7 ms·

China Turns to the Sea for Fresh Water

45 points by Sami_Lehtinen 12y ago

lnlyplnt 12y ago
Israel (obv a different scale than china) has recently also experienced a big push toward desal. What's interesting is there's a moore's law type of effect at play here, desal keeps getting cheaper and cheaper to the point where it's actually a practical alternative to ground water, filtering etc. I think water will be another great Malthusian disappointment, ocean water is basically unlimited (correct me if I'm mistaken), and on a 20-50 year time horizon it seems that the world should be able to alleviate all water scarcity by tapping it.
- mayneack 12y ago
  I suppose it depends on how hard it is to pump it uphill once it's out of the ground given that it starts at sea-level. Some of the more inland places or more uphill places might still be hard to get to with efficient desalination. Eg: Nevada
- kiba 12y ago
  What will you do with the salts and various impurities?
  - jessriedel 12y ago
    Put it back in the ocean.
    - ryannevius 12y ago
      No...Most ocean life is ridiculously dependent on perfect salinity levels. We wouldn't be doing any favors by increasing these levels, no matter how small our impact may be.
      - jessriedel 12y ago
        The change in salinity would obviously be negligible averaged over the ocean, and would be massively, massively dwarfed by other human factors. Your extreme use of the precautionary principle would prohibit essentially all new constructions, if applied widely. Much more interesting is the question of the impact to the nearby ecology in the immediate neighborhood of the discharge pipe. I'm not familiar with this, but I'd wager it can easily be mitigated. EDIT: Thank you to CHY872, who provides a link below to a review of the environmental impact of the waste water from desalinization: > In most other cases environmental effects appear to be limited to within 10s of meters of outfalls.
        CHY872 12y ago
        http://www.ncbi.nlm.nih.gov/pubmed/20633919 http://www.ncbi.nlm.nih.gov/pubmed/20633919 suggests that they can be mitigated.
      - singlow 12y ago
        won't the new fresh water get back to the ocean too?
        jacquesm 12y ago
        There will be a phase lag and a concentration effect.
      - lotsofmangos 12y ago
        Add it to a large tidal river mouth and you just shift the mix point upstream slightly.
  - derekp7 12y ago
    Dump it on the roads in the North during the winter. Or, more seriously, if it is salt that was extracted from the sea, there shouldn't be much harm in putting it back. The fresh water that was extracted will end up back in the sea also, so overall there should be no increase in salinity (except locally where the salt is dumped).
    - Mankhool 12y ago
      There are other products that come out of the process with the salt. There is a good example of the Persian Gulf because of the number of installations and the ability to easily measure the increase in salinity and contaminants. http://www.warponline.org/uploads/contents/103-content-9.-Environmental-Approach-and-Influence-of-Red-Tide-to-Desalination-Process-in-the-Middle-East-Region.pdf http://www.warponline.org/uploads/contents/103-content-9.-En...
    - azinman2 12y ago
      Why can't we just eat the salt?
      - maxerickson 12y ago
        A liter of seawater has 35 grams of salts in it (I looked it up: http://en.wikipedia.org/wiki/Seawater http://en.wikipedia.org/wiki/Seawater ). Compare that to the recommended daily intake of several grams of salt. It's also the case that most of the desalination methods produce concentrated brine instead of dry, clean salt (so extracting the salt would require further energy), but not needing that much of it is the bigger reason.
        azinman2 12y ago
        I didn't mean to drink it, I meant to turn it into table salt. Seems like there ought to be some kind of further usage of it.. industrial or otherwise.
        maxerickson 12y ago
  - IkmoIkmo 12y ago
