Therefore, load curtailment and integration of energy storage systems has been exploited to decrease power fluctuations and overcome any system constraint violations [1]. Nowadays, the integration of DG into distribution systems considering the energy losses has enticed attention. Research on the allocation of renewable DG (e.g., solar, wind and biomass) has been proposed to reduce energy loss, considering the variations of power generation and load demand [11; 14; 15]. According to the presence load type characteristics, optimum DG power factor dispatch for every load level would be an integral part for reducing energy losses. Nevertheless, most of the current research assumed that the DG systems work at predefined power factors. In contrast to generation systems that depend on conventional generation techniques such as gas turbines and reciprocating engines, PV energy resources are non-dispatchable and intermittent, depending on temperature and radiation. The BESS technologies create a chance to transform the PV energy resources from non-dispatchable systems to dispatchable systems with similar conventional resources [20; 21]. Throughout the past two decades, a hybrid system of BESS and PV has been considered for the applications of stand-alone systems [22; 23; 24]. Recently, the hybrid system of PV and BESS has been exploited as one of the furthermost worthwhile solutions in grid-connected applications to increase the penetration of the PV energy system in distribution systems. Such hybrid design helps alleviate the influences of intermittency in the PV energy systems, and offers many benefits for the owners of PV system, customers, and utilities. Many researchers have devoted their efforts to this interesting topic [18; 19; 20; 25; 26; 27; 28; 29; 30; 31]. A hybrid PV-BESS has been evolved for applications of load demand-side to improve the efficiency of the electrical system [25; 26]. In [27], authors have proposed an optimal BESS charging and discharging schedule in a PV grid-connected system for shaving of peak demand. Authors in [28] have presented a methodology to calculate the BESS size for shaving of peak load and power balance used in case of connecting PV energy system with the grid. In [29], authors have presented a methodology to compute the BESS size for raising the penetration of the PV energy system in case of residential system load with the objectives of voltage regulation and decreasing in maximum output power and yearly cost. A discharging and charging strategy for the BESS has been suggested to alleviate abrupt changes in the output power of the PV energy system and boost the evening peak load in the case of a residential load system [30]. The authors in [18] have proposed a conception of voltage regulation voltages in the distribution systems with high penetration of PV energy system by adjusting the output power of BESS at customer-side. BESS has been controlled and sized to diminish the fluctuation in the PV output power [20; 31]. In [19], the authors have evolved the BESS's best discharging and charging schedule on an hourly basis to alleviate the discontinuity of PV output by reducing the energy loss. Generally, the previous review indicates that significant research has been published on the size and discharging and discharging schedules of the BESS exploited in the case of connecting the PV energy system with the grid. Nevertheless, most of the research introduced has supposed that the optimal power factor dispatch for every hybrid PV-BESS throughout all of the time intervals is ignored as well and the size of PV units exploited in hybrid PV-BESS is prespecified. Based on the characteristics of the loads served, every PV-BESS hybrid that can provide reactive and active power with the optimum power factor may positively reduce energy losses in distribution systems. This paper shows a conception of involving a hybrid PV and BESS in residential, industrial, and commercial distribution systems, taking into account the system energy loss.