Size Optimization and Sensitivity Analysis of HRES of a Rural Off-Grid School in Bangladesh

Hybrid renewable energy system (HRES) is an emerging concept that assists in enhancing the supply of electricity with negligible release of pollutants like carbon dioxide and thus contributing towards SDG-7 (Affordable and Clean Energy) and SDG-13 (Climate Action). However, natural resources are uncontrollable and inadequate electricity generation from renewable sources may fail to match peak demand all the time. To this end, we propose a photovoltaic (PV), battery based HRES with conventional generator as a backup system for improving the low efficiency and inconsistency of renewable energy by determining the optimal HRES size focusing on cost of energy (COE), net present cost (NPC), and greenhouse gas emissions. The HRES has been designed according to the load profile of a rural off-grid school in Bangladesh named “73 No. Char Alatuli Kodalkati Government Primary School”. PV only system is present near the area but with low reliability and low robustness. After thorough energy balance calculation, the optimization of equipment size for all feasible configurations is conducted in HOMER. Additionally, sensitivity analysis has been performed to determine the sensitivity of the cost of energy to the variables load, fuel cost and interest rate. The results corroborate that, optimized HRES utilization reduces the cost of energy and greenhouse gas emissions by 90.88% and 95.54% respectively than generator only system though installation of conventional on-grid system is expected to make the energy cheaper with higher carbon pollution. Thus, the optimized HRES enhances stability with least cost of energy and net present cost (NPC). This study will ease the prospective large-scale PV and battery based HRES design to secure higher stability and with the smallest plausible size and cost of energy.