Performance characterization and techno-economic assessment of a novel PEMFC-GT hybrid system for aircraft applications based on prototype experiments

This study presents the development of a pioneering Proton Exchange Membrane Fuel Cell-Gas Turbine (FC-GT) hybrid system prototype, designed as a high-efficiency power source for electric propulsion aircraft. Ground-based principle validation and parametric experiments were conducted, demonstrating an electrical efficiency of 43% and a power-to-weight ratio of 0.75 kW/kg at a net power output of 105 kW, consistently outperforming fuel cell (FC) system. The results indicate that the performance of the FC-GT is co-driven by operating pressure and combustion temperature, necessitating an optimal balance between stack efficiency benefits and air subsystem parasitic losses to optimize global electrical efficiency. Notably, the experimental data-driven model reveals that the FC-GT system exhibits remarkable robustness at high altitudes, with efficiency degradation limited to only 2%, in contrast to a significant 10% drop observed in the FC system. Furthermore, the FC-GT configuration substantially broadens the power envelope, with its maximum output power nearly doubling that of an FC system utilizing the same stack, thus enabling flexible transitions between high-efficiency and high-power modes based on mission requirements. Additionally, the integration of the GT at high altitudes effectively reduces system parasitic power, resulting in up to a 30% reduction in unit power cost of the FC-GT system compared to the FC system. In conclusion, the FC-GT hybrid system demonstrates superior overall performance, positioning it as a highly competitive and sustainable power plant for next-generation electric aviation.