Nowadays, the energy storage is a fundamental aspect and there exists so many ways to do it. One of these ways, is the energy storage associated to rotational kinetic energy, better known like Flywheel Energy Storage (FES). FES is a complex system formed by different subsystems, and the most important of these subsystems is the rotor because it´s the element that enabled performs the function of storing energy. Rotor’s can be classified into two types: the rotors made with metal and the rotors made with composites. This article exposes a comparison between different settings of rotors to demonstrate the advantage of the use of composites comparing with the use of metals, especially in terms of energy density.
Key Words: Rotor; Flywheel Energy Storage; Stress; Composites