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It isn't technology that holds back water desalination, it is energy availability/cost. Even the most promising desalination tech is only a small efficiency boo

It isn't technology that holds back water desalination, it is energy availability/cost. Even the most promising desalination tech is only a small efficiency boost over simpler established methods. Yeah efficiency gains certain help over the long term, but the overall energy costs are still enormous and nearly require dedicated power plant for any significant amount of clean water. The best bet in actually desalinating population scale levels of water would be investment into nuclear power. And the desalination could double as a buffer for the nuclear plant so that it could be run at peak power and efficiency nearly full time.

julienb_sea 5y ago
This isn't technically accurate, we have access to abundant long term (multi-century) reserves of natural gas which can be used to provide power needed for desalinization. Nuclear is in no way a "blocker". Certainly, cost is a substantial barrier especially in less wealthy nations.
- thewarrior 5y ago
  Carbon emissions
  - julienb_sea 5y ago
    If the choice is reducing emissions or saving lives from dehydration, I wonder which is the appropriate course of action.
    - thewarrior 5y ago
      Which could completely destroy modern civilization over time. Once certain tipping points are crossed most of the earth could become uninhabitable for large parts of the year.
    - azernik 5y ago
      Problem is, carbon emissions make the dehydration worse by heating up the planet. It's counterproductive.
    - pmontra 5y ago
      Probably something else. Gas burns and makes CO2 which increases temperature which increases the likelihood of more dehydration events in future. This is the wrong choice. Actually the long term right choice is not to burn gas anymore. Letting people die is obviously the wrong choice too. When all choices are wrong we must find another choice that can be right. Somebody wrote solar energy, somebody wrote nuclear energy, somebody argued that both are wrong. I don't suggest a solution but I point out that limiting ourselves to binary choices is the wrong way to think.
nradov 5y ago
That's true from an engineering standpoint, but many of the places which are short of fresh water also lack the capital and industrial infrastructure to support large nuclear plants. Solar power seems more realistic from an economic and political standpoint, even if less efficient.
Someone 5y ago
If it’s extremely hot, using solar energy should IMO be the first choice. I don’t find https://en.wikipedia.org/wiki/Solar_desalination https://en.wikipedia.org/wiki/Solar_desalination an easy read, but I think it says using PV to get electricity and that electricity to drive reverse osmosis is one of the best solutions. Certainly, given that solar power is cheaper than nuclear (in the current political climate), nuclear can’t be the better choice for peak loads, which happen when there’s a lot of sunlight.
_ph_ 5y ago
Wouldn't solar be much better for powering desalination than nuclear power? It is way cheaper per energy produced than nuclear, especially in those countries, which need desalination most. Also, it doesn't take a decade to set up. Not even mentioning proliferation issues.
- bin_bash 5y ago
  Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. Nuclear is a great use-case since the problem with nuclear is it needs a constant water source. If you’re desalinating you’ve got that problem covered.
  - stavros 5y ago
    Does nuclear need fresh water? I'd imagine salt water would wreck all the equipment, and you probably don't want to use up all the fresh water you generate...
    - b0tzzzzzzman 5y ago
      You need very pure water for most portions of a nuclear power plan.
      - gruez 5y ago
        that'd depend on the reactor type, no?
      - justshowpost 5y ago
        Not really. Pure heavy water along with pure uranium and pure CANDU reactors are imported components. The quality of cooling water and feed water doesn't matter much. Remember, nuclear power plant is merely a very large heat engine. The main problem is terrorism there.
    - AngryData 5y ago
      The turbines do but you can recycle much if not nearly all of that water by cooling the steam and condensing it, which you could use sea water to heat exchange to for it.
azernik 5y ago
There's also a capital investment problem - good equipment is expensive to set up, even leaving aside the operating costs problem. Achievable, yes, but only for the rich for now. eg Gulf Arab states and Israel are early adopters, the latter with some EU subsidies to defuse water rights as an point of conflict in the Jordan watershed.
amluto 5y ago
I have never believed this. The energy cost of operating a modern (or even moderately old) desalination plant is far, far lower than the cost of water in the Bay Area. It’s not even close. Capital and permitting costs presumably dominate.
Metacelsus 5y ago
What about osmotic pumps? https://science.sciencemag.org/content/183/4121/157 https://science.sciencemag.org/content/183/4121/157
cma 5y ago
> The best bet in actually desalinating population scale levels of water would be investment into nuclear power. FWIW on several occasions we came lose to losing the North American Great Lakes to nuclear accidents, the second largest freshwater stores in the world.

