Exploitation of geothermal energy in active volcanic areas: A numerical modelling applied to high temperature Mofete geothermal field, at Campi Flegrei caldera (Southern Italy)

Abstract

The active volcanic area of Campi Flegrei represents one of the “hottest” sites of worldwide continental areas. Exploitation for geothermal energy of this volcano is of great interest, because temperatures>150 C occur at very shallow depth (0.5e1 km). Since present time, the exploitation of geothermal energy in Italy, for electric uses, has been confined to the Larderello and Mt. Amiata districts (Tuscany). With the recent introduction of new Italian regulations, which favor and incentivize inno- vative pilot power plants (5 MWe), many geothermal projects have been applied to volcanic districts of Southern Italy, providing a new important input to the development of zero-emission geothermal power plants. In this framework, we analyzed the sustainability of geothermal exploitation in the high tem- perature geothermal field of Mofete (Campi Flegrei caldera) in Southern Italy. By a review of all the available data of drillings performed at Mofete, from 1979 to 1987 by AGIP and ENEL companies, and using a numerical simulation (TOUGH2®), we evaluate the thermal and pressure perturbation of the reservoirs, and the possible induced seismicity, due to extraction and reinjection of fluids, at different depths and temperatures. The results are fundamental in planning a sustainable geothermal energy production in urbanized and high volcanic risk areas.