At GEOEG, we foster the multiple roles of the underground, a spatial, material and resourceful medium that can support and host structures and infrastructures, as well as provide renewable energy. From this perspective, we developed a multidisciplinary approach allowing to plan, design, and manage it in the most integrated way. Our expertise covers from conventional applications to innovative and complex systems: • Closed geothermal systems (isolated and fields) • Foundation and structural systems • Thermal energy storage systems • District energy systems • Underground thermal characterisation • Energy foundations and infrastructures for both structural support and energy supply (energy piles, walls, slabs, tunnels, etc ...) • Systems involving complex physical conditions (thermal, mechanical, chemical, hydraulic, etc)