1. Slide 1 of 122, © 2000 Geothermal Education Office

2. Geothermal energy is the natural heat of the Earth. Slide 2 of 122, © 2000 Geothermal Education Office

3. Heat flows outward from Earth's interior. The crust insulates us from Earth's interior heat. The mantle is semi-molten, the outer core is liquid and the inner core is solid. Slide 3 of 122, © 2000 Geothermal Education Office

4. The deeper you go, the hotter it gets (in Fahrenheit and miles). Slide 4 of 122, © 2000 Geothermal Education Office

5. The deeper you go, the hotter it gets (in Celsius and kilometers). Slide 5 of 122, © 2000 Geothermal Education Office

6. Earth's crust is broken into huge plates that move apart or push together at about the rate our fingernails grow. Convection of semi-molten rock in the upper mantle helps drive plate tectonics. Slide 6 of 122, © 2000 Geothermal Education Office

7. New crust forms along mid-ocean spreading centers and continental rift zones. When plates meet, one can slide beneath another. Plumes of magma rise from the edges of sinking plates. Slide 7 of 122, © 2000 Geothermal Education Office

8. Thinned or fractured crust allows magma to rise to the surface as lava. Most magma doesn't reach the surface but heats large regions of underground rock. Slide 8 of 122, © 2000 Geothermal Education Office

9. Rainwater can seep down faults and fractured rocks for miles. After being heated, it can return to the surface as steam or hot water. Slide 9 of 122, © 2000 Geothermal Education Office

10. This steaming ground is in the Philippines. Slide 10 of 122, © 2000 Geothermal Education Office

11. When hot water and steam reach the surface, they can form fumaroles, hot springs, mud pots and other interesting phenomena. Slide 11 of 122, © 2000 Geothermal Education Office

12. When the rising hot water and steam is trapped in permeable and porous rocks under a layer of impermeable rock, it can form a geothermal reservoir. Slide 12 of 122, © 2000 Geothermal Education Office

13. A geothermal reservoir is a powerful source of energy! Slide 13 of 122, © 2000 Geothermal Education Office

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15. Many areas have accessible geothermal resources, especially countries along the circum-Pacific "Ring of Fire," spreading centers, continental rift zones and other hot spots. Slide 15 of 122, © 2000 Geothermal Education Office

16. These and other methods are used. Slide 16 of 122, © 2000 Geothermal Education Office

17. Exploration commonly begins with analysis of satellite images and aerial photographs. Slide 17 of 122, © 2000 Geothermal Education Office

18. Volcanoes are obvious indications of underground heat, this volcano, Mt. Mayon in the Albay province of the Philippines erupted in 1999. Slide 18 of 122, © 2000 Geothermal Education Office

19. Geologists explore volcanic regions to find the most likely areas for further study, like this steaming hillside in El Hoyo, Nicaragua. Slide 19 of 122, © 2000 Geothermal Education Office

20. Geologic landforms and fault structures are mapped in the region. This view overlooks Basin and Range terrain East of the Sierra Nevadas. Slide 20 of 122, © 2000 Geothermal Education Office

21. Rocks are examined up close. Slide 21 of 122, © 2000 Geothermal Education Office

22. Geologic maps like this one are created, showing rock type and ages in different colors. Slide 22 of 122, © 2000 Geothermal Education Office

23. Data from electrical, magnetic, chemical and seismic surveys is gathered in the field. Slide 23 of 122, © 2000 Geothermal Education Office

24. The data obtained in the field are displayed in various ways and analyzed. Slide 24 of 122, © 2000 Geothermal Education Office

25. Geologists and drillers study the data to decide whether to recommend drilling. Geothermal reservoirs suitable for commercial use can only be discovered by drilling. Slide 25 of 122, © 2000 Geothermal Education Office

26. First, a small- diameter "temperature gradient hole" is drilled (some only 200' deep, some over 4000 feet deep) with a truck-mounted rig to determine the temperatures and underground rock types. Slide 26 of 122, © 2000 Geothermal Education Office

27. Workers on a temperature gradient hole drilling project. Slide 27 of 122, © 2000 Geothermal Education Office

28. Either rock fragments or long cores of rock are brought up from deep down the hole and temperatures are measured at depth. Slide 28 of 122, © 2000 Geothermal Education Office

29. Geologists examine the cored rock (shown here marked with depth markers). Slide 29 of 122, © 2000 Geothermal Education Office

30. Temperature results like this would definitely encourage the drilling of a larger, deeper well to try to find a hydrothermal reservoir. Slide 30 of 122, © 2000 Geothermal Education Office

