this post was submitted on 11 May 2025
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Interesting concept, but not very scalable. It's basically a reversed dam - when it's full, there's 0m head of water. Then with excess energy, you lower the level inside, storing the energy in the water outside. E.g -2m head. Water then flows in to equalise head, and doing so, regenerates electricity. Adding depth to supercharge pressure differentials is a good idea, although I wonder how they limit the flow rate, or otherwise prevent cavitation shocks each cycle.
Could be useful as a private industrial battery, but a dam would still be better on an infrastructural level.
Dams do have their own significant challenges with habitat destruction and displacing people and silt buildup
Like a battery, it’s not scalable as a one off, but it may be as a modular mass produced item.
Or maybe like a wind turbine. You’d have a field of them comprising a power plant. If you lose some individuals, who cares. If you need to do maintenance you can take one offline or entirely replace it without really impacting the power plants output
An easy manufacturing method would be to 3d print in plastic a double walled shell, with fill holes for concrete, and mounting chanels for motors. Plastic "lining" would provide salt water protection for the concrete.
Dams have issues around silt buildup over time and to the best of my understanding the US is already dammed to the max (within reason).
I'm keen to see how it pans out. Seems like a very interesting concept.
Silt did not magically disappear because your dam is spherical, and there is a lot of it on the sea floor. They need to install some kind of filtering system anyway.
Also, the lifetime of a sphere is estimated to be 60 years, while the traditional dam is engineered for 100+ years of service.
The main advantage is that the sea floor is unused and unregulated like the dry land , but then you could as well build an actual scuba diving underwater base with a hydro dam instead of a sphere, it will also be easier to clean and repair, but I guess that would be too much evil moustache twirling to get funded.
I don't see silt being as big of a problem here, if the intake is located at the top of the sphere that puts it well away from the seabed. The only silt it could suck in is what's dispersed in the water already, and at 500+ meters there's very little current to stir it up. And if they put the intake on top and siphoned the output from the bottom it would even be relatively self-cleaning.
Now imagine this 27 foot wide ball shooting water out of its bottom while on the sea floor and tell me there's still no silt being stirred up. Or algae. Or mineral buildup.
That's why I said siphon it from the bottom, a siphon tube going from the bottom to the top would eject the water up and away while still sucking out most of the sediment that had gotten in and settled on the floor of the ball.
The sediment that gets pushed out into the surrounding water. That gets pulled up with the ball as it creates negative pressure behind it as it rises.
Bro, the ocean is FILTHY. Like, crazy filled with stuff. Like, you could take a coffee filter and pull stuff out filthy. Like the water has so many living organisms in itself it's basically alive.
And let's talk about the salt. Corrosive af salt.
This isn't impossible, but the people trying to point out why this is CRAZY difficult are right. This will not be a set it and forget it scenario by far. It will need regular maintenance. The issue is whether that maintenance is easier or harder than a dam or stationary tank.
Like, why can't we build these in giant freshwater reservoirs? Stick them a pool. Or why does it need to float? Wouldn't a tank at the bottom of a pool with a pump do the same thing? Or two tanks at different heights with a conection between them and a pump? This is just mechanical energy being stored for later. Do the work when it's cheap and reclaim it later.
They don't float, they're fixed in place at depth. They use the pressure of the surrounding water to spin a turbine as its pumped in and out, the only moving parts are the turbine and its associated components. And seeing as how the water is pumped in and out, most of the silt/detritus pulled in during filling, would be pumped out during draining assuming a siphon tube is used to draw the water from the bottom of the sphere (where all the debris settles) to the pump.
Yes salt water is corrosive, but that problem is already solved, there are currently concrete oil platforms built in the 70s and still in service today. We have formulas for concrete that are proven to be seawater resistant.
Building storage tanks on land wouldn't be as efficient due to the greater pressure differential at 500m underwater vs on land. Dams are one of the most expensive structures to build and are very damaging to the surrounding environment. They also have a much larger problem with silt deposition as there is a constant flow of it, every time it rains there's another surge of silt making its way downstream to be trapped by the dam.
Overall this project would be considerably cheaper, more friendly to the environment, and most likely more efficient than any pumped storage on land. And its not like the sea floor is lacking for real estate, unlike any feasable locations for dams here on land.
Did they say it was intended to be on the seafloor? I didn’t see that but assumed it would be moored deep enough for water pressure to turbo boost the turbines, but well clear of silt from the sea floor. That would also be a key benefit if you can moor it at the most useful depth but in any depth of water
The article say about 500/600 meters deep. No mention if on the sea floor or not.
Plus the places most suited for dams also tend to be natural wonders. Rip Glen Canyon and Hetch Hetchy
Or places which are already heavily inhabited/productively used. Inland river valleys are some of the most desirable real estate, in human habitation terms.
Major river dams are often only feasible in countries which either have lots of sparsely populated wilderness (like North America), or which don't have a problem with displacing hundreds of thousands of people and destroying whole communities (like China). Takes it off the menu for a lot of the world.