The force on a flywheel increases with speed, and the energy a wheel can store is limited by the strength of the material from which it's made: spin a flywheel too fast and you'll eventually reach a point where the force is so great that it shatters the wheel into. The force on a flywheel increases with speed, and the energy a wheel can store is limited by the strength of the material from which it's made: spin a flywheel too fast and you'll eventually reach a point where the force is so great that it shatters the wheel into. Flywheel energy storage (FES) works by spinning a rotor (flywheel) and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the. Flywheel Energy Storage Systems (FESS) rely on a mechanical working principle: An electric motor is used to spin a rotor of high inertia up to 20,000-50,000 rpm. Electrical energy is thus converted to kinetic energy for storage. For discharging, the motor acts as a generator, braking the rotor to. If you take a flywheel with a heavy metal rim and replace it with a rim that's twice as heavy (double its moment of inertia), it will store twice as much energy when it spins at the same speed. It typically is used to stabilize to some degree power grids, to help them stay on the grid frequency, and to. Moreover,flywheel energy storage system array (FESA) is a potential and promising alternative to other forms of ESS in power system applications for improving power system efficiency,stability and security. The core technology is the rotor material, support bearing, and electromechanical control system.