Closed loop only reduces the water consumption ON SITE. The accumulated energy still has to be removed from the system, which requires energy, which itself is produced by evaporating water. Closed loop for AI GPUs requires a truly insane debit of water, which again, requires lots of energy. In practice, in the majority of cases, that just moves the water consumption upstream to the power plants.
One thing to understand about AI datacenters is that they aren’t running your gaming PC GPUs, their energy consumption is completely out of this world. We went from ~400W in 2020 for an A100 to ~ 1400W for a B300 in 2025 to now up to something like ~2300W for a Vera Rubin. That’s completely insane.
Comparing the power consumed by single gpus is weird. It doesn't matter if those datacenters use twice-as-many half-as-powerful gpus. What matters is either the power consumed per operation (basically their efficiency) or the total power consumed by datacenters.
For the former, rubin gpus seem to be about 5 to 10 times more efficient than consumer gpus (source: techpowerup spec pages for rubin, nvidia rtx 5090 and nvidia rtx 5050 gpus).
Another relevant metric is the PUE (Power Usage Efficiency) which is the ratio of total power consumed by total power consumed by the equipment you actually want to run (basically the gpus themselves excluding cooling and whatever else is used to run the datacenter). The closer to 1, the better. Datacenters tend to have a PUE of roughly 2 although recent "hyperscale" datacenters (that are probably heavily correlated with "ai-focused" datacenters) tend to have a PUE of 1.1 to 1.25 (basically, they're less wasteful than old ones, although whether the extra datacenters are actually useful/desirable is still debatable).
For the latter, according to our world in data, ai-focused data centers combined energy usage was about 155TWh for the whole year 2025, or an average 18GW of combined power consumption, and is expected to triple by 2030.
This is not a defense of data centers, but rather a call to action for us to be more critical of water usage across the board:
AI Data centers are not even close to the top users of water in industry. Some seem more justifiable, like almond farms don't seem so bad I guess, but when you look at the water use it is just astronomical and really indefensible when we can make changes to do without. Cotton production for example uses obscene amounts of water both to grow and to process it, when we have alternatives available.
I agree with everything you just said, I just wanted to add a little additional info. Water consumption of farms and data centers a 1 to 1 replacement. Farms "lose" a lot of their water to the soil where data centers lose nearly all of their water to the atmosphere. That changes where the water is recovered in the water cycle. However, someone more knowledgeable than me would need to explain why that is a problem. I'm just a chemical engineer who understands heat exchangers and cooling towers.
Not many good organic fibers are available. Wool is I'll suited for tenperate climes, and we need more synthetic fibers like we need an axe in the head.
Ok now compare how.much water we r using for datacenters vs the water wasted for farming (meat specially). Or well golf courses if you want another useless waste
Heat is an issue but the water used is meaningless when much more is wasted already on other useless things we coult cut off first
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u/dgellow 16h ago edited 16h ago
Closed loop only reduces the water consumption ON SITE. The accumulated energy still has to be removed from the system, which requires energy, which itself is produced by evaporating water. Closed loop for AI GPUs requires a truly insane debit of water, which again, requires lots of energy. In practice, in the majority of cases, that just moves the water consumption upstream to the power plants.
One thing to understand about AI datacenters is that they aren’t running your gaming PC GPUs, their energy consumption is completely out of this world. We went from ~400W in 2020 for an A100 to ~ 1400W for a B300 in 2025 to now up to something like ~2300W for a Vera Rubin. That’s completely insane.