Abstract
Between 2010 and 2050, aviation-related greenhouse gas (GHG) emissions are projected to increase 3.6- to 6.2-fold due to rapid sectoral growth, while global GHG emissions should reduce by 40-70% to realize the climate mitigation ambitions outlined in the 2015 Paris Agreement. Renewable jet fuel (RJF) produced from biomass is one
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of the main options to structurally reduce aviation-related GHG emissions. However, current consumption of RJF is negligible, mainly due to high production costs. This thesis addresses the production costs, climate impact and future supply of RJF. Chapters 2-5 quantify the production cost and climate impact for a wide range of RJF production systems. Chapter 6 models the future supply of RJF in the EU towards 2030 and analyzes the impact on other bio-based sectors. The production cost of RJF likely remains higher than fossil jet fuel in the short (2020) and medium term (2030). The Hydroprocessed Esters and Fatty Acids (HEFA) pathway shows the lowest production costs in the short term, while Hydrothermal liquefaction (HTL) and Pyrolysis provide promising alternatives in the medium term. The average price premium of RJF relative to fossil jet fuel is projected to decline from +217% to +45% between 2021-2030, because of increasing oil prices, the commercialization of novel conversion technologies, access to cheaper feedstocks and technological learning. Optimized supply chain design and co-production strategies with existing industries (e.g. pulp mills or refineries) could reduce RJF production costs by up to 20%. The climate impact of RJF from CO2, CH4 and N2O emissions varies between conversion pathways and production contexts, but can be significantly lower than fossil jet fuel. The majority of investigated RJF conversion pathways reduce life-cycle GHG emissions by more than 70%, particularly when produced from residues and lignocellulosic crops. The Relative Climate Impact indicator introduced in Chapter 5 shows that time-dependent emissions, associated with land use change, carbon debt and foregone sequestration, can exceed life-cycle emissions and may delay, limit or even eliminate the climate change benefits of RJF. However, the risk of these emission fluxes can be effectively mitigated by shaping the right production context. The future supply of RJF mainly depends on policy incentives, the pace of technology development, and biomass supply and demand. Based on the anticipated regulatory context in the EU between 2021-2030, RJF supply could increase to 165-261 PJ yr-1 (3.8-6.1 Mt yr-1) in the EU by 2030, which covers 6-9% of EU jet fuel consumption and 53-84% of projected emission growth. The cumulative costs over 2021-2030 were estimated at €7.7-11 billion, which translates to approximately 11-16 € GJ-1 RJF (491-682 € t-1), 160-222 € t-1 CO2 abated, or 1.0-1.4 € per departing passenger on intra-EU flights. In sum, RJF can reduce the climate impact of the aviation industry in the coming decade, provided 1) RJF producers guarantee robust climate impact reductions, 2) technology developers are supported to commercialize new conversion technologies and reduce costs, and 3) governments and aviation stakeholders develop a structural financing mechanism to cover the cost differential between RJF and fossil jet fuel.
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