2. What is Geothermal energy?
• The word Geothermal comes from the Greek word
geo (Earth) and therme (heat).
• Geothermal energy is the heat from the earth.
• It’s source lies 6,500km beneath the Earth’s
surface, Core containing hot magma.
3. • Surrounding the core is the mantle, and outer
layer is the crust.
• The crust is not a solid shell but is broken into
pieces called plates, Magma comes close to
Earth’s surface near the edges of these plates.
• Rocks and water beneath the surface around these
region absorbs heat of this magma.
• We can dig wells and can use this heat for various
purposes.
4. History of Geothermal energy
• 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.
5. Finding Geothermal Energy
• Some visible features of geothermal energy are
volcanoes, hot springs, geysers, and fumaroles.
• But we cannot see most of the resources as they
are deep underground.
• Exploration is done by digging well and testing
temp deep underground.
• Most active resources are found along edges of
tectonic plates.
6. • An area called Ring of fire has most of geothermal
activities, this area borders the Pacific Ocean.
7. Uses
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.
9.
10. Indirect use: electricity
production
• Source temperature is higher than 150 degree
Celsius.
• Deep wells are drilled and steam from reservoir is
used to drive turbines and produce electricity.
11. Types of power plants
Flashed steam plant
Dry steam plant
Binary power plant
Hybrid power plant
12. Flashed steam plant
• Hot water at high
pressure when
released from deep
reservoir forms high
pressure steam
(flashed steam).
• This steam drives
turbines.
• This is most common
type of plant operating
today.
14. Dry steam plant
• Usually geysers are
the main source of dry
steam.
• Reservoirs which
produce steam with
small quantity of
water use this type of
plant.
• A rock catcher is used
to protect turbine from
rocks coming along
with steam.
15. Binary power plant
• 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.
16. • 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.
17. Hybrid power plant
• It uses both 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.
18. Enhanced geothermal system
• 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.
19. Advantages
• 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.
20. Cost, Price and Challenges
• 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 be 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.
22. 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 with 3,086 MW of installed
capacity from 77 power plants.
• The Philippines is second highest producer of
geothermal power in the world, with 1,904 MW of
capacity online; geothermal power makes up
approximately 18% of the country's electricity
generation
23. • There is expected rise to 18,500 MW by 2015
as large no of projects are under construction.
24. Geothermal Energy In India
• India has about 10000
MWe of geothermal
power potential which
ean be used.
• More than 300 hot
spring locations have
been identified by
Geological survey of
India, and are grouped
into geothermal
provinces of India.
25. Geothermal Energy and the
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.
Geothermal plants use 404 square meters per
GWh versus 3,622 and 1,335 square kilometres for
coal facilities and wind farms respectively.
• They use 20 litres of freshwater per MW·h versus
over 1000 litres per MW·h for nuclear, coal power
plants.
• It is one of the most eco-friendly technology.
26. References
•
• Www.Wikipedia.com
• The NEED Project , www.NEED.org
• Www.indiaenergyportal.org
• Www.worldenergy.org
