaporates in the desert and doesn't actually make it to the end of the river. I'm guessing of course. But as for these "inexhaustible" supplies under ground, you should read about the supply in the midwest which requires drilling to new depths because it is being depleted. Should you think going deeper is always an option, you may want to read the recent stuff of fracking to see how the deeper water is being deliberately contaminated. There are solutions to these, problems, but what we are doing vs what we could be doing don't really match.
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.