China is framing standards for onshore wind projects in typhoon prone regions.
Standardization and quality supervision authorities of China along with a task team led by turbine manufacturer Windey are advising the standards which are to come into effect from February next. However, their implementation is not being made mandatory, Windpower Monthly reports.
The east and southeast coasts of China are typhoon-prone. During the season, wind speeds in the regions approach 144 kilometers per hour.
According to Windey, which has developed high-winds resistant turbines of 1.5 MW, 2 MW and 2.5 MW, it would help manufacturers make quality, typhoon-resistant wind turbines at lower cost.
Wind turbines that need to withstand typhoons require certain special design and control mechanisms such as reinforced blades, triple braking system, and gearless design.
In 2013 Typhoon Usagi devastated Honghaiwan wind farm in Shanwei, eastern Guangdong, about 130 kilometres northeast of Hong Kong.
The onshore wind farm comprised 25 imported Vestas V47 600KW turbines. Of these eight were toppled by the typhoon, and the blades of eight others were severed. The turbines that withstood the winds, too, suffered damage in other ways and the losses amounted to 100 million yuan in losses.
It was the second such incident at the wind farm which was hit in 2003 by a typhoon. Then 13 of the 25 turbines had been damaged and losses were counted at 10 million yuan. Typhoon Maemi also destroyed seven turbines near Okinawa, Japan and Typhoon Dujuan damaged several turbines in China.
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As of 2012 there were 1,200 wind turbines along the coasts of China, northern Europe and Japan.
In their Proceedings of the National Academy of Sciences of the United States of America (PNAS) paper, a research team had recommended developing reasonable safety measures, including increased design requirements and backup power for turbine motors which would allow wind tracking, thereby reducing serious damage by extreme wind conditions.
Another team of researchers from the Stanford University, however, found that offshore wind farms were beneficial in reducing the intensity of hurricanes.
The study said tens of thousands of turbines can lower a hurricane’s wind speed up to 92 mph and reduce its storm surge up to 79 percent.
Ajith Kumar S