31. Production-sized wells require large drill rigs like these and can cost as much as a million dollars or more to drill. Geothermal wells can be drilled over two miles deep. Slide 31 of 122, © 2000 Geothermal Education Office

32. On these large rigs, drilling continues 24 hours per day. Slide 32 of 122, © 2000 Geothermal Education Office

33. If a reservoir is discovered, characteristics of the well and the reservoir are tested by flowing the well. Slide 33 of 122, © 2000 Geothermal Education Office

34. If the well is good enough, a wellhead, with valves and control equipment, is built onto the top of the well casing. Slide 34 of 122, © 2000 Geothermal Education Office

35. This photograph shows a vertical geothermal well test in the Nevada Desert. Slide 35 of 122, © 2000 Geothermal Education Office

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37. Natural steam from the production wells power the turbine generator. The steam is condensed by evaporation in the cooling tower and pumped down an injection well to sustain production. Slide 37 of 122, © 2000 Geothermal Education Office

38. Like all steam turbine generators, the force of steam is used to spin the trubine blades which spin the generator, prducing electricity. But with geothermal energy, no fuels are burned. Slide 38 of 122, © 2000 Geothermal Education Office

39. Turbine blades inside a geothermal turbine generator. Slide 39 of 122, © 2000 Geothermal Education Office

40. Turbine generator outdoors at an Imperial Valley geothermal power plant in California. Slide 40 of 122, © 2000 Geothermal Education Office

41. Turbine generator in a geothermal power plant in Cerro Prieto, Mexico. Slide 41 of 122, © 2000 Geothermal Education Office

42. Geothermal power plant operators in geothermal power plant control room in the Philippines. Slide 42 of 122, © 2000 Geothermal Education Office

43. Substation with transformer and insulators, at a geothermal power plant. Slide 43 of 122, © 2000 Geothermal Education Office

44. Wood power poles delivering electricity from geothermal power plants in the Mojave Desert in California to the electrical grid. Steam from well-testing in background. Slide 44 of 122, © 2000 Geothermal Education Office

45. Those white plumes you see at geothermal power plants are steam (water vapor). Geothermal plants do not burn fuel or produce smoke. Slide 45 of 122, © 2000 Geothermal Education Office

46. Geothermal power plants are clean and are operating successfully in sensitive environments. Slide 46 of 122, © 2000 Geothermal Education Office

47. These geothermal plants are operating successfully in a Philippine cornfield, at Mammoth Lakes, Calif., in the Mojave Desert of California, and in a tropical forest, at Mt. Apo, Philippines. Slide 47 of 122, © 2000 Geothermal Education Office

48. There are different kinds of geothermal reservoirs and different kinds of power plants. Slide 48 of 122, © 2000 Geothermal Education Office

49. In dry steam power plants, the steam (and no water) shoots up the wells and is passed through a rock catcher (not shown) and then directly into the turbine. Dry steam fields are rare. Slide 49 of 122, © 2000 Geothermal Education Office

50. Prince Piero Ginori Conti invented the first geothermal power plant in 1904, at the Larderello dry steam field in Italy. Slide 50 of 122, © 2000 Geothermal Education Office

51. The first modern geothermal power plants were also built in Lardello, Italy. They were destroyed in World War II and rebuilt. Today after 90 years, the Lardello field is still producing. Slide 51 of 122, © 2000 Geothermal Education Office

52. The first geothermal power plants in the U.S. were built in 1962 at The Geysers dry steam field, in northern California. It is still the largest producing geothermal field in the world. Slide 52 of 122, © 2000 Geothermal Education Office

53. 20 plants are still operating at The Geysers. Wastewater from nearby cities is injected into the field, providing environmentally safe disposal and increased steam to power plants. Slide 53 of 122, © 2000 Geothermal Education Office

54. Flash steam power plants use hot water reservoirs. In flash plants, as hot water is released from the pressure of the deep reservoir in a flash tank, some if it flashes to steam. Slide 54 of 122, © 2000 Geothermal Education Office

55. Flash technology was invented in New Zealand. Flash steam plants are the most common, since most reservoirs are hot water reservoirs. This flash steam plant is in East Mesa, California. Slide 55 of 122, © 2000 Geothermal Education Office

56. This flash plant is in Japan. In flash plants, both the unused geothermal water and condensed steam are injected back into the periphery of the reservoir to sustain the life of the reservoir. Slide 56 of 122, © 2000 Geothermal Education Office

