Title: Direct alcohol vs. alcohol-to-jet SPK utilisation in commercial aviation - an energetic-operational analysis

Authors: Nils Bullerdiek; Steffen Voß; Ulf Neuling; Martin Kaltschmitt

Addresses: Institute of Environmental Technology and Energy Economics (IUE), Hamburg University of Technology (TUHH), Eißendorfer Straße 40, 21073 Hamburg, Germany ' Institute of Environmental Technology and Energy Economics (IUE), Hamburg University of Technology (TUHH), Eißendorfer Straße 40, 21073 Hamburg, Germany ' Institute of Environmental Technology and Energy Economics (IUE), Hamburg University of Technology (TUHH), Eißendorfer Straße 40, 21073 Hamburg, Germany ' Institute of Environmental Technology and Energy Economics (IUE), Hamburg University of Technology (TUHH), Eißendorfer Straße 40, 21073 Hamburg, Germany

Abstract: To support renewable energy utilisation in aviation apart from kerosene-based sustainable aviation fuel (SAF), a direct use of renewable alcohols (methanol, ethanol, propanol, butanol, pentanol) is analysed and compared to their use as alcohol-to-jet (ATJ) conversion intermediates. The energy demands in the form of alcohol and operational payload-range implications are analysed for two aircraft types, using a Bréguet range equation and a mass/energy balance approach. From an energetic perspective a direct alcohol usage is significantly more efficient compared to the ATJ pathway requiring 40% to 60% more alcoholic energy. Even considering low process losses and high kerosene fractions (95%), the ATJ conversion still requires about 16% (26% for methanol) more alcoholic energy. Especially for methanol and ethanol that lead to significant payload-range losses compared to kerosene of approx. 70% and 50%. These effects are less significant for propanol, butanol, and pentanol with range reductions of 40%, 30%, and 25%.

Keywords: sustainable aviation fuel; SAF; alcohol-to-jet; ATJ; payload-range; Bréguet; methanol; ethanol.

DOI: 10.1504/IJSA.2022.124483

International Journal of Sustainable Aviation, 2022 Vol.8 No.3, pp.260 - 298

Received: 10 Jan 2022
Accepted: 04 Mar 2022
Published online: 27 Jul 2022 *

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