Justin Gillis writes in the NYT that as drought strikes California, residents "can't help but notice the substantial reservoir of untapped water lapping at their shores — 187 quintillion gallons of it, more or less, shimmering invitingly in the sun."
Once dismissed as too expensive and harmful to the environment, desalination is getting a second look. [...] A $1 billion desalination plant to supply booming San Diego County is under construction and due to open as early as November, providing a major test of whether California cities will be able to resort to the ocean to solve their water woes. [...] "It was not an easy decision to build this plant," says Mark Weston, chairman of the agency that supplies water to towns in San Diego County. "But it is turning out to be a spectacular choice. What we thought was on the expensive side 10 years ago is now affordable."
Carlsbad's product will sell for around $2,000 per acre-foot (the amount used by two five-person U.S. households per year), which is 80 percent more than what the county pays for treated water from outside the area. Water bills already average about $75 a month and the new plant will drive them up by $5 or so to secure a new supply equal to about 7 or 8 percent of the county's water consumption.
Critics say the plant will use a huge amount of electricity, increasing the carbon dioxide emissions that cause global warming, which further strains water supplies. And local environmental groups, which have fought the plant, fear a substantial impact on sea life. "There is just a lot more that can be done on both the conservation side and the water-recycling side before you get to [desalination]," says Rick Wilson, coastal management coordinator with the environmental group Surfrider Foundation. "We feel, in a lot of cases, that we haven't really explored all of those options."
(Score: -1, Offtopic) by Anonymous Coward on Sunday April 12 2015, @08:25PM
Oh it's California, where every mother is a drunken marijuana smoking crack whore on heroin. Carry on then.
(Score: 2, Interesting) by Natales on Sunday April 12 2015, @08:34PM
It's about time the desalination topic start to get more coverage. 75% of the surface of the planet is covered with water. California is a coastal state. Simply dismissing desalination as a viable option is just lack of imagination.
All the problems the critics point to are really engineering problems. They can ALL be addressed with the proper technology and R&D investment. In fact, they could spur a bonanza of new technologies and start-up companies that would ultimately make desalination a a much efficient and safe for sea creatures. As I've pointed before in another thread, Saudi Arabia is building the largest desalination plant in the world [cleantechnica.com], all powered by solar. Why not California?
(Score: 2, Insightful) by SubiculumHammer on Sunday April 12 2015, @08:40PM
Agreed. Although one of the more expensive problems with desalinization is pumping the water from the coast to the central valley where 80% of California's water is used for farming.
(Score: 5, Interesting) by Adamsjas on Sunday April 12 2015, @09:44PM
Agreed, the pumping cost is always there, but it is free once you build the infrastructure.
Solar power on the mountain sides could power the whole project, including the desalination process. (if its reverse osmosis it really only needs pumps).
I've often thought that if any place could make de-sal work without burning a boatload of oil it would be California, and Arizona.
(Score: 2) by captain normal on Sunday April 12 2015, @11:34PM
"...but it is free once you build the infrastructure."
"(if its reverse osmosis it really only needs pumps)"
There is nothing "free" about running and maintaining a RO desal plant, to say nothing about maintaining any large scale solar power plant. Besides having to clean and change filters often, Pumps moving salt water have to be maintained and replaced. All not "free". Then there is the cost of keeping the intake strainers and filters unclogged . These also require constant maintenance...Also not "free". Then there is question of what to do with the heavy brine discharge (which is also quite a bit warmer than the coastal waters off California. Not an easy engineering task. This also adds to the list of parts that need constant maintenance. No or this is "free" nor is it a trivial expense.
There are much better and less costly technologies being developed. Building and blowing huge amounts of tax dollars and added water bills on maintenance will look foolishly shortsighted and wasteful in a few years.
When life isn't going right, go left.
(Score: 2) by Leebert on Monday April 13 2015, @02:37AM
Can you elaborate a bit?
(Score: 2) by captain normal on Monday April 13 2015, @03:48AM
Here is a lead to one: http://scitechdaily.com/researchers-develop-graphene-membrane-water-filters/ [scitechdaily.com]
When life isn't going right, go left.
