| Abstract |
The Adriatic Area shows one of the best climatic and geological conditions for fully exploit the potentialities of low temperature geothermal energy with Ground-Source Heat Pumps (GSHP) due to the presence of medium temperature sedimentary basin across the Western Adriatic shore and the shallow geothermal conditions which characterize the entire Eastern Adriatic Countries. Participating regions in the LEGEND project (IPA Adriatic programme) made benchmarking reports to be able to exchange experiences of shallow geothermal energy potential and to overcome barriers for faster development of GSHP for heating and cooling in the Adriatic region. The whole Adriatic territory has very diverse geological and hydrogeological characteristics. The Southern Alps, the External Dinarides and the Apennines are mostly represented by carbonate rocks, the latter also by marl and sandstone (flysch rocks). Alluvial sediments (conglomerate, gravel, sand, silt, clay) are found along the narrow riverbeds and in wider groundwater basins, i.e. Po valley alluvial fan deposits (Italy). Thermal conductivity and volumetric heat capacity values are quite similar for the same rock types everywhere in the Adriatic region, in dry and wet conditions, typically in range 2.4 to 3.0 W/(m•K) and 2.3 MJ/(m3K) respectively for limestones, 2.4 W/(m•K) and 2.2 MJ/(m3K) for flysch rocks, or, for example, important for alluvial deposits as clay with 1.6 W/(m•K) and 2.4 MJ/(m3K), and as gravel including sand and silt with 2.1 W/(m•K) and 2.4 MJ/(m3K). Temperatures, geothermal gradients and heat flow density (HFD) are mostly below world mean values for continents, geothermal gradient in the karstic areas of SW Slovenia and in Istria is in a range 10 to 25 mK/m, similar in Montenegro (Podgorica region) with up to 30 mK/m and HFD of 20 to 50 mW/m2. There are limited areas of elevated values, as geothermal gradient up to 45 mK/m in the upper 500 m of Slovenian coastal area with also HFD slightly elevated as regard to world mean value for continents (65 mW/m2). Average and elevated values are found also in Province of Ferrara with gradients from 20 to 65 mK/m. |