It is the energy generated by means of geological heat sources and can be considered an alternative and renewable form of energy, if evaluated in a short time. It is based on the principles of geothermal energy, i.e. the exploitation of the Earth’s natural heat (geothermal gradient) due to the thermal energy released by the natural nuclear decomposition processes of radioactive elements such as uranium, thorium and potassium, naturally contained within the Earth’s core, mantle and crust.
The first use of geothermal energy, for the production of electricity, took place on 4 July 1904 in Italy, thanks to Prince Piero Ginori Conti, who experimented with the first geothermal generator at Larderello in Tuscany, the prelude to real geothermal power stations. Cogeneration was also possible and exploited. Geothermal energy is also used for the production of thermal energy (heat and hot water).
Geothermal energy today accounts for less than 1% of world energy production. However, a study conducted by the Massachusetts Institute of Technology states that the potential geothermal energy contained on our planet is around 12,600,000 ZJ and that with current technologies it would be possible to use “only” 2000 ZJ. However, since world energy consumption amounts to a total of 0.5 ZJ per year, with geothermal alone, according to the MIT study, the planet’s energy needs could be met with clean energy alone for the next 4000 years, making any other non-renewable source currently used useless.