There are currently some 23,000 wind turbines installed in Germany (as of late 2012). More than 70 percent of these are at least six years old. Most of these systems still operate with a rotor blade profile which was developed for the aircraft industry. Recent developments indicate that with an improvement of the system rotor’s aerodynamic qualities, substantial increases in yield may be achieved with the same rotor surface space. These findings have been incorporated into the design and construction of new rotor blades. The first phase of a project at Deutsche WindGuard Engineering GmbH, Bremerhaven, demonstrated an additional option: it is fundamentally possible to modify old rotor blades during the maintenance process in such a manner that they can produce a higher energy yield, without any related increase in noise emissions. The modifications involve minor structural alterations to the rotor blades such as the addition of spoilers, turbulators and similar devices. The goal of the second project phase is the elimination of the need for rotor blade disassembly, and approval of the corresponding construction elements.
