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News Archive - 2024


Guided tours of the BedrettoLab available to the public from summer 2024

In partnership with the Sasso San Gottardo Museum, ETH Zurich will be offering guided tours of the BedrettoLab to the public from summer 2024. These tours, which will be available on three Saturdays, will be laid on in German and Italian.

Up to now there have only been occasional opportunities for the public to visit this unique research infrastructure. However, that is about to change thanks to a partnership with the nearby Sasso San Gottardo Museum, meaning that members of the public can tour the BedrettoLab on the following dates this year:

  • Saturday 20 July 2024
  • Saturday 3 August 2024
  • Saturday 28 September 2024
  • tours start at each date: 11 a.m., 12 a.m., 2 p.m., 3 p.m.

On each of these days we will be offering four guided tours in German and four in Italian. Those interested in taking part can check the time slots for each language online. Tours can be booked now on the Sasso San Gottardo Museum's website (www.sasso-sangottardo.ch/bedrettolab) at a price of CHF 25 per person.

What does a tour involve?

It will consist of a walking tour lasting around two hours and covering a distance of about 4.5 kilometres. This means that it is only suitable for individuals who will have no trouble navigating their way across uneven terrain for this length of time. Geology and research are brought together in the BedrettoLab: the Sasso San Gottardo Museum's guides will lead visitors through the unclad rock tunnel holding the BedrettoLab, while pointing out and explaining various geological phenomena that would be difficult to spot otherwise. Visitors can also take in the BedrettoLab's geothermal test environment, giving them an insight into the ongoing research work at ETH Zurich.

Direct link for ticket sales: www.sasso-sangottardo.ch/bedrettolab

More information about the guided tours is available here: www.bedrettolab.ethz.ch/en/about/visit

Alle Infos auf Deutsch: www.bedrettolab.ethz.ch/en/about/visit/public-visits-info-DE/



Doctoral thesis exploring geomechanical characterization methods

In his recently published doctoral thesis at the BedrettoLab, Kai Bröker explored geomechanical characterization methods—ranging from mini-frac tests to borehole breakout analysis and hydraulic stimulation experiments—to enhance the understanding of stress measurement in fractured crystalline rock masses. Therewith he shed light on various methods of stress measurements in granitic reservoirs and their implications for hydraulic stimulations. His investigations revealed a complex stress field heterogeneity influenced by natural fractures, fault zones, and tunnel excavation.

Furthermore, his analyses of the hydraulic stimulation experiments suggest hydraulic shearing of pre-existing fractures as a probable reactivation mechanism. The pressure and flow rate datasets and their interpretation will help in the future integration and interpretation of monitoring data for seismicity, strain and pressure as well as in the improvement of numerical models for hydraulic stimulations.

For his doctoral thesis, Kai drew on a wealth of experience that he gained in the BedrettoLab, where he already completed his Master's thesis on “In-situ stress and rock mass characterisation via mini-frac tests at the Bedretto Underground Laboratory”. In addition to his excellent scientific work, Kai has been involved in setting up and developing the BedrettoLab from the very beginning. We, the entire BedrettoLab team congratulate him on his completed doctoral thesis and are happy that he is continuing his work in the BedrettoLab as a postdoctoral researcher at the Center for Hydrogeology and Geothermics at the Université de Neuchâtel.

For more insights, access here the doctoral thesis of Kai with the titel “From stress field heterogeneity to hydraulic stimulation mechanisms: Insights from a hectometer-scale fractured rock mass”.


First long-term injection experiment successfully finished

At the end of April, the BedrettoLab team successfully conducted their first long-term injection experiment. The experiment lasted several days aiming to generate an earthquake of about magnitude 0 and monitor it from close by.
Following a week of preliminary tests and a four-day preparation phase, high-pressure hydraulic stimulation commenced, with around-the-clock real-time monitoring. The target earthquake occurred at 6 o'clock in the morning of 30 April, somewhat earlier than expected, achieving the experiment's goal and prompting the cessation of injection.

In an earthquake of this magnitude, the rock moves along a plane by about 1-2 millimeters over an area of roughly 5-by-5 meters. This rupture lasts only a millisecond and radiates seismic waves, which our sensitive monitoring arrays are designed to capture. The waves are much too weak to be felt at the surface.
The seismology team uses these detailed recordings of such a small event to study the physical processes that occur during an earthquake. A better understanding of such processes may lead to improvements in earthquake risk mitigation and management in the future. It also contributes to better management of induced seismicity related to deep geothermal energy projects. Currently, the team is analyzing and modeling the collected data, and preparing the next long-term injection scheduled for autumn.


