Technologies for energy storage. Flywheels and super conducting magnetic energy storage

The author examines both flywheel and superconducting magnetic energy storage technologies. A flywheel is an electromechanical storage system in which energy is stored in the kinetic energy of a rotating mass. Flywheel systems under development include those with steel flywheel rotors and resin/glass or resin/carbon-fiber composite rotors. The mechanics of energy storage in a flywheel system are common to both steel- and composite-rotor flywheels. Superconducting magnetic energy storage (SMES) is an energy storage device that stores electrical energy in a magnet field without conversion to chemical or mechanical forms. In SMES, a coil of superconducting wire allows a direct electrical current to flow through it with virtually no loss. This current creates the magnetic field that stores the energy. On discharge, switches tap the circulating current and release it to serve a load.