From the article: 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?

Veolia's Desalination Costs Triple on Energy Prices (Update2)
June 26, 2008. - Veolia Environnement SA, the world's biggest water company, said the cost of purifying seawater has tripled because of higher energy prices, squeezing profit margins.
The cost of producing water from desalination plants may have risen to as much as $1.60 per cubic meter from as low as 50 cents "in the last few years,'' Jean-Michel Herrewyn, chief executive officer of Veolia Water Solutions & Technologies, said in an interview in Singapore yesterday.

Power is the largest cost at a desalination plant, which filters millions of gallons of seawater into drinking water by straining out salt, bacteria and minerals. Industry margins at desalination plants, typically between 10 and 15 percent, are shrinking as fuel costs increase. "The cost curves are going up,'' Herrewyn said. ``If we have to reduce the price of desalinated water, we have to reduce the price of energy.''

Veolia shares fell 32 cents, or 0.9 percent, to 35.73 euros at 1:49 p.m. in Paris today. The stock has lost 43 percent this year, compared with a 20 percent decline in the CAC 40 Index, on investor concern over profit margins due to currency losses and higher cost inflation on water and waste projects. Profit targets may be "difficult to achieve,'' Veolia Senior Executive Vice President Jerome Contamine said in a posting on French financial Web site LeRevenue.com last week.

Low Margins: Crude oil has doubled in the past year and touched a record $139.89 on June 16, while natural gas futures in New York have gained 70 percent this year, pushing up costs of producing electricity. Almost 700 million people in Asia lack access to clean water and about 2 billion are without adequate drainage, according to Manila-based Asian Development Bank.

"Water is a much slower developing market because the margins are low,'' said Lisa Henthorne, president of the International Desalination Association. "We can't charge 50 to 100 percent margins for bulk water because it is still a social good.'' The margins in desalination are between 10 and 15 percent, she said. Even so, sales in Asia's water-purification market will increase by as much as 20 percent in the next three to five years, outpacing the world, Herrewyn said. Veolia may get "very sizeable'' municipal contracts for desalination, reuse and recycling in the range of $100 million, he said.

Rising Pollution: "The booming economies of China and India are very attractive,'' Herrewyn said in a Bloomberg TV interview today in Singapore. "One of the main, if not the leading, growth areas now is the Middle East.'' Rising levels of pollution in developing economies are creating more opportunities for business, Dan McCarthy, chief executive officer of Black & Veatch Corp., a U.S. engineering and construction company that provides water-treatment services, said in a TV interview today. "We do focus on the hot developing marketplaces because they do have challenges from very basic needs,'' McCarthy said. The public is "looking at sustainable solutions more aggressively than they had before.''

China's government plans 1 trillion yuan ($146 billion) of spending to build waste water-treatment plants in the five years through 2010, the Ministry of Construction said in August. As many as 278 cities lack proper treatment facilities, it said.

Water. It's quite important to the human body. Arabs are going to be in serious trouble if they don't invest in solar power soon.

I can't imagine why they aren't using a solar process to desalinate the water in the first place. Why not just paint a pool black. Put a clear cover over it. Fill it with seawater. Run cool seawater through some pipes near the cover and collect the condensate from the outside of the pipes. Viola...solar distillation. Ultra low tech, and requires minimal energy input.

a few million gallons a day is not going to change the face of the mideast either. Natural evaporation takes place over the entire surface of the ocean. Desalination takes the brine and concentrates it one place. Not a problem for one plant. As a solution to third world water shortage? I have my doubts.

I also have doubts as to how eco-friendly this technology will be if deployed on a large scale. It is not just the brine discharge that is a problem. The intake is a problem as well. You are sucking in not just salty water, but marine organisms as well. Typically these organisms end up dead by the time they are finally discharged from the RO plant. Then their is the discharge. The salt concentration doubles from 35,000 ppm in the water intake to 70,000 ppm in the brine discharge. And you are not just concentrating salt, you are concentrating chemicals and pollutants as well. There are approaches you can take to minimize the ecological impact of both the intake and discharge(sandy soil pre-filtration, large area diffusers, etc.), but these are not always applicable in all areas.

THERE is a lot of water on Earth, but more than 97% of it is salty and over half of the remainder is frozen at the poles or in glaciers. Meanwhile, around a fifth of the world’s population suffers from a shortage of drinking water and that fraction is expected to grow. One answer is desalination—but it is an expensive answer because it requires a lot of energy. Now, though, a pair of Canadian engineers have come up with an ingenious way of using the heat of the sun to drive the process. Such heat, in many places that have a shortage of fresh water, is one thing that is in abundant supply.

Revelant to oil, in that a cheap desalination method powered by the sun would make sense for Middle Eastern countries and possibly California (using solar rather than oil to desalinate water)

http://www.technologyreview.com/blog/energy/24337/

As a groundbreaking idea, this is right up there with hand washing or dodge ball

Even the best reverse-osmosis plants require 3.7 kilowatt hours (kWh) of energy to produce 1,000 litres of drinking water.Mr Sparrow and Mr Zoshi, by contrast, reckon they can produce that much fresh water with less than 1 kWh of electricity, and no other paid-for source of power is needed. Their process is fuelled by concentration gradients of salinity between different vessels of brine. These different salinities are brought about by evaporation.

the low pressure of the pumps needed (in contradistinction to those employed in reverse osmosis) means the brine can be transported through plastic pipes rather than steel ones. Since brine is corrosive to steel, that is another advantage of Mr Sparrow’s and Mr Zoshi’s technology.