In the frame of DESTRESS Work Package 5, the Bedretto demonstration site in Switzerland is the fall-back option that replaces Haute-Sorne, Switzerland. It aims to show that the multi-stage stimulation concept is feasible in granitic rocks. The underground laboratory is located in granitic rocks at an approximated depth of 1.1 km below surface in the middle of a 5.2 km long tunnel connecting the Bedretto Valley of the Canton of Ticino with the Furka tunnel. Its location was chosen because enough crystalline rock volume can be accessed to create a reservoir of a similar characteristics to deep underground environment, except for the temperature that remains there constant at 17 °C.
Between 14 January and 7 February 2020, a DESTRESS-led stimulation treatment was performed in the Bedretto Underground Laboratory. It aimed to assess the feasibility of stimulating fractures in a short borehole section of 10 m to permanently increase their transmissivity. The results will be used for the planification of the main stimulation treatment planned for Summer 2020, which will demonstrate a multi-stage stimulation concept to increase energy production and to minimize induced seismicity. In combination with the installed seismic monitoring system, a Traffic Light System (TLS) will be set up as a binding action schema. For its prediction capabilities, an Adaptive Traffic Light System (ATLS) will also be set up and used for decision support.