this post was submitted on 03 Dec 2024
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[–] [email protected] 6 points 2 weeks ago* (last edited 2 weeks ago) (5 children)

That still leaves the brine problem. Youve just traded one for another.

Hydrogen wouldn't cause another problem.

[–] [email protected] 6 points 2 weeks ago (1 children)

Some could be used in molten salt reactors/batteries, no?

[–] [email protected] 6 points 2 weeks ago* (last edited 2 weeks ago) (2 children)

I imagine so, but were talking about at best case of a 50% water 50% brine solution with reverse osmosis, and worse if it's a thermal desalination plant. It's a fuck ton of liquid, more than we could ever hope to use in a reactor like that.

Some other ideas are evaporate the brine and use the salt for roads in winter, but again, it's more than we could manage at scale, and salting roads isn't ideal either.

[–] [email protected] 4 points 2 weeks ago (1 children)

Are you saying that we could make use of sodium metal for batteries of all sorts at reasonable prices due to it's over abundance by just getting more of it using solar power?

[–] [email protected] 5 points 2 weeks ago* (last edited 2 weeks ago)

I don't know if the output of the desalination is what we actually need or how much refinement it would need, but the salt output would probably still outpace our ability to use it. Sodium is just 1 factor of building these newer batteries.

e.g Tesla has a factory with a 40gwh storage output when fully scaled, and it's taken years to get there. Cells weren't the only factor in that.

[–] [email protected] 1 points 2 weeks ago (2 children)

Yeah, it is a ton of liquid, and I have no idea what the actual amounts look like vs actual uses for salt, such as water softeners (I use exclusively solar salt in mine). I have a hard time visualizing how much salt that actually is, and I haven't looked up the numbers.

Perhaps there's an opportunity for at least one such facility?

[–] [email protected] 2 points 2 weeks ago

Well ya we could definitely use the excess energy to desalinize and then try and find a use for that one plant that handles over capacity. Millions of people rely on it for clean water, but today we mostly just dump it back into the ocean which causes problems and isn't a long term solution.

It's just not a solution to the problem at scale, more like a band aid. But it could buy enough time to build more batteries.

[–] [email protected] 1 points 2 weeks ago (1 children)

I mean if you pull the hydrogen, and are left with brine when the hydrogen is used it will release water, which effectively will get condensated and come back down as rain. Mostly ending up back in the oceans at the end of the day right? Wouldn't that balance out the water to salt ratio at that point if the salt was just added back into the ocean? (Assuming it is dipersed over a longer area. Maybe even just making hydrogen powered ship motors that release the salt back into the water outflowing from the exhaust. Or is it that the chemicals wouldn't form their original bonds, so you may have essentially drain cleaner left over when you are done with the electrolysis?

[–] [email protected] 2 points 2 weeks ago (1 children)

These are two separate processes.

You desalinate ocean water to produce fresh water, which you can use for crops, city utilities, etc. That reduces the strain on local aquifers and reservoirs, especially since California tends to overuse their supply of water (especially poignant for us in Utah; we all rely on the Colorado River).

Hydrogen extraction tends to use pure freshwater to prevent corrosion during the electrolysis process. There has been some research around using seawater directly, but I'm guessing there's still a fair amount of work yet to do this at scale, and I certainly don't think we're there yet for ships.

[–] [email protected] 1 points 2 weeks ago* (last edited 2 weeks ago)

Ah, I missed what you meant, was thinking just use the excess power as fuel for electrolysis to collect hydrogen tanks out at sea, then use that to store it for use in hydrogen based motors on ships or what not, letting the run off water go back into the ocean, hopefully leaving an equal amount of all elements in the water.

But then thought of the bonds

[–] [email protected] 6 points 2 weeks ago

Brine, eh? Well we do grow lots of cucumbers....

;-)

[–] [email protected] 4 points 2 weeks ago (1 children)

Seen some math on the mountains of salt we would have to move. Very discouraging for desalinization and/or getting hydrogen that way.

[–] [email protected] 2 points 2 weeks ago* (last edited 2 weeks ago)

We don't have to get the hydrogen from sea water. It really just depends on where the excess is. Maybe that's not great for Australia or California... but for other places it could be.

[–] [email protected] 3 points 2 weeks ago
[–] [email protected] 2 points 2 weeks ago

Build a salt mine next to the desalinator. Tell them the brine will turn into salt faster than seawater would.