7 ms·

A vision for the alleviation of water scarcity in the US Southwest

125 points by boiler_up800 3y ago

deegles 3y ago
Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?
- gorkish 3y ago
  If efficiency is the metric you're going for, move the people and do nothing. It's probably what will happen eventually anyway.
  - missedthecue 3y ago
    Moving 50 million people seems to me to incur more effort than building $10b of solar
    - konschubert 3y ago
      Yea but that wouldn’t be disruptive so it’s no fun /s
  - chmod775 3y ago
    I'm going to go out on a limb and claim there's more than enough water for the people - the area is just unsuitable for the economic activity a small fraction of those people engages in. Move that.
- martythemaniak 3y ago
  It is probably cheaper to do Solar PV due to unit economics rather than overall system efficiency. There's been a lot written on learning curves and wright's law, but rate of improvement is driven by design complexity and need for customization. Concentrating solar is both more complicated and needs more site customization, whereas solar pv modules are simpler and fly out of factories by the millions. This is a wonderful table: https://substackcdn.com/image/fetch/w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa3d198e2-77ec-478b-a595-e39b0b2ba4ba_2516x1784.png https://substackcdn.com/image/fetch/w_1456,c_limit,f_webp,q_... From this post: https://www.volts.wtf/p/which-technologies-get-cheaper-over https://www.volts.wtf/p/which-technologies-get-cheaper-over
hnmullany 3y ago
Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants: "Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora and fauna. This is especially so when the optimal initial high dilution capacity is lacking in the discharge system. Consequently, brine discharge plumes spread over large areas of the sea floor and modify the structure and distribution of benthic communities such as seagrass habitats. ... Rejected brine disposal costs are between 5 and 33% of the whole desalinization process, depending on the characteristics of the brine, its pretreatment level before disposal, disposal method, and volume" from: Jiménez-Arias, D., Morales-Sierra, S., García-Machado, F.J., García-García, A.L., Luis, J.C., Valdés, F., Sandalio, L.M., Hernández-Suárez, M. & Borges, A.A. 2020, "Rejected brine recycling in hydroponic and thermo-solar evaporation systems for leisure and tourist facilities. Changing waste into raw material", Desalination, vol. 496, pp. 114443.
- pfannkuchen 3y ago
  Can’t we pipe the seawater inland and then deposit the salt on land?
  - bell-cot 3y ago
    When it rains, what happens to the run-off from a huge pile of salt?
    - mrguyorama 3y ago
      Surely the massive open air pools of salt used for sea salt production have figured out how this process works. On the Californian coast, there is already at least https://en.wikipedia.org/wiki/South_Bay_Salt_Works https://en.wikipedia.org/wiki/South_Bay_Salt_Works , a sea salt production facility that uses salt pools. They produce 80k tons annually of salt, which means they process 2666k tons of seawater to get that. If that one salt production facility used brine as their source instead of seawater, they would have allowed the facility to produce 2580k tons of freshwater. The "urban" usage of water in California is 10 million acre-feet (ish), so that's not exactly a significant amount.
floatrock 3y ago
So basically pump seawater up from the Gulf of California across the border over a flat floodplain to the Salton Sea (south of joshua tree) and use cheap PV to run desalination plants that will restore one of our biggest environmental disasters https://99percentinvisible.org/episode/sea-worth-salt https://99percentinvisible.org/episode/sea-worth-salt back into a vacation hotspot greater than Palm Springs. Costs of the PV and desal (relatively cheap but still absurdly expensive in absolute terms at this scale) will be offset by real estate development and hand-wavey mineral extraction from the sea water. Environmental impacts of desal's salty waste stream is hand-waved away. I mean, economic math miiight pencil out. But basing the speculative prosperity of an entire region on a bunch of water and energy machines seems... well... fragile? Full of hubris? Seems like a really expensive way of maintaining an otherwise-unsustainable Potemkin vacation village. But then again, that's basically the story of the american southwest, so, /shrug? (see Cadillac Desert and all the water stories out there...)
- deelowe 3y ago
  Isn't that the same story with Vegas? Would it exist without the hoover dam?
  - floatrock 3y ago
    And Los Angeles. And Phoenix. Not saying it doesn't work. Clearly it does, at least for a time or up to a certain level of population (Phoenix is banning new development because it's literally out of water, California is poster-child for water wars). I guess it's something about spending that much effort and human capital to force something so inherently unsustainable that just seems... wasteful? Full of hubris? I don't know, maybe it's just a general sadness that this much ingenuity isn't being spent elsewhere where it could amplify existing natural forces instead of fighting a never-ending battle against entropy for something that doesn't want to exist. Or maybe I'm just an internet sourpuss without enough vision. I just can't shake the "why are we doing this" melancholy about this.
  - tracerbulletx 3y ago
    Yeah it wouldn't be a city but just as a fun fact Las Vegas means "The Meadows" it had a really big aquifer and artesian springs fed by the Spring Mountains. It was sustainable as a town without the dam. Vegas also is allocated a very small portion of the water from Lake Mead, Nevada only gets about 4% of what is taken from it every year, and most of that is for farming still. The city probably needs like 1% to survive.
vondur 3y ago
I would really love to see the Los Angeles basin get its primary water needs met from desalination. This would lessen the need for the LA dept. of Water and Power taking water from the Owens Valley north of the LA area which subsequently turned the valley into a desert.
PaulDavisThe1st 3y ago
The article claims that the plan described could produce 5MAF / year (the entire allocation of Colorado River water for California). There's no explanation I could find of where this water will come from. The Salton Sea itself only holds 1.5MAF. The title also seems a bit grandiose. "The US Southwest" for most people I think extends at least as far as the I25 corridor up through NM and CO, and for some it might even reach into western TX. The plan described would really have very little impact on the overall water situation here, even if it did actually live up to its claim of effectively freeing up CA's Colorado allocation.
- NegativeLatency 3y ago
  Looks like it comes from the Gulf of California in one of the drawings
- bryanlarsen 3y ago
  The second hand drawn map shows the source pumping station at the Sea of Cortez.
bradford 3y ago
