Improved Methodology of Weather Window Prediction for Offshore Operations Based on Probabilities of Operation Failure

Abstract

Abstract:The offshore wind industry is building and planning new wind farms further offshore due to increasing demand on sustainable energy production and already occupied prime resource locations closer to shore. Costs of operation and maintenance, transport and installation of offshore wind turbines already contribute significantly to the cost of produced electricity and will continue to increase, due to moving further offshore, if the current techniques of predicting offshore wind farm accessibility are to stay the same. The majority of offshore operations are carried out by specialized ships that must be hired for the duration of the operation. Therefore, offshore wind farm accessibility and costs of offshore activities are primarily driven by the expected number of operational hours offshore and waiting times for weather windows, suitable for offshore operations. Having more reliable weather window estimates would result in better wind farm accessibility predictions and, as a consequence, potentially reduce the cost of offshore wind energy. This paper presents an updated methodology of weather window prediction that uses physical offshore vessel and equipment responses to establish the expected probabilities of operation failure, which, in turn, can be compared to maximum allowable probability of failure to obtain weather windows suitable for operation. Two case studies were performed to evaluate the feasibility of the improved methodology, and the results indicated that it produced consistent and improved results. In fact, the updated methodology predicts 57% and 47% more operational hours during the test period when compared to standard alpha-factor and the original methodologies.

Decision Support Models for Operations and Maintenance for Offshore Wind Farms: A Review

“…He classifies the spare parts inventory management and the maintenance support organization (vessels, cranes, helicopters, personnel) as a tactical issue in offshore wind farm maintenance logistics. Gintautas and Sørensen [24] present constraints for both installation and O&M vessels given in the previous literature by Dinwoodie et al [44], Besnard et al [13], Nielsen and Sørensen [10], O'Connor et al [45], Van Bussel and Bierbooms [46], O'Connor et al [47], McMillan and Ault [48], Wu [49] and Ahn et al [50]. Raknes et al [25] consider two different vessel types-an accommodation vessel and a crew transfer vessel, in their analysis.…”

Economic Block Model Development for Mining Seafloor Massive Sulfides

“…An example of guidance for establishing weather operability criteria was proposed by DNV-GL in [48]. This guidance is a common standard within the marine industry and is used as a base for comparison of advanced techniques [49,50]. As described in the guidance, establishing the weather operability for an equipment or an operation includes the knowledge of the sequence of operations, failure mode and contingency scenarios [48] (Section 4 therein).…”

Use of Markov Decision Processes in the Evaluation of Corrective Maintenance Scheduling Policies for Offshore Wind Farms

“…Additionally, different policies can only be evaluated manually, by implementing each strategy individually in the model. Some exceptions to the dependency on Monte Carlo simulations are some newer approaches, using stochastic models [3] or genetic algorithms [4]. The influence of uncertainties on the optimal scheduling of corrective maintenance has been investigated for the repair time [5], and the weather forecast [3,6].…”