[HN Gopher] A vision for the alleviation of water scarcity in th...
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A vision for the alleviation of water scarcity in the US Southwest
Author : boiler_up800
Score : 114 points
Date : 2024-01-12 15:48 UTC (7 hours ago)
(HTM) web link (caseyhandmer.wordpress.com)
(TXT) w3m dump (caseyhandmer.wordpress.com)
| deegles wrote:
| Would it be more efficient to use solar thermal for some of the
| desalination instead of $10b worth or regular solar?
| gorkish wrote:
| If efficiency is the metric you're going for, move the people
| and do nothing. It's probably what will happen eventually
| anyway.
| chmod775 wrote:
| 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.
| missedthecue wrote:
| Moving 50 million people seems to me to incur more effort
| than building $10b of solar
| konschubert wrote:
| Yea but that wouldn't be disruptive so it's no fun /s
| martythemaniak wrote:
| 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_...
|
| From this post: https://www.volts.wtf/p/which-technologies-get-
| cheaper-over
| hnmullany wrote:
| 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: Jimenez-Arias, D., Morales-Sierra, S., Garcia-Machado,
| F.J., Garcia-Garcia, A.L., Luis, J.C., Valdes, F., Sandalio,
| L.M., Hernandez-Suarez, 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.
| zbrozek wrote:
| Is there a way to know how much to care? We do all sorts of
| things that displace species, so having some way of
| contextualizing and weighting the harm against the benefit
| would be helpful.
| monkeynotes wrote:
| Seems to me it would initially be a narrowly scoped to the
| immediate outflow. As the brine dissipates I assume it will
| be normalized by the rest of the ocean as it's diluted.
|
| However, as with all human endeavours, scaling up will scale
| up the problem. And we won't pay attention to that until it's
| a huge issue.
| jakderrida wrote:
| > However, as with all human endeavours, scaling up will
| scale up the problem.
|
| This just makes your prior point seem like it comes from a
| needlessly misanthropic place.
| solardev wrote:
| Not the OP, but I think humans in general find it
| difficult to scale up. Whether in software or
| manufacturing or politics or environmental issues, we're
| much more equipped to deal with 1 or 10 of something than
| 100,000 or 1 trillion of it.
|
| At the end of the day we're still limited by our biology
| and brains, evolved for very different setting than the
| world we now live in. We try and we get by but by and
| large we're not doing great at large scale issues,
| whether it's jobs or housing or healthcare or saving the
| planet or just plain getting along with each other.
|
| We're primates adapted for small group living in local
| communities, abruptly given way more power than our
| biology was designed for. Is that misanthropic? I dunno.
| If dolphins had opposable thumbs, they'd probably have
| gotten themselves into a similar bind.
| monkeynotes wrote:
| Whether it's misanthropic or not is moot if it's just a
| plain fact.
| solardev wrote:
| Yeah, true too.
| solardev wrote:
| This is necessarily a value judgment, isn't it? There are
| tools like lifecycle analyses and environmental impact
| reports and threatened species lists that can help
| estimate/enumerate impacts. But ultimately how much to care
| is a personal question, and people are going to disagree over
| whether some small fish or rare owl or fluffy panda is worth
| more or less than someone's job or a local industry or just
| some other charismatic species.
|
| Species will always come and go, and they're going to die off
| faster than we can protect them, sadly. We only get to decide
| which ones to prioritize, at different personal, local,
| national, global levels etc.
| bobthepanda wrote:
| The Canaries have 32% of the economy based on tourism, and a
| good chunk of that depends on the local ecology (scuba, nice
| beaches, etc.)
|
| If you want to see what a tourism place looks like when you
| destroy its ecology, you only need look at the abandoned
| areas around the Salton Sea.
| palmfacehn wrote:
| The Salton Sea in its current iteration was created by the
| failure of an irrigation canal. Before that there was no
| Salton Sea as we know it or tourist area.
| bobthepanda wrote:
| Sure, but that's beside the point of the question, which
| is "how do we know salinifying an area enough to kill
| species is bad"
| nickparker wrote:
| > RO desal splits the incoming ~3% salinity stream into two
| halves, one fresh and one ~6% salinity. This concentrated brine
| is fed to adjacent brine processing facilities (ideally in both
| countries) that exploit the region's abundant solar and
| geothermal energy to extract potentially millions of tonnes of
| lithium, sodium, magnesium, chloride, and other metals found in
| sea water. The resulting depleted brine is piped back to the
| ocean where it is thoroughly mixed with sea water and
| discharged.
