[MostlyStable]

I know he inputs some numbers, but I am just supremely skeptical of them. If solar + batteries + RO plants could produce water at a price that made agriculture economically viable, then I just don't see how it wouldn't already be happening. Or at the very least be being proposed more broadly than some random guys blog.

If I understand correctly, it is his plan for extracting value from the brine which represents the biggest unknown/the most need for development, while also being the thing that makes it all make sense. I've never heard of any of the existing worlds desal plants doing this, so either it must be harder than he supposes or else he must think that every single person in charge of a desal plant the world over is an idiot.

Don't get me wrong, I realize that sometimes people miss obvious things. And sometimes, there really is a $100 bill on the ground, despite what the apocryphal economist would have you believe.

But in this case, areas like that are what I need to be convinced of. While it's maybe true, you don't just get to assert it.

As they say "What can be asserted without evidence can be dismissed without evidence".

[danaris]

> If solar + batteries + RO plants could produce water at a price that made agriculture economically viable, then I just don't see how it wouldn't already be happening.

The costs of solar and batteries have been dropping for decades. It's 100% believable that this type of thing has been considered, repeatedly, and discarded as economically infeasible, leading to the major players in the field choosing to ignore it for a while—but that the costs have now dropped enough that the economics work out.

[shermantanktop]

Agree with the skepticism, and furthermore if this were such a killer moneymaker you'd expect multiple commercial efforts in this space already.

But this is California - there may be reasons that are not economic or technical that have prevented anyone from trying to develop or pursue such an idea. The concentrated salt-brine discharge, for example, may be impossible to get environmental approval for at these volumes.

[MostlyStable]

Israel is, I believe, the place in the world that has the most desal, and is actually already using it for ag. I'm not familiar with domestic/development policy in Israel, but I have trouble believing it's as restrictive as the CA. So not only has CA not already done it, but neither has Israel, who, at the very least must have different roadblocks.

The point is, it's not only California (which I agree is pretty anti-development and where this plausibly might be disallowed even if it did make economic sense) that is leaving this supposed $100 bill on the ground.

[bryanlarsen]

Part of it might just be timing. The price of Magnesium and Lithium spiked in 2022; what was not viable prior to 2022 may be viable now.

[sapling-ginger]

Are we using that definition of "world" that somehow excludes any other country outside the western alliance? Saudi Arabia and six other countries have more seawater desalination capacity than Israel.

[MostlyStable]

I put "believe" specifically because I knew I didn't know much on the topic and they were a country I knew used a lot. I was very intentionally signalling my lack of certainty about that sentence. A simple correction rather than an assumption of....whatever the hell it is you are vaguely accusing me of would have been much more helpful.

That being said, thanks for the heads up! However, it really just strengthens my point that even more countries are using desal and not mining the brine.

[VintageCool]

The cost of solar dropped by 90% between 2010 and 2020, and the cost of panels fell by 14% last year. Batteries were just straight up not a thing until 2019: California's grid-scale battery storage capacity has been doubling every year since then.

Putting together the solar panels, the battery, the desalination plant, and the brine plant, he's proposing a $42 billion dollar project that has only been economically feasible for a year or two now. I'm not surprised that it hasn't been built yet.

[obblekk]

Places with the saltwater don't want to build large pipelines to send it to places without.

The places without are so dry they cannot drill, condense or truck in salt water, even though they have plenty of solar.

That's a coordination problem with public rights of way issues which is why it wouldn't happen without specific government policy.

[MostlyStable]

You realize that desal is already being used in various places in the world, including for (secondarily) ag, right? So there are already places producing the brine. Why aren't they mining it for value? As far as I'm aware, it is universally being discharged.

So either it's harder to extract value from it than this person supposes or no one else has ever thought to try and get value from it.

The second one isn't impossible but I'm not just going to believe it with no evidence.

[theossuary]

I think the biggest thing this new wave of water desalinization evangelists are latching onto is tightly integrating green energy sources into the process to effectively offset the energy costs (economically and ecologically). But honestly I can't tell if it's really a new generation of designs that'll make desalinization feasible where it currently isn't, or just another example of green washing.

For the basics, practical engineering did a good video on desalinization: https://youtu.be/mxqOPdEUNTs