Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

caseyhandmer.wordpress.com

Post reply on HN
Print view View original

121–130 of 161 posts

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

#121

Post by llsf »

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.

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

#122

Post by skywhopper »

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.

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

#123

Post by palmfacehn »

bobthepanda wrote: post #120
zbrozek wrote: post #5

Earlier quoted context omitted.

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.

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.

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.

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

#124

Post by adrianmonk »

warcher wrote: post #115
amluto wrote: post #113

Earlier quoted context omitted.

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 = atmospheri…

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…

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.

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

#125

Post by skywhopper »

cs702 wrote: post #24

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 ser…

His calculations are off by much more than a factor of 2. Maybe two orders of magnitude.

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

#126

Post by warcher »

adrianmonk wrote: post #124
warcher wrote: post #115

Earlier quoted context omitted.

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…

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…

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.

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

#127

Post by bobthepanda »

palmfacehn wrote: post #123
bobthepanda wrote: post #120

Earlier quoted context omitted.

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.

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.

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”

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

#128

Post by rindalir »

joescharf wrote: post #38

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 econ…

I am really appreciating the IANAH and TINHA side effects of your post :)

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

#129

Post by Accujack »

margalabargala wrote: post #82
obblekk wrote: post #57

Earlier quoted context omitted.

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 wor…

> 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 f…

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.

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

#130

Post by photonbucket »

digging wrote: post #108
konschubert wrote: post #93

Earlier quoted context omitted.

Brine is just concentrated seawater. What waste products?

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.

The pipe should really go a dozen miles out to sea and then get pump-mixed with the destination water
Post reply on HN