Clipper Windpower Plc has announced that its 2.5MW Liberty C96 Class IIB and C93 Class IIA wind turbines have received Germanischer Lloyd (GL) certification for operation in extreme cold climate conditions.

The achievement marks the first large wind turbine over 2MW to receive the new GL extreme temperature certification. Liberty's standard "low temperature survival" architecture includes metallurgical suitability of components, including main base, rotor hub and gearbox housing. Large, quality, high-strength nuts and bolts are also a Liberty standard, as is special low-viscosity gearbox oil and an immersed gearbox heating system, keeping oil temperatures above 0 degrees Centigrade at start-up. Heavy, cold-weather grease is applied to exposed pitch and yaw bearings. An internal heating system protects sensitive power electronics in the frequency converter and CPU. Liberty is also equipped with a generator heater which is utilized when the generator is cold soaked for a period of time.