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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
he key ingredient in a salt-water capacitor is "activated carbon," extremely porous carbon made from wood, coal, or coconut shells.
Gilligan could have lived well on that island.
...for pissing in a swimming pool?
So can we expect this to work in parallel with existing hydro power generation techniques?
Typo in the summary:
Obviously that should be "researcher"
"The reearcher believes that this renewable, environmentally friendly energy source..."
Don't bother. PETA and Greenpeace both called and said it'll kill too many endagered fish species.
I hope the Energizer Bunny owns water fins and a snorkel!
Are you looking to build a perpetual motion machine?
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 both processes are 100% efficient. Neither can be.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Keep in mind desalination is
salt_water -> salt + water
whereas this reaction is
water + salt_water -> less_salty_water
You'll note that they're not exactly inverses of each other.
Don't bother. PETA and Greenpeace both called and said it'll kill too many endagered fish species.
While PETA and Greenpeace may have different definitions of "too many" than you do, balancing concern about impacts on fish stocks with concerns about energy is a perfectly reasonable thing to do, given that fish are part of our food supply (and food chain).
There's also issues like whether or not a given fresh water supply might have better uses.
Tweet, tweet.
It produces less (laws of thermodynamics are a bitch). But you point out an interesting way to describe it to people. i.e. It takes energy to desalinate sea water, this process is sort of like running desalination in reverse to generate energy.
The world is made by those who show up for the job.
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
You're only thinking in terms of the United States, you insensitive clod! Think about someplace like Bangladesh. They have a hell of a rainy season, and a seacoast. Last I checked, a fresh water shortage wasn't a big problem for them. At least during the rainy season. Potable water? Yes. Unsalted water? No.
Too late, Exxon already bought the patent.
Technically, they don't have to be for our purposes.
The fresh water streams exist due to an external power source, Sol.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
There are serious transportation issues with piping potable water from places where it is plentiful to places where it is needed. That's WHY we have a potable water crisis in some areas (especially the American Southwest) while we have no problem whatsoever in others (like the Northeast or the mouth of the Missisippi). In those places there's already huge amounts of water flowing into the ocean. This technology would allow that water that is already being mixed with ocean water to generate electricity in the process.
Also there are situations where water is not potable due to issues other than salinity, and for the purposes of this process might be considered "fresh" compared to saline water.
An interesting thing would be if this could be used to provide for cheap solar power - Some of the largest "solar power" we use today are salt concentration ponds - they don't provide electrical power BUT they do provide the function of separating salt from water in large solar ponds. It would be horrendously inefficient per unit of surface area, but the cost is so low that large surface areas could be achieved.
retrorocket.o not found, launch anyway?
... I understand people don't read the articles, but did you even bother to read the summary?
It would be impractical to do it anywhere else.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
If you RTFA (pardon me, I forgot this is SlashDot) the same effect can be gotten by mixing salt water with more highly salinated water (made by evaporating sea water - say, using a solar evaporation pool) or lightly polluted water (non-potable).
I could also venture a guess, based on the fact this is a solution postulated for coastal locations, that the process could also be sited at or near the mouth of a river - say one the empties into the sea or ocean? In that case only fresh water that was destined to end up mixed into salt water would be used.
...carrier dead.....
It would be interesting if this could make desalinization more energy efficient. After you finish desalinization you end up with clean water and very salty water. If you mixed the less salty sea water with your now very salty water, could they recover part of the huge amounts of energy that desalinization requires?
Diplomacy is the art of saying, 'Nice doggie!' till you can find a rock.-- Wynn Catlin
Clearly, every time I take a leak, I could be generating power from the mixing of my salty urine with clean water during the flush. Also, I should be pissing onto a tiny waterwheel hooked up to an electric generator, and there should be a Francis Turbine on the flush release outflow.
Next, we'll poop right into a methane extracting farm, and we'll inject pine cones into each person's lungs to extract the exhaled CO2 directly.
It's perfect!
So that's how Farrah powered her blow dryer inside the dome! Identify Logan 5-thousand watts, baby!!
