How much energy and water does AI really use?

The full story

The episode's narration, word for word. Numbers link to the sources below; timestamps play that moment.

The question 0:00

Last time, we left the courtroom for the machine room. And AI takes something you can touch: electricity, and water. In 2025, Google says its data centres and offices consumed about forty-one billion litres of water, a third more than the year before ¹. So how much energy and water does AI really use?

What we already counted 0:23

Last season, we found a simple text prompt uses roughly a third of a watt-hour, and the world's data centres used about four hundred and eighty-five terawatt-hours in 2025 ^2,3.

Why a computer needs water 0:36

Almost all a server's electricity turns into heat, which has to leave the building ⁴. Many large data centres shed it the way you do on a hot day: by evaporating water ⁴. At thirty degrees, turning a litre of water into vapour soaks up about two thousand four hundred kilojoules ⁵. So carrying away one kilowatt-hour of heat by evaporation alone takes about one and a half litres, by our count ⁵. On cool days, outside air does more of the work ⁴.

Water or power 1:09

Why not skip the water? Some data centres use dry coolers, which need no water on site, but usually more electricity ⁴. Google says water cooling often uses less energy than air cooling ¹. So saving water can cost power, and saving power can cost water ⁴.

The water you don't see 1:28

Withdrawal is water taken from a river or a pipe; consumption is the part that doesn't come back, mostly lost as vapour ⁴. A US government lab estimated that American data centres consumed about sixty-six billion litres on site in 2023 ⁶. The water consumed making their electricity was nearly eight hundred billion, roughly twelve times as much, by our count ⁶.

Litres per kilowatt-hour 1:54

The industry's score is water usage effectiveness: litres of water per kilowatt-hour used by the computers ⁷. Microsoft reports zero point two seven for the year to June 2025, Meta zero point one nine for 2024, and Amazon zero point one two for 2025 ^8,9,10. Google's 2026 report gives totals instead; its AI paper gave one point one five, counting water consumed rather than drawn ^1,11. These are the companies' own numbers, and they count only water used on site ^6,7.

Five drops or three spoonfuls 2:32

In August 2025, Google said its median Gemini text prompt used a quarter of a millilitre, about five drops ¹¹. In June 2025, OpenAI's chief executive Sam Altman put a ChatGPT query at about a fifteenth of a teaspoon, without saying how ¹². In July 2025, Mistral said a few paragraphs from its chatbot used forty-five millilitres, over its whole life cycle ¹³. And a UC Riverside team estimated that an older model, GPT-3, used a half-litre bottle for every ten to fifty answers ⁴. Anthropic, which makes Claude, and xAI have published no such figure ¹⁴.

Counting the edges 3:18

Why the spread? Mostly, where you draw the line ¹⁵. Google counted the cooling water in its own data centres ¹¹. Shaolei Ren, who led that UC Riverside work, says leaving out the power stations' water is "hiding the critical information" ¹⁵. Google says water consumed on site best reflects its effect on local supplies ¹¹. Mistral went back to making the hardware, and had consultants review its study ¹³. Google hadn't put its paper up for peer review, and OpenAI gave no method ^15,12.

The totals 3:55

Google consumed about forty-one billion litres in 2025 ¹. Microsoft withdrew about thirteen billion in the year to June 2025 ¹⁶. Amazon's data centres withdrew about nine billion in 2025, and Meta about five and a half billion in 2024 ^10,9. All four aim to replenish more water than they use by 2030, each measured its own way ^1,8,17,10.

A town in Oregon 4:22

But a total doesn't tell you whose water it is. In The Dalles, a dry town in Oregon, the city went to court, with Google paying, to keep Google's water use secret, then dropped the case in 2022 ^18,19. City records showed Google took twenty-nine per cent of the city's water in 2021 ¹⁹. Google's 2026 report says it consumed about one point eight billion litres there in 2025, and that local sources weren't at high risk ¹.

A suburb in Chile 4:53

In Santiago, Chile, during a long drought, Google planned a data centre in Cerrillos that would use about seven point six million litres of drinking water a day ²⁰. Google later said it would switch to air cooling ^20,21. In February 2024, an environmental court still ordered the water assessment redone, to take climate change into account ^20,21.

Emissions going up 5:18

Then there's carbon. Google says its emissions rose eighteen per cent in 2025, and eighty-one per cent since 2019 ¹. Microsoft's rose twenty-five per cent in the year to June 2025, mainly, it says, from building data centres and from dropping some renewable-energy certificates ⁸. Amazon's rose sixteen per cent in 2025, and Meta's nearly ten per cent in 2024, by our count ^10,9. Yet Google, Microsoft and Meta aim for net zero or better by 2030, and Amazon by 2040; Google now calls that "more complex and challenging than ever" ^1,8,17,10.