julienb_sea 5y ago

This isn't technically accurate, we have access to abundant long term (multi-century) reserves of natural gas which can be used to provide power needed for desalinization. Nuclear is in no way a "blocker". Certainly, cost is a substantial barrier especially in less wealthy nations.

thewarrior 5y ago
Carbon emissions
- julienb_sea 5y ago
  If the choice is reducing emissions or saving lives from dehydration, I wonder which is the appropriate course of action.
  - thewarrior 5y ago
    Which could completely destroy modern civilization over time. Once certain tipping points are crossed most of the earth could become uninhabitable for large parts of the year.
  - azernik 5y ago
    Problem is, carbon emissions make the dehydration worse by heating up the planet. It's counterproductive.
  - pmontra 5y ago
    Probably something else. Gas burns and makes CO2 which increases temperature which increases the likelihood of more dehydration events in future. This is the wrong choice. Actually the long term right choice is not to burn gas anymore. Letting people die is obviously the wrong choice too. When all choices are wrong we must find another choice that can be right. Somebody wrote solar energy, somebody wrote nuclear energy, somebody argued that both are wrong. I don't suggest a solution but I point out that limiting ourselves to binary choices is the wrong way to think.

nradov 5y ago

That's true from an engineering standpoint, but many of the places which are short of fresh water also lack the capital and industrial infrastructure to support large nuclear plants. Solar power seems more realistic from an economic and political standpoint, even if less efficient.

Someone 5y ago

If it’s extremely hot, using solar energy should IMO be the first choice. I don’t find https://en.wikipedia.org/wiki/Solar_desalination https://en.wikipedia.org/wiki/Solar_desalination an easy read, but I think it says using PV to get electricity and that electricity to drive reverse osmosis is one of the best solutions. Certainly, given that solar power is cheaper than nuclear (in the current political climate), nuclear can’t be the better choice for peak loads, which happen when there’s a lot of sunlight.

_ph_ 5y ago

Wouldn't solar be much better for powering desalination than nuclear power? It is way cheaper per energy produced than nuclear, especially in those countries, which need desalination most. Also, it doesn't take a decade to set up. Not even mentioning proliferation issues.

bin_bash 5y ago
Solar doesn’t provide nearly as much energy and for desalination you need a surprising amount. Nuclear is a great use-case since the problem with nuclear is it needs a constant water source. If you’re desalinating you’ve got that problem covered.
- stavros 5y ago
  Does nuclear need fresh water? I'd imagine salt water would wreck all the equipment, and you probably don't want to use up all the fresh water you generate...
  - b0tzzzzzzman 5y ago
    You need very pure water for most portions of a nuclear power plan.
    - gruez 5y ago
      that'd depend on the reactor type, no?
    - justshowpost 5y ago
      Not really. Pure heavy water along with pure uranium and pure CANDU reactors are imported components. The quality of cooling water and feed water doesn't matter much. Remember, nuclear power plant is merely a very large heat engine. The main problem is terrorism there.
  - AngryData 5y ago
    The turbines do but you can recycle much if not nearly all of that water by cooling the steam and condensing it, which you could use sea water to heat exchange to for it.

azernik 5y ago

There's also a capital investment problem - good equipment is expensive to set up, even leaving aside the operating costs problem. Achievable, yes, but only for the rich for now. eg Gulf Arab states and Israel are early adopters, the latter with some EU subsidies to defuse water rights as an point of conflict in the Jordan watershed.

amluto 5y ago

I have never believed this. The energy cost of operating a modern (or even moderately old) desalination plant is far, far lower than the cost of water in the Bay Area. It’s not even close. Capital and permitting costs presumably dominate.

Metacelsus 5y ago

What about osmotic pumps? https://science.sciencemag.org/content/183/4121/157 https://science.sciencemag.org/content/183/4121/157

cma 5y ago

> The best bet in actually desalinating population scale levels of water would be investment into nuclear power. FWIW on several occasions we came lose to losing the North American Great Lakes to nuclear accidents, the second largest freshwater stores in the world.