Geothermal heat from the Turin metro south extension tunnels

Underground geotechnical structures (piles, diaphragm walls, tunnel linings, anchors, etc.) can be instrumented to become energy geo-structures. This paper focuses on the use of energy tunnels, which are shown to have a number of advantages. An example of a possible application to the Turin Metro line 1 South Extension is discussed. Preliminary results of numerical analyses, performed to study the hydro-thermal interaction and the influence of the energy tunnel on the surroundings, will be described. These show that the energy stored in the ground can be exploited without generating relevant effects on the aquifer, highlighting the importance to improve the understanding of the geothermal process and to explore the potential of energy tunnels, allowing for great economic and environmental benefit.