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SEMINAR
HARNESSING ELECTRICAL ENERGYBY GEOTHERMAL SOURCES
Rahul P. Muduli0811013112ELECTRICALSEC-A
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Geothermal energy is thermal energy generated andstored in the Earth. Thermal energy is the energy thatdetermines the temperature of matter.
Earth's geothermal energy originates from the original
formation of the planet (20%) and from radioactive decay ofminerals (80%).
The geothermal gradient, which is the difference intemperature between the core of the planet and its surface,
drives a continuous conduction of thermal energy in theform of heat from the core to the surface.
The adjective geothermal originates from the Greekroots geo , meaning earth, and thermos , meaning heat.
INTRODUCTIONWHAT IS GEOTHERMAL ENERGY
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Developments in alternative energy sourcesThreats of traditional energy resource exhaustionDrive to self-sufficiencyGrowing concern for the environment
Why geothermal energy??
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Technology todayallows for small scaleharnessingeverywhere usingHeat pumps
Different areas havedifferent thermalgradients and thusdifferent utilization
potentialsHigher thermalgradients correspondto areas containingmore geothermalenergy
Where to harness geothermal energy?
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Geothermal field - thermal area where permeablerock formations below ground contain a working fluidwithout which the area could not be exploited on alarge scale
Geothermal field characterizations:• Semi-thermal field- produces water up to 100 oC from drillingdepths of 1-2 km
• Wet hyper-thermal field (water-dominated)- producespressurized water > 100 oC
• Dry hyper-thermal field (vapor-dominated)- produces drysaturated, or slightly superheated steam at P > P atm
By exploiting geothermal fields, particularly hyper-thermal fields, geothermal energy can be harnessedon a large scale
Geothermal Fields
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Distribution of major geothermalenergy reserves
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Semi-thermal fields :- District heating
Building/hot water heatingSidewalk clearing• Farming applicationsEx. Greenhouses in Iceland
• Industrial usages
Hyper-thermal fields (supply high grade heat)• Electric Power Generation
• Natural releases of geothermal energy have been utilized for centuries:Bathing and Therapeutic treatment.
Domestic services (e.g. Cooking, laundry)Mineral extraction
geothermal water can contain useful minerals• Boric acid, sulfur, vitriol or aluminum
Geothermal fields : USAGES
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ExplorationDrillingFluid Collectionand TransmissionEnergy Utilization
Space heating,domestic hot water supplies, air conditioningIndustrial and farming usagesElectric power generation
Exploiting geothermal fieldresources
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Three types of geothermal power plantsconverting hydrothermal fluids to electricity
Dry steamFlashBinary Cycle
Plant installed in a given area dependent on the
type and temperature of the exploited fluid
Areas possessing these gradients are classifiedas geothermal fields and are located only inselected areas of the globe
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First type of geothermal power plant• 1904: First dry steam power plant built in Larderello,
Italy by Prince Piero Ignoe Conti• Considered the most spectacular historical advance
in harnessing geothermal energy
In this type of plant steam moves fromgeothermal wells directly coupled to turbine/generator which then produces electricity
Dry steam electrical powergeneration
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Steam plants use hydrothermal fluids that are primarily
steam. The steam goes directly to a turbine, which drives agenerator that produces electricity. The steam eliminates theneed to burn fossil fuels to run the turbine. (Also eliminatingthe need to transport and store fuels!) This is the oldest typeof geothermal power plant. It was first used at Lardarello inItaly in 1904, and is still very effective.
World’s largest single source of
geothermal power:The Geysers,Northern California
Dry steam electrical power generation
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Most common type of geothermal power plantin operation todayUtilize water-dominated fields with fluidT>182 oCFluid pumped under high pressure to powergeneration equipment where it is sprayed intolow pressure tankPressure reduction upon entering tank causessome fluid to flash (vaporize quickly)Flash vapor drives turbine/generator
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Used in geothermal areas wheregeothermal fluid is at moderatetemperaturesHot geothermal fluid and a binary fluidpass through heat exchangerBinary fluid has much lower boiling point
than water, thus heat from thegeothermal fluid causes binary fluid toflashFlash steam drives turbines/generators
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biggest turbinegenerator,imperialvalley,California
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Places in INDIA
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Installed geothermal electric capacity
CountryCapacity (MW)
2007 [7] Capacity (MW)
2010 [19]
Percentageof nationalproduction
USA 2687 3086 0.3%
Philippines 1969.7 1904 27%
Indonesia 992 1197 3.7%
Mexico 953 958 3%
Italy 810.5 843 1.5%
New Zealand 471.6 628 10%
Iceland 421.2 575 30%
Japan 535.2 536 0.1%
Iran 250 250
El Salvador 204.2 204 25%
Kenya 128.8 167 11.2%
Costa Rica 162.5 166 14%
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Environmental impacts for the installation ofgeothermal power plants are much less thantraditional power plants in regards toLand impacts
Air impactsgroundwater impacts
Aesthetic impacts
Impacts further reduced in systems wheregeothermal waste water and steam is reinsertedinto the ground
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THANK YOU !!
