This paper presents the approach of fuzzy numbers for reliability calculation of electrical energy indices and compared to an analytical method. In this paper, the fuzzy numbers which are represented by triangular fuzzy numbers are used to evaluate the load duration curve and the probabilities capacity generators that are in services, in term of the expected energy not supplied (EENS), loss of energy expectation (LOEE) and the energy index of the reliability (EIR). A case study based on the Malaysia distribution network (DISCO-Net) is carried out.The proposed method shows a simple implementation andthe results seem to be a good approximation to the analytical approach.