[Leonard_of_Q]

The tour guide could just give that answer to any such question. It'd be comparable to the answer given to someone who wants to know what that new railroad which was built where there used to be fields or forest is used for: people ride it to go somewhere, freight is passing over it going places.

Having said this I do feel like these data centres should be built in such a way that waste heat is used in some way. Use it to heat structures, greenhouses, whatever. I used to live in a place where a large fraction of the block heating came from a nearby power plant with additional gas-fired heating for when the waste heat wasn't enough. The same can be done with waste heat from data centres by using heat pumps. This can work in colder climates and in the cooler seasons in moderate climates.

[snickerbockers]

I don't think train tracks are comparable because they're effectively one dimensional. You dont need to burn down the forest you just need about 20 feet or so on either side of the track.

WRT the environmental aspect, I think it's patently obvious that nobody who builds these things cares because there are a number of far simpler ways to reduce their footprint which dont get implemented.

Pumping waste heat out to residential heating or some hypothetical industrial application is, at best, just recycling. It only makes sense if you have to accept that the waste inevitably exists whether you recycle it or not, otherwise recycling is never the best way to do anything.

I think there's also inherent risk in building infrastructure that relies on the continual operation of this massive facility that could just as easily be shut down in a few years and written off as a fad. Trusting silly valley to support any product over the long term is never a safe bet.

[mlyle]

Waste heat from power plants isn’t always useful because it is low grade heat… but it is still much, much, much better than the 35-60C water you could get from a data center.

[Leonard_of_Q]

That is what you use the heat pumps for, to transform what you call "low-grade heat" to... "higher-grade heat"?

The COP for a heat pump doing such a transformation can be very high, i.e. for a relatively low power input you get a lot of gain.

[mlyle]

Do the math on pumping 40C water any distance in a loop. It is hard to make it worth it. The water cools off and the pumping takes significant energy, plus the pump and all the piping cost something.

Then using a heat pump on it makes it even worse.

Low grade heat source is not a term I made up- it refers to heat sources under 100C.

Even much hotter low grade heat usually goes unused. You usually need a perfect confluence of a warmer source, very close need for building heat, and a willingness to pay more for environmental friendliness for it all to work out.