[The_Virginian]

bravo.

[UIUCstudent01]

Turning wind into water.

Water = the main sustaining resource for life.

Therefore, if there were similar projects all over the world, this could seriously help alleviate the 'die-off'.

Alot of life can be sustained with today's technology - I don't think the human race will revert to be a feudal/agrarian/whatever society - and that means alot of sustainable tech will become profitable as Peak Oil is realized. I hope at least.

I wish that the energy saved by (over*)demand destruction would go into sustainable technology programs like this. Hopefully.

*I'm assuming that demand destrution will be below the actual production. Therefore, sustainable projects become attractive in the long run.

[gg3]

My initial take on this topic title was skepticism, given that desalination is so energy-intensive that I normally think of it as being powered by nuclear reactors.

However, on second thought, this is one area where the intermittency of wind doesn't matter *at all*. It would be trivial to build a desal plant on a modular basis with a number of modular units running in parallel, and then use appropriate automatic switchgear to direct as much power as was available, to as many units as could be supported, on practically a moment-to-moment basis.

And also, one could locate plants on platforms at sea, surrounded by wind turbines, in areas that aren't ordinarily considered useful wind energy sites because they're not feasible for grid connection. The fresh water would be pumped into tankers for transport to population centers.

One could also utilize grid-connected wind farms during off-peak hours, producing water with the overnight power surplus.

[And_over]

Energy Efficient Desalinization: I was watching a Discovery Science Channel program about desalinization of ocean water. Apparently, they've devised a new methiod of removing salt from water that requires less then half the normal amount of energy, and only costs 66 cent per cubic meter, less than many other sources. Their are desalinization plants in California that already use the technology. Perth, Australia will finish a plant that uses the technology by the end of the year. It will provide almost all of their water requirements. Sydney is also about to begin a plant that will come online in 2008. California has an additional 6 plants finishing permitting.

So let's review:
Energy Efficient
Low Cost
Already in use
Being scaled up

This will go a long way toward solving the water and energy problems in large coastal areas.

[toadster]

Was it talking about the desalinization technique that uses nanotechnology?

[Heineken]

I was watching a Discovery Science Channel program about desalinization of ocean water. Apparently, they've devised a new methiod of removing salt from water that requires less then half the normal amount of energy, and only costs 66 cent per cubic meter, less than many other sources. Their are desalinization plants in California that already use the technology. Perth, Australia will finish a plant that uses the technology by the end of the year. It will provide almost all of their water requirements. Sydney is also about to begin a plant that will come online in 2008. California has an additional 6 plants finishing permitting.

So let's review:
Energy Efficient
Low Cost
Already in use
Being scaled up

This will go a long way toward solving the water and energy problems in large coastal areas.

But if the cost of energy doubles, as it soon will, you're back to where you started.

[Graeme]

Nuclear desalination

New solutions to the ancient problem of maintaining a fresh water supply is discussed in a special issue of the Inderscience publication International Journal of Nuclear Desalination. With predictions that more than 3.5 billion people will live in areas facing severe water shortages by the year 2025, the challenge is to find an environmentally benign way to remove salt from seawater.

A. Raha and colleagues at the Desalination Division of the Bhabha Atomic Research Centre, in Trombay, point out that Low-Temperature Evaporation (LTE) desalination technology utilizing low-quality waste heat in the form of hot water (as low as 50 Celsius) or low-pressure steam from a nuclear power plant has been developed to produce high-purity water directly from seawater. Safety, reliability, viable economics, have already been demonstrated. BARC itself has recently commissioned a 50 tons per day low-temperature desalination plant.

Co-editor of the journal, B.M. Misra, formerly head of BARC, suggests that solar, wind, and wave power, while seemingly cost effective approaches to desalination, are not viable for the kind of large-scale fresh water production that an increasingly industrial and growing population needs.

