A vision for the alleviation of water scarcity in the US Southwest
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A vision for the alleviation of water scarcity in the US Southwest
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Re: A vision for the alleviation of water scarcity in the US Southwest
#2Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?
Re: A vision for the alleviation of water scarcity in the US Southwest
#3Apart 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.
Re: A vision for the alleviation of water scarcity in the US Southwest
#4Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?
If efficiency is the metric you're going for, move the people and do nothing. It's probably what will happen eventually anyway.
Re: A vision for the alleviation of water scarcity in the US Southwest
#5Apart 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…
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.
Re: A vision for the alleviation of water scarcity in the US Southwest
#6Apart 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…
> 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.
Re: A vision for the alleviation of water scarcity in the US Southwest
#7Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?
If efficiency is the metric you're going for, move the people and do nothing. It's probably what will happen eventually anyway.
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.
Re: A vision for the alleviation of water scarcity in the US Southwest
#8Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?
If efficiency is the metric you're going for, move the people and do nothing. It's probably what will happen eventually anyway.
Moving 50 million people seems to me to incur more effort than building $10b of solar
Re: A vision for the alleviation of water scarcity in the US Southwest
#9Would it be more efficient to use solar thermal for some of the desalination instead of $10b worth or regular solar?
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
Re: A vision for the alleviation of water scarcity in the US Southwest
#10So 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...)