Geothermal energy involves extracting heat from underground and using it to generate electricity or for direct uses like heating and cooling. There are various methods to extract geothermal energy depending on the underground temperature, including dry steam, flash steam, binary cycle, and hot dry rock technology. While geothermal energy has environmental advantages over fossil fuels, development costs are high due to exploration and drilling risks. However, operating costs are low as the fuel source is constant. Geothermal energy provides baseload power and is most economically viable in locations with suitable underground temperatures near the Earth's tectonic plate boundaries.

1. Geothermal Energy Stephen Lawrence Leeds School of Business University of Colorado Boulder, CO 80309-0419

3. Geothermal Overview

4. Geothermal in Context http://www.eia.doe.gov/cneaf/solar.renewables/page/geothermal/geothermal.html U.S. Energy Consumption by Energy Source, 2000-2004 (Quadrillion Btu) 0.143 0.115 0.105 0.070 0.057 Wind Energy 0.063 0.064 0.064 0.065 0.066 Solar Energy 2.845 2.740 2.648 2.640 2.907 Biomass d 0.340 0.339 0.328 0.311 0.317 Geothermal Energy 2.725 2.825 2.689 2.242 2.811 Conventional Hydroelectric 6.117 6.082 5.835 5.328 6.158 Renewable Energy 8.232 7.959 8.143 8.033 7.862 Nuclear Electric Power 0.039 0.022 0.078 0.075 0.115 Electricity Net Imports 40.130 39.047 38.401 38.333 38.404 Petroleum c 23.000 23.069 23.628 22.861 23.916 Natural Gas b 0.138 0.051 0.061 0.029 0.065 Coal Coke Net Imports 22.918 22.713 21.980 21.952 22.580 Coal 86.186 84.889 84.070 83.176 84.965 Fossil Fuels 100.278 98.714 97.952 96.464 98.961 Total a 2004 P 2003 2002 2001 2000 Energy Source

5. Advantages of Geothermal http://www.earthsci.org/mineral/energy/geother/geother.htm

7. Earth Dynamics http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm

8. Earth Temperature Gradient http://www.geothermal.ch/eng/vision.html

9. Geothermal Site Schematic Boyle, Renewable Energy, 2 nd edition, 2004

10. Geysers http://en.wikipedia.org/wiki/Geyser Clepsydra Geyser in Yellowstone

11. Hot Springs Hot springs in Steamboat Springs area. http://www.eia.doe.gov/cneaf/solar.renewables/page/geothermal/geothermal.html

12. Fumaroles Clay Diablo Fumarole (CA) White Island Fumarole New Zealand http://volcano.und.edu/vwdocs/volc_images/img_white_island_fumerole.html http://lvo.wr.usgs.gov/cdf_main.htm

13. Global Geothermal Sites http://www.deutsches-museum.de/ausstell/dauer/umwelt/img/geothe.jpg

14. Tectonic Plate Movements Boyle, Renewable Energy, 2 nd edition, 2004

15. Geothermal Sites in US

16. Extracting Geothermal Energy

17. Methods of Heat Extraction http://www.geothermal.ch/eng/vision.html

20. Dry Steam Schematic Boyle, Renewable Energy, 2 nd edition, 2004

22. Single Flash Steam Schematic Boyle, Renewable Energy, 2 nd edition, 2004

24. Binary Cycle Schematic Boyle, Renewable Energy, 2 nd edition, 2004

25. Binary Plant Power Output http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm

27. Double Flash Schematic Boyle, Renewable Energy, 2 nd edition, 2004

30. Hot Dry Rock Technology Fenton Hill plant http://www.ees4.lanl.gov/hdr/

31. Soultz Hot Fractured Rock Boyle, Renewable Energy, 2 nd edition, 2004

35. Geothermal Heat Pump http://www.worldenergy.org/wec-geis/publications/reports/ser/geo/geo.asp

36. Heat vs. Depth Profile Boyle, Renewable Energy, 2 nd edition, 2004

37. Geothermal District Heating Boyle, Renewable Energy, 2 nd edition, 2004 Southhampton geothermal district heating system technology schematic

38. Direct Heating Example Boyle, Renewable Energy, 2 nd edition, 2004

41. Geothermal Performance Boyle, Renewable Energy, 2 nd edition, 2004

42. Environmental Implications

45. Economics of Geothermal

48. Risk Assessment http://www.worldbank.org/html/fpd/energy/geothermal/assessment.htm

49. Geothermal Development http://www.worldbank.org/html/fpd/energy/geothermal/assessment.htm

50. Cost of Water & Steam http://www.worldbank.org/html/fpd/energy/geothermal/assessment.htm Table Geothermal Steam and Hot Water Supply Cost where drilling is required 10-20 Low Temperature (<100 o C) 20-40 3.0-4.5 Medium Temperature (100-150 o C) 3.5-6.0 High temperature (>150 o C) Cost (US ¢ /tonne of hot water) Cost (US $/ tonne of steam)

