Towards Closed-loop Maintenance Logistics for Offshore Wind Farms

Abstract

Europe’s offshore wind capacity is expected to reach 450 GW by 2050, meeting 30% of Europe’s electricity demand. With the increase of installed capacity, the costs invested in O&M will also increase significantly considering O&M cost is one of the biggest contributors to life cycle costs. The improvement of O&M management for offshore wind farms, especially maintenance logistics, represents a significant cost-reduction opportunity and will continue to be a primary factor in shaping the future development of the offshore wind sector. Recent research provides clear insights into maintenance logistics management, categorizing decisions into three levels, strategic, tactical, and operational. Maintenance strategies and resource organization are strategic and tactical decisions respectively, with a long lasting influence on offshore wind farms. With sensors and communication technologies, wind farm owners/operators and service providers can use the health information of wind farms to design maintenance strategies and organize maintenance resources, and utilize new data to update decisions to realize a closed-loop manner. Thus the research question of this thesis is how to improve the effectiveness of maintenance strategy and resource organization for offshore wind farms and move towards a closed-loop decision-making approach? In this thesis, an open-loop predictive opportunistic maintenance strategy utilizing predicted component failures and maintenance opportunities is developed first. Then, the influence of inaccuracy or uncertainty in model parameters is quantified on maintenance performance and strategies. The significance of different uncertainties is ranked, and suggestions are provided to cope with the uncertain decision-making environment. Next, the approaches are proposed to organize the primary maintenance resources, i.e., spare parts and service vessels, to support the implementation of the open-loop maintenance strategy in a cost-effective manner. Finally, the open-loop maintenance strategy develops towards a closed-loop maintenance strategy that is able to capture dynamic wind farm states and mitigate the influence of model parameter uncertainties, reducing more revenue losses than open-loop approaches. Overall, this thesis provides a series of approaches for offshore wind farm owners and operators and maintenance service providers to instruct the strategic and tactical maintenance logistics for offshore wind farms, showing the potential for improving the effectiveness and moving towards a closed-loop manner.