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Geothermal Energy

By: EconomyWatch Date: 30 April 2010

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Introduction

Geothermal Energy is essentially the heat that comes from within the Blue Planet, the Earth. The word 'geothermal' itself is derived from two Greek words. 'Geo' implies earth. 'Therme' implies heat. The hot water and steam produced within the Earth can be harnessed for electricity generation and heating of buildings.Geothermal Energy generated by the Earth's interior is renewable energy.

Location of Geothermal Energy

Geothermal reservoirs are mostly situated deep inside the Earth. It may be noted that the so called 'ring of fire' of the Earth envelopes the Pacific rim. Geothermal energy sometimes finds a way out in the following forms.

Volcanoes
Geysers.
Fumaroles (holes which release volcanic gases)
Hot springs
The majority of the active geothermal resources can be found along the main plate boundaries. These areas are marked by heightened volcanic activities and earthquakes. Ring of Fire is one such zone.

Magma on coming up close to the Earth's surface heats up the ground water. This water is at times trapped in the porous variety of rocks. They may also flow along faults and fractured rock surfaces. They become hydrothermal resources due the heating effect of the magma.

Big hydrothermal resources, which occur naturally, are referred to as geothermal reservoirs. Geologists make use of various methods for the determination of existence of geothermal reservoirs.

USA's geothermal reservoirs are mostly situated in its western states, Hawaii and Alaska. California generates the highest amount of electricity from the usage of geothermal energy. 'Geysers dry steam reservoir' (of northern California) is world's biggest dry steam field, known till date. Electricity production has been going on there from 1960.

Geothermal Energy benefits

Benefits of geothermal energy lie in its applications. Three principal geothermal energy uses are listed below.
Direct Usage and Heating systems: Here hot water is used from reservoirs and springs near the Earth's surface
Geothermal heat pumps: They make use of Earth's constant temperature for heating (cooling) buildings in winter (summer). Geothermal heat pumps are cost-effective, energy-efficient and environmentally clean means of temperature control
Generation of Electricity: Here steam or water at excessively high temperatures in needed. The temperature ranges from 300 degrees Fahrenheit to 700 degrees Fahrenheit. Geothermal power plants usually are build in areas where there exists geothermal reservoirs within a couple of miles of the Earth's surface

Environmental aspect of Geothermal Energy

Usage of geothermal energy for heating applications has no adverse environmental impact. Geothermal power plants need not burn any kind of fuel for electricity generation. Hence these plants have negligible emission levels.

It has been seen that a geothermal energy plant's carbon dioxide emissions stays within three percent of that in a fossil fuel based plant.

Geothermal plants make use of scrubber systems for cleaning out hydrogen sulfide from the air. Hydrogen sulfide occurs naturally in hot water streams. After the usage of the water and steam in its production process the geothermal plants send them back inside the Earth.

A geothermal plant's emission of acid rain causing sulfur components is 97 percent less than that by a fossil fuel plant.