A comparative life cycle assessment of clean aviation fuels. (1st November 2021) - Siddiqui, O.
Abstract: In this study, life cycle assessments and comparative evaluations are performed for different types of renewable and alternative fuels for aircrafts. The life cycle impacts of both hydrogen and ammonia fuels are primarily investigated considering conventional and renewable energy-based routes. The overall life cycle impacts of several hydrocarbon fuels including kerosene, ethanol, methanol, dimethyl ether, and biodiesel are also studied. The steam methane reforming-based route for hydrogen and ammonia fuels is found to have higher global warming potentials as compared to alternative production routes. High phosphate emissions result in a higher freshwater eutrophication potential for the solar-based route for ammonia fuel. Fossil fuel-based dimethyl ether is found to have a comparatively higher global warming potential of 1.3 kgCO2 equivalent per tonne-km amongst the considered hydrocarbon fuels that include ethanol (1.1 kgCO2 equivalent per tonne-km), kerosene (1.04 kgCO2 equivalent per tonne-km), methanol (1.01 kgCO2 equivalent per tonne-km), and biodiesel (1.07 kgCO2 equivalent per tonne-km). Dimethyl ether is found to entail high toxicity potentials and the reduction of life cycle arsenic, barium, cadmium, chromium, cobalt, and lead emissions is recommended. However, higher photochemical ozone formation potentials of 0.0055 and 0.0046 kgNOx equivalent per tonne-km are associated with biodiesel and kerosene fuels respectively. Highlights: Comparative life cycle assessment of different alternative aviation fuels. Solar-based hydrogen fuel found to entail higher ionizing radiation potential. Dimethyl ether fuel found to have global warming potential of 1.3 kgCO2eq /tkm. Biodiesel entails photochemical ozone formation potential of 0.0055 kgNOxeq /tkm.