I'll add that it is entirely practical to build a miner (as in chip package) that laughs at water. Power and comms (no serious bandwidth needed, if you recall) through inductive loop.

This is distinct from the earlier 'hedgehog' proposed, in that there is ultimately no naked conductor in the mix at all. (No pcb in the usual sense, etc.) Just a segment of glass pipe with insulated cable wrapped around it.

Anyway : maybe the water is a good idea, but it has some significant problems.

One is that while blessed with a lot of caloric capacity, water also has a significant conductance factor. So, the polyurethane provides a lot of thermic insulation, a large pool of water provides a lot of thermic inertia. These are not at all the same, to better understand this consider the problem of road skidding. If the road is icy, throwing sand on the ice provides a benefit similar to better insulation in our case, whereas increasing the size of the vehicle provides a benefit similar to what you're proposing. Intuitively it's obvious larger vehicles aren't inherently safer, which well illustrates the problem.

The other is that water and electronics don't well mix, and putting a whole lot of water on top of a whole lot of expensive electronics is mechanically unsound, any failure (doesn't even have to be an earthquake) will hit you right where it hurts. This is exactly the sort of bad design that Taleb tends to rail about, and it happens to also be exactly the sort of bad design that caused - or contributed to - Fukushima.

That said, there may be merits to your idea, especially if in a location with good precipitation, where the water cools significantly at night and if you're getting a significantly lower power rate during nigth time (as is often the case around large towns). You could run your thing full blast during night time, throttle it in the day and realise overall better efficiency, perhaps. Kind-of iffy though.

@Anon I am in awe of the realisation of what you're saying there. Yeah, totally, the pre-heated steam is happening.

Sadly, I am also in awe of the realisation of the actual scale of this project. You're right, as designed a hectare of datacenter really needs many square miles of power plant, reducing the entire problem to a very different arrangement willy-nilly. In my defense, I was using using the hectare example to make a point.

However, there would be very good synergies with nuclear plants on site. You could dig the datacenter into the ground rather than having an above ground structure to house it. This would muchly improve your insulation. Placing the nuclear power plants atop 500 tons of HCF-125 kept cool would be a great idea, both for the emergency cooling available through purely mechanical means that can very well be a life saver, and also for the fire supressant properties which idem. All of a sudden it makes sense to buy not 500 tons but ten thousand tons and just keep it there in case there's a malfunction of any kind. If Fukushima had your datacenter under it the Fukushima disaster would have been avoided, at the cost of some lost mining power over a few days.

Another big deal is the heat exchanging. You could use the 1TWh waste heat coming out of the hot side of your compressors to pre-heat the water used in the power plant turbines. This alone would boost efficiency to levels not heard of. Coupled with the fact that because of the geographic arrangement you don't need transformers for transport upping of the current produced, have no wire network to support etc, and the fact that nuclear power is the cheapest power outside of hydro (because of economies of scale the 10GWh plant will probably make electricity cheaper than any hydro plant), this plan would totally kill everyone.

It would also cost more than a small country, what with the billions of dollars worth of miners and the billions of dollars worth of nuclear gear. Nevertheless...

Good plan!