Technology pathway 1: SAF SAF includes biofuels made through various pathways such as hydroprocessed esters and fatty acids (HEFA), the Fischer-Tropsch process (FT) and alcohol-to-jet (AtJ), as well as synthetic aviation fuels made from captured carbon and low-emissions hydrogen electrolysis, known as power-to-liquids (PtL) or e-fuels. HEFA is currently the most mature, and likely to remain so until 2030, with 85%125 of announced SAF production facilities using this pathway. PtL is advancing rapidly and offers long-term scalability due to its reliance on renewable resources, but costs remain high. Regulatory frameworks, like the EU’s ReFuelEU initiative, are pushing for increased adoption, with targets of 70%126 SAF blends of which half (35%127) must be PtL by 2050 . Technology pathway 2: Aircraft design and air traffic management improvements Over the past decade, the aviation industry has made huge progress in making its aircraft and flight procedures more efficient. Within normal fleet turnover cycles, the replacement of retired aircraft with new, more efficient aircraft leads to regular efficiency improvements. Fuel efficiency measures in aviation, such as advanced engine designs and lightweight materials, are progressing rapidly but are still in early-stage development. Retrofitting winglets to aircraft wings could be a short-term solution to reducing emissions. Continued investment is essential in enhancing fuel efficiency for conventional engines, along with improved airframe design, ground operations, ATM and route planning. Other advancements such as reducing cabin weight or switching to electric taxiing, optimized approach/departure procedures, vertical speed inefficiency reductions during cruise from improved aerodynamics, improved congestion management, single-engine taxiing, and engine washes also offer potential for reducing emissions. Technology pathway 3: Novel propulsion technologies Novel propulsion technologies in aviation, such as hydrogen fuel cell/combustion, battery-electric and hybrid-electric aircraft are gaining momentum but at large prototype and demonstration stages of readiness and expected to be commercially available by 2030. Hydrogen-powered aircraft, like Airbus’ ZEROe concept,128 aim for commercial availability by 2035, with a TRL of 5-6, still in large prototype stages. For hydrogen, key challenges include its production, transportation and assessing its environmental impact (e.g. contrail formation when burned). Battery-electric aircraft, while promising for short-haul flights, currently suffer from low energy density, holding just one-fiftieth of the energy of jet fuel by weight. The main challenge with battery-electric aircraft is using batteries with high enough energy density, which do not exist for large passenger planes, limiting their potential application to small and short-range flights. Hybrid-electric aircraft, which combine traditional fuel with electric propulsion, are closer to commercialization and are expected to play a crucial role in the near term. Hybrid-electric aircraft, like the Ampaire Electric EEL,129 are at demonstration phases (TRL 6-7), targeting broader use by 2030. Net-Zero Industry Tracker: 2024 Edition 7

Net Zero Industry Tracker 2024 Aviation