Geothermal energy in Larderello, in the province of Siena
For geothermal energy we mean the heat present in the deepest layers of the earth's crust generated by the natural decay processes of the radioactive elements present in the soil: uranium, thorium and potassium above all. A geothermal power plant is a plant capable of exploiting thisgeothermal energy to produce electricity.
Theoretically, a lot of electricity could be produced. Just think that, according to the calculations of scientists, thethermal energy contained within the first 5 km depth of the earth's crust is considerably higher than current world needs. In practice, however, it is a question of very dispersed energy and difficult to recover under economically advantageous conditions. For this reason the exploitation of geothermal energy for the production of electricity it occurs only in some areas where the thermal gradient is clearly higher than the average one.
And in Italy? According to ISPRA data (see the report 'The production of electricity from renewable source plants in Italy') the geothermal sources powered by geothermal energy in Italy they have remained practically unchanged over time. The geothermal power installed at the end of 2012 represented only 1.6% of the gross power of all plants powered by renewable accounts in Italy. At the same time, gross efficient power reached around 772 MW in 2012 compared to 626 MW in 2000, with a growth rate of around 2%.
The first Italian geothermal plants date back to the early 1900s, all located in Tuscany in the provinces of Pisa, Siena and Grosseto. In Larderello, a fraction of the Municipality of Pomarance, in the province of Siena, in 1904 there was the first attempt to produce electricity from the energy contained in the steam. In 1913 the first geothermal power plant with an installed power of 250 kW was started, which had already reached 127,650 kW in 1942.
Compared to other renewable sources, the main advantages ofgeothermal energy are the relative constancy over time and the absence of daytime or seasonal weather fluctuations. Furthermore, a geothermal power plant can be of high economic interest in areas characterized by thermal anomalies due to the so-called 'secondary volcanism'. The disadvantages of a geothermal plant are mainly related to costs (research and drilling of wells, maintenance of the elements), which are much higher than those of a plant of the same type fueled with conventional fuels.