OPTIMIZED HYBRID RENEWABLE ENERGY SYSTEM WITH PUMPED HYDRO STORAGE FOR RURAL ELECTRIFICATION IN NIGERIA USING ENERGY VALLEY OPTIMIZER

Abstract

Access to reliable and affordable electricity remains a major challenge for rural communities in Nigeria, where diesel-dependent generation results in high costs and environmental degradation. This study proposes an optimized standalone hybrid renewable energy system (HRES) comprising solar photovoltaic (PV), biogas generation, diesel generator (DG) backup, and pumped hydro storage (PHS) for the Ikere community in Oyo State, Nigeria. An Integrated Hybrid Energy Sizing Model (IHESM) was formulated as a weighted multi-objective optimization problem that simultaneously minimizes the levelized cost of energy (LCOE), loss of power supply probability (LPSP), and total energy/carbon cost (TCE). Weighting factors were selected to reflect equal priority to economic performance and reliability, with LPSP constrained to a maximum allowable reliability target of 0.101 (i.e., at least 89.9% supply adequacy), consistent with rural microgrid planning benchmarks. The optimization problem was solved using the Energy Valley Optimizer (EVO), a physics-inspired metaheuristic algorithm whose search mechanism mimics energy-state transitions in physical systems to enhance global exploration and convergence stability. Results show that the EVO-optimized configuration (900 kWp PV, 200 kW biogas, 200 kW×3 h PHS, and 550 kW DG) achieved an LCOE of ₦102/kWh while satisfying the imposed reliability constraint. Stability performance was evaluated in MATLAB/Simulink through Renewable Energy Fraction (REF) sweep simulations, demonstrating voltage regulation within 0.97–1.03 p.u. and fast frequency recovery (±0.12 Hz within 3 s) at approximately 85% renewable penetration. The proposed framework provides a cost-effective, reliability-aware, and operationally stable pathway for sustainable rural electrification in Nigeria.