Sustainable and carbon-free energy sources are crucial as humanity faces the threat of energy shortages and climate change. The use of geothermal energy dates almost a century back and new developments are underway in the so called “supercritical geothermal systems”, i.e., geothermal systems located in deep volcanic areas. The international authors’ team (a joint effort of TUBAF, UFZ and CSIC) has investigated the potential of supercritical geothermal systems by assessing the safety of their long-term exploitation.
“Research about supercritical geothermal energy is still a rather new field of interest in science and presents extraordinary challenges” says Olaf Kolditz, one of the researchers who participated in the study published in Nature Communications. "It is still difficult to predict exactly how these systems may behave over a longer period of time and how they can be operated safely. The correct assessment of resources and baseline conditions is essential for the design of geothermal systems”. Scientific investigation of superhot geothermal systems is in the focus of the GEMex project “Cooperation in Geothermal energy research Europe-Mexico for development of Enhanced Geothermal Systems and Superhot Geothermal Systems” (http://www.gemex-h2020.eu/index.php?lang=en) led by the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences.
The team of scientists conducted numerical simulations based on the open-source modeling platform OpenGeoSys - developed by the research team - to understand man-made induced seismicity in supercritical geothermal systems. For the first time, researchers have described the complex geomechanical interactions that lead to fault instability and gained important insights into supercritical geothermal systems. The numerical model makes it possible to assess specific geothermal sites, because it can take local geological structures and physical parameters of the rocks into account. The researchers examined how increases in the pore pressure and cooling of the rock mass - a consequence of the re-injection of cold water into the deep reservoir - Future research should address aspects such as the influence of inelastic behaviour and the presence of fluid mixtures on modelling the frictional behaviour during dynamic rupture events.