Two ways to count 6:00

There are two ways to count electricity emissions. One uses the local grid's average mix; the other subtracts clean energy the company has paid for through contracts and certificates ¹. For Google's 2025 electricity, the first gives about fifteen million tonnes, the second under three million, about a fifth as much, by our count ¹. In 2024, a Guardian analysis estimated that, counted the grid way, the own data centres of Google, Microsoft, Meta and Apple had probably emitted over seven times their official figures from 2020 to 2022 ²².

And those who publish nothing 6:41

At least those four publish figures. In August 2026, Bloomberg reported that OpenAI and Anthropic hadn't disclosed their emissions, made net-zero pledges or published sustainability reports ¹⁴. Both said they were preparing to report under a California law ¹⁴. And in May 2025, researchers led by Sasha Luccioni found eighty-four per cent of AI-model use on one big developer platform ran through models with no environmental disclosure ²³.

The grid next door 7:16

Electricity is local too. In Ireland, data centres used twenty-three per cent of the country's metered electricity in 2025, up from five per cent in 2015 ²⁴. All of Ireland's homes together used twenty-eight per cent ²⁴.

Who pays for the grid? 7:33

Big new users can raise everyone's bills, because more power stations and lines must be built ²⁵. The eastern US grid operator PJM pays power plants to stay available ²⁶. In July 2026, its market monitor said data centres accounted for six point three billion of the sixteen point four billion dollars in its latest such auction ²⁶. A 2024 Virginia review found data centres paying their way for now, but projected that a typical household's power costs could rise by fourteen to thirty-seven dollars a month by 2040 ²⁵.

Promises 8:12

Companies have answered with promises. In January 2026, Microsoft said it would "pay our way" so its data centres don't raise local power prices, and OpenAI made a similar promise ^27,28. In February, Anthropic said it would cover consumers' price increases from data centres built for it; for capacity it leases, it was still "exploring" ²⁹. In March, seven companies, including Amazon, Google, Meta, Microsoft, OpenAI and xAI, signed a White House pledge to pay for new power and grid upgrades ³⁰. Anthropic wasn't among them, and as of October 2026 isn't on the pledge's published list ^30,31.

The air in Memphis 8:57

Power plants can be local, too. Near Memphis, the Colossus data centres built by Elon Musk's AI company run on gas turbines ¹⁴. Bloomberg reported in August 2026 that some lacked clean-air permits, and that Anthropic pays billions to use their computing ¹⁴. In July 2026, xAI says, it agreed a timeline with Mississippi's regulator to remove temporary turbines at one site ³².

Here in Australia 9:28

Here, water is a worry too ³³. In June 2026, a Sydney Water manager said one data centre can need as much water as nine thousand homes ³³. AAP reported Sydney's data centres are set to need about two hundred and fifty million litres a day within a decade: a hundred Olympic pools daily, by our count ³³. In March 2026, the federal government said new data centres shouldn't push up power prices, should use non-drinking water where they can, and should report their water use ³⁴. Those are expectations, not laws, though proposals that ignore them won't be prioritised for federal approvals ³⁴.

New power 10:10

Tech companies are also signing for nuclear power ^35,36,37,38. In 2024, Microsoft signed for power from a reactor being restarted at Three Mile Island, and Google for small reactors, the first planned by 2030 ^35,36. Meta signed for an Illinois nuclear plant's output, and Amazon backed X-energy to add over five gigawatts by 2039 ^38,37. But the International Energy Agency expects renewables to meet about half of data centres' extra demand, and small reactors to arrive only around 2030 ³⁹.

The case for AI 10:45

Now the case on the other side. The International Energy Agency projects data-centre emissions doubling to about three hundred and fifty million tonnes by 2035, around two per cent of the power sector's ³. It also estimated that existing AI tools, widely adopted, could cut about one thousand four hundred million tonnes in 2035 ⁴⁰. But it warned that rebound effects, where efficiency leads to more use, could cancel those savings ⁴⁰. The researcher Hannah Ritchie wrote in 2025 that the carbon footprint of one person's chatbot use is very small ⁴¹. Luccioni's team argues that without disclosure, nobody can check the bigger picture ²³.

So how much? 11:32

So, as of October 2026, how much? Per question, very little, though each company counts differently and most figures haven't been checked by outsiders ^11,12,13,15. In total, it's large, and the reported water and emissions are rising ^1,8,10. And the cost lands somewhere in particular: a dry town, a crowded grid, a city planning for drought ^19,24,33. So can you still tell what's real?

Sources

Every factual claim in the episode is tied to one of these. Spotted an error? Tell us.

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Researched and scripted with AI assistance, fact-checked claim by claim, with synthetic narration and diagrams drawn in code. How we make episodes.