This thesis has given an introduction to the background of the development of superconducting materials and their physical theory. It has also outlined SMES technology, including its history and the current status of research. A complete optimisation algorithm was presented. This algorithm can calculate the design to achieve the maximum stored energy in a SMES system using the finite length of conductor available. This algorithm can be of assistance in the design of other SMES projects. A new numerical model was investigated to predict the electromagnetic behaviour of a 2 G HTS pancake coil. This model is easy to compute without reducing its complexity in terms of the physical theory underlying the coil’s properties. Important parameters such as the critical current and AC loss can be calculated by this model. More importantly, this model is also applicable to other 2 G HTS pancake coils. This will help the study of other devices, such as superconducting machines, transformers and fault current limiters.