A recent review of aviation fuels and sustainable aviation fuels

Aviation fuels are essential for flight transportation. The increasing demand for such fuels threatens the present efforts to mitigate global warming. Changing to renewable energy sources and hydrogen to drive airplanes is not ready and will take a few decades. Therefore, alternative fuels such as sustainable aviation fuels (SAFs, also so-called bio-jet fuels) could play an excellent role in mitigating greenhouse emissions. SAFs encompass blends of bio and synthetic fuels. Some SAF pathways have already been certified (such as oil-to-jet, alcohol-to-jet, gas-to-jet, and sugar-to-jet), and some are on the way to being certified. This review starts by providing a detailed overview of the current status of aviation fuels, including their growth, types, and emission trends. After that, it comprehensively delves into a thorough discussion of SAFs, covering various aspects such as their types, combustion properties, production technologies and pathways, cost evolution, and life cycle assessments. The paper discusses the SAFs' future prospects while providing practical recommendations based on the analysis. It was shown that the oil-to-fuel (HEFA) pathway is more mature with less carbon emissions. SAFs face challenges, including high costs, limited production scale, feedstock availability, energy-intensive production methods, land-use competition, potential indirect environmental impacts, certification standards, infrastructure, and public acceptance. Much research is needed to reduce SAF costs substantially less than conventional aviation fuels.