Turning segmental tunnels into sources of renewable energy

Geothermal energy is a universal low-grade renewable energy source and can be built into any engineering structures that provide large interface areas with the ground. There are already a number of case studies on retrieving geothermal energy from tunnels lined with sprayed concrete, but this paper presents a new system for segmental tunnel linings. Following a field trial in Germany it has been successfully installed in a new high-speed railway tunnel in Austria to supply a municipal building with heating energy. The paper demonstrates how subsurface urban structures can contribute both to sustainable city planning and the provision of decentralised renewable energy.