Wind machines and traditional Dutch windmills preceded electricity supply and were used for grinding grain. They were always attended, sometimes inhabited and, largely, manually controlled. They were integrated within the community, designed for frequent replacement of certain components
and efficiency was of little importance. Wind turbines have been in use since 1941. The function of a modern power-generating wind turbine is to generate high quality, network frequency electricity. There is information and advice on the non-destructive testing (NDT) of wind turbines in Europe
and internationally, but because mass production of wind turbines is fairly new, no manufacturing standards have been set yet. There is also a need for European standards, in the testing, certification and accreditation of turbines and components. The main objectives in this paper are to
review the current state of NDT of wind turbines at manufacture and in-service, and to establish the most promising NDT methods for detecting flaws of most concern.