NOVELTY - The system has a flexible slim element (1) e.g. cable, that is adapted to be placed in a fluid flow e.g. marine current. The slim element is ready to vibrate under the action of the fluid flow, where the vibration induces a deformation and/or a displacement of the flexible slim element. An electric converter (4) e.g. magnetostrictive electric generator, is arranged for transforming the deformation and/or displacement of the flexible slim element into electric power. The slim element is provided in a tensed manner.    USE - System for recuperation of energy of a fluid flow for producing electrical energy. Uses include but are not limited to marine current, oceanic current, river current and wind current.    ADVANTAGE - The electric converter is arranged for transforming the deformation and/or displacement of the flexible slim element into electric power, thus allowing the energy recuperation system to be simple without requiring a preliminary transformation of energy into mechanical energy, and limiting energy losses. The slim element is of low costs and has immunity in the marine center. The system provides increased electric power, and has minimized hydrodynamic interferences. The system has no losses due to portable units. The parts of the converter are static, compact and robust to resist maritime environment. The system has reduced maintenance interventions, and the direct conversion of energy generated by the cable does not require intermediate transformations such as hydraulics, that cause energy loss.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) an energy recuperation assembly    (2) a method for recuperation of energy of a fluid flow.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic side view of a system for recuperation of energy of a fluid flow in which a flexible slim element is vertical.    Flexible slim element (1)    Float (2)    Sea-bed (3)    Electric converter (4)    Anchoring unit (5)