TECH

What can quench the thirst of AI data centers?
Data centers have a thirst for water, and their rapid expansion threatens freshwater supplies. Only 3% of Earth’s water is freshwater, and only 0.5% of all water is accessible and safe for human consumption. Freshwater is critical for survival. On average, a human being can live without water for only three days. Increasing drought and water shortages are reducing water availability. Meanwhile, data center developers are increasingly tapping into surface and underground aquifers to cool their facilities.
Data center water usage closely parallels energy usage and carbon emissions. As data centers use more energy for their typical data center operations and to meet AI requests, they consume larger amounts of water to cool their processor chips, so as to avoid overheating and potential damage. Similarly, as energy use increases in data centers, so do carbon emissions.
A medium-sized data center can consume up to roughly 110 million gallons of water per year for cooling purposes, equivalent to the annual water usage of approximately 1,000 households. Larger data centers can each “drink” up to 5 million gallons per day, or about 1.8 billion annually, usage equivalent to a town of 10,000 to 50,000 people. Together, the nation’s 5,426 data centers consume billions of gallons of water annually. One report estimated that U.S. data centers consume 449 million gallons of water per day and 163.7 billion gallons annually (as of 2021). A 2016 report found that fewer than one-third of data center operators track water consumption. Water consumption is expected to continue increasing as data centers grow in number, size, and complexity.
According to scientists at the University of California, Riverside, each 100-word AI prompt is estimated to use roughly one bottle of water (or 519 milliliters). This may not sound like much, but billions of AI users worldwide enter prompts into systems like ChatGPT every minute. Large language models require many energy-intensive calculations, necessitating liquid cooling systems.
The expansion of artificial intelligence brings a challenge that goes beyond electricity: how to remove heat from servers without intensifying the competition for water. Researchers at the University of Texas at Austin have investigated an alternative to meet this growing demand. Instead of relying solely on freshwater sources, data centers could—following appropriate treatment—utilize brackish water, seawater, or water produced during oil extraction.
The study, published in the journal *Water Research*, evaluated desalination systems designed to produce low-salinity water for use in data centers. The work combines technical and economic analyses, exploring various treatment configurations.
The concept does not involve circulating contaminated water directly through the equipment; rather, the water must first be processed to achieve a quality suitable for its intended use.
According to the university’s announcement of the research, the necessary technologies already exist. Vaibhav Bahadur, one of the lead researchers, states that part of the problem can be addressed with currently available solutions, though their implementation comes at a cost.
Different technologies are suited to different conditions. The researchers examined reverse osmosis, mechanical vapor compression, and systems that combine both processes. In reverse osmosis, membranes separate salts from water under pressure. In vapor compression, the treatment involves evaporation followed by condensation.
The choice depends on the characteristics of the water source. The study considered brackish water, seawater, and water produced during oil extraction, which can have an even higher salinity.
The study also analyzed methods for managing brine—the concentrated liquid left over from the treatment process. Recovering more water reduces the volume of waste, but it requires additional energy and investment. Therefore, efficiency must be evaluated by considering both the amount of water obtained and the resources consumed to produce it. Higher salinity water may come at a higher cost... In one of the modeled scenarios, a hybrid system applied to seawater recovered 736 liters of fresh water for every 1,000 kilograms of water processed. The estimated cost was US$ 3.20 per cubic meter produced.
For oil-field produced water with higher salinity, another system showed a similar recovery rate, but at a cost of US$ 10.40 per cubic meter. Energy consumption was also higher. These figures correspond to the specific conditions analyzed in the study and do not represent universal price points.
Despite this additional expense, the researchers state that even the most intensive treatment options account for only a small fraction of a data center’s total energy consumption. Feasibility, therefore, depends on the combination of the available source, the chosen technology, and local conditions.
The oil and gas industry generates large volumes of wastewater. The possibility of treating this water for cooling purposes addresses two needs simultaneously: managing an industrial waste product and supplying facilities that require heat dissipation.
This connection could reduce the strain on water sources used by local communities. However, transforming waste into a resource requires careful evaluation of the treatment process and the final disposal of the resulting brine; one cannot assume that every source will be equally advantageous.
The study also proposes an indicator to estimate how the use of saline water affects the pressure on local water resources. The goal is to facilitate the comparison of different alternatives, taking into account the specific location where a data center operates.
Environmental analysis must also account for the water used to generate electricity. A study on data centers from the University of Texas highlights the distinction between direct water demand—within the facility itself—and indirect demand, associated with energy supply.
In that separate report, researchers estimated that the sector could account for between 3% and 9% of total water use in Texas by 2040, depending on factors such as growth, cooling methods, and the electricity generation mix. Although the context is regional, the issue is of interest to other countries that are hosting new facilities. Planning data centers requires balancing water availability, energy capacity, and treatment infrastructure. Desalination expands the range of options, but its benefits must be demonstrated for each individual project.
AI data centers rely on massive amounts of freshwater (primarily "blue water") and electricity for cooling and power generation. A single hyperscale facility can consume between 1 million and 5 million gallons of water per day—an amount comparable to the daily usage of a town with 10,000 to 50,000 residents.
Industry solutions and technologies are emerging to reduce or replace this heavy reliance on traditional water sources:
Alternative cooling technologies:
• Direct-to-Chip Liquid Cooling: Uses sealed pipes to circulate specialized coolants (such as water-glycol mixtures) directly over microprocessors, moving heat away without open evaporation.
• Immersion Cooling: Submerges entire server arrays into non-conductive, specialized dielectric fluids that boil on contact with hot components to absorb and transfer thermal energy in a closed loop.
• Closed-Loop Systems: Used by companies like Nvidia (via DSX systems), Microsoft, AWS, and Meta, which recirculate coolant and nearly eliminate direct makeup water needs, though they can shift some of the demand over to higher electricity usage.
• Hybrid Rear-Door Heat Exchangers: Capture and reject heat closer to the source to lower reliance on room-wide air or water conditioning.
Alternative power and water sources:
• Fuel Cells: Hydrogen and fuel-flexible fuel cells (such as systems from Bloom Energy) operate with significantly less water than conventional thermal power generation and can capture byproduct heat and water for local use.
• Strategic Siting and Water-Positive Operations: Moving data centers to regions with sustainable water supplies or implementing strict wastewater recycling and public reporting frameworks can cut future direct water footprints by up to 86%.
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