For several years, France has been pursuing numerous new deep geothermal projects in Alsace, the Paris Basin and the Massif Central.
In 2016, the EGS project in Soultz-sous-Forêts, which started as a research project, entered into commercial operation after more than 20 years. The geothermal plant in nearby Rittershoffen, which was built by Éléctricité de Strasbourg (ÉS) for commercial purposes, was inaugurated in 2016. Extensive stimulation work there has noticeably increased efficiency and profitability.
In the Paris Basin, too, several new heating projects have been realised or are in the process of being implemented in recent years.
In early summer 2017, TLC Geothermics and Storengy applied for two licences to explore geothermal reservoirs in the basement of the Massif Central.
The greater Munich area is a flagship region for the use of geothermal energy. Geothermal energy projects are continuously being implemented in and around the city. By 2040, the entire district heating supply for the city of 1.5 million is to be provided by renewable heat from geothermal energy.
North Rhine-Westphalia (NRW) wants to replace coal-based energy in the next few years. Coal is not only relevant in the electricity sector, but is also an energy source for the largest district heating network in Europe, which is located in the Ruhr area. More than five million people live in this densely populated region. The coal phase-out threatens to create an enormous future supply gap not so much in the electricity supply as in the heating supply. In North Rhine-Westphalia, the geothermal potential is therefore to be explored and later developed and used as part of the TRUDI (Tief runter unter die Ruhr) project, which was launched at the end of 2017. In the first phase, boreholes up to 1,500 metres deep are to be drilled. At this depth, water circulation and the use of the subsurface as a heat store will be tested. ‘Heat storage’ is of great importance for the densely populated Ruhr region. In a later step, the subsoil will then be explored up to 5,000 metres. The project, financed by the state of North Rhine-Westphalia and the German federal government, is being carried out by the Bochum Geothermal Centre (GZB). Geo-Energie Suisse AG regularly exchanges information with the GZB. A joint R&D project was proposed as part of GEOTHERMICA and approved in May 2018.
The Dutch government is seeking to reduce its dependence on natural gas. This is one of the main drivers behind the exponential development of geothermal energy in the country. Numerous projects have been developed to meet the high demand for heat in agriculture, with more in the pipeline. In addition, 2,500 geothermal heat storage tanks were already in operation in the Netherlands in 2015, substantially reducing the country's primary energy consumption and thus also its CO2 emissions.
In 2015, Vito N.V. awarded a contract for five possible geothermal projects in Belgium. The first two wells, with target depths of 3,600 and 4,600 metres respectively, have already been successfully completed and represent the first deep geothermal doublet in Belgium. Drilling work for the third well, which is expected to reach a depth of 5,000 metres, began in October 2017. All projects are designed to supply electricity and heat. Further projects are in the planning stage.
The US Department of Energy has been funding research into EGS projects for decades. The FORGE (Frontier Observatory for Research in Geothermal Energy) project is driving the development of EGS technology in deep wells. The planned budget is around USD 150 million. The aim is not to build a power plant, but solely to further develop the technology to make it industry-ready. In 2017, two projects were awarded the contract for a further stage: Utah (Milford Site) and Nevada (Fallon Site). Both follow the same concept as Geo-Energie Suisse AG.
In Finland, an EGS project is currently being carried out on behalf of the energy supply company st1, in which two wells of up to 7,000 m depth are being drilled in crystalline rock. Geo-Energie Suisse Chairman of the Board Daniel Schafer and CEO Peter Meier visited the drilling site in June 2017. This could be realised on an area of around 3,000 m2. Normally, such 450 t drilling rigs require a drilling site of around 15,000 m2.
In the Finnish project, an innovative air hammer method was successfully tested. Compared to the conventional rotary drilling method, a 10-20 times faster drilling speed could be achieved. Deflected drilling sections were still drilled conventionally. In addition, a fluid hammer method is being developed that should achieve a 10 times faster drilling speed. This method is to be used at drilling depths where the air hammer method can no longer be used.
The drilling in Finland is carried out by the company H. Anger's Söhne, which is also planned for the drilling work of Geo-Energie Suisse AG in Haute-Sorne.
In order to access and use the geothermal heat from the solid rock, a heat exchanger had to be created at depth for the water to flow through. St1 successfully completed the necessary hydraulic stimulation measures at the end of July 2018. As with Geo-Energie Suisse's multi-stage stimulation system, a step-by-step approach was taken.
During the stimulation phase, St1 experts pumped water into the borehole and monitored this process using underground geophones installed in the urban area. In addition, the Institute of Seismology at the University of Helsinki used its own geophones to independently monitor the stimulation. The strongest micro-earthquake reached a magnitude of 1.9. The authorities have set the limits for micro-earthquakes at a much lower level than those used for blasting, for example. Within these limits, the stimulation was carried out in a controlled and safe manner. The limits were set so low because the project is located in the city of Espoo in the greater Helsinki area. The low limits are intended to minimise disruptive effects and to enable a rapid response if necessary. The microseismic activity during the stimulation work could not be felt, but it could be heard as a rumbling and knocking. The noises were recorded and documented on the basis of feedback from local residents and acoustic measurements.