Flywheels store energy in the form of rotational energy. 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. The California Energy Commission's Energy Research and Development Division supports energy research and development programs to spur innovation in energy efficiency, renewable energy and advanced clean generation, energy-related environmental protection, energy transmission and distribution and. 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 | A DIY demonstrator of flywheel energy storage, including detailed descriptions of mechanics, electronics and firmware. com/a-sc/Flywheel for design files and firmware source. A rotating mass, ideally spinning in a vacuum. While the technology has been around for decades as a form of Uninterrupted Power Supply (UPS) to provide power when.