A floating drum turbine is used for generating the electrical energy from the kinetic energy of a water stream (sea wave or river flow) that provides the mechanical energy needed to rotate an electrical generator for generating the electricity. The drum turbine is installed on a buoyant skid anchored to the seabed by some chains/ropes to keep it in a fixed position and direction along the water stream. The turbine is coupled to an electrical generator with a power transmission system, and generates the electricity that is transferred to the coast using a cable system floated on the water surface.