At its core, a flywheel energy storage system stores energy in the form of rotational kinetic energy. The system consists of a large rotating mass, or rotor, that spins inside a vacuum-sealed container. 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. Kinetic energy can be described as “energy of motion,” in this case the motion of a spinning mass, called a rotor. This innovative approach harnesses kinetic energy to create a robust storage solution that addresses some major challenges faced by. .
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