BAM is researching the safe operation of offshore wind turbines in the project "Service life extension and service loading fatigue of wind turbines" (LeBeWind). The research is focusing on methods for reliable detection, localisation and evaluation of damage with the aim of ensuring service loading fatigue and extending the service life of wind turbines. The project team aims to develop damage detection and repair concepts that are efficient at sea. Therefore, BAM integrates its research competencies in civil engineering, materials engineering and materials science. Subprojects are devoted to the repair of rotor blades, corrosion protection by coatings, the connection of steel pipes by special mortar, and service loading fatigue of the drive train. Overarching topics are the determination and evaulation of current conditions, in particular non-destructive testing as well as prevention of possible damage.