Optimal Sizing of an Off-Grid Photovoltaic System for Sustainable Energy in Rabdhure District, Somalia

Abstract

Off-grid photovoltaic (PV) systems provide a sustainable solution for electrifying remote regions with limited access to the grid. This study presents the optimal sizing and performance evaluation of an off-grid PV battery generator hybrid system for the Rabdhure District, Somalia (3.95641° N, 43.12536° E). The initial system sizing was carried out using load-based calculations for a daily energy demand of 9.517 kWh, resulting in a configuration comprising a 14.4 kW PV array (36 modules), 32 batteries (6 V, 60 Ah), a 50A and 48 V MPPT charge controller, an 8 kW inverter, and a 33 kVA diesel generator. A detailed MATLAB Simulink model was developed to validate the system performance across four operating phases that represent different PV and generator availability scenarios. The simulation emphasizes a comparative analysis between a Perturb & Observe (P&O)-based control strategy and a conventional rule-based approach. The results show that P&O significantly enhances the maximum power point tracking (MPPT) form, stabilizes the PV voltage and power output, improves rectifier regulation, and ensures smoother battery charging with a linear increase in the state of charge. The SOC increased steadily from approximately 50% to above 52% during the simulation. Overall, the P&O-based system demonstrated superior stability, power quality, and energy utilization, confirming the importance of simulation optimization for the reliable operation of off-grid PV systems.