Experiences, Insights and Outlook

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Securing future energy supplies remains one of the greatest political challenges of the coming decades. Due to limited fossil resources, the peak of oil production will probably be passed in the following years, causing rising energy prices, increased competition for natural resources as well as new political and military conflict. Conventional methods of mainly fossil energy production also have serious implications for the stability of the climate. Nuclear energy does not represent a sustainable solution either, since our supply in uranium is just as limited. The only remaining option is to use local energy resources by focusing on environmentally friendly and renewable energies.


Based on a similar line of argumentation, in 2008, the German Bundestag decided to increase the share of renewable energies in the national energy production to 30% by 2020. Already in 2007, 14,2% of the national gross energy consumption came from alternative sources. To meet this goal, geothermal energy is considered a “serious option,” as observed in the 2003 report of the Office for Technological Assessment (Büro für Technikfolgenabschätzung, TAB) at the German Bundestag (report No. 84, February 2003). The total technical potential for energy production is 600 times higher than Germany’s annual energy demand, while the largest part (95%) falls upon deep drilling geothermal plants in Crystalline areas, that is, on EGS technology. Nevertheless, the surveying and use of natural resources remains a little projectable technology, as it is based on tediously collected experiences, a lesson learned by miners and engineers a long time ago. Progress in this area always requires considerable technological and financial effort – an effort that can be best achieved in the context of collective and multinational research projects, involving the state, science and the industry. The European joint project in Soultz will therefore continue to play an important role in the development of EGS-technology.


Since the end of 2007, EGS-technology is tested in two locations in Landau and Soultz, where it is used for the operation of the plant and for commercial energy production. Retrospectively, a number of valuable experiences and insights have been gained since the construction and operation of the plant, particularly with regard to the specificities of the Upper Rhine-Rift.

  • There are no significant developmental deficits in the applied drilling technology. Long-term operation of the plant will have to show if the individual borehole completions meet operational standards. A difficulty presents the (heavily fluctuating) high price of all services that are dependent on the oil and gas industry. Geothermal energy is often times unable to compete with these industries, since profit margins are much smaller than in the hydro carbon industry. The market value of one barrel of hot water is less than one hundredth of one barrel of oil. This situation can only ameliorated by a steadily growing specialized service market that is interwoven with the geothermal industry and tailored to its demands.

  • Experiences with hydraulic simulation technology showed that the possibility for artificially increasing a formation’s permeability is rather limited. In practice, an injectivity rate of more than 1 l/sec/bar is rarely achieved. What follows is that, in order to achieve commercial flow rates with acceptable pressures, reservoir concepts should include formations with already existing natural permeability. Other simulation technologies, such as multiple simulation in one borehole, might open up new possibilities for simulation technology. There are, however, only few practical experiences that can be drawn upon and not all technical questions have been answered. A for us valuable observation was that, in Soultz and Landau, the injectivity measured during simulation did not differ significantly from the remaining injectivity.

Energy is what drives us naturally