    Considering drinking water is some tiny, tiny fraction of the world's water, it's probably not going to be a crazy idea to just dump the salt etc back in the oceans where it came from without causing any crazy imbalance, because we're talking about less than 1% of water. About 2.5% of all the world's water is fresh water, and of that about 65% is in glaciers and icecaps. The roughly 0.8% of the world's water that remains, another 65% or so is permafrost and ice, only about 0.5% of the 65% of the 2.5% of the world's water is in river's for example. See for example: http://water.usgs.gov/edu/pictures/watercyclekids/worlds-water-globe-kids-screen.jpg http://water.usgs.gov/edu/pictures/watercyclekids/worlds-wat... So the notion of taking a small fraction of the ocean, desalinating it, and dumping the rest back in the ocean (as will eventually the water itself, later on in the process) probably isn't a big deal. But then it's just inference, I'm not intimate with the subject. Biggest hurdle for me was always that desal was crazily energy intensive. I can't imagine it's become orders of magnitude more efficient, and as energy costs didn't plummet on such a scale (orders of magnitude), I thought it'd still be. But it turns out the costs are dropping fast. I mean, I can easily see desal working for drinking water & cooking (few litres a day) for everyone on earth, but things like agriculture are a whole different beast. A kilo of wheat for example averages over 1.000 litres of water, while meat can go all the way up to 20.000 litres. I can't imagine desal for the billions of farm animals we slaughter every year (yes, billions :-/) , each weighing tens if not hundreds of kilos, for example, or even just agricultural production. I'd be happy to be enlightened!
    - banachtarski 12y ago
      This is emphatically not true. The salinated impurities that are a byproduct of this process will kill everything in the zone that is is reintroduced to. Just because it is a small fraction of the ocean doesn't mean we can easily spread it across the entire ocean. Even then, we are doing an irreversible transformation of the ocean as a whole, and we need to be smart about the waste for the process to be sustainable. I can think of several countries that did this incorrectly and killed large portions of their coastal ecology as a result.
      - mattmanser 12y ago
  - ChuckMcM 12y ago
    Many desalination plants mix it back into the ocean, you pump more water than you are desalinating and the 'waste water' is a mixed brine at an acceptable salinity level. That said with global warming melting a bunch of fresh water glaciers into the ocean, one of the side effects is lowering the salinity level. This suggests to me that boosting it slightly by desal efforts will be negligible at worst, and remediation at best. And of course the quantities we're talking about are pretty much mouse nuts with respect to the entire ocean. But an interesting question to play with is when does a 'keystone pipeline for water' make sense? Clearly Boston would have not minded shipping snow to California to get rid of it this winter. China is working to reroute major water ways, could we manage flood levels on the Mississippi that way? I don't know but it is fun to imagine.
    - chr1 12y ago
      > That said with global warming melting a bunch of fresh water glaciers into the ocean That's a very good point! Potentially desalination could help fixing problems of rising see levels too. There are many deserts that could become huge lakes (in Sahara, Persia, China) and eventually it should be possible to move enough water from sea to compensate for some of polar ice melt.
  - lotsofmangos 12y ago
    Less mining.
- minthd 12y ago
  Looking at price trends of desalination and solar power leads to the conclusion that by 2050, the 100km coastal region everywhere could have access to affordable water, and by 2040 in the western world[1]. Personally i think that water consumption will greatly decrease in the future, because of the great water saving potential of synthetic biology as a way for growing food: In theory using synthetic biology and making basic food components[amino acids, fats, flavourants, etc] can make all the food the world eat, at a land size of rhode island with something like 1/1000 less water than today, generating around 1% of greenhouses gases , and at something between 5-20 cents/pound.And molecular gastronomy and food science know, or are rapidly learning,how to make it into tasty food. As an example for that, there's a company(prottero) that uses synthetic biology, and already making sugar at 5 cents/pound - 1/2-1/3 of the cost of regular sugar, with 30x the land efficiency. So yes, i think Malthusians will be very disappointed. [1]http://www.syngentafoundation.org/db/1/1299.pdf http://www.syngentafoundation.org/db/1/1299.pdf
pmorici 12y ago
