Hub-Height Wind Speed
Turbines in offshore wind plants must be designed to withstand extreme wind events in the case of mechanical yaw error. This is commonly expressed in terms of the 1-year or 30-year return period for wind speed (Sharples 2009). Such statistical values require multiple years of wind speed time series to compute. There are currently no such long-term observations in U.S. offshore waters except at specific, isolated locations. Two basic options for estimating hub-height wind speed distributions are to use near-surface measurements from widely scattered buoys and other surface platforms and attempt to scale the measurements up to hub height. Currently, such methods lack extensive validation. As an alternative and second option, numerical weather prediction