The annual increasing of load demand in electrical distribution networks leads to line congestion, decreasing the bus voltages below the acceptable limits and increasing the active and reactive power losses. However, renewable distributed generation (DG) has received increasing attention due to that growing in load demand. This paper presents a hybrid method based on moth-flame optimization (MFO) algorithm with loss sensitivity factor (LSF) to assign the optimal location and size of renewable DG units including solar (PV) and wind (WTG) based DG for minimizing the power losses taking into account the effect of annual load growth. The performance of this developed method is tested on IEEE 69-bus branch distribution system by comparing the results with other optimization techniques, the obtained results illustrate significant reduction in power loss, improvement in system voltage and increasing the distribution system capacity.