L’energia geotermica sfrutta le forze endogene presenti nel sottosuolo di regioni caratterizzate da una geologia favorevole, per la produzione prevalente di energia elettrica. Il principio si fonda sullo sfruttamento di potenti getti di vapore acqueo ad alta temperatura che vengono liberati attraverso la perforazione di spessi strati rocciosi che li imprigionano. Il fenomeno avviene generalmente in corrispondenza di regioni vulcaniche, perché qui è maggiore la possibilità di incontrare rocce ad alta temperatura ed a modesta profondità.
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The most
important geotermic area in Italy is placed in Larderello,
Tuscany. This geotermic region, is located in the belt of
the Tuscan Pre Appennines, respectivenly separated by
Cecina River and Flora River. Morfologically, the area is
represented by hills and low mountains, with peaks
controlled by erosive process. The higher mountains
rigdes, also represent tectonic highs from era. In the
region, in late Tertiary and Quaternary, a complex post
orogenic vulcanic phenomena occurred. Here, the magmatism is evidenced by widespread volcanic activity leading to the effusion of generally acid lavas and ignimbites. Later a basic sequence in vulcanic rock had place and covered the older magmatic rocks. The rigid dislocations related to both the post orogenic collapse, and the vulcanotectonics are of considerable importance in the structural framework of the region. Also, there is a marked thermal anomaly in the central part of the region, especially close to the southern edge of the volcanic massif. The geothermal gradient is generally higher. |
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Cartina dove è ubicata la zona interessata dai soffioni boraciferi, sotto schema del sistema geotermico
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The fluid from
the wells of the boraciferous region, generally consists
of a mixture of steam and gas.Temperature of the fluid,
varies considerably a minimum of 150°C to a maximum of
260°C. In both cases the steam issuperheated.
Temperature generally tend to increase with time. The
maximum flow rate of a well is normally between 30 and 70
t/h. The maximum pressure registered in the boraciferous
region is estabilished in 60 Ata. Thermoelectrical utilizations, in Larderello may be distincted in at least three cycles, for cenvertion of natural steam energy, into electrical power. Structure and diaghrams of the cycles are shown in the respective graphics. |
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 Questo lavoro èstato realizzato con il contributo dei ragazzi del gruppo scientifico della 3B, 3D, 3F a.s. 1999/2000 |