(Score: 3, Informative) by frojack on Monday April 13 2015, @05:44AM
Sorry, Its still strictly in the world of "doesn't work." At least not for seawater desalination. Your own link says as much.
And, it has EVERY SINGLE DRAWBACK that you mentioned above for regular RO plants.
RO is proven technology, used in countries all over the world. Its well understood.
Further Solar powered small RO plants are off the shelf [dwc-water.com] products.
Large scale Solar RO [hitachi.com] plants are also well established.
On top of that, you twisted my words. I said the pumping was free by using solar power. I didn't say the entire plant was free, or never needed maintenance.
No, you are mistaken. I've always had this sig.
(Score: 2, Informative) by Anonymous Coward on Sunday April 12 2015, @08:45PM
says Rick Wilson
The dude who lives in florida and rants on twitter about everything. Yeah hes a viable source to listen to for something on the other end of the country.
SoCal specifically SD is ideal for solar. They should be in 100% on it. OH wait... they are. The company I used to work for slathered all their buildings in it. Lets just say if that company says should happen in that city, it does.
The only reason I have not put solar up on my house is because I am about to sell it. I want the ROI not the next owner. Selfish I know but hey there we are...
There are downsides with this tech. Specifically brine and waste filters. What do you do with it? Is there a way we can reuse it? Are we removing things from the environment that are needed. Things that need to be addressed. But to not do it because of these things will be short sighted on their part.
(Score: 3, Interesting) by gznork26 on Sunday April 12 2015, @09:30PM
The salt can be used to offset the huge amounts of fresh water melt entering the North Atlantic from Greenland and weakening the salinity-based current that drives the Gulf Stream. The by-product of one solution is the solution to another problem.
Khipu were Turing complete.
(Score: 2, Insightful) by Anonymous Coward on Sunday April 12 2015, @09:47PM
The by-product of one solution is the solution to another problem.
Except of the small problem of moving billions of gallons of material to the other side of the world of something that pretty much acts like a long term acid with metal. Plus the idea may or may not work? Plus what sort of organisms would you be introducing to that area that are not native? Or perhaps one organism in that stew that is prey for another but the predator can not live in that temperature/salinity range and you create a huge algae blooms?
It is not an 'easy' problem to solve and one that could cause many others. Go slow but dont stop! It is a good idea. But do not be so quick to say you have a plan to fix it.
If you could pump that much sludge from greenland to socal you would be better off going the other way... Probably from the great lakes would be easier.
(Score: 1, Touché) by Anonymous Coward on Sunday April 12 2015, @11:53PM
That would be an equally valid complaint to make against relocating oil, yet someone finds the economic benefit suffucient to outweigh the cost of doing it. Who cares if a few environments and species are devastated when (not if) the spills occur, right? It's just a statistical cost of doing business.
(Score: 2) by frojack on Sunday April 12 2015, @10:09PM
So ship this salt all the way to the Atlantic then?
No, you are mistaken. I've always had this sig.
(Score: 1, Interesting) by Anonymous Coward on Monday April 13 2015, @02:24AM
Put the salt in blue cylindrical boxes and sell it.
Want to really draw in the suckers?
Mention that it's SEA salt and that it's ALL NATURAL. [wordpress.com]
-- gewg_
(Score: 4, Informative) by mendax on Sunday April 12 2015, @11:26PM
Well, not really. Given that the water from desalinization plants will be used in cities, most of it will eventually end up back in the ocean anyway after passing through treatment plants.
Honestly, the best way of dealing with a drought in a city is to reuse the water you already have. Water that goes through the sewage treatment plants is drinkable when it comes out. It really ought to simply be pumped back into the fresh water supply.
It's really quite a simple choice: Life, Death, or Los Angeles.
(Score: 4, Interesting) by Hartree on Sunday April 12 2015, @11:34PM
They've been trying to get water consumers to accept that for some time. The problem is that human thought just can't get over the idea that it's recycled toilet water no matter that it's absolutely pristine pure after treatment. So, instead they treat it somewhat and then inject it back in the ground to recharge the aquifer. More expensive, and not as effective, but the consumers will accept it as somehow being different water than the waste water.
