Bridging knowledge between unsaturated geomechanics and energy geotechnics

The crucial interaction between lessons learned from the study of unsaturated soil mechanics and energy geotechnics was highlighted at the recent third edition of the International Symposium on Energy Geotechnics (SEG23), held in Delft, the Netherlands. This short communication summarises the discussion that revolved around handling the many issues raised by the current energy transition from fossil fuels to more sustainable and renewable resources, and the need to integrate unsaturated soil knowledge into energy geotechnics. The panel discussion at the symposium emphasised how crucial it is to use the fundamental concepts of unsaturated soil mechanics for a range of energy applications to be able to characterise key underlying multi-phase processes and enable efficient design. With representatives from around the world, the panel discussion’s goal was to close the gap between theoretical research and real-world applications by fostering a dialogue between academics and industry, thereby advancing creative and sustainable geotechnical solutions. The understandings generated from this conversation highlighted the necessity of ongoing cooperation and knowledge sharing to propel area developments and successfully address the urgent energy and environmental challenges of our time. • An international and diverse panel addressed the role of unsaturated soil mechanics in energy geotechnics. • Application examples include radioactive waste disposal, geothermal systems, and unconventional oil and gas recovery. • The broad relevance of unsaturated soils beyond traditional applications like dams and embankments were stressed. • The application of knowledge in thermo-hydro-mechanical behaviour is critical in energy geotechnics. • Collaboration between industry and academia is crucial amid the needs for an energy transition.