A novel penalty function for the trade-off between cost and reliability optimization of standalone solar PV/battery system

Most of the research done on sizing off-grid solar PV/battery systems are based on advanced optimization algorithms, which are difficult to implement in practice. Moreover, adequate attention has not been paid to the key compromise between oversizing and under-sizing batteries. Oversized batteries incur unnecessary costs while undersized systems defy reliability. This study offers a simple yet effective penalty function-based approach to determine the optimal size of the battery with equal consideration to cost and reliability. This approach penalizes the size of battery storage in decision-making and incorporates such reasoning into a mathematical formulation to provide a simpler solution for practical systems. Lithium Iron Phosphate (LiFePO 4 ) batteries were analyzed due to their high energy density, long cycle life, and safety. A detailed examination of the system load profiles, and solar irradiance was utilized to validate the model. This research presents a new and effective approach to simplify the optimization of battery sizing using real-world methods, a gap which has been left by previous literature. This technique allows for efficient and economical use of battery storage in standalone solar PV systems, particularly in resource-constrained regions where the reliability of the system is critical.