Abstract Superconducting magnetic energy storage (SMES) has been studied since the 1970s. It involves using large magnet(s) to store and then deliver energy. The amount of energy which can be stored is relatively low but the rate of delivery is high. This means that SMES is ideal for applications that require a high power for a relatively short period of time. SMES systems can be built with both low- and high-Tc materials. The systems which have been delivered so far have tended to be constructed from NbTi due to its low cost but as the new coated conductors are improved there is a strong possibility that systems based on YBCO have an attractive future.