A global assessment of extreme wind speeds for wind energy applications

With the increasing growth in wind power installations, turbine deployment locations now include areas for which there is only limited data about wind speeds. Here, Pryor and Barthelmie present a global-scale investigation of extreme wind speeds, comparing different statistical approaches. Cost-effective expansion of the wind energy industry benefits from robust estimates of wind resource and operating conditions. Extreme design loads contribute to wind turbine selection and cost, and are determined in part by the fifty year return period sustained wind speed (U-50). Here we derive a global, homogenized and geospatially explicit digital atlas of U-50 and associated confidence intervals based on ERA5 reanalysis output at wind turbine hub heights. U-50 estimates derived using ERA5 output and four different methods are shown to lie within an average of 9-13% of those from point measurements. The reference wind speed (U-ref) derived using five times the mean wind speed as specified in the wind turbine design standards is generally a conservative estimate of U-50. Particularly after application of additional safety factors, this may result in over-engineering of wind turbines and excess capital expenditures.

Automated summary

This study presents a global investigation of extreme wind speeds using different statistical approaches, providing robust estimates of wind resource for cost-effective expansion of the wind energy industry. The study shows that estimates of U-50 derived from ERA5 output using four different methods are within an average of 9-13% of those from point measurements. The reference wind speed (U-ref) derived from wind turbine design standards is generally a conservative estimate of U-50 and may lead to over-engineering of wind turbines and excess capital expenditures, especially after applying additional safety factors.