The average power rating of a utility-scale wind generator is expected to reach 2.4 MW by 2017, according to a report from IMS Research.
The report, ‘The World Market for Wind Generators,’ concludes that wind turbines and wind generators will continue to grow larger in average physical size and in average output.
In 2011, the average power rating of a utility-scale wind generator was 1.75 MW, IMS notes.
With many wind farm projects consisting of more than 100 wind turbines, the relatively minor increases in average output power per turbine can add up rapidly, concludes IMS.
‘Based on the physics principles involved, a relatively small increase in a wind turbine's blade length and the corresponding swept area exponentially expands the amount of wind energy that is captured and then converted to electricity by the generator," says Greg Johnson, generators analyst at IMS. ‘Therefore, the utility-scale wind generators market continues to move toward generators with higher output power ratings to keep pace with the growing size of wind turbines.’
In order to operate at medium and slow speeds, a wind generator's physical size greatly increases in order to incorporate the large number of magnetic poles required.
For example, a standard high-speed wind generator consists of 4 magnetic poles, while a slow-speed, direct-drive generator can have upward of 50 magnetic poles and a diameter of more than 7 meters. Based on these factors, wind generator suppliers must keep pace with the market demand for bigger wind generators and adjust their manufacturing procedures and facilities accordingly.