Summary: Discover how flywheel energy storage systems work, their maintenance best practices, and why industries like renewable energy and transportation rely on them. Learn about real-world applications and cost-saving strategies. 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 system is an energy storage device that converts mechanical energy into electrical energy, breaking through the limitations of chemical batteries and achieving energy. Back-to-back plus DC-AC converter connected in DC-link. Source: Adapted from [27, 300]. Can flywheels be used for power. .