Maybe they can export their excess freshwater in giant tankers to CA to solve their drought problem. They already produce most of the electronics we consume.
- dalke 12y ago
  If that were reasonable then we would tank water in from Alaska. Or China would buy AK water. If you want to dream big, in the 1980s there were pipe dreams of bringing in water from the Copper or the Stikine through a large off-shore pipeline to California.
  - maxerickson 12y ago
    There have been serious proposals to ship Great Lakes water to Asia. This article mentions one: http://www.wbez.org/frontandcenter/2011-06-21/great-lakes-face-increasing-pressure-water-world-own-backyard-88159 http://www.wbez.org/frontandcenter/2011-06-21/great-lakes-fa... There is now an agreement placing tight limits on what happens to the water: http://en.wikipedia.org/wiki/Great_Lakes%E2%80%93Saint_Lawrence_River_Basin_Sustainable_Water_Resources_Agreement http://en.wikipedia.org/wiki/Great_Lakes%E2%80%93Saint_Lawre...
    - dalke 12y ago
      There's serious and then there's serious. Fiji exports water to the US. I've heard of a bagel company in London which imports its water from New York City. People buy ice that comes from Alaskan glaciers. (Minor note: If you use under 20 tons/year of tidewater glacier ice then you don't need a permit.) So people are willing to pay a lot of money for provenance. Fiji Water is a good comparison. According to its Wikipedia page, it was exporting over 15 million liters/month. According to others, it was a least 3.5 million liters per month. According to http://www.alternet.org/story/101207/the_true_price_of_fiji_water http://www.alternet.org/story/101207/the_true_price_of_fiji_... it was 130 million liters in a year. I'll say it was 5 million L/month or 60 million L/year. According to the Wikipedia page for "Water export", the Great Lakes -> Asia deal was for 600 million liters, or about 10x of what a single well in Fiji can provide. Oil shipping costs something like $1.20/barrel from Qatar to Rotterdam, says https://books.google.com/books?id=cUHAAgAAQBAJ&pg=PA232&lpg=PA232&dq=supertanker+cost+per+barrel&source=bl&ots=wujrW689cS&sig=XSED9PyMmfzcxmwxP0JKv3g-xWw&hl=sv&sa=X&ei=C7UqVeWCFoLmyQPvxoCQAg&ved=0CB8Q6AEwADgK#v=onepage&q=supertanker%20cost%20per%20barrel&f=false https://books.google.com/books?id=cUHAAgAAQBAJ&pg=PA232&lpg=... . A barrel is 120 liters, or 1 cent per liter shipping costs. That's about $12 thousand per acre-foot. The price of desal water is under $3,000 an acre-foot. If the goal was to market provenance - the Fiji Water of Asia - then it might be profitable. It otherwise doesn't seem like a serious proposal. If there were a were serious need, then I would expect to see water exports from Alaska, which allows bulk water exports (again, according to the "Water export" page at Wikipedia) and is a lot closer to Asia. Since there isn't, I have difficulties understanding how there's a serious proposal.
jarito 12y ago
Why not look at something like nuclear? Since the need is both electricity and heat, a nuclear reactor seems ideal since you don't have to convert power back in to heat - you can just use it directly. With modern recycling techniques and reactor designs the chance of meltdown and wastes are limited, but that seems better than more coal. Not an expert on reactor design vs desal design by any means - would love an opinion on the challenges here outside the standard nuclear ones.
- mmoche 12y ago
  Agreed. Particularly for California which has heavy energy and water needs, nuclear desalination seems like the most future-proof approach, particularly considering the dramatic decrease in aquifer volume as groundwater is extracted to make up for drought-level rainfall.
  - hyperbovine 12y ago
    This seems to be a common fallacy: desal, which is being considered by a few wealthy urban water districts on the coast, will do absolutely nothing to alleviate overpumping by farmers in the Central Valley.
    - mmoche 12y ago
      I think the goal would be to scale desalination efforts to the point where it can replace groundwater pumping statewide. This would come at a huge cost, sure, but once the groundwater runs out, the economics won't look so bad.
      - hyperbovine 12y ago
