It must be noticed that renewable energy resources operation with battery is the best method of electrical load cost provision. In this regard, integrated natural gas (NG) network with power system is utilized in this paper in order to increase system reliability and reduce pressure of power generators. In fact, NG is considered as clean and available fuel in order to support power system. It is possible to connect power system and gas network by Joint Unit (JU). JUs include Natural gas-fired distributed power generators (NGDG) and Power to Gas (PtG) units. In this paper, gas-fired turbine fuel supply process is prioritized. That is, desired gas is supplied by gas wells of gas network piping entry; PtG unit will supply NGDG gas as long as electricity cost is low. After optimal scheduling, By applying mixed integrated linear programming (MILP) for integrated system and two essential factors (power not supplied and gas not supplied), system operation under load and resources fluctuation studied. Finally, appropriate location and optimum capacity of new distributed energy resources for power system or compressor for gas network are selected. 24-Bus power system with renewable resources of Photovoltaic (PV) ،Wind Turbine (WT), battery energy storage, with 7- node natural gas network and two gas wells integration are selected as studied case for time range of 24 h in order to analyze process numerically.