Geothermal district energy systems coupled with seasonal underground thermal energy storage: A U.S. techno-economic screening by climate and geology

Renewable Energy
By: , and 

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Abstract

In the United States, cooling-dominated commercial building loads can cause geothermal heat pump-based district energy systems to accumulate a long-term subsurface thermal imbalance, motivating the incorporation of seasonal underground thermal energy storage. We developed a transferable workflow to evaluate geothermal district systems that pair ground heat exchangers with seasonal underground thermal energy storage. Using standardized hourly loads for seven commercial buildings and a uniform cost framework, we simulated ten U.S. cities with a physics-based ground heat exchanger model, subsurface storage simulations, and economic assessment to isolate the roles of climate and hydrogeology. In cooling-dominated cities, underground thermal energy storage supplied the majority of annual cooling, cutting electricity use and summer peaks substantially while achieving levelized costs comparable to or below conventional chiller-boiler plants. In cooler climates, the storage share shrunk, required borefield size and costs rose, and levelized cost of energy increased nearly linearly with declining underground thermal energy storage fraction, indicating storage fraction as the primary economic lever. Sensitivity analysis showed capital risk dominated by borefield drilling and surface heating, ventilation, and air-conditioning and piping, with underground thermal energy storage costs secondary. This workflow provides a transparent foundation for site-specific design and screening of next-generation geothermal district energy systems.

Suggested Citation

Mello, S., Oh, H., Trainor-Guitton, W.J., Cahalan, R.C., Pepin, J.D., and Burns, E., 2026, Geothermal district energy systems coupled with seasonal underground thermal energy storage: A U.S. techno-economic screening by climate and geology: Renewable Energy, v. 271, 125540, 15 p., https://doi.org/10.1016/j.renene.2026.125540.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Geothermal district energy systems coupled with seasonal underground thermal energy storage: A U.S. techno-economic screening by climate and geology
Series title Renewable Energy
DOI 10.1016/j.renene.2026.125540
Volume 271
Publication Date May 30, 2026
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) Central Energy Resources Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Description 125540, 15 p.
Country United States
State Arizona, Illinois, Maryland, Michigan, Mississippi, New Mexico, Oregon, South Carolina, Tennessee
City Albuquerque, Annapolis, Charleston, Chicago, Decatur, Jackson, Lansing, Memphis, Phoenix, Portland
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