Cold start-up testing of +6MW offshore wind turbine gearbox

Wind power is the energy of the future, but wind turbines must be reliable even under extreme weather conditions. To that end, Sirris's OWI-Lab tested ZF Wind Power’s 80-ton gearboxes in its unique large climatic test chamber based in the port of Antwerp.

OWI Lab – the Belgian RD&I center for wind power – is a spearhead within the Sustainability expertise domain at Sirris. Reliable wind turbines have a direct impact on both energy output and operating costs. That means that testing critical components is very important. ZF Wind Power  delivers gearboxes for more than 2,000 wind turbines per year, 49GW of wind energy capacity worldwide uses components supplied by this Flemish world player. The company is also a leader in developing and manufacturing very large wind turbine gearboxes (> 6 MW) used for the offshore wind turbine industry. A prototype of this gearbox was tested in OWI-Lab's large climatic test chamber to comply with moderate cold and hot environments. Martijn Roozendaal, OWI-Lab’s test technician, is proud of this test: “This was the first test for offshore wind turbines of this size in our climate chamber. Previously, we mainly tested onshore gearboxes which are in the range of 20-40 ton.”

Unique large climatic test chamber for heavy machinery

The OWI-Lab took the challenge and tested the absolute state-of-the-art of what will be installed in the North Sea: a gearbox weighing nearly 80 tons, capable of generating 6.15MW. The component was tested at temperatures of -30 °C and 0 °C using the OWI-Lab mobile cold start-up test bench and data acquisition systems which can be moved into one of Europe’s largest climatic test chambers.

The specifications of the mobile no-load test bench are:

  • 5m x 4.5m test space
  • Inclinable drive unit (angle nacelle)
  • 10 kNm break- away torque possible
  • Max. 150 tons components
  • Torque sensor included


For ZF Wind Power, testing this prototype under extreme weather conditions is absolutely necessary. Wind turbines keep getting bigger and so it is increasingly difficult to find appropriate testing facilities that can handle the large dimensions and weight. Roozendaal: “Our unique large climate chamber was the ideal solution for these kinds of tests, also our additional services apart from the climate chamber itself make the difference in such big projects”. Also the location of the test facility (Port of Antwerp - Breakbulk terminal Zuid-Natie) and the ability to use large cranes and lifting tools to handle such large test specimens is a merit.

The Sirris environmental test chamber can offer temperatures from -60°C to +60°C with or without 10%RH -95%RH humidity conditions and/or Solar IR heat, reproducing the extreme conditions under which the wind turbines sometimes have to operate in locations like Offshore, Arctic, Inner Mongolia, Middle East, Scandinavia, Canada, India,… The multi-MW gearboxes of ZF are now ready for duty in the North Sea!

Interested in the topic environmental testing and cold climate compliance for wind power systems? Take contact with our expert