Techno-economic evaluation of PV–vanadium redox flow battery systems for peak shaving in football stadiums under time-of-use tariffs

This study presents a techno-economic evaluation of a grid-connected photovoltaic (PV) and vanadium redox flow battery (VRFB) system for peak shaving in a football stadium under time-of-use (TOU) tariffs with demand charges. Suphachalasai National Stadium in Thailand is used as a case study to investigate three operational strategies: (i) PV-only charging, (ii) grid-based off-peak charging, and (iii) hybrid PV–grid charging. Due to the temporal mismatch between daytime PV generation and evening stadium operation, a VRFB system is employed to enable energy shifting, peak shaving, and electricity cost reduction. A simulation framework is applied to evaluate load coverage, battery utilization, peak demand reduction, energy cost savings, and economic performance under the three operating strategies. Among the evaluated strategies, the grid-charging strategy achieves the highest battery utilization (82.5%) and annual battery throughput, while the hybrid PV–grid charging strategy provides the greatest operational flexibility by combining PV utilization, off-peak grid charging, and peak shaving. Demand charge reduction was identified as the dominant contributor to annual cost savings, exceeding the benefits obtained from PV self-consumption and energy arbitrage alone. Although the proposed system significantly reduces electricity expenses, the economic feasibility strongly depends on annual operational utilization. The analysis indicates that increasing utilization toward approximately 300–325 operational days per year could substantially improve the economic attractiveness of the system and bring the simple payback period closer to the 25-year project lifetime. The findings highlight the importance of integrated energy management and value stacking strategies for commercial facilities with intermittent load profiles. The proposed approach provides practical insights into the deployment of PV–VRFB systems in stadiums and other large-scale facilities operating under TOU tariff structures with high demand charges.