A hybridization system for use in a hybrid energy plant (35, 50, 60, 70) that comprises a first thermal energy unit powered by a solar field for providing thermal energy to a user via a first heat transfer fluid and a second non-solar thermal energy unit providing thermal energy to said user via a second heat transfer fluid, said hybridization system comprising: a thermal energy storage unit and mixing unit coupled directly or indirectly to the first thermal energy unit and to the second thermal energy unit for receiving, storing and mixing thermal energy from the first thermal energy unit and the second thermal energy unit so as to form either directly or indirectly a unified heat transfer fluid that is fed to the user, wherein the thermal energy storage unit comprises a first tank to store hot fluid as a medium to store the thermal energy and a second tank to store said fluid in its cold condition, and wherein the mixing unit is configured to mix thermal energy derived from the hot fluid with thermal energy derived from the HTF of the solar field; characterized in that: the mixing unit includes a control unit configured to use data from the solar field including actual and forecast weather data to adjust operation parameters of the solar field, the second non-solar thermal energy system and the TES, and to use data from the TES to adjust operation parameters of the second non-solar thermal energy system, and the second non-solar thermal energy unit includes a heater that directly heats the fluid or provides thermal energy to the TES, in parallel with the thermal energy derived from the HTF of the solar field so as to both feed energy to the TES at a common input thereof and to receive the returned colder fluid from the user via a common output thereof. a thermal energy storage unit and mixing unit coupled directly or indirectly to the first thermal energy unit and to the second thermal energy unit for receiving, storing and mixing thermal energy from the first thermal energy unit and the second thermal energy unit so as to form either directly or indirectly a unified heat transfer fluid that is fed to the user, wherein the thermal energy storage unit comprises a first tank to store hot fluid as a medium to store the thermal energy and a second tank to store said fluid in its cold condition, and wherein the mixing unit is configured to mix thermal energy derived from the hot fluid with thermal energy derived from the HTF of the solar field; characterized in that: the mixing unit includes a control unit configured to use data from the solar field including actual and forecast weather data to adjust operation parameters of the solar field, the second non-solar thermal energy system and the TES, and to use data from the TES to adjust operation parameters of the second non-solar thermal energy system, and the second non-solar thermal energy unit includes a heater that directly heats the fluid or provides thermal energy to the TES, in parallel with the thermal energy derived from the HTF of the solar field so as to both feed energy to the TES at a common input thereof and to receive the returned colder fluid from the user via a common output thereof. the mixing unit includes a control unit configured to use data from the solar field including actual and forecast weather data to adjust operation parameters of the solar field, the second non-solar thermal energy system and the TES, and to use data from the TES to adjust operation parameters of the second non-solar thermal energy system, and the second non-solar thermal energy unit includes a heater that directly heats the fluid or provides thermal energy to the TES, in parallel with the thermal energy derived from the HTF of the solar field so as to both feed energy to the TES at a common input thereof and to receive the returned colder fluid from the user via a common output thereof.