Impact on contrails coverage when flying with hybrid electric aircraft

Abstract

iation is responsible for approximately 5% of global warming and is expected to increase substantially in the future. In the face of the continuing expansion of air traffic, mitigation of the aviation’s climate impact becomes challenging, but imperative. Among various mitigation options, hybrid electric aircraft (HEA) has drawn intensive attention due to its large potential in reducing the greenhouse gas emissions. The non-CO2 effects (especially the contrails) of the HEA on the climate change, however, remains ambiguous. As the first step to understand the climate impact of HEA, this research aims to investigate the impact on the formation of persistent contrails when flying with HEA. The simulation is performed using the Earth System model (EMAC) coupled with a CONTRAIL submodel, where the Schmidt Appleman Criterion (SAC) is adapted to estimate changes in the potential contrail coverage (PCC) globally. The analysis shows that the HEA forms contrails at relatively lower temperature than conventional aircraft. At the same altitude, the reduction in contrails formation is mainly observed in the tropical regions where the temperature is warmer. With a smaller fraction of electric power in use, the contrail coverage remains nearly unchanged. As the degree of hybridization increases further to 90%, an exponential reduction in the contrail formation is expected with a maximum value of about 40%.