Sönke Siegfriedsen founded the company aerodyn in 1983, which has now been active as an independent engineering and consulting office for wind turbines for 40 years. Due to these early activities, Sönke Siegfriedsen is regarded as a pioneer in the wind energy industry. As early as 1984, a year after being founded, aerodyn undertook groundbreaking work with the first complete development of a 25 kW wind turbine and its testing in the test field on the North Sea island of Pellworm. This initial project delivered well-founded knowledge about aerodynamic behaviour, mechanical loads and turbine control engineering. Over the following 40 years aerodyn has developed nearly 30 types of wind turbines, from 5 to 10.000 kW, and has worked for companies around the world. Wind turbines designed from aerodyn, or in whose development aerodyn played a significant role, are producing energy on all five continents, with more than 50.000 turbines. Without any doubt, this figure sets aerodyn apart as the world’s leading independent engineering firm for the development of complete wind turbines and single components – and it is clear that many innovative concepts and developments from aerodyn have influenced the current state of the art. Since 2014 aerodyn drives the floating offshore wind technology with its nezzy developments. The work carried out by aerodyn’s skilled engineering team includes the development of innovative wind turbine concepts, structural dynamics and load calculations, component design, component optimization, aerodynamic and structural rotor blade design, finite element analysis for cast, welded and fiber composite components, as well as the compilation of complete documentation for manufacturing and certification. Thus, aerodyn offers wind turbine and component manufacturers in all fields of wind-energy engineering comprehensive know-how and services, which allow them to produce even more reliable, better-performing and lower-priced wind turbines. Innovative concept developments are offered on a license base or as technology and know how transfer to increases the local content of onshore, offshore and floating projects.