It's the same idea as a toddler not wanting "that" juice. So you put it behind your back so they lose track of it and magically now it's different juice. ;)
(Score: 2) by frojack on Monday April 13 2015, @06:15AM
They've been trying to get water consumers to accept that for some time.
No they haven't.
No where in North America is sewer outfall considered safe to drink. Even after tertiary treatment. Good enough to water lawns, wash cars, flush toilets, but not for drinking or cooking.
No, you are mistaken. I've always had this sig.
(Score: 3, Informative) by Hartree on Monday April 13 2015, @08:43AM
It requires more than just tertiary treatment but it is already being used here in the US.
Here's just one organization that's brought it up: https://www.watereuse.org/foundation/research/DPR-Initiative [watereuse.org]
One of the members of WateReuse Research Foundation is American Water which (among many other places) supplies the water for much of East Central Illinois where I live (My town is independent of them, but where I work, the University of Illinois and Urbana Illinois are supplied by them.)
Here's another article where both Big Spring, Texas and Wichita Falls, Texas are already doing it: http://www.wateronline.com/doc/texas-leads-the-way-with-first-direct-potable-reuse-facilities-in-u-s-0001 [wateronline.com]
There was a whole bunch of PR done about it a couple years ago on NPR and other media outlets.
Yes, they use it as input to their existing potable water treatment plant as 50/50 mix with raw water and it never goes back into the aquifer.
The comment previous to me mentioned sewer plant output being drinkable directly, and I think that's what you conflated with mine. But even with further treatment, there is considerable public push back on DPR.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @09:46AM
Given that the majority of water use is for watering lawns, washing cars, flushing the toilet and similar activities, and only a minor part actually goes into drinking, that's fine. You also might use that water for agriculture, another big consumer of water where no one would mind using treated sewage water — after all, for organic food you put animal excrements on the fields!
(Score: 3, Interesting) by HiThere on Monday April 13 2015, @06:11PM
The Black Diamond water company got around that by bottling the water and selling it as "water from the Black Diamond" in a different location. (I think Black Diamond was a coal mine, but I never checked.) But it *was* recycled sewage. Possibly the ran it through the coal mine after treating it, but I don't know that they even did that. (I only saw a short article about it once in, I think, the 1980's. You might check out http://www.ci.blackdiamond.wa.us/homepage.html [blackdiamond.wa.us] if you're interested enough.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 3, Informative) by frojack on Monday April 13 2015, @06:10AM
Water that goes through the sewage treatment plants is drinkable when it comes out.
Ummm, No. Not really. Nowhere except perhaps the ISS.
http://www.beachapedia.org/Sewer_Systems_and_Sewage_Treatment [beachapedia.org]
Reclaimed water (also sometimes called recycled water or tertiary treated water) is wastewater that has gone through primary and secondary treatment and typically additional filtration and/or chlorination/dechlorination. It is often used for irrigation of parks, golf courses, and general landscaping. It is not suitable for drinking.
There are other issues as well, such as drugs. [scientificamerican.com]
Even with tertiary treatment, water is not safe for drinking due to frequent lapses in these systems, and their inability to remove drugs.
Re-injection into ground water, and outfall into estuary water systems isn't a cheap shot. Its an essential step in the recycling process.
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @09:39AM
If it saves the future owner money, then it should rise the amount you are able to get from selling the house, shouldn't it? That is, you'd get your ROI when selling the house.
(Score: 3, Informative) by mtrycz on Sunday April 12 2015, @08:47PM
I don't know the details, and could be plain wrong, but discussion here on Soylent on ths topic a while ago pointed to the problem not being of the engeneering kind, but economic.
Can't find the comment now, but the point was that the water is sufficient, but it's sold to farmers for a very low price, they can farm the hell out of the land with it. Since it isn't abbundance, market "laws" would say that the price of water should rise, but a subtle "please" from a few big farmers to a few big decision makers keep it low.
Hence the shortage.
In capitalist America, ads view YOU!