This is actually really interesting! Think about it. We've been limited to solar cells for a long time for producing electricity, and those have limitations we are constantly struggling against. But... Now, you can make a simple isolated enviroment consisting of water and salt. Design it such that fresh water runs down from a resivoir into a lower resivoir with salt. Expose the lower resivoir to sunlight, and use the greenhouse effect to speed up the evaporation of the water. Direct the vapors up to the upper reservoir, where they precipitate out, and flow back down! Thus, we generate electricity and use the sun to separate the two components to repeat the cycle. (plus if you want, you can capture the heat from the condenser, for even more energy) Not something you could put in your car, but on a large scale I bet this could work. Similar to large steam powered plants.
Actually, it doesn't need fresh water, just a saline gradient. So one could easily use brackish->sea water or even sea water->higher salinity water from evaporation ponds.
Technically, you could even use the "waste" output of a desalination plant, but of course that wouldn't recover anywhere near the energy put in.
I hope you're joking about the people from the southwest being self-centered thing, cause otherwise, wow, you need to fucking get out and meet people more.
It certainly seems like it would work just fine to run it on straight salt instead of saltwater though, so the equations still mostly work. The water in saltwater is just serving as a handy salt transport mechanism. I can't imagine a practical application for running it on pure salt, although I suppose some survivalists might be a fan of it for a home generator. It's certainly easier to store salt than most typical fuels.
People from California tend to be pretty self-centered when it comes to regional issues
FTFY
This is a huge problem for Los Angeles. Ever seen "Chinatown"?
(-1, Raw and Uncut is the only way to read)
"Brogioli maintains that his salinity cell could be ramped up faster than other salination approaches and could be made as affordable as solar power in a decade or so."
As affordable as Solar in a decade? Solar's main problem now is it's cost!
One of the best places (potentially) to grow algae for biofuels is in the desert. You could pump seawater inland, and circulate it in pools. If you covered those pools with greenhouses (which could just be big clear balloons... or not-so-big ones, if you use arrays of small pools) and collected water they'd make you some fresh water, which could then be combined with incoming salt water to produce energy to help run the system, whether that would be the pumps, mixing devices which keep the pools circulating, or what ever else have you.
Another idea for the waste water produced from this process is to pump it inland and use it in the algae pools... so you can have coastal plants whose effluent is used to grow algae for carbon-neutral biofuels, and [optionally] to raise the water table in the desert.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
This would be a great way to power all those desalinization plants on the coast!
æeee!
If only it were that simple:
http://washasia.wordpress.com/2009/06/12/bangladesh-cyclone-leaves-trail-of-contaminated-water-sources/
http://www.wateraid.org/bangladesh/about_us/5458.asp
I looked at the diagram and it showed that it needs to be hooked up to a charge and ground? It looks like they are just transferring the charge into capacitors while using the salt as an electrolyte?
I'm sure this works, otherwise we wouldn't be talking about it seriously, but my primitive mind can't see WHERE the net energy is coming from the salt water.
Could someone help me out and explain?
Thanks!
Weirdly, it could power some. Take their example of mixing brackish and salt water to get electricity (or salty with very salty). Use the electricity to desalinate.
The world is made by those who show up for the job.
Windmills convert wind into electricity. The result...less wind on the far side. That changes climate I'm guessing. Not sure how wind affects things. Hotter animals because of less breeze? Smaller area of seed dispersal? Other things.
Solar panels take the heat energy out of the sunlight and convert it to electricity. I'd think that would cause the ground to heat up less, but that's probably insignificant compared to the direct change of 'being in the shade' for all the flora and fauna under the solar panels.
What do the hot/cold water exchange generators do? I would expect that pumping cold water from the ocean warms up the ocean...but that would be putting energy INTO the water instead of extracting it. So I'm a little confused. Lets just say it 'changes the ocean temperature'. That's enough to disrupt the ecosystem.
With this salty water thing. Whose energy are we stealing? If there's some sort of exothermic reaction going on in all river mouths, there's definitely something that's evolved to take advantage of that. Energy on the planet doesn't just SIT there doing nothing. (cept Oil...nobody uses Oil but us. :) ) What's the result of the environmental impact study? (I don't just mean habitat loss...I want to know who specifically was harvesting that energy.)
--Welcome to the Realm of the Hawke--
I read this summary extremely skeptical but after reading the article (which is pretty sparse on detail) it sounds simple enough to work. In principle.
