Composing Vessel Fleets for Maintenance at Offshore Wind Farms by Solving a Dual-Level Stochastic Programming Problem Using GRASP

Background: Dual-level stochastic programming is a technique that allows modelling uncertainty at two different levels, even when the time granularity differs vastly between levels. In this paper we study problem of determining optimal fleet size and mix vessels performing maintenance operations offshore wind farms. strategic planning spans decades, while operational performed on day-to-day basis. Since level must somehow be taken into account making plans, since present both dual-level suitable. Methods: We heuristic solution method for based greedy randomized adaptive search procedure (GRASP). To evaluate costs given fleet, novel deployment (FDH) embedded GRASP. Results: Computational experiments show FDH produces near solutions to problem. Comparing GRASP exact methods, it small instances, significantly improving primal larger where methods do not converge. Conclusions: The proposed suitable solving realistic in less than 2 h.