|
| Casey's proposing we mine the brine for useful minerals. You're
| right he's glossing over details, but a citation addressing the
| economics of brine disposal with his proposed processing would
| add more to the discussion.
| thehappypm wrote:
| Basically, I think you could take the Brine and just put it
| somewhere else. Like, into mine shafts, or into evaporation
| pools for mining purposes.
| ruined wrote:
| the intent of the project is the conversion of a saline
| lake to freshwater, not the creation of a saline lake.
| mechanical_bear wrote:
| If you give a mouse a cookie...
| solardev wrote:
| ...be sure to give it an opt-out pop-up too?
| tarr11 wrote:
| From https://www.frontiersin.org/articles/10.3389/fmars.2022.
| 8451...
|
| " In general, anthropogenic activities pollute the coastal
| marine environment, altering the environment's physiochemical
| properties and resulting in changes in marine communities.
| Physiochemical conditions can be altered by the presence of
| pollutants, hypoxia, organic enrichment, decreased
| hydrodynamic conditions, and, more recently, brine discharge
| (de-la-Ossa-Carretero et al., 2016). Salinity elevation in
| receiving soil and water bodies and the territorial
| consequences of brine with high total dissolved solids on
| benthic marine life close to the discharge site are the most
| important environmental challenges associated with brine
| disposal (Miri and Chouikhi, 2005; Panagopoulos et al.,
| 2019)."
|
| Lots more detail in the article on studies of specific
| populations as well as discussion of mitigations and
| alternatives.
| mikeyouse wrote:
| We just simply don't need that much brine for useful minerals
| -- it's a huge cost and you'll be left with _massive_ piles
| of mostly useless salt.
|
| On one of my hard drives, I've got an engineering /
| construction plan for a moderately sized intake + discharge
| for a small RO facility that would've passed muster in
| Australia, which has pretty reasonable environmental
| protections. Round numbers - the intake would have cost $25
| million and the discharge more like $75 million. You need a
| _massive_ structure to be able to emit that brine back into
| the environment in a way that doesn 't just nuke the
| surrounding marine life. Huge pipes + check valves +
| cascading discharges, all either on the ocean floor if there
| aren't reefs and other sensitive areas or even worse from a
| cost perspective, tunneled out to a depth that can handle the
| amount of salt.
|
| Seawater is ~35g/L of TDS - the author is talking about 5
| million acre feet of desal - what's that, 20 million tons of
| salt annually?
| 0xNotMyAccount wrote:
| This is doable. Many coastal wastewater systems already
| have large pipes that extend miles to sea (1), and that's a
| rounding error compared to the many more miles of pipe
| routing sewage to the plant (2, pg A-3)
|
| (1) https://www.wateronline.com/doc/new-10-mile-long-
| sewage-tunn...
|
| (2) https://www.sandiego.gov/sites/default/files/ploovol4_1
| 5.pdf
|
| Pipes tend to last a long time, in large part because it's
| relatively straightforward to manage the chemistry problem
| in the pipes.
| bbarnett wrote:
| https://slimemoldtimemold.com/2021/08/02/a-chemical-
| hunger-p...
|
| This guy claims that Lithium _may_ be partially responsible
| for some weight gain in our population, but also, that
| desalination plants cause extra lithium as well.
|
| If it was mined out, that would be viable, but if not...
| blacksqr wrote:
| In an environment where solar and geothermal electricity are
| abundant enough to make this work, it would be far easier to
| condense water straight from the air by refrigeration.
| konschubert wrote:
| I think you're underestimating how much less efficient that
| is.
| solardev wrote:
| It worked for Uncle Owen
| heleninboodler wrote:
| :D and if you scale this to the point where the amount of
| water vapor in the atmosphere is affected, you can also use
| some of the abundant energy to boil the ocean to replace
| that water vapor. :) Same net effect (water is taken from
| the ocean and salt is not) without actually moving the salt
| back and forth.
| ketchupdebugger wrote:
| The naive solution is to just dump the brine back into salton
| sea, its already too salty for marine life, so whats a little
| more salt?
|
| >flaunt its unequaled excellence by exporting alfalfa to all
| corners of the globe.
