Addressing Data Center Cooling Needs Through the Use of Reservoir Thermal Energy Storage Systems: Journal of Clean Energy and Energy Storage

This study investigates using reservoir thermal energy storage (RTES) to reduce the significant energy use and minimize water consumption for data center cooling. Techno-economic analysis was performed for a representative 70 MW hyperscale data center and a 30 MW crypto-mining data center at two representative locations. The investigation shows that both systems are technically feasible and thermally sustainable for at least a period of 20 years without major modifications to the systems. The calculated levelized cost of cooling for using RTES to cool the 70 MW and 30 MW data centers is 11.9 and 14.8 ($/MWh), respectively, and the average cooling provided by RTES is 60% and 36%, respectively. The significance of the RTES cooling is to store cheap cooling in winter and use it in the summer, when cooling is in much more demand. Additional benefits of RTES include enhanced resiliency during high heat events, improved computational efficiency through lower operating temperatures, and significant water conservation by reducing the need for cooling towers. Two key factors contribute to an economically feasible and attractive RTES location: The first is a shallow, non-potable water-bearing geological formation with high transmissivity to maximize storage capacity and minimize the drilling cost. The second key factor is the potential to use free or inexpensive cooling for both direct data center cooling and RTES cooling. Future studies should consider using chillers for RTES cooling when there is a significant electric grid value to do so (large difference between peak and off-peak power cost), as well as system optimization.