Techno-economic assessment for optimised renewable jet fuel production in Sweden

Abstract: The aviation industry contributes to more than 2% of global human-inducedCO2-emissions, and it is expected to increase to 3% by 2050 as demand for aviation grows. As the industry is still dependent on conventional jet fuel (CJF), one of the key elements to help decarbonise the industry is to transition to renewable jet fuel (RJF). The aim of this thesis is to investigate the techno-economic and environmental impacts of RJF production from lignocellulosic biomass and captured CO2 sources in the aviation transport of Sweden. The studied production pathways namely Fischer-Tropsch (FT), Hydrothermal liquefaction (HTL) and Power-to-liquids (PTL), all produce RJF which can be blended with CJF, known as drop-in fuels. The potential to produce RJF in Sweden has been investigated in a MILP optimisation model developed in Python 3.9, considering technological, economic, environmental and spatial parameters of FT, HTL and PTL. In addition to the three pathways, CJF and Hydroprocessed Esters and Fatty Acids (HEFA) have also been included for comparison in the model by considering their current market prices. Four scenarios were developed to investigate how the RJF production is inuenced by factors such as raw material availability and policies such as a carbon tax and blending mandate. The assessment period was 2020-2050. From the modelling, HTL and PTL were chosen to meet the jet fuel demand required by the blending mandate, while the rest of the demand from airports was met by CJF. In the reference scenario, the total RJF production increased during the time frame due to the gradually increasing blending ratio, amounting to 3.85, 9.14 and 16.87 TJ for 2030-2050. The CJF amount was 11.37, 10.42, 8.78 and 5.62 TJ from 2020-2050, as the blending ratio was set to 0% in 2020. By implementing the blending mandate, a total emissions reduction potential of 38.7% was obtained in 2050 compared to the continued use of CJF. The unit production cost, encompassing the CAPEX, xed, variable and feedstock cost, for HTL was 24.2-25.4 SEK/litre and 16.7-22.0 SEK/litre for PTL in 2030-2050. The HTL and PTL jet fuel produced from this study would not be economically feasible in comparison to CJF or HEFA with their current market prices of 2.35 and 10.81 SEK/litre, respectively. However, by taking into account the revenues from the by-products diesel and gasoline, a unit production cost of 8.6 SEK/litre and 14.31 SEK/litre is obtained for HTL and PTL, respectively. Additionally, by imposing the penalty fee of 6 SEK/kgCO2, eq to suppliers if they fail to meet the blending mandate, HTL and PTL can reach price parity with CJF. The study results indicate that the use of drop-in RJF has a great potential to help decarbonise the aviation industry and provide low-emission alternatives to CJF. However, the investigated conversion pathways are currently not economically feasible in comparison to CJF. Therefore, policy instruments such as the blending mandate are essential to help promote the production of and support the integration of RJF in Sweden.