Probabilistic Design Methods for Wind Turbines," has been officially released.

Recently, the International Electrotechnical Commission's Technical Committee on Wind Energy Generation Systems (IEC/TC 88) officially released IEC TS 61400-9: 2025, "Wind energy generation systems-Part 9: Probabilistic design measures for wind turbines."

Currently, the industry generally adopts a deterministic design approach when designing wind turbines. This approach ensures design safety by introducing a safety factor and verifying site adaptability in combination with external environmental conditions such as wind level. However, its design process is difficult to target specific scenarios and cannot fully utilize specific test data, specific site measurements, and external conditions for analysis. Therefore, it is difficult to effectively balance the cost and reliability redundancy of structures and mechanical components in long-term operation. In contrast, probabilistic design methods can provide a more scientific assessment of the structural and mechanical integrity of wind turbines by obtaining more accurate operating conditions, load, and resistance uncertainty data than assumed conditions, while also offering significant cost-effectiveness advantages.

IEC TS 61400-9:2025 specifies the minimum requirements for probabilistic design methods to ensure the structural and mechanical integrity of wind turbines. By comprehensively considering uncertainties such as material properties, environmental conditions, design models, and the degree of verification, it provides applicable methods and requirements for full probabilistic design. Furthermore, it covers provisions for semi-probabilistic design, including reliability-based partial safety factor calibration and assessment methods for existing wind turbines.

IEC TS 61400-9:2025 quantifies uncertainties by modeling external conditions (wind, earthquake, grid conditions, etc.), loads (extreme loads, fatigue loads, etc.), and structural resistance, constructing limit state equations, calculating reliability, and calibrating designs. This document is based on ISO 2394, "General Principles of Structural Reliability," and expands upon the "Calibration of Structural Material Safety Factors and Test-Assisted Structural Design" document, mentioned in the informative Annex K of IEC 61400-1:2019, "Wind Energy Generation Systems — Part 1: Design Requirements," addressing practical gaps.

The release of IEC TS 61400-9: 2025 will provide solid support for the safe and efficient operation of wind power equipment, reduce the cost per kilowatt-hour, and promote the healthy and efficient development of the wind power industry.