| Abstract |
Emerging Hot Dry Rock (HDR) technologies such as Geopressured Geothermal Systems (GGS), Enhanced Geothermal Systems (EGS), and Advanced (closed-loop) Geothermal systems (AGS) offer promising pathways for electricity production, particularly in areas without significant subsurface aquifers. GGS is a variant of HDR geothermal systems, which involves injecting water into a well, creating a fracture system and operating wells in a “huff-and-puff†manner in low-permeability, low-porosity rock. For HDR power generation, two key requirements are: (1) access to rock formations exceeding 150°C and (2) engineering fracture systems that can work as downhole heat exchangers. This study presents updated resource estimates for HDR power generation potential in the contiguous United States, focusing on depths of 3, 4, 5, and 6 km. The estimates are based on recent data for subsurface temperatures up to 180°C and consider heat conduction, convection, and depletion physical models to assess the energy extractable over a 30-year plant lifespan. The analysis excludes areas unavailable for industrial development (e.g., national and state parks, conservation zones, and mountainous regions). Our findings indicate a geothermal generation potential of over 5 TW for resources shallower than 5 km and 13 TW for resources less than 6 km. We also provide Levelized Cost of Electricity (LCOE) estimates at each depth in the explored interval. Our analysis shows that LCOE increases with depth, with surface equipment costs becoming the dominant driving force of capital expenditures (CAPEX) over drilling costs. Beyond 6 km, HDR projects encounter challenges with current technologies, highlighting a need for innovation in drilling, completion, and surface technology to unlock the potential of deeper HDR geothermal resources. |