New Research Points To Groundwater As Tool For Cooling AI Data Centers

Study published in Groundwater® highlights aquifer thermal energy storage as a feasible, underused solution for the nation's fastest-growing electricity demand

Westerville, OH — As artificial intelligence and cloud computing drive an unprecedented surge in electricity demand, a new study published in the National Groundwater Association'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% and 40% 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 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.”

For more on NGWA's position on this issue, visit NGWA's data centers and groundwater (https://www.ngwa.org/get-involved/advocacy/issue-data-centers-and-groundwater).

The National Ground Water Association is a not-for-profit professional society and trade association for the global groundwater industry. Our members around the world include leading public and private sector groundwater scientists, engineers, water well system professionals, manufacturers, and suppliers of groundwater-related products and services. The Association’s vision is to be the leading groundwater association advocating for responsible development, management, and use of water.