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The geothermic energy
The geothermic energy is the energy generated by geo logical sources of heat and it can be considerated a form of renewed energy.
Sometimes the word “geotermia” (which really means the speciality of geophysics concerning the world heat) is used to show the exploitation of geothermic energy. The world natural heat is the natural energy which has always accompanied human history since its beginning. The same biological life was probably born in particular environment conditions: “between water and fire”.
The world temperatures are rising gradually going into depth, on average every 100 metres the stones temperature rises up of 3°C (so 30°C every km and 300°C every 10 km). But this is valid only for the terrestrial crust, in the rest of the world the increase of the temperature in relation to the depth (called geothermic gradient) is sensitively smaller. Particularly in the middle section between the crust and the external nucleus the geothermic gradient follows a regular course (0.3°C/km and 0.8°C/km).
Some particular zones have a subsoil temperature higher than the average, this phenomenon is caused by volcanic phenomena.
In this hot zones the energy can be simply recovered by geotermia. Geotermia means to lead the vapours which come from water subsoil source to special turbines which produce electric energy and they use water vapour again for the heating or the greenhouse growing.
The main applications of natural vapour which comes from the subsoil are two :


They often put in some cold water in the depth to increase the production of water steam. This is a useful method to preserve the flow of the water steam steady. In this way the powerhouse makes the waterwheel work at full blast and it produces much glow constantly. Geothermal energy remains anyhow an off-centre power source and it is used only in a few places in the world, where the environment enables to do this.
It’s the energetic fortune of Iceland, which bases all the power source on the hot water in the earth and the cold air.
The biggest geothermical complex in the world is situated in California, called "The Geysers" (this wiring has got a 1400 MW potential, enough to satisfy the power request of San Francisco). Italy has exploited geothermal energy since the beginning of XX century and has used it by means of powerhouses able to exploit the vapour energy. In Italy this type of powerhouses is concentrated in Tuscany (Pisa, Siena and Grosseto).
In Larderello we can find one of the first Geothermal powerhouses in the world: the first experiments of prince Piero Ginoro-Conti (1904).
The working of Geothermal Powerhouse is rather easy. The vapour flow moves the waterwheel, the mechanical energy of which is transformed in electricity by means of an oscillator system. From the Tuscan experience you can make positive and negative conclusions about the study of the earth internal heat and geothermal energy.
The geothermal sources of energy receive two criticisms: The typical unpleasant smell of rotten eggs comes out of the geothermic stations to gether with the vapour, which is caused by hydrogen sulphide. It is an unfavourable problem for the people living near the geothermic station, but it is also an easy problem to solve with the installation of particular filters diminishing the exiting vapours.
The outer impact of the geothermic stations can cause some landscape problems. The station, in fact, is like a muddle of ugly whirlwinds. An image similar to one of many industrial areas. The landscape problem can be solved by combining the functional approach of the engineering projects with the ones of a respectful architecture of the landscape and the common sense of aesthetism.
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