1. Trapping the Earth’s Internal Heat
GEOTHERMAL ENERGY
Trapping the Earth’s Internal Heat

2. How is Geothermal Energy Generated?
Temperatures hotter than the sun’s surface are continuously produced inside the earth by a slow decay of radioactive particles
The most common method that scientists use to find geothermal reservoirs is drilling a deep well and testing the temperature deep underground.
Steam or very hot water from deep within the earth is piped to the surface and used as a heat source or to produce electricity.
Earth’s kinetic energy is converted into electricity.

3. Energy Efficient and Cost Effective
According to the EPA, geothermal are the most energy efficient, cost effective, and environmentally clean systems for temperature control

4. Uses and Goals
Heat pumps – heat and cool building; melt snow from roads and sidewalks
Direct use applications – greenhouses, heat water for fish farming, pasteurize milk, food dehydration, gold mining
Power plants – produce electricity
Help mitigate global warming

5. How is Geothermal Energy Generated?
Temperatures hotter than the sun’s surface are continuously produced inside the earth by a slow decay of radioactive particles
People around the world use geothermal energy to produce electricity and heat their homes by digging deep wells and pumping the heated water or steam to the surface

6. Where is Geothermal Energy Found?
Found along major plate boundaries where earthquakes and volcanoes are concentrated
Geysers
Hot springs
Fumaroles
Geothermal reservoirs

7. The Ring of Fire

8. The US and Geothermal Energy
Most of the geothermal reservoirs in the U.S. are located in the western states, Alaska and Hawaii.
California generates the most electricity from geothermal energy.
"The Geysers" dry steam reservoir in northern California is the largest known dry steam field in the world and has been producing electricity since 1960.
7 states have geothermal power plants
In 2008 U.S. geothermal power plants produced 0.4% of total electricity in the United States.

9. Geothermal Energy is the U.S.

10. Iceland
Iceland plans to run its entire economy on renewable hydropower, geothermal energy, and wind; and use these sources to produce hydrogen gas for running all of its motor vehicles and ships by the year 2050.

11. Geothermal Power Plants
Require high temperatures (300 F – 700 F) hydrothermal resources that may either come from dry steam wells or hot water wells
There are three types of geothermal power plants: dry steam plants, flash steam plants, and binary cycle power plants

12. Dry Steam Plants
Use steam piped directly from a geothermal reservoir to turn the turbogenerator

13. Flash Steam Plants
Takes high pressure hot water from deep inside the earth and converts it to steam to drive the generator turbines
When the steam cools it condenses into water and is injected into the earth to be used over and over again.
Most geothermal plants are flash steam plants

14. Flash Steam Power Plants are the most common form of geothermal power plant. The hot water is pumped under great pressure to the surface. When it reaches the surface the pressure is reduced and as a result some of the water changes to steam. This produces a ‘blast’ of steam. The cooled water is returned to the reservoir to be heated by geothermal rocks again.

15. Binary Cycle Power Plants
Transfers the heat from geothermal hot water to another liquid.
The heat causes the second liquid to turn to steam which is used to drive a generator turbine.

16. Geothermal Power Plant Piping

17. Geothermal Power Plants and the Environment
Geothermal power plants do not burn fuel to generate electricity so their emission levels are very low
Release less that 1% of carbon dioxide emissions of a fossil fuel plant
Use scrubber systems to clean the air of hydrogen sulfide
Emits 97% less acid rain-causing sulfur compounds than fossil fuel plants

18. Advantages Very high efficiency/high net yield
Very reliable (runs 24 hrs. a day)
Very clean – no air pollution or GHGs
Renewable and sustainable
Conserves fossil fuels
Can help decrease dependence of foreign oil
No transportation involved

19. Disadvantages Can’t provide our current energy needs
Can only be used in certain geologically active areas
Water contains minerals that can be corrosive and difficult to dispose of safely
Harmful gases can escape from deep within the earth
Piping system requires large areas of land
Initial costs can be high