The Potential of Hydrothermal Liquefaction Fuel to Decarbonize the Aviation Sector
Main Presenter: Benjamin W. Portner
Co-Authors: Leonard Moser Christina Penke Valentin Batteiger
Hydrothermal Liquefaction (HTL) is a thermochemical process, which can produce transportation fuels from a wide range of biogenic raw materials, such as forestry residues, straw, sewage sludge, manure or microalgae. Thanks to its feedstock flexibility, HTL bears the potential to produce large amounts of fuel, and thereby contribute significantly to decarbonize the aviation industry. In our study, we estimate the environmental impact of HTL kerosene production from manure with the help of a Life Cycle Impact Assessment (LCIA). Our results show that HTL kerosene significantly reduces the carbon footprint compared to petroleum-based kerosene (-50%). Looking at the origin of impacts within the production system, we find that large contributions come from the use of process energy and from the feedstock itself. The latter impact is dominated by consequential effects, e.g. the necessity to produce artificial fertilizers to replace manure, which would otherwise be used in agriculture. Another large but uncertain contribution comes from the treatment of discharged wastewater, whose composition is not well-covered in the existing literature – a knowledge gap we recommend closing in future studies. Lastly, we explore the global production potential of HTL kerosene and compare it against other sustainable aviation fuel (SAF) options, such as state-of-the-art Hydrotreated Esters and Fatty Acids (HEFA). We find that HTL’s potential exceeds that of HEFA significantly, surpassing world aviation fuel demand by 100-500%.