Impact of technology trajectories on the performance, emissions, life cycle aspects and sustainability assessment of future net zero regional aircraft variants

Abstract

The sustainability assessment of five Net Zero regional aircraft variants assuming entry into service by 2035 and 2050 is presented. Sustainable Aviation Fuelled, Hydrogen Gas Turbine, Full Electric, Hybrid Electric and Fuel Cell-Electric variants are evaluated. The impact of technology trajectories at aircraft level is analyzed in terms of payload-range capabilities, tailpipe carbon emissions and energy consumption per passenger. The efficiency and carbon intensity of energy and fuel production infrastructures are combined with overall sustainability metrics that include engineering, environmental, social, economic and policy factors. Variations in the ranking of the Net Zero aircraft variants are analyzed along with the strong dependencies of the outcomes on the technology trajectories, choice of metrics and level of evaluation considered. The influence of coupled multi-spatial and temporal factors on the sustainability outcomes is further discussed. Although zero tailpipe emission variants are feasible, early entrants with conservative technology targets cannot meet the baseline payload range capabilities and lead to large variations in energy efficiency at aircraft level. For these technology levels SAF variants offer the highest potential in mission energy improvements ~4% while all other variants lead to an energy penalty compared to the baseline. Advanced versions of the variants converge with similar energy savings close to ~13% for 2035 and ~23% for 2050. Compared to SAF, advanced hybrid electric variants could also lead to tailpipe carbon reductions of 15%-20% and ~35% for 2035 and 2050 respectively. Two energy scenarios are used to estimate the life cycle carbon emissions of these aircraft, utilizing projections for 2030 and 2050. Under 2030 energy infrastructure scenarios, hydrogen aircraft produce higher life cycle emissions than contemporary aircraft, while SAF variants, when accounting for carbon reuptake, demonstrate benefits. With the 2050 energy infrastructure scenarios, all aircraft configurations and technology projections achieve reduced life cycle emissions compared to contemporary aircraft. The study demonstrates that aircraft emissions and sustainability are dependent on both aircraft technology and energy infrastructure, with discussions concluding on the impacts that these technologies have to aviation sustainability.