Increasing the share of renewable energies is one of the cornerstones of the Swiss Energy Strategy 2050. Geothermal energy is among other renewables a promising resource for electricity and heat production. It makes use of the enormous heat captured deep underground. For this purpose, cold water is injected at high pressure into the rock, where it heats up before it is pumped back to the surface. In Switzerland, the temperature rises by approximately 30 °C for every kilometre below the surface towards the centre of the Earth.
In the “Bedretto Underground Laboratory for Geosciences and Geoenergies”, ETH Zurich studies, in close collaboration with national and international partners, techniques and procedures for a safe, efficient, and sustainable use of geothermal heat. To this end, a sufficiently permeable reservoir is necessary which is accessible on a long-term basis. Researchers conduct different experiments focusing on the different processes in a geothermal reservoir. They use several boreholes in which they have placed a variety of sensors to track even the smallest changes in stress, pressure, and fluid movements. Only in a rock laboratory, such close monitoring is possible and affordable.