Characteristics of Compensation for Fluctuating Output Power of a Solar Power Generator in a Hybrid Energy Storage System Using a Bi2223 SMES Coil Cooled by Thermosiphon with Liquid Hydrogen

Due to global issue of energy shortage, alternative energy such as solar and wind energy has to be introduced to the commercial electricity grid. A hybrid energy storage system which is able to convert unstable alternative energy into constant electricity has been proposed. The hybrid energy storage system is composed of hydrogen system and SMES system. This research concerns on the issue of continuous operation of SMES system by introducing a threshold voltage range into the SMES control method. This control method was applied to an SMES coil in a 1-kW-class hybrid energy storage model system. Using the control method, we could restrain the temperature rise of the SMES coil. An experiment has been carried out to confirm the effectiveness of the control method in continuous operation of the hybrid energy storage system. The fluctuation output of a solar power generator was appropriately compensated by electrolyzer and SMES systems.