NYT daily had a relevant podcast episode on this (https://www.nytimes.com/2023/09/01/podcasts/the-daily/water-supply-arizona.html https://www.nytimes.com/2023/09/01/podcasts/the-daily/water-...?). Discussion centered around using the water for Arizona, not California. (I'm unable to speak of the relative merits of pumping the water from one state to another). General takeaways: Proponents of the solution seemed to understate challenges and risks associated with: 1. The pipeline itself (i.e., where to build it) 2. The disposal of brine solution into the Gulf of California. 3. Cooperation with Mexico. That's not to say the challenges couldn't be addressed, but discussion of such challenges is noticeably absent from the original article.
- photonthug 3y ago
  > 3. Cooperation with Mexico Yeah this seems like a big challenge. Even if the Gulf of California is closer, or if it's all downhill, the requirement for international cooperation seems like it would make this a much more complex option than just using the Pacific. Plus if I were Mexico, I'd honestly be looking at the Salton Sea disaster, noticing that some new plan calls for putting salt down in my neighborhood instead of off the LA or San Diego coast.. sounds sketchy. Meanwhile, the Arizona version of this plan is understandable.. Phoenix is thirsty, they have no coast, it's shorter to get to one in Mexico than California and anyway they might actually have better luck dealing with Mexico than California. But can anyone explain briefly why California would want or need the plan to involve Mexico?
  - JieJie 3y ago
    Maybe this, since it has to do with Colorado River water. https://www.watereducation.org/aquapedia/mexico-and-colorado-river-water https://www.watereducation.org/aquapedia/mexico-and-colorado...
bilsbie 3y ago
Ok this keeps happening. I posted this exact URL 3 days ago. Shouldn’t the same URL submitted again redirect to mine? Is there a certain cutoff when someone else can submit the same URL? (I’m not complaining, I just want to understand what the rules are)
- bell-cot 3y ago
  There's a whole lot of randomness in whether (or not) a submission "makes it" on HN. Re-submission cutoffs, crediting the first submitter, etc. would all require more rules & implementation. We pretty much don't care to bother.
- CharlesW 3y ago
  The kindling of your post didn't catch fire, and this one did. It's not personal. More from @dang: https://news.ycombinator.com/item?id=37126175 https://news.ycombinator.com/item?id=37126175
cs702 3y ago
Wow, what a fantastic post! The author, who holds a PhD from Caltech, proposes taking advantage of the decreasing cost of solar power to enable a new age of clean water abundance in California, sustainably, with the potential for massive revenues and profits at all steps in the value chain. Even if the author's calculations are off by a factor of two, the proposal looks like it could work. At a minimum, it merits serious consideration. The status quo will not solve our pressing environmental problems. The main challenge an innovative large-scale project like this one would face, I think, is a regulatory bureaucracy which to me often seems like it was designed for the technologies and infrastructure of the 20th century, not for those of the 21st century. I shudder to think of, say, inspectors who are highly trained on narrow technical matters, but who lack a fundamental, multi-disciplinary, big-picture view of the entire project, deciding whether to approve individual tiny little parts of it.
- photochemsyn 3y ago
  It's a very interesting idea - but practically speaking, the kind of water volumes needed for drinking and bathing water for a city like Las Vegas are dwarfed by the volumes needed for the farming of sugar beets, alfalfa for dairy, golf course grass maintenance, etc. If current trends in the American Southwest continue, extreme water conservation will have to become the norm (the other alternative being depopulation of the region).
  - digging 3y ago
    Yeah we can't realistically get better water outcomes by only changing out supply. We have to change our usage too. Farms should be converting to crops that have lower water usage, and food manufacturers should be converting to foods that make use of those crops.
- Sharlin 3y ago
  Skepticism is warranted. The track record of "Oh, we don't have to change our incredibly wasteful and unsustainable ways after all, technology will fix things!" has been... poor.
- skywhopper 3y ago
scythe 3y ago
He's doing it wrong. I don't mean some grander point about environmentalism or development, I mean that I have specifically examined solar desalination for the Imperial Valley and he's missed a much simpler way to get the water from point A to point B. See, there's this other basin in nearby Mexico called Laguna de Salada which is basically an empty salt flat about ten meters below sea level. If you flood that by dredging a canal (about 10-20 km and not very high), you only have to transport the desalinated water about five kilometers to get it into the Imperial Valley drainage basin. There's no need to back up the Colorado and mess up what's left of the delta, plus you can put the rejected brine back into the now Golfo de Salada where it will mix more slowly and (hopefully) less destructively with the seawater to the south. The area will still be something of a dead zone, but it would only replace an existing dead zone.
johnohara 3y ago
And then there's the problem of removing all that pesky lithium, 3400 kilotons, enough to support over 375 million electric vehicle batteries, which fortunately, is not very important towards reaching net-zero emissions by 2050. [0] https://www.energy.gov/eere/articles/us-department-energy-analysis-confirms-californias-salton-sea-region-be-rich-domestic https://www.energy.gov/eere/articles/us-department-energy-an...
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joescharf 3y ago
I've been thinking about this as well. As climate change affects the distribution of potable water on the planet, it would seem prudent to start installing solar backed desalination and water pipelines to ensure water security for areas at risk. Now I'm no hydrologist, and haven't researched this idea deeply yet, so don't know second and third order effects (i.e. brine disposal mentioned above, and of course the economics of such a venture.) It seems at some point our collective hands may be forced and we may have to do something that doesn't make a profit, yet sustains humanity as a going concern. Finally, the fact that we haven't "terraformed" in this fashion drought-stricken places like Africa or elsewhere is a pity. But yes, economics, profit, geopolitics, power struggles, I get it.
- rindalir 3y ago
  I am really appreciating the IANAH and TINHA side effects of your post :)
yinser 3y ago
I thought this would be a post from Rain Maker but it is another promising project altogether. If you’re interested check out Augusts Doricko’s company looking to do cloud seeding in the same region https://www.makerain.com/ https://www.makerain.com/
solardev 3y ago
I wonder if this would be cheaper than just paying the water rightsholders not to use the water? If the Salton Sea doesn't have a steady input (from snowpack? not familiar with it), doesn't desal mean we're really just expanding the unsustainable use of the Colorado, maybe delaying it another few decades, but ultimately still growing more and using more water than its watershed can naturally sustain -- especially as climate change increases? I think the fundamental problem here isn't that we need to make more freshwater out of brine, but that the California (and other) water rights are set to levels that cannot realistically be maintained. The law needs to change even if that hurts the grandfathered rightsholders; there just isn't the same amount of water anymore.
