GEOTHERMAL ENERGY: A reliable, renewable energy source

1. GEOTHERMAL ENERGY:A reliable, renewable energy source IANAS Workshop: Toward a sustainable energy future

2. GEOTHERMAL ENERGY:A reliable, renewable energy source • Barriers to further development OUTLINE • Origin of geothermal energy • Classification of geothermal resources • Utilization of geothermal resources • Geothermal power generation around the world • Virtues of geothermal technology IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

3. Depth km The heat flows toward the external layers. The crust is a very good thermal insulator. The mantle is partially melted and supports convective heat transport. The external nucleus is postulated to be in a liquid state and the internal nucleus is in a solid state. In addition to the heat flowing to the crust from the inner layers of the Earth, the concentration of radioactive isotopes in the crust and upper mantle, mainly 40K, 232Th, 235U and 238U, generate an estimated 4.7x1020 cal/year. IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

4. Volcanos and island arcs align on the plate boundaries. IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

5. New crust is formed from rising magma in divergent plate boudaries. One plate slides under another in convergent plate boundaries. IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

6. Thermal gradient along the Earth’s radius • As a result of tectonic processes, the thermal gradient in the crust varies enormously from one site to another. • A “normal” thermal gradient is considered to be about 30oC/km(depth). However, in some sites it could be as high as 800 oC/km. IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

7. Geothermal resources classified on the basis of temperatures found at “reasonable” depths: • Low temperature (50 oC – 120 oC) • High temperature (220 oC – 320 oC) • Mid temperature (120 oC – 220 oC) IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

8. Geothermal resources classified on the basis of geological and hidrological factors: • Hidrothermal • Hot, dry rock • Geopressurized • Marine • Magmatic IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

9. A hydrothermal reservoir contains all the elements: hot rock, source of water, permeability. IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

10. Use of Geothermal Energy IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

11. High Temperature Hydrothermal Systems • Electric power generation by direct separation of steam • Electric power generation through organic Rankine cycles, utilizing "spent" fluids • Large-area thermal conditioning of living and commercial quarters • Direct uses of heat in "spent" fluids in industrial or agricultural processes IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

12. Medium temperature hydrothermal sources • Electric power generation through organic Rankine cycles • Large-area thermal conditioning of living and commercial quarters • Direct uses of heat in industrial or agricultural processes IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

13. Geothermal resources classified on the basis of geological and hidrological factors: • Hidrothermal • Hot, dry rock • Geopressurized • Marine • Magmatic IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

14. Incipient: Engineered hot-dry rock resources Electric power generation from heat delivered to the surface by circulating exogenous water through the hot rock IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

15. Power generation with geothermal energy IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

16. Virtues of Geothermal Energy • Reliable and continuous • Flexible; could be used as base generation or load-following mode • Low CO2 emissions • Competitive costs IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

17. AVERAGE PLANT FACTORS PLANT FACTORS References: 1.- Calculated from installed capacities and power generated (Jan-Sep, 2008). Data from CFE webpage. 2.- NEA&IEA (2005) “Projected costs of Generating Electricity: Update 2005” IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

18. Virtues of Geothermal Energy • Reliable and continuous • Flexible; could be used as base generation or load-following mode • Low CO2 emissions • Competitive costs IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

19. IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

20. Virtues of Geothermal Energy • Reliable and continuous • Flexible; could be used as base generation or load-following mode • Low CO2 emissions • Competitive costs IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

21. Levelised Costs LEVELISED GENERATION COSTS References: 1.- NEA&IEA (2005) “Projected costs of Generating Electricity: Update 2005” 2.- CFE (2005) “Costos y parámetros de referencia para la formulación de proyectos de inversión” 3.- Barnett, P. (2007) “Cost of Geothermal Power in New Zealand: 2007 Update”, New Zealand Geothermal Workshop, November 2007 IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

22. Disadvantages of Geothermal Energy • A measure of uncertainty • Capital-intensive initially IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

23. www.iie.org.mx IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008