Cost allocation of losses in power networks is an essential issue especially under modern electricity markets with high penetration of renewable energy sources (PES). This paper proposes the application of an efficient loss allocation method developed to evaluate the marginal loss coefficients of dispersed generation. The coefficients provide the contribution to the active and reactive losses of each producer/consumer in order to define the respective tariffs. One innovative feature of the proposed loss allocation method is that, unlike other proposed approaches, it is irrespective of the reference bus selection and takes in consideration the impact of reactive flows on active power losses. Crete's power system has been considered as a representative study case for the demonstration of the presented method.