Power Loss Analysis of Hybrid PV and PEMFC Storage Integration System Using Fault Tree Analysis

Abstract

Dwindling deposits of fossil fuels have caused renewable energy systems to gain more grounds as alternative power sources. In this research, analysis is made into the main contributors of power losses realized in the stand-alone hybrid combination of photovoltaic and fuel cell systems, where the fuel cell system serves as a storage device. Test of feasibility of the proposed hybrid system indicates that the installed capacity of the hybrid system ought to be greater than the load demand or that the load demand should reduce at certain periods of the day to ensure power supply to the electrolyser of the proton exchange membrane fuel cell. Fault Tree Analysis (FTA), performed with the help of Functional Block Diagrams (FBD) on possible configurations of the hybrid system, shows the contributions made by the hybrid components toward power losses in the system. Critical components i.e. components whose failure or combined failure may cause total failure of the system, were identified to be the inverter and the consumer unit. Other components worthy of continuous monitoring were the PV panel, the charge controller and the battery. Failure rate analysis on these components showed that the inverter and consumer units had percentage failure probabilities of 44.929 % and 29.653 % respectively. Minimal cut set (i.e. likely cut set), made up of the combined effect of the inverter and the consumer unit, proved to be a liable source of power failure with high failure probability of 1.462E-01. Likely cut set consisting of combinations of PV panel, charge controller and battery, have failure probability of 4.1811E-04. Hence, using high quality inverters, consumer units and charge controllers as well as keeping spares may well sustain the system for extended operation. This research offers pragmatic ways of identifying components that may affect power delivery of the proposed hybrid system.