The problem is this sentence:
Pumping water is a notoriously is a notoriously energy expensive process. That's why we try to use gravity as much as possible to move our water around. The question is if this process produces enough energy to offset the cost of moving in and out of the (presumably) mixing chamber. If the answer is no, then this grinds to a screeching halt right then and there.
This stuff about X process is equivalent to Y incredibly energetic phenomena is misleading. There's incredible amounts of energy locked up in just about anything. It's just that our technology is such that our extraction processes suck. We're terrible at it. Think about cars. Of all the ways we know of motivating four wheels, we choose to process processed hydrocarbons we dug up from the bottom of the ocean. There's basically an infinite amount of energy in the sky in the form of wind alone. We're just terrible at taking it out.
So some process that claims to potentially harness some percentage of the electrical energy of a 100 meter waterfall? I'd like to hear about it when they build the thing and it actually lights up a bulb. Till then, it's just a concept.
And Carbolic acid out too, while producing electricity, then we would have the utopia machine.
Keep in mind desalination is
salt_water -> salt + water
Show me a single commercial example where this is the case.
Desalination is:
lots of salt_water -> lots of slightly_saliter_water + a little fresh_water
High rejection ratios help reduce the energy requirements as greater temperatures or pressures (depending on the method) are required for greater salt concentrations.
that's the thing, most everyplace as 'regional issues'. Though most don't involve basic necessities of life like, ahem, water.
Having grown up in the Northeast, I'm amazed at the lack of 'natural issues' the Northeast has. Extremely rare tornados, hurricanes and earthquakes. No appreciable landslide risks, forest fires hardly ever happen (i.e. it's wet), no active volcanoes. There's the acid rain thing, but that's manmade.
Build your house away from trees, with a high sloping roof (snow) and a supply of firewood and there aren't many natural disasters likely to even phase you.
And yes I've lived in other parts of the US, it's only then that you learn to appreciate the things you took for granted.
People in cars cause accidents....accidents in cars cause people
I hope you're joking about me being joking, 'cause otherwise, wow, you need to get out and experience more of the world.
need new "Missed Funny(+1) By *That* Much" moderation....
People in cars cause accidents....accidents in cars cause people
The article described these things as small environmentally friendly devices. They may not pollute the water and they may be small, but I cannot help but wonder what type of impact they could potentially have. The article states that one of these devices could power small house. However, a lot of homes and buildings exist in places near the joining of rivers to oceans. This would give reason to place a lot of these devices in these deltas. However, to my admittedly limit knowledge on the subject, some animals and plants live in the deltas and typically avoid other areas. If deltas are overrun with these devices, what will the environmental impact be? Are these devices going to greatly change the methods and ways of life for the delta-dwelling creatures when the devices are placed in great numbers throughout the delta? If so, they may not be as environmentally safe as the researcher wants people to believe. Also, if great numbers of these devices are placed in the mouths of rivers and deltas, is the movement of silt into and through the deltas going to be disrupted? I do not know the answers, but these are the questions I have when he claims to have what seems to be a perfect energy source (for certain areas) and then states it is environmentally safe.
This could spell the condemnation of every species that have evolved to live in brackish water...
Nice to see somebody talking about energy from water salinization once in a while, but that is not the first experiment to gather a few microjoules at lab. Up to now, no aparatus could be scaled up, all of them hit that "we just need better materials" barrier. There is a reason for that, because of the way difusion works, each device can create at most 100mV, and that will fall almost exponentially down to near 10mV once one starts gathering more than 5% of the available energy.
Just put that on the right perspective, there are just a few specialized diodes that will dissipate less than 100mV on the charge going through it. A normal silicon diode will dissipate 700mV, and there is simply no diode that will dissipate less than 10mV. Also, to get some sane amount of power at 10mV one needs quite a big current, the charge is available to extract that current, but the resistence of your circuit (and the capacitor's dieletric is a piece of the circuit) is a huge barrier. To create 1kW, one'd need a total current of 10^5A (of ions flowing into and out of the coal, if not electrons flowiong throug the circuit), with a total resistence of 10^-7 ohms. To reach such small reistences it is normaly needed lots and lots of material, or "just" better material.
