Geothermal Energy

A Renewable Source


Many ancient people used hot mineral springs for bathing, cooking, and heating. Today it is being used for all other reasons, such as agriculture, and is believed to have healing power by some people. Not only that, but geothermal energy is used to produce electricity , as it has become a new industry.

The idea originated by a group of Italians who built an electric generator which was powered by the natural steam from the Earth, in 1904. The first attempt t develop a geothermal power was in California, USA in 1922. Even though this was not successful, later a small hydrothermal plant opened in the same place in 1960. Now days there are 21 countries who use geothermal energy to produce electricity.


The term 'Geothermal' originates from Greek words, "geo," meaning earth, and "therm," meaning heat, which basically means it is the use of Earth's heat. It is a clean and suitable energy. Resources of this energy include, shallow ground, hot water, hot rock found beneath the Earth's surface, and where there are high temperatures of molten rock, called magma. This is a very reliable way of electric production, because of the constant temperature of 10-16 degrees centigrade (50- 60 degrees). For this reason, it can be used during any season throughout the year.


The heat that geothermal energy uses is produced mainly by the radioactive decay of potassium, thorium, and uranium in Earth's crust and mantle, and also by the fiction generated along the tectonic plates. The amount of energy that is usable, depends on the depth of the extraction.There are three types of technologies used for different productions of energy. They are geothermal electricity production, geothermal direct use, and geothermal heat pumps.

Geothermal Electricity Production

Most power plants need steam to generate electricity. Unlike many power plants that still use fossil fuels to boil water for steam, geothermal power plants use steam produced from reservoirs of hot water found below Earth's surface. There are three types of geothermal power plants which includes dry steam, flash steam, and binary cycle.

Dry steam: The steam is piped directly from underground wells to power plant, where it is directed into a turbine unit.

Flash steam: These are the most common power plants. They use reservoirs of water with temperatures greater than 360°F (182°C). The hot water flows up through wells under its own pressure. As it flows upward, the pressure decreases and some of the hot water boils into steam. The steam is separated, and the leftover water is put back into the reservoir.

Binary cycle: This power plant operates on water at lower temperatures of 225°-360°F (107°-182°C). The use heat from the hot water to boil a working fluid (an organic compound with a low boiling point). This fluid is vaporized in a heat converter and is used t turn a turbine. The water is put back to the ground to be reheated and reused

Geothermal Direct Use

This use dates back to when people used hot springs for bathing, cooking food, and etc. Today hot springs are used as spas.

For this system, a well is drilled into a geothermal reservoir supplying a steady system for hot water. Once the water is brought up the well, a mechanical system, a heat converter, and controls deliver the heat directly for use. The uses of geothermal hot water include, heating buildings, raising plants in greenhouses, and in agriculture.

Geothermal Heat Pumps

Geothermal heat pumps take advantage of the constant temperature found beneath earth's surface to heat and cool buildings. The heat pumps consist of three parts including the ground heat exchanger, the heat pump unit, and the air delivery system. The heat exchanger is a system of pipes called a loop, which is buried in the shallow ground near the building. A fluid (mixture of water & antifreeze solution) circulates through the pipes to absorb or release heat within the ground.

During winter, the heat pumps release heat from the heat exchanger and pumps it to the indoor delivery system. However, during summer, the process is reversed, and the heat pump removes heat from the indoor air, into the heat exchanger. This removed heat can be used for other heating purposes, like water.

Geothermal Power - how it works?


One school in Iowa, USA uses geothermal energy as the main source of their electrical production.


  • Webster City Middle School


  • The geothermal heating reduces noise, is a cleaner source, and is easier to maintain the old system.
  • The system saves the district $7,000 in annual energy costs.


  • Webster City's vertical system consists of 385 bores ranging from 100 to 300 feet deep. Water circulating through pipes is kept warm or cool by the constant temperatures in the earth.

Not only is geothermal energy used in schools, but to also power houses, buildings, and colleges. The above school is located in America, but this energy is used in Canada as well. But, so far the largest resources for geothermal power in Canada are located in British Columbia, Yukon, and Alberta. One of the companies that provides with geothermal energy in Canada is Next Energy.


There are many advantages to using the renewable geothermal energy which includes the following:-

  • Quite
  • Dependable
  • Save money
  • No combustion
  • Less energy used
  • Economic benefits
  • It's high heat source
  • Less greenhouse gases
  • Reduced dependence on fossil fuels, and other resources.


To every discovery there is a disadvantage to it, and so does geothermal energy, but it has a few of them which includes:-
  • High installation costs
  • Sites may run out of steam
  • Only available to certain regions
  • Method of extraction may release hazardous gases & minerals.


  • Geothermal energy is the main source in Iceland
  • Geothermal energy can be found in the form of volcanoes, hot springs, and geysers
  • Geothermal energy, unlike other renewable sources, does not depend on the sun
  • Power stations are small, therefore there is less impact on the environment
  • Geothermal energy is extremely efficient (almost 100%) energy source, where only the loss of energy is from the turbine friction.
  • Geothermal systems have a longer life cycle: 25 years for the mechanical equipment and 50+ years for the ground loop
  • The largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California, USA.