Optimization of Hybrid Power System for Cost Minimization: Case Study of a University Library

Abstract

The unprecedented increase in electricity consumption around the globe continues to place an enormous burden on national power grids, particularly during peak demand periods. The frequent load shedding in South Africa is a major concern for universities; hence, there is a need to find alternative sources in form of renewable energy sources (RES) or hybrid systems. Outages on campuses could lead to loss of revenues and quality time; which may include the cost of sustaining teaching, learning, and research. This study aims to ensure continuous supply to critical loads such as a university library using a hybrid system of diesel generator, solar PV, and battery storage at minimum cost. A non-linear objective function is formulated such that the library load is met by RES when available with the battery otherwise the diesel generator (DG) is switched on. A MATLAB function called “quadprog” is used to solve the optimization problem. The results show that the hybrid system performs better than the DG only with fuel cost reductions of 31% and 22.3% for summer weekdays and weekends respectively and 29.3% and 40.7% for winter weekdays and weekends respectively.