As artificial intelligence and cloud computing drive an unprecedented surge in electricity demand, a new study published NGWA’s journal Groundwater® points to groundwater as a solution to data center cooling. 
The Issue Paper, “Aquifer Thermal Energy Storage: Groundwater for Efficient Data Center Cooling in the United States,” was authored by Upasana Pandey, Andrew J. Stumpf and Yu-Feng Forrest Lin of the Illinois State Geological Survey and Prairie Research Institute at the University of Illinois Urbana-Champaign.
Data centers already consume enormous amounts of electricity, and depending on design, between 10 percent and 40 percent of that power goes toward cooling alone, much of it through systems that evaporate, and permanently lose, large volumes of water. The study proposes aquifer thermal energy storage, or ATES, as an alternative: groundwater is pumped through subsurface pipes to absorb heat from a data center via a heat exchanger, then returned underground, where it can be stored and reused. Excess summer heat can be banked underground for winter use, and cold groundwater stored in winter can help cool the same facility the following summer.
“The most visible conversation about energy is almost always about quantity, how many megawatts a plant can generate, or how much power a data center will need,” said co-author, Yu-Feng Lin.
“But that’s only one side of the coin. A complete energy strategy also has to account for stability and efficiency, and that’s where groundwater has real advantages most people overlook. Its enormous volume, its remarkably stable temperature, and its ability to carry heat as it flows make it one of the most underused assets we have for managing energy demand.”
The authors point to pronounced seasonal temperature swings, prolific aquifers, and favorable subsurface geology as key factors that make a region well-suited to ATES, with states like Illinois offering a useful model: rather than cooling a facility from a 90-degree summer high or heating it from a subzero winter low, an ATES system lets a facility draw on the earth’s near-constant underground temperature, cutting the swing dramatically and with it the energy needed to manage it.
Importantly, the study notes that these systems don’t require drinking water — deep saline aquifers, some saltier than seawater, along with contaminated groundwater and water-filled abandoned mines, are all viable sources.
The paper concludes that the main barriers to adoption are economic and institutional rather than technical: ATES systems carry higher upfront costs but lower long-term operating costs, and much of the drilling expertise needed already exists within the oil, gas, and water well industries.
The study identifies these properties as central to why groundwater deserves a bigger seat at the table in national energy planning. Nearly every form of power generation other than wind requires water, and the availability of that water routinely determines where power plants are sited.
The ATES systems demonstrate that groundwater could be an active component of energy management by even reducing water usage. As the paper concluded, “This paradigm shift warrants a redefinition of ‘groundwater resources’ to encompass their role in renewable thermal energy storage and thermal regulation, particularly in data center operations and other energy-intensive AI development.”
Click here to read the Issue Paper.
NGWA will host a members-only webinar, Data Centers and Groundwater: What NGWA Members Need to Know, on August 5. Click here to register.
The Association will also host Data Centers, Groundwater, and Sustainable Water Management Forum on December 7 in Las Vegas, Nevada. Click here to register.
Click here to read NGWA’s position paper and other resources on data centers and groundwater.