Risk-based Optimization of Inspection and Maintenance of Offshore Wind Turbine Support Structures via Probabilistic Cost Modeling
Source: BAM
This paper presents a novel probabilistic cost modeling framework that enables the risk-based optimization of inspection and maintenance (I&M) strategies for offshore wind turbine support structures. Risk-based I&M planning plays a key role in the lifetime extension of offshore wind farms. While existing approaches rely on deterministic values and neglect uncertainties, this approach enables risk-based optimization of I&M strategies under cost uncertainty. The framework introduces a parametric cost model incorporating probabilistic distributions for key cost components—inspection campaigns, structural repairs, and vessel logistics—derived from expert input and literature data. This model enables the quantification of probabilistic I&M costs at the component, structural system, and wind farm levels.
A variance-based sensitivity analysis identifies the most significant cost drivers. At the component level, campaign and engineering costs have the greatest influence, while at the structural system and wind farm levels, vessel costs per shift dominate overall I&M costs.
The framework is applied in a numerical case study using a representative offshore steel-frame structure to compare two risk-based I&M strategies: a baseline (no-action) approach and a heuristic strategy with optimized decision rules for inspection and maintenance activities. The case study demonstrates that I&M costs can be treated as deterministic expected values in risk-based analyses if they are included in the optimization on a linear basis. The expected I&M costs at the structural system level are primarily governed by the number of campaigns, the number of components involved, and the expected campaign, engineering, and operational costs. These costs can be normalized and used in risk-based optimizations of I&M strategies at the structural system level.
Future work will focus on developing similar deterministic (normalized) cost models for risk-based I&M planning at wind farm level.
Probabilistic cost modeling as a basis for optimizing inspection and maintenance of turbine support structures in offshore wind farms
Muhammad Farhan, Ronald Schneider, Sebastian Thöns, and Max Gündel
Wind Energy Science, Volume 10, issue 2, 2025