In October 2022, all member states of the International Civil Aviation Organization (ICAO) committed to a net-zero CO2 future by 2050, marking a significant shift from compensating for emissions to actively reducing them in aviation. This commitment acknowledges the critical role of reducing greenhouse gas emissions in the transport sector, especially since aviation accounts for 12 percent of carbon emissions and 2 percent of all global energy-related emissions. The aviation industry and governments must make careful choices to transition towards sustainable aviation, adopting sustainable aviation technologies (SATs). This research focuses on identifying stakeholder preferences towards these SATs to facilitate their successful adoption, filling a significant gap in existing literature.
The study addresses the research question: "What are stakeholder preferences towards sustainable aviation technologies for the transition to net zero CO2 aviation in 2050?" The Best-Worst Method (BWM), a Multi-Criteria Analysis approach, was chosen to explore these preferences. The research is divided into four sections: identifying promising SATs, establishing relevant evaluation criteria, obtaining weights for these criteria based on stakeholder preferences, and determining SAT performance scores.
Initially, the study identified promising SATs, categorizing them into hydrogen, electric, electrofuels, and biofuels. Electric technologies were excluded for medium- and long-haul flights due to their unsuitability. The specific SATs identified for potential adoption included Liquid Hydrogen with PEM fuel cell aircraft (LH2), HEFA-produced biofuel with used cooking oils (HEFA), and n-octane electrofuel.
The second section established evaluation criteria based on an extensive literature review and frameworks like Feitelson & Salomon’s political economy of transport innovations and the Triple Bottom Line theory. Three main criteria were established: Environmental, Economic, and Technological performance, each encompassing three sub-criteria. These sub-criteria include greenhouse gas emissions, water consumption, land use impact (Environmental); minimum jet fuel selling price, investment costs, operational costs (Economic); and technological readiness level, scalability, efficiency (Technological).
The third section utilized the Bayesian BWM to determine optimal weights for these criteria from stakeholder perspectives. Data from semi-structured interviews with eleven stakeholders from the aviation industry, categorized into airline, expert/advisor, and producer/manufacturer groups, provided the necessary input. The analysis revealed that "Greenhouse gas emissions" were the most critical sub-criterion, followed by "Operational costs" and "Land use impact". Variations in weightings among stakeholder groups were noted, with airlines prioritizing Economic performance and experts/advisors emphasizing Technological performance.
Finally, the study applied the Weighted Sum Method (WSM) to combine SAT performance scores with the obtained weights, determining the final scores for the years 2024, 2030, and 2050. HEFA consistently emerged as the top SAT across all stakeholder groups for all years, except for the expert/advisor group in 2050, where n-octane ranked highest. The preference for HEFA was due to its consistently high scores across most sub-criteria, though the gap between SATs decreased by 2050 due to improvements in LH2 and n-octane’s greenhouse gas emissions performance.
In conclusion, HEFA is generally the most preferred SAT for transitioning to net-zero CO2 aviation by 2050. However, these findings are indicative, given the limited number of interviews, suggesting further research with more extensive stakeholder engagement to ensure representativeness and mitigate potential biases.