Geothermal exploration in Tuscany (Italy) for high temperature resources.

Larderello-Travale and Mt. Amiata fields are the Italian geothermal areas developed for electricity generation. Exploration and exploitation of geothermal resources initially involved a shallow reservoir made up of carbonatic-anhydritic formations, at a depth lower than 1000m, and temperatures of 150-250°C. Nowadays a considerable amount of fluid is withdrawn from a deeper metamorphic geothermal reservoir, at depths below 2500m, with temperature ws of 300-350°C. Geological, geophysical and thermometric data recently acquired indicate taht this deep reservoir covers an area much wider than the know and exploited gethermal fields, since tha thermal anomaly derives from large magmatic bodies inferred below 6-8 km depth. Shallow granitic intrusions (3.8-0.5 Ma) were indeed met in Larderello by deep wells at a depth of about 400m. At present, the most promising areas for geothermal exploration are located south of the Larderello-Travale filed and south-southwest of Mt. Amiata field. Deep exploratory boreholes are going to be drilled to verify the model reliability and to plan the exploitation. Any mid-low tempertaure geothermal resource at shallower depths will be developed together with the high-entalpy resource.