The site, near a power plant that could turbinate additional water for the planned geothermal power plant, was ideally located from a hydrogeological point of view and due to the low seismicity. The region is located above a compact bedrock consisting of gneiss and granite layers, which is similar to the crystalline bedrock of Switzerland. The three boreholes drilled by FERVO had provided extensive knowledge of the subsoil in the area concerned. The preparatory work carried out by FERVO had confirmed, among other things, that temperatures of up to 190°C prevail at a depth of 2500 metres. The idea was to pump water into the subsoil, where it would heat up, and then transport it to the surface to use the heat extracted from the rock by turbining the water in an existing power plant.

FERVO chose the method of phased stimulation, which was patented for Switzerland by Geo-Energie Suisse AG in 2012. This method has been successfully tested at a depth of 1,100 metres at the Bedretto underground laboratory and in the FORGE project in the state of Utah, on the border with Nevada. First, a vertical shaft was drilled in Nevada for the measuring instruments, which can be used to monitor the behaviour of the subsoil in real time during and after the work. Then, two further vertical boreholes were drilled to a depth that provides the desired temperature levels, with parallel horizontal extensions. The horizontal extensions then had to be connected, which was achieved by a step-by-step stimulation of the rock. As in Bedretto and Utah, each stimulation step generated imperceptible but measurable seismicity. It is worth noting that the thresholds for increased vigilance and shutdown were higher than in Haute-Sorne in Switzerland. Although proppants were injected at the Blue Mountain site, this is not common practice in geothermal projects in the United States, and no proppants are used at Haute-Sorne. The Blue Mountain power plant has been producing around 3 MWh of geothermal electricity 24 hours a day, seven days a week since November 2023. Google purchases this electricity to power its data centres in Nevada.

Data centres are facilities that consume a lot of electricity 24 hours a day. By decarbonising this consumption, Google aims to make a significant contribution to the fight against climate change. Unlike solar and wind energy, geothermal energy can provide clean base load energy day and night, provided that access to the earth's heat is gained. The construction of the Blue Mountain power plant proved the feasibility of such a project and enabled FERVO to increase the efficiency of drilling techniques by 18% and to reduce costs accordingly, paving the way for the process to be duplicated. FERVO did not need to be asked twice and immediately acquired a concession in the immediate vicinity of the FORGE project in Utah. Between June 2023 and the end of 2023, a vertical shaft and four horizontal wells were drilled at the new site. Stimulation work is currently underway to realise the geothermal well field, with the aim of generating up to 400 MWh of clean electricity.

The American government is providing $220 million in funding for the FORGE project to validate the methods tested and increase their efficiency. The knowledge gained in Utah is already benefiting FERVO through an active exchange of experts. Geo-Energie Suisse AG, which is involved in the FORGE project, is benefiting from this exchange in turn through the new knowledge and work of FERVO. Once the feasibility of Geo-Energie Suisse AG's concept has been proven, the question is whether and under what conditions it can be duplicated in Switzerland. A success in Haute-Sorne would mean that we have reached a decisive turning point in the use of this sustainable technology. GES is benefiting from cost optimisation in the USA. Then nothing would stand in the way of producing carbon-free, sustainable electricity and heat on a larger scale.