        The largest desal plant I am aware of is in Saudi Arabia and produces about 830 acre-feet of water a day. Irrigation Central Valley averages 110,000 acre-feet a day, although there are significant seasonal differences. Let's (generously) pretend that you somehow had space in coastal California (not exactly something we have a lot of here, and certainly not cheaply) to build ~60 desalination plants, each double the size of the largest plant in existence. Let's completely ignore the multiple gigawatts of additional power you'd need to run these things. Let's pretend that you somehow convinced the Coastal Commission, EPA, DFG, Fish and Wildlife Service, and all the other relevant entities that intake and discharge from several dozen huge new desal plants dotting the coastline would not significantly impact the marine environment. (Ha.) Assuming all that were true, you would still need to pump roughly 40 million acre feet of water a year from the coast, towards the foothills, in the complete opposite direction which nature intended. Never. Going. To. Happen. Sorry to rain on your parade, but this blind, frequently uninformed faith that Technology will save us from anything and everything just gets annoying after a while.
msoad 12y ago
California has big plans for desalination too http://www.mercurynews.com/science/ci_25859513/nations-largest-ocean-desalination-plant-goes-up-near http://www.mercurynews.com/science/ci_25859513/nations-large...
Someone 12y ago
"the facility will remove salt from 120,000 tons of seawater each day. The result will be 50,000 tons of potable water" Huh? What happens to the other 70,000 tons of water? Or do they mean it will take in 120,000 tons, use something (e.g. distillation, filtering) to move almost all the salt in it to about half of it, and get 50,000 tons of potable water and 70,000 tons of about twice as salty as the input water?
- undersuit 12y ago
  You are correct. The energy cost to desalinate increases as the salt content increases, eventually you have to let it go.
adinb 12y ago
How crazy would it be to (Mostly to help the American Southwest, though if it worked, it could be used anywhere that uses river basins as a major source of freshwater for extremely large areas) create a large pipeline to feed an inland desal plant that's located along the shortest, lowest, least populated path to the headwaters of multiple major freshwater sources, like the Colorado and Rio Grande and the pump desal water into the existing water distribution network? While it's a major geoengineering project (musk-scale!), it would allow for usage of current legal and physical water distribution to be reused. Also, while CA desal cites briny outflow disposal as a major impediment to desal, why not pump the outflow to existing salt flats? (Edited for clarity)
thomabs 12y ago
Desalination uses TONS of electricity. Where does that electricity come from? Fossil fuels. So this "solution" to water shortage actually increases global warming, which will worsen water shortages. And what happens with all the extracted salt? You guessed it - it goes right back, increasing the salinity of the oceans. Ah, humans. But hey, technology solves all problems, right YC?
pm90 12y ago
This has been mentioned elsewhere, but I wonder if we could use the super large tankers that are currently being built for transporting oil and gas for transporting water instead? There is tons of fresh water in the great lakes and the polar ice caps. These ships don't need all the advanced machinery that they currently have for making sure there is no leaks: if there are minor leaks, its water anyways. So its likely to be much cheaper. I'm concerned about the amount of fossil fuels they would consume though.
- azinman2 12y ago
  Is it enough? I'd imagine the amount of water used (industrial, residential, agricultural) is far greater than oil. For example -- ~3k gallons water / lb of beef. That means growing a cow uses A LOT more than the cost of transporting that beef once it's slaughtered.
- mrb 12y ago
  Wouldn't be worth it. The largest super tankers have a deadweight tonnage of approximately half a million tons, which is worth ~$500MM of crude oil. But water is super cheap by comparison. Assuming $0.0015/L (which is what I pay for my tap water in California), half a million tons of water is worth only $750k. Another way to see it: the transport cost per super tanker is about $0.02 per gallon [1] but tap water is ~$0.006 per gallon (again, my tap water cost). So you would be tripling its cost to transport it by sea... [1] http://en.wikipedia.org/wiki/Oil_tanker http://en.wikipedia.org/wiki/Oil_tanker

