Geothermal Potential: a New Assessment Approach and its Application to VIGOR Regions

Geothermal assessment and the mapping of suitability for different geothermal uses are of strategic importance for successful policy strategies regarding geothermal exploitation. The VIGOR project falls in this context, since one of its main targets is the geothermal potential assessment both at local and regional scale, distinguishing the latter as regional shallow and regional deep settings. In collaboration with TNO (Netherlands Geological Survey), a methodology has been optimized for the geothermal potential resource assessment for the VIGOR Project region. The regional deep geothermal potential evaluation has the main purpose to assess the resource below 500 m depth, therefore to identify and locate the reservoir, estimate the amount of heat in place and eventually the energy produced on the base of the resource and the application to be developed (e.g., power production by binary plant, type of direct use). The procedure for the VIGOR project is called VigorThermoGIS, which is an implementation of the ThermoGIS TNO code, and is based on a three dimensional model discretized into a regular grid spaced by a lateral 1000 m and by 100 m in depth. For each cell the Heat In Place and Technical Potential are calculated, then the grid maps representing the suitable place for a specific kind of application are extracted. The VIGOR ThermoGIS code is written in Java, which can be executed on any machine. The required input data are: the reservoir thickness, the thermal model for the considered volume, the permeability values of the reservoir, and also a set of parameters such as the water density, rock reservoir density, heat capacity of the formation water and reservoir rocks and the surface average annual air temperature. VigorThermoGIS output maps allow to quickly assess key parameters such as depth, thickness, temperature, flow properties, and to evaluate the performance assessment at any location, defining suitability for geothermal power and/or heat production. The obtained output maps will be available into the VIGOR Project webGIS platform in a short time. In figure 1 is shown, as an example, the preliminary technical potential map for the suitability of power production by Binary technology in Sicily . Although the geothermal resources assessment at regional scale for the VIGOR Project is still in progress, the preliminary results allows to go towards the next step regarding the economics aspects, i.e., to evaluate the levelized cost of energy (LCOE) for a specific exploiting project.