Large Flywheel Ready to Store Power at 1MW Solar Plant

2014/03/12 13:07
Kenji Kaneko, Nikkei BP CleanTech Institute
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The Railway Technical Research Institute (RTRI) and Furukawa Electric Co Ltd have developed a high-temperature superconducting magnet for large-size flywheels for the first time in the world.

They used the yttrium-based second-generation high-temperature superconducting wire manufactured by SuperPower Inc, which Furukawa acquired in 2012. The development was announced March 10, 2014. The newly-developed magnet is scheduled to be embedded in the large-capacity "superconducting flywheel power storage unit" and linked to a 1MW solar power plant to be built in Komekurayama, Kofu City, Yamanashi Prefecture, Japan, in 2015 on a trial basis.

The "flywheel power storage system" stores electricity by using surplus electricity of a mega-solar (large-scale solar) power plant, etc to rotate a large-size disk (flywheel) inside the system. When the amount of power generated decreases due to cloudiness, the system generates electricity to make up for the decrease. It can be used as a "battery" and has already been employed for effectively using electricity (regeneration invalidation prevention) for railway systems.

For the next-generation flywheel power storage system being developed, a superconducting magnetic bearing that RTRI developed by combining a superconducting bulk body and superconducting magnet was employed. Operating efficiency is improved by contactlessly floating the rotating disk to lower the friction loss of the bearing to zero.

Also, the product life of the bearing, which generally needs to be replaced on a regular basis, becomes semipermanent. The superconducting magnetic bearing being developed is aimed at floating an about 4t disk with a pair of bearings.

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