Floating modular energy islands (FMEIs) are modular, interconnected floating structures designed to collectively produce, store, convert, and transport renewable energy. This review aims to establish a foundation for developing innovative approaches to sustainably harness multi-energy sources in offshore environments. It leverages existing technological expertise while exploring new solutions to address specific challenges associated with FMEIs. The review initially presents existing technologies for floating energy structures and assesses their applicability to FMEI. The structural materials that could be utilised for the construction of a floating energy island are subsequently reviewed. Next, the offshore construction technologies suitable for FMEI are reviewed. Finally, studies on the life cycle assessment of hybrid energy systems are examined, highlighting the environmental advantages of integrating multiple renewable energy sources, thereby underscoring the potential of FMEIs.

Floating Modular Energy Islands (FMEIs) are modular floating structures which combine different types of renewable energy production systems. FMEIs are still at their conceptual phase; however, they promise good potential for using the limited ocean space in an efficient way to produce renewable energy. Since those systems would have different components and related materials, offshore construction/installation work and systems to transport generated energy to land, their environmental sustainability is an important aspect to evaluate, as for other existing marine renewable energy systems. Life cycle assessment (LCA) is a scientific, standardized and quantitative methodology for the evaluation of environmental sustainability and it is accepted to be compatible for the evaluation of marine renewable energy systems. This study focuses on previous applications of LCA on various marine renewable energy systems, which have the potential of being a component of a floating modular energy island. With this aim, a brief literature review on possible different components of energy islands is conducted. Offshore wind energy, tidal energy systems, wave energy converters, floating solar energy and hydrogen energy are selected to be reviewed in the study. For the literature review, a common literature screening methodology is developed with a similar keyword group except the marine renewable energy type considered. Selected papers in each energy type production technology are reviewed with reference to the main phases of a LCA study: Goal and Scope Definition; Life Cycle Inventory (LCI); Life Cycle Impact Assessment (LCIA) and Interpretation. Under each subtitle, the approaches followed are assessed covering the important aspects, methodology/criteria considered, and challenges encountered. By this way, it is aimed to generate knowledge on the LCA methodology as a guideline for the FMEIs.

Floating Modular Energy Islands (FMEIs) are modularized, interconnected floating structures that function together to produce, store, possibly convert and transport renewable energy. Recent technological advancements in the offshore energy sector indicate that the concept of floating offshore energy islands has the potential to become more cost-effective and more widespread than previously anticipated. This review is specifically meant as a basis for the development of new approaches to the sustainable exploitation of multi-energy sources in the offshore environment leveraging the know-how of existing technologies and, at the same time, exploring new solutions for the specific challenges of FMEIs. The paper critically analyzes the current state of data-driven approaches and structural health monitoring techniques in the offshore energy sector. It also covers topics such as met-ocean data, load estimation, platform dynamics, coupling actions, nonlinear dynamics of mooring lines, modelling considerations, and control of electrical subsystems. It is believed that this systematic and multidisciplinary review will facilitate synergies and further enhance research and development of offshore renewable energies.