Superconducting magnetic energy storage (SMES) systems

Superconducting magnetic energy storage (SMES) is one of the few direct electric energy storage systems. Its specific energy is limited by mechanical considerations to a moderate value (10 kJ/kg), but its specific power density can be high, with excellent energy transfer efficiency. This makes SMES promising for high-power and short-time applications. So far SMES uses Nb-Ti conductors, due to their low cost. Apart from the cost, YBCO appears very attractive due to its current capacity, mechanical performance and 'high' operating temperature. Since the first studies in the 1970s, successful demonstrations of SMES have been carried out but the high cost has prevented commercialization.