57. This plant operates in the middle of crops in the Imperial Valley, California. High mineral contents of some southern California geothermal reservoirs provide salable byproducts like silica and zinc. Slide 57 of 122, © 2000 Geothermal Education Office

58. This flash plant is in Dixie Valley, Nevada. Nevada is rich in geothermal resources, with more hot springs for its size than any other state. Slide 58 of 122, © 2000 Geothermal Education Office

59. In a binary cycle power plant (binary means two), the heat from geothermal water is used to vaporize a "working fluid" in separate adjacent pipes. The vapor, like steam, powers the turbine generator. Slide 59 of 122, © 2000 Geothermal Education Office

60. In the heat exchanger, heat is transferred from the geothermal water to a second liquid. The geothermal water is never exposed to the air and is injected back into the periphery of the reservoir. Slide 60 of 122, © 2000 Geothermal Education Office

61. Binary technology allows the use of lower temperature reservoirs, thus increasing the number of reservoirs that can be used. This binary plant is at Soda Lake, Nevada. Slide 61 of 122, © 2000 Geothermal Education Office

62. This power plant provides about 25% of the electricity used on the Big Island of Hawaii. It is a hybrid binary and flash plant. Slide 62 of 122, © 2000 Geothermal Education Office

63. This binary power plant, at Wendell-Amadee, California, runs by itself. If it detects a problem, it automatically radios the operator to come to the site. Slide 63 of 122, © 2000 Geothermal Education Office

64. This small binary power plant is in Fang, Thailand. Slide 64 of 122, © 2000 Geothermal Education Office

65. Geothermal power has many local and global benefits. Slide 65 of 122, © 2000 Geothermal Education Office

66. The fastest growth in US geothermal capacity was from 1980 to 1990, following enactment of federal laws that compelled utilities to purchase electricity from independent power producers. Slide 66 of 122, © 2000 Geothermal Education Office

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69. People who live in these areas are receiving electricity from geothermal power plants. Slide 69 of 122, © 2000 Geothermal Education Office

70. Geothermal power could serve 100% of the electrical needs of 39 countries (over 620,000,000 people) in Africa, Central/ South America and the Pacific. See:http://www.geotherm.org/PotentialReport.htm Slide 70 of 122, © 2000 Geothermal Education Office

71. Producing electricity is a relatively new use of geothermal energy. People have used Earth's natural hot water directly since the dawn of humankind. Slide 71 of 122, © 2000 Geothermal Education Office

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74. This historical drawing depicts Native Americans using hot springs at what is now Calistoga, California. Some tribes considered hot springs to be neutral territory where no wars were allowed. Slide 74 of 122, © 2000 Geothermal Education Office

75. Use of hot springs by Maoris of New Zealand for cooking and other purposes extends into modern times. Slide 75 of 122, © 2000 Geothermal Education Office

76. Modern day Beppu Japan uses geothermal water and heat in buildings and factories and has 4,000 hot springs and bathing facilities that attract 12 million tourists a year. Slide 76 of 122, © 2000 Geothermal Education Office

77. Bathing in hot pools like these at Hot Creek, Mammoth Lakes, California, has been practiced throughout history. Be careful -- people and animals have been burned badly in unfamiliar pools. Slide 77 of 122, © 2000 Geothermal Education Office

78. Since Roman times, we have piped the hot water into pools to better control the temperature. These are photos of outdoor and indoor pool and spa bathing in Japan, the US, and Europe. Slide 78 of 122, © 2000 Geothermal Education Office

79. This small greenhouse is heated with geothermal water. Plants grow faster and larger when they have additional heat available. Slide 79 of 122, © 2000 Geothermal Education Office

80. In several western US states, many long greenhouses are built and heated with geothermal water. This one is in New Mexico. Slide 80 of 122, © 2000 Geothermal Education Office

81. Peppers, tomatoes, and flowers are commonly grown in geothermally heated greenhouses. Slide 81 of 122, © 2000 Geothermal Education Office

82. Geothermal water is also used to speed the growth of fish. These are growing in a geothermally heated hatchery at Mammoth Lakes, California. Slide 82 of 122, © 2000 Geothermal Education Office

83. This net full of fish was grown in geothermally heated waters in California's Imperial Valley. Slide 83 of 122, © 2000 Geothermal Education Office

84. Closeup of individual fish from a geothermal fish farm. Slide 84 of 122, © 2000 Geothermal Education Office

85. Closeup of a prawn grown in a research project with geothermally heated water at the GeoHeat Center, Oregon Institute of Technology. Slide 85 of 122, © 2000 Geothermal Education Office

