Geothermal Energy

What is Geothermal Energy? Humans have been using “geothermal”

energy for hundreds of years

The Earth gives off a lot of heat! Generally, 1km down=25°C hotter

In some places, the proportion is higher

Geothermal energy utilizes this natural heat to: Heat water for use

Make steam to produce energy with

Global Distribution of Geothermal Energy

At least 50 countries have quantifiable amounts of geothermal energy

Top ten countries with the highest Geothermal Energy Output (in MW), and the percentage of their total power output it represents:

1. United States- 3,086 (0.3%) 6. New Zealand- 700 (10%)

2. Phillippines- 1,904 (27%) 7. Iceland- 575 (30%)

3. Indonesia- 1,197 (3.7%) 8. Japan- 536 (0.3%)

4. Mexico- 958 (3%) 9. El Salvador- 204 (14%)

5. Italy- 843 (10%) 10. Kenya- 167 (11.2%)

Geothermal Energy is highly sustainable, if we can utilize it

Geothermal energy is more or less 100% renewable. It’s actually considered an inexhaustible resource. Cooled water is cycled back to be

reheated

The earth has an indefinite amount of heat

Geothermal energy is constant and unaffected by external factors

How Do you make it? To utilize geothermal energy, you need 3 things:

Heat

Fluid

Permeability

*Note that hydrothermal sources, like hot springs have all of these naturally

How Do you make it? There are three kinds of Geothermal

Power Plants: 1. Dry Steam

Uses natural Steam directly

2.Binary Steam

Uses hot water (at 360°F or greater), and uses pressure to turn it into steam

3. Flash Steam

Uses hot water to heat a different liquid

Water/water vapor has no direct contact with the fluid

This is the most common one

The Cost of Geothermal Energy

Plants can produce energy for around 5-8¢ per kWh once cost of purchase has been recovered

However, initial cost is expensive Construction of plant costs about $2500 per

kW

The cost of one well can be anywhere from 1 to 5 million dollars.

Power plants can be only located in rural areas, and over appropriate sources Transmission lines are expensive, and

inefficient for transferring the energy

Environmental Impact Compared to a coal-burning power plant,

geothermal energy has extremely low emissions. 0 lb/MWh of NO

0-0.35 lb/MWh of SO2 (formed from released H2S)

0 (lb/MWh) of Particulate Matter

0-88.8 (lb/MWh) of CO2

*Compared to coal though, we would reduce about 32,000 tons of NO, 78,000 tons of SO2, 17,000 tons of PM, and 16 million tons of CO2 per year.

Environmental impact (con’t)

Noise pollution is not a huge issue by sound level standards

Water Used: 5 gallons of freshwater used per megawatt hour

Water Quality: Fluids are recycle and injected back into reservoirs. Reduces surface water pollution

There are concerns about mercury, arsenic, and lithium pollution from the fluid though

Environmental impact (con’t)

Land Damage: Geothermal plants on avg. use

404m2 of land per gigawatt hour compared to coal facilities’ 3632m2 per gigawatt houre

Can cause subsidence

Induced Seismicity- can be combatted by injecting water into injection wells

Impact on Biodiversity and health?Geothermal plants are often located in scenic and remote areas- many of them protected

With some thought and effort though, they can be intergrated with minimal impact

Olkaria power plant in Kenya and Hells Gate National Park

As a whole, Geothermal energy is a very clean resource and has little health impact

Bibliography Alkaline Hot Springs. Digital image. - MicrobeWiki. N.p., n.d. Web. 24 Sept. 2013.

<http://microbewiki.kenyon.edu/index.php/Alkaline_hot_springs>.

"Environmental Impacts of Geothermal Energy." Union of Concerned Scientists, n.d. Web. 25 Sept. 2013. <http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/environmental-impacts-geothermal-energy.html>.

Fridleiffson, Ingvar B. "The Role of Geothermal Energy in the World." N.p., Aug. 1996. Web. 25 Sept. 2013. <http://geoheat.oit.edu/bulletin/bull17-3/art1.pdf>.

Geo-thermal Energy. Digital image. N.p., n.d. Web. 24 Sept. 2013. <http://static.ddmcdn.com/gif/geothermal-energy-1.jpg>.

"Geothermal Energy: Technologies and Costs." National Geothermal Collaborative, n.d. Web. 24 Sept. 2013. <http://www.geocollaborative.org/publications/Geothermal_Energy_Technologies_and_Costs.pdf>.

"Induced Seismicity." Induced Seismicity. US Department of Energy, n.d. Web. 25 Sept. 2013. <http://esd.lbl.gov/research/projects/induced_seismicity/egs/definition.html>.

Introduction to Geothermal Energy. Digital image. Introduction to Geothermal Energy. N.p., n.d. Web. 24 Sept. 2013. <http://geothermal.marin.org/geopresentation/sld031.htm>.

Kagel, Alyssa, Diana Bates, and Karl Gawell. "A Guide to Geothermal Energy and the Environment." Geothermal Energy Association, Apr. 2007. Web. 25 Sept. 2013. <http://www.geo-energy.org/reports/Environmental%20Guide.pdf>.

Science in a Can, Geothermal EnergyFor Thousands of Years,... Digital image. Science in a Can. N.p., n.d. Web. 24 Sept. 2013.

Shimkus, John. "Top Ten: Geothermal Energy Locations." Energy Digital. WDM Group, n.d. Web. 25 Sept. 2013. <http://www.energydigital.com/top_ten/top-10-business/top-ten-geothermal-energy-locations>.

Volcano Lava. Digital image. N.p., n.d. Web. 25 Sept. 2013. <http://premaantaranga.files.wordpress.com/2009/03/volcano-lava-flow.jpg>.

Wetang'ula, Gabriel, and Benjamin Kubo. "Olkaria Geothermal Energy Project." N.p., n.d. Web. 25 Sept. 2013. <http://www.energytoolbox.org/gcre/bibliography/129_Olkaria_Geothermal_Power_Project_Kenya.pdf>.