India already has plans for the rapid expansion of its nuclear power industry. Misra suggests that large-scale desalination plants could readily be incorporated into those plans. "The development of advanced reactors providing heat for hydrogen production and large amount of waste heat will catalyze the large-scale seawater desalination for economic production of fresh water," he says.

eurekalert

[Judgie]

Nuclear desalination

New solutions to the ancient problem of maintaining a fresh water supply is discussed in a special issue of the Inderscience publication International Journal of Nuclear Desalination. With predictions that more than 3.5 billion people will live in areas facing severe water shortages by the year 2025, the challenge is to find an environmentally benign way to remove salt from seawater.

A. Raha and colleagues at the Desalination Division of the Bhabha Atomic Research Centre, in Trombay, point out that Low-Temperature Evaporation (LTE) desalination technology utilizing low-quality waste heat in the form of hot water (as low as 50 Celsius) or low-pressure steam from a nuclear power plant has been developed to produce high-purity water directly from seawater. Safety, reliability, viable economics, have already been demonstrated. BARC itself has recently commissioned a 50 tons per day low-temperature desalination plant.

Co-editor of the journal, B.M. Misra, formerly head of BARC, suggests that solar, wind, and wave power, while seemingly cost effective approaches to desalination, are not viable for the kind of large-scale fresh water production that an increasingly industrial and growing population needs.

India already has plans for the rapid expansion of its nuclear power industry. Misra suggests that large-scale desalination plants could readily be incorporated into those plans. "The development of advanced reactors providing heat for hydrogen production and large amount of waste heat will catalyze the large-scale seawater desalination for economic production of fresh water," he says.

eurekalert

Hmmm, perhaps the initial Chinese version should have the coolant and desalination loops as the one loop?

[Tanada]

Happened to catch the end of a Beyond Tomorrow episode about the new 97% efficient presure exchangers being retrofitted to RO plants world wide. These things are now so efficient that they claim it would be cheaper for LA to desalinate seawater than to pump water to LA from distant resevoirs.
I couldn't find much online but I did find: THIS,which has the following:

Beautiful engineering halves desalination energy costs
Submitted by rgmerk on Wed, 12/10/2005
Ah, I'm enjoying Beyond Tomorrow. This week's offerings (included with the usual bits of wacky cars and repeats of Mythbusters is perhaps the cleverest piece of technology I've seen in years. Reverse osmosis is generally desalination method used in newer commercial desalination plants the world over; it's the one that's going to be used for the desalination plant that will be built in Perth, and the one planned for Sydney. The process is simple, in principle - you pump the seawater into a special pipe with a membrane that only lets the water through, and not the salt. One pipe with seawater goes in; a pipe with fresh water and a pipe with super-salty brine comes out.

It works, and works well; the only problem is that it's much dearer than water from dams, and the primary reason for that is that desalination is very energy-intensive. To make it work, you need to pump the water in at very high pressure. Both the brine and the fresh water come out at a very high pressure, though, which is a waste in the case of the brine. Wouldn't it be great if we could recover the waste energy from pumping the brine? Well, systems already do that, but they're not terribly efficient at it; you get back maybe half the waste energy, at best.

This company has built a new system, and it's just beautiful in its simplicity. There's a rotating gadget with multiple chambers in it. First, a low-pressure pump fills the chambers with seawater. Then the chamber rotates around such that the other end of the chamber is exposed to the high-pressure expelled brine, which pushes the seawater into the osmosis chamber. However, when the brine has pushed out all the non-salty water, the thing has rotated around again, so that chamber gets filled with seawater at low pressure and the brine is expelled...and so on and so forth.

The detailed hydrodynamics of the system are undoubtedly far more complicated than that (and probably required thousands of hours of modelling with computational fluid dynamics simulations), but the upshot is that the system apparently recovers about 97% of the energy used pumping the brine. That's an absolutely huge difference. Consequently, instead of the 4.93 kilowatt hours per kilolitre estimated by the Sydney Institute for the Sydney desalination plant proposal, these guys claim a figure of about 2.40 kilowatt hours per kilolitre. That's 50% off the energy cost.

