(630a) Design, Analysis, Operation and Control of a Photovoltaic/PEM Fuel Cell/Nicd Battery Hybrid Renewable Energy System (HRES) for Urban Transit Applications

Authors: Zachary S. Whiteman, Piyush Bubna, Ajay K. Prasad and Babatunde A. Ogunnaike

          A hybrid renewable energy system (HRES), a system consisting of two or more individual renewable energy systems utilized simultaneously to meet an energy demand, potentially allows one to take advantage of complementary strengths of renewable resources in meeting energy demands in both stationary and mobile applications. Because they take advantage of multiple renewable resources, HRESs may represent a cheaper and more dependable alternative to stand-alone renewable energy systems. This presentation is concerned with a hybrid system for mobile applications, specifically, the combination of a roof-installed photovoltaic array with a PEM fuel cell/NiCd Battery bus currently operating shuttle routes on the University of Delaware campus.  The primary objectives are: (i) to design the hybrid system (and an appropriate control system) to satisfy required energy demands effectively but with reduced hydrogen consumption; and (ii) to analyze the economic impact of the installation of a photovoltaic array on the PEM fuel cell/NiCd battery bus.  

          The study is based on actual solar irradiance data collected from a measurement device installed on the roof of the existing HRES bus which was incorporated into a Simulink model developed for the Photovoltaic/PEM fuel cell/NiCd Battery HRES.  Control strategies for maintaining the desired state of charge of the NiCd battery while meeting the total energy demand of the bus were designed and implemented on the complete HRES model simulating real shuttle runs under various operating conditions. An economic analysis of the photovoltaic investment required for realizing the HRES process design was also carried out to determine the break-even period for photovoltaic array efficiencies and photovoltaic array surface areas ranging between 5% - 100% and 5m² - 100m² respectively. The presentation will highlight the energy management and operational performance of the control strategies as well as the economic implications of modifying the existing PEM fuel cell/NiCd HRES bus.