How to make data centers less thirsty

This article was originally published by Grist.

Data centers are notoriously thirsty. Researchers at Lawrence Berkeley National Laboratory have found that, in 2023, the facilities consumed roughly 17 billion gallons of water for their operations in the U.S. alone. But that’s only a small part of the picture: A much, much larger share of data center water-intensity is indirect, a byproduct of the facilities’ enormous appetites for energy. That’s because most power plants themselves require huge amounts of water to operate. This off-site, indirect water consumption amounted to a whopping 211 billion gallons in the Berkeley lab’s 2023 tally — well over 10 times the direct on-site usage. As Silicon Valley continues to pour hundreds of billions of dollars into artificial intelligence and demand for data centers grows, these water needs are only going to grow in tandem. 

However, new research from Cornell University shows that there’s a way to mitigate both the climate and water footprints of these facilities: build them in places with lots of wind and solar energy. “Location really matters,” said Fengqi You, an energy systems engineering professor at Cornell and co-author of the new study. Where companies choose to locate their data centers could alter their combined environmental footprints by a factor of up to 100.

In the course of their operations, data centers use water as a coolant. Energy-hungry servers generate substantial heat, and water circulates through cooling systems to prevent the equipment from overheating and breaking down. But substantial amounts of water are also used indirectly through the generation of electricity to run the facilities. Thermoelectric power plants, regardless of whether they use coal, gas, or nuclear material, use that fuel to generate heat that converts water into steam, which is then used to spin a turbine and generate electricity. And since hydroelectric plants typically store large volumes of water in reservoirs behind dams, there is water loss there as well, as water continually evaporates from the surface of reservoirs.

All told, water use during power generation can be responsible for more than 70 percent of a data center’s total water consumption, according to the new Cornell research. “That’s why the electricity power grid mix is very critical,” said You. 

You and his co-authors examined the energy and water use of data centers across the country to project where future investments should be made to reduce environmental impacts. The study assumes that the data center boom, which is being fueled by staggering levels of investment in artificial intelligence, is unlikely to slow down anytime soon. Against that backdrop, the question the study then poses is: Where in the country is the most environmentally sustainable place to build a data center?

The researchers considered both the direct and indirect uses of energy and water as a result of building a data center in a specific location. The most promising region they identified might turn heads: bone-dry West Texas. But because the region is sparsely populated, has groundwater that can be drawn on for use as a coolant, and produces ample wind energy, it scored highest on both energy and water stress metrics. In fact, the grid-related water footprint in West Texas is among the lowest in the country, thanks to the large amount of wind energy produced, according to the study.

“From an energy and water efficiency perspective, the states that have enough dry renewables will be the best choice,” said You, adding that Montana, Nebraska, and South Dakota all appear to be prime locations for future AI servers, alongside the Lone Star State.

Conversely, most parts of the Pacific Northwest didn’t score as well because of the region’s reliance on hydropower. Although the cost of electricity is low in the area, the associated loss of water through power generation means that building more data centers is likely to have a substantially larger water footprint than it would in other parts of the country.

Another recent study from researchers at Purdue University came to a similar conclusion. They looked at the availability of water across the country and mapped out how that might change over time, particularly as climate change makes some regions hotter and drier. The researchers also examined the water impact of existing Google data centers and found that the majority were located in areas with low water stress.

“Companies absolutely take the environment into consideration in their decisions — not just the economic factor,” said Yi Ding, one of the authors of the paper and an electrical and computer engineering professor at Purdue. “We infer that Google already somewhat considered water stress because they put most of the data centers in low-stress regions.”

Texas already has more than 400 data centers located in the state, second only to Virginia. The state’s grid infrastructure, potential for renewables, and availability of cheap land has made it an attractive proposition for tech companies. But the other states identified by the Cornell study as having a small environmental footprint — Nebraska, South Dakota, and Montana — have just 70 or so data centers combined, out of more than at least 4,200 nationally. That’s because a number of other factors, such as the policy environment and infrastructure considerations, are deterring companies from building new facilities there. But if those states geared their policymaking toward attracting data centers, it could make a difference, You said.