Abstract: A plant (10, 110) for the production of electric energy comprises a fuel boiler (11) in which a fluid is heated in order to produce steam, a turbine (15) which is connected to an electric generator (16) and to which said steam is conveyed, and a condenser unit (19) which re-condenses the fluid output from the turbine so that it may be conveyed back to the steam generator. The return fluid along the path from the condenser unit (19) to the boiler passes through a preheating unit (22) which receives heat from the turbine steam bleed-offs (23) and from a thermodynamic solar field (25). By making suitable use of the heat produced by the solar field (25) and contained in the heat-carrier fluid which passes through it, it is possible to increase the overall efficiency of the plant (10, 110).