45 points by Sami_Lehtinen 12y ago

Israel (obv a different scale than china) has recently also experienced a big push toward desal. What's interesting is there's a moore's law type of effect at play here, desal keeps getting cheaper and cheaper to the point where it's actually a practical alternative to ground water, filtering etc. I think water will be another great Malthusian disappointment, ocean water is basically unlimited (correct me if I'm mistaken), and on a 20-50 year time horizon it seems that the world should be able to alleviate all water scarcity by tapping it.

mayneack 12y ago
I suppose it depends on how hard it is to pump it uphill once it's out of the ground given that it starts at sea-level. Some of the more inland places or more uphill places might still be hard to get to with efficient desalination. Eg: Nevada
kiba 12y ago
What will you do with the salts and various impurities?
- jessriedel 12y ago
  Put it back in the ocean.
  - ryannevius 12y ago
    No...Most ocean life is ridiculously dependent on perfect salinity levels. We wouldn't be doing any favors by increasing these levels, no matter how small our impact may be.
    - jessriedel 12y ago
      The change in salinity would obviously be negligible averaged over the ocean, and would be massively, massively dwarfed by other human factors. Your extreme use of the precautionary principle would prohibit essentially all new constructions, if applied widely. Much more interesting is the question of the impact to the nearby ecology in the immediate neighborhood of the discharge pipe. I'm not familiar with this, but I'd wager it can easily be mitigated. EDIT: Thank you to CHY872, who provides a link below to a review of the environmental impact of the waste water from desalinization: > In most other cases environmental effects appear to be limited to within 10s of meters of outfalls.
      - CHY872 12y ago
        http://www.ncbi.nlm.nih.gov/pubmed/20633919 http://www.ncbi.nlm.nih.gov/pubmed/20633919 suggests that they can be mitigated.
    - singlow 12y ago
      won't the new fresh water get back to the ocean too?
      - jacquesm 12y ago
        There will be a phase lag and a concentration effect.
    - lotsofmangos 12y ago
      Add it to a large tidal river mouth and you just shift the mix point upstream slightly.
- derekp7 12y ago
  Dump it on the roads in the North during the winter. Or, more seriously, if it is salt that was extracted from the sea, there shouldn't be much harm in putting it back. The fresh water that was extracted will end up back in the sea also, so overall there should be no increase in salinity (except locally where the salt is dumped).
  - Mankhool 12y ago
    There are other products that come out of the process with the salt. There is a good example of the Persian Gulf because of the number of installations and the ability to easily measure the increase in salinity and contaminants. http://www.warponline.org/uploads/contents/103-content-9.-Environmental-Approach-and-Influence-of-Red-Tide-to-Desalination-Process-in-the-Middle-East-Region.pdf http://www.warponline.org/uploads/contents/103-content-9.-En...
  - azinman2 12y ago
    Why can't we just eat the salt?
    - maxerickson 12y ago
      A liter of seawater has 35 grams of salts in it (I looked it up: http://en.wikipedia.org/wiki/Seawater http://en.wikipedia.org/wiki/Seawater ). Compare that to the recommended daily intake of several grams of salt. It's also the case that most of the desalination methods produce concentrated brine instead of dry, clean salt (so extracting the salt would require further energy), but not needing that much of it is the bigger reason.
      - azinman2 12y ago
        I didn't mean to drink it, I meant to turn it into table salt. Seems like there ought to be some kind of further usage of it.. industrial or otherwise.
        maxerickson 12y ago
- IkmoIkmo 12y ago
