GHG emissions evaluation of conventional, electric, hybrid, biofuel, and hydrogen aircraft

Understanding the environmental repercussions of regional and medium to long-range aircraft operations are indispensable for the ensuring the sustainable growth of aviation sector. Therefore, this study investigates the environmental impact of different propulsion technologies and focus on the direct and indirect GHG emissions of conventional, electric, hybrid, biofuel, and hydrogen-powered regional aircraft. Additionally, the GHG emissions associated with medium to long-haul aircraft are estimated for conventional, biofuel, and hydrogen-fueled aircraft in order to highlight their environmental impact also. We formulated a model to assess fuel consumption and GHG emissions related to specific aircraft technologies. Within a regional flight ranging up to 400 km, the results demonstrate that conventional aircraft produce 15.4 % more direct GHG emissions than hybrid aircraft with a 50 % hybridization degree. The utilization of biofuel (Jatropha Bio-synthetic Paraffinic Kerosene) in regional setting is found to be 7.4 % more sustainable than its conventional counterpart in direct emissions. Hybrid, electric, biofuel, and hydrogen (derived from electrolysis method from renewable resource such as wind and solar) aircraft are respectively 15.3 %, 87.2 %, 10.7 %, and 99.7 %, 96.9 % more environmentally sustainable than conventional aircraft when it comes to total emissions (direct and indirect) in regional aviation. Further, hydrogen powered aircraft's emissions (hydrogen derived from conventional source such as natural gas via steam methane reforming method) are also estimated and compared with jet A1 fuel. The findings reveals that total GHG emissions from hydrogen, produced from non-renewable source are 5.5 % more environmentally friendly in regional and 14.8 % in medium to long range.