What is Geothermal Energy?
Geothermal energy
is the technique of gaining heat as energy source from earth’s surface. In order
to produce electricity, most power plants require steam. Geothermal power
plants use steam which is produced from hot water tanks discovered far below
earth's surface. A turbine is rotated by steam which helps to run a generator
for electricity production. Most power plants are using conventional fuels to
boil water for steam. Earth’s surface holds huge amount of heat which can
produce extremely huge amount of energy than all other natural resources like
oil and gas in the world. Predicted heat extraction in geothermal energy is
very small in comparison to heat content of earth. So, it is renewable.
Types of Geothermal Power
Plant:
Geothermal power plants are
of three types. They are - flash steam, binary cycle and small scale power
plant.
Flash steam power plants: Here, geothermal tanks of water having temperatures higher than
183°C are used. This hot water flows up with its self-pressure through shafts
in the ground. Pressure decreases with its upward flowing and some portion of
hot water boils into steam. The steam is then separated from the water and used
to rotate the turbine in order to generate power. Any excess water and
compressed steam are injected back into the tank which is a significant example
of sustainable resource.
Binary cycle power plants: These plants work on water at lower temperatures of about
108°-182°C. In order to boil a working fluid, these plants utilize the heat of
hot water which is basically an organic compound having lower boiling point. In
the heat exchanger, water fluid is evaporated which helps to rotate a turbine.
For reheating, the water is then injected back into the ground. During whole
process, working fluid and the water are kept separated. So, there is no
possibility of air emissions.
Small-scale power plants: These plants are typically under 5 megawatts. They have good
prospect of extensive application in rural areas as well as a distributed
energy resource. Distributed energy resource is the diversity of small and
flexible power producing technologies which is integrated to develop the
process of the electricity delivery system.
Applications of Geothermal
Energy:
Long time ago, geothermal
energy was used for bathing and space heating. Now, it is known for generating
electricity. It can also be used for industrial processes, purification and
pumping system.
Benefits of Geothermal
Energy:
No fuel is required in
geothermal energy and its capital costs are very significant. So, it is very
cost effective. It is also environmentally friendly, consistent and
sustainable. Historically, geothermal energy is limited to areas close to
boundaries of tectonic plate. Many areas of the world are already using
geothermal energy as a reasonable and ecological solution. At present,
countries like United States, Japan, New Zealand, Italy, Iceland, Mexico, El
Salvador, Philippines, Indonesia and Kenya are generating the most electricity
from geothermal sources. This technology helps to minimize the dependency on
fossil fuels and also reduces the global warming.