Geothermal energy
Priyanka Devan
It is the heat within the earth. The word geothermal comes from the two Greek words. They are geo (earth) and therme (heat). It is also a renewable source of energy because, heat is continuously produced inside the earth. Some people use geothermal heat for domestic purposes like bathing, generate electricity and to heat building.
The slow decay of radioactive particles in the core produces geothermal energy.The earth has four major parts ,they are
- An inner core of solid iron.
- An outer core of hot molten rock called magma.
- A mantle of magma and rock.
- A crust of solid rock
The temperature of the earth’s inner core is about 10,800 degrees Fahrenheit . Temperatures in the mantle is about 392°F to 7,230°F.
Earth’s crust is broken into several pieces. They are called tectonic plates. Magma comes out close near the edges of these plates, where many volcanoes occur. Lava that erupts from volcanoes is partly magma. Water and rocks absorb heat from magma deep underground. They are found deeper underground and they have the highest temperatures.
How is it Used?
It has been used in several countries for thousands of years.For heating systems and for cooking . The underground geothermal reservoirs of heated water and steam can be used for electricity generation and for also other heating and cooling applications.
An example of heating and cooling is where a geothermal heat pump is installed. It is for about10 feet underground. These pipes are filled with with water or an antifreeze solution. This liquid is pumped around the closed loop of pipes. These heat pump systems help to cool down the buildings in summer. It also maintains warmth in summer. This is done by absorbing the earth’s heat while the water circulates back into the building.
Geothermal water has been used to help grow plants in greenhouses, for heating in homes. It can also be piped under roads to melt snow.
How is Geothermal Energy Produced?
Wells up to a mile deep or more are drilled into underground reservoirs .It taps into the geothermal resources. These resources can be exploited from naturally occurring rock, heat, or through enhanced geothermal systems and water permeability. These enhance or create geothermal resources through a process called hydraulic stimulation. These geothermal resources, whether it is natural or enhanced, drive turbines linked to electricity generators and generate electricity.
The first recorded case of geothermal heat which is used for producing electricity was in Italy in 1904. Yet, this heat has been used for bathing since the Palaeolithic Age.
What are the Advantages and Disadvantages?
The main advantages of geothermal energy are environmental features. It produces just one-sixth of the carbon dioxide emitted by a clean natural-gas power plant.
Geothermal energy is cheaper than that of conventional energy.It helps to save of as much as 80% compared with fossil fuels. It is constantly available.
Despite being inexpensive, sustainable and environment-friendly, geothermal is not without its drawbacks .Its production is limited to areas near tectonic plate boundaries. Moreover, some locations may cool down after decades of use.
Even though it is cheaper than fossil fuels. Once a plant has been built, the drilling and exploration of these sites is expensive. This is in part due to the amount of wear experienced by drills and other tools in such aggressive environments.
Geothermal plants release hydrogen sulphide , which is a gas that smells like rotten eggs. But some geothermal fluids contain low levels of toxic materials which need to be disposed of.
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Check your knowledge
20-25 years
Geothermal heat pumps last significantly longer than conventional equipment. They typically last 20-25 years. In
contrast, conventional furnaces generally last anywhere between 15 and 20 years, and central air conditioners last 10
to 15 years.
When done properly, yes. As with any industrial project there are risks involved, but when geothermal
energy is extracted from the right location it is not dangerous. Geothermal energy, or “earth heat”, was
enjoyed by our ancestors as they used hot springs for warmth and cleansing.
It requires trenches at least four feet deep. The most common layouts either use two pipes, one buried
at six feet, and the other at four feet, or two pipes placed side-by-side at five feet in the ground in a two-
foot wide trench.
Soils with a high water content and high bulk density are the best conductors and therefore are the
most suitable for geothermal heat pumps.
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