A superconducting magnetic bearing (SMB) has been developed with high temperature superconducting (HTS) coils and bulks for a flywheel energy storage system (FESS). The FESS equipped with the SMB was tested at the mega photovoltaic power plant test site in Yamanashi Prefecture. The SMB with both rotor and stator made of superconducting material, was capable of supporting the flywheel weighing 4000 kg without any contact and has so far remained in stable operation for 5000 hours. A further increase in storage capacity is required for the FESS to be applicable to railways as a system for preventing cancellation of regenerative braking. This paper describes the development of a SMB capable of supporting large 147 kN loads using a new type coil structure for the improvement of FESS storage capacity.