Wind turbine tower collapse cases: a historical overview

Wind turbines are conceived, designed and operated to interact with the environment, including through extreme events. However, engineering malpractices combined with human or mechanical errors and defects of constituent members and materials, still result in hundreds of structural collapse cases annually. It seems, therefore, necessary to reflect on factual wind turbine performance against the target performance. The present paper summarises the most severe tubular wind tower collapse incidents recorded over the past four decades, provides an account of the damage and discusses the respective potential causes. The investigation indicates that, although accidental load induced by typhoons and storms is the most usual reason of failure, fatal events concentrate at either early or late stage of the designed service life. Unexpected load conditions seemed to derive from defective blade positioning or braking, which in turn over-stress areas of transition such as joints and openings. However, a critical examination of design standards suggests that, in general, wind turbine towers as designed and built nowadays are stable and reliable. Hence, the chain relationship determined by the design, manufacturing, construction, operation and maintenance, needs enhancement and further cohesion, at the time that our understanding of and adaptation to extreme events continues to develop.