There was a Youtube video released yesterday by Sabine Hossenfelder, a popular science YouTuber (one with a PhD in theoretical physics—quantum gravity, field theory and 159 published research papers).
Hossenfelder used to think geothermal would only be a ‘niche’ player, and has older videos stating so (drilling costs being the main problem). But she changes her mind in this video, and talks about the big change in forecasts for geothermal production, driven largely by new drilling technologies (cost reductions); the use of AI for production optimization; and the emerging opportunities from EGS techniques, and closed loop systems.
She also references a recent Nature paper that I had missed and that looks really interesting / provides strong support for EGS systems:
Permeability partitioning through the brittle-to-ductile transition and its implications for supercritical geothermal reservoirs
Geothermal projects utilizing supercritical water (≥400 °C) could boost power output tenfold compared to conventional plants. However, these reservoirs commonly occur in crustal areas where rocks are semi-ductile or ductile, impeding large-scale fractures and cracking, and where hydraulic properties are largely unknown. Here, we explore the complex permeability of rocks under supercritical conditions using mechanical data from a gas-based triaxial apparatus, high-resolution synchrotron post-mortem 3D imagery, and finite element modeling. We report a first order control of strain partitioning on permeability. In the brittle regime, strain localizes on permeable faults without necessarily increasing sample apparent permeability. In the semi-ductile regime, distributed strain increases permeability both in deformation bands and the bulk, leading to a more than tenfold permeability increase. This study challenges the belief that the brittle-ductile transition (BDT) marks a cutoff for fluid circulation in the crust, demonstrating that permeability can develop in deforming semi-ductile rocks. https://doi.org/10.1038/s41467-024-52092-0
– Ian Graham, Cascade Institute Visiting Fellow, Energy Systems