The West is parched, and getting more so by the day. Lake Mead — the country’s largest reservoir — is nearing “dead pool” levels, meaning it may soon be too low to flow downstream. The entirety of the Four Corners plus California is mired in megadrought.
Amid this desiccation, hundreds of the country’s data centers use vast amounts of water to hum along. Dozens cluster around major metro centers, including those with mandatory or voluntary water restrictions in place to curtail residential and agricultural use.
Exactly how much water, however, is an open question given that many companies don’t track it, much less report it. While their energy use and accompanying emissions have made more headlines, data centers’ water usage is coming under increasing scrutiny. And as climate change makes water more scarce, pressure could grow on hyperscale data centers to disclose their water use and factor scarcity into where and how they operate.
Centers consume water both directly (for liquid cooling) and indirectly (for non-renewable electricity generation). Roughly one-fifth of the data center servers in the U.S. source water directly from moderately to highly water-stressed watersheds, according to a 2021 analysis published in Environmental Research Letters.
“There’s a trade-off between energy efficiency and water use” in terms of how a company cools a data center, said Arman Shehabi, a research scientist at Lawrence Berkeley Lab and one of the study’s authors. He said water availability is likely low on the priority list when companies are deciding where to build compared to the price of electricity.
Drought, and specifically the ongoing megadrought in the West, is “pretty new on the radar” of these companies, said Shehabi. In recent decades, many data center companies moved toward using water rather than electricity to keep servers cool in a bid to keep energy use and emissions down, he added. But it is becoming increasingly clear that water is a potentially scarce resource in many regions as well.
The megadrought gripping the West is the worst since at least 800 A.D., and climate change is increasing the odds of more dry weather to come. Other parts of the world are also increasingly water-stressed due to the impact of climate change as well as people relying more heavily on groundwater for everything from drinking to agriculture.
While these other uses tend to be meticulously measured, data center water use is much more opaque, a fact that has already led to tension on the local level between companies and communities that have been asked to cut their use in times of drought. The Uptime Institute, which advises the information technology sector on improving infrastructure performance and efficiency, found in its latest Data Center Industry Survey that just 51% of the respondents measure water use in some way, even as energy use and emissions tracking becomes standard fare.
“There is very limited data available on data center water consumption,” said David Mytton, who authored a 2021 NPJ Clean Water article on the subject. As compared with energy use, he continued, “water consumption is much more behind-the-scenes, is much more controversial, and in some cases is considered, or has been considered in the past, a trade secret.”
Few hyperscale data center owners publicize their total water use data, and it’s even harder to find information on specific data centers. Still, there are some signs of progress as companies increasingly consider not only how their operations impact the climate, but also the reverse.
Microsoft has begun sharing its aggregate consumption in its annual sustainability reports. The 2021 installment shows that the company’s appetite for water has grown steadily over the last five years, from roughly 67.5 million cubic feet in 2017 to just over 158 million cubic feet in 2021. The company has increased the volume of water it replenishes in that period as well, from none in 2017 to roughly 71 million cubic feet in 2021. The company aims to increase replenishment to the point where it outstrips its water consumption by 2030, and reduce data center water waste by 95% by 2024.
Noelle Walsh, corporate vice president of Microsoft’s Cloud Operations and Innovation team, said the company is looking into “new, waterless cooling solutions, such as two-phase liquid immersion cooling” to help reach these goals.
Microsoft’s main competitors — AWS and Google — are at least tracking water data for internal use. Google has also set a water stewardship pledge, saying it will replenish 120% of the water it consumes by 2030. Neither of the two, however, responded on the record to questions from Protocol about how much water their data centers consume.
And while AWS has not committed to a certain timeline, it has stated publicly that it is working to use water more efficiently and use less potable water to cool its data centers. A spokesperson said that while the company tracks its own water use, it has not had to cut back as a consequence of the West’s drought.
Arno van Gennip — the vice president of Operations Engineering at Equinix, a digital infrastructure company with more than 240 data centers globally — said that measuring water is still a fairly new phenomenon because, quite simply, water has historically been both abundant and cheap.
However, measuring water use is an increasingly crucial part of making data centers more efficient. “If you don’t measure, you cannot manage,” van Gennip said.
While many of Equinix’s centers were already tracking use, the company began doing so across the board last year. It is in the process of analyzing that data for accuracy before publicly sharing it, van Gennip said.
Water usage effectiveness has emerged as a metric used to gauge efficiency, and is calculated by dividing the total liters of water used for humidification and cooling by the total annual amount of power used by the center. While water usage effectiveness was inspired by the now-widespread metric of power usage effectiveness, Shehabi said it has yet to catch on in the same way.
“You’ve got to have some sort of efficiency metric before anyone starts working to improve on it. And that’s happening with energy use, at least on the cooling side … but we haven’t quite seen that with water,” he said.
But change might be afoot, at least when it comes to factoring drought into data centers’ plans. Van Gennip said that Equinix began considering the subject early in 2021, and is looking into contingency plans for the impacts of both drought and flood.
He predicted that new data centers will consider water access down the road as resources become increasingly precious. “This is one of the areas where we need to be prepared,” van Gennip said.