(Score: 1) by Natales on Sunday April 12 2015, @09:22PM
The Wikipedia entry [wikipedia.org] has some interesting numbers on the actual costs: "Achievable costs in 2013 range from 0.45 to 1 US$/cubic metre (2 to 4 US$/kgal). (1 cubic meter is about 264 gallons.)".
(Score: 4, Funny) by Anonymous Coward on Sunday April 12 2015, @08:35PM
https://i.imgur.com/Zl836nj.jpg [imgur.com]
(Score: 2) by hemocyanin on Sunday April 12 2015, @10:22PM
I was expecting goatse, but that was amusing. (spoiler: one duck stands on another partially sinking the other)
(Score: -1, Troll) by Subsentient on Monday April 13 2015, @02:20AM
I got something better than goatse. http://www.tubgirl.ca/tubgirl.jpg [tubgirl.ca]
"It is no measure of health to be well adjusted to a profoundly sick society." -Jiddu Krishnamurti
(Score: 3, Informative) by hemocyanin on Monday April 13 2015, @02:48AM
Been there before, don't want to go back. Ever. Tubgirl makes Goatse look G rated.
(Score: 0) by Anonymous Coward on Tuesday April 14 2015, @01:39AM
Been there before, don't want to go back. Ever. Tubgirl makes Goatse look G rated.
Seriously. It's been twelve years since a 3 second viewing and just thinking about it still makes me gag.
(Score: -1, Troll) by Anonymous Coward on Sunday April 12 2015, @08:42PM
Says the guy who doesn't want me to have a beautiful green lawn in San Diego.
If I don't have a beautiful green lawn then ISIS wins.
'Merica.
(Score: 1, Interesting) by Anonymous Coward on Monday April 13 2015, @02:29AM
Folks (especially folks who actually live in SoCal) need to realize that most of the state is desert.
When you think of Cali, you should be getting the same image you get when you think of the rest of the desert southwest like Arizona or New Mexico.
In the midst of the foreclosure mania of the last several years, some cities have been hitting property owners with fines for unkempt unoccupied properties and/or with charges for having city workers|contractors actually bringing those up to code.
Something folks have discovered is that it's cheaper not to water grass but to instead go with an artificial solution.
SoCal Homeowners Spray-Painting Lawns Green To Avoid Water Fees During Drought [cbslocal.com]
In Santa Ana, they recently did a street-widening project and replaced all the grass there with astroturf.
Even if the sun bleaches it and you have to go back and paint it every few years, it beats the hell out of having to mow it constantly.
...and there are lots of succulent plants that are both green and drought-tolerant.
As an example, aloe vera is really cheap because it reproduces like crazy when it gets water.
...and the guy in north Orange County who ripped out his lawn in 2010 [google.com] is looking like a genius (and his city, which busted him for violating their dumb code, looks more stupid).
-- gewg_
(Score: 2) by Justin Case on Sunday April 12 2015, @09:04PM
For years I've been hearing "peak water" "water is the new oil" and of course the alarmists' favorite: we're all gonna die!
Somehow, people were able to figure out how to refine pure gold from mountains of dirt once the incentive got high enough. I'm sure obtaining pure water will be somewhat easier.
Let supply and demand set the price of water and:
1. Water consumers will be more motivated to conserve and reuse.
2. Water producers will be more motivated to get creative about increasing the supply.
All without the heavy hand of government! It is almost as if some problems will work themselves out, if we simply step back and stop meddling.
(Score: 5, Informative) by Fluffeh on Sunday April 12 2015, @09:42PM
Here in Australia, we've been using desalination plants [wikipedia.org] for quite a while - even the last (linked), the Sydney plant was brought in on time and under budget. Although it is currently used as a top-up service to the main reservoir when there isn't enough rainfall, it is expected to become a always-on system over the next decade or so as the population increases.
(Score: 1, Insightful) by Anonymous Coward on Sunday April 12 2015, @10:47PM
It's one thing to be government owned and operated, but in Ca it will most likely be corporate owned with a lot of taxpayers footing the bill, then cost overruns, everyone wanting to rape the piggy bank, etc. By the time it gets built it'll be an oozing pustule of costs and not worth it.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @02:32AM
I say we do a pilot program.
We find a tiny uninhabited desert island and drop you off there alone then sail away.
