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Earlier this year, e-commerce company Amazon won approval to open two new data centers in Santiago, Chile. The $400 million project marks the company’s first attempt in Latin America to build data facilities that use huge amounts of electricity and water to run cloud computing services and online programs, and has led residents to protest the industry’s expansion in one of the world’s most water-scarce countries.
The tech giant made another related announcement this week: It plans to invest in water conservation along the Maipo River, the main water source for the Santiago region. Amazon is partnering with a water-tech startup to help farmers along the river install drip irrigation systems on 165 acres of farmland. The plan, which will save enough water to supply about 300 homes per year, is part of Amazon’s campaign to make its cloud-computing business “water positive” by 2030, meaning its web-services division will conserve or replenish more water than it consumes.
The reason behind the water commitment is clear: Data centers require huge amounts of water to cool servers, and Amazon plans to spend $100 billion over the next decade to build more data centers as part of a big bet on its Amazon Web Services cloud-computing platform. Other tech companies, including Microsoft and Meta, which are investing in data centers to support the artificial intelligence boom, have made similar water pledges amid growing controversy over the sector’s depletion of water and power.
Amazon claims that its data centers are already the most water-efficient in the industry, and that it plans to roll out additional water-saving projects to mitigate the water shortage. But like any corporate pledge to achieve “net-zero” emissions, these water pledges are more complicated than they appear at first glance. While the company has certainly taken steps to reduce water use at its facilities, its calculations don’t take into account the massive water demands of the power plants that power those very facilities. Without a larger effort to reduce the underlying strain Amazon places on the power grid, water-saving efforts by it and other tech giants will only solve part of the problem, according to experts who spoke to Grist.
The powerful servers in large data centers run hot as they process unprecedented amounts of information, and they require both water and electricity to keep them from overheating. Rather than trying to keep these rooms cool with traditional air conditioners, many companies use water as a coolant, running it through the servers to cool them. The centers also need a lot of electricity to run all those servers: Servers already account for about 3% of U.S. electricity demand, and that number could more than double by 2030. On top of that, the coal, gas, and nuclear plants that produce that electricity Themselves Drink plenty of extra water to stay cool.
Will Hughes, head of water sustainability at Amazon Web Services, told Grist that the company uses water in its data centers to conserve energy-hungry air conditioning units and reduce reliance on fossil fuels.
“Using water for cooling in most locations would significantly reduce the amount of energy we use, which helps us achieve our other sustainability goals,” he said. “While you can always choose not to use water for cooling, we would like to do so heavily given the energy and efficiency benefits.”
To save on energy costs, the company’s data centers must evaporate millions of gallons of water per year. It’s hard to say exactly how much water the data center industry consumes, but the rough estimates are substantial. According to one 2021 study, U.S. data centers consumed about 415,000 acre-feet of water in 2018, even before the artificial intelligence boom. That’s enough to supply about one million average homes for a year, and roughly the amount of water that California’s Imperial Valley withdraws from the Colorado River each year to grow winter vegetables. Another study found that data centers operated by Microsoft, Google, and Meta pump twice as much water from rivers and aquifers as the entire country of Denmark.
AI programs such as ChatGPT require huge amounts of server space, so this figure is almost certain to have ballooned in recent years as companies build more centers to accommodate the artificial intelligence boom. Technology companies have built hundreds of new data centers in the past few years alone, with hundreds more planned. Recent estimates suggest that ChatGPT requires one average-sized bottle of water for every 10-50 chat responses. The amount of water consumed in any one of these companies’ data centers could now rival a major beverage company such as PepsiCo.
Amazon doesn’t release statistics about its water consumption; Hughes told Grist the company is “focused on efficiency.” But the tech giant’s water usage is likely lower than some of its competitors. One reason is that it builds most of its data centers with so-called evaporative cooling systems, which require much less water than other cooling technologies and kick in only when temperatures get too hot. The company estimates its water usage at about 10% of the industry average, and in warmer regions like Sweden, it doesn’t use water to cool its data centers except during the hottest summer months.
Companies can reduce their environmental impact by building AI operations in temperate regions where water resources are plentiful, but they must balance efficiency concerns with concerns about land and electricity costs, as well as the need to be located close to key customers. A recent study found that water consumption at U.S. data centers is “disproportionately distributed in water-scarce basins” such as the Southwest, but Amazon has concentrated much of its operations in the East, particularly Virginia, where electricity is cheap and offers financial incentives to tech companies.
“Many stores are run by customer needs, [prices for] “We want to conserve real estate and power,” Hughes says. “Most of our data centers are in areas that aren’t too hot and where there’s not a lot of water. Virginia and Ohio get hot in the summer, but they don’t need to use water for cooling most of the year.” Still, the company’s expansion in Virginia is already raising concerns about water supplies.
To mitigate these impacts on watersheds, the company also funds dozens of conservation and recharge projects, such as in Chile. The company donates recycled water from its data centers to farmers, who use it to irrigate crops. It also helps restore rivers that supply water-scarce cities such as Cape Town, South Africa. And in Northern Virginia, it’s working to install cover crop fields that can reduce runoff pollution into local waterways. The company treats these projects the same way other companies treat carbon offsets, calculating each gallon recharged against each gallon consumed by its data centers. In its latest sustainability report, Amazon said it is 41% toward its goal of being “water positive.” In other words, the company funds projects that recharge or conserve just over four gallons of water for every 10 gallons it uses.
But despite all this, the company’s water management goals don’t include the water consumed by the power plants that supply its data centers, which can be three to 10 times more water consumed on-site at the data centers, according to Xiaolei Ren, an engineering professor at the University of California, Riverside, who studies data center water use. As an example, Ren pointed to Amazon’s Pennsylvania data center, which relies on a nuclear power plant less than a mile away. The data center uses about 20% of the power plant’s capacity.
“They say they use very little water, but there’s a lot of water evaporating nearby that powers the data center,” he said.
Companies like Amazon can reduce this secondary water use by relying on renewable energy sources that don’t require as much water as traditional power plants. Hughes said the company has sought to “reduce” both its water and energy needs through another goal: to run on 100% renewable energy, but Wren noted that Amazon’s data centers require 24-hour power, meaning there are limits to intermittently available renewable energy sources like solar and wind farms.
Amazon isn’t the only company tackling this issue: Another major data center company, CyrusOne, revealed in a sustainability report released earlier this year that it uses more than eight times as much water to power its data centers than it uses on-site.
“To the extent that we rely on the electric grid, including thermal sources, to power our facilities, we are indirectly responsible for the significant consumption of water in the production of that electricity,” the report states.
Even replenishment projects like the one in Chile are only partially helpful in mitigating the impact of the data center explosion. Amazon’s cloud business has projects in many of the same basins where it has data centers, and even though it is “water positive” globally, that doesn’t mean access to water in any particular basin will remain intact. The company’s data centers and power plants may be pumping more water than the company replenishes in a given area, and replenishment projects in other aquifers around the world cannot address the physical impacts of that particular overpumping.
“If they can capture some of the water resources, purify it and return it to the community, that’s better than nothing, but I don’t think it’s going to reduce actual consumption,” Wren said. “It masks a lot of the real issues because water is really a local issue.”
Fix: This story has been corrected to clarify that Amazon’s “Water Positive” pledge applies only to its Web Services division.
This article originally appeared on Grist. Grist is a nonprofit, independent media organization dedicated to telling stories about climate solutions and a just future. For more information, visit Grist.org.
