Date of Award

2021

Degree Type

Thesis

Degree Name

Master of Science in Systems Engineering

Department

Mechanical, Industrial and Systems Engineering

First Advisor

Valerie Maier-Speredelozzi

Abstract

The aviation industry is currently assessing and developing alternative technologies to power aircraft in order to reduce their high environmental impact contribution. Fuel cell systems are investigated as a potential alternative for conventional powertrains and could be an option for heavy duty missions, like long-range flights. To ensure sustainable development of long-range aircraft powered by fuel cell systems, research and development teams should be aware of their critical environmental issues. In contrast to other fuel cell applications, Life Cycle Assessment (LCA) studies on long-range aircraft are hardly available. To close this research gap, this study models the environmental impact of a fuel cell powered aircraft shuttling from Frankfurt, Germany to Boston, USA using the software Brightway2. As a preparation for this case study, a literature review is presented regarding the state-of-the-art and the state-of-research for fuel cells in aviation, hydrogen supply and infrastructure, and LCA studies on fuel cell powered aircraft. Based on this literature review, a system model is developed and analyzed with respect to the critical environmental issues. The LCA case study assesses the reference aircraft’s fuel cell powertrain subsystems including the hydrogen supply chain, the fuel cell stack, and the cryogenic tank individually as well as in a combined system over its lifetime. The environmental performance is evaluated considering six ReCiPe midpoint impact categories (GWP, TAP; FEP, MEP, MDP, FDP). Regarding the hydrogen supply a total of 24 hydrogen production scenarios including different energy sources and geographic locations (US and Germany) are considered in the analysis. The hydrogen production impact was found to be very sensitive to geographic and energy source influences. Regardless of the production location, the best environmental system performance was achieved when producing hydrogen by PEM electrolysis with wind energy. Furthermore, the LCA analysis revealed the platinum load of the catalyst and the carbon fiber of the tank as critical components. Overall, the hydrogen production was identified as the greatest impact contributor over the system’s lifetime whereby the energy demand and electricity source were determined as the most crucial parameters.

Available for download on Friday, August 11, 2023

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