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.
⢠Itâs source lies 6,500km beneath the Earthâs
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
Earthâs 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
ď Direct use: geothermal heating and heat pumps
ď 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
ď Flashed steam plant
ď Dry steam plant
ď Binary power plant
ď 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
ammoniaâwater 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 itâs
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 itâs
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 itâs 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
â˘
⢠Www.Wikipedia.com
⢠The NEED Project , www.NEED.org
⢠Www.indiaenergyportal.org
⢠Www.worldenergy.org