Multi-energy systems: optimisation, coordination, offshore applications and techno-economic assessment

Ma, Miaorui (2026) Multi-energy systems: optimisation, coordination, offshore applications and techno-economic assessment. PhD thesis, University of Glasgow.

Abstract

The increasing penetration of renewable energy presents significant challenges to modern power systems due to the intermittency, uncertainty, and vulnerability to extreme weather conditions. Existing studies often address uncertainty modelling, system coordination, and offshore energy applications separately, with limited consideration of integrated optimisation frameworks that simultaneously improve operational flexibility, renewable energy utilisation, and long-term technoeconomic performance under realistic environmental conditions. This thesis develops novel frameworks for modelling, optimisation, and techno-economic assessment of integrated multi-energy systems, with a focus on selected potential operational scenarios of microgrids, transmission–distribution coordination, and offshore energy islands, which are all tuned for the challenging renewable energy utilisation.

First, a multi-energy microgrid operational framework is proposed to integrate combined heat and power with renewable energy resources. A data-driven distributionally robust optimisation approach is adopted to address uncertainties in generation and demand. By combining day-ahead hourly scheduling with intra-day 15-minute dispatch, the framework enhances renewable utilisation, reduces operational costs, and achieves measurable carbon emission reduction by 10.6%.

Second, a coordinated optimisation model for transmission and distribution networks is developed, incorporating hydrogen-based energy storage. A mixed-integer linear programming formulation captures both physical characteristics and economic interactions, demonstrating improved flexibility and increased system revenues, which is 9.3% higher compared with uncoordinated cases. This coordination allows distributed energy resources contributing to higher-level system operations.

Third, the thesis investigates the techno-economic performance of offshore energy islands under coupled wind–wave conditions. High-fidelity OPENFAST simulations are applied to analyse power output and hydrogen production under varying wind speeds, revealing the sensitivity of revenues to extreme environmental conditions. Furthermore, a surrogate modelling approach based on Kriging is developed for floating energy islands, enabling efficient assessment of power generation and fatigue damage. Results highlight that optimal site selection can increase life-cycle profits by over 40%, demonstrating the significant impact of coupled environmental conditions on the techno-economic performance of floating offshore energy islands.

Overall, this thesis contributes knowledge in: (1) advancing the optimisation of multi-energy microgrids subject to uncertainties, (2) proposing a coordinated transmission–distribution framework with hydrogen integration, and (3) developing techno-economic methodologies for offshore and floating energy islands. The findings provide theoretical and practical insights for the transition toward low-carbon, reliable, and sustainable energy systems.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: T Technology > T Technology (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Yang, Professor Jin and Li, Dr. Guanchen
• Date of Award: 2026
• Depositing User: Theses Team
• Unique ID: glathesis:2026-85993
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 02 Jun 2026 14:49
• Last Modified: 02 Jun 2026 14:50
• Thesis DOI: 10.5525/gla.thesis.85993
• URI: https://theses.gla.ac.uk/id/eprint/85993

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