connorgutman 3y ago
We desperately need to focus on conservation efforts instead of attempting to engineer "solutions" that only end up encouraging further consumption. Hot take: Maybe the American SouthWest wasn't meant to support > 1/3 of America's agricultural output. Solar desalination of the Salton traps humanity in an energy contract when we could achieve meaningful conservation efforts instantaneously by banning the production of many water-intensive luxury crops. Why is Arizona farming alfalfa for Saudi horses? Why is California producing 2.8 billion pounds of almonds a year? Why is the United States one of the highest consumers of red meat in the world when sustainable plant-based alternatives exist and use a fraction of the water? This regional water crisis (as well as our global climate crisis) cannot be solved without making bold sacrifices to our daily lives. I know this is Hacker News, but not everything can be solved with new/additional technology.
- nozzlegear 3y ago
  > We desperately need to focus on conservation efforts instead of attempting to engineer "solutions" that only end up encouraging further consumption. With respect, why can't we do both?
  - connorgutman 3y ago
    I’m not against using technology but my concern is that we need to treat resource consumption as a form of addiction. Humanity frequently uses technology as an excuse to further consume instead of using it to pay off ecological debt.
- njovin 3y ago
  This is so dead-on it hurts. The "taming" of the rivers in the American west by the Army Corp of Engineers has been romanticized and the underlying motives have been swept under the rug: we prioritized these massive public works projects to provide cheap water to big ag businesses at the cost of sustainability and residential access. IMO we should absolute not be exporting anything farmed with subsidized water while the survivability of just living in the US southwest is uncertain due to current water levels and climate patterns. That seems like the lowest of low-hanging fruit.
alexb_ 3y ago
Just charge people for the natural resources of the country via taxes. Resource and land taxes solve basically every single problem in the current American economy yet people do not want to even think about doing it.
- jakderrida 3y ago
  > yet people do not want to even think about doing it. probably because placing a price on some things seems too transactional. Not saying you're wrong, though. Just saying that's why. The alternative is allowing more rapacious disregard for the aggregate negative effects on everyone as a whole.
- School-Cotton 3y ago
  Plenty of people are thinking about it, including you. The issue is that the American makes it structurally impossible to pass any major reform on any controversial topic.
- justinator 3y ago
  You're right - air's also getting a little too polluted for my taste. Maybe if I could get a hold of some taxed air, I could breath easy! We could put the pollutants back into the untaxed air too!
  - alexb_ 3y ago
    Why are you acting as if this is some fantasy thing? Pollution taxes absolutely are exactly what that is. You're "using up" all the good air!
- shermantanktop 3y ago
  US taxes are already complicated, in large part due to the effort to build incentives and disincentives in the way that you describe. And yet the process to build the existing incentives is inescapably political, and for good reason: if you impose a significant change to taxation, there are winners and losers on day 1. Nobody likes to lose, especially if they feel they are doing nothing wrong. For your specific idea, the red/blue political map shows you who will probably lose.
MostlyStable 3y ago
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".
- shermantanktop 3y ago
  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 3y ago
    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.
amarant 3y ago
Seems to me like atmospheric water generators are a good fit here. That gets rid of the brine problem entirely, and from what I've read it's competitive in terms of energy consumption. https://solarimpulse.com/solutions-explorer/high-efficiency-atmospheric-water-generators https://solarimpulse.com/solutions-explorer/high-efficiency-...
elmolino89 3y ago
I am by no means a desalination expert, but pumping vast amount of a salty water 100+ kilometers (Pacific Coast) or from the Sea of Cortez (closer to 200kms) seems strange as compared to building the desalination plant on the shore and transfer the electricity generated in the desert. One can also replace some drinking or agricultural water used way closer to the coast in CA from the Colorado Basin with the newly desalinated one. Way less pumping. Or do I miss something?
- konschubert 3y ago
  You are right. Power is easier to transport than water.
  - elmolino89 3y ago
    I have spend few years in San Diego doing hikes inland. There are decently sized mountains in the desert between say Borrego Springs and the coast. Not an optimal area to build a pipeline cheaply. Pipe going along Colorado river should have less bumpy course but there is a biosfere reserve just on the top of Baja California. Not a good spot to suck giant volumes of sea water, even less so to construct a pipeline or heavens forbid dump the concentrated brine.
adrianmonk 3y ago
> The solar panels convert wasted sunlight into electricity, one of the most useful forms of energy, at the lowest cost ever in human history. The batteries make this power available at night, enabling 100% utilization of the higher capex systems downstream. The RO desal plant uses this power to strip salt out of fresh water I wonder if you could store the energy as pressure instead of electricity in batteries. From what I gather[1], the biggest energy draw in reverse osmosis is pressurizing the water to force it through the RO filters. So, while the sun is shining, fill a tank halfway with salty water, then use solar energy to run pumps to pressurize air above the water. When the sun isn't shining, you now have pressurized water you can let through the RO filters. Compared to a regular RO plant, this requires high-pressure storage tanks and additional pumps. I'm unsure whether that costs less than batteries or not. Another part of the analysis is that, if you do build the batteries, they can earn extra money with a side gig stabilizing the grid. Occasionally, when grid conditions get very gnarly, you could shut down the RO plant for a few hours and make a quick buck selling your battery power on the market. Alternatively, you could pump the water uphill during the day and let gravity supply the energy to force it through the RO filters at night. This means you'll have to build a special reservoir for pre-treated salty water somewhere, though, and you need a lot of pressure, so it would need to be at a high elevation. --- [1] Source (kind of old): https://www.oas.org/dsd/publications/unit/oea59e/ch20.htm https://www.oas.org/dsd/publications/unit/oea59e/ch20.htm
- amluto 3y ago