86. These alligators are grown in geothermally heated water in Idaho. Slide 86 of 122, © 2000 Geothermal Education Office

87. Geothermal water is also used for industrial uses, like drying lumber or food products. This plant in Brady, Nevada, provides dried onions to Burger King. Slide 87 of 122, © 2000 Geothermal Education Office

88. Pipes of geothermal water can be installed under sidewalks and roads to keep them from icing over in winter, like this sidewalk in Klamath Falls, Oregon. Slide 88 of 122, © 2000 Geothermal Education Office

89. In some places, geothermal water is piped from wells to heat single homes or whole residential or commercial districts. This truck-mounted drill rig is drilling a well for use in Klamath Falls, Oregon. Slide 89 of 122, © 2000 Geothermal Education Office

90. Hot water from one or more geothermal wells is piped through a heat exchanger plant to heat city water in separate pipes. Hot city water is piped to heat exchangers in buildings to warm the air. Slide 90 of 122, © 2000 Geothermal Education Office

91. The geothermal water never mixes with the city water. Once its heat is transferred to the city water, the geothermal water is injected back into the reservoir to be reheated and recycled. Slide 91 of 122, © 2000 Geothermal Education Office

92. This is a "plate type" heat exchanger which passes hot geothermal water past many layers of metal plates, transferring the heat to other water passing through the other side of each plate. Slide 92 of 122, © 2000 Geothermal Education Office

93. These pumps are used to pump the heated water to buildings in a district heating system, after it has passed through the heat exchanger. Slide 93 of 122, © 2000 Geothermal Education Office

94. This photo of Reykjavik, Iceland, was taken in 1932, when buildings were all heated by burning of (imported) fossil fuels. Slide 94 of 122, © 2000 Geothermal Education Office

95. Today, about 95% of the buildings in Reykjavik are heated with geothermal water. Reykjavik is now one of the cleanest cities in the world. Slide 95 of 122, © 2000 Geothermal Education Office

96. The first geothermal district heating system in the US was built in Boise, Idaho. Today, Boise's capital and city buildings are heated with a geothermal district heating system. Slide 96 of 122, © 2000 Geothermal Education Office

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99. The areas in orange and red are where with today's technology, we can find and use geothermal reservoirs. Slide 99 of 122, © 2000 Geothermal Education Office

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101. Geothermal heat pumps can be used almost everywhere in the world, without a geothermal reservoir. The insulating properties of the earth, just below our feet, can keep us warm or cool. Slide 101 of 122, © 2000 Geothermal Education Office

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104. Different styles of pipes are installed beside a building. A liquid is piped through the pipes to pick up the heat FROM the ground or (in the summer) to bring heat from the building TO the ground. Slide 104 of 122, © 2000 Geothermal Education Office

105. In a poll, over 95% of people who had installed a geothermal heat pump said they would recommend it and would do it again. Slide 105 of 122, © 2000 Geothermal Education Office

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108. The entire U.S. (and most other areas of the world) are suitable for geothermal heat pumps. In the U.S., geothermal reservoirs occur primarily in western states. Slide 108 of 122, © 2000 Geothermal Education Office

109. It is of critical importance that we use energy sources that are easy on the environment. Slide 109 of 122, © 2000 Geothermal Education Office

110. Our modern world relies more and more on electricity -- to run our simplest household appliances, to keep businesses humming, to operate our computers and to light the night. Slide 110 of 122, © 2000 Geothermal Education Office

111. We rely on abundant, affordable energy. We must conserve, use energy more efficiently, and diversify our energy resource base. Slide 111 of 122, © 2000 Geothermal Education Office

112. Today, coal provides 55% of the U.S. electricity supply and the U.S. imports more than half of the oil it consumes. The burning of fossil fuels cannot be sustained. Slide 112 of 122, © 2000 Geothermal Education Office

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114. Much air pollution is caused by burning of fossil fuels. The costs of pollution include health effects like rising rates of asthma, especially in children and especially in cities. Slide 114 of 122, © 2000 Geothermal Education Office

115. Currently we are using primarily fossil fuels. Slide 115 of 122, © 2000 Geothermal Education Office

116. What will be the consequences if our growing energy needs are also met by fossil fuels? Slide 116 of 122, © 2000 Geothermal Education Office

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121. You can choose clean renewable energy from wind, solar, small hydropower and geothermal resources. Slide 121 of 122, © 2000 Geothermal Education Office