However, that's not the end of the story. These guys are collaborating in a industry-government collaboration in the US to put a bunch of these more efficient desalination technologies together. As well as the energy recovery system, they are using new RO membranes that work at lower pressures, and much more efficient desalination pumps. They reckon they can get the energy consumption down to between 1.5 and 2.0 kilowatts per kilolitre.

By the way, it's interesting to note the wildly different capital cost estimates used by the Sydney Institute and the energy recovery device makers. In their cost model, they quote a capital cost for a 120,000 cubic metre per day plant of 100 million USD. This is roughly consistent with the latest and biggest desalination plant in the world, Israel's Ashkelon plant, which will produce about 273,000 kilolitres per day and has a capital cost of about 212 million USD> The Sydney plant would put out 500,000 kilolitres per day. If you scale that up from the estimate in the cost model, you get a capital cost of about 416 million USD, or, roughly, about 600 million Australian dollars. It seems like the economics of desalination aren't nearly as bad as its detractors make out; however, they're still probably very unattractive compared to recycling.

[FreakOil]

From the article:

The key to the success is a technology called "reverse osmosis". Essentially this involves water being pushed through a membrane or filter at a very high pressure. That high pressure means it uses a lot of energy. At the Ashkelon plant they have cut the costs by building their own power station as part of the unit.

This is the Achille's heal of desalination. I suppose you could use nuclear power, and that's another reason for Iran to build its own nuclear power plants.

[Tanada]

From the article:

The key to the success is a technology called "reverse osmosis". Essentially this involves water being pushed through a membrane or filter at a very high pressure. That high pressure means it uses a lot of energy. At the Ashkelon plant they have cut the costs by building their own power station as part of the unit.

This is the Achille's heal of desalination. I suppose you could use nuclear power, and that's another reason for Iran to build its own nuclear power plants.

While I advocate Nuclear fission for all sorts of uses desalination via osmosis just needs pressure. You can get that pressure from intermittent sources because you can resevoir the fresh water easily enough, sources like wind and solar coupled with water towers to keep pressure steady when they are off line will prodive you with lots of drinking and irrigating water, coupled with these new energy efficient pressure exchangers just makes it cheaper.

[mekrob]

From the article:

The key to the success is a technology called "reverse osmosis". Essentially this involves water being pushed through a membrane or filter at a very high pressure. That high pressure means it uses a lot of energy. At the Ashkelon plant they have cut the costs by building their own power station as part of the unit.

This is the Achille's heal of desalination. I suppose you could use nuclear power, and that's another reason for Iran to build its own nuclear power plants.

While I advocate Nuclear fission for all sorts of uses, desalination via osmosis just needs pressure. You can get that pressure from intermittent sources because you can reservoir the fresh water easily enough, sources like wind and solar coupled with water towers to keep pressure steady when they are off line will prodive you with lots of drinking and irrigating water, coupled with these new energy efficient pressure exchangers just makes it cheaper.

Couldn't you just make the tower of seawater very high and have the membranes and tubes near the bottom? Or are the pressures needed for it to work simply too high for this to be feasible? Is it also not economical to "simply" process the remaining brine into the components (salts, metals, etc) for further industrial uses? Or is that simply too unrealistic?

[Tanada]

From the article:

The key to the success is a technology called "reverse osmosis". Essentially this involves water being pushed through a membrane or filter at a very high pressure. That high pressure means it uses a lot of energy. At the Ashkelon plant they have cut the costs by building their own power station as part of the unit.

This is the Achille's heal of desalination. I suppose you could use nuclear power, and that's another reason for Iran to build its own nuclear power plants.

While I advocate Nuclear fission for all sorts of uses, desalination via osmosis just needs pressure. You can get that pressure from intermittent sources because you can reservoir the fresh water easily enough, sources like wind and solar coupled with water towers to keep pressure steady when they are off line will prodive you with lots of drinking and irrigating water, coupled with these new energy efficient pressure exchangers just makes it cheaper.

