Geothermal Energy

Posted August 29th, 2011 by

Geothermal EnergyGeothermal energy is thermal energy generated and stored in the Earth. Thermal energy is energy that determines the temperature of matter. Earth’s geothermal energy originates from the original formation of the planet, from radioactive decay of minerals and from volcanic activity. The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.

From hot springs, geothermal energy has been used for bathing since Paleolithic times and for space heating since ancient Roman times, but it is now better known for electricity generation. Worldwide, about 10,715 megawatts (MW) of geothermal power is online in 24 countries. An additional 28 gigawatts of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications.

Geothermal power is cost effective, reliable, sustainable, and environmentally friendly, but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, geothermal power has the potential to help mitigate global warming if widely deployed in place of fossil fuels.

The Earth’s geothermal resources are theoretically more than adequate to supply humanity’s energy needs, but only a very small fraction may be profitably exploited. Drilling and exploration for deep resources is very expensive. Forecasts for the future of geothermal power depend on assumptions about technology, energy prices, subsidies, and interest rates.

The adjective geothermal originates from the Greek roots geo, meaning earth, and thermos, meaning heat.

How Geothermal Energy Works
The process of harnessing energy from geothermal activity is fairly simple, yet this depends on how you wish to make the geothermal energy work for you. The two main types of geothermal power come from the center of the earth, and the sun. You probably know that the sun heats the first few feet of the ground we walk on to a significant degree, and then this heat is lost during the night. In the U.K, a few meters beneath the earth’s surface, the temperature hovers around 10 to 15 degrees Celsius. During the winter months this temperature is much greater than the average temperature of the air above the surface. To extract this heat, we are able to run hundreds of meters of piping (in loops – to save space) under the ground. These pipes are then filled with water, and a pump pushes cold water through the pipes to the exit area. The water is collected in a boiler where it can be directly channeled to mechanisms such as underfloor heating, or it can be heated to a higher temperature by the boiler and used for the buildings hot water supply. The heating of the water is more environmentally friendly than heating colder water, as you are closer to the stop temperature from the start. It is said that for every unit of electricity you put into geothermal energy systems, 3 to 4 units are received. Geothermal energy processes are able to work in many different ways, which allows you to harness different amounts of energy for different locations.

Advantages of Geothermal Energy
Geothermal energy provides several advantages to include the following:

1. Significant Cost Savings: Geothermal energy generally involves low running costs since it saves 80% costs over fossil fuels and no fuel is used to generate the power.
2. Reduced Fossil Fuel Reliance: Dependence on fossil fuels decreases with the increase in the use of geothermal energy. With the skyrocketing prices of oil, many countries are pushing companies to adopt these clean sources of energy.
3. Environmental Benefits: Being a renewable source of energy, geothermal energy has helped in reducing global warming and pollution. Moreover, geothermal systems do not create any pollution as it releases some gases from deep within the earth which are not very harmful to the environment.
4. Direct Use: Since ancient times, people having been using this source of energy for bathing, heating homes, preparing food and today geothermal energy is also used for direct heating of homes and offices.
5. Job Creation and Economic Benefits: The use of geothermal energy has created many jobs for local people and increased local economies.

Disadvantages of Geothermal Energy
The following are disadvantages to using geothermal energy:

1. Not Readily Available: Since this type of energy is not widely used, the unavailability of equipment, staff, infrastructure, and training pose hindrances to the installation of geothermal plants across the globe.
2. High Installation Costs: To access geothermal energy, the installation of power plants is required to access steam from deep within the earth. The construction of these plants requires a huge one time investment and requires the hiring of a certified installer. Furthermore, skilled staff must be recruited and relocated to the plant location. Moreover, electricity towers and stations need to be set up to move the power from the geothermal plant to the consumer.
3. Limited Resource: Geothermal sites can run out of steam over a period of time due to a drop in temperature or if too much water is injected to cool the rocks. This may result in a huge loss for companies that have invested heavily in these plants.
4. Suited To Particular Region: Geothermal energy is only suitable for regions where temperature below the earth are quite low and can produce steam over a long period of time. To determine the appropriate region, great research is required which is done by the companies before setting up the plant.
5. May Release Harmful Gases: Geothermal sites may contain some poisonous gases and they can escape deep within the earth, through the holes drilled by the constructors.
As with other alternative energy sources, such as hydroelectric power, solar power, and wind power, geothermal energy is not an ideal solution for an energy source. Rather than rely on geothermal energy as an energy source, we must seek out less costly, more efficient, and more reliable alternative energy.

Image Credit: Recharge

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