You get to take as many greenbacks with you as you like.
You will quickly find out what is like for people who have no money.
-- gewg_
(Score: 0) by Anonymous Coward on Monday April 13 2015, @09:50AM
Most people who have no money are not alone.
(Score: 3, Insightful) by Anonymous Coward on Sunday April 12 2015, @09:19PM
I've had the concept in my head for a long time of using nuclear power to desalinate ocean water and solve our county's water problems. Build a fleet of the latest safest reactors to power desalination plants along the coast of California. (If its safer to put the reactors elsewhere in the state do it.) Why nuclear? It doesn't pollute the atmosphere with carbon (and other nasty things), and the waste can be contained and moved around instead of pumped into the air. Solar, wind, and geothermal could help power this setup, but I don't think they can provide enough regular power to make this work by themselves.
Start by providing all the water for LA and San Diego, then build a pipeline/aqueduct to Phoenix so that when their aquifer runs out, they have a source of water. Use nuclear reactors that are NOT a once through fuel setup so they don't use obscene amounts of uranium -- perhaps a design like the IFR or a LFTR, that's a question better answered by nuclear engineers. Then build industrial facilities to extract as many useful things (like salt) from the brine before we throw it back into the sea. Take any reasonable precautions to protect sea life from the desalination process. Fund all this federally. Saving California is worth it for the whole country. Not to mention that a huge public works project like that would be a great economic stimulus.
I have a concept in my head to address nuclear power's biggest weakness, corporate corner cutting and mismanagement, if anyone is interested in hearing it, reply to this comment, and I'll type it up.
(Score: 0) by Anonymous Coward on Sunday April 12 2015, @09:27PM
> build a pipeline/aqueduct to Phoenix so that when their aquifer runs out, they have a source of water.
Better build at least a couple miles a year, because Phoenix only has 100 years' worth of water left... that we know about.
(Score: 0) by Anonymous Coward on Sunday April 12 2015, @09:33PM
I have read that their main aquifer only has about another 30 years of water left.
(Score: 0) by Anonymous Coward on Sunday April 12 2015, @09:28PM
Why not jump on the thorium bandwagon?
(Score: 2) by c0lo on Sunday April 12 2015, @09:32PM
I have a good place on mind: San Andreas Lake
(grin)
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by kaszz on Monday April 13 2015, @01:49AM
Use solar concentrators instead?
Nuclear reactors near the coast in an earthquake zone with a lot of people and corporate corner cutting.. hmm ask the Japanese how that works out.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @06:36AM
Parent AC poster here.
I agree that corporate profiteering and corner cutting are a MAJOR problem with nuclear, in fact probably the largest flaw of that method of energy production. There was another plant that was similar to Fukushima at Onagawa. You can read the whole story here. [oregonlive.com] The short version is that the corporate people wanted a cheaper cooling system, and a lower seawall. One of the men involved insisted upon, and got, a taller seawall, and a cooling system that could deal with the lack of water from a tsunami. Onagawa survived the tsunami without any major problems. They got cheap at Fukushima.
I propose a possible solution to this corporate problem -- socialization and nationalization. While I won't write up my whole proposition, basically the short version is as follows. Nationalize the entire nuclear power generation industry. Pay everyone that works at a plant at least double, if not triple the going wage for their job. Now, here's the kicker: When people take those jobs, they become liable to the full extent of their assets if the plant melts down. This applies especially to the administrators at the top, and goes all the way down to the guy sweeping the floor. So, if the plant goes, so do the houses, cars, and all the money of those responsible. Basically, financially speaking, the workers and administrators marry the plant. Who is going to want to risk their gravy train by cutting corners?
Now, since the government has a magical power of being able to operate enterprises for the public good at a loss (like the military), the nuclear arm can run with a different set of priorities. Instead of the usual corporate priority -- profit, profit, more profit, and some profit after that; the nuclear arm can run with the priorities of safety, producing the energy that the country needs, and seeking to break even economically, in that order.
