Wind conditions in category 1-3 tropical cyclones can exceed wind turbine design standards

Offshore wind energy deployment in the US is expected to increase in the years to come, with proposed wind farm sites located in regions with high-risk for tropical cyclones. Yet, the wind turbine design criteria outlined by the International Electrotechnical Commission for extreme events may not account for the severe wind conditions in tropical cyclones, even the weaker storms that are likely to reach mid-Atlantic wind resource areas. To evaluate if current design standards capture the extreme conditions of these storms, we perform idealized large-eddy simulations of five tropical cyclones (two category-1, two category-2, and one category-3 storms) using the Weather Research and Forecasting model. Wind conditions near the eyewall of category-1, category-2 and category-3 storms can exceed current design standards for offshore wind turbines. Hub-height winds can exceed design criteria for Class I and Class T turbines for 50-year recurrence periods. Moreover, wind speed shear across the turbine rotor layer is larger than assumed in design specifications. Vertical variations in wind direction across the turbine rotor layer are also large for tropical cyclones of all intensity levels, suggesting design standards should include veer, which can amplify loads in wind turbines.