Study on the comprehensive performance of a hybrid power system based on hydrogen-driven solid oxide fuel cells for green unmanned aerial vehicles

Abstract

To reach the Net Zero target, the aviation industry requires low-carbon development strategies. Hydrogen-driven solid oxide fuel cells (SOFCs) present a promising green power source, offering zero-carbon emissions and high energy efficiency. However, most current SOFC studies focus on maximizing efficiency in ground applications, which limits their applicability in aviation due to their low power-to-weight ratio. This paper explores a hybrid power system combining SOFCs and gas turbines for long-endurance unmanned aerial vehicles (UAVs). In this system, the SOFC enables highly efficient power generation while also supplying waste heat for recovery by the gas turbine, thereby improving both system efficiency and the power-to-weight ratio. Four configurations of the hybrid power system are compared during both the takeoff and cruise phases. The optimal setup is further analyzed to assess the effects of operational parameters, such as SOFC fuel utilization and compressor pressure ratio. Simulation results indicate that the SOFC-based hybrid power system achieves a system efficiency of 42.25 % during the takeoff phase and 52.01 % during the cruise phase, significantly higher than conventional micro gas turbine power systems. The power-to-weight ratio is 0.7747 kW∙kg⁻¹, a substantial improvement over conventional SOFC-based UAV power systems (approximately 0.3 kW∙kg⁻¹). Compared to traditional UAV power systems, the hybrid system—utilizing natural gas steam reforming and carbon capture and storage technology for hydrogen generation—can reduce carbon dioxide emissions by 72.47 %.