Energy, exergy and sustainability analyses of hybrid renewable energy based hydrogen and electricity production and storage systems: Modeling and case study

In this study, hybrid renewable energy based hydrogen and electricity production and storage systems are conceptually modeled and analyzed in detail through energy, exergy and sustainability approaches. Several subsystems, namely hybrid geothermal energy-wind turbine-solar photovoltaic (PV) panel, inverter, electrolyzer, hydrogen storage system, Proton Exchange Membrane Fuel Cell (PEMFC), battery and loading system are considered. Also, a case study, based on hybrid wind-solar renewable energy system, is conducted and its results are presented. In addition, the dead state temperatures are considered as 0 degrees C, 10 degrees C, 20 degrees C and 30 degrees C, while the environment temperature is 30 degrees C. The maximum efficiencies of the wind turbine, solar PV panel, electrolyzer, PEMFC are calculated as 26.15%, 9.06%, 53.55%, and 33.06% through energy analysis, and 71.70%, 9.74%, 53.60%, and 33.02% through exergy analysis, respectively. Also, the overall exergy efficiency, ranging from 5.838% to 5.865%, is directly proportional to the dead state temperature and becomes higher than the corresponding energy efficiency of 3.44% for the entire system. (C) 2012 Elsevier Ltd. All rights reserved.