BedrettoLab team at SOLA Staffette 2024

Last Saturday 14 team members participated at the SOLA Staffette, a relay race covering a total of 113 km in and around the city of Zurich. The team finished in 545th place out of 997 teams and was the fastest among many teams from the Earth Science Department of ETH Zurich.


First long-term injection experiment starting in mid-April

The BedrettoLab team is embarking on a new phase of experiments. As part of the FEAR project, a sequence of hydraulic stimulation experiments will start in mid-April. Leveraging on insights gained from the VALTER experiments, the team plans continued injections for an extended period of two to four days, allowing the reactivation and extension of the fracture network of the reservoir created in past experiments. Scientifically, the team is focusing mainly on the seismic response of the reservoir and aims to scale up the seismicity to larger events than previously observed.

In past experiments, the largest observed micro-earthquake was about a magnitude -2; in the upcoming M0 experiment, the team strives to reach about a magnitude 0. Such an event is about 100 times larger in amplitude and releases about 1´000 times more energy than a magnitude -2. Such an event would rupture a patch of about two by two meters by about one centimetre, allowing us to study when and where such a micro-earthquake starts, how it ruptures, and when it stops. For comparison, a natural earthquake of magnitude 6 that occurs in Switzerland every 50 to 150 years ruptures a patch of 10 by 10 kilometres by one meter, releasing about 1 billion times more energy.

Magnitude 0 events have already occurred naturally in the vicinity of the tunnel, and such micro-earthquakes remain about 100 to 1’000 times too small to be felt by people in the Bedretto Valley at a distance of several kilometres. The likelihood of induced larger events that could be detected in the Bedretto Valley remains extremely low. However, even micro-earthquakes of magnitude zero to one can be felt if experienced within a few meters or tens of meters of them. To eliminate even the smallest risk to people in the tunnel, these experiments will not only be very closely monitored, but they will also for the first time be fully remote controlled. During the main injection, no people will be allowed in the tunnel. This remote-control capability will be even more important later in the FEAR project when patches of 10 meters are the target size. 

During the main part of the experiment, about twenty dedicated members of the BedrettoLab team will be working in 24/7 shifts over a period of one week. Their primary task will be to monitor the pressure, flow rate, deformation, and seismicity behaviour in real-time. The geobiological and geochemical response of the reservoir will also be closely monitored, for example, to detect pre-cursors before larger ruptures. As implemented for previous experiments, two traffic light systems regulate the experiment, and if the observed vibrations or magnitude exceed pre-defined thresholds, the experiment will be ended immediately and bleed-off initiated; past experiments have shown that seismicity will then within minutes to hours decrease strongly.


New project to test thermal energy storage in fractured rocks

A new project entitled ‘BEACH: Bedretto Energy Storage and Circulation of Geothermal Energy’ just started with a first meeting of the consortium. It is a pilot and demonstration project funded by the Swiss Federal Office of Energy (SFOE) dedicated to testing, developing, and introducing new technologies from research to the Swiss industrial market.

The project consortium consists of scientists from the BedrettoLab, the Geothermal Energy and Geofluids group at ETH Zurich, researchers from SUPSI, and industry experts from Azienda Elettrica Ticinese (AET) as well as Geo-Energie Suisse (GES).

BEACH will play a key role in tackling the challenges of the Swiss energy transition by demonstrating a new technology for storing and retrieving energy in the subsurface. With the energy grid shifting towards renewable energies such as wind or solar energy, seasonal phases of energy demand surplus demand for an efficient and sustainable solution for energy storage. While thermal energy storage in soft sediments (e.g. in the Netherlands) is well established, storing heat in the hard, fractured rock most common in Switzerland remains largely unexplored.  The BEACH project will explore a so-called fractured thermal energy storage in the limited permeability of the crystalline rocks in the BedrettoLab.

For demonstrating the feasibility, warm water (30 - 70 °C) will be injected into existing fractures, where it will be stored and kept warm by the surrounding rock until it will be retrieved again. In a real-world roll-out scenario, the heat could then be converted into energy or used for district heating.

The tests are accompanied by comprehensive real-time-monitoring and numerical simulations for optimizing the geothermal energy system. Ultimately, the technology will be proposed on a cantonal and national level for real-scale sites to be realized by industrial partners as an additional part of the project. A real-scale reservoir in crystalline rock could be established close to infrastructures with high energy excess and/or demand, such as industrial areas, at depths of around 1 to 3 kilometers.

