| Title | Geothermal potential areas in Southern Italy: new exploration and exploitation perspectives. |
|---|---|
| Authors | Buttinelli, Procesi, Pignone, Quattrocchi |
| Year | 2013 |
| Conference | European Geothermal Conference |
| Keywords | Spatial Analysis, Geographic Information Systems, Weighted Overlay, Geothermal Resources, Southern Italy |
| Abstract | Spatial analyses performed under GIS environments represent a powerful tool for environmental resources evaluations, to produce continuous thematic mapping of the territory as a function of interplaying factors. The Purpose of this study was to establish spatial relationships among different kind of geological data throughout weighted overlay functions, in order to identify and map the Italian geothermal resource, focusing on its southern regions. The approach to this challenging task was based on the differentiation of two main types of data which drive the research of a potentially exploitable geothermal resource: i) predisposing factors which basically allow the identification of a deep source of energy (namely an easy recoverable hot fluid); ii) limiting factors for its feasible exploitation, which essentially consist in geological hazards factors (mostly seismicity and seismogeneicity). Data have been organized into a dedicated geo-database, including vector and raster information as: surface geology; principal faults databases (shallow and deep, active or not); seismogenetic sources and areas; gravimetric anomalies; stress maps and stress field regime analysis; underground information (wells and seismic profiles available from hydrocarbons and geothermal explorations); caprock and deep aquifers distribution; underground temperatures; heat flux; depths of potential reservoirs suitable to geothermal exploitation; recorded seismicity (INGV catalogues since 1981); historical seismicity; Italian seismic zonation; seismic hazard maps; volcanic hazard maps; principal diffuse degassing structures (DDS). A series of transformations were performed in order to homogenize the layers information and to make the spatial correlation possible (mostly raster conversions and reclassifications). Biased weights were assigned to each reclassified layer value. Weighted Overlay operations were then conducted via the ArcGIS model builder tool, taking into account such weights and the overall influence of each layer. Two basic overlays of geo-predisposing factors and geo-hazards have been obtained. A final overlay between them was performed in order to produce the spatial distribution of the “reliably exploitable” geothermal macro-areas, which often correspond to the main geothermal manifestations already known. These also confirm the capability of this approach, which might be used to research new areas not clearly identifiable with the current datasets and classical approaches. However, in such new areas more detailed “site-specific” studies should be performed to evaluate the geothermal potential in terms of thermal, electric power and energy supply. This multidisciplinary approach would be proposed as a standard for the geothermal research evaluation and also extended to such researches aimed at the development of strategic energy mix plans in which different underground uses (CO2 and CH4 storage) can be combined with geothermal exploitation to solve the problem of the increasing energy demand. |