Methods for the estimation of the energy stored in geothermal reservoirs

The paper analyze the problem of the estimation of the potential of geothermal reservoirs with the objective of sizing of geothermal power plants in order to reach the goal of a correct matching of renewability and economic related issues. After an analysis of the typical approaches based on the First Order Method diffused in the literature since the late 70s and of the uncertainties connected with the use of simplified approaches, that have determined general overestimation of the geothermal energy stored in the reservoirs and of the size of the plants connected to various geothermal fields, the authors discuss about possible improvements based on the combination of theoretical simplified approaches with experimental data of heat flow, taking into account not only the energy stored, but also the possibility of producing a recharge.