During his PhD studies, Zhiyuan Xie examined hydrogen amid high uncertainty and mapped where it can be produced and used, how it works alongside other technologies, and what a realistic scale could look like in the future. By comparing many system-wide pathways, he identifies a broad range of plausible futures rather than a single bet.

Across consistent climate pathways, the potential use of h2 varies widely, roughly 600 to 3,200 TWh per year by mid-century. Green h2 produced from renewable electricity consistently emerges as the long-run, system-optimal option under EU targets and stricter pathways. The work also validates hydrogen’s flexibility value, with an emphasis on the short-term system benefits of Power-to-X. Finally, it offers insights on how European h2 markets may form and evolve as electricity, gas and hydrogen networks expand and connect regions.

The PhD study was completed at Department of Mechanical and Production Engineering (MPE), Faculty of Technical Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Tuesday, 11 November 2025 at 13:00
Place: Building 5335, room 091, Nygaard, Helsingforsgade 12 , 8200 Aarhus N
Title of PhD thesis: Systemic Perspectives on Hydrogen in Europe's Renewable Transition
Contact information: Zhiyuan Xie, e-mail: zyx@mpe.au.dk, tel.: +45 50180086
Members of the assessment committee:
Professor Bernd Möller, Department of Sustainable Energy and Development, Europa-Universität Flensburg, Germany
Senior Researcher Shi You, Department of Wind and Energy Systems, DTU, Denmark
Associate Professor Mahdi Abkar (chair), Department of Mechanical and Production Engineering, Aarhus University, Denmark
Main supervisor: Associate Professor Gorm Bruun Andresen, Department of Mechanical and Production Engineering, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS, Ny Munkegade 120, building 1521, 8000 Aarhus C.