Geothermal energy and tiered synergistic mining of geothermal energy and minerals: Advantages, issues, and paths
Fangchao Kang, Chun’an Tang, Yingchun Li*, Tianjiao Li, Wendi Zhang, Chongchong Cai
Deep Resources Engineering. 2025, 2(3): 100199. 
doi.org10.1016j.deepre.2025.100199.pdf
Abstract: Geothermal resources, especially hot dry rock (HDR), hold the unparalleled potential to decarbonize energy systems and bolster the global clean energy transition. Despite five decades of development, enhanced geothermal systems (EGS) remain constrained by limited power generation capacity, obstructing the commercial viability of deep geothermal energy. A comprehensive understanding of the limitations throughout the system operation is crucial for facilitating large-scale commercial utilization of HDR geothermal energy. Here, we compare the drilling-enhanced geothermal system (D-EGS) and the excavation-enhanced geothermal system (E-EGS) regarding reservoir construction and heat extraction, identifying a critical bottleneck: D-EGS suffers from non-reproducible fractured reservoir construction due to its dependence on site-specific geology, while E-EGS overcomes this by creating universally adaptable caved thermal reservoirs through mining technologies. We further propose a groundbreaking Tiered Synergistic Mining of Geothermal Energy and Minerals (TSMGM) framework, which integrates conventional mining techniques with EGS to extract HDR and mineral resources simultaneously. By stratifying resources into low- (<50 °C), medium- (50–100 °C), and high-temperature (>100 °C) stages, TSMGM facilitates sequential extraction of both geothermal energy and minerals, significantly reducing operational costs and environmental risks. Although the TSMGM confronts substantial scientific and technical barriers, its modular design and tiered temperature-gradient exploitation strategy may advance HDR energy commercialization and enable integrated multi-energy development, positioning TSMGM as a potential catalyst for global carbon neutrality efforts.
Highlights:
• HDR offers decarbonization potential, yet current EGS yields limited power capacity despite five-decade development.
• E-EGS may create replicable caved thermal reservoirs with acceptable fracture networks under different geological conditions.
• TSMGM combines traditional mining and EGS to exploit geothermal energy and minerals, providing a novel HDR mining framework.
• Deep geothermal energy mining via TSMGM needs multidiscipline breakthroughs and cross-scale technological innovations.
Keywords: Geothermal energy; HDR; EGS; E-EGS; Tiered synergistic mining of geothermal energy and minerals
Cite: Kang, F.C.; Tang, C.A.; Li, Y.C.; Li, T.J.; Zhang, W.D.; Cai, C.C., Geothermal energy and tiered synergistic mining of geothermal energy and minerals: advantages, issues, and paths. Deep Resources Engineering 2025, 2 (3): 100199. https://doi.org/10.1016/j.deepre.2025.100199