  A fundamental challenge with storing pressure is that water is essentially incompressible. This means that you can’t build a 1000 gallon tank and store any useful amount of energy in the form of pressurized water in that tank. Mathematically, it’s easy to forget that the PV term in enthalpy is a mathematical trick, not a physical thing, and that it mostly does a nice job explaining physical things when P = atmospheric pressure. If you want to store, say, 100psi water, the energy you care about is P times delta V, so you need some thing that can change its volume easily, cheaply, and reversibly while under pressure. As a practical matter, this means compressed air or maybe springs. So that water “pressure tank” is actually an air pressure tank that happens to have some water in it too. There’s nothing wrong with storing pressurized air, except that it’s a heck of a lot more dangerous than storing pressurized water due to the fact that it really does have energy stored in it. (There’s a reason that a PVC pipe filled with 80psi water is a common thing in houses and the main danger is that water escapes if it breaks. A pipe full of 80 psi air is quite hazardous.) There are startups that have played with compressed air energy storage. The resulting gizmos are large. I would expect a RO plant that is optimized for intermittent use without any energy storage at all to end up being a viable alternative to energy storage, but maybe batteries will end up being cheap enough that this isn’t worthwhile.
bparsons 3y ago
The details might be a bit goofy, but this sort of large scale geoengineering project is going to be the only way that the SW is going to remain inhabitable. The American southwest has a couple big things going for it -- unlimited sunshine and an extraordinary amount of empty land. You can combine these things to create huge amounts of electricity which can be used to irrigate new farm land, power mines and build new cities. The status quo of drawing down on the increasingly precarious water supply is not feasible though. Before the unprecedented snowpack of 2022/2023, many regions were facing extreme water rationing.
- drkevorkian 3y ago
  Habitable? There is plenty of water for it to be habitable, residential use is a drop in the bucket compared with agricultural use. Without a technological solution, we'll have to scale back agriculture, but that's not a regional problem, since the market for food is an international one.
  - ianburrell 3y ago
    Also, we don't have to get all of the water from desalination. Southern California can use desalination, which makes sense to the ocean, short distances, and solar power. That frees up Colorado River water that Nevada and Arizona can use. Desalination will probably never be worth it from agriculture, but agriculture should survive on the water they can access after people.
thelastgallon 3y ago
If we switch to renewables, there will be plenty of water, which is now used by fossil fuels. U.S. thermoelectric plants are the largest source of U.S. water withdrawals, accounting for more than 40% of total U.S. water withdrawals in 2015.: https://www.eia.gov/todayinenergy/detail.php?id=50698 https://www.eia.gov/todayinenergy/detail.php?id=50698
hnu123 3y ago
There's an abundance of freshwater in the east coast, northwest and midwest. Why not shift some of the exess water from the great lakes, east coast and northwest to southwest? Can't we pipeline the water to giant reservoirs in the sw or even carve extend tributaries from the missouri river or create canals down to the sw? It's not exactly rocket science.
- ianburrell 3y ago
  Way, way too expensive. Pumping water east of the Rockies would use a ton power. Local desalination would cost way less. This plan is not feasible because it pumps water from Sea of Cortez to Salton Sea over 200 mi.
01100011 3y ago
A solution is there if we had the will to implement it: https://www.osti.gov/biblio/963122 https://www.osti.gov/biblio/963122 Take excess water from SE floods and pump it west opportunistically using excess renewables. Bonus because you can use the pumped water as gravity storage. Yes, it is not cheap, energetically, to pump water. Yes, you have to cross a big mountain range(which increases opportunities for gravity storage). For some reason, this suggestion always gets a lot of comments from folks living around the great lakes who think we're going to 'steal' 'their' water(just like they 'steal' CA grown produce, I guess?). Anyway, a national water grid is needed for national food security and can mitigate flooding damage in the SE(probably more important b/c of AGW).
- downut 3y ago
  That report is mainly about the upper Mississipi (Midwest) not the lower, or points east (Southeast). And it is only supposed to run during large scale flood events, which the report cites as lasting ~80 days, worst case? Looking at flood event frequency, this report cites: 1912, 1913, 1927, 1937, 1965, 1973, 1982, 1993, and 2008. So, let's be generous and double the event length to 160 days and double the event frequency to ~20 per century (increasing, to be sure). That's a time utilization of the infrastructure of ~9%, if Ima doing the math right. It is apparently true: water runs uphill toward money. In this case, literally multiple miles of vertical elevation gain to get it to the Navajo Nation. I mean I could see maybe pumping to Denver, or maybe over the continental divide past Denver, but... direct to almost the NM, AZ border? Maybe just start with baby steps and for instance charge those good enterprising folk who farm alfalfa with nearly free water in the AZ desert and ship it to Saudi Arabia.
palmfacehn 3y ago
https://energycentral.com/c/pip/great-mexicali-energy-and-shipping-canal https://energycentral.com/c/pip/great-mexicali-energy-and-sh... Here's an alternative proposal based on a sea level canal and tidal power.
llsf 3y ago
Maybe we should not use so much water (for agriculture) in a desert area at the first place. Feels like we are putting fixes on top of fixes. "A Saudi Arabian company grows alfalfa on farmland in Arizona and California and sends it overseas to feed the country's cows. These legal farming operations extract groundwater in Arizona and water from the Colorado River across the border in California, experts say." source: https://www.maxwell.syr.edu/news/article/koch-discusses-saudi-arabian-farms-using-water-from-arizona-and-california-in-kusa-article https://www.maxwell.syr.edu/news/article/koch-discusses-saud... Maybe if we stop exporting Colorado water packed in alfalfa and other agri-products, we would have enough water ? Exporting water through alfalfa to Saudi Arabia who indeed banned alfalfa fields in their country because it was consuming just too much water, is one of the problem we should fix before installing PV and batteries in the desert, and dump concentrated brine somewhere.
skywhopper 3y ago
Lots of questionable assumptions in this article, but I wanted to call this particular calculation out because it's so blatant: 5 MAF/year of 6% salinity brine contains more than 10 million tonnes of magnesium, comparable to current global production, not to mention other light metals. At spot prices around $5000/T, a mature brine extraction industry could net >$50b/year "Net" means after expenses, so this calculation is assuming that extracting 100% of the magnesium from the brine would have zero cost, not to mention that it also assumes that doubling the world supply of magnesium would have zero impact on its price.

