The Earth stores an inexhaustible amount of heat for human judgement. On average, the temperature in the subsurface increases by around 3°C for every 100 metres. Accordingly, temperatures of 150°C and more are expected at depths of 5,000 metres. Temperatures of up to around 6,000°C are attributed to the earth's core. This enormous heat reservoir is present everywhere on Earth and can be tapped using various technologies.

People have been using hot water from underground for thousands of years. The use of this naturally occurring hot water is known as hydrothermal geothermal energy.

The ancient Romans' thermal baths, for example, are well known. But buildings were also heated with warm spring water early on. Even electricity has been produced with hot deep water for a good 100 years. In all countries worldwide, there is warm groundwater and deep water that can be used for air conditioning in buildings, agriculture or industrial purposes.

For the production of electricity to be economically viable, the water needs to be at a temperature of at least 150°C and flow at a rate of at least 20-40 litres per second. However, such natural water sources are limited to a few regions worldwide. In Switzerland, too, such occurrences are only found in isolated locations. New innovative methods are therefore needed to extract and use the enormous amounts of energy stored in solid rock.

In order to extract the heat stored deep underground and transport it to the surface, cracks in the solid rock must be enlarged or created so that water can circulate through them. This system of cracks creates a kind of flow heater at depth, through which the heat can be extracted. The aim is to be able to use this innovative system to create a deep geothermal plant for domestic and renewable production of base load energy at any desired location. Geo-Energie Suisse AG is pursuing the breakthrough and establishment of this technology as the Swiss centre of excellence for deep geothermal energy. Thanks to valuable experience gained from projects already completed, the experts at Geo-Energie Suisse AG have optimised the existing process and developed the new, innovative multi-stage stimulation system. Experts refer to the use of geothermal energy by means of such systems as EGS or petrothermal geothermal energy.