|
| really not sure if this is satir.
| hcknwscommenter wrote:
| Your naive solution just creates an even more gigantic
| stagnant stinky mess of a Salton "sea". The entire point is
| to reengineer the salton sea as a beautiful ecosystem and
| lake by diluting all the salt with 5MAF of RO desalinated
| water. The added benefit is huge economic revitalization of
| the entire area. Plus, because of the value of minerals in
| the brine, and the cost-effectiveness of solar power, it is
| not as expensive and crazy of an idea as one might think.
| bilsbie wrote:
| It sucks you guys home in on some weird issue for every
| promising technology.
|
| He literally addresses brine in the article.
| solardev wrote:
| It's a community of hackers passionate about the way things
| work. Picking it apart helps everyone understand the inputs
| and outputs of a system to understand how feasible it is, and
| what the tradeoffs are. What would you prefer, a generic
| "that's nice"?
|
| As far as I can tell, the author just kinda glossed over the
| brine situation. Some minerals can be sold, but his solution
| for the excess salt was just to turbulently mix it back into
| the ocean, if I'm reading correctly. The sibling comments
| here explain why that isn't trivial (cost and wildlife
| impacts). I found them illuminating!
| hnu123 wrote:
| > It's a community of hackers passionate about the way
| things work.
|
| No it's not. It's a community of corporate, media and tech
| people opposed to hacking and the hacking ethos. It's
| mostly a business forum.
| solardev wrote:
| Well yes, that too. A mix of both, not sure of the
| percentages.
|
| Frankly I wish there were a better place for the hackers
| to congregate without the capitalists. But whatever, at
| least the discussion here is civil and interesting. Best
| place I've found since Slashdot of old.
| hnu123 wrote:
| > But whatever, at least the discussion here is civil and
| interesting.
|
| It's civil. Nothing interesting about the comments at
| all. Even the dullest person on earth would find the
| comments mundane and boring.
| solardev wrote:
| Well, if you don't find them interesting, you don't have
| to be here? Many of us still do find value here.
|
| Do you have other similar forums you recommend?
| sixstringtheory wrote:
| This is some negging bs.
|
| Current front page items include a paper on vector
| databases, an example of AI garbage that showed Amazon in
| a bad light, a quite in-depth treatment of "Trilinear
| Point Splatting for Real-Time Radiance Field Rendering"
| hosted on a PhD's own github page, you know github, a
| huge gathering place for hackers to share their code with
| each other? An article criticizing Unity about banning an
| open source LGPL application, written by a developer of
| said open source product, introducing a competing
| platform to further decentralize the app store landscape,
| an article critical of Boeing, an article critical of
| Apple, a radical rocket design, bluetooth mesh
| networking, an open source python notebook project, an
| indie developer's project to run stable diffusion in an
| iOS app instead of from some corporate server, an article
| on the ethics of immersive tech, an article on mysticism
| and empiricism, an article on epistemology...
|
| Yeah, real dull business environment here. I'd totally
| rather go back to my training on peer performance
| reviews.
|
| If you can't find anything interesting on this site, it
| is a _you_ problem.
|
| "If you run into an asshole in the morning, you ran into
| an asshole. If you run into assholes all day, you're the
| asshole."
|
| We're all so sorry that you can't just do whatever you
| want while unleashing the externalities on society at
| large. You want to hack, go do it in your basement where
| you can't affect the rest of us. You want to _engineer_ ,
| you have to answer to more people than just your mom
| asking what you want for dinner.
| hnu123 wrote:
| > This is some negging bs.
|
| It's called the truth. Morons, or wannabe hackers, tend
| to be offended by it.
|
| Why are you so triggered? All I said was this forum is a
| business forum. That is a statement of fact. It was
| founded by a venture capitalist to assist his venture
| capital firm find and fund start ups. Hence why Hacker
| News was originally called Startup News.
|
| 'Launched February 19, 2007; 16 years ago as Startup
| News'
|
| https://en.wikipedia.org/wiki/Y_Combinator
|
| It's bizarre that you'd be so offended by truth. You are
| not quite hacker material it seems.
| JohnMakin wrote:
| He addresses brine, but not the waste products that come from
| brine, and only addresses it in one sentence:
|
| > The resulting depleted brine is piped back to the ocean
| where it is thoroughly mixed with sea water and discharged.
