Adwen and Winergy worked in closer cooperation to develop the gearbox for Adwen’s AD 8-180 offshore wind turbine. With an input torque of close to 10,000 kilonewton-meters (kNm) and a weight of 86 tonnes. it is the largest wind-turbine gearbox ever built in the world. With an input torque of close to 10,000 kilonewton-meters and a weight of 86 tonnes it is the largest wind-turbine gearbox ever built in the world. Winergy’s gearbox was designed exclusively for the AD 8-180 wind turbine. It is part of a medium-speed drivetrain concept that will considerably help reduce the levelized cost of energy (LCOE) on Adwen’s new offshore giant. At 180 meters, the AD 8-180 boasts the world’s largest-diameter rotor. In combination with a nominal electrical power of 8 MW the gearbox attains an input torque of close to 10,000 kNm – a value never before equaled. This 70% increase in torque capacity was achieved with only a 20% weight increase compared to other gearboxes used in offshore wind turbines larger than 6 MW. The two-stage-planetary gearbox is directly connected to a medium-speed generator via a flange connection. Thanks to the choice of a medium-speed gearbox concept and leveraging proven technologies well known by both companies, Adwen and Winergy can successfully maximize the efficiency of the drivetrain, while cutting the cost of the components. In tests the gearbox attains an efficiency of well over 98%. Further, by reducing the built-in components its reliability increases. Winergy has manufactured four gearboxes for Adwen with the goal of having them fully validated in three phases. The first one takes place at Winergy on modified test bench which is being used for the back-to-back testing of two identical gearboxes with up to 125% over loading. Adwen’s validation process, the most stringent ever taken on a gearbox and drivetrain this size, requires these tests to guarantee maximum reliability of such a critical component. The second phase takes place at Fraunhofer IWES Test Center’s Dynamic Nacelle Testing Laboratory where the gearbox undergoes exhaustive tests in combination with full drivetrain and nacelle. The final phase is field tests with the installation of the AD 8-180 prototype in Bremerhaven (Germany). “We continue pushing the limits of the industry with our AD 8-180, this time with the largest gearbox ever built. This key component has performed extremely well during the exhaustive validation process which makes us confident the first prototype of the turbine will meet and even exceed our expectations in terms of performance and reliability when it is installed,” explained Luis Alvarez, CEO of Adwen. “In addition, as is the case of all main components, it has been designed with scalability in mind enabling future evolution of the platform.” Winergy CEO Aarnout Kant adds, “Particularly in the offshore sector reliability is the essential thing. With this medium-speed gearbox concept we are demonstrating our technological expertise and innovative strength. The integrated drive system is not only very compact and efficient, it is also extremely reliable. It makes us proud to be Adwen’s partner on this showcase project.”