Energy and climate policy is facing major challenges not only in Switzerland but worldwide. In addition to the production of electricity and heat from renewable energy, energy storage is another key factor for a successful energy transition. The development of new storage technologies is essential to minimise the use of primary energy and thus also CO₂ emissions.

Underground thermal storage systems are highly efficient. The heat recovery factor is exceptionally high. They can be used not only for short-term storage but also as an ideal long-term storage solution. Furthermore, they take up almost no space on the earth's surface. The consumption of resources for construction and operation is very low, with attractive costs at the same time. As a rule, groundwater is not used as a storage medium for large amounts of energy due to restrictive water protection legislation in Switzerland. Artificially created deep geothermal energy storage (EGS storage) can play an important role here. The innovative concept of Geo-Energie Suisse envisages a modified form of the multi-stage stimulation system with horizontally oriented cracks or layers that are penetrated by vertical boreholes. Such geo-storage facilities could theoretically be realised at almost any location.