272-5 Mapping Geologic Thermal Energy Storage Potential Across the United States

Abstract:

Storing thermal energy underground for later use in electricity production or direct-use heating/cooling is a promising green energy option. Reservoir thermal energy storage (RTES) is one such approach that stores energy in underutilized permeable strata with low ambient groundwater flow rates and more geochemically evolved waters (e.g. brackish/saline) relative to overlying aquifers. The U.S. Geological Survey is assessing the national potential of RTES by focusing on five generalized geologic regions in the United States: Basin & Range, Coastal Plain, Illinois Basin, Michigan Basin, and Pacific Northwest. Reservoir models are developed for the following eight metropolitan areas to evaluate RTES performance across different climates and subsurface environments: Albuquerque, New Mexico; Charleston, South Carolina; Chicago and Decatur, Illinois; Lansing, Michigan; Memphis, Tennessee; Phoenix, Arizona; and Portland, Oregon. Evaluated metrics include required well spacing, thermal storage capacity, and thermal recovery efficiency through time. Potential complicating factors considered for each reservoir include reservoir depth, free convection, and groundwater salinity. This work focuses on direct-use cooling because the need for cooling representative modern office buildings (25,000 square-feet, two stories) greatly exceeds that for heating in most parts of the country; however, the evaluated metrics are also relevant to heating and electricity applications. Results indicate that favorable RTES conditions exist in every region, with the Coastal Plain and Basin & Range being particularly favorable for thermal storage capacity, while the Pacific Northwest and Michigan Basin excel at energy recovery for the evaluated cooling application. The results underscore the utility of developing maps of thermal storage capacity, subsurface temperature models, and volumetric estimates of thermal storage capacity to serve as potential key RTES resource classification standards. Overall, this pre-assessment provides an initial understanding of RTES potential in several cities and geologic regions throughout the country and could aid further evaluation of national RTES efficacy.

Geological Society of America Abstracts with Programs. Vol. 58, No. 5, 2026

doi: 10.1130/abs/2026AM-19498

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.