I feel like it’s never made clear in what way the water is used up in these cases.

It’s not like it’s consumed like fuel. And it is not absorbed like in agriculture. But I understand it is not trivially recyclable either, the heat of the water alone can be harmful if released as-is. Does cooling happen via evaporation and is that how the water is “lost”? And I am not sure if it is contaminated in other ways.

What is the actual impact or opportunity cost of using the water in datacenter (or energy plant) cooling versus other uses?

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variety8675 6 hours ago | parent | next [-]

Obviously water is renewable, but the constraint here is finite public water system capacity. When that capacity is allocated to data centers less is available for other community needs. See https://arxiv.org/abs/2603.02705

	▲	bayindirh 6 hours ago \| parent [-]
		The water you infuse with biocides is not "immediately renewable". You can't send it to your water management center and just pump back to people.

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bayindirh 6 hours ago | parent | prev [-]

When you're using water in a open-loop data center, you get in cool/cold water, add biocides and other chemicals to protect your infrastructure, then heat it and pump it back to the body of water (i.e. river, lake or an underground hole, or somewhere).

The result is unusable, somewhat toxic (since you can't remove the chemicals), deoxygenated (hot water can dissolve less oxygen) liquid which can't be used for anything, incl. farming or support any kind of life.

It's water, but it's not. It's not suitable for anything. Practically, waste.

If you use heat exchangers and closed circuits in outer loops, you don't waste the water and pump the heat elsewhere, and make that useful. Heat something in the winter, support greenhouses, provide hot water in the building, etc. etc. When you discard the hot water instead of recycling it in closed loop, you make it unusable for anything. From potting it to flushing your toilet. Every possible use case is gone.

If you need a toxic ballast material, maybe you can use it.

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quickthrowman 6 hours ago | parent [-]

> When you're using water in a open-loop data center, you get in cool/cold water, add biocides and other chemicals to protect your infrastructure, then heat it and pump it back to the body of water (i.e. river, lake or an underground hole, or somewhere).

These are not power plants, there are zero data centers using open loop cooling that discharge loop water back into a waterway. It’s unnecessary when you’re cooling a data center.

The system is filled with water and begins operating. As water is lost to evaporation in the cooling towers, more water is added to the cooling loop.

At no point is any of the cooling loop water discharged back into a waterway, it gets recirculated through the system.

All that being said, closed loop cooling is much better in areas with a lack of water.

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bayindirh 6 hours ago | parent | next [-]

I'm not sure, because of two reasons.

First, I don't see the banks of dry coolers or chillers required to cool that amount of water in many of the data center photos.

Second, our closed loop data center is not losing that amount of water, so losing 10 billion gallons of water to evaporation across that many data centers seems unrealistic, even with evaporation for humidity balancing and dry-cooler boosting reasons.

Sitting on top of a data center and directly working on it has its perks, apparently.

	▲	quickthrowman 2 hours ago \| parent [-]
		“Open loop” cooling means there are evaporative cooling towers being used to cool the chilled water loop water: https://en.wikipedia.org/wiki/Cooling_tower Adding evaporative cooling towers to a chilled water loop that uses chillers can double the efficiency. A power plant that draws water from an intake, uses it to reject heat, cools it down, and then discharges it back to the stream/lake/ocean is once-thru cooling.

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oersted 4 hours ago | parent | prev [-]

Well the point of the article is that water usage is much worse in the power plant capacity necessary to feed datacenters.