  Considering drinking water is some tiny, tiny fraction of the world's water, it's probably not going to be a crazy idea to just dump the salt etc back in the oceans where it came from without causing any crazy imbalance, because we're talking about less than 1% of water. About 2.5% of all the world's water is fresh water, and of that about 65% is in glaciers and icecaps. The roughly 0.8% of the world's water that remains, another 65% or so is permafrost and ice, only about 0.5% of the 65% of the 2.5% of the world's water is in river's for example. See for example: http://water.usgs.gov/edu/pictures/watercyclekids/worlds-water-globe-kids-screen.jpg http://water.usgs.gov/edu/pictures/watercyclekids/worlds-wat... So the notion of taking a small fraction of the ocean, desalinating it, and dumping the rest back in the ocean (as will eventually the water itself, later on in the process) probably isn't a big deal. But then it's just inference, I'm not intimate with the subject. Biggest hurdle for me was always that desal was crazily energy intensive. I can't imagine it's become orders of magnitude more efficient, and as energy costs didn't plummet on such a scale (orders of magnitude), I thought it'd still be. But it turns out the costs are dropping fast. I mean, I can easily see desal working for drinking water & cooking (few litres a day) for everyone on earth, but things like agriculture are a whole different beast. A kilo of wheat for example averages over 1.000 litres of water, while meat can go all the way up to 20.000 litres. I can't imagine desal for the billions of farm animals we slaughter every year (yes, billions :-/) , each weighing tens if not hundreds of kilos, for example, or even just agricultural production. I'd be happy to be enlightened!
  - banachtarski 12y ago
    This is emphatically not true. The salinated impurities that are a byproduct of this process will kill everything in the zone that is is reintroduced to. Just because it is a small fraction of the ocean doesn't mean we can easily spread it across the entire ocean. Even then, we are doing an irreversible transformation of the ocean as a whole, and we need to be smart about the waste for the process to be sustainable. I can think of several countries that did this incorrectly and killed large portions of their coastal ecology as a result.
    - mattmanser 12y ago
- ChuckMcM 12y ago
  Many desalination plants mix it back into the ocean, you pump more water than you are desalinating and the 'waste water' is a mixed brine at an acceptable salinity level. That said with global warming melting a bunch of fresh water glaciers into the ocean, one of the side effects is lowering the salinity level. This suggests to me that boosting it slightly by desal efforts will be negligible at worst, and remediation at best. And of course the quantities we're talking about are pretty much mouse nuts with respect to the entire ocean. But an interesting question to play with is when does a 'keystone pipeline for water' make sense? Clearly Boston would have not minded shipping snow to California to get rid of it this winter. China is working to reroute major water ways, could we manage flood levels on the Mississippi that way? I don't know but it is fun to imagine.
  - chr1 12y ago
    > That said with global warming melting a bunch of fresh water glaciers into the ocean That's a very good point! Potentially desalination could help fixing problems of rising see levels too. There are many deserts that could become huge lakes (in Sahara, Persia, China) and eventually it should be possible to move enough water from sea to compensate for some of polar ice melt.
- lotsofmangos 12y ago
  Less mining.
minthd 12y ago
Looking at price trends of desalination and solar power leads to the conclusion that by 2050, the 100km coastal region everywhere could have access to affordable water, and by 2040 in the western world[1]. Personally i think that water consumption will greatly decrease in the future, because of the great water saving potential of synthetic biology as a way for growing food: In theory using synthetic biology and making basic food components[amino acids, fats, flavourants, etc] can make all the food the world eat, at a land size of rhode island with something like 1/1000 less water than today, generating around 1% of greenhouses gases , and at something between 5-20 cents/pound.And molecular gastronomy and food science know, or are rapidly learning,how to make it into tasty food. As an example for that, there's a company(prottero) that uses synthetic biology, and already making sugar at 5 cents/pound - 1/2-1/3 of the cost of regular sugar, with 30x the land efficiency. So yes, i think Malthusians will be very disappointed. [1]http://www.syngentafoundation.org/db/1/1299.pdf http://www.syngentafoundation.org/db/1/1299.pdf