Couldn't you just make the tower of seawater very high and have the membranes and tubes near the bottom? Or are the pressures needed for it to work simply too high for this to be feasible?Is it also not economical to "simply" process the remaining brine into the components (salts, metals, etc) for further industrial uses? Or is that simply too unrealistic?

That's what I was talking about when I said water towers, pump water into a series of water towers filled with filtered seawater and then let gravity provide the presure at a steady rate. This system would not requir constant power, the pumps would fill the towers when power was availible from intermittent sources. Only when water was running low in all the towers would baseload sources be needed to sumplement pumping power.

It is not economical to process the remaining brine to recover salt unless you were doing so on a large scale already, salt doesn't sell for much money and you need a huge acreage of dessert land to dump out the brine and let it evaporate. To evaporate as much brine as you process to make freshwater for human use is some orders of magnitude too much salt for economic recovery.

[Graeme]

Windmill With A Twist Can Provide Fresh Water From Seawater Directly

A traditional windmill which drives a pump: that is the simple concept behind the combination of windmill/reverse osmosis developed by the Delft University of Technology (TU Delft) in The Netherlands. In this case, it involves a high-pressure pump which pushes water through a membrane using approximately 60 bar. This reverse osmosis membrane produces fresh water from seawater directly.

sciencedaily

[FourOfSwords]

That's an encouraging story.
Alex.

[Tanada]

How is this a new thing, water pumping windmills have been around for about a thousand years and reverse osmosis has been around for about 50. How is mating these two together in any way a breakthrough when all of the components are off the shelf technology?

[jlw61]

How is mating these two together in any way a breakthrough when all of the components are off the shelf technology?

Anyone who can take off the shelf technologies and combine them in a way to potentially solve a problem is worthy of at least a solid congratulations.

Genius is the act of seeing the obvious.

[Heineken]

As always, the devil will be in the details. Scalability. Maintenance. Cost. (Wonder what those "membranes" cost, and how often they have to be replaced?) Other problems that will emerge because we can't know them in advance. By the time everything gets shaken out, the benefit/cost ratio of these gizmos is usually modest at best.

[aflurry]

this board suffers from schitzophrenia sometimes. Why does this technology have to be scalable? this is a local technology, suitable for small, local implementation. suitable for some (not all) of Heinberg's "lifeboats." maybe not suitable for business as usual, but that's kind of the point isn't it?

If I understand the description its virtue is that is considerably simplifies an existing process, eliminating electrical storage, which itself addresses a scalability concern. eliminating several lossy energy conversions: mechanical, to electrical, to chemical, back to electrical, back to mechanical. there are huge advantages in this being a purely mechanical operation, maintenance and cost are definitely one. and the membranes have been in use with standard reverse osmosis setups and are known, right? it seems like this is a step forward that we are calling two steps back...

I like the comment that water is easier to store than electricity. It makes me think that with the right geography it may be preferable to pump and bank fresh water into reservoirs rather than generate and store electricity, giving this a broader application. You could then generate electricity as needed with the stored water, and use the water itself after it has generated the electricity. Until then, the water sits as a non-toxic resource.

[Tanada]

It occured to me today that out west in the New Mexico-Colorado-Idaho axis of the country that there are several saline aquifers. If you drill a well into one of these saline aquifers, run the resulting water through a reverse osmosis plant to recover some 40% of the water as potable fresh water and sell it to the ranchers & farmers in the Los Alamos region you would have to figure out what to do with the concentrated saline discharge.

Any suggestions other than picking a dry lake bed and just dumping it out where nature will eventually evaporate it away? With a 100,000 m^3 day plant that would give you 150,000 m^3 discharge stream. Now while that sounds like a lot if you are dumping it into a large dry lake bed the desert heat and lack of humidity is going to evaporate it pretty rapidly. If that doesn't work for you you could always dump it into the Great Salt Lake, unless Utah has some objection.