125 points by boiler_up800 3y ago

deegles 3y ago

Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?

gorkish 3y ago
If efficiency is the metric you're going for, move the people and do nothing. It's probably what will happen eventually anyway.
- missedthecue 3y ago
  Moving 50 million people seems to me to incur more effort than building $10b of solar
  - konschubert 3y ago
    Yea but that wouldn’t be disruptive so it’s no fun /s
- chmod775 3y ago
  I'm going to go out on a limb and claim there's more than enough water for the people - the area is just unsuitable for the economic activity a small fraction of those people engages in. Move that.
martythemaniak 3y ago
It is probably cheaper to do Solar PV due to unit economics rather than overall system efficiency. There's been a lot written on learning curves and wright's law, but rate of improvement is driven by design complexity and need for customization. Concentrating solar is both more complicated and needs more site customization, whereas solar pv modules are simpler and fly out of factories by the millions. This is a wonderful table: https://substackcdn.com/image/fetch/w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa3d198e2-77ec-478b-a595-e39b0b2ba4ba_2516x1784.png https://substackcdn.com/image/fetch/w_1456,c_limit,f_webp,q_... From this post: https://www.volts.wtf/p/which-technologies-get-cheaper-over https://www.volts.wtf/p/which-technologies-get-cheaper-over

hnmullany 3y ago

Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants: "Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora and fauna. This is especially so when the optimal initial high dilution capacity is lacking in the discharge system. Consequently, brine discharge plumes spread over large areas of the sea floor and modify the structure and distribution of benthic communities such as seagrass habitats. ... Rejected brine disposal costs are between 5 and 33% of the whole desalinization process, depending on the characteristics of the brine, its pretreatment level before disposal, disposal method, and volume" from: Jiménez-Arias, D., Morales-Sierra, S., García-Machado, F.J., García-García, A.L., Luis, J.C., Valdés, F., Sandalio, L.M., Hernández-Suárez, M. & Borges, A.A. 2020, "Rejected brine recycling in hydroponic and thermo-solar evaporation systems for leisure and tourist facilities. Changing waste into raw material", Desalination, vol. 496, pp. 114443.

pfannkuchen 3y ago
Can’t we pipe the seawater inland and then deposit the salt on land?
- bell-cot 3y ago
  When it rains, what happens to the run-off from a huge pile of salt?
  - mrguyorama 3y ago
    Surely the massive open air pools of salt used for sea salt production have figured out how this process works. On the Californian coast, there is already at least https://en.wikipedia.org/wiki/South_Bay_Salt_Works https://en.wikipedia.org/wiki/South_Bay_Salt_Works , a sea salt production facility that uses salt pools. They produce 80k tons annually of salt, which means they process 2666k tons of seawater to get that. If that one salt production facility used brine as their source instead of seawater, they would have allowed the facility to produce 2580k tons of freshwater. The "urban" usage of water in California is 10 million acre-feet (ish), so that's not exactly a significant amount.

floatrock 3y ago

So basically pump seawater up from the Gulf of California across the border over a flat floodplain to the Salton Sea (south of joshua tree) and use cheap PV to run desalination plants that will restore one of our biggest environmental disasters https://99percentinvisible.org/episode/sea-worth-salt https://99percentinvisible.org/episode/sea-worth-salt back into a vacation hotspot greater than Palm Springs. Costs of the PV and desal (relatively cheap but still absurdly expensive in absolute terms at this scale) will be offset by real estate development and hand-wavey mineral extraction from the sea water. Environmental impacts of desal's salty waste stream is hand-waved away. I mean, economic math miiight pencil out. But basing the speculative prosperity of an entire region on a bunch of water and energy machines seems... well... fragile? Full of hubris? Seems like a really expensive way of maintaining an otherwise-unsustainable Potemkin vacation village. But then again, that's basically the story of the american southwest, so, /shrug? (see Cadillac Desert and all the water stories out there...)

deelowe 3y ago
Isn't that the same story with Vegas? Would it exist without the hoover dam?
- floatrock 3y ago
  And Los Angeles. And Phoenix. Not saying it doesn't work. Clearly it does, at least for a time or up to a certain level of population (Phoenix is banning new development because it's literally out of water, California is poster-child for water wars). I guess it's something about spending that much effort and human capital to force something so inherently unsustainable that just seems... wasteful? Full of hubris? I don't know, maybe it's just a general sadness that this much ingenuity isn't being spent elsewhere where it could amplify existing natural forces instead of fighting a never-ending battle against entropy for something that doesn't want to exist. Or maybe I'm just an internet sourpuss without enough vision. I just can't shake the "why are we doing this" melancholy about this.
- tracerbulletx 3y ago
  Yeah it wouldn't be a city but just as a fun fact Las Vegas means "The Meadows" it had a really big aquifer and artesian springs fed by the Spring Mountains. It was sustainable as a town without the dam. Vegas also is allocated a very small portion of the water from Lake Mead, Nevada only gets about 4% of what is taken from it every year, and most of that is for farming still. The city probably needs like 1% to survive.

vondur 3y ago

I would really love to see the Los Angeles basin get its primary water needs met from desalination. This would lessen the need for the LA dept. of Water and Power taking water from the Owens Valley north of the LA area which subsequently turned the valley into a desert.

PaulDavisThe1st 3y ago

The article claims that the plan described could produce 5MAF / year (the entire allocation of Colorado River water for California). There's no explanation I could find of where this water will come from. The Salton Sea itself only holds 1.5MAF. The title also seems a bit grandiose. "The US Southwest" for most people I think extends at least as far as the I25 corridor up through NM and CO, and for some it might even reach into western TX. The plan described would really have very little impact on the overall water situation here, even if it did actually live up to its claim of effectively freeing up CA's Colorado allocation.