pmorici 12y ago

Maybe they can export their excess freshwater in giant tankers to CA to solve their drought problem. They already produce most of the electronics we consume.

dalke 12y ago
If that were reasonable then we would tank water in from Alaska. Or China would buy AK water. If you want to dream big, in the 1980s there were pipe dreams of bringing in water from the Copper or the Stikine through a large off-shore pipeline to California.
- maxerickson 12y ago
  There have been serious proposals to ship Great Lakes water to Asia. This article mentions one: http://www.wbez.org/frontandcenter/2011-06-21/great-lakes-face-increasing-pressure-water-world-own-backyard-88159 http://www.wbez.org/frontandcenter/2011-06-21/great-lakes-fa... There is now an agreement placing tight limits on what happens to the water: http://en.wikipedia.org/wiki/Great_Lakes%E2%80%93Saint_Lawrence_River_Basin_Sustainable_Water_Resources_Agreement http://en.wikipedia.org/wiki/Great_Lakes%E2%80%93Saint_Lawre...
  - dalke 12y ago
    There's serious and then there's serious. Fiji exports water to the US. I've heard of a bagel company in London which imports its water from New York City. People buy ice that comes from Alaskan glaciers. (Minor note: If you use under 20 tons/year of tidewater glacier ice then you don't need a permit.) So people are willing to pay a lot of money for provenance. Fiji Water is a good comparison. According to its Wikipedia page, it was exporting over 15 million liters/month. According to others, it was a least 3.5 million liters per month. According to http://www.alternet.org/story/101207/the_true_price_of_fiji_water http://www.alternet.org/story/101207/the_true_price_of_fiji_... it was 130 million liters in a year. I'll say it was 5 million L/month or 60 million L/year. According to the Wikipedia page for "Water export", the Great Lakes -> Asia deal was for 600 million liters, or about 10x of what a single well in Fiji can provide. Oil shipping costs something like $1.20/barrel from Qatar to Rotterdam, says https://books.google.com/books?id=cUHAAgAAQBAJ&pg=PA232&lpg=PA232&dq=supertanker+cost+per+barrel&source=bl&ots=wujrW689cS&sig=XSED9PyMmfzcxmwxP0JKv3g-xWw&hl=sv&sa=X&ei=C7UqVeWCFoLmyQPvxoCQAg&ved=0CB8Q6AEwADgK#v=onepage&q=supertanker%20cost%20per%20barrel&f=false https://books.google.com/books?id=cUHAAgAAQBAJ&pg=PA232&lpg=... . A barrel is 120 liters, or 1 cent per liter shipping costs. That's about $12 thousand per acre-foot. The price of desal water is under $3,000 an acre-foot. If the goal was to market provenance - the Fiji Water of Asia - then it might be profitable. It otherwise doesn't seem like a serious proposal. If there were a were serious need, then I would expect to see water exports from Alaska, which allows bulk water exports (again, according to the "Water export" page at Wikipedia) and is a lot closer to Asia. Since there isn't, I have difficulties understanding how there's a serious proposal.

jarito 12y ago

Why not look at something like nuclear? Since the need is both electricity and heat, a nuclear reactor seems ideal since you don't have to convert power back in to heat - you can just use it directly. With modern recycling techniques and reactor designs the chance of meltdown and wastes are limited, but that seems better than more coal. Not an expert on reactor design vs desal design by any means - would love an opinion on the challenges here outside the standard nuclear ones.

