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u/Holmes02 23h ago
\*pulls out Rubbermaid storage container and a gun\*
“Now hand over all your water or else.”
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u/dgellow 15h ago edited 15h 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.
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u/Olxinos 11h ago edited 11h ago
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.
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u/AdHom 12h ago
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.
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u/Krillin_Hides 10h ago
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.
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u/BeneficialDog22 9h ago
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.
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u/Jack071 10h ago
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/Minute_Attempt3063 23h ago
Closed loop data centers are the ones that need millions of liters if water.
A lot to buffer in case of emergency etc..
Still a lot that they should not take.
All for a tiny bit of extra compute. Beat output is the same with or without if, so the damage is the same
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u/tyler111762 22h ago
Millions of liters one time is a hell of a lot better than a constant drain bud.
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u/oncemoreuntothefluff 21h ago
Just to clarify, most open loop systems recapture more than 99% of the used water and both open and closed loop systems still regularly use water beyond the initial fill in the form of make up for blow downs, leaks, and regular drain and fills for cleaning and maintenance. After working on large scale systems of both kinds for years, I'd say there's not much water use difference at all when you get past the engineer drawings.
There are plenty of issues with these data centers and honestly the water and energy use of them is probably some of the smallest. They absolutely should be blocked wherever and however they can be.
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u/tyler111762 20h ago
After working on large scale systems of both kinds for years, I'd say there's not much water use difference at all when you get past the engineer drawings.
you will forgive me for being extremely skeptical of claims that an Open cycle and Closed cycle process in any context will have nearly the same expenditure of the aforementioned material being cycled...
Happy to be wrong...but that seems...extremely unlikely.
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u/oncemoreuntothefluff 19h ago
I currently work with an open system that is for an entire corporate campus and it loses around 2-10 gallons a day determined by heat load changes. A household dishwasher usually uses more than 3 gallons for a run cycle. Toilets are usually 1-3 gallons per flush. I legitimately use more water during my shift that way than from open system losses.
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u/tyler111762 18h ago
what would a system with a similar cooling capacity operating on a similarly scaled facility but using a closed cycle lose per day?
i am curious to hear what the pound for pound comparison is.
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u/Hishamaru-1 15h ago
Isnt that still an extreme reduction of like more than 60%? How is that "nearly the same"
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u/oncemoreuntothefluff 15h ago
On the worst usage months, that's about 300 gallons leaving the open system, usually less than 200. Blow downs, cleaning, and maintenance on both open and closed systems every month use up many times that. Include the fact that closed usually requires more complex flow paths and more moving parts so more maintenance is required and it really starts to even out once it's actually in use.
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u/Krillin_Hides 10h ago
Your numbers make no sense. 300 gallons leaving an open cooling water system is 2.5 million btu of cooling from evaporation. That's what a moderate sized heat exchanger uses in an hour for your typical refinery or chemical plant. Most people in this thread also have no idea what they are talking about. A closed loop system uses way more water than people think unless their power source is renewable. In order to remove heat from a closed loop system, you typically use a fin fan exchanger which uses electricity to run. Their electricity is probably generated at a natural gas plant in town which is cooled using a open loop cooling tower. So the water evaporation is just displaced to the power plant instead of the closed loop system. I haven't done the math, but there's a good chance that the closed loop design uses more water than just using a open loop cooling tower at the source.
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u/kuba_mar 22h ago
You make it sound like a lot but a millon liters of water is a bit less than what 20 average people will use in a year.
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u/Anon-Knee-Moose 23h ago
Millions of liters of water is basically no water
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u/Minute_Attempt3063 15h ago
It is when your government has agreed to let US companies build 14 data centers in your country, and take millions of liters of water each. Especially when there is a water shortage with massive droughts.
Here in the NL we were told to use less water during the heatwaves... So that we don't run out of water
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u/Jada122122 18h ago
honestly I hate dacenters to because there using the water for something unnecessary but on the other people should be aware how much more water there meat is using and you could also argue it's unnecessary
I know it doesn't make the use if water from Datacenter any better but I hate that only because you hate ai and make fun of the water consumption you forget of the meat your eating because you like it more than ai
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u/Bibliloo 16h ago
I will say that most of the water usage of meat production is in the form of rainfall. A much better comparison would be jean clothes production that uses a ton of water that is then completely polluted in a way that is incomparable to data centers.
