The legal diploma concerning the legal regime of the disclosure and exploitation of geological resources (Law n.º 54/2015, of 22 June) in particular paragraph o) of article 2º, states that geothermal resources are "the fluids and geological formations of the subsoil, whose temperature is susceptible to economic exploitation”.

A complex and diverse geology has endowed the country with a considerable geothermal potential, evidenced by the high number of occurrences of water with temperatures above 20°C.

DGEG has carried out an exhaustive study of the occurrences of water with temperatures above 20°C, both natural springs and from water wells, through the compilation of information and technical data dispersed in the processes of the concessions and the reports filed at DGEG, and also the geological-structural characterization of the occurrences.

From the surveys carried out by DGEG, it appears that the vast majority of thermal occurrences have relatively low temperatures, but could be high when subjected to prospection and research work in depth. In recent years it has been observed that the increase in drilling depth is almost invariably accompanied by a corresponding increase in the temperature of the fluids captured, which opens up new prospects for the prospection and exploration of geothermal resources in mainland Portugal.

Competences of the Directorate of Services of Hydrogeological and Geothermal Resources (DSRHG)