Energy

Energy directly from the Earth

The Earth has its own internal energy, that is responsible for the dynamics of our planet, and volcanic activity is its most evident example, however, this energy also spreads silently and continuously towards the surface in the form of heat: this occurs in every spot of the Earth, even in those areas which do not seem to have any volcanic or geologic activity. Deeper and deeper into the subsoil, the rock temperatures increase with a gradient of 1°C every 33 m in depth on average, even though there are areas which are particularly active, where the temperature increase is more consistent (as for example in volcanic areas): in these particular areas, the so called geothermal fields, the energy found deep in the Earth is exploited to produce electric power. However, this requires very high temperatures, so it is possible only in some fields, called high enthalpy fields (or high temperature fields). The Earth's internal heat can be exploited also when the temperatures are not very high, not for the production of electricity but to obtain heat for domestic heating or for other industrial uses (refer to the special report on geothermal energy). If special devices such as heat pumps are connected to the process to “capture” endogenous heat, an “indirect” use of thermal energy of the Earth becomes possible , and much lower temperatures of “direct” geothermal energy can be exploited: and therefore there is the possibility of a greater diffusion of this use of geothermal energy also in areas without the particular geological conditions of the geothermal fields.