Wednesday Morning Rant

The UK is in a drought and the government is worried about water availability and is therefore pushing conservation. It's mostly stuff you would expect. Turn off the tap and don't let it leak. Be parsimonious with irrigation. Don't water your lawn. Take less time in the shower. Delete your data.

What's that, you say? Well, from the UK's National Drought Group:

Delete old emails and pictures as data centres require vast amounts of water to cool their systems.

Datacenter capacity exists. It's already built. The water cooling system - if the equipment is water cooled, which it often is - is already deployed. The only way that cooling system can use less water than it does today is if it either gets smaller (e.g., equipment is shut down and the cooling loops servicing it are drained) or if it gets more efficient so it needs less water to keep it cool (that is, it's replaced). It would take a truly staggering reduction in data consumption to result in shutdowns of that much equipment and it would probably just sit there idle for a while since it's already paid for and the owners will find a use for it.

But even that were to happen, it's still a stupid recommendation. First, most data aren't personal data anymore. Everyone's personal photos and E-Mails are a drop in the bucket compared to AI datasets and other large commercial data consumers. But set aside the laughable absurdity and the depth of the misunderstanding this recommendation reflects. Pretend it could matter. If we all get together and delete our family photos, we can shutter a couple of datacenters and avoid the water consumption. How much difference would it make?

Not much. First, "water-cooled" datacenters only use some water. "Liquid-cooled" is probably more accurate. Large-scale datacenter cooling loops have water and (usually) a lot of glycol, along with various additives and biocides. Exact ratios are usually trade secrets, but there is a fair amount of non-water in a "water-cooled" datacenter. But again, let's pretend there isn't. It's all water straight from the tap. How much water are we talking about?

Again, it's hard to say. It isn't one size fits all. But let's take an extreme case. The US Department of Energy's "El Capitan" supercomputer at the Lawrence Livermore National Laboratory is the fastest system in the world, and came online late last year. It uses an elaborate - and big - water cooling system that requires, according to PC Magazine, nine million gallons of water "per day." That's how much cycles through it per day, not it's daily consumption or the size of its reservoir. These are closed systems. There are always losses - leaks, evaporation, etc. - but water doesn't just flow through the datacenter on its way down the drain. So let's make some very bad assumptions. Let's assume that "El Capitan" has a nine million gallon reservoir, and that reservoir gets fully consumed over the course of a year.

So that would mean that the datacenter requires nine million gallons of water per year to run - certainly overstating it, probably by at least an order of magnitude. Your average four-member British household uses 450 liters of water per day, which comes out to about 43,224 gallons per year. The nine million gallons that would be saved by shutting down the datacenter that holds the world's most powerful supercomputer would save the equivalent of about 208 average four-person households. Even if you can completely shutter a dozen "El Capitan"-sized datacenters thanks to deleting your pictures and E-Mails, you're saving much less water than a neighborhood in London uses up in a year.

It's one of the most laughably stupid things I have seen in a long time. It exposes the fundamental misunderstanding of policymakers. They don't know how anything works. Datacenter water usage, in aggregate, is non-trivial but encouraging people to delete their E-Mails and photos would do precisely nothing to curtail it, anyway. That stuff is small change in a world where AI is a thing. The only thing this recommendation is good for is a hearty laugh. Or deep contempt because no matter what, bureaucrats always find a way to recommend something you'll hate that also happens to be pointless.

I'm used to my own government publishing insane nonsense like this, so it's almost refreshing to see it come from somewhere else this time.

posted by Joe Mannix at 11:00 AM

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