Fuel utilization effects on system efficiency in solid oxide fuel cell gas turbine hybrid systems

[Display omitted] •SOFC-GT hybrids were designed for various levels of SOFC fuel utilization, Uf.•System efficiency was high, >70% LHV, between 65 and 90% Uf using syngas fuel.•Lower Uf increased the Nernst potential and GT inlet T, while SOFC size dropped.•Peak efficiency was found with SOFC only providing 65% of the power share.•Hybrid designs with 40–60% output power from SOFC had comparable economics. A computational analysis was conducted to optimize the design of a solid oxide fuel cell - gas turbine hybrid power generator, focusing on the impact that fuel utilization within the fuel cell has on system efficiency and installed costs. This is the first ever design-study considering the effect of fuel utilization on performance, as well as on the optimum power split. This hybrid system attained high electric generation efficiencies (>70%) over a wide range of operating conditions (60%