Development of Solid Oxide Fuel Cell Based System in Stand Alone Mode

Several technologies are being used in distributed generation applications with variable degree of success. Among those are: wind turbines, small-scale hydropower plants, biomass, microturbines, photovoltaic arrays and fuel cells. In a fuel cell, the chemical energy incorporated in the fuel is converted directly to electricity and heat. Fuel cell technology is one of the most interesting energy conversion systems offering nearly zero emissions, flexibility of operation and high conversion efficiency. Increasing demand for power and the depletion of fossil fuels are providing opportunities for the development of fuel cells as power generating systems. In this paper the modeling of Solid Oxide Fuel Cell (SOFC) based generation system, fuel processor (methane reformer) and power conditioning unit (inverter) are presented. Within acceptable limits, the effects of load variation on output voltage, efficiency and fuel flow demanded are investigated. SOFC based generation system use a stack consisting of 384 fuel cells connected in series, this provides 120-140kW output power in stand-alone mode. The system has been analyzed when a step load is applied. Matlab-Simulink ® is used for the modeling and simulation of the fuel processor, fuel cell generator and power conditioning unit.