*2.1. Comparative Analysis of Conventional Method*

Investigating the appropriateness of different fuels and technologies, including renewable energy, is a practical decision-making practice for policymakers. Renewable energy sources can help to increase energy supply as well, to reduce emissions of greenhouse gas pollutants. Due to limitations of supplying the total energy from new sources of energy for now, finding an optimal combination of supply from both renewable and non-renewable energy sources is favorable. However, the rapid development and rising capacity of new technologies in different areas should be taken into account in planning future and targeting [39]. Ehsan and Yang [40] comprehensively investigated optimization methods employed in distributed generation in the power distribution networks. The Pros and cons of each method are shown in Table 1. The literature was investigated with a systematic review. Criteria for selecting articles included: publication dates between 1990 and 2020, use of a quantitative allocation technique, presence of a case study, use of optimization method, and those published in reputable journals.


**Table 1.** Comparative analysis of conventional techniques and metaheuristic algorithms [40].

Alternate energy sources cannot guarantee the continuity and reliability of the power supply. Vega-Garita et al. [41] and Calpa et al. [42] analyzed the effects of high PV penetration as the main source of energy for the Spanish electric grid. Renewable resources have many technical and economic benefits. Its technical benefits include reducing system losses, improved voltage, quality, high reliability, and economic benefits including low maintenance costs and fuel costs. The most common distribution generation (DG) systems today are residential solar technology, small wind turbines, and fuel cells. Some research work focusing on energy resource allocation optimization is listed in Table 2.


**Table 2.** Previous research in the field of energy resource allocation optimization.