Rethinking email
Hey, that's not entirely true! Water shortages in the US are also caused by people farming on the prairies and pumping out the aquifers. Water shortages in the Third World typically aren't half so much water-shortages as potable water shortages.
The World Wide Web is dying. Soon, we shall have only the Internet.
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.
It isn't a water problem, it's a stupid people problem.
But people are mostly made of water, so now you have a stupid water problem...
My webcomic
Yup, you could place those facilities at the deltas of rivers for a never-ending supply of fresh water which would otherwise go unused. Only try not to kill too many salmons in the process.
... I understand people don't read the articles, but did you even bother to read the summary?
I DONT READ THE ANYTHING I JUST POST PANICY THINGS IN THE HOEPS THAT SOMEONE REACTS.
please justify my existence.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
Actually that might work out well!
Think 2 plants both running on solar power during the day.
At night, the water/salt from plant number 2 are recombined to power plant # 1!!!
Never heard of osmotic pressure? It's not that complicated. (O.P. = iMRT) Just convert that pressure into electric energy...
AC was being a dick, but you just brought up a completely different point. The first issue you mentioned was lack of potable water. The second issue was destruction of estuaries. These two things are not related. While destruction of estuaries is at least possibly an issue (and I'm quite positive you don't know for sure, you just want to seem smart and concerned about the planet, so you bring up anything you think might possibly be an issue, but you are JUST GUESSING,) the idea that we could get fresh water out of estuaries is NOT, as pointed out so eloquently by our dickish AC friend.
However, this slip is not the most hilarious part of your posts. In order to see what the really, really outrageously funny part is, consider the impact on estuaries of extracting fresh water from them. I'll wait...
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
. . . maybe Chef was on to something here . . .
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
It produces less (laws of thermodynamics are a bitch). But you point out an interesting way to describe it to people. i.e. It takes energy to desalinate sea water, this process is sort of like running desalination in reverse to generate energy.
This makes a lot of sense. Much in the same way it takes energy to say... read books for example. If we simply unread lots of books we could actually generate power.
Looks like US schools are heading up this green initiative.
I think the author just got a call from the cold fusion guys...
To all you virgins: Thanks for nothing.
This technique doesn't require potable water, only salt-free water.
Not even salt-free. It requires two sources of water where one is much less salty than the other.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Thanks for the link to the informative publication. :(
I have no mod points
Carbolic acid: A very old name for phenol. It's toxic, and you do not want this in seawater.
Carbonic acid: What you get when CO2 dissolves in water. Not harmful, and found in ample quantities in cabonated drinks.
In chemistry, spelling does matter.
Those who would give up liberty to obtain working drivers, deserve neither liberty nor working drivers.
Every process has a time component. That's why it's called a process. Some are fast and some are slow.
Your input to this otherwise closed system is the sun and hinges on how quickly you can convert the water's state into gas.
The evaporation of the water is not "sped up" by a greenhouse effect. A greenhouse is a natural consequence of water evaporating in a closed system. If anything, it will slow down as the humidity increases until it reaches an equilibrium with the rate set by how much water you're taking out of the water in the form of precipitation.
The only way to speed up the process is to add more energy. That's a lot of mirrors.
I might be mistaking but this is called Blue Energy. Real world trials are already being build in the Netherlands (finished 2010). KEMA (Dutch institute) has discovered a way make cheap polymer membranes I believe. Dutch source: http://www.energiechannel.nl/nieuws_details.php?nid=44
I read that as "In a decade, as affordable as solar will be then," not "as affordable as solar is now." Most of the projections on solar have it coming into equivalence with natural gas before a decade's out. Coal may still be cheaper, if it's being burned in a grandfathered, totally polluting plant.
Some of use also prefer cheap, polluted women. Lord knows I do! But my utility gets none of its power from coal. The price is slightly lower than average for here in the Northeast US. Unemployment is lower than the rest of the region too. Obviously it's not killing the economy to source from power suppliers priced higher than the coal generators.
"with their freedom lost all virtue lose" - Milton
You're right. What's the point of life when we have to steal energy from the Earth in order to live?
If you truly care about the environment, you'd shoot yourself and return your chemicals back to the planet.
