Future Propulsion Systems and Energy Sources in Sustainable Aviation

5Promising Technologies in Propulsion and Power

5.1 Introduction

Aviation contributes to about 12% of the greenhouse gas emissions in the transportation sector (i.e. road transport, rail, aviation, and shipping). Transportation sector itself accounts for about 31% of the US carbon dioxide emissions based on Environmental Protection Agency (EPA) report (2016). Hence, aviation's share in anthropogenic CO₂ emissions is currently about 4%. The importance of aviation to environmental concerns is thus not tied to its current 4% value rather to it is rising trends. The long‐term impact potential is extremely harmful when the estimated 16B passengers take to sky in 2050. Within the aviation sector, commercial aviation contributes 93% to carbon dioxide emissions, whereas business jets, general aviation aircraft, helicopters, and UAS contribute the remaining 7%, as shown in Figure 5.1. Thus, to create a low‐carbon aviation future, we focus on promising low‐carbon‐footprint propulsion and power systems for commercial aviation. We expect that the spinoffs of this large‐scale technology development effort in commercial aviation to impact all sectors of flight.

The road to sustainable propulsion and power systems in commercial aviation goes through advanced gas turbine (GT) engines either as fully integrated propulsion‐airframe system or as hybrid electric propulsion system (HEPS). The rationale for continued investment and reliance on advanced gas turbine (GT) engines, in particular, advanced ...