1. Geothermal Energy
Prepared by:
Parth H. Patel ( )

2. Geothermal Energy: Introduction
What is geothermal energy?
Geothermal energy- energy that comes from the ground; power extracted from heat stored in the earth
Geo: earth
Thermal: heat

3. Geothermal Energy: History
1960: Pacific Gas and Electric has first successful geothermal electric power plant in US at The Geysers
Turbine lasted more than 30 years

4. Geothermal Energy: History
Used for bathing in Paleolithic times
Ancient Romans used it as central heating system for bathing and heating homes and floors
1892:America’s first district heating system was put into place

5. Power Plant in Larderello Today

6. Geothermal Energy Generation
Direct
Small scale uses
Heating homes
Hot springs
Greenhouse heating
Food dehydration plants
Agriculture
Crop drying
Milk pasteurization
Electrical
Dry steam
Flash steam
Binary cycle

7. How Geothermal Works Earth’s core heat
Water → steam → drive electrical generators
Turbines
Area specific
Geothermal energy is localized

8. Dry Steam Power Plants “Dry” steam extracted from natural reservoir
ºC ( ºF)
4-8 MPa ( psi)
200+ km/hr (100+ mph)
Steam is used to drive a turbo-generator
Steam is condensed and pumped back into the ground
Can achieve 1 kWh per 6.5 kg of steam
A 55 MW plant requires 100 kg/s of steam

10. Single Flash Steam Power Plants
Steam with water extracted from ground
Pressure of mixture drops at surface and more water “flashes” to steam
Steam separated from water
Steam drives a turbine
Turbine drives an electric generator
Generate between 5 and 100 MW
Use 6 to 9 tonnes of steam per hour

12. Binary Cycle Power Plants
Low temps – 100o and 150oC
Use heat to vaporize organic liquid
E.g., iso-butane, iso-pentane
Use vapor to drive turbine
Causes vapor to condense
Recycle continuously
Typically 7 to 12 % efficient
0.1 – 40 MW units common

14. Double Flash Power Plants
Similar to single flash operation
Unflashed liquid flows to low-pressure tank – flashes to steam
Steam drives a second-stage turbine
Also uses exhaust from first turbine
Increases output 20-25% for 5% increase in plant costs

16. Environmental Effects/ Benefits
Remarkable difference of environmental effects compared to fossil fuels
Leaves almost no footprints
Most hardware used to extract geothermal energy is underground
Minimal use of surface
Easy to operate
Open up economy
Much more efficient use of land

17. Environmental Effects/ Disadvantages
Fluids drawn from the deep earth carry a mixture of gases
Pollutants contribute to global warming and acid rain
Construction of Plants can adversely affect land stability
Sources may hold trace amounts of toxic chemicals/mineral deposits
Loud Noises
Initial start up cost (expensive)

18. Conclusion
Overall, geothermal appears to be a sound solution to energy needs
Geothermal energy has the ability to expand
Few environmental effects
Very cost efficient
Geothermal is RENEWABLE

19. (http://www. geothermal. nau. edu/about/enviroment
( shtmlNorthern Arizona University Oct 27)

20. THANK YOU