A vision for the alleviation of water scarcity in the US Southwest
caseyhandmer.wordpress.com
caseyhandmer.wordpress.com
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.
"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.
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".
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.
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.
That being said, thanks for the heads up! However, it really just strengthens my point that even more countries are using desal and not mining the brine.
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.
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.
For the basics, practical engineering did a good video on desalinization: https://youtu.be/mxqOPdEUNTs
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.
Putting together the solar panels, the battery, the desalination plant, and the brine plant, he's proposing a $42 billion dollar project that has only been economically feasible for a year or two now. I'm not surprised that it hasn't been built yet.
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.
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?
https://www.watereducation.org/aquapedia/mexico-and-colorado...
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.
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[1] Source (kind of old): https://www.oas.org/dsd/publications/unit/oea59e/ch20.htm
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.
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.
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.
(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.
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.
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.
Power is easier to transport than water.
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.
"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.
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.
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.
I'll try to find some analyses this weekend if I can.
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.
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.
The gigantic Hambach open-pit mine grows by 0.3km³ a year, so that could take it (but it can't take the Saudi million m³/day plant). By the time the mine is depleted, the resulting 18km³ pit would not be filled by our single hypothetical plant for over 300 years, assuming it won't evaporate. Which leads to:
The evaporation pools might work: they'd "only" have to be 3000 acres (12 km²) to gather the 4GW of solar power at 1kW/m² for 8 hours a day to continuously evaporate that much water daily[2]. Which is certainly large, but not completely impossible. But then there's 2 million tonnes of salt per year which will accumulate continuously over time.
[1] the largest is over a million
[2] not including water not bring a perfect absorber of solar energy or differing insolation
Or, just be the world’s biggest producer of pickles
“ 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.
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?
(1) https://www.wateronline.com/doc/new-10-mile-long-sewage-tunn...
(2) https://www.sandiego.gov/sites/default/files/ploovol4_15.pdf
Pipes tend to last a long time, in large part because it's relatively straightforward to manage the chemistry problem in the pipes.
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...
And despite the initially valid-seeming high hopes for their amazing scholarship, currently it looks that they are too crackpot-y :/
https://www.lesswrong.com/posts/7iAABhWpcGeP5e6SB/it-s-proba...
https://www.lesswrong.com/posts/NRrbJJWnaSorrqvtZ/on-not-get...
Will the contaminant hypothesis of modern obesity be judged true by expert consensus before 2032? 8% yes 92% no
>flaunt its unequaled excellence by exporting alfalfa to all corners of the globe.
really not sure if this is satir.
He literally addresses brine in the article.
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!
> 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.
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.
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.
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.
Between that and the increasing availability of sodium ion batteries it may never actually be economical to mine the Salton Sea, especially considering people actually live nearby and would be affected by the mine; unlike the mines in northern Nevada.
Construction is already beginning.
https://www.usatoday.com/story/news/nation/2023/12/07/lithiu...
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.
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.
On average it's pretty close, but you can definitely get impacts from increased local salinity: https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16859 (just random ecamples)
https://www.scientificamerican.com/article/slaking-the-world... (view in incognito)
That should be an obvious non-starter for anyone remotely familiar with the unique geography and ecology of the area.
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).
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.
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://solarimpulse.com/solutions-explorer/high-efficiency-...
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.
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.
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
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.
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.
The issue is that the American makes it structurally impossible to pass any major reform on any controversial topic.
For your specific idea, the red/blue political map shows you who will probably lose.
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.
Desalination will probably never be worth it from agriculture, but agriculture should survive on the water they can access after people.
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)
More from @dang: https://news.ycombinator.com/item?id=37126175
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...)
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.
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.
Or move to places that don't need them.
https://www.energy.gov/eere/articles/us-department-energy-an...
With respect, why can't we do both?
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.
https://www.nytimes.com/2023/10/03/climate/arizona-saudi-ara...
"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.
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
Here's an alternative proposal based on a sea level canal and tidal power.