A new study from the National Renewable Energy Laboratory demonstrates that underground thermal energy storage (UTES) can provide year-round cooling for computing facilities, potentially eliminating the chillers and cooling towers that currently consume up to 40 percent of a data center’s total electricity demand and millions of gallons of water annually. By storing winter’s cold underground and retrieving it during summer peaks, the approach shifts cooling loads off the grid when power is most constrained and expensive.
The findings arrive as hyperscale operators and colocation providers face mounting pressure to decouple growth from resource intensity. Conventional evaporative cooling remains dominant because it is cheap to install, but it ties facility operations to local watershed stress and exposes operators to rising water rates and regulatory risk. UTES sidesteps both issues by using the subsurface as a seasonal battery, circulating fluid through borehole arrays that can be sited beneath parking lots or greenfields without competing for surface real estate.
Economic modeling in the study suggests levelized cost of cooling reductions of 15 to 30 percent compared with air-cooled chillers in climate zones with distinct heating and cooling seasons. The advantage narrows in persistently hot regions where the ground cannot fully regenerate its thermal capacity, but even there, hybrid designs that pair UTES with dry coolers can shave peak demand charges. For utilities, widespread adoption would flatten the notorious summer afternoon ramp driven by data center clusters, reducing the need for peaker plants and transmission upgrades.
Deployment barriers remain, including higher upfront capital, geological uncertainty, and a design community more familiar with mechanical plants than subsurface engineering. The laboratory’s next phase will field-validate performance at a pilot site in the Midwest, instrumenting a 1-megawatt IT load served by a 200-borehole array. If results match simulations, the technology could move from niche sustainability showcase to standard specification for new builds within the next procurement cycle.
Read the full report at CleanTechnica