Abstract
Superconducting flywheels store energy in a rotating wheel that is supported by superconducting magnetic bearings. The superconducting magnetic bearing (SMB) consists of a bulk superconductor stator and a permanent magnet rotor. The rotor is levitated by the pinning force of the bulk superconductor. The SMB has lower rotational loss than conventional mechanical bearings and is suitable for long-term energy storage such as the diurnal load leveling of electric power. Research and development of a 10kWh system and a 100kWh SMB module using radial-type SMBs are being conducted by ISTEC, Shikoku Research Institute Inc., Ishikawajima-Harima Heavy Industries Co., Imra Material R & D Co., Sumitomo Special Metals Co. and Koyo Seiko Co. as a NEDO project. As a long-term goal, the NEDO project aims to develop a 10MWh power storage system to level diurnal power load. The group of Chubu Electric Power Co. and Mitsubishi Heavy Industries fabricated a thrust-type SMB of 620mm in diameter. Argonne National Laboratory tested a 2.25kWh system using a hybrid bearing consisting of SMBs and permanent magnet bearings. A 10kWh system was studied by Boeing Co. as a SPI (Superconductivity Partnership Initiatives) project in the USA.
