Limiting global warming to 1.5°C is urgent, as highlighted by IPCC and IEA reports aiming for net zero emissions by 2050. Wind energy, particularly offshore, offers significant potential for renewable energy capacity expansion. Although offshore installations are limited to shallow waters using monopiles, deeper waters with higher wind speeds require larger turbines. This transition to deeper waters and larger turbines is challenging and requires continuous development and innovation. Floating wind turbines show promise for overcoming these challenges, but further improvements are needed to scale up floating wind farms and reduce installation costs for profitability. Bluewater Energy Services is a company actively exploring solutions to improve the installation method of floating wind turbines with the Transport and Installation Frame. In addition to the market gap for the installation of floating wind turbines, there are also opportunities in the development of bottom-fixed wind for larger wind turbines and greater water depths. Therefore, the goal of Bluewater is to design a frame for the transport and installation of both bottom-fixed and floating wind to increase profitability.

The aim of this research project is to assess the feasibility of the Transport and Installation Frame for bottom-fixed wind. The research question has been answered using a systematic design methodology. Initially, information was collected, research questions were formulated and starting points were established through a literature study. The first phase, system analysis, outlined the transport and installation methodology and defined the design criteria. Subsequently, the design of the bottom-fixed structure, which could be installed using the frame was explored. Finally, the limitations of the transport and installation methodology were examined, particularly focusing on the maximum angle of heel, natural period, and the weather window.

Towards the conclusion of the thesis, an evaluation is presented regarding the feasibility of the frame for bottom-fixed wind. This includes an initial design for the bottom-fixed structure and the transport and installation methodology, based on the integrated installation method for a 15 MW wind turbine. The transport and installation methodology in this thesis focuses on the compression principle. In which the Transport and Installation Frame remains at the waterline and the bottom-fixed structure is lowered to the seabed at 80 meters by pushing it with spud piles down. This study identifies critical stages and associated issues related to static stability, maximum heeling angles, deck or edge immersion, spud pile strength, seabed placement, and the natural periods in heave and pitch.

The results of the design research indicate that, within the identified limitations, there are no significant unresolved issues affecting the feasibility of the transport and installation frame for bottom-fixed wind. This conclusion is based on analyses focused on static and strength analysis. To assess the technical feasibility, it is recommended that the specifications of the weather window be refined, static optimisation be performed, and critical issues related to dynamic behavior be addressed, specifically during seabed placement and dynamic responses to external forces. To further develop this project and explore the profitability, it is recommended to obtain an overview of the specific location, costs, and installation time.

Floating Offshore Wind Turbines (FOWTs) have emerged as a promising technology for generating clean energy in deep water locations. Bluewater Energy Services proposes a Tension Leg Platform (TLP) as the floating support structure. An effective Structural Health Monitoring (SHM) system (of which there are various types) can facilitate timely interventions and optimize inspection and maintenance activities by providing continuous insights into their structural condition. Fatigue damage is especially critical for the support structures of FOWTs, as they are subject to cyclic loads that can cause structural damage.

This research proposes a fatigue monitoring system for a TLP supporting FOWTs. The methodology used is Modal Decomposition and Expansion (MDE). Due to the complexity of the studied structure in terms of structural dynamics, MDE is selected for its ability to capture dynamic behaviour. The main objective of the fatigue monitoring system is to perform the full-field strain estimation based on a limited number of sensors. This could also allow for the verification of the design considerations. With the presented response reconstruction approach, the stress in the locations prone to fatigue of the platform can be monitored and therefore, enabling estimation of the remaining lifetime of the structure and optimize maintenance planning.

Different analytical and numerical models are used in this investigation. The application of MDE in a simple structure (i.e. a cantilever beam) is first assessed to verify the performance and to gain insights of the methodology. Later, MDE is applied to a simplified TLP model to validate the response reconstruction approach and demonstrate its applicability for TLP-like structures.

Finally, a FOWT numerical model is used to design the fatigue monitoring system. The proposed system consists of two layouts of two strain gauges in the upper column of the TLP, and two layouts of two strain gauges on each pontoon. This system can provide full-field strain estimations with over 88.9% accuracy and predict fatigue damage accumulation with errors of less than 0.01%. Also, the system presented in this thesis only predicts global responses. However, the fatigue of the structure is also influenced by local structural responses due to sea pressures. Therefore, future research to include local effects in the predictions is recommended.