mmoche 12y ago
Agreed. Particularly for California which has heavy energy and water needs, nuclear desalination seems like the most future-proof approach, particularly considering the dramatic decrease in aquifer volume as groundwater is extracted to make up for drought-level rainfall.
- hyperbovine 12y ago
  This seems to be a common fallacy: desal, which is being considered by a few wealthy urban water districts on the coast, will do absolutely nothing to alleviate overpumping by farmers in the Central Valley.
  - mmoche 12y ago
    I think the goal would be to scale desalination efforts to the point where it can replace groundwater pumping statewide. This would come at a huge cost, sure, but once the groundwater runs out, the economics won't look so bad.
    - hyperbovine 12y ago
      The largest desal plant I am aware of is in Saudi Arabia and produces about 830 acre-feet of water a day. Irrigation Central Valley averages 110,000 acre-feet a day, although there are significant seasonal differences. Let's (generously) pretend that you somehow had space in coastal California (not exactly something we have a lot of here, and certainly not cheaply) to build ~60 desalination plants, each double the size of the largest plant in existence. Let's completely ignore the multiple gigawatts of additional power you'd need to run these things. Let's pretend that you somehow convinced the Coastal Commission, EPA, DFG, Fish and Wildlife Service, and all the other relevant entities that intake and discharge from several dozen huge new desal plants dotting the coastline would not significantly impact the marine environment. (Ha.) Assuming all that were true, you would still need to pump roughly 40 million acre feet of water a year from the coast, towards the foothills, in the complete opposite direction which nature intended. Never. Going. To. Happen. Sorry to rain on your parade, but this blind, frequently uninformed faith that Technology will save us from anything and everything just gets annoying after a while.

msoad 12y ago

California has big plans for desalination too http://www.mercurynews.com/science/ci_25859513/nations-largest-ocean-desalination-plant-goes-up-near http://www.mercurynews.com/science/ci_25859513/nations-large...

Someone 12y ago

"the facility will remove salt from 120,000 tons of seawater each day. The result will be 50,000 tons of potable water" Huh? What happens to the other 70,000 tons of water? Or do they mean it will take in 120,000 tons, use something (e.g. distillation, filtering) to move almost all the salt in it to about half of it, and get 50,000 tons of potable water and 70,000 tons of about twice as salty as the input water?

undersuit 12y ago
You are correct. The energy cost to desalinate increases as the salt content increases, eventually you have to let it go.

adinb 12y ago

How crazy would it be to (Mostly to help the American Southwest, though if it worked, it could be used anywhere that uses river basins as a major source of freshwater for extremely large areas) create a large pipeline to feed an inland desal plant that's located along the shortest, lowest, least populated path to the headwaters of multiple major freshwater sources, like the Colorado and Rio Grande and the pump desal water into the existing water distribution network? While it's a major geoengineering project (musk-scale!), it would allow for usage of current legal and physical water distribution to be reused. Also, while CA desal cites briny outflow disposal as a major impediment to desal, why not pump the outflow to existing salt flats? (Edited for clarity)

thomabs 12y ago

Desalination uses TONS of electricity. Where does that electricity come from? Fossil fuels. So this "solution" to water shortage actually increases global warming, which will worsen water shortages. And what happens with all the extracted salt? You guessed it - it goes right back, increasing the salinity of the oceans. Ah, humans. But hey, technology solves all problems, right YC?

pm90 12y ago

This has been mentioned elsewhere, but I wonder if we could use the super large tankers that are currently being built for transporting oil and gas for transporting water instead? There is tons of fresh water in the great lakes and the polar ice caps. These ships don't need all the advanced machinery that they currently have for making sure there is no leaks: if there are minor leaks, its water anyways. So its likely to be much cheaper. I'm concerned about the amount of fossil fuels they would consume though.

azinman2 12y ago
Is it enough? I'd imagine the amount of water used (industrial, residential, agricultural) is far greater than oil. For example -- ~3k gallons water / lb of beef. That means growing a cow uses A LOT more than the cost of transporting that beef once it's slaughtered.
mrb 12y ago
Wouldn't be worth it. The largest super tankers have a deadweight tonnage of approximately half a million tons, which is worth ~$500MM of crude oil. But water is super cheap by comparison. Assuming $0.0015/L (which is what I pay for my tap water in California), half a million tons of water is worth only $750k. Another way to see it: the transport cost per super tanker is about $0.02 per gallon [1] but tap water is ~$0.006 per gallon (again, my tap water cost). So you would be tripling its cost to transport it by sea... [1] http://en.wikipedia.org/wiki/Oil_tanker http://en.wikipedia.org/wiki/Oil_tanker