Geothermal Energy for Kids
- The term ‘geo’ means earth and ‘thermal’ means heat. So the heat energy obtained from the earth’s crust is called geothermal energy.
- Geothermal energy is a type of energy which converts the natural heat from the Earth’s crust into electricity.
- It is the heat energy produced by the hot rocks underground.
- Energy trapped from inside the earth is called geothermal energy.
Where is geothermal energy found
As we all know that we live in the outer surface of the earth i.e. the “Crust”. Which is 3 to 5 miles thick under the oceans and 15 to 35 miles thick on the continents. Below the crust of the earth are the hot molten rocks called the magma that forms the “mantle” and is about 1,800 miles thick. Below this layer is the hot solid rock and this layer is called the “core” of the earth.
Earth’s core is the place where high concentrated geothermal energy is being produced. The temperature prevailing in that region is hotter than the sun’s surface. This heat is produced by the continuous decay of the radioactive materials and by the earth’s original formation.
The layer called the crust which we live in is broken into pieces called the plates. Volcanoes occur when the underlying magma makes its way to the crust through the edges of these plates. The other forms include fumaroles – holes where a volcanic gas gets released. Hot springs – the geothermal heated ground water emerges from the ground to the surface. Geysers
The resources are commonly found to be more active along the plate boundaries. They call this area as “Ring of fire” and this encircles the Pacific Ocean. This has a horse shoe shape, the volcanic eruptions and earthquakes are more concentrated.
Geothermal energy can be extracted from the ground by two main systems
Geothermal plants: this plants use the heat deep inside the earth to generate electricity.
Geothermal heat pumps: These pumps use the heat near the surface of the earth to heat water or to heat up the buildings.
How a geothermal plant functions:
- The water that reaches the porous rock are heated up to high temperature. This hot water is pumped from deep inside the earth through a well under high pressure.
- The pressure is dropped when the water reaches the surface of the earth and this makes the water to vaporize.
- This steam spins the turbines that are connected to a generator to produce electricity.
- The steam then gets cooled down in the cooling tower, condenses into water.
- The cooled water is then pumped back into the earth to continue the process.
How a geothermal heat pump functions
- As mentioned above this pump uses the hot water from just below the surface of the earth.
- The temperature is 50 to 60°F constantly
- The water runs through a loop of pipes.
- During winter, the water heats up as it travels through the parts of the loop that is being buried underground.
- Once it reaches above it transfers the heat to the buildings of office space.
- Once it cools down it is pumped back to get heated up again.
- During summer the process reverses.
- These are energy efficient and cost effective.
- Solar power plant – depends on sun and can’t function at night.
- Wind power plant – depends on the flow of air.
- Hydro power plant – depends on water can’t function during drought.
- Biomass power - depends on the supply of fuel and can contribute to green house gases.
- Geothermal power plant- depends on earth and hence it is available all time.
Geothermal Energy & the Environment
- We all know that the power plants emit lot of materials like green house gases, water that is harmful to the environment.
- Whereas geothermal plants contribute very minimal or negligible amount of harmful waste emission.
- Geothermal power plants don’t burn anything to generate electricity.
- Annually more than $117 million benefits are got by the public of California and Nevada from the clean energy produced by geothermal plant.
Geothermal plant emission
- Carbon dioxide – 5%
- Sulphur dioxide- 1%
- Nitrous oxide - > 1%.
COUNTRIES INSTALLED CAPACITY TOATAL ENERGY PRODUCED
The United States 3,086 MW 0.3%
The Philippines 1,904 MW 27%
Indonesia 1,197 MW 3.7%
Mexico 958 MW 3%
Italy 843 MW 10%
New Zealand 700 MW 10%
Iceland 575 MW 30%
Japan 536 MW 3%
El Salvador 204 MW 14%
Kenya 167MW MW 11.2%