Geothermal energy is heat energy generated and stored in the Earth. It can be used directly for heating spaces and water or to generate electricity. The three main types of geothermal power plants are flashed steam, dry steam, and binary cycle plants. Geothermal energy has many benefits like being renewable, reliable, and reducing greenhouse gas emissions. However, it also has challenges like high initial costs and possible induced seismic activity from enhanced geothermal systems. Currently the largest users of geothermal energy are the United States, Philippines, and Indonesia, but its global capacity is growing as new projects are developed.

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2. Contents
 Introduction
 History of geothermal energy
 Geothermal Reservoirs
 Uses of Geothermal Energy
 Types of geothermal power plants
 Pro and Cons
 Cost, price and challenges
 Geothermal Energy in world and srilanka
 Conclusion

3. What is geothermal energy..?
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• It is simply the heat energy of the earth, generated by various natural
processes,
such as ;
 From the decay of radio active nuclei embedded within the
earth
 From residual heat left over from earths formation.
 The rest of the energy comes from meteorite impacts

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• Geo thermal energy is contained in the rock and fluids beneath the
Earth’s crust.
• It can be found from shallow grounds to several miles below the
surface and even farther down to the extremely hot molten rock
called magma.

5. History of geothermal energy
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• The use of geothermal energy for heating purpose is not new.
• Ancient people used it for heating and bathing through hot springs.
• Using geothermal energy to produce electricity is a new industry.
• A group of Italians first used it in 1904. The Italians used the natural steam
erupting from the earth to power a turbine generator
.

6. Geothermal Reservoirs
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• Reservoirs can be suspected in the areas where we find volcanoes, hot springs,
geysers, and fumaroles.
• But we can not see most of the resources as they are deep underground.
• Exploration is done by digging well and testing temperature deep underground.
• Most active resources are found along edges of tectonic plates.

7. Uses
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• Direct use – geothermal
heating and heat pumps
• Indirect use – electricity
production

8. Direct use
• Heat is directly used.
• Heat is extracted from low temperature source, <150 degree
Celsius.
• It can be used for space heating, industrial processes, drying
crops, hot water supply, melting snow.
• For space heating, heat pump is used.
• It uses little energy for heating thus saves money and reduce
pollution.
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9. Indirect use – electricity production
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• Source temperature is higher than 150 degree Celsius.
• Deep wells are drilled and steam from reservoir is used to drive
turbines and produce electricity.

10. Types of power plant
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• Flashed steam
plants
• Dry steam plants
• Binary power plant
• Hybrid power plant

11. Flashed steam plant
• The hot water is pumped under great
pressure to the surface.
• Pressure is reduced and some water
changes into steam
• This produces blast of a steam which
powers the generator.
• This is most common type of plant
operating today.
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12. Dry steam plant
• Usually geysers are the main
source of dry steam.
• Reservoirs which produce steam
with small quantity of water
uses this type of plant.
• A rock catcher is used to protect
turbine from rocks coming
along with steam.
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13. Binary power plant
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• In this the geothermal water is passed through a heat exchanger
where its heat is transferred to a secondary liquid.
• Liquids having lower boiling point are used as secondary liquid such as
isobutene, isopentane or ammonia-water mixture.
• The vapour of secondary liquid are used to rotate turbines.
• The binary system is useful in geothermal reservoirs which are
relatively low in temperature.
• Heat loss is minimum as system is completely closed.

14. • Hot water is immediately recycled back into the reservoir
.
• The working fluid is also condensed back to the liquid and used over
and over again.
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15. Hybrid power plant
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• It uses now boiling
water as well as
steam.
• Steam is directly is
used as used in
flashed steam plant.
• While energy of hot
water is used through
secondary liquid as
used in Binary
system.

16. Enhanced geothermal system
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• It refers to a variety of engineering techniques used to artificially create
hydrothermal resources.
• In this the drilling is done in hot dry rocks, and cold water at high pressure is
pumped in.
• As water travels through cracks in hot dry rock it’s temperature is increased.
• Now This very hot water is collected back through another drilled hole,
converted into steam and used.
• This is very promising technology but is still in it's development stage.
• Risk of seismic activities could increase, due to artificially fracturing the
underground rocks.

18. Advantages
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• Geothermal energy does not produce any pollution, and does not
contribute to the greenhouse effect.
• The power stations are compact, so there is not much impact on the
environment.
• No fuel is needed.
• Once you’ve built a geothermal power station, the energy is almost
free.
• It may need a little energy to run a pump, but this
can be taken from the energy being generated.

19. Disadvantages
• Not widespread source of energy
• High installation costs
• Can run out of steam
• May release harmful gases
• Transportation
• Earthquakes

20. Cost, price and challenges
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• Since it does not use any fuel hence it's cost is unaffected by price
fluctuations.
• primary prices are bit high but once the capital costs have been
recovered price of power can decrease.
• Most of the cost is related to resource exploration and plant
construction.
• Drilling Costs alone account for as much as one-third of total plant cost
because rocks In geothermal areas are usually extremely hard and hot.
• Geothermal power plants must be located near a reservoir because it
difficult to transport steam or hot water over distances.

21. Barriers
• Finding a suitable build location.
• Exploration stage can he extremely capital intensive and
of high-risk.
• Some areas of land may have the sufficient hot rocks to
supply hot water to a power station. But many of these
areas are located in harsh areas of the world (near the
poles), or high up in mountains.
• Harmful gases can escape from deep within the earth.

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Geothermal energy in world
• 10,715 megawatts (MW) of geothermal power in 24 countries is online.
• The United States led the world in geothermal electricity production.
• The Philippines is second highest producer of geothermal power in the
world. geothermal power makes up approximately 18% of the country’s
electricity generation.
• Global geothermal power capacity is expected to rise to just over 17 GW
by 2023, with the biggest capacity additions expected in Indonesia,
Kenya, Philippines and turkey.

23. Top 10 geothermal countries in 2019
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24. • An aria called ring of fire has most of geothermal activities, this area
borders the pacific ocean.
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• There is expected rise to 15 GW by 2020 as large no of projects
are under construction.

25. Geothermal power in Srilanka
 As srilanka has seven major hot springs, planning and mapping has been
made for the construction of a first ever geothermal power plant in
Srilanka.
 The mapping between Trincomalee and Pussangoda has been completed
and final report is to be made.
 The construction could begin thereafter.

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Geothermal energy effects on environment
• Geothermal energy does little damage to the environment, with very
less CO2 emission.
• Transportation of fuel is not required as they are located on top of
there fuel.
• Geothermal has minimal land requirements.
• It is one of the most eco-friendly technology.

27. Conclusion
• Geothermal heating system can replace fossil fuel heating system in a
particular area.
• Annual costs for common heating purposes can be reduced by more
than 60%.
• Continued energy shortages have created added interest in geothermal
energy for power generation.
• Geothermal energy appears to be a partial solution to our energy
needs.

28. Thank You
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