Which, using a heat transfer fluid in any thermodynamic cycle or system for using process heat, comprises: two-dimensional solar concentrator means for heating the heat transfer fluid from a temperature T1 to a temperature T2; three-dimensional solar concentrator means for overheating the heat transfer fluid from a temperature T2 to a temperature T3; such that the advantages of working at high-temperatures of the three-dimensional solar concentrator means are taken advantage of with overall costs similar to those of two-dimensional solar concentrator means. In a specific application for generating electric power, the two-dimensional solar concentrator means consist of a parabolic trough collector (1), while the three-dimensional solar concentrator means consist of a heliostat field and central tower (2) for generating overheated steam that expands in a turbine (6) coupled to an electric generator (7).