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Comment by lazide | Hacker News Reader

That depends on the geography.

Bangladesh, The Netherlands, Kansas, maybe Texas, etc? No, not useful.

Norway, Wyoming, Idaho, California, Switzerland, Nevada, Arizona, etc.? Oh yeah. Very doable.

My personal pet idea: a big ‘tower’ on the seafloor. Yes, costs are immense, but scaling would really work well. (Making the ‘well’ or tower twice as big would not make the cost double).

In ascii art:

   ———|  |——

      |  |                       

      |++|

With ‘| |’ the walls of the well or tower, —- the sealevel, and ++ the water inside the well. Energy would be gained through letting seawater go ‘into’ the well/water tower. (Edit: attempt to make ascii art work)

You don't need a tower. A boat with a winch and a weight does the job cheaply. For extra credit, more weights.

Limited by the displaced water weight. Prone to storm damage. But the general idea could work and you could even do it entirely under water, saving you from having to dig out a mineshaft, just sink a bunch of caissons to create an underwater tower. As long as they stack and can be re-inforced so they don't end up shearing under the pressure of flowing water. Maybe even open up the sides to a lattice to reduce that resistance.

Existing supertankers can displace in the hundreds of thousands of tons. New, they cost under $100M. Scrap, much less.

They are not bothered much by weather, in normal operation. With that much weight hanging well below the surface, they would be very stable. (Racked together side by side, moreso.) Think of it as a very long oil platform. Those endure any weather with no difficulty.

No need for anything attached to the bottom except anchor chains.

When planning ocean operation, make sure almost everything is at or well above the surface, and everything complicated (motor/generator, winch, power conversion) is well protected from exposure. Ocean deployments that expose expensive stuff to wave action or put it underwater fail, reliably. (Expect tidal generation that puts generators underwater to fail spectacularly.)

Offshore wind has the nacelle well encapsulated and everything that moves far above the waves. Nothing is underwater except the pilings, the end of the support post, and a wire.

Yep, I tried to acknowledge that in the original comment when I said it’s geographically dependent.

It still seems like the only solution that currently exists and actually works on the scale required. I’m not sure what realistic solutions are for regions where hydro pumped storage is not a viable option.

A handful of hours storage, 60% curtailment (with most of the surplus used to create hydrogen and such for chemical feedstock) and a small amount of HVDC leaves a remainder small enough that meeting it with biogas and existing hydro is possible, meeting it with hudrogen is not costly, or meeting it with LNG is not a huge problem.

https://www.nature.com/articles/s41467-021-26355-z

The world produces about 3TW of electricity, 2022's battery production was 760GWh and it's growing 30-50% yoy.

Ideally degrowth happens, but while we negotiate that, the |bhattery industry is at the scale required and is rapidly shedding critical mineral requirements (sodium ion is at GWh scale now, and much larger supply chains with all abundant materials come online in june).

> I’m not sure what realistic solutions are for regions where hydro pumped storage is not a viable option.

Pumped thermal.

https://aip.scitation.org/doi/10.1063/1.4994054

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