Assessing the life cycle risks of offshore wind turbines with suction bucket foundations

Abstract

The risk assessment of offshore wind turbines is increasingly significant due to the increase in accidents. However, the life cycle risk assessment of suction bucket foundations is challenging owing to the limited number of installations and lack of relevant data. In this study, an improved fuzzy fault tree analysis method (IFFTA) based on the analytic hierarchy process (AHP) is proposed to evaluate the life cycle risks of offshore wind turbines (OWTs) with suction bucket foundations. First, a fault tree analysis (FTA) model was employed to establish a risk index system for the suction bucket foundation. Then, the fuzzy set theory was performed to obtain the crisp probabilities of basic events, and AHP was adopted to determine the importance weights of basic events. Finally, the risk occurrence probability and risk level of OWTs with suction bucket foundations were determined, and the critical risk factors were identified. A case study demonstrated the applicability of the proposed method. The results show that the risk occurrence probabilities of OWTs with suction bucket foundations in the construction, service, survey and design periods are 3.25e-03, 4.47e-03, and 5.48e-04, respectively, and the corresponding risk levels according to DNV-RP-F107, one of the most authoritative recommended practices in the field of ocean engineering, are high, high, and medium respectively. The proposed method overcomes the limitations of traditional methods and provides some risk reduction measures for engineering references. • Improved fuzzy fault tree analysis is developed for the life cycle risk assessment of offshore wind turbines. • The risk factors of offshore wind turbines with suction bucket foundations are identified. • The critical risk factors are identified, and several risk reduction measures are recommended. • The economic advantages of offshore wind turbines with suction bucket foundations are studied.