New generation of small geothermal power stations for the Swiss energy grid: Basler & Hofmann joins the Innosuisse project “AEGIS”

26. Oktober 2022

Basler & Hofmann has joined Innosuisse’s flagship project “AEGIS-CH”. For four years a consortium made up of representatives from research and industry has been pushing ahead with the development of so-called “Advanced Geothermal Systems”. These systems promise to make Switzerland's energy supply network more independent and more resilient. The basis for these advancements is new drilling technology using high-voltage pulses.

Whenever the topic of geothermal energy is raised, attention usually turns swiftly to high drilling costs and man-made earthquakes. Thanks to the new Innosuisse project “AEGIS”, this could very soon be a thing of the past.

Advanced Geothermal Systems: small geothermal power stations

As part of the project, which is under the leadership of ETH Zurich, a comprehensive analysis of the Swiss energy system was conducted taking into account a new generation of small geothermal power stations. Together with the Paul Scherrer Institute, the Eastern Switzerland University, and the industry partners Basler & Hofmann, SwissGeoPower, Kibag, Geotherm, Amber Group and Sika Services, the project is looking at ways to develop and refine so-called “Advanced Geothermal Systems”, or AGS for short. Basler & Hofmann is contributing its expertise in the energy sector to the project, as well as driving the further development and marketing of AGS technology via SwissGeoPower. In a very simplified way of looking at the system, AGS can be considered as a huge geothermal probe, where holes drilled down to depths of 2 to 10 km are connected by means of multiple cross-connections. Together, these form a closed loop in which CO2 circulates as a heat transport medium. A single AGS can deliver an electric power output of approx. 1MW or a thermal power output of approx. 10 MW.

Drilling with high-voltage pulses

AGS is made possible by the development of new drilling technology, so-called “Plasma Pulse Geo Drilling”. This uses high-voltage pulses to fracture rock at great depths through the formation of a plasma. The new drilling method solves two problems associated with previous fracking technology. Firstly, it is much cheaper, as the huge outlay for switching out the drilling heads deep underground is no longer necessary. Secondly, the technology poses no threat in terms of tremors or even earthquakes.

The consortium is confident that the new Advanced Geothermal Systems (AGS) can make a significant contribution to reducing energy imports and offsetting fluctuations in the generation of solar and wind energy.

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