Abstract
The growing global energy demand, particularly in large public infrastructures, necessitates a transition toward more sustainable and cost-effective energy solutions. This study investigates a large load profile of Makkah railway station to identify the optimal system that minimizes cost and environmental impact while maintaining energy reliability. Two hybrid renewable configurations are proposed: (1) Grid-connected Photovoltaic (PV/grid) and (2) PV/battery/grid. Hybrid Optimization of Multiple Energy Resources (HOMER) software was used to carry out the study. Simulation results reveal that the PV/grid system is the most effective configuration, achieving a Net Present Cost (NPC) of 27.9 million USD and a Levelized Cost of Energy (LCOE) of 0.0755 USD/kWh. This setup ensures 0% unmet load and delivers a renewable fraction of 26.7%, leading to a 26.72% reduction in Carbon dioxide emissions (CO₂ emissions) compared to the grid-only baseline. Its Internal Rate of Return (IRR) stood at 9.3%, confirming its strong financial sustainability. This makes it both a cost-effective and environmentally favorable choice. It is therefore recommended for high-load public facilities in solar-rich regions like Saudi Arabia, where integration of renewable energy is essential to achieving long-term sustainability targets under initiatives such as Vision 2030.