|
| This is not nearly as easy as this sentence implies.
| konschubert wrote:
| Brine is just concentrated seawater. What waste products?
| digging wrote:
| The waste product is brine. It's an extremely salty
| sludge that's toxic to marine life. In the same way that
| fresh water is "just" diluted seawater, but pumping
| millions of gallons of it into a coastal ecosystem would
| wipe it out.
| photonbucket wrote:
| The pipe should really go a dozen miles out to sea and
| then get pump-mixed with the destination water
| tuatoru wrote:
| Yes it is. We do it with urban wastewater in thousands of
| locations around the world. This is not a hard problem, nor
| is it expensive.
| hnmullany wrote:
| Waste brine is substantially more dense than regular
| seawater, so it tends to form a coherent layer that
| doesn't mix easily: it's why waste brine sinks to the
| sea-bed and spreads out in a layer.
| messy wrote:
| They provide some detailed and constructive thoughts. What
| exactly does your comment provide? Some sort of complaint
| which could be solved by yourself by not going into the
| comments or not reading theirs, hope this helps you in the
| future.
| pfannkuchen wrote:
| Can't we pipe the seawater inland and then deposit the salt on
| land?
| bell-cot wrote:
| When it rains, what happens to the run-off from a huge pile
| of salt?
| mrguyorama wrote:
| 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 , 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.
| jvanderbot wrote:
| Perhaps the net effect is ostensibly positive, given the
| greening and habitation of that blighted area in CA.
| obblekk wrote:
| There should definitely be a plan for the brine.
|
| I'm optimistic we could:
|
| * Build ocean pipelines that disperse brine over much larger
| volumes of water to minimize impact on wildlife
|
| * Dump the brine water in engineered desert fields where it
| will evaporate and deposit salt reserves.
|
| In general, we should be aware of the whole lifecycle of a
| solution, and optimistically believe we can solve each problem
| with more work.
| margalabargala wrote:
| > Dump the brine water in engineered desert fields where it
| will evaporate and deposit salt reserves.
|
| Honestly, the Salton Sea would be a great place to dump the
| brine. It would keep the water levels up and reduce the
| respiratory issues caused by drying, and any ecosystem to be
| destroyed has been thoroughly destroyed for decades.
|
| Nix the "turn the manmade salt lake to a manmade fresh lake"
| plan, and use the created freshwater for agriculture
| directly, or send it off to LA, or do anything with it that
| isn't "refill the accidental lake that already has
| evaporation and pollution issues". It's a salt lake, use it
| as one.
| solardev wrote:
| This is something I still don't understand about the
| original plan: Where is the Salton Sea expected to get more
| water from on an ongoing basis? If you keep extracting from
| it and not refilling it, it's just going to keep getting
| smaller and saltier. Agriculture isn't going to put back
| out as much as it takes in (the plants need it, after all).
| Sure, you can drag it out a few more years with desal, but
| eventually it's not going to be much of a sea, just a salty
| pile.
| bryanlarsen wrote:
| AFAICT, water is pumped from both the Sea of Cortez & the
| Salton Sea to a desal plant. The fresh water is used for
| irrigation etc, and the runoff from primary use
| replenishes the Salton.
| digging wrote:
| Huh, I guess I was mistaken that restoration on the Salton
| Sea was already in progress. I've seen large flocks of
| birds in and around it and assumed there was food for them
| in it. But it sounds like no, it's still horrible.
| Accujack wrote:
| The Salton sea is the home of a huge lithium deposit, and
| it's unlikely that anything but geothermal and lithium
| mining will happen there in the near future. Certainly not
| "restoration" to what it was when it was accidentally
| created.
| konschubert wrote:
| If you desalinate 1 gallon of seawater, and then mix the brine
| with 10 gallons of seawater, the salt content of that seawater
| has increased ~10 percent.
|
| If that's still too much, use 20 gallons.
|
| It's a matter of spending energy on pumps, but it's totally
| doable.
|
| Also, the ocean salt content will not be increased by this,
| since the desalinated water will eventually make it back to the
| ocean.
| jryb wrote:
| But where are you getting that pure seawater from? If it's
| anywhere near the outlet, there's a scale at which the
| concentrated brine will affect the salinity of your inlet.
| konschubert wrote:
| Yes, some pipes are needed. Beyond that, you rely on ocean
| currents. .
