## 2 Description of PV-Powered Energy Island Structure  
EIs provide local, sustainable, and independent solutions for energy production with today's technology, thereby reducing reliance on the central grid. Typically constructed using RESs tailored for a specific region or community, these structures generate energy by harnessing DERs, such as wind, solar, and biomass. The primary benefits of EIs include energy independence, reliability, and the ability to function autonomously from the grid.  
These systems enhance energy supply security by supplying a consistent energy source unaffected by disruptions in the central energy infrastructure. Additionally, they mitigate economic and political risks by minimizing external dependencies through local energy generation. Furthermore, they foster a sustainable economy by lowering energy costs and leveraging renewable resources.  
Aligned with the European Union's zero-emission goals, EIs are vital in reducing carbon emissions by decreasing fossil fuel usage. Local energy production lessens the carbon footprint, enhances air quality, and promotes environmental sustainability. Moreover, it strengthens system reliability by providing flexibility and resilience in energy supply during extreme weather events exacerbated by climate change [37].  
Furthermore, EIs can incorporate innovative technologies, such as smart grid applications, electric vehicle infrastructure, energy storage systems, and green hydrogen production. Particularly with the advancement of hydrogen technologies, EIs represent a significant engineering solution for green hydrogen production and storage. These systems can also serve as testing and research and development (R&D) areas for chemical-electrochemical energy storage, demand management, and next-generation grid technologies.  
Lastly, EIs diminish fossil fuel dependence and deliver a more predictable and stable pricing advantage against energy market fluctuations. This way, they are less impacted by price changes associated with energy arbitrage processes, providing long-term economic stability.  
A thorough analysis of local meteorological and geographical data is necessary to determine whether an EI will be more efficient in terms of solar or wind energy. In summary, wind potential is generally higher in offshore EIs due to more consistent wind speeds over open seas. For mid-latitude, wind and solar energy potential can vary by season. In contrast, in tropical island regions, solar energy potential is predominantly higher because of abundant sunlight throughout the year onshore land-based EIs. However, in this study, from a general perspective, solar energy potential is typically higher in onshore land-basedEIs, while wind energy tends to dominate in offshore EIs. A solar-based, i.e., PV-powered EI case study is conducted, which is convenient for the Middle East, North Africa, Southern Europe, Mexico, and the inland regions of Australia.  
As illustrated in Figure 1, offshore DERs, such as wind turbines and solar panels, are typically connected to the land power system through submarine DC cables because of the capacitive charging effect of AC cables. In this setup, the voltage source converter (VSC) also converts DC power for local loads and the land AC system. This process involves DC transmission systems and power electronics interfaces.