NegativeLatency 3y ago
Looks like it comes from the Gulf of California in one of the drawings
bryanlarsen 3y ago
The second hand drawn map shows the source pumping station at the Sea of Cortez.

bradford 3y ago

NYT daily had a relevant podcast episode on this (https://www.nytimes.com/2023/09/01/podcasts/the-daily/water-supply-arizona.html https://www.nytimes.com/2023/09/01/podcasts/the-daily/water-...?). Discussion centered around using the water for Arizona, not California. (I'm unable to speak of the relative merits of pumping the water from one state to another). General takeaways: Proponents of the solution seemed to understate challenges and risks associated with: 1. The pipeline itself (i.e., where to build it) 2. The disposal of brine solution into the Gulf of California. 3. Cooperation with Mexico. That's not to say the challenges couldn't be addressed, but discussion of such challenges is noticeably absent from the original article.

photonthug 3y ago
> 3. Cooperation with Mexico Yeah this seems like a big challenge. Even if the Gulf of California is closer, or if it's all downhill, the requirement for international cooperation seems like it would make this a much more complex option than just using the Pacific. Plus if I were Mexico, I'd honestly be looking at the Salton Sea disaster, noticing that some new plan calls for putting salt down in my neighborhood instead of off the LA or San Diego coast.. sounds sketchy. Meanwhile, the Arizona version of this plan is understandable.. Phoenix is thirsty, they have no coast, it's shorter to get to one in Mexico than California and anyway they might actually have better luck dealing with Mexico than California. But can anyone explain briefly why California would want or need the plan to involve Mexico?
- JieJie 3y ago
  Maybe this, since it has to do with Colorado River water. https://www.watereducation.org/aquapedia/mexico-and-colorado-river-water https://www.watereducation.org/aquapedia/mexico-and-colorado...

bilsbie 3y ago

Ok this keeps happening. I posted this exact URL 3 days ago. Shouldn’t the same URL submitted again redirect to mine? Is there a certain cutoff when someone else can submit the same URL? (I’m not complaining, I just want to understand what the rules are)

bell-cot 3y ago
There's a whole lot of randomness in whether (or not) a submission "makes it" on HN. Re-submission cutoffs, crediting the first submitter, etc. would all require more rules & implementation. We pretty much don't care to bother.
CharlesW 3y ago
The kindling of your post didn't catch fire, and this one did. It's not personal. More from @dang: https://news.ycombinator.com/item?id=37126175 https://news.ycombinator.com/item?id=37126175

cs702 3y ago

Wow, what a fantastic post! The author, who holds a PhD from Caltech, proposes taking advantage of the decreasing cost of solar power to enable a new age of clean water abundance in California, sustainably, with the potential for massive revenues and profits at all steps in the value chain. Even if the author's calculations are off by a factor of two, the proposal looks like it could work. At a minimum, it merits serious consideration. The status quo will not solve our pressing environmental problems. The main challenge an innovative large-scale project like this one would face, I think, is a regulatory bureaucracy which to me often seems like it was designed for the technologies and infrastructure of the 20th century, not for those of the 21st century. I shudder to think of, say, inspectors who are highly trained on narrow technical matters, but who lack a fundamental, multi-disciplinary, big-picture view of the entire project, deciding whether to approve individual tiny little parts of it.

photochemsyn 3y ago
It's a very interesting idea - but practically speaking, the kind of water volumes needed for drinking and bathing water for a city like Las Vegas are dwarfed by the volumes needed for the farming of sugar beets, alfalfa for dairy, golf course grass maintenance, etc. If current trends in the American Southwest continue, extreme water conservation will have to become the norm (the other alternative being depopulation of the region).
- digging 3y ago
  Yeah we can't realistically get better water outcomes by only changing out supply. We have to change our usage too. Farms should be converting to crops that have lower water usage, and food manufacturers should be converting to foods that make use of those crops.
Sharlin 3y ago
Skepticism is warranted. The track record of "Oh, we don't have to change our incredibly wasteful and unsustainable ways after all, technology will fix things!" has been... poor.
skywhopper 3y ago

scythe 3y ago

He's doing it wrong. I don't mean some grander point about environmentalism or development, I mean that I have specifically examined solar desalination for the Imperial Valley and he's missed a much simpler way to get the water from point A to point B. See, there's this other basin in nearby Mexico called Laguna de Salada which is basically an empty salt flat about ten meters below sea level. If you flood that by dredging a canal (about 10-20 km and not very high), you only have to transport the desalinated water about five kilometers to get it into the Imperial Valley drainage basin. There's no need to back up the Colorado and mess up what's left of the delta, plus you can put the rejected brine back into the now Golfo de Salada where it will mix more slowly and (hopefully) less destructively with the seawater to the south. The area will still be something of a dead zone, but it would only replace an existing dead zone.

johnohara 3y ago

And then there's the problem of removing all that pesky lithium, 3400 kilotons, enough to support over 375 million electric vehicle batteries, which fortunately, is not very important towards reaching net-zero emissions by 2050. [0] https://www.energy.gov/eere/articles/us-department-energy-analysis-confirms-californias-salton-sea-region-be-rich-domestic https://www.energy.gov/eere/articles/us-department-energy-an...

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joescharf 3y ago

I've been thinking about this as well. As climate change affects the distribution of potable water on the planet, it would seem prudent to start installing solar backed desalination and water pipelines to ensure water security for areas at risk. Now I'm no hydrologist, and haven't researched this idea deeply yet, so don't know second and third order effects (i.e. brine disposal mentioned above, and of course the economics of such a venture.) It seems at some point our collective hands may be forced and we may have to do something that doesn't make a profit, yet sustains humanity as a going concern. Finally, the fact that we haven't "terraformed" in this fashion drought-stricken places like Africa or elsewhere is a pity. But yes, economics, profit, geopolitics, power struggles, I get it.

rindalir 3y ago
I am really appreciating the IANAH and TINHA side effects of your post :)

yinser 3y ago

I thought this would be a post from Rain Maker but it is another promising project altogether. If you’re interested check out Augusts Doricko’s company looking to do cloud seeding in the same region https://www.makerain.com/ https://www.makerain.com/

solardev 3y ago

I wonder if this would be cheaper than just paying the water rightsholders not to use the water? If the Salton Sea doesn't have a steady input (from snowpack? not familiar with it), doesn't desal mean we're really just expanding the unsustainable use of the Colorado, maybe delaying it another few decades, but ultimately still growing more and using more water than its watershed can naturally sustain -- especially as climate change increases? I think the fundamental problem here isn't that we need to make more freshwater out of brine, but that the California (and other) water rights are set to levels that cannot realistically be maintained. The law needs to change even if that hurts the grandfathered rightsholders; there just isn't the same amount of water anymore.

