| Title | Optimal Energy Production and Density for Open-Loop Shallow Geothermal Systems |
|---|---|
| Authors | Carl Jacquemyn, Matthew Jackson |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Aquifer Thermal Energy Storage (ATES) and open-loop unidirectional Groundwater Heating and Cooling (GWHC) systems can supply sustainable, low carbon heating and cooling. Energy production, energy density (energy supplied per unit surface area) and coefficient of performance (COP) are all important design parameters. Here we explore how these design parameters are impacted by operational decisions such as well spacing, screen length and screen depth over a range of common aquifer properties. We establish a framework to simulate the impact of a wide range subsurface and design parameters to deduce their impact on ATES and GWHC system performance. Aquifer thickness, lateral permeability and permeability anisotropy are considered as variable aquifer properties, and well lateral spacing and vertical offsetting of well screens as key design decisions. The thickness of the injection and production interval can be dictated by aquifer permeability variations and/or the chosen screen length. Results indicate that ATES systems always produce more energy than equivalent GWHC systems. They also offer higher energy density, which may be important in urban settings with high demand per unit area. The optimal combination of high energy and high energy density is obtained from ATES systems with long screen length and close borehole spacing that is slightly less than twice the thermal radius. GWHC systems, or ATES systems with large borehole spacing that offer high thermal recovery, may not be the optimum strategy to deliver heating and cooling in densely populated urban areas, or at sites with high demand but small available land area. |