Geothermal Power Plant
Aashish Kumar – 11BEE1076
Aryan Chhabra- 11BEE1112
Antony Albert Raj I – 11BEE1055
Arvind Kumar – 11BEE1092
Irfan Khan – 11BEE1013
Shreyansh Vats – 11BEE1033
Nisha Bhagat – 11BEE1009
Shyamla Kumari – 11BEE1129
What is Geothermal Energy ?
Geothermal Energy is thermal energy generated and stored in the earth.
Thermal energy determines the temperature of the matter.
Earth’s geothermal energy originates from the original formation of the
Planet and from radioactive decay of minerals.
Geothermal Power Plant uses superheated water to generate electricity.
It is a most efficient way or we can say a much
better way to generate electricity because they require no raw materials
and having little or no impact on the environment
Why is geothermal energy a renewable resource?
Because its source is the almost unlimited amount of heat
generated by the Earth's core.
How much does geothermal energy cost per kilowatt-hour (kWh)?
At The Geysers, power is sold at $0.03 to $0.035 per kWh.
A power plant built today would probably require about $0.05 per kWh.
Where is geothermal energy available?
Hydrothermal resources - reservoirs of steam or hot water - are available
primarily in the western states, Alaska, and Hawaii. However, Earth
energy can be tapped almost anywhere with geothermal heat pumps and
direct-use applications. Other enormous and world-wide geothermal
resources - hot dry rock and magma, for example - are awaiting further
What we all know about Geothermal power plant ?
Current worldwide installed capacity is 10,715
megawatts(MW), with the largest capacity in the
United States (3,086 MW).
India has announced a plan to develop the country's first geothermal power facility
Economically Geothermal power requires no fuel, it is therefore immune to fuel cost
Geothermal power is considered to be renewable because any projected
heat extraction is small compared to the Earth's heat content.
The Earth has an internal heat content of 1031 joules.
Further, due to its low emissions geothermal energy is considered to
have excellent potential for mitigation of global warming.
The areas in the world with the higher underground
temperatures are regions with active volcanoes or
geologically young volcanic events.
These “hot spots” occur at tectonic plate boundaries or where
the earth’s crust is thin enough to let the heat through.
The Pacific Rim, with its many active volcanoes, has many
hot spots, along with Alaska, Hawaii, and much of the
western United States.
These regions are also seismically active with earthquakes
and magma movement, which breaks up rock structures and
allows water to circulate. As the water rises to the surface,
natural hot springs and geysers occures.
Geothermal power uses the heat of magma below the
Earth's crust, which comes from radioactive decay
Geothermal heat pumps
Geothermal electric power generation generally uses higher
temperature geothermal resources (above 110◦C)
– Vapour dominated sources – direct steam conversion
– Liquid dominated sources – to separate steam from the
– Low quality resources – using binary power plant
• Electricity generation requires high temperature
resources that can only come from deep underground.
The heat must be carried to the surface by fluid
circulation, either through magma conduits, hot springs,
hydrothermal circulation, oil wells, drilled water wells,
or a combination of these.
• Away from tectonic plate boundaries the geothermal
gradient is 25-30°C per km of depth in most of the world,
and wells would have to be several kilometers deep to
permit electricity generation.
• The quantity and quality of recoverable resources
improves with drilling depth and proximity to tectonic
Geothermal Electricity Production
• Heat from the earth—geothermal energy—heats water that has
seeped into underground reservoirs. These reservoirs can be
tapped for a variety of uses, depending on the temperature of
the water. The energy from high-temperature reservoirs (225°-
600°F) can be used to produce electricity.
• In the United States, geothermal energy has been used to
generate electricity on a large scale since 1960. Through
research and development, geothermal power is becoming
more cost-effective and competitive with fossil fuels.
• There are currently three types of geothermal power plants:
To harness energy ,large holes have to be dug into the earth until a
geothermal hotspot is found.
Pipes are inserted inside these holes through which water is sent
and steam output is obtained.
The production involves two process
1) Converting Geothermal energy into Mechanical energy
2) Converting Mechanical Energy into Electrical Energy
The success of the energy production depends on the temperature
of the plant which depends on the temperature of the rocks in earth.
The water is sent through the injection well and reaches the rocks
and then hot water comes from the production well.
The steam that comes out of the mixture might have dissolved
brine and some dust particles.
Due to the high pressure when it reaches the topmost of the earth
surface it is converted into steam.
The separator is the place where steam that comes from the earth
is made clean by removing the brine and dirt so that they do not
damage the turbine blades.
The high pressure and low pressure steam runs the turbine.
The generator is coupled with turbine to produce electricity.
The condensor is a phase changer where the steam output of the
turbine is given to the condensor and gets converted to hot water.
This hot water is then sent to the cooling tower where it loses it
heat and then sent to the geothermal reservoir for further
production of steam.
TYPES OF GEO-THERMAL
• DIRECT DRY STEAM
• FLASH AND DOUBLE FLASH STEAM CYCLE
• BINARY CYCLE
DIRECT DRY STEAM
• Steam plants use
hydrothermal fluids that
are primarily steam.