connorgutman 3y ago

We desperately need to focus on conservation efforts instead of attempting to engineer "solutions" that only end up encouraging further consumption. Hot take: Maybe the American SouthWest wasn't meant to support > 1/3 of America's agricultural output. Solar desalination of the Salton traps humanity in an energy contract when we could achieve meaningful conservation efforts instantaneously by banning the production of many water-intensive luxury crops. Why is Arizona farming alfalfa for Saudi horses? Why is California producing 2.8 billion pounds of almonds a year? Why is the United States one of the highest consumers of red meat in the world when sustainable plant-based alternatives exist and use a fraction of the water? This regional water crisis (as well as our global climate crisis) cannot be solved without making bold sacrifices to our daily lives. I know this is Hacker News, but not everything can be solved with new/additional technology.

nozzlegear 3y ago
> We desperately need to focus on conservation efforts instead of attempting to engineer "solutions" that only end up encouraging further consumption. With respect, why can't we do both?
- connorgutman 3y ago
  I’m not against using technology but my concern is that we need to treat resource consumption as a form of addiction. Humanity frequently uses technology as an excuse to further consume instead of using it to pay off ecological debt.
njovin 3y ago
This is so dead-on it hurts. The "taming" of the rivers in the American west by the Army Corp of Engineers has been romanticized and the underlying motives have been swept under the rug: we prioritized these massive public works projects to provide cheap water to big ag businesses at the cost of sustainability and residential access. IMO we should absolute not be exporting anything farmed with subsidized water while the survivability of just living in the US southwest is uncertain due to current water levels and climate patterns. That seems like the lowest of low-hanging fruit.

alexb_ 3y ago

Just charge people for the natural resources of the country via taxes. Resource and land taxes solve basically every single problem in the current American economy yet people do not want to even think about doing it.

jakderrida 3y ago
> yet people do not want to even think about doing it. probably because placing a price on some things seems too transactional. Not saying you're wrong, though. Just saying that's why. The alternative is allowing more rapacious disregard for the aggregate negative effects on everyone as a whole.
School-Cotton 3y ago
Plenty of people are thinking about it, including you. The issue is that the American makes it structurally impossible to pass any major reform on any controversial topic.
justinator 3y ago
You're right - air's also getting a little too polluted for my taste. Maybe if I could get a hold of some taxed air, I could breath easy! We could put the pollutants back into the untaxed air too!
- alexb_ 3y ago
  Why are you acting as if this is some fantasy thing? Pollution taxes absolutely are exactly what that is. You're "using up" all the good air!
shermantanktop 3y ago
US taxes are already complicated, in large part due to the effort to build incentives and disincentives in the way that you describe. And yet the process to build the existing incentives is inescapably political, and for good reason: if you impose a significant change to taxation, there are winners and losers on day 1. Nobody likes to lose, especially if they feel they are doing nothing wrong. For your specific idea, the red/blue political map shows you who will probably lose.

MostlyStable 3y ago

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".

shermantanktop 3y ago
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 3y ago
  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.

amarant 3y ago

Seems to me like atmospheric water generators are a good fit here. That gets rid of the brine problem entirely, and from what I've read it's competitive in terms of energy consumption. https://solarimpulse.com/solutions-explorer/high-efficiency-atmospheric-water-generators https://solarimpulse.com/solutions-explorer/high-efficiency-...

elmolino89 3y ago

I am by no means a desalination expert, but pumping vast amount of a salty water 100+ kilometers (Pacific Coast) or from the Sea of Cortez (closer to 200kms) seems strange as compared to building the desalination plant on the shore and transfer the electricity generated in the desert. One can also replace some drinking or agricultural water used way closer to the coast in CA from the Colorado Basin with the newly desalinated one. Way less pumping. Or do I miss something?

konschubert 3y ago
You are right. Power is easier to transport than water.
- elmolino89 3y ago
  I have spend few years in San Diego doing hikes inland. There are decently sized mountains in the desert between say Borrego Springs and the coast. Not an optimal area to build a pipeline cheaply. Pipe going along Colorado river should have less bumpy course but there is a biosfere reserve just on the top of Baja California. Not a good spot to suck giant volumes of sea water, even less so to construct a pipeline or heavens forbid dump the concentrated brine.

adrianmonk 3y ago

> The solar panels convert wasted sunlight into electricity, one of the most useful forms of energy, at the lowest cost ever in human history. The batteries make this power available at night, enabling 100% utilization of the higher capex systems downstream. The RO desal plant uses this power to strip salt out of fresh water I wonder if you could store the energy as pressure instead of electricity in batteries. From what I gather[1], the biggest energy draw in reverse osmosis is pressurizing the water to force it through the RO filters. So, while the sun is shining, fill a tank halfway with salty water, then use solar energy to run pumps to pressurize air above the water. When the sun isn't shining, you now have pressurized water you can let through the RO filters. Compared to a regular RO plant, this requires high-pressure storage tanks and additional pumps. I'm unsure whether that costs less than batteries or not. Another part of the analysis is that, if you do build the batteries, they can earn extra money with a side gig stabilizing the grid. Occasionally, when grid conditions get very gnarly, you could shut down the RO plant for a few hours and make a quick buck selling your battery power on the market. Alternatively, you could pump the water uphill during the day and let gravity supply the energy to force it through the RO filters at night. This means you'll have to build a special reservoir for pre-treated salty water somewhere, though, and you need a lot of pressure, so it would need to be at a high elevation. --- [1] Source (kind of old): https://www.oas.org/dsd/publications/unit/oea59e/ch20.htm https://www.oas.org/dsd/publications/unit/oea59e/ch20.htm

