Siemens Energy has announced that it will test two 3.6MW wind turbines with direct drive (DD) technology at a site in west Denmark.

Siemens will subject the two DD wind turbines to comprehensive testing for a minimum of two years. The purpose of this project is to assess whether direct drive technology is competitive with geared machines for large turbines. One of the main objectives of the Siemens DD project is to establish if and for which turbine sizes direct drive machines are competitive with geared turbines. Siemens will equip the two DD test wind turbines with synchronous generators excited by permanent magnets. The test generators will be supplied by two different companies: One was developed by the Siemens Industry Sector and the other by Converteam. With a rotor diameter of 107 meters and a power rating of 3.6MW, the two test turbines are similar in design to the standard Siemens SWT-3.6-107 offshore machine. By selecting a proven technological basis for the test machines, Siemens will be able to use standard rotor blades, standard towers and many standard components from the 3.6MW series-produced machine. However, Siemens does not intend to use the configuration of the DD test turbines for future series production.