By Violeta Vasquez
An alternative source to produce heat (or cold) is geothermal energy, coming from within the earth. At the moment its use is not intensive because not all areas of the world have a geothermal resource, however, where it is possible to apply a good exploitation system, it can help reduce dependence on fossil fuels, which are not renewable.
This source of energy has been used since very ancient times and is produced from the heat that accumulates inside the earth, where the temperature increases in proportion to the depth.
Geothermal energy can be extracted from rocks, or from groundwater tables where water is heated and rises to the surface, sometimes in the form of steam, as is the case with geysers.
An advantage of this type of energy is that the waste it produces is few and its environmental impact is less than that caused by oil and coal, that is, the emission of CO2 is low.
It was first used for electrical power in 1904 in Larderello, Italy. Currently, in the world the use of this type of energy amounts to 8000 NW, with the United States being the country that generates the most energy (2,700 NW).
Ways to use geothermal energy
The so-called thermal baths, well known in different parts of the world, take advantage of the very hot water deposits.
In the active areas of the earth's crust, there is geothermal energy with a temperature between 150 and 400 ° C, which through the use of turbines can generate electricity.
Small power plants, or the use of heating in urban distribution systems, use geothermal energy of average temperatures between 70 and 150 ° C.
For domestic or agricultural uses or geothermal air conditioning or in sedimentary basins or urban and rural heating systems, low temperature thermal energy is used, generally with fluids between 20 and 70 ° C.
Implementing a geothermal system is inexpensive, does not require expensive dams or deforestation of forests, and resources of this type are still abundant on earth, so it can be achieved at reasonable prices.
An advantageous way of using geothermal energy is through geothermal air conditioning, both in cooling and heating places such as hospitals, office buildings, apartment blocks, hotels, etc. The Geothermal Energy specialized site explains that the collector technique is used, which are buried in the subsoil through which water circulates, to which glycol is added. In summer this system transfers the excess heat to the subsoil, while in winter the heat is extracted from the ground to heat the environment of the building.
There are water vapor deposits, where geothermal energy is better used but has the disadvantage that it is more complicated and expensive to reinject the water, therefore there is a probability of depletion and contamination of the atmosphere of certain gases that accompany the steam.
In many places where the hot waters emerge, a rotten egg smell is detected, which is due to the emission of hydrogen sulfide that can be lethal in large quantities. The disadvantage of contaminating adjacent waters with substances such as arsenic, ammonia, etc. is added.
In the case of geysers, to be able to create a geothermal field, certain conditions are required such as impermeable rocks, fractured soil, a magnanimous heat source -from 500 to 600 ° C-, and in addition to exploit it, drilling similar to oil extraction is needed .
The Epoch Times