Geothermal energy is heat within the earth. The word geothermal comes from the Greek words geo (earth) and therme (heat). Geothermal energy is a renewable energy source because heat is continuously produced inside the earth. People use geothermal heat for bathing, to heat buildings, and to generate electricity.

1. GEOTHERMAL ENERGY

2. WHAT IS GEOTHERMAL ENERGY?
• Geothermal energy is heat within the earth. The word geothermal comes from the
Greek words geo (earth) and therme (heat). Geothermal energy is a
renewable energy source because heat is continuously produced inside the earth.
People use geothermal heat for bathing, to heat buildings, and to generate
electricity.

3. SOURCES
• Geothermal reservoirs are naturally occurring areas of hydrothermal resources.
These reservoirs are deep underground and are largely undetectable above
ground. Geothermal energy finds its way to the earth's surface in three ways:
• Volcanoes and fumaroles (holes in the earth where volcanic gases are released)
• Hot springs
• Geysers
• Most geothermal resources are near the boundaries of the earth’s tectonic plates

4. TYPES OF
GEOTHERMAL POWER
PLANTS

5. Dry Steam Power Plant
• Dry steam plants use hydrothermal fluids that are primarily
steam. The steam travels directly to a turbine, which drives
a generator that produces electricity. The steam eliminates
the need to burn fossil fuels to run the turbine
• Steam technology is still effective today at currently in use
at The Geysers in northern California, the world's largest
single source of geothermal power.

6. FLASH STEAM POWER PLANT
Flash steam plants are the most common type of geothermal power
generation plants in operation today. Fluid at temperatures greater
than 360°F (182°C) is pumped under high pressure into a tank at the
surface held at a much lower pressure, causing some of the fluid to
rapidly vaporize, or "flash." The vapor then drives a turbine, which
drives a generator.
If any liquid remains in the tank, it can be flashed again in a second
tank to extract even more energy.

7. BINARY CYCLE POWER PLANT
• Low to moderately heated (below 400°F) geothermal fluid and a
secondary (hence, "binary") fluid with a much lower boiling point that
water pass through a heat exchanger. Heat from the geothermal fluid
causes the secondary fluid to flash to vapor, which then drives the
turbines and subsequently, the generators.
• Binary cycle power plants are closed-loop systems, and virtually
nothing (except water vapor) is emitted to the atmosphere. Because
resources below 300°F represent the most common geothermal
resource, a significant proportion of geothermal electricity in the future
could come from binary-cycle plants.

8. ADVANTAGES
• Environmentally Friendly
• Renewable
• Huge Potential
• Sustainable / Stable
• Heating and Cooling
• Reliable

9. GEOTHERMAL ENERGY IN INDIA
• In India, exploration and study of geothermal
fields started in 1970. The GSI (Geological
Survey of India) has identified 350 geothermal
energy locations in the country. The most
promising of these is in Puga valley of Ladakh.
The estimated potential for geothermal energy
in India is about 10000 MW.
• There are seven geothermal provinces in India
: the Himalayas, Sohana, West coast,
Cambay, Son-Narmada-Tapi (SONATA),
Godavari, and Mahanadi.