All that being said, if the renewables can truly ramp up to provide the energy necessary to desalinate and pump enough water to meet California's demand, that would be great. When I think the epic amount of energy necessary to desalinate, purify, and then pump most of the water California needs, I just don't see the renewables being able to do it alone.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @10:06PM
The liability point you bring up is interesting, but I don't think it would work because it is too long-term. Tie the liability to frequent external safety reviews so there is an immediate consequence that is less financially catastrophic. This would have the added benefit of catching problems early that may be missed by internal reviews.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @02:44AM
Heh. Find the most expensive method ever devised to boil water|generate electricity and use it to make the most expensive potable water ever.
Meanwhile, Cali get pounded with petawatts of sunlight.
March 24, 2015
California Is The First State To Get More Than 5 Percent Of Its Power From Solar [thinkprogress.org]
-- gewg_
(Score: 2) by wonkey_monkey on Sunday April 12 2015, @09:22PM
Water, water, everywhere, so let's all have a drink.
- Homer Simpson
systemd is Roko's Basilisk
(Score: 3, Funny) by Hartree on Sunday April 12 2015, @11:27PM
"It was terrible. We had to survive on food and water for days!"
(Score: 1, Informative) by Anonymous Coward on Sunday April 12 2015, @09:36PM
A homeowner with 4 people, 1 bathroom, no lawn watering, average bill is $130 per month. Broken down... 5000 gallons of Water $40, Sewer charge $60, System & Infrastructure charge $30. This is a highly watersaving household. Welcome to Southern California, owned and operated by the public utilities.
(Score: 1, Insightful) by Anonymous Coward on Sunday April 12 2015, @09:54PM
supply and demand
that's what you get for building on a gold rush wasteland
(Score: 1, Interesting) by Anonymous Coward on Sunday April 12 2015, @10:06PM
Ah, but we save on heating bills. Gas & Electricity is still expensive, but we don't have air conditioning so that bill is still under $100 per month tops. Housing costs are outrageous, but my mortgage was paid off in 10 years by creative financing. The only thing to worry about is earthquakes and a$$holes. I also just installed six 50 gallon rain barrels to water the veggie garden, it's just enough to provide that water requirement between rainstorms here. Our water use is half the average use.
(Score: 5, Funny) by hemocyanin on Sunday April 12 2015, @10:27PM
I live in NW WA state -- I just leave the tap running -- saves wear and tear on the washers in the handle.
(Score: 2) by kaszz on Monday April 13 2015, @01:51AM
How did you pull that off?
(Score: 1, Funny) by Anonymous Coward on Monday April 13 2015, @03:11AM
2. transfer your balance to another CC with a free interest on balance xfer for 6-12 month
3. repeat at the end of period
(Score: 0) by Anonymous Coward on Sunday April 12 2015, @11:18PM
A desalination plant near Perth, Western Australia has a solar plant next to it, which seems like the perfect match to me.
If the desalination plant isnt required to operate 100% of the time, it can work when their is excess power available and store the result (clean water).
(Score: 3, Interesting) by subs on Sunday April 12 2015, @11:57PM
On paper it seems like a reasonable idea, until you run the numbers on it. Desalination is typically done by one of two methods: evaporation or reverse osmosis. Evap is about 1.5x as energy intensive as reverse osmosis and needs sizable amounts of land, but is relatively cheap to implement. Reverse osmosis is more energy conserving and compact, but much more expensive to implement. Now solar also needs lots of land and given that it's typically ~20% efficient, even if you drove reverse osmosis with it, it'd still be about 2-3x less efficient in terms of space usage than a simple evap plant. Not to speak of expensive! First the expensive solar cells & then a reverse osmosis plant.
Put simply, if you want to use solar power to desalinate water, just use the sunlight directly and cut out the middle man.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @01:40AM
It would be neat if solar thermal energy and desalination could be combined. Pump salt water into tower, heat with mirrors, separate.
(Score: 2) by kaszz on Monday April 13 2015, @01:56AM
So how would a plant that uses solar concentrators for the thermal energy to evaporate sea water, condensate it and sterilize work out economically?
Or even more advanced. Use solar concentrators to cook water such that it's pushed through an osmosis filter?
Both solutions without using electricity as a power carrier. Nor any nuclear dirty stuff.
