Efficient planning of renewable energy-based Distributed Generation units (RE-DGs) adapted in distribution networks brings about numerous advantages, with significant technical and economic implications that greatly influence the whole system quality and performance. However, achieving optimum apportionment and optimal sizing of RE-DGs, especially photovoltaic equipment (PV), remains challenging due to the unpredictable nature of renewable resources. In this paper, a novel methodology is proposed to address the problem of optimization in planning RES-DGs. This methodology is based on the Strength Pareto Evolutionary Algorithm 2 (SPEA2). The efficiency of the approach is demonstrated through a test of validation on the IEEE 33-bus distribution system. The represented results highlight that optimizing the allocation of PV systems, considering their stochastic behavior and the time-varying load model, positively impacts the network by reducing power losses and minimizing voltage deviation.