For a transformer, the annual energy loss depends on the load-dependent efficiency of the transformer and the characteristic load curve at the specific location in the grid or elsewhere. The goal of this work is the comparison of the efficiency and the annual energy losses of a superconducting (from 2G high temperature superconductors) and conventional transformer. The calculations of the load-dependent efficiency for both transformers are performed referring to a real case application of a power transformer in a power plant which defines the load curve of the device. For the conventional transformer the data base of an industrial product was used, whereas for the superconducting transformer a conceptional design for the selected specific application was developed and used for the calculations of the load-specific efficiencies and annual energy losses using the characteristic load curve of the selected application. The results show, that superconducting transformers made from high temperature superconductors (Coated Conductors), could have up to 80 percent less annual energy losses compared to the conventional transformer made from copper wires.