(Score: 2) by c0lo on Monday April 13 2015, @03:17AM
Sorry, I like my water rare - blue rare if possible.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by subs on Monday April 13 2015, @11:43AM
I have simplified this topic quite a bit - the details are a lot more complicated - to just focus on the basic energy requirements. Google is your friend if you want the nitty-gritty details. But in short, it boils down to your electricity vs. land cost. If land is cheap, do an evaporation-type process. If electricity is cheap, do RO. As an added bonus, if fossil fuel is cheap, do distillation-type processes (much of the middle east does this).
Or even more advanced. Use solar concentrators to cook water such that it's pushed through an osmosis filter?
I'm not aware of any direct solar-driven process which can produce pressures that would be sufficient for RO *and* be more efficient than electrical pumps (steam engines, while certainly cool, are horribly inefficient).
As you can see [wikipedia.org], both evap-type processes and RO-type processes are fairly similar in energy requirements. My original point was, there's no point in taking RO and then multiplying its energy requirements by ~4-5x by linking it with a solar power plant - i.e. if solar-powered is your goal, just use the sun directly instead of going through an unnecessary, inefficient and expensive electrical conversion step.
Nor any nuclear dirty stuff.
"Dirty" is a very relative word and there are certainly ways to address that (although we have collectively decided not to do anything about it). The beauty about heat-engine power plants is that you can desalinate sorta "for free" just using waste heat from the plant without affecting electrical generation.
(Score: 2) by kaszz on Monday April 13 2015, @12:41PM
Put it simple. If you have one container with sea water connected to an osmosis filter which is connected to an empty container. And then heat the container with water. I think that the steam pressure will force its way to the empty container until pressure equilibrium is achieved.
By repeating this process one should be able to continuously desalinate.
However I have seen a type of desalination which uses a technique which is even better (less energy, less cost) than both evaporation and osmosis. But then I have to dig deeply.
(Score: 3, Insightful) by subs on Monday April 13 2015, @12:52PM
I think that the steam pressure will force its way
If you've already invested enough energy to evaporate water to steam, why not just capture & condense the steam to get distilled (i.e. non-salty) water, instead of then adding an additional lossy step for no reason? The steam *is* your product, salts do not evaporate at 100C.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @04:51AM
Solar cells are fairly cheap AND..... have ever been to West Australia? Space is the least of anyone's issues.
It's literally one big barren desert wasteland almost a third the size of the lower 48 and one city of any size at all and even Perth is under 2 million - and only 2.5 million in total in WA. It's utterly perfect for solar or anything that uses lots of space.
(Score: 0) by Anonymous Coward on Monday April 13 2015, @02:21AM
Or they could just use military weapons they have been developing for over a 100 years for civilian purpose.
Weather control technology has been developed for so long after Tesla did his initial experiments, they must have a plug-in solution by now to modify the weather.
They could just make it rain over the drought-affected area. But this would mean giving this technology to enemies. So the subjects (civilians, who paid for this technology) will have to do without it until the masters change their minds.
(Score: 2) by Phoenix666 on Monday April 13 2015, @10:37AM
I say I do take news of dire water shortages in California with a grain of salt. I recall the last drought in California in the late 80's to early 90's. Driving over the Shasta Lake reservoir on I-5 you could see all that was left was a puddle at the bottom. Yet, as soon as you got to the Bay Area, people were out there, hosing off their sidewalks. Lawn sprinklers were going full blast. Some water shortage!
I haven't seen people in Seattle waste water on a scale as Californians, and Seattle gets rain all the time.
Here are a couple pro tips for the thirsty of California:
Farmers, read up on drip irrigation [wikipedia.org]. The Israelis modernized it in the early 60's. It would be much, much more efficient than the traditional sprayers you still see in the Central Valley.
Residents, ditch your grass lawns and go for xeriscaping [wikipedia.org]. As a bonus, you'll never have to mow the lawn again and you can fire the lawncare service. If you do it right, it can look more attractive than turf. Also, try composting toilets [wikipedia.org], water-saving showerheads [epa.gov], and not hosing off your sidewalk.
Washington DC delenda est.