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I’m surprised this article mentions nothing about energy. Practically all desalination in existence is powered by fossil fuels, with Israel and Saudi Arabia bei

I’m surprised this article mentions nothing about energy. Practically all desalination in existence is powered by fossil fuels, with Israel and Saudi Arabia being the worst offenders. The only reason it’s even economically viable is the externalized cost of carbon emission. It’s simply not a long term tenable solution until this is addressed.

loudmax 8y ago
Carbon emissions is a grave problem with existing desalination infrastructure, but this seems something that can be solved. I'd expect desalination to be well suited for opportunistic use of solar or wind power. Build up reserves of clean water when it's sunny or windy, then deplete those reserves when cheap spare energy isn't available. Of course this goes for new desalination plants. Whether there's political will to convert existing plants to non-fossil fuel sources is another matter. But at least from an engineering perspective there is a way forward. What I get out of the article is that disposing of brine is an ecological hazard. This shouldn't really be a surprise since any engineering effort at large scale is going to have some kind of environmental impact, but this is a new consideration for those of us who don't work in the industry and hadn't thought too deeply about the process.
- beagle3 8y ago
  Most desalination plants around the world are operating at 100% capacity all of the time, because that's what needed to avoid depletion of the reservoirs. To be able to "build up reserves" means that you have to build much higher capacity, but only use as much of it as clean energy allows - in today's world, this is highly uneconomical. If anything, the reserves to be built are energy reserves that allow water to be desalinated continuously -- and that's something which makes sense in general, possibly grid scale as storage technology improves, regardless of the specifics of water desalination.
  - adamcharnock 8y ago
    I’ve heard on the grapevine that facilities are now being designed which work at under 100% capacity in order to soak up excess/cheap power. I believe this is coming about because: 1) the high cost of power and presence of sporadically cheap power makes it economically viable, and 2) designing equipment with lower duty cycles can actually provide substantial cost savings. Ie a facility which only runs 50% of the time is much cheaper to build & run than once which runs 100% of the time. Sorry I cannot cite sources right now.
  - Nasrudith 8y ago
    I believe the reason for that is the expense. They prefer to delay and trying to cut back drastically even when the situation is obviously unsustainable. Thus it gets run at 100% capacity when they finally build it and need three more. To take truly economically fantastic extremes for current technology if desalination was fiscally cheaper than drilling wells we would see them doing that far more.
mcv 8y ago
> Practically all desalination in existence is powered by fossil fuels, with Israel and Saudi Arabia being the worst offenders. Sound like really obvious places to use solar.
- rocqua 8y ago
  Perhaps the issue is that solar farms are more susceptible to sabotage, simply by taking up a much larger area?
Tsubasachan 8y ago
Well the US is currently a net producer of oil and gas. The fracking boom is huge- America has more fossil fuels they know what to do with. Desalination is good for drinking water but its not going to save California's farming though.
foxrob92 8y ago
In Western Australia, a desal plant was built a few years ago [0]. At the same time, a wind farm [1] that offset the power use of the desal plant was built. [0] https://www.watercorporation.com.au/water-supply/our-water-sources/desalination/perth-seawater-desalination-plant https://www.watercorporation.com.au/water-supply/our-water-s... [1] https://en.wikipedia.org/wiki/Emu_Downs_Wind_Farm https://en.wikipedia.org/wiki/Emu_Downs_Wind_Farm

loudmax 8y ago

Carbon emissions is a grave problem with existing desalination infrastructure, but this seems something that can be solved. I'd expect desalination to be well suited for opportunistic use of solar or wind power. Build up reserves of clean water when it's sunny or windy, then deplete those reserves when cheap spare energy isn't available. Of course this goes for new desalination plants. Whether there's political will to convert existing plants to non-fossil fuel sources is another matter. But at least from an engineering perspective there is a way forward. What I get out of the article is that disposing of brine is an ecological hazard. This shouldn't really be a surprise since any engineering effort at large scale is going to have some kind of environmental impact, but this is a new consideration for those of us who don't work in the industry and hadn't thought too deeply about the process.

beagle3 8y ago
Most desalination plants around the world are operating at 100% capacity all of the time, because that's what needed to avoid depletion of the reservoirs. To be able to "build up reserves" means that you have to build much higher capacity, but only use as much of it as clean energy allows - in today's world, this is highly uneconomical. If anything, the reserves to be built are energy reserves that allow water to be desalinated continuously -- and that's something which makes sense in general, possibly grid scale as storage technology improves, regardless of the specifics of water desalination.
- adamcharnock 8y ago
  I’ve heard on the grapevine that facilities are now being designed which work at under 100% capacity in order to soak up excess/cheap power. I believe this is coming about because: 1) the high cost of power and presence of sporadically cheap power makes it economically viable, and 2) designing equipment with lower duty cycles can actually provide substantial cost savings. Ie a facility which only runs 50% of the time is much cheaper to build & run than once which runs 100% of the time. Sorry I cannot cite sources right now.
- Nasrudith 8y ago
  I believe the reason for that is the expense. They prefer to delay and trying to cut back drastically even when the situation is obviously unsustainable. Thus it gets run at 100% capacity when they finally build it and need three more. To take truly economically fantastic extremes for current technology if desalination was fiscally cheaper than drilling wells we would see them doing that far more.

mcv 8y ago

> Practically all desalination in existence is powered by fossil fuels, with Israel and Saudi Arabia being the worst offenders. Sound like really obvious places to use solar.

rocqua 8y ago
Perhaps the issue is that solar farms are more susceptible to sabotage, simply by taking up a much larger area?

Tsubasachan 8y ago

Well the US is currently a net producer of oil and gas. The fracking boom is huge- America has more fossil fuels they know what to do with. Desalination is good for drinking water but its not going to save California's farming though.

foxrob92 8y ago

In Western Australia, a desal plant was built a few years ago [0]. At the same time, a wind farm [1] that offset the power use of the desal plant was built. [0] https://www.watercorporation.com.au/water-supply/our-water-sources/desalination/perth-seawater-desalination-plant https://www.watercorporation.com.au/water-supply/our-water-s... [1] https://en.wikipedia.org/wiki/Emu_Downs_Wind_Farm https://en.wikipedia.org/wiki/Emu_Downs_Wind_Farm