Stupid question: datacenters need water for cooling right? But they don't boil that water, ie it comes out of the datacenter just a little warmer? If that is the case does it matter to the city? The warmer water can still be used for agriculture or any other common usage.

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Ekaros an hour ago | parent | next [-]

There are multiple ways. Closed loops, well not big deal you fill up and there is slight evaporation losses, but you could ship that in in tanker truck maybe once every few years.

Next is open loop cooling using secondary loop. Take a river, lake or sea. Pump some water from it, pass through heat exchanger and pump back out. Manageable for most of the year. Worse version is pump ground water and return it to these. Depletes the ground water...

And finally evaporative cooling. Which is boiling, but not at boiling point. Water goes to sky. No immediate return to local ground water or downstream the river... In this case you actually do in sense use up the water. Kinda like burning fossil fuels returns co2 to atmosphere. It will later turn to biomass, but that is a separate cycle.

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jacquesm 2 hours ago | parent | prev | next [-]

It's not a stupid question but: technically, after passing through Google's facility that is now gray water, and you can't use that for agriculture or any other 'common usage' without a whole raft of work and you can't just dump it into the aquifer either.

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cm2187 2 hours ago | parent | next [-]

But if it just went through some heat exchangers, it's not like if it was dirty? As far as I know, nuclear power plants return the water they consume to the rivers they extracted it from.

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jacquesm an hour ago | parent [-]

Heat exchangers could easily contaminate the water. If they're not kept hot enough they could be breeding ground for Legionella and a whole raft of other bacteria. Clean water is science, not just a matter of bulk pumping stuff from one place to another (though that's definitely a part of it). Water treatment plants are complex and have a ton of QA on their product. You can't just run it into a factory and pretend it is the same stuff going in modulo some increase in temperature.

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cm2187 an hour ago | parent [-]

But you are talking about drinking water. I would be surprised if they even use that for cooling. But any non human consumption use of water (like agriculture) should happily use that water, shouldn't it?

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jacquesm an hour ago | parent | next [-]

No, agriculture has fairly strict standards about the quality of the water, they can't use gray water to irrigate. Of course it will still work but depending on where you live the produce may then no longer be fit for human consumption.

You can use it for irrigating your lawn but not for vegetables, especially not if you plan on selling them. But 'light' gray water requires relatively little treatment before you can use it again, however this could still be quite expensive compared to just letting it go. I wonder if they've done any quantitative research on this that's public.

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schainks an hour ago | parent | prev [-]

This is America. Our toilets use _clean potable water_ to flush our shit.

Drinking water from the mains is metered, so it is observable from the business perspective. Life finds a way. Heat exchangers and datacenter plumbing absolutely breed life and put things into the water that were not there when it was pumped in.

Imagine if a datacenter used a shady supplier of pipe that used, say, lead in their alloy. Do you want that datacenter grey water going into crops?

	▲	cm2187 39 minutes ago \| parent [-]
		The water from the lake isn't drinking water either, it is contaminated with all sort of stuff including dead animals and animals excrements. But it doesn't mean it is not suitable for agriculture.

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DanielHB 2 hours ago | parent | prev [-]

Don't they reuse the water by cooling it outside the data center? Most power plants do that.

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jacquesm 2 hours ago | parent [-]

Yes, but that does not mean it is now clean water. Anything could happen between the moment Google ingests it and spits it back out, the assumption that it is 'just' a little warmer is nice but it misses the option of for instance contamination from a secondary circuit or various substances leaching into the water used as a coolant.

	▲	chinathrow 19 minutes ago \| parent [-]
		So where toes the "not clean water" go then usually in such a setup?

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nonfamous 2 hours ago | parent | prev [-]

A lot of it gets converted to water vapor in the evaporative coolers, so it doesn't flow out -- it becomes humidity or clouds. The coolers do also produce waste water, but with all the minerals left behind after evaporation it's not suitable for drinking.