RTES System Reduces Data Center Cooling Energy Consumption

A new study highlights reservoir thermal energy storage (RTES) as a cost-effective method for cooling data centers. Researchers at the National Laboratory of the Rockies (NLR) published findings in *Applied Energy* demonstrating RTES's potential to lower energy consumption amid rising global electricity demands from AI and cloud computing. The study, released December 6, 2025, details how RTES systems store cold energy underground for later use during peak demand periods. RTES operates by chilling water and injecting it into subsurface reservoirs during cooler periods, leveraging inexpensive electricity and cold ambient air. When cooling is needed, the stored cold water is pumped up and used in heat exchangers to cool data centers. NLR's analysis indicates that RTES achieves nearly seven times the efficiency of conventional cooling methods. The study reports cost reductions from $15 per megawatt-hour (MWh) with traditional systems to $5/MWh using RTES. The research suggests that geothermal systems offer significant potential for economical cooling solutions. Ongoing investigations focus on optimizing energy use within RTES at low pressure to further decrease data center cooling expenses. The findings offer a pathway to reduce the carbon footprint of data centers, which are significant energy consumers.