GeothermalEnergy.pptVIP

Geothermal Energy Sources of Earth’s Internal Energy Different Geothermal Energy Sources Direct uses of geothermal energy is appropriate for sources below 1500C How Direct Uses Work Ground Heat Collectors Generation of Electricity is appropriate for sources 150oC Geothermal’s Harmful Effects Geothermal’s Positive Attributes Useful minerals, such as zinc and silica, can be extracted from underground water. Geothermal energy is “homegrown.” This will create jobs, a better global trading position and less reliance on oil producing countries. US geothermal companies have signed $6 billion worth of contracts to build plants in foreign countries in the past couple of years. In large plants the cost is 4-8 cents per kilowatt hour. This cost is almost competitive with conventional energy sources. Availability of Geothermal Energy On average, the Earth emits 1/16 W/m2. However, this number can be much higher in areas such as regions near volcanoes, hot springs and fumaroles. As a rough rule, 1 km3 of hot rock cooled by 1000C will yield 30 MW of electricity over thirty years. It is estimated that the world could produce 600,000 EJ over 5 million years. There is believed to be enough heat radiating from the center of the Earth to fulfill human energy demands for the remainder of the biosphere’s lifetime. World Wide Geothermal Uses and Potential * * 70% comes from the decay of radioactive nuclei with long half lives that are embedded within the Earth Some energy is from residual heat left over from Earths formation. The rest of the energy comes from meteorite impacts. Hot Water Reservoirs: As the name implies these are reservoirs of hot underground water. There is a large amount of them in the US, but they are more suited for space heating than for electricity production. Natural Stem Reservoirs: In this case a hole dug into the ground can cause steam to come to the surface. This type of resource is rare in the US. Geopressured Reservoirs: In this