wind going gearless:
Gearboxes are basically problematic because they have numerous moving parts that wear out over time. It has gears that ramp up the speed of a shaft connected to the turbine’s blades from 10 to 60 rotations per minute to about 1,200 to 1,800 rpm, the speed needed by most generators to create electricity.
In 2007, the United States National Renewable Energy Laboratory pointed out in a study that majority of gearbox failures originate from defective bearings that suffer tremendous stress because of wind turbulence. A small defect in any one component can bring the turbine to a halt. This makes the gearbox the most expensive component to maintain...
...On average, gearboxes need 12 moving parts, 24 bearings and two hydraulic systems to function. A direct-drive system needs only the shaft, its only moving component, and two bearings to work... offshorewind.biz
(March 2010) General Electric announced an investment of 340 million euros in manufacturing facilities to build its own four-megawatt direct-drive turbines for offshore wind farms...Siemens erected a prototype of its machine in Brande, Denmark, in December and plans to install 10 more this year (2010), primarily in Denmark, before beginning mass production in 2011. GE's technology, which it acquired with the purchase of Norwegian turbine producer ScanWind last year, is being demonstrated at a test site in Norway; commercialization of its four-megawatt machine is slated for 2012. technologyreview.com
Siemens Launches Permanent Magnet-Based Gearless Wind Turbine:
Progress in the development of commercially-viable direct drive wind turbines took a significant step forward last week, with the official launch by Siemens Energy of its SWT-3.0-101 wind turbine. This turbine has a faceplate rating of 3 MW, has no gearbox and uses a permanent magnet generator to produce electricity. What’s really interesting about this system is that according to Henrik Stiesdal, Chief Technology Officer for the Siemens WInd Power business unit, the turbine produces 25% more power than the Siemens 2.3 MW machine – but does so with less weight and only 50% of the parts. The nacelle which contains the machinery at the top of the tower, weighs just 73 tonnes. Because of its compact size, the nacelle can be transported using fairly standard vehicles. seekingalpha.com
With improved equipment efficiency, improved turbine siting and higher hub height, the overall production efficiency has increased by 2-3 per cent annually over the last 15 years. renewableenergyworld.com
my comment: GE and SI look like the leaders in gearless wind designs. This will give them an advantage in offshore wind. |
