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 megawatt photovoltaic power plant test site in Yamanashi Prefecture. Both the rotor and stator of the SMB are made of superconducting material, and are capable of supporting a flywheel weighing 4000 kg without any contact. So far, the system has remained in stable operation for 5000 hr. 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. A SMB capable of supporting large 147 kN loads using a new type of REBCO tape has been developed and produced by SuperPower Inc. This paper describes the development of SMBs with loads 39.7 kN and 147 kN, and the development of REBCO wires.