Maren Brehme from ETH Zurich leads the BEACH project awarded with a fund of 2.96 Mio CHF. The community of Bedretto and the canton of Ticino support the project in rolling out the technology on a national level.


Looking deep into rocks and distant planets: geobiological research in the BedrettoLab

Cara Magnabosco is a professor in geobiology and together with her group she conducts research in the BedrettoLab. Cara is particularly interested in subsurface environments and looks for simple life-forms such as bacteria or other microorganisms that can survive by “breathing rocks”. One of the central questions she is exploring is under which conditions life can emerge and survive. In the BedrettoLab, she and her team have already found some fascinating and rare microorganisms. They are performing a variety of experiments to learn more about their lifestyle.

What is your research in the BedrettoLab about?

My research journey in the BedrettoLab started in 2020. In general, in my field, to get access to “deep ecosystems” is not easy. So, to have the BedrettoLab in such close distance and with almost permanent access is a big opportunity. At the beginning, we just wanted to find out what is there, in the boreholes and in the water that flows through the various fractures. We began to take many water samples to get an idea of the sampled water, where it originates from and what the chemistry looks like. Our aim is to identify energy sources in the water or on the rock surface that can feed microorganisms. Such energy sources include for example CO2 or nitrogen, which can be found in different amounts throughout the tunnel.

Once we got a better idea of what is existing, we also started to examine the effects of hydraulic stimulations on the microbiome, a term for the microogranisms that exist in a particular environment. We observed changes in the water chemistry and microbial populations during stimulations. Now, we maintain a geobiological monitoring borehole and “observe” the water chemistry and biology on a long-term basis with different permanent measuring installations. In this borehole we perform various experiments to better understand how the microorganisms in the BedrettoLab survive and evolve.

We have also installed additional monitoring stations to see if there are seasonal or experimental-associated changes in the system. We called the entire setup “DELOS” which stands for “Deep Life Observatory”, a tribute to the Greek island that shares the same name and prohibited dying. The microorganisms living in Bedretto’s DELOS have refused to die, even though they are hundreds to thousands of meters away from the sun and the surface.

What tools and methods do you use?

My team usually turns up in the tunnel with buckets and lots of bottles. With those vessels, we take our water samples directly from the boreholes or from a water source somewhere in the tunnel. Then we take the samples to our laboratory here at ETH Zurich and analyze them. This means that we look at water drops under the microscope, we do chemical analyzes or, if we identify interesting microorganisms, we try to cultivate them and do DNA sequencing. As we collect lots of data about the DELOS ecosystem as a whole, we also use machine learning to combine these data with the DNA analyses. Machine learning algorithms help us to identify patterns and ultimately connections between the environment or changes in it that lead to changes in the microorganisms, e.g. bacteria, and the occurrences of certain life forms.

Did you discover anything surprising during your research in the BedrettoLab?

We have found a large population of a set of extremely interesting ultra-small bacteria. They have extremely small genomes compared to complex life-forms such as plants and are among the smallest life-forms on earth. So, we are wondering, why exactly those bacteria do occur here, what do they need to survive and where are they originating from.

During the hydraulic stimulations we have also discovered a change in the water chemistry that is quite likely coming from the new fractures created in the rock. This means, when the rock breaks, a reaction is set in motion in which water molecules are split and hydrogen and oxygen is set free. What comes out is a highly reactive liquid that offers energy for potential life. We are wondering, if this was maybe an energy source for early life.

With your “Center for Origin and Prevalence of Life” you also open your eyes to other planets and the possibility of extraterrestrial life. What does your research have to do with life on other planets?

The reaction that I described earlier, where silicate rock, like the Rotondo granite and water react to produce bio-chemical energy, is quite generic. This means that it could also occur in the subsurface of other planets and power alternative ecosystems. This reaction pathway makes the existence of extra-terrestrial life more likely for example on Mars.


ETH’s Robotic Systems Lab in the BedrettoLab

Last Friday, a group from ETH Zurich’s Robotic Systems Lab tested their wheeled-legged robot Chimera in the BedrettoLab. The robot is trained to serve for rescuing, logistics or monitoring in environments that are not accessible for humans. The BedrettoLab and the area in front of the tunnel entry proved to be an ideal environment for testing the robot's locomotion and navigation capabilities in a tough condition.