• Steam goes directly to a
turbine, which drives a
generator that produces
• Steam eliminates the need
to burn fossil fuels to run
• These plants emit only
excess steam and very
minor amounts of gases.
• Fluid(182°C) is sprayed
into a tank held at a
much lower pressure
than the fluid.
• The vapour then drives
a turbine, which drives
• If any liquid remains in
the tank, it can be
flashed again in a
second tank (double
flash) to extract even
• Moderate-temperature water is
used in it.
• Hot geothermal fluid and a
secondary fluid with a much
lower boiling point than water
pass through a heat exchanger.
• Heat from the geothermal fluid
causes the secondary fluid to
flash to vapour, which then
drives the turbines.
• Because this is a closed-loop
system, nothing is emitted to
• Most efficient for future.
E X T R A C T I O N W E L L
• The function of this extraction well is only to pump up
the hot liquid(here water) from the reservoir.
• This well serves as the feed to the separator.
• It carries the supply from the reservoir that is the original
mixture of water(as mist) and the steam(the vapor).
I N J E C T I O N W E L L
1. The basic idea behind an injector is to inject, or recycle the fluid
(generally water) back to the reservoir to complete the loop.
2. The injected fluid enhances the transmissivity of the rocks and maintains the
3. The injection well has lines coming out from the separator as well as the
condenser and the cooling tower which finally connect together to the main
pipeline back to the reservoir.
4. Also, if the water is to be used for any other purpose than electricity
generation, the supply can be taken from the injection wells as well (i.e. Apart
from that from the reservoir).
• The purpose served by the Vapor-liquid separator(Or simply the
separator) is to separate the vapor-liquid mixture.
• For normal cases, this purpose is served by the gravity.
• The inlet valve feeds the separator with the mixture through the inlet
diffuser(or the distributor).
• The mixtures gradually moves up towards the vapor outlet. During
this process, a large amount of the water content condense-off and
fall below. If some amount of water droplets remain in the vapor,
they strike the de-entrainment mesh pad and fall back.
• The water is then taken off through the outlet.
• The liquid level control monitors the level of liquid in the separator
and maintains the pressure required for it to operate.
Wayang Windu Geothermal power
Inlet steam pressure: 1.02 Mpa
Inlet steam temperature: 181 C
Exhaust pressure: 0.012Mpa
Speed: 3000 rpm
High efficiency blades: increase the
efficiency by 3 %.
Reaction type blades: assure good
Casing: single shell construction:
This construction secure the
vibration stability of the turbine
Drum type construction: Deposition
of corrosive components: eliminated.
Possibility of stress corrosion
Cooling system: Totally
controlled water to air.
Ventilation : Self ventilation
Excitation: Brushless Excitation
Speed: 3000 rpm
Output: 137,500 kVA
Power Factor: 0.8 lag
Condenser And NCG
- Pressure maintained at 0.01 Mpa by NCG removal system.
- NCG (Non Condensable Gas) System: 2 Stages
1. Two 100% capacity ejectors.
2. Two 100% cooling water pumps.
• Consist of two 60% capacity
circulating water pumps.
• Discharge condensate from
the condensor hotwell to the
Geothermal prawn farming
The world’s only geothermally heated
prawn farm was established in 1987 on
the banks of the Waikato River, next to
the Wairākei power station.
Geothermal waste heat is used at Taupō
to cultivate giant river prawns which
require warm temperatures (24–28ºC).
This is a good example of what is
known as ‘cascade use’, where
geothermal heat has a function past its
primary purpose. Cascading improves
the overall efficiency of a resource by
using its waste products. In the case of
the prawn farm, cascading also reduces
the discharge of hot water into the river,
where it can harm aquatic life.
Geothermal energy is also used to heat
sidewalks and roads to prevent freezing in the
winter. Most recently, the Netherlands began
using geothermal energy to keep bike lanes
from freezing in the wintertime.
Geothermal waters are used for heating
greenhouses on a small scale (covering 10
hectares in total), especially for the
commercial, out-of-season production of
vegetables, flowers and fruit.
This includes a large greenhouse (0.8
hectares) for growing orchids for export, and
another set up to grow capsicums with heat
from the Kawerau geothermal field.
Providing Heat For Residential And Commercial Use.
MERITS OF GEOTHERMAL
1) It is a renewable source of energy.
2) By far, it is non-polluting and environment
3) There is no wastage or generation of by-
4) Geothermal energy can be used directly. In
ancient times, people used this source of energy
for heating homes, cooking, etc.
5) Maintenance cost of geothermal power plants is
6) Geothermal power plants don't occupy too much
space and thus help in protecting natural
7) Unlike solar energy, it is not dependent on the
1) Only few sites have the potential of Geothermal Energy.
2) Most of the sites, where geothermal energy is produced,
are far from markets or cities, where it needs to be
3) Total generation potential of this source is too small.
4) There is always a danger of eruption of volcano.
5) Installation cost of steam power plant is very high.
6) There is no guarantee that the amount of energy which
is produced will justify the capital expenditure and
7) It may release some harmful, poisonous gases that can
escape through the holes drilled during construction.