Numerical investigation of closed-loop geothermal systems in deep geothermal reservoirs

Journal Article · 03 November 2023 · Geothermics

DOI: https://doi.org/10.1016/j.geothermics.2023.102852 · OSTI ID:2205271

White, Mark  ^[1]; Vasyliv, Yaroslav Vladimirovich ^[2]; Beckers, Koenraad  ^[3]; Martinez, Mario J. ^[2]; Balestra, Paolo ^[4]; Parisi, Carlo  ^[4]; Augustine, Chad ^[3]; Bran-Anleu, Gabriela A. ^[2]; Horne, Roland N.  ^[5]; Pauley, Laura ^[6]; Bettin, Giorgia ^[2]; Marshall, Theron ^[4]; Bernat, Anastasia  ^[1]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
2. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
3. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
4. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
5. Stanford University, CA (United States)
6. Pennsylvania State University, University Park, PA (United States)

Closed-loop geothermal systems (CLGSs) rely on circulation of a heat transfer fluid in a closed-loop design without penetrating the reservoir to extract subsurface heat and bring it to the surface. We developed and applied numerical models to study u-shaped and coaxial CLGSs in hot-dry-rock over a more comprehensive parameter space than has been studied before, including water and supercritical CO₂ (sCO₂) as working fluids. An economic analysis of each realization was performed to evaluate the levelized cost of heat (LCOH) for direct heating application and levelized cost of electricity (LCOE) for electrical power generation. The results of the parameter study, composed of 2.5 million simulations, combined with a plant and economic model comprise the backbone of a publicly accessible web application that can be used to query, analyze, and plot outlet states, thermal and mechanical power output, and LCOH/LCOE, thereby facilitating feasibility studies led by potential developers, geothermal scientists, or the general public (https://gdr.openei.org/submissions/1473). Our results indicate competitive LCOH can be achieved; however, competitive LCOE cannot be achieved without significant reductions in drilling costs. We also present a site-based case study for multi-lateral systems and discuss how our comprehensive single-lateral analyses can be applied to approximate multi-lateral CLGSs. Looking beyond hot-dry-rock, we detail CLGS studies in permeable wet rock, albeit for a more limited parameter space, indicating that reservoir permeability of greater than 250 mD is necessary to significantly improve CLGS power production, and that reservoir temperatures greater than 200°C, achieved by going to greater depths (~3–4 km), may significantly enhance power production.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States); Idaho National Laboratory (INL), Idaho Falls, ID (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Office; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Technology Development (EE-20)
• Grant/Contract Number: AC36-08GO28308; AC05-76RL01830; NA0003525; AC07-05ID14517
• OSTI ID: 2205271
• Alternate ID(s): OSTI ID: 2229353; OSTI ID: 2290363; OSTI ID: 2311437; OSTI ID: 2328509
• Report Number(s): NREL/JA-5700-86072; INL/JOU-24-76460-Rev000; SAND-2023-13267J; PNNL-SA-192135; MainId:86845; UUID:31e5292a-115e-4bba-b6f4-44fb6debf352; MainAdminID:71214
• Journal Information: Geothermics, Vol. 116; ISSN 0375-6505
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English