Recent studies indicate that the economic growth in the developing world combined with a rising population means that global energy demand could double or triple by 2050. (IEA, World Energy Outlook 2007). At the same time, it is known that fossil fuel reserves are finite. And although various scenarios exist and are debated on the future supply of fossil fuels, it is generally acknowledged that there will most likely be a significant gap between energy demand and supply of fossil energy in the future. Thirdly we are experiencing the consequences of a global climate change already, and projections indicate that the average global temperature might continue to rise in the decades to come, which gives an urgent motivation to significantly reduce CO2 emissions.
This is the background on which European scientist initiated the ENGINE project (Enhanced Geothermal Innovative Network for Europe), aiming at coordinating the up to that point scattered European geothermal research, and at expanding the exploitation of Enhanced Geothermal Systems (EGS).
While conventional geothermal resources are economically exploited in various regions of the world already, their occurrence is bound to very specific geologic conditions (spreading centers and subduction zones), or characterized by small temperature differences (shallow hydrothermal systems). Enhanced geothermal systems on the other hand, which are engineered reservoirs, stimulated to produce energy from geothermal resources which lack economical amounts of hot water and/or sufficiently high natural permeability, open up the possibility to tap on the huge geothermal reserves which are existent beyond the regionally limited zones of abnormally high temperatures.
During the course of the last two years, the ENGINE group has explored and compiled the technical state of the art and, where possible, best practices from resource investigation and assessment stage through to exploitation monitoring for various classes of Enhanced Geothermal Systems in typical and representative geological settings. The main question we have to answer is, are we capable of exploiting and operating enhanced geothermal reservoirs in a safely plannable and cost effective manner, and which gaps are still left for us to be filled, in order to achieve this target?
Needs and gaps were identified, and will be presented here with a particular focus on where contributions from geologists can help removing stumbling-blocks, which hamper a more dynamic development and more widespread utilization of deep geothermal energy as a contribution to achieve the ambitious EU objectives for the supply of renewable energy.
The presentation contains contributions from: Abanes R., Asmundson R., Calore, C., Fokker, P., Hopkirk, R.J., Montanari, D., Monterrosa, M., Muller, J., Nami, P., Portier, S., Rummel, F., Sanjuan, B, Schindler, M., Seiersten, M., Stamatakis, E., Tischner, S., Vuataz, F., Zimmermann, G.