FAQ

At 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 long-term use of geothermal heat. A focus lies on the physics of induced seismicity. Researchers conduct different experiments. Whereas some put a strong emphasis on the geothermal processes involved, others test different drilling and stimulation techniques. A dense monitoring system allows to observe even the smallest changes in stress, pressure, and fluid movements. Only in a rock laboratory, such close monitoring is possible and affordable.

Many insights into the creation of geothermal reservoirs were gained from the Bedretto Reservoir Project. This project was a kind of initial project for the BedrettoLab. It encompassed three sub-projects with complementary targets for the development of a large-scale deep reservoir for the circulation of water and the storage and extraction of geothermal energy. One of these projects was VALTER, in which a proxy of a geothermal reservoir was created.

We hope to gain a better understanding of the relevant processes in the framework of a deep geothermal exploration. Our results aim at contributing to a safer and more sustainable use of geothermal energy in Switzerland and elsewhere. This is a precondition for being able to increase the share of geothermal energy by five to ten percent, needed to fulfil the goals set in the Energy Strategy 2050.

The “Bedretto Underground Laboratory for Geosciences and Geoenergies” itself will not generate any heat or electricity for commercial use, but one experiment will create a geothermal reservoir, which will be used to test heat exchange on a monthly and yearly basis.

The BEACH project further explores the potential for heat storage in cristalline rock.

Related to geothermal research is the earthquake physics research. In the framework of the FEAR project, we conduct research to better understand fundamental processes leading to an earthquake and putting it to a halt.

Please have a look at the following page: Activities.

The owner Matterhorn-Gotthard-Bahn has currently given ETH Zurich the permission to use the tunnel as a research infrastructure for eight years.

Experiments & Safety

Very small, not perceptible earthquakes are an inherent part of deep geothermal projects. They cause fractures and keep them open, both enhancing the permeability of a reservoir necessary for an efficient operation. The aim of every geothermal project is to enhance the permeability without causing any felt or damaging earthquakes. In some cases, they also cause felt or damaging earthquakes even though the aim of every geothermal project is to enhance the permeability without causing such events.

At the “Bedretto Underground Laboratory for Geosciences and Geoenergies”, very small earthquakes are as well expected. Compared to natural, damaging earthquakes, the size of the volume stimulated and the depth of the rock volume are considerably smaller. Therefore, the risk of provoking perceptible or even damaging earthquakes is extremely low. A dense monitoring system allows us to observe even smallest seismic activity.

Before an experiment is carried out, the potential risk is evaluated in advance and the experiment is designed to mitigate potential risks. During the experiment, a so-called traffic light system, which evaluates real-time data, supports the extent to which an experiment must be adjusted immediately or stopped if a previously defined magnitude threshold is exceeded.

Our aim is to investigate how we can prevent noticeable or damaging earthquakes and not how we can cause them in the BedrettoLab.

Environment

There are no environmental risks since we do not inject any chemicals, nor will any other harmful substances be used.

Work safety

A rock laboratory including the handling of different instruments, heavy equipment and tools naturally offers a less safe working environment than a regular office. Therefore, different measures are taken to protect the technicians and researchers working at BedrettoLab. In addition to mandatory protective clothing, work processes are defined in advance and monitored as far as possible.

Occupational safety is inspected at regular intervals by an external body, as is the condition of the tunnel in terms of changes to the walls and ceilings and potential risk of rock fall.

The Bedretto tunnel, connecting the Ticino with the Furka tunnel, offers ideal conditions to perform these experiments. It allows to pursue the research conducted in laboratories at universities and in other rock laboratories, e.g. at Grimsel, on a bigger scale.

Similar experiments have already been conducted on smaller scales at university laboratories or at the Grimsel rock laboratory. The ”Bedretto Underground Laboratory for Geosciences and Geoenergies” now offers the opportunity for experiments on a bigger scale, which allows verifying previous results in a more realistic setting. Instead of stimulating rock formations at a couple of centimetres as in a laboratory, or at a scale of 10 meters as in Grimsel, experiments will be conducted on a scale of 100 meters and more. Therewith, the rock formation stimulated is still smaller than in a real deep commercial geothermal project, but significantly bigger than what has scientifically been analysed so far. In addition, the coverage of 1,000 to 1,500 meters above the tunnel simulates well the pressure conditions at relevant depths for a geothermal reservoir.

Deep geothermal energy accesses rock structures at least 400 meters into the earth, and various uses are possible depending on the temperatures in the subsoil.

Temperatures of between 20 °C and 70 °C are found in aquifers (layers of rock or soil that can absorb and hold water) at depths of 400 to 2,000 meters. The thermal water found at these depths is suitable not only for bathing but also for heat production, and systems that exploit the drainage water from tunnels can be put to a similar use (SFOE, Nutzung der Erdwärme - Überblick, Technologie, Visionen).

At depths of 4,000 meters, temperatures beneath Switzerland are between 150 °C and 200 °C. Geothermal energy projects that access these layers of rock generally use part of the energy recovered directly for power production, while the rest can be fed into a district heating grid.

A distinction is made between two systems for energy recovery at great depth: petrothermal and hydrothermal. For further information visit: www.seismo.ethz.ch/en/knowledge/things-to-know/geothermal-energy-earthquakes/forms-of-geothermal-energy/.

We facilitate visits for the following groups upon request and according to our capacities:

• Media
• Research groups
• Industry related to geothermal / engineering / geosciences
• Interest groups in the field of geothermal energy, renewable energies, geosciences

Please contact Stefanie Zeller (stefanie.zeller@sed.ethz.ch) for further information.

There are no more public tours scheduled for the rest of this year (2024). Public tours will be held again in 2025, led by guides from the Museum Sasso San Gottardo.
Dates will be announced in spring 2025 on our website. Tickets will be available for purchase through Museum Sasso San Gottardo.

More infos about the tours can be found here: https://www.bedrettolab.ethz.ch/en/about/visit/

See Contact for more information.