Thermodynamic performance optimization and environmental analysis of a solid oxide fuel cell powered with biomass energy and excess hydrogen injection

Recently the energy systems' developers focused on the efficient exploitation of renewable resources and novel technologies to decrease fossil fuel consumption and environmental damage. The SOFC units are known in this regard as high-efficiency and versatile fuel-driven systems, for which the biofuel from biomass gasification is an abundant and clean fuel source. The current article investigates a biomass-driven SOFC that is hybridized with wind turbines in order to increase the hydrogen concentration of intake fuel. To do so, the generated electricity by wind turbines is given to a polymer electrolyte membrane electrolyzer for hydrogen generation and injection into the SOFC. Feasibility studies of the proposed framework are conducted based on thermodynamic laws, and its performance enhancement is appraised using three exergy-based environmental indices. A parametric study is carried out to indicate the influence of operating variables on system performance in terms of power output, exergy efficiency, and environmental indices, after which a multi-objective optimization is implemented. The results indicated significant efficiency enhancement of biomass-driven SOFC via integration with wind turbines for hydrogen injection. It is found that more power from wind turbines leads to more hydrogen input to the SOFC and increases net power as well as efficiency. Increasing the fuel utilization factor for the basic structure and the structure with HI, the exergetic efficiency decreases by 5% and 4%, respectively. Under optimal point, the overall system's environmental damage factor and net output power are found to be 0.0092 kW and 322 kW, respectively.