Floating Offshore Wind Turbine Installation, Operations and Maintenance (FOWT IO&M)

WHY

Floating offshore wind turbines are maturing and increasingly becoming a viable and attractive solution for offshore wind energy production. It is therefore important to get a better picture of the installation, operation and maintenance costs of the floating wind turbines. It is also important to gain more insight into the impact of maintenance on the availability of the turbines. In particular, the impact of different methods for major component replacement (MCR) is investigated.

Although floating turbines may not be installed in the Dutch North Sea due to the shallow waters, research hereafter is relevant to the Netherlands-based industry due to its vital role in developing and installing offshore wind farms. Both Dutch contractors and developers will benefit from the research. The contractors have a strong reputation in the installation of bottom-founded offshore wind turbines. The developers of offshore wind projects will benefit from the research because it allows them to better quantify the (financial) risks of floating wind.

WHAT

This project concerns desktop research involving knowledge institutes and the leading offshore wind stakeholders. In this study, we address time and cost-based operability, focusing in particular on the transportation, installation, and accessibility of the turbines. In addition, we include the necessity and feasibility of major component replacement in the analysis, whether it is more efficient to tow the turbine back to port or perform major component replacement in the field.

In the first step of the study, relevant information about floating wind is collected by conducting an extensive literature search and a stakeholder consultation. In a workshop, we share the results of the literature review and encourage stakeholders to share their operational experiences, challenges, and opportunities.

We evaluate the time and costs for maintenance activities using existing tools and methods from TNO, MARIN and industrial partners. The project aims to offer a pragmatic low-fidelity approach but still with sufficient reliability to capture relevant details of floating wind installation and maintenance activities. The failure rates and operational limits are particularly important for the evaluation.

Failure rate: To accurately predict the availability of floating wind turbines, it is essential to model maintenance needs adequately. We classify maintenance work as follows: unplanned maintenance, preventive or planned maintenance and condition-dependent maintenance. In consultation with the stakeholders, we determine the failure frequencies per maintenance category. Operational limits: to determine the accessibility of maintenance personnel, we use safe operational limits for personnel. We define the limits of human work from the literature and our in-house expertise. The operational limits are of great importance because they can limit the availability of maintenance work and should be considered when optimising the transfer equipment design.

EXPECTED RESULTS

This project involves a literature review, stakeholder consultation, quantitative analysis and dissemination of our methodology and findings to industry.

This project collects and summarises relevant information about transportation, installation and maintenance of floating offshore wind turbines.

Furthermore, the project develops a pragmatic methodology to determine the time and cost-based operability of floating offshore wind turbine transportation, installation and maintenance operations. The methodology is applied to evaluate the time and cost-based operability of a fictive, but realistic large-scale offshore wind farm development.

The time and cost-based operability of various major component replacement strategies will be studied, including transportation to port and in-field maintenance.

Consortium partners validate the outcomes, and the project team will compare the results with previous research on floating wind turbines, support vessels, and access systems. The current project’s outcomes are relevant and invaluable for the Netherlands-based developers, contractors and other parties active in the floating wind industry.