51. Cost of Geothermal Power http://www.worldbank.org/html/fpd/energy/geothermal/assessment.htm Normally not suitable 4.0-6.0 2.5-5.0 Large Plants (>30 MW) Normally not suitable 4.5-7 4.0-6.0 Medium Plants (5-30 MW) 6.0-10.5 5.5-8.5 5.0-7.0 Small plants (<5 MW) Unit Cost (US ¢ /kWh) Low Quality Resource Unit Cost (US ¢ /kWh) Medium Quality Resource Unit Cost (US ¢ /kWh) High Quality Resource

52. Direct Capital Costs Direct Capital Costs (US $/kW installed capacity) http://www.worldbank.org/html/fpd/energy/geothermal/assessment.htm Normally not suitable Exploration : US$100-400 Steam field:US$400-700 Power Plant:US$850-1100 Total: US$1350-2200 Exploration:: US$100-200 Steam field:US$300-450 Power Plant:US$750-1100 Total: US$1150-1750 Large Plants (>30 MW) Normally not suitable Exploration: : US$250-600 Steam field:US$400-700 Power Plant:US$950-1200 Total: US$1600-2500 Exploration : US$250-400 Steamfield:US$200-US$500 Power Plant: US$850-1200 Total: US$1300-2100 Med Plants (5-30 MW) Exploration : US$400-1000 Steam field:US$500-900 Power Plant:US$1100-1800 Total:US$2000-3700 Exploration : US$400-1000 Steam field:US$300-600 Power Plant:US$1100-1400 Total: US$1800-3000 Exploration : US$400-800 Steam field:US$100-200 Power Plant:US$1100-1300 Total: US$1600-2300 Small plants (<5 MW) Low Quality Resource Medium Quality Resource High Quality Resource Plant Size

54. Operating/Maintenance Costs Operating and Maintenance Costs http://www.worldbank.org/html/fpd/energy/geothermal/assessment.htm 0.4-0.7 0.6-0.8 0.8-1.4 Total 0.25-0.45 0.35-0.45 0.45-0.7 Power Plant 0.15-0.25 0.25-0.35 0.35-0.7 Steam field O&M Cost (US c/KWh) Large Plants(>30 MW) O&M Cost (US c/KWh) Medium Plants (5-30 MW) O&M Cost (US c/KWh) Small plants (<5 MW)

55. Geothermal Installations Examples

56. Geothermal Power Examples Boyle, Renewable Energy, 2 nd edition, 2004

58. Geothermal Energy Plant Geothermal energy plant in Iceland http://www.wateryear2003.org/en/

59. Geothermal Well Testing http://www.geothermex.com/es_resen.html Geothermal well testing, Zunil, Guatemala

60. Heber Geothermal Power Station http://www.ece.umr.edu/links/power/geotherm1.htm 52kW electrical generating capacity

61. Geysers Geothermal Plant The Geysers is the largest producer of geothermal power in the world. http://www.ece.umr.edu/links/power/geotherm1.htm

62. Geyers Cost Effectiveness Boyle, Renewable Energy, 2 nd edition, 2004

63. Geothermal Summary

65. Next Week: BIOENERGY

66. Supplementary Slides Extras

67. Geothermal Gradient http://www.earthsci.org/mineral/energy/geother/geother.htm

68. Geo/Hydrothermal Systems http://www.freeenergynews.com/Directory/Geothermal/

69. Location of Resources http://www.worldenergy.org/wec-geis/publications/reports/ser/geo/geo.asp

70. Ground Structures Boyle, Renewable Energy, 2 nd edition, 2004

71. Volcanic Geothermal System Boyle, Renewable Energy, 2 nd edition, 2004

72. Temperature Gradients Boyle, Renewable Energy, 2 nd edition, 2004

73. http://www.earthsci.org/mineral/energy/geother/geother.htm

74. UK Geothermal Resources Boyle, Renewable Energy, 2 nd edition, 2004

75. Porosity vs. Hydraulic Conductivity Boyle, Renewable Energy, 2 nd edition, 2004

76. Performance vs. Rock Type Boyle, Renewable Energy, 2 nd edition, 2004

77. Deep Well Characteristics Boyle, Renewable Energy, 2 nd edition, 2004

78. Single Flash Plant Schematic http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm

79. http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm

80. Binary Cycle Power Plant http://www.worldenergy.org/wec-geis/publications/reports/ser/geo/geo.asp

81. Flash Steam Power Plant http://www.worldenergy.org/wec-geis/publications/reports/ser/geo/geo.asp

82. Efficiency of Heat Pumps Boyle, Renewable Energy, 2 nd edition, 2004