| BytesAndGears wrote:
| Yeah, but if you're pulling in water and disposing it from a
| specific region, eventually the water that you're pulling in
| is progressively saltier, and you're compounding the
| saltiness of that area.
|
| I'm sure that ocean currents will eventually equalize the
| salt, but if you're continuously dumping salt into a specific
| area, it's going to make that region of the ocean saltier.
| konschubert wrote:
| You need pipes to spread it out. And I think you may be
| underestimating the scale and force of ocean currents.
| Every tide probably moves more water than California uses
| in a year.
| solardev wrote:
| I don't think the ocean is equally saline everywhere:
| https://salinity.oceansciences.org/maps-global.htm
|
| On average it's pretty close, but you can definitely get
| impacts from increased local salinity: https://onlinelibr
| ary.wiley.com/doi/full/10.1111/gcb.16859 (just random
| ecamples)
|
| https://www.scientificamerican.com/article/slaking-the-
| world... (view in incognito)
| konschubert wrote:
| Okay fair point.
| nradov wrote:
| Brine discharge is an issue, but the geography of the North
| American West Coast is favorable for that. In most places the
| seafloor drops down fairly deep just a short distance offshore.
| Past about 400 ft / 120 m there is no flora at all, and most
| fauna is clustered around rock structures. So, the impact of
| brine discharge can be minimized with careful pipeline siting.
| ed_balls wrote:
| you could use brine for construction (Isreal build a wall along
| Jordan). Also you can pump it into a ship and dump into
| Pacific, slowly.
| gwern wrote:
| Your quote doesn't give any evidence it is a big problem. It
| simply _asserts_ that it is a problem and includes some random
| factoid about the cost.
| floatrock wrote:
| 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 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 wrote:
| Isn't that the same story with Vegas? Would it exist without
| the hoover dam?
| floatrock wrote:
| 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 wrote:
| 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.
| bryanlarsen wrote:
| AFAICT, restoring the Salton Sea and capturing the land
| appreciation is the mechanism for funding the project, not the
| goal. The goal is to restore the Colorado river.
| floatrock wrote:
| And what pays for it again in a decade when the corroded
| water pipelines start to need replacement?
|
| Or 30 years when the solar reaches end of life?
|
| I assume original developers will have cashed out by then,
| someone else is left holding the bag, and the Salton Sea
| collapse story plays out a second time because it's just too
| expensive to maintain. That, or it's an exclusive enclave to
| the LA ultra-wealthy who don't mind that the high taxes keep
| the undesirables away, all while they've gotten the state to
| subsidize their vacation homes because the state is trapped
| and can't afford not to keep the machine running.
| datadrivenangel wrote:
| We must maintain our life support machines.
|
| Or move to places that don't need them.
| bryanlarsen wrote:
| High property values and rich residents mean lots of
| property and income taxes to pay for maintenance.
| tracerbulletx wrote:
| We're already doing that with dams.
| vondur wrote:
| 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 wrote:
| 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 wrote:
| Looks like it comes from the Gulf of California in one of the
| drawings
| bryanlarsen wrote:
| The second hand drawn map shows the source pumping station at
| the Sea of Cortez.
| bradford wrote:
| NYT daily had a relevant podcast episode on this
| (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 wrote:
| > 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 wrote:
| Maybe this, since it has to do with Colorado River water.
|
| https://www.watereducation.org/aquapedia/mexico-and-
| colorado...
| bilsbie wrote:
| 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 wrote:
| 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 wrote:
| 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
| cs702 wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| His calculations are off by much more than a factor of 2. Maybe
| two orders of magnitude.
| scythe wrote:
| 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 wrote:
| 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-an...
| joescharf wrote:
| 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 wrote:
| I am really appreciating the IANAH and TINHA side effects of
| your post :)
| yinser wrote:
| 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/
| solardev wrote:
| 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 wrote:
| 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 wrote:
| > 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 wrote:
| 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 wrote:
| 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.
| voakbasda wrote:
| This _is_ Hacker News. Even if everything ultimately cannot be
| solved by technology, we sure as hell are going to give it our
| best try. That's literally our most abundant resource here.
| kayson wrote:
| Arizona is starting to solve the alfalfa problem at least
|
| https://www.nytimes.com/2023/10/03/climate/arizona-saudi-ara...
