Evaluation and optimization of off-grid and on-grid photovoltaic power system for typical household electrification

This study aims to design a renewable energy system that can meet the desired electrical load of households with low energy cost, high renewable energy fraction and low CO2 emissions. Photovoltaic solar power systems used to electrify typical households in Iraq were investigated through simulation and optimisation. One-minute resolution simulations and optimisations were performed to determine the performance and net present cost of two photovoltaic power system configurations, namely (i) off-grid and (ii) on-grid solar photovoltaic power systems. Results show that the two systems exhibit excellent performance, but the on-grid photovoltaic power system requires cheaper cost compared with the off-grid photovoltaic power system. The total energy generated from the off-grid photovoltaic power system meets the desired electrical load of households and recharges the batteries, whereas the excess electricity from the on-grid photovoltaic power system feeds the grid. The two designed systems are environmentally friendly and economically viable. The total net present cost of the off-grid solution is $6,244, and its energy cost is $0.196/kWh. By contrast, the total net present cost of the on-grid system is $6,115, with energy cost equal to $0.183/kWh. The obtained results confirm the suitability of photovoltaic power systems for electrifying single households in addition to feeding the national grid.