Don't forget to tell us how works out.
As such, any time we find a new source of power, you can damn well bet nature has gotten there first, and that our exploitation of said power will have negative consequences for the species already using it.
This sentiment of yours is dangerous in the sense that it is wrong yet rational enough that too many people could believe it.
Nothing was using the energy stored in uranium or oil until we got around to using it. And neither us nor any other creature is harnessing e.g. the energy of deuterium and tritium contained in seawater. Nothing is even using the energy of the sun shining on the desert.
Another problem with your idea: energy cannot be really "used", it can only be directed elsewhere. Sooner or later every form of energy will change into heat. We cannot stop this, but before it takes place we can transform energy into other forms to do something useful. Example: when the sun shines on the desert, it is converted to heat straight away. But when we put solar panels there, we can redirect a part of the energy to our homes and use the energy from the sun there, where in the end it will also be turned into heat.
I could go on about how humans are not artificial, but part of nature, but the main premise of your post is already invalidated so I'll stop.
Those who would give up liberty to obtain working drivers, deserve neither liberty nor working drivers.
Please mod parent up to at least try to stop the similar nonsensical rambling of fringe environmentalist groups that attempt to induce a sense of guilt in people in order to extort donations.
Reasonable environmental policies: yes.
Voluntary human extinction: no.
Those who would give up liberty to obtain working drivers, deserve neither liberty nor working drivers.
Oh, you don't think people in Arizona and Nevada are just as self-centered when it comes to water usage?
The correct correction would be "People tend to be pretty self-centered when it comes to regional issues".
We hope your rules and wisdom choke you / Now we are one in everlasting peace
I hope you're joking about the people from the southwest being self-centered thing, cause otherwise, wow, you need to get out and meet people more.
You know, the main point of that post was that water shortages in the US are a regional problem. Interesting that what you got out of it was that it was all about you.
I have mod points here, but I didn't see any other posts addressing this point, so I'll say it instead.
The big problem with all of these kinda wacky energy schemes (from the perspective of energy independence and global warming advocates who clamor for these things) is that none of them show any potential of producing enough energy to measurably offset the use of any of our major energy sources like oil, gas, coal, and nuclear. It may be cool and there may be a useful niche for it somewhere, but unless you can get at least gigawatts if not tens of gigawatts or more reliably, then it won't have any effect on our importation of fossil fuels or overall global carbon emissions. And there's also the question of how much other environmental damage and disruption would be caused by deploying something like this on a multi-gigawatt scale.
I don't reply to ACs
less_salty_water is salt_water nonetheless.
FTA: The Mississipi delta, where the freshwater river pours into the salty Gulf of Mexico, would be an enormous source of energy if we could tap it.
It would be a HUGE bad idea to try to tap into the Great Lakes and try to cart all that water over to the ocean or something.
Tons of water is already being diverted to dry states like Arizona, and being used on farms and bottled water.
Seriously though, even though the Mississippi dumps a bunch of freshwater into the gulf, you've gotta think that changing the chemical balance has got to have repercussions.
Day After Tomorrow anyone?
River deltas house some unique ecosystems. Has anyone done an environmental impact study on using something like this?
See
http://www.panda.org/about_our_earth/ecoregions/about/habitat_types/selecting_freshwater_ecoregions/habitat17.cfm
Is this realy news? there are already a prodjects in Norway and in Dutch where thay are building power plants using this consept More info can be found here: http://peswiki.com/energy/Directory:Mixing_Sea_and_River_Water Allso there is this post "Russians were First On Oct. 7, 2007, Wesley Bruce wrote: Statkraft's press release is, I believe, incorrect. I believe the Russians have an osmotic power plant running near Vladivostok. The plant may have only been experimental but it did sell power. I saw it on a TV report, Beyond Tomorrow I think, It had a web site in Russian but its since disappeared. Statkraft may be the first big plant but I don't think it counts as the first to sell power. The Russian team may even be working for Statkraft now " from http://pesn.com/2007/10/07/9500451_Statkraft_osmotic_power_plant/
I hope this can work on a massive scale. Cheap, accessible, green energy available at all income levels will work for social justice. Today, access to massive energy is only available to the wealthy.