Geothermal resources, hydrothermal resources, liquid dominated systems, geopressured resources, petrothermal systems, magma resources, energy conservation & comparison with other resources, applications of geothermal energy

1. DEPARTMENT OF CHEMICALENGINEERING
CHAPTER-4
“GEOTHERMAL ENERGY”
PROF. DEVARSHI P. TADVI
ASSISTANT PROFESSOR
CHEMICAL ENGINEERING
DEPARTMENT
S S AGRAWAL INSTITUTE OF
ENGINEERING & TECHNOLOGY,
NAVSARI

2. Topics
• What is Geothermal Energy?
• Geothermal resources
• Electricity generation
• How it’s Work?
• Application
• Advantages and Disadvantages
• Geothermal Energy Prospective in India
• Thermal Power Plant

3. What is Geothermal Energy?
• It is the heat energy stored in the earth, generated by natural
sources.
• From the decay of radioactive nuclei that are embedded
within the Earth.
• Fromresidual heat left over from Earths
formation.
• The rest of the energy comes from meteorite impacts.

4. • It’s simply the heat
energy of the earth,
generated by various
natural processes, such
as:
1. heat from when the
planet formed and
accreted, which has
not yet been lost
2. decay of radioactive
elements
3. friction

6. Natural Steam
reservoirs
Hot water
Reservoirs
Geo –pressured
Reservoirs
Different Geothermal Resources
Hot springs
Volcano
Boiling mud pot

7.  The rising hot water
& steam is trapped
in permeable &
porous rocks to
form a geothermal
reservoir.
 Reservoirs can
be discovered
by
 Testing the soil
 Analyzing underground
temperature
Geothermal Reservoir

8. Extraction & uses
 The heat energy can be brought to earth surface by
following ways.
 directly from hot springs/ geysers
 geothermal heat pump
 Uses are broadly classified as:
direct use
indirect use

9. Direct use of Geothermal Energy
 Hot springs, used as spas.
 Heating water at fish farms.
 Provide heat for buildings.
 Raising plants in greenhouses,
drying crops.
 Provides heat to
industrial processes.

10. Indirect use of Geothermal Energy
 Electricity Generation:

11. Electricity Generation
• There are 3 types of power plants:-
 Dry steam power plant
Flash steam power plant
Binary cycle power plant

12. Dry Steam Plants
• Use steam piped
directly from a
geothermal reservoir
to turn the
turbogenerator

13. Flash Steam Plants
• Takes high pressure hot
water from deep inside
the earth and converts it
to steam to drive the
generator turbines
• When the steam cools it
condenses into water
and is injected into the
earth to be used over
and over again.
• Most geothermal plants
are flash steam plants

14. Flash Steam Power Plants are the most common form of geothermal power
plant. The hot water is pumped under great pressure to the surface. When it
reaches the surface the pressure is reduced and as a result some of the water
changes to steam. This produces a ‘blast’ of steam. The cooled water is
returned to the reservoir to be heated by geothermal rocks again.

15. Binary Cycle Power Plants
• Transfers the heat from
geothermal hot water to
another liquid.
• The heat causes the
second liquid to turn to
steam which is used to
drive a generator
turbine.

16. Generation of electricity

17. How does the system work
• Direct Sources function by sending water down a well to be
heated by the Earth’s warmth.
• Then a heat pump is used to take the heat from the
underground water to the substance that heats the house.
• Then after the water it is cooled is injected back into the
Earth.

19. Air conditioning Drying
Greenhouses Aquaculture
Hot water Melting snow
Application of Geothermal energy
Space heating

20. Aquaculture
GreenhousesSpace Heating/Cooling
Snow melting

21. Advantages
• HomegrownEnergy
• Good alternative to fossil fuels
• Less gaseous emission
• Low maintainence
• Saves energy upto 50% in comparison to conventional systems
• Independent of weather
• A sustainable source of energy

22. Disadvantages
• May cause Land Subsidence, this can lead to an increase in seismic
activity.
• Can salinate the soil if the water is not injected back into the reserve
after the heat is extracted.
• Can release H2S.
• Power plants that do not inject the cooled water back into the ground
can release H2S, the “rotten eggs” gas. This gas can cause problems if
large quantities escape because inhaling too much is fatal.

23. PROSPECTS OF GEOTHERMAL ENERGY IN INDIA
• About 6.5% of electricity generation in the world is done by geothermal
energy and India can play an important role in the coming years in this
direction.
• Geological Survey of India has identified about 340 geothermal hot springs in
the country. Most of them are in the low surface temperature range from 37o
C-
90o
C which is suitable for direct heat applications.
• Grouped into seven geothermal provinces. Himalayan (Puga, Chhumathang),
Sahara Valley, Cambay Basin, Son-Narmada-Tapi (SONATA) lineament belt,
West Coast, Godavari basin and Mahanadi basin.
• A new location of geothermal power energy has also been found in Tattapani in
Chhattisgarh. Gujarat is set to tap geothermal electricity through resources which
are available in Cambay between Narmada and Tapi river.
• India’s first geothermal plant to come up in Chhattisgarh. NTPC has already
started exploratory and preparatory work in this area. It has also started talks
with Oil and Natural Gas Corp and international organisations for drilling
operation.

25. Geothermal Power Plant Piping

26. Geothermal Power Plants and the
Environment
• Geothermal power plants
do not burn fuel to
generate electricity so their
emission levels are very low
• Release less that 1% of
carbon dioxide emissions of
a fossil fuel plant
• Use scrubber systems to
clean the air of hydrogen
sulfide
• Emits 97% less acid rain-
causing sulfur compounds
than fossil fuel plants

27. Thank You