GE Grabs Gearless Wind Turbines

[madokie]

http://www.technologyreview.com/energy/23517/?a=f

With a new purchase, GE is betting on an early-stage turbine technology that could make offshore wind farms cheaper to maintain. The acquisition of ScanWind, based in Trondheim, Norway, has also secured GE a foothold in the growing offshore wind energy market.
One speed: ScanWind has been testing gearless 3.5-megawatt wind turbines on the Norwegian coast since 2003.
Credit: GE

Instead of gearboxes, ScanWind uses a novel direct-drive generator technology in its 3.5-megawatt turbines. This makes the turbines more reliable, the company says, by cutting downtime and repair costs--an especially important consideration for turbines offshore, where it's more expensive to send technicians for maintenance. ScanWind has been testing the turbines on the Norwegian coast since 2003.

GE, based in Fairfield, CT, is the world's second-largest maker of wind turbines, with more than 12,000 turbines installed globally. But GE's offshore wind energy portfolio has been minimal so far, and the company wants to expand its offshore offerings. By acquiring ScanWind, transferring its expertise and understanding of onshore wind, and adding technologies such as remote monitoring and sensing, GE hopes it can make a solid, cost-effective offshore wind product.

In conventional wind turbines, the blades spin a shaft that is connected through a gearbox to the generator. The gearbox converts the turning speed of the blades--15 to 20 rotations per minute for a large, one-megawatt turbine--into the faster 1,800 rotations per minute that the generator needs to generate electricity. "Wind turbines are very different than any other gearbox application," says Sandy Butterfield, chief engineer of the wind program at the National Renewable Energy Laboratory in Golden, CO. "You're going from a very low speed to a high speed." Typically it's the opposite.