GEOTHERMAL ENERGY | The renewable energy

“Geothermal energy is the heat from the Earth. It’s clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth’s surface, and down even deeper to the extremely high temperatures of molten rock called magma.”

The earth’s core lies almost 4,000 miles beneath the earth’s surface. The double-layered core is made up of very hot molten iron surrounding a solid iron center. Estimates of the temperature of the core range from 5,000 to 11,000 degrees Fahrenheit (F). Heat is continuously produced within the earth by the slow decay of radioactive particles that is natural in all rocks.

Surrounding the earth’s core is the mantle, thought to be partly rock and partly magma. The mantle is about 1,800 miles thick. The outermost layer of the earth, the insulating crust, is not one continuous sheet of rock, like the shell of an egg, but is broken into pieces called plates. These slabs of continents and ocean floor drift apart and push against each other at the rate of about one inch per year in a process called continental drift.

Magma (molten rock) may come quite close to the surface where the crust has been thinned, faulted, or fractured by plate tectonics. When this near-surface heat is transferred to water, a usable form of other- energy is created.

Geothermal energy is called a renewable energy source because the water is replenished by rainfall, and the heat is continuously produced by the earth.

How do we produce geothermal energy?

“In order to obtain enough energy to generate electricity, geothermal power plants rely on the heat that exists a few kilometers below the surface of the Earth. In some areas, the heat can naturally exist underground as pockets steam or hot water.”

What is a geothermal reservoir?

“These geothermal reservoirs of steam or hot water occur naturally where magma comes close enough to the surface to heat ground water trapped in fractured or porous rocks, or where water circulates at great depth along faults.”

Where is geothermal energy found in the world?

“Some visible features of geothermal energy are volcanoes, hot springs, geysers, and fumaroles. But you cannot see most geothermal energy. Usually, geothermal energy is deep underground. There may be no clues above ground to what exists below ground.”

The earth is a hotbed of geothermal energy. The most active geothermal resources are usually found along major plate boundaries where earthquakes and volcanoes are concentrated. Most of the geothermal activity in the world occurs in an area known as the “Ring of Fire.” The Ring of Fire rims the Pacific Ocean and is bounded by Japan, the Philippines, the Aleutian Islands, North America, Central America, and South America.

The top 10 biggest geothermal power plants in the world:-

1-The Geysers Geothermal Complex, California, United States of America

2-Larderello Geothermal Complex, Italy

3-Makban Geothermal Complex, Philippines

4-CalEnergy Generation’s Salton Sea Geothermal Plants, United States


5-Hellisheidi Geothermal Power Plant, Iceland

6-Tiwi Geothermal Complex, Philippines

7-Malitbog Geothermal Power Station, Philippines

8-Wayang Windu Geothermal Power Plant, Indonesia

9-Cerro Prieto Geothermal Power Station, Mexico

10-Darajat Power Station, Indonesia


Water or working fluid is heated (or used directly in case of geothermal dry steam power plants), and then sent through a steam turbine where the thermal energy (heat) is converted to electricity with a generator through a phenomenon called electromagnetic induction.


1)  It is a renewable source of energy.

2)  By far, it is non-polluting and environment-friendly.

3)  There is no wastage or generation of by-products.

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 very less.

6)  Geothermal power plants don’t occupy too much space and thus help in protecting the natural environment.

7)  Unlike solar energy, it is not dependent on the weather conditions.


1)  Only a few sites the 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 consumed.

3)  Total generation potential of this source is too small.

4)  There is always a danger of the eruption of a volcano.

5)  Installation cost of the 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 operations costs.

7)  It may release some harmful, poisonous gases that can escape through the holes drilled during construction.


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