Floating photovoltaic (FPV) systems offer a way to expand solar power offshore and can potentially be integrated with existing wind farms to diversify energy mix. A key challenge is the design of the dynamic power cable (DPC) that transports electricity from floating units to the seabed while subjected to waves, currents, and wind. This thesis evaluates the structural behaviour and installation feasibility of DPCs for a lightweight FPV concept (Solar@Sea III developed by Bluewater Energy Services) in shallow North Sea conditions at 20 m and 35 m water depth.

In this study, time-domain finite-element simulations in OrcaFlex are used under Ultimate Limit State (ULS) conditions. Two configurations, catenary and lazy-wave, are compared. A parametric study varies hang-off point (HOP) angle, bend-stiffener dimensions, and buoyancy-section characteristics. Decoupled and coupled analyses then assess three integration points within the FPV system: the floater, a corner buoy, and the transverse line. Performance is measured by peak curvature, tension, and seabed clearance.

Curvature is the governing design constraint; tensions remain well below strength limits across cases. Standard bend stiffeners reduce end-region curvature but are not sufficient alone. Combined HOP-angle adjustments and stiffer or longer bend stiffeners are most effective in 20 m water depth. At 35 m, curvature hotspots move away from the ends, and benefits from local end-point adjustments decrease. Lazy-wave configurations increasingly help at 35 m by lowering curvature, distributing it along the cable’s length, and stabilising tensions. At 20 m, however, they provide limited seabed clearance (often <2 m), which is operationally risky without accurate buoyancy calibration and regular inspection.

System integration strongly influences performance. Among the tested connection points, the corner buoy offers the best balance of mechanical response and practicality, acting as an accessible hub that reduces motions at the HOP and eases installation and maintenance. For 20 m depth, a catenary cable connected at the corner buoy is the most reliable and feasible option. At 35 m, the lazy-wave configuration becomes more attractive due to improved curvature and tension margins, though with higher installation complexity.

Overall, reliable DPC design for offshore FPV requires an integrated approach that couples lay-out configuration, connection strategy, installation, and operations from the outset. This initial analysis indicates that a catenary DPC configuration is feasible for lightweight FPV systems in the North Sea, but an increase in cable bending stiffness is preferred to improve curvature control and design margins.

This study investigates the development of sustainable offshore fish farms in Sisal, Yucatán. Local fishermen face seasonal restrictions on fishing due to environmental regulations. Given the socioeconomic dependence of the region on fishing, the community of Sisal has been experiencing increasing instability of livelihoods. Offshore fish farming has emerged as a potential solution to this challenge, offering an alternative income source outside the traditional fishing season. However, previous industrial attempts to introduce fish cages failed due to a lack of local engagement and inadequate design, leaving Sisal residents sceptical. To address these past issues, this research seeks to design affordable, durable, and locally accepted fish cages that meet the unique environmental and social conditions of Sisal. Valuable insights were gained from fish farms in Celestún, a nearby village with successful communityled offshore aquaculture. Celestún’s approach, using smaller, manageable, and collectively funded cage, has proven to be both economically and socially beneficial. This makes it a relevant model for Sisal, though Sisal’s steeper coastal gradients and greater exposure to maritime forces require adaptations to ensure durability and long-term success. The research follows a multi-step methodology, beginning with interviews with local fishermen and experts to understand their needs and preferences for cage design and placement. These insights were integrated with environmental data on wave height, wave period, and current speeds collected through field measurements and the ERA5 reanalysis dataset. Using this input, an Multi-Criteria-Analysis (MCA) was conducted to determine the optimal offshore location for the fish farms. To determine the structural needs for fish cages under Sisal’s conditions, the research used ProteusDS simulation software [14] to model various cage dimensions, mooring tensions, and layout configurations. Key findings indicate that positioning the fish farms at 8 kilometres offshore is optimal for long term success. At closer distances to the coast, water quality decreases, resulting in higher maintenance requirements and compromised fish health. Greater distances increase installation costs and operational costs due to higher fuel demands. With the optimal location established, the research follows with the determination of key design parameters essential for the structural integrity of the fish cages near Sisal. An extreme value analysis of an ERA5 dataset was performed to estimate the 20-year return level for the wave height, resulting in a design wave height of 4.19 metres. This value was adjusted for local conditions using a scaling factor derived from the comparison between local and ERA5 data, resulting in an adjusted design wave height of 3.40 metres. A power-law regression was then applied to establish the relationship between wave height and wave period, estimating a design wave period of approximately 8.01 seconds corresponding to the adjusted wave height. For the current analysis, the 95th percentile of current speeds was examined, determining a maximum design current speed of 0.50 m/s near the surface. Furthermore, analysis of wave and current directions revealed that extreme waves predominantly come from the north to north-east directions (340° to 20°), while the strongest currents flow toward 70° and 250°, indicating eastward and westward flows. The optimal cage design determined through simulations includes a cage diameter of 12 metres and a net depth of 4.7 metres to withstand Sisal’s environmental forces. Additionally, distinct mooring-tension configurations were tested in the ProteusDS software, including Concept 1 (a single-cage setup), Concept 2 (a two-cage configuration with four mooring anchors), and Concept 3 (a three-cage arrangement with three anchors). Each concept required specific anchor weights and dimensions to endure the high wave and current forces at this location. Orientation adjustments were also incorporated to reduce tension, aligning each cage setup with different wave and current directions, thereby optimizing structural reliability. Future fish cage designs should include adaptive anchoring and precise orientation to enhance stability and involve the local community for sustainable, long-term success. The study concludes that, to achieve long-term viability, fish cages in Sisal must be affordable, easy to maintain, and capable of withstanding local environmental conditions. Future recommendations include deepening community involvement, implementing enhanced safety and resilience measures, and refining cost analysis to foster broad acceptance among local fishermen. By ensuring that the fish cages are both economically viable and environmentally sustainable, this project aims to secure a stable income for Sisal’s fishing community, thereby improving their quality of life while reducing pressure on marine ecosystems