This article focuses primarily on modeling, simulation, performance and financial analysis of connecting 50 MW commercial photovoltaic (PV) energy system to the microgrid distribution system in eastern region of Saudi Arabia. The PV energy system generation will enhance the dependability, load demand and the cost-effective procedure for the microgrid distribution system amid mostly classic fossil fuel-based power plant. PV array is designed assuming that it will be installed next to the Qurayyah power plant in aforementioned region to help nearby cities to become smart cities in the future. In addition, this research will help to establish a clear plan of how a change of dependability on fossil fuel power plant to renewable power plant may take place. PV power plant will reduce the amount of fossil fuel used, CO2 emission and cost of kilo-watt per hour (kWh) in the future since demand is increasing every year. Hence, the PV power plant will support the cities' power need especially during the peak demand. The procedure of designing grid-connected photovoltaic (PV) system contains of selecting main and balance of the system (BOS) components e.g. PV module , and inverter within suitable specification as well as weather related aspects to confirm the maximum production, reliability, sustainability, and reduce the cost. Open source computer-based modeling and simulation tools, e.g. system advisory model (SAM) and Pvwatts were used to model and modify the system. System performance and financial analysis were carried out for the different system configuration for optimization. The results demonstrated that within a short period of time the system will cover the installation cost with a substantial disbursement through the lifetime of the system, even though the initial cost is significant.