| Abstract |
Italian geothermal resources potentially harnessable on land within 5 km depth are ~ 21 EJ; but 30% max. of them have a sufficiently high temperature enabling economic power production. The rest (more than 70%, at T< 90 °C) are suited for direct uses only. Concerning high temperature fraction, maybe 20% of the max. 30% said above are associated with hydrothermal systems, whereas the other 80% are tied to unconventional geothermal systems: HDR/EGS, supercritical fluids, pressurized systems, magmatic systems, and hot brines. This means that a small fraction only of the Italian high-temperature geothermal potential is economically harnessable at present costs. To assess what reasonable future could geothermal energy have in Italy, based on a thorough analysis of the geological and reservoir situation of all Italian geothermal resources, and on the expected technological-economic conditions related to their exploitation, starting from the situation at Dec. 2010, a study has been carried out by UGI on their possible development up to 2030. Projections have been made according to two different growth scenarios, a prudent one (Scenario I) and an ambitious one (Scenario II), with 5-by-5 year steps to make periodical checks. All types of systems (the hydrothermal ones and the above-said unconventional geothermal systems) have been considered for possible exploitation down to 5 km depth till 2030. For the unconventional systems, however, we have hypothesized that their technological and economic viability cannot be reached in Italy before the beginning of the next decade. The main results of the study in question are summarized in this paper, including: i) geothermal potential to 5 km depth; ii) role of the Earth’s heat in the national energy framework as of Dec. 2010; iii) geothermal development 2010-2030 and expected share in the framework of the total energy consumption supposed to occur in Italy by 2030; iv) technical, socio-economic, environmental, and scientific benefits expected from the development of geothermal energy; and v) measures required to achieving the targets envisaged. With reference to the situation at Dec. 2010 (882.5 MWe with 5.34 TWh/y for power generation, and 1000 MWt with 12,600 TJ/y for direct uses), the forecasts at Dec. 2030 of geothermal development in Italy for the two growth scenarios said above are as follows: Scenario I: 1500 MWe with 9.4 TWh/y for power generation, and 7400 MWt with 65,200 TJ/y for direct uses; Scenario II: 2000 MWe with 12 TWh/y for power generation, and 8800 MWt with 90,000 TJ/y for direct uses. From the figures above one can calculate that the total geothermal development in 2030 would increase by 2.5 and 3.4 times approx. (for Scenarios I and II, respectively) as compared to the situation at Dec. 2010. These values would represent 1.5÷2% of the total energy consumption guessed to occur in Italy in 2030, and CO2 avoided emissions of between 10 and 13 million tonnes/year, approx. |