An investigation of superconducting magnets for a 10 MWh SMES

Superconducting magnetic energy storage (SMES) systems are analyzed with respect to the potential impact of advancing materials technology. The effects of increased superconductor current density, magnet operating temperature and structural material strength are evaluated. For relatively low-field (<17-T) coils, NbTi and Nb/sub 3/Sn are used. For higher magnet fields and operating temperatures, the ceramic oxide BiSrCaCuO is anticipated in the near term (within 5-10 years). Advanced structural materials are also considered. These include cryogenic steels, maraging steels, and titanium alloys. Of these, Incoloy 908 (a cryogenic steel) is found to be the most suitable material for a small SMES system. The impact of fiber-reinforced steel composites is also evaluated. If all of the advances discussed become available (increased current density, operating temperature and allowed stress), the net conductor, structure and cryogenic cost of 10-MWh SMES systems may be reduced by over 45% relative to presently available technology.<>