Modelling analysis of maintenance logistics optimization for a floating wind park: A case study for Utsira Nord

The global society is part of a climate challenge that requires the development of will, understanding and technology. The United Nations has given the climate challenge its sustainability goal, saying, "Goal 13: Take urgent action to combat climate change and its impacts" [1]. There will not be sufficiently developed energy production today in the context of future electrification of the Norwegian everyday life and industry. Norway needs to invest in more green energy production not to become an import nation of energy, but; an export nation. On June 12th, 2020, the Utsira Nord area was opened by the Government by royal decree for energy production from floating offshore wind [2]. By taking a closer look at the well-known concept of Operating expenditures, one can see clear advantages and challenges related to floating offshore wind [3]. It shows how important it is to optimise the maintenance strategy for the industry, and this is the basis for this thesis. There are many logistics solutions, and many factors influencing the choice that is hard to know beforehand. Therefore, it will depend on each wind farm to decide the best alternative to provide maintenance services. Hence, this thesis aims to investigate the following questions: • How to utilize modelling and simulation method for selection of optimal maintenance logistics strategy for a wind farm at Utsira Nord • What will be an optimal maintenance logistics strategy for an imaginary Utsira Nord wind farm, seen from cost-benefit perspective and emission perspective A case study has been carried out based on an imaginary wind farm at Utsira Nord to answer the research questions. Shoreline software is used to create simulations, and analyses potential technical solutions. The research is executed in the following steps: (1) extract stakeholder requirements and acceptance criteria and define the purpose of the simulation model, (2) systems analysis of the wind park, maintenance program and logistic vessels, (3) collect and extract failure and maintenance data from existing offshore wind parks, (4) collect technical and economic data for several logistic maintenance vessels, (5) design and prepare the simulation cases, (6) perform the simulation cases and visualise the results, (7) verification and validation, including sensitivity analysis and (8) evaluate and select the most optimal logistic vessel alternative based on cost/availability and emissions When it comes to the most optimal vessel for the case wind park, the result clearly shows that the service operation vessel provides more benefits in terms of overall grading for cost/availability and emissions. It comes out far better than the crew transfer vessel because of the sensitivity associated with the maximum wave height for this vessel. This causes a significantly higher downtime for the wind farm, and the analysis shows that the case can increase its turnover by € 13,844,000 by using a service operation vessel in favour of a crew transfer vessel concerning lost production. The method used to carry out the analysis and simulation can be used as a starting point to provide the most optimal maintenance logistics strategy for each park. It can be common service operation vessel for several parks within the same field, several crew transfer vessels or make use of other logistical possibilities such as helicopters