GL Renewables Certification (GL RC) is bringing attention to the need for wind farms to withstand severe storms.
As wind energy production expands around the world, GL RC says, an increasing number of onshore and offshore wind farms are proposed for tropical, cyclone-affected areas, mainly in the U.S., China, Korea and Japan.
Recent tropical storms – such as Hurricane Irene, which left a trail of destruction along the Eastern Seaboard of the U.S., and Typhoons Megi and Songda – have demonstrated the potential of extreme weather to impact offshore wind farm sites.
The lack of clear guidance for categorizing the risk a site faces of being hit by a tropical storm – and the extreme variability with which such storms affect wind farm structures – means that developers are left with the uncertainties as to how to deal with extreme weather conditions.
"There are a number of key factors to consider in assessing whether a particular turbine design or wind farm site can cope with the stresses of tropical cyclone conditions," explains Mike Woebbeking, vice president of GL RC. "For example, the category of the hurricane faced, assessment of the site and climatic forecasts, predicting wind speeds at their extremes, the ultimate load on the turbine and turbulent wind conditions in these storms."
Wind turbine design for tropical cyclones is one of several issues the company is focusing on in its research and development activities. The expansion of wind energy generation into storm-prone areas and the increase in the frequency of extreme weather events means that both developers and designers are relying on the development of guidelines for the construction of storm-safe turbines, GL RC explains.
The company will develop a technical note for wind turbines in tropical cyclones, which will be a supplement to GL RC's Guidelines for the Certification of Wind Turbines. The technical note will be prepared in cooperation with academia and the industry, and will include knowledge from research and experience from already existing wind farms.