The global energy landscape is undergoing a significant transformation, marked by the increasing fragility of conventional energy systems and a decisive shift towards electrification to meet climate objectives. This transition elevates energy security and resilience to core priorities for governments and industries. Offshore artificial energy islands are emerging as pivotal strategic infrastructures, particularly in regions like the North Sea, designed to expand renewable energy capacity, alleviate grid congestion, and facilitate power exchange, thereby supporting overarching climate and energy security goals. This thesis investigates how integrating multiple functionalities, specifically energy generation and port logistics, within a single offshore island could enhance financial feasibility. The central research problem addresses how to assess the techno-economic viability of such multi-functional offshore islands, with the Princess Elisabeth Island (PEI) in the Belgian North Sea serving as a representative case study. Current assessment methodologies often fall short in comprehensively evaluating the intertwined financial and operational aspects of combining distinct energy and port functionalities on a unified offshore platform, creating a notable research gap. The primary objective of this research is, therefore, to develop and apply a standardized, transparent Techno-Economic Analysis (TEA) framework tailored for these complex, integrated systems.

The methodological approach is rooted in a TEA framework, systematically applied to the PEI case. This involves a physical breakdown of systems, detailed financial analysis including CAPEX, OPEX, revenue projections, and cash flow modeling, and performance analysis using key metrics such as Levelized Cost of Energy (LCOE), Net Present Value (NPV), and payback periods. The PEI project, planned for 3.5 GW of offshore wind connected via an artificial island housing AC and HVDC substations, formed the initial focus. The base case analysis for PEI as a standalone wind energy hub revealed significant financial challenges: amedian LCOE of 224 =C/MWh, substantially exceeding recent offshore wind strike prices, and a consistently negative NPV. This financial vulnerability is largely attributed to the dramatic increase in transmission infrastructure costs, which now account for nearly 50% of the total project CAPEX, a sharp rise from approximately 18% in 2020. Sensitivity analyses indicated that the LCOE is highly susceptible to project delays, ranging from 200 to 260 =C/MWh, and noted a cooling investor appetite in the European offshore wind sector. Enhanced base case considerations for the wind system showed that an AC-only configuration could reduce the LCOE to 182 =C/MWh, while incorporating HVDC as an interconnector, despite potential arbitrage revenues, increased the LCOE to 237 =C/MWh, illustrating a trade-off between strategic energy security benefits and immediate financial viability...