Inflight Sustainability: Harmonizing Certification Standards for Sustainable Aviation Fuel Adoption

Abstract The aviation industry’s commitment to reducing greenhouse gas (GHG) emissions has led to the adoption of Sustainable Aviation Fuel (SAF). Ensuring SAF’s sustainability necessitates robust certification systems, notably the Roundtable on Sustainable Biomaterials (RSB) and International Sustainability and Carbon Certification (ISCC). This review synthesizes existing literature and critically analyzes and compares the sustainability criteria of RSB and ISCC within the framework of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). As of 2024, a third scheme, the Nippon Kaiji Kyokai (ClassNK), has also been approved by the International Civil Aviation Organization (ICAO); this study provides a qualitative overview of ClassNK’s criteria and assessment structure. Our comparative thematic analysis reveals that RSB emphasizes comprehensive lifecycle GHG accounting and innovative feedstock management, dedicating approximately 48.6% of its criteria to GHG emissions management. In contrast, ISCC focuses on good agricultural practices and social responsibility, with 33.7% of its criteria addressing agricultural practices and 28.4% dedicated to social responsibility. Both systems share common ground in areas such as biodiversity conservation and ecosystem management. However, they differ in their approaches to feedstock management and lifecycle GHG assessments. These differences can lead to increased compliance costs and complexities for SAF producers. Harmonizing RSB and ISCC standards could streamline certification processes, reduce redundancies, and enhance the scalability of SAF production. Such alignment would support the aviation sector’s decarbonization efforts. The approval of ClassNK underscores the evolving nature of the certification landscape. Its tiered approach to assessing environmental themes while delegating social criteria to national or operator reporting is discussed. Implications for policy, stakeholder engagement, and future SAF certification frameworks are considered to underline the broader significance of harmonization efforts.