Investigating the potential of parallel hybrid-electric retrofit of narrow-body airliner for emission reduction

Due to the high power and energy demands of large aircraft and low energy density of batteries, parallel hybrid-electric propulsion (HEP) is an in-between solution to reduce carbon emissions instead of full-electric propulsion. Considering the long in-service time, parallel HEP retrofit of existing large commercial or transport aircraft is favorable for technical risks and economic values. To enhance the reliability of the analysis, a comprehensive parallel HEP retrofit study of a narrow-body airliner is carried out in this paper. At first, efficient and accurate aerodynamic and engine deck surrogate models are built to include multidisciplinary impacts. To capture the off-design performance, a detailed flight mission is modeled based on exact flight dynamic equations, which is solved in a time-stepping manner. Then, the hybridization levels and battery usage strategy are thoroughly investigated. Besides, fuel burn, carbon emissions, and total energy consumption performance is studied for fixed take-off weight and selected flight range scenarios. The results show that the total energy in flight can be reduced by 7.9% and fuel combustion and carbon emissions can be reduced by 13.2% for the 2000 km flight distance case compared to the reference case. The greenhouse gas (GHG) emission reductions are 3059.8 kg CO2, 1220.0 kg H 2 O, 0.1937 kg SO 4 , and 0.0387 kg soot. As our methods have incorporated reliable multidisciplinary data and off-design features, the results and conclusions on the parallel HEP retrofit of large aircraft for carbon emission reductions and sustainable aviation goals are more relevant.