Optimal Sizing of the Energy Sources in Hybrid PV/Diesel Systems: A Case Study for Malaysia

This article presents optimization of hybrid photovoltaic (PV)/diesel systems for five regions in Malaysia. The PV array, storage battery, and diesel generator capacities are the variables to be optimized, considering very low loss of load probability. In the proposed optimization method, a hybrid PV/diesel system model is developed using a long-term solar energy series and a defined load demand. The objective of the optimization problem is to minimize the system cost and to determine the optimal sizing of PV array, storage battery, and diesel generator in terms of its unit cost. As a result, for an optimal sizing of hybrid PV/diesel generator for Malaysia, the PV array capacity must be 1.12 times the load demand, the diesel generator capacity must be 0.3 times the load demand, and the optimum storage battery size must be 0.29 times the load demand. The proposed PV/diesel system is validated by comparing it with a benchmark system. This system supplies the load demand of a school located in the state of Sabah. The load demand of this school is 1012 kWh/day during working days and 812 kWh/day during weekends and holidays. This load is supplied by a 150 kW diesel generator and a 35 kWp PV array without backup batteries. The comparison is based on the lifetime cost of the system that leads to the kWh unit price.