Geothermal Energy: An Geothermal Energy: An OverviewOverviewKenneth M. Klemow, Ph.D.Wilkes University

© 2000 Geothermal Education Office

Points to be coveredPoints to be coveredThe deep earth as a thermal sourceDirect uses of geothermal energyTypes of geothermal electrical

generationBenefits of geothermal power

generationCurrent levels of electrical generation

capacity worldwideIssues regarding geothermal

(6940 km)

20-65 km

5-6 km

(2900 km)

© 2000 Geothermal Education Office

Temperature and depthTemperature and depthAverage gradient:

◦2.5 - 3.0oC / 100mVariation:

◦1.0 - 25oC / 100mSo if assuming average, temps at

depth will be:

0 m 15oC

2000 m 70oC

4000 m 120oC

© 2000 Geothermal Education Office

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Geothermal energy is used Geothermal energy is used in two waysin two ways

Electrical generationElectrical generation

www.energywhiz.com

DirectDirect

www.coloradodirectory.com/cottonwoodhotsprings/

Direct uses of geothermal Direct uses of geothermal energyenergy

www.hickerphoto.com

www.strose.edu

www.geothermal-biz.com

www1.eere.energy.gov geothermal.marin.org

http://iga.igg.cnr.it/geo/geoenergy.php

http://iga.igg.cnr.it/geo/geoenergy.php

Types of geothermal electrical Types of geothermal electrical generationgeneration

Dry steamFlash steam

Binary cycle

© 2000 Geothermal Education Office

Geysers dry steam field in Geysers dry steam field in northern Californianorthern California

© 2000 Geothermal Education Office

© 2000 Geothermal Education Office

Flash steam plant in JapanFlash steam plant in Japan

© 2000 Geothermal Education Office

© 2000 Geothermal Education Office

© 2000 Geothermal Education Office

Binary plant in NevadaBinary plant in Nevada

© 2000 Geothermal Education Office

Benefits of geothermal Benefits of geothermal powerpowerProvides safe and reliable power with

little land consumptionRenewable and sustainableProvides constant baseload powerConserves fossil fuelsBenefits local economiesCan be implemented remotelyCan prevent pollution caused by fossil

fuels

© 2000 Geothermal Education Office

1932

2000

© 2000 Geothermal Education Office

Geothermal electrical power Geothermal electrical power output (2010)output (2010)

© 2000 Geothermal Education Office

© 2000 Geothermal Education Office

What is potential for geothermal What is potential for geothermal energy development?energy development?Geothermal power could serve

100% of the electrical needs of 39 countries (over 620,000,000 people) in Africa, Central/ South America and the Pacific.

(Source:www.geotherm.org/PotentialReport.htm link)

What is potential for geothermal What is potential for geothermal energy development?energy development?Using current technology, geothermal

energy from already-identified reservoirs can contribute 10% of U.S. energy supply.

Inventory can grow with more exploration.Entire world resource base of geothermal

energy calculated to be larger than those of coal, oil, gas and uranium combined.

Further research and experience will improve geothermal resource base.

geothermal.marin.org/

What is potential for geothermal What is potential for geothermal energy development?energy development?According to Geothermal Energy

Association (GEA), geothermal resources could supply over 30,000 MW of power by 2025

Equivalent to 6 percent of today's total U.S. electricity needs, and equal to 100% of the electricity generated in California, Nevada and Idaho.

geothermal.marin.org/

Employment in Employment in geothermal?geothermal?

http://www.greenjobs.com/Public/images/geothermal-jobs.gif

Location of geothermal Location of geothermal potential in USpotential in US

www.nwcommunityenergy.org

Geothermal heat pumpsGeothermal heat pumps

© 2000 Geothermal Education Office

Benefits of geothermal heat Benefits of geothermal heat pumpspumps

Can be used almost anywhere worldwide

Are energy and cost efficientConserve fossil fuel resourcesProvide clean heating and cooling;

no emissions from burning fuels

Deployment: 400,000 units in U.S.

Yield: 1500 thermal mW of heating and cooling

Deployment: 400,000 units in U.S.

Yield: 1500 thermal mW of heating and cooling

Any environmental Any environmental problems?problems?

Impact Probability of occurring

Severity of consequences

Air quality pollution L MSurface water pollution M MUnderground pollution L MLand subsidence L L-MHigh noise levels H L-MWell blow-outs L L-MConflicts with cultural and archaeological features

L-M M-H

Social-economic problems L LChemical or thermal pollution L M-HSolid waste disposal M M-H

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One clear environmental One clear environmental benefitbenefit

So, is geothermal the answer So, is geothermal the answer to our energy concerns?to our energy concerns?

You tell me!