Research and development of HTS-SMES system

HTS-SMES has high potential to increase efficiency and future cost reduction. Therefore, MITI started new national project on feasibility study of HTS-SMES in FY 1999 for five-year project, as a sub-program of LTS-SMES cost reduction project, that is a succeeding project of 100 kWh SMES key technology development to FY 1998. In FY 1999, parameter survey has shown that 15 kWh class HTS-SMES can be realized by both of Bi-2212 and Bi-2223 wire operated at around 20 K with reasonable sizes by conduction cooling. As for Y-system wires, operating temperature around 77 K is rather high to have magnetic field to store enough energy. Lower temperature operation was suggested. Mechanical strength tests on Bi-2212 Rutherford cable revealed that they could withstand tensile strain up to 0.6% without I_c degradation. This allows high flexibility in mechanical design of HTS-SMES.