Optimal Decision Making for Life Extension for Wind Turbines

This paper presents how the decisions made in relation to life extension for wind turbines can be formulated as a Bayesian decision problem with decisions on analyses and inspections before the decision on whether to extend the lifetime. The paper presents an implementation where semi-probabilistic analyses are used to verify whether the fatigue life is sufficient for life extension, and where operational data can be exploited to reduce epistemic uncertainties for a more accurate prediction of the fatigue life. The optimal decision policies depends on the expected benefit of life extension, and there is a potential for making general recommendations to support wind turbine owners.