Liquid cooling loops don't solve the problem of needing to reject the heat to the atmosphere outside of the building. It just makes it more efficient to transport the heat. At the grossest possible definition, a datacenter of N megawatts on Y acres of land is going to emit the same amount of heat whether it's air cooled equipment or liquid is used to take the heat to the outdoor heat exchanging equipment. On the scale of any very large datacenter the heat exchanging equipment is visible from aerial photos (and from space), take a look at google maps for some of the largest hyperscalers for examples.

A few racks or even a couple of dozen racks could be called a datacenter, but nothing on any real scale. Enough to host important and niche things? Sure. I was referring more to like the size of what you might see in Quincy, WA.

For broadly the same reason that many years of heat from braking has heat-saturated the london underground.

https://www.google.com/search?client=firefox-b-d&q=london+un...

You could probably drill sideways into rocks and pump heat into the mountain for a certain period of time, but on a multi-month or year time scale, it would catch up with you after you had saturated it.

There's some 200MW capacity (only 80MW is currently used or being built) data center in a mine near a fjord in Norway. The limiting factor for its capacity seems to be the capacity of the electricity net nearby (which you can just hit and the DC is useless). With how NIMBY Norwegians are there's no way it would ever get to a GW or more even if it might be both technically and economically feasible. That's just one project and can't be replicated anywhere else. It's just a massive advantage that above ground datacenters are relatively 'figured out' and similar everywhere.

edit: 61.9340107, 5.5084207 are the coordinates

Agreed it’s small potatoes, and as a sibling mentions you will still have infrastructure exposed that poses a target to disable the data center, unless you were to drill geothermal and find an underground river to cool it.

Just wanted to make the point you don’t have to pay to excavate the cave :)

Germans hid plane engine factories underground with old (not so efficient) diesel generators running 24/7. 80 years ago, so the tech was leaner. Also they didn’t have issues with ventilation and even today if you don’t know where - you won’t see anything driving around.

That's probably just because there's not much demand for it, not because it's difficult.

There are mines with plenty of space in them, and heat removal can be done with water cooling. But who is going to pay 50% more for that when it isn't needed 99.99% of the time?

The war in Ukraine had showed us that distributed power generation, like solar, and nuclear are most resilient. Nuclear because people do not dare striking the power plants.