PhD Position IDEA League - Using CO2 instead of water as the subsurface energy extraction fluid in EGS and in sedimentary basins

100%, Zurich, temporary

Given the challenges in geothermal operations and the ambitious expansion plans for geothermal energy in many countries, there is an urgent need for experts with a broad understanding of geothermal systems. How can such systems be operated in the most efficient and safe manner? Within the ITN EASYGO, funded by the European Commission, the IDEA League universities TU Delft (TUD), ETH Zurich (ETH), RWTH Aachen University (RWTH), Politecnico di Milano (PoliMi) and 10 industry partners are addressing this question from different perspectives, integrating geology, geophysics, geochemistry, advanced modeling and process engineering. In this framework, EASYGO is looking forward to train tomorrow’s leading geothermal energy experts.

EASYGO is seeking 13 highly qualified and enthusiastic individuals holding a relevant Master degree (or equivalent) to conduct state-of-the-art research within the projects specified below. Please find additional information on EASYGO as well as detailed project descriptions on www.idealeague.org/geothermal-energy and do not hesitate to contact the associated supervisors in case of questions. Successful applicants will conduct their research work at two universities and in close collaboration with industrial partners. They will also benefit from the various training and networking opportunities within the ITN and large-scale infrastructure by the consortium partners across Europe.

Project background

Initial results have shown that using carbon dioxide (CO2) as the subsurface working fluid can considerably improve the efficiency of geothermal energy extraction, while likely reducing fluid-mineral reactions. However, this topic needs to be further investigated, as most publications to date are on theoretical and numerical investigations. What is missing are actual field investigations, where CO2 is injected and circulated through (geothermal) rocks, for example at the Bedretto Underground Laboratory (www.bedrettolab.ethz.ch) in Switzerland and possibly at CO2 Storage sites, such as Aquistore in Canada. We would also like to explore potential cross-fertilizations between CO2-driven EGS systems in crystalline rocks and CO2-Plume Geothermal systems (CPG: geg.ethz.ch/project-co2-plume/) in sedimentary rocks.

Job description

Expected/Potential Project Results

1. Pilot testing of CO2-based geothermal energy extraction, i.e. moving from the purely theoretical/numerical phase to the applied, pilot testing phase of this technology to see if it works under field conditions.


2. CO2 fluid circulation can be maintained over several weeks of subsurface CO2 circulation, i.e. that liquid loading is not causing pumping power requirements that exceed expected power generation rates.


3. Fluid-mineral reactions are such that clogging of CO2 flow paths (particularly in the CO2-EGS case) is not occurring or at least not to the degree of shutting-down the system over anticipated power plant operation times.

Job Description

This project requires considerable field work in the Bedretto Underground laboratory and potentially also at geologic CO2 storage sites, such as Aquistore in Canada, to investigate CO2 circulation and related geothermal energy extraction in Enhanced Geothermal Systems (EGS) and in sedimentary basins, respectively. The work will also require numerical modeling of these large-scale field experiments to help set them up and to analyze their outcomes. During and after the field experiments, data will be acquired and analyzed to help determine if CO2-based geothermal energy extraction in EGS and/or in sedimentary basins is feasible, economical, and can be sustained in principle (i.e. what does it take to reach these goals) and possibly for specific sites worldwide. This latter part will require extensive numerical modeling of subsurface and surface processes as well as CO2 availability and expected levelized cost of electricity of such CO2-based geothermal systems. As a doctoral candidate, you will be enrolled in the ETH Zurich Graduate School and conduct this doctoral work in Prof. Saar’s Geothermal Energy and Geofluids (geg.ethz.ch/) group. This research will be conducted together with the Bedretto Underground Lab team, Geo-Energie Suisse, as well as RWTH Aachen and/or TU Delft. Thus, secondment stays of several months are foreseen at these aforementioned institutions. The project and the associated doctoral degree are expected to be completed within 3 years.

Your profile

We seek a candidate with an MSc degree in (preferably) geoscience/(hydro)geology and with proven excellence in physical and mathematical thinking and with a keen interest, and preferably some experience, in field work and numerical modeling, related to (reactive) subsurface multiphase fluid flow.

Previous knowledge or experience in hydro/geochemistry, geothermal energy, and/or geologic CO2 storage is advantageous. Moreover, the candidate should be a good communicator, have broad interests and learn quickly.

In particular, we are looking for a candidate with the following knowledge and skills:

• Independent, self-motivated, reliable, and eager to learn.


• Ability to work in a project team and take leadership and responsibility for different research tasks.


• An excellent command of English and good academic writing and presentation skills.  

We explicitly encourage female candidates to apply.

Please also note that the European ITN mobility rule applies, which, for this position in Switzerland, means that you cannot have lived in Switzerland for a total of 24 months or more during the past 3 years before the position starts. The position start is anticipated during January-March, 2021.

ETH Zurich

ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000 people from more than 120 countries find our university to be a place that promotes independent thinking and an environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we work together to develop solutions for the global challenges of today and tomorrow. Working, teaching and research at ETH Zurich