• Clinicallydepressedpoochie@lemmy.worldOP
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    1 month ago

    I think these are valid arguments but I also think you’ve dismissed one key point by simply saying it’s too expensive. That is, pumping fresh water back upstream. If you were to properly consider the problem the actual cost would be determined by cost per distance traveled and you essentially decide the distance by which ever you are budgeted for. If it’s not feasible to pump back to a usable hydroelelectric dam, pump it up into tower reservoirs.

    I never specified that California would be the best place to implement this process. Hopefully, as solar becomes more widely adopted, these areas could be decided by idea conditions. Also, subsequent solar grids could be tied in to pump the water even further upstream, as solar adoption becomes more popular.

    • hendrik@palaver.p3x.de
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      1 month ago

      I suppose the question is, what does a bucket of water cost if it comes from the groundwater or the next mountains/lake and what does it cost if it comes from a multi-million desalination facility… I mean even if the energy is free (which it’s not) the whole plant has to be built, staffed and maintained. And having an expensive factory sit around idle during the night and peak power and just operational from 10am to 3pm isn’t economical and makes the water that comes out of it even more expensive. And regular water is cheap. Even after being carried around by trucks in the worst case.

      If it’s too expensive compared to normal water, no-one is going to buy it. And the millions of dollars invested in the desalination plant won’t get a return. And then it’s just throwing money out of the window. It could be cheaper to just discard the exess energy than invest millions into something that doesn’t sell. And then you could throw good money after bad and try to subsidize the effort. But I don’t think it’s viable unless it’s a desert or some other geological factors rule out other water sources.

      • Clinicallydepressedpoochie@lemmy.worldOP
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        1 month ago

        In other words, green technology is not feasible from an economic standpoint. Did you factor in the effects of global warming or the cost of depleting known waterways/systems?

        • hendrik@palaver.p3x.de
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          1 month ago

          I mean you also have to factor in the carbon footprint of the concrete that goes into the desalination facory. And producing solar panels also isn’t light on the planet. It’s going to be a complicated equation. But large factories like desalination plants plus the energy also don’t come without consequence for the planet. Even more so if they’re underutilized. I’m not sure if that counts as “green” anymore. The technology is probably neither feasible from an economic standpoint, nor from an ecological one.

            • hendrik@palaver.p3x.de
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              1 month ago

              Sure. I’m not a professor for water treatment. But I haven’t heard any of them advocate for this, so there might be a reason to it. And with the constraint, it has to be powered just by excess solar energy, I’m pretty sure I’m right. That might change if you find cheap regenerative energy that runs the plant 24/7 and there are other geological factors that make alternative water sources less attractive. But there is no way it’ll work like this. And I mean we use lots of water everyday. Not just in the house, but also for farming and whatnot. You’re going to need a massive amount of energy to have a noticeable impact and save other water sources. And solar doesn’t have a particularly good carbon footprint. There are lots of reasons why my estimation might be closer to the truth. (For current technology, of course.) The desalinated water will come with a carbon footprint and a price. And both of them might not be favorable.

    • litchralee@sh.itjust.works
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      1 month ago

      If you were to properly consider the problem the actual cost would be determined by cost per distance traveled and you essentially decide the distance by which ever you are budgeted for.

      I wrote my comment in response to the question, and IMO, I did it justice by listing the various considerations that would arise, in the order which seemed most logical to me. At no point did I believe I was writing a design manual for how to approach such a project.

      There are much smarter people than me with far more sector-specific knowledge to “properly consider the problem” but if you expected a feasibility study from me, then I’m sorry to disappoint. My answer, quite frankly, barely arises to a back-of-the-envelope level, the sort of answer that I could give if asked the same question in an elevator car.

      I never specified that California would be the best place to implement this process.

      While the word California didn’t show up in the question, it’s hard to imagine a “state on the coast” with “excess solar” where desalination would be remotely beneficial. 30 US States have coastlines, but the Great Lakes region and the Eastern Seaboard are already humid and wet, with rivers and tributaries that aren’t exactly in a drought condition. That leaves the three West Coast states, but Oregon and Washington are fairly well-supplied with water in the PNW. That kinda leaves California, unless we’re talking about Mexican states.

      I’m not dissing on the concept of desalination. But the literature for existing desalination plant around the world showcases the numerous challenges beyond just the money. Places like Israel and Saudi Arabia have desalination plants out of necessity, but the operational difficulties are substantial. Regular clogging of inlet pipes by sealife is a regular occurrence, disposal of the brine/salt extracted is ecologically tricky, energy costs, and more. And then to throw pumped hydro into this project would make it a substantial undertaking, as dams of any significant volume are always serious endeavors.

      At this point, I feel the question is approaching pie-in-the-sky levels of applicability, so I’m not sure what else I can say.