1. By Chee lor, Hawa Ireso, Cherja Vang

2. What is it?  Geothermal power plants are built on top of high thermal gradient permeable rocks that allow fluids to flow  The geothermal process uses ground water (hot springs/geysers ) to create electricity with steam

3. How it works  By drilling deep into the earth, we can harness the steam produced by the hot rocks  To achieve this, water is pumped down an injection well (a limited permeable rock basement)  Hydro-fracture occurs when the water is pumped down the well (cracks in the rocks)

4. How it works cont.  A production well is also drilled into the earth  The production well pulls up the hot water which has been heated by the earth’s rocks  Then the hot water is transferred back to the power plant to create steam then transferred back into the injection well  Then that steam is used to power a turbine which then creates electricity

5. How it works cont.  There are 3 different types of geothermal power plants  Dry Steam-produces energy directly from the steam generated underground  Flash Steam-used with a liquid hydrothermal resource with high temperatures  Binary Steam-used with a hydrothermal resource but with a lower temperature

6. Home usage  Heat pumps transfer heat from outside to inside  The refrigerant carries heat from one place to the other  When it’s compressed, it’s a high temp/pressure liquid-if allowed to expand it turns into a low temp/pressure gas-then that gas can absorb heat  The basic principle is that the geothermal heat pumps move heat from the earth into you home and can also pull heat from you house and discharge it into the ground

7. Advantages  Geothermal power plants do not create any pollution  Geothermal power plants are less expensive to build  No fuel is used to generate power  An excellent source of clean, cheap, simple, renewable, power

8. Disadvantages  Only certain locations are suitable for building a geothermal power plant  Land surveys (ground test) are needed to find “hot spots”  “Hot spots” may be located anywhere- even harsh condition lands  Some sites stop producing steam  Dangerous gases can escape when drilling the wells

9. Bibliography  http://www1.eere.energy.gov/geothermal/egs_ animation.html http://www1.eere.energy.gov/geothermal/egs_ animation.html  http://www.pier55.com/technology/energy/geot hermal-energy/ http://www.pier55.com/technology/energy/geot hermal-energy/  http://www.alternativeenergybase.com/Article/ How-Geothermal-Energy-Works-/4 http://www.alternativeenergybase.com/Article/ How-Geothermal-Energy-Works-/4  http://www.renewable-energy- sources.com/2008/06/06/types-of-geothermal- power-plants/ http://www.renewable-energy- sources.com/2008/06/06/types-of-geothermal- power-plants/  http://www.clean-energy- ideas.com/articles/advantages_of_geothermal _energy.html http://www.clean-energy- ideas.com/articles/advantages_of_geothermal _energy.html