The heat engine of the Earth represents an infinite and renewable source of energy that could potentially satisfy a significant part of our needs. While conventional geothermal resources already cover a wide range of uses for power and heat production in profitable conditions, the development of engineered geothermal systems still requires significant R&D investment. A large scientific and industrial community has been involved for more than 20 years in promoting Enhanced Geothermal Systems (EGS) and has been recently assembled in ENGINE, a Coordination Action of the 6th Framework Program, aimed at coordinating on-going actions concerning Unconventional Geothermal Resources. The achievement of this project will be a handbook defining best practices and proposing a road map for future demonstration projects. The main results will be presented during the final conference that will be held in Vilnius, Lithuania (12-15 February 2008).
The project, that joins 35 partners (4 of them from Third Countries) and 19 countries, started on 1st November 2005 and up to now, 2 conferences (launching and mid-term) and 7 workshops have been organised. All material elaborated during the project are available through the web site at http://engine.brgm.fr. Proceedings, reports, abstracts and slides can be downloaded, presenting an updated framework of activities concerning (i) investigation, (ii) drilling, stimulation and reservoir assessment, (iii) exploitation, economic, environmental and social impacts.
The enhancement challenge requires the development of innovative methods for exploring, developing and exploiting geothermal resources that are not economically viable by conventional methods. This definition embraces different tracks for enlarging access to heat at depth in order to provide continuous base load-power and to contribute to reach the target of the European Strategic Energy Technology Plan, i.e. 20% renewable market penetration in 2020. Lessons learned from the Soultz EGS experiment, the sustainable development of the Larderello field in Italy, and the Icelandic geothermal power network, among other case histories, highlight the importance for coordinated research for technology improvement and for a continued reduction in cost through R&D developments. Based on the Soultz experience, and thanks to significant progress in binary power plant technology, a new EGS power plant was done in the Upper Rhine graben on the German side and others projects are planned for the coming years, showing a learning curve effect.
There is a sound knowledge shared by the European scientific community to promote geothermal projects and active links with the International Energy Agency and other EGS programs in US, Australia and Japan. In that scope, ENGINE Coordination Action provides that conditions are gathered to promote new EGS demonstration projects through a common approach between R&D teams and stakeholders, providing an added value for European energy resources and industry development. What could be the next move in this direction? Standardization of the elaborated technology and quantification of geologic and technical risks are among the main issues that come out from the contact with the stakeholders and that were debated during the Leiden workshop (Netherlands). Each stage of development of EGS includes several phases and involves pluridisciplinary approaches that can be run in parallel or successively. Decisions are taken at critical moments of the development of the project, marked by go/no go milestones. Review of best practices and lessons learned from the different projects and partners enable the definition of a workflow on which well proven methods and risk assessment can be identified. Concerning each main topic, proven methodologies have been reviewed. Their objectives and main outcomes were presented during the different conferences, workshops and meetings and will be synthesized in the European Reference Manual. Concerning each topic, gaps and barriers must now be identified and evaluated in terms of risk-related and probability of success. R&D themes and investments required to overpass these gaps and barriers could then be defined and constitute a road map for the R&D task force mobilised during the ENGINE co-ordination action for the next years.
In conclusion, it is important on one hand to evaluate the investment and the expected savings on cost operation at the 2020 horizon for each R&D initiative and industrial project. On the other hand, it must be demonstrated that geothermal energy can contribute to achieve the goals defined in the European Strategic Energy Technology Plan. These are our priorities for the next months, until the closure of ENGINE, and for the next years, through EGS demonstration projects. The ENGINE task force is now operational and motivated to develop EGS at the European scale.