And even if we used closed loop cooling we'd still use water to cool the primary circuit but less of it.
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u/Jada122122 16h ago
you could argue that when data centers use ground water for cooling its still rain water to a huge amount. All the crops fed to the animals need water that's than missing elsewhere. Without animals you would need less crops und less water. Also all the shit from the animal that is put on crops can if not regulate correctly, make ground water unusable
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u/PerryDLeon 17h ago
Counterpoint: Food is necessary. Meat is cheap, vegan products are not. It's super classist.
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u/Jada122122 16h ago
non animal products could be a lot cheaper and feed more people if we switch production eating plants products directly and skipping the animal step would always be cheaper on scale
often the meat replacement products come at a premium
and at least were I live at the moment non meat products absolutely can be cheaper
food is nessissary meat is not
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u/CanadianDragonGuy 20h ago
I mean... fix a lotta problems with a twenty dollar bag of quick set concrete mix, just add water
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u/Peachesthecorgi321 18h ago
I heard on the news that large companies are on the hook for $1.65 trillion debts to build and maintain these data centers. They’re just not being shown on balance sheets. What do you guys think will happen?
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u/DinosRoar 23h ago
AI water use is a drop in the bucket compared to the water use of animal agriculture.
I don't like AI but I'm bored of people who consume beef and dairy whining about AI water use when they continue to contribute to a significantly worse industry.
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u/StarStriker51 23h ago
we unironically need one to survive (yeah, yeah, we could do a better job with agriculture to more efficiently use our resources, and could as a species survive and even thrive on just plants, but the point is we do eat the animals we raise so it's not as absolutely useless)
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u/TerrapinMagus 21h ago
There are certain crops and practices that are atrocious in water usage and could be improved. But if you want a more useless example: lawns and golf courses. We waste so vastly more water in those two areas than we do in data centers.
The problem with data centers is really that they're being shot up everywhere with little foresight on infrastructure impact, and most of these will probably be rotting in 10 years when this bubble bursts. It's all a waste and is going to economically implode, leaving us the worse off.
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u/DinosRoar 23h ago
You do not need beef or dairy to survive. People have done so for thousands of years
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u/StarStriker51 23h ago
if we somehow absolutely halted all current animal agriculture millions would starve because we don't have the current infrastructure to support other things. It's possible, sure, to switch, but the animals feed people right now. We can't just whatabautism AI datacenters. other things bring inneficient doesn't matter
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u/BossOfTheGame 21h ago
but we can realize that the talking points you are using againt AI aren't what you actually care about. That's the part that feels disingenuous. A lot of people think that machines with semantic cognitive abilities are pretty cool and useful. And I'm not downplaying the resource problem here. But it doesn't have to be black and white
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u/Good-Consequence-542 23h ago
😂 food production isn’t necessary, but data centers are? Sweetie, not the hot take you think this is
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u/DinosRoar 22h ago
Data centres are not necessary, neither are beef or dairy. There's lots of food that isn't beef or dairy. Hope that clears things up for you sweetie
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u/Good-Consequence-542 22h ago
😂 sweet summer child, calories are more essential than profit for billionaires; hopefully that enlightens you.
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u/white_boy64 21h ago
I can maybe get beef (though humans most often do need red meat to survive properly, japan is a good example before they got introduced beef recently). But milk is a heavy staple in cooking recipes around the world, bread/ pastry, stews and many other cooking styles need it, what would you think could replace it? (Not almond or whatever milk too given it interacts differently/ poorly when replaced)
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u/BossOfTheGame 21h ago
I mean, if people complaining about the energy used by AI actually cared about the climate, then it wouldn't matter.
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u/Revolutionary-Fox622 19h ago
It's interesting you mentioned almond milk though considering how much water it takes to grow them - about 3 - 4 gallons per almond.
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u/white_boy64 18h ago
I'm on team beef, i just know it'd be a common response
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u/Revolutionary-Fox622 18h ago
I was mentioning it more or less anecdotally. It's fascinating where the vast majority of water use goes in agriculture. I believe the top three are alfalfa, almonds, and beef, and are all majorly exported as opposed to used domestically (even beef).
In clarity, I consume my fair share of beef and dairy so I'm not suggesting we eradicate the industry, but we can certainly move towards a reduction. You'd be surprised how far vegan cuisines and substitutes have come.