amluto 3y ago
A fundamental challenge with storing pressure is that water is essentially incompressible. This means that you can’t build a 1000 gallon tank and store any useful amount of energy in the form of pressurized water in that tank. Mathematically, it’s easy to forget that the PV term in enthalpy is a mathematical trick, not a physical thing, and that it mostly does a nice job explaining physical things when P = atmospheric pressure. If you want to store, say, 100psi water, the energy you care about is P times delta V, so you need some thing that can change its volume easily, cheaply, and reversibly while under pressure. As a practical matter, this means compressed air or maybe springs. So that water “pressure tank” is actually an air pressure tank that happens to have some water in it too. There’s nothing wrong with storing pressurized air, except that it’s a heck of a lot more dangerous than storing pressurized water due to the fact that it really does have energy stored in it. (There’s a reason that a PVC pipe filled with 80psi water is a common thing in houses and the main danger is that water escapes if it breaks. A pipe full of 80 psi air is quite hazardous.) There are startups that have played with compressed air energy storage. The resulting gizmos are large. I would expect a RO plant that is optimized for intermittent use without any energy storage at all to end up being a viable alternative to energy storage, but maybe batteries will end up being cheap enough that this isn’t worthwhile.

bparsons 3y ago

The details might be a bit goofy, but this sort of large scale geoengineering project is going to be the only way that the SW is going to remain inhabitable. The American southwest has a couple big things going for it -- unlimited sunshine and an extraordinary amount of empty land. You can combine these things to create huge amounts of electricity which can be used to irrigate new farm land, power mines and build new cities. The status quo of drawing down on the increasingly precarious water supply is not feasible though. Before the unprecedented snowpack of 2022/2023, many regions were facing extreme water rationing.

drkevorkian 3y ago
Habitable? There is plenty of water for it to be habitable, residential use is a drop in the bucket compared with agricultural use. Without a technological solution, we'll have to scale back agriculture, but that's not a regional problem, since the market for food is an international one.
- ianburrell 3y ago
  Also, we don't have to get all of the water from desalination. Southern California can use desalination, which makes sense to the ocean, short distances, and solar power. That frees up Colorado River water that Nevada and Arizona can use. Desalination will probably never be worth it from agriculture, but agriculture should survive on the water they can access after people.

thelastgallon 3y ago

If we switch to renewables, there will be plenty of water, which is now used by fossil fuels. U.S. thermoelectric plants are the largest source of U.S. water withdrawals, accounting for more than 40% of total U.S. water withdrawals in 2015.: https://www.eia.gov/todayinenergy/detail.php?id=50698 https://www.eia.gov/todayinenergy/detail.php?id=50698

hnu123 3y ago

There's an abundance of freshwater in the east coast, northwest and midwest. Why not shift some of the exess water from the great lakes, east coast and northwest to southwest? Can't we pipeline the water to giant reservoirs in the sw or even carve extend tributaries from the missouri river or create canals down to the sw? It's not exactly rocket science.

ianburrell 3y ago
Way, way too expensive. Pumping water east of the Rockies would use a ton power. Local desalination would cost way less. This plan is not feasible because it pumps water from Sea of Cortez to Salton Sea over 200 mi.

01100011 3y ago

A solution is there if we had the will to implement it: https://www.osti.gov/biblio/963122 https://www.osti.gov/biblio/963122 Take excess water from SE floods and pump it west opportunistically using excess renewables. Bonus because you can use the pumped water as gravity storage. Yes, it is not cheap, energetically, to pump water. Yes, you have to cross a big mountain range(which increases opportunities for gravity storage). For some reason, this suggestion always gets a lot of comments from folks living around the great lakes who think we're going to 'steal' 'their' water(just like they 'steal' CA grown produce, I guess?). Anyway, a national water grid is needed for national food security and can mitigate flooding damage in the SE(probably more important b/c of AGW).

downut 3y ago
That report is mainly about the upper Mississipi (Midwest) not the lower, or points east (Southeast). And it is only supposed to run during large scale flood events, which the report cites as lasting ~80 days, worst case? Looking at flood event frequency, this report cites: 1912, 1913, 1927, 1937, 1965, 1973, 1982, 1993, and 2008. So, let's be generous and double the event length to 160 days and double the event frequency to ~20 per century (increasing, to be sure). That's a time utilization of the infrastructure of ~9%, if Ima doing the math right. It is apparently true: water runs uphill toward money. In this case, literally multiple miles of vertical elevation gain to get it to the Navajo Nation. I mean I could see maybe pumping to Denver, or maybe over the continental divide past Denver, but... direct to almost the NM, AZ border? Maybe just start with baby steps and for instance charge those good enterprising folk who farm alfalfa with nearly free water in the AZ desert and ship it to Saudi Arabia.

palmfacehn 3y ago

https://energycentral.com/c/pip/great-mexicali-energy-and-shipping-canal https://energycentral.com/c/pip/great-mexicali-energy-and-sh... Here's an alternative proposal based on a sea level canal and tidal power.

llsf 3y ago

Maybe we should not use so much water (for agriculture) in a desert area at the first place. Feels like we are putting fixes on top of fixes. "A Saudi Arabian company grows alfalfa on farmland in Arizona and California and sends it overseas to feed the country's cows. These legal farming operations extract groundwater in Arizona and water from the Colorado River across the border in California, experts say." source: https://www.maxwell.syr.edu/news/article/koch-discusses-saudi-arabian-farms-using-water-from-arizona-and-california-in-kusa-article https://www.maxwell.syr.edu/news/article/koch-discusses-saud... Maybe if we stop exporting Colorado water packed in alfalfa and other agri-products, we would have enough water ? Exporting water through alfalfa to Saudi Arabia who indeed banned alfalfa fields in their country because it was consuming just too much water, is one of the problem we should fix before installing PV and batteries in the desert, and dump concentrated brine somewhere.

skywhopper 3y ago

Lots of questionable assumptions in this article, but I wanted to call this particular calculation out because it's so blatant: 5 MAF/year of 6% salinity brine contains more than 10 million tonnes of magnesium, comparable to current global production, not to mention other light metals. At spot prices around $5000/T, a mature brine extraction industry could net >$50b/year "Net" means after expenses, so this calculation is assuming that extracting 100% of the magnesium from the brine would have zero cost, not to mention that it also assumes that doubling the world supply of magnesium would have zero impact on its price.