ENGINE LAUCHING CONFERENCE ORLEANS Geothermal energy and strategies to reduce greenhouse gas emissions C. Fouillac Research Direction

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 2 « Business as usual »  ΔT > 6°C  ΔT < 2°C Special report «Carbon Dioxide Capture and Storage » IPCC, September 2005 The climate challenge for the 21 st century

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 3 For the next 50 years: the stabilization triangle Pr Robert H. Socolow (Princeton University)

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 4 What is a Wedge? > It is a strategy which allows the reduction of carbon emissions; its effects grow in 50 years from 0 GtC avoided/year to 1 GtC avoided/year. To count in the next fifty years, this strategy must have been demonstrated somewhere today,even at a small scale Total = 25 Gt of Carbon 50 years 1 GtC av. /yr. A « solution » to the CO2 problem should provide a Wedge or a noticeable fraction of a wedge In a cumulative way, a wedge, during its first 50 years of functioning, divert from the atmosphere, a carbon flux of 25 Gt

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 5 Geothermal energy contribution to CO2 emission stabilisation > In 2003,the World running capacity of Geothermal power plants accounted to 8 GWe and produced GWh (Bertani WGC 2005) > Substituting a similar production to coal fired power plants during 50 years would account for 1/25 of a wedge > According to Stefanson (WGC 2005), the to day installed capacity is probably not much than 5% of the actual resource. > Direct uses are difficult to estimate but are very important and rapidly growing. > This preliminary figures do not take the potential impact of EGS into account.

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 6 Geothermal energy: Heat and power generation

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 7 Extrapolated temperatures at 5km depth in Europe < 60° C 60°- 80°C 80°- 120°C 120°- 140°C 140°- 160°C 160° - 180°C 180°- 200°C 200°- 220°C 220°- 240°C > à 240°C

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 8 Pannonian Bassin : T°C at 5000m depth (Genter et al 2004)

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 9 Locating the EGS resource : > 3D predictive modelling of lithology, temperature, permeability and stress distribution > Resource assessment: “Changing the Scale” Europe has produced in the nineties a” European Atlas of geothermal resources” Though very useful, this document has not the appropriate scale to reduce the geological risk to an acceptable level for the promotion of EGS projects European Commission must encourage the member states to refine their geothermal potential assessments. This can produce a digital map (GIS),compatible with other information levels,easy to modify and improve, where detailed knowledge can be added as soon as it will be available.

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 10 Drilling to the HDR / EGS reservoir : costs repartition Operation and maintenance % Power plant % Reservoir stimulation % Drilling % Modified after A. J. Tester (1994)

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 11 Drilling geothermal wells > Difficult and challenging: hot, hard, fractured rocks, corrosive fluids > Compared to oil and gas well drilling, it’s a very small market (~3 Geothermal wells for 1000 Oil and Gas wells) > Foreseen improvement M.W.D. for inclined wells Cutting tools Particle impact drilling > Technological breakthrough Thermal spallation drilling? Laser drilling ?

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 12 Nikola Tesla ’s patent: an ancestor for Hot Dry Rock geothermal exploitation « All that is necessary to open up unlimited resources of power throughout the world is to find some economic and speady way of sinking deep shafts » Nikola Tesla 1931

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 13 Stimulating the reservoir > Develop a heat exchanger large enough to sustain the production during say, 25 years without thermal decline > Keep water losses below acceptable levels 1%,5% ? (depends on water availability and supply cost) > Keep hydraulic impedance below 1l/s/bar this threshold is a site specific function of the energy output and of the pumping energy penalty; it is more or less directly related to the temperature of the reservoir

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 14 Efficient and Optimal use of E.G.S. > Thermal energy extraction from the reservoir Develop new concepts for injection/ production well position and completion Develop innovative approaches of chemical stimulation Develop new concepts of heat extraction “Supercritical CO 2 for down hole circulation fluid and working fluid” > Heat and power production schemes From site to site, it could be more appropriate to deliver power or heat, or both Improve the cost and efficiency of heat- power conversion schemes( heat exchangers, binary cycles, low cost turbines) Develop hybrid schemes (ex: Hybrid EGS- fossil fired power plant, with high energy efficiency and reduced CO 2 emissions)

ENGINE LAUCHING CONFERENCE, 13/02/2006 Research Direction > 15 Conclusions > Geothermal energy can play a very significant role among the CO 2 reduction strategies. > Today, many geothermal direct uses provide very efficient ways for CO 2 reduction but, only hydrothermal reservoirs of high grade resources are used for power production > On the long term (50 years, 100 years) EGS technology has a high potential in continental Europe to increase the contribution of geothermal energy to the reduction of CO 2 emissions > Engine Coordination Action will allow to develop a development of European research efforts and support international cooperation