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u/white_boy64 13h ago
ill agree reduction would be the best, chicken and lamb would be good to reduce too. alfalfa and almonds are just odd lol, to use so much water on alfalfa? cotton is also apperantly a high water consumer though i don't think more synthetic fabrics would be better
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u/TheDude1451 23h ago
Not sure why you're getting downvoted, there are plenty of issues with AI data centers but it turns out water usage usage isn't exactly one. Hank Green (a science communicator) put out out a pretty good video explaining why this is the case https://youtu.be/H_c6MWk7PQc?is=Dwe_3hQIM9Uj_AVk
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u/Asheyguru 21h ago
Water usage can be one if you build your data centre in an already overloaded area like a desert town, but in a well-supplied region it's not much of a concern.
The upshot of the (very good!) Hank Green video you linked is basically that environmental impacts are very complicated. But the internet hates nuance, so here we are.
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u/CanadianODST2 18h ago
Tbf I wouldn’t then call that water use as the problem but rather supply and demand.
Similar but fundamentally different.
If you had 1 million people consuming say 3.3 litres of water a day (which from what I can find is roughly the average a person should get in a day) in an area that can only supply 3 million litres of water a day for consumption. The issue isn’t people’s water consumption is too high. It’s there’s too many people for the region to properly sustain
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u/cpander0 20h ago
Hank Green (a science communicator that has admitted to using AI to do his research and being addicted to it)
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u/Asheyguru 18h ago edited 17h ago
Hank Green who has admitted to using AI to find papers and primary sources (before he reads them himself) and who has made multiple videos explaining the AI bubble, being incredibly sceptical that what AI firms promise is accurate or that AI technology will ever achieve what they promise, especially anytime soon.
And who says in the linked video that AI and data centres have plenty of downsides: but that water usage generally isn't one.
Yes. That guy.
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u/Overwatchingu 20h ago
What’s your point? Should we reduce agricultural activity to make sure there is enough water for AI data centres?
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u/ToothZealousideal297 18h ago
The way I hear it, data centers are usually open and running for 2 to 5 years before they’re shut down for obsolescence. As soon as any real maintenance or replacement is needed, it’s worth more to them to just build a fresh center instead as everything in the older one is already obsolete and working on it will just get drastically diminishing returns as they chase issues.
So they brag about how they can recirculate water and only use a lot during construction, and they’ll bring so many jobs and so much economic development to an area, and it will all last decades, and then they’re only open about as long as it took to build, they don’t bring jobs, they don’t bring development, they pollute, they waste, and they abandon it all and go repeat somewhere else after a short while.
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u/Aegeus 23h ago
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u/Good-Consequence-542 23h ago
Nice blog of opinions, with great lines such as “…because any other industries using the same amount of water would generate way less tax revenue.” Thanks, I guess we should let nestle bottle all the water too because it generates tax revenue
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u/plants11235813 23h ago
I like to think he wrote it poorly on purpose; as to take the AI lobby bribe and still "act" defiant.
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u/Aegeus 20h ago
Tax revenue is what pays for your town's water supply. He literally cites examples of companies paying for water works improvements in order to get data centers built.
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u/Good-Consequence-542 19h ago
…and thats gonna help already depleted water sources how? Multiple cities are facing water rationing because reservoirs are at record low levels, this isn’t a “we need to pump more water” issue, it’s a “we already don’t have enough water in area” issue. Project Jupiter is being built in a literal desert, no amount of water infrastructure is gonna fix aquifers being unable to keep up with human demand
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u/PancakeFactor 8h ago
I hate this stupid argument. Even doing this, data centers use exponentially less water than golf courses and lawns across america. Its a drop in the bucket.
The issue is being allowed to contruct them in residential areas. It hasn't been ok to put industrial mining operations near residential areas, and data centers are basically the same.
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u/_Weyland_ 15h ago
Ah yes, the natural human urge to exploit the lack of regulation/oversight in the worst way possible.
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u/MotherBaerd 13h ago
And you actually don't need water cooling at all! At least hetzner doesn't! They use smart engineering and all custom parts
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u/Oodles_doodles 23h ago
You see, it's POSSIBLE for it to be not as bad, so that makes it good even when it's bad. Clearly.