| danaris wrote:
| > We desperately need to focus on conservation efforts instead
| of attempting to engineer "solutions" that only end up
| encouraging further consumption.
|
| "We desperately need to find ways to massively change human
| nature, rather than using our vast combined expertise to
| engineer solutions that let human nature work for us rather
| than against us."
|
| Any solution to a systemic problem that can be articulated as
| "If people would just..." is doomed to fail. People will _not_
| just. People will continue finding ways to convert resources
| into better lives--for better and for worse.
|
| Posting on articles like this saying "No! We can't keep finding
| ways to make consumption not harm the ecosystem! We have to
| force people to live austere, monk-like lifestyles! Only that
| will _truly_ save us all! "
|
| Like, I'm as frustrated by the idiocy of growing almonds in
| California as the next guy, but if this solution will _actually
| work_ the way it claims to, then we may not need to _worry_
| about that anymore. And furthermore, it would mean significant
| improvements for various other parts of the world currently
| reliant on transporting enormous quantities of fresh water long
| distances to coastal areas.
| alexb_ wrote:
| 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 wrote:
| > 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.
| umanwizard wrote:
| 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 wrote:
| 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_ wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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.
| obblekk wrote:
| 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 wrote:
| 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 wrote:
| 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
| danaris wrote:
| > 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.
| amarant wrote:
| 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-...
| elmolino89 wrote:
| 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 wrote:
| You are right.
|
| Power is easier to transport than water.
| elmolino89 wrote:
| 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 wrote:
| > _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
| amluto wrote:
| 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.
| warcher wrote:
| Batteries have proven _extremely resistant_ to the scaling of
| solar panels. I would love to be wrong about this, but
| overwhelmingly people with an agenda just kind of hand-wave
| past grid scale energy storage problems that we have
| generations of evidence against being easily or cheaply
| solvable.
|
| The thing about this plan that I _love_ though, is that who
| cares if the desal plant runs at night? Desalination can take
| all of the power you can feed it and then some, and if it
| shuts off after sundown, who cares? Stop filling your
| freshwater reservoir until morning, at which point you just
| run flat out all over again.
| adrianmonk wrote:
| It does matter, though. Suppose you need X amount of fresh
| water output per month. And suppose that for Y dollars, you
| can build a plant that supplies X _if_ it runs 24 hours per
| day.
|
| If, instead, you can only run your plant 8 hours per day
| instead of 24, then you need to build a plant three times
| as big, which costs 3Y dollars.
|
| This is where batteries (or other energy storage) may
| become useful. If you can build them for less than 2Y
| dollars, then you can build the whole system for cheaper.
| warcher wrote:
| What I'm saying is that the freshwater reservoir _is_ a
| totally free grid scale battery for a desal plant. No
| need to save it, just make fresh water while the sun
| shines and drink it whenever.
| adrianmonk wrote:
| Energy storage would serve _two_ purposes:
|
| (1) Ensure you always have fresh water available since
| you're continuously producing it.
|
| (2) Reduce the size of desalination plant you must build
| by allowing you to run it 24x7.
|
| You're right that you can just store the fresh water, so
| batteries aren't needed for #1. But the article is
| talking about how to achieve #2.
| amluto wrote:
| My question is: should it actually cost 3Y? Sure, if you
| take an off-the-shelf design and triple it, it will cost
| around three times as much.
|
| But there should be at least some efficiencies that can
| be gained. For example, energy conversion is not cheap.
| Rather than building solar inverters that produce 480VAC
| and using 480VAC pumps or pump drives, what if the pumps
| ran on DC?
|
| Or, for more fanciness, what if the pump drives were
| themselves the MPPTs? Have the solar panels arranged so
| they produce a sufficient voltage for the motor drive bus
| even at minimum output, and make the drivers smart enough
| to run the right number of pumps at the right power and
| to do so while tracking the maximum power point? That's a
| lot of power electronics that could be avoided.
|
| Also, if a plant is willing to store a day's worth of
| seawater and brine, then the intake and discharge systems
| only need to be sized for maximum daily average flow, not
| peak sunshine flow.
| bparsons wrote:
| 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.
| thelastgallon wrote:
| 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
| hnu123 wrote:
| 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 wrote:
| 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 wrote:
| A solution is there if we had the will to implement it:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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-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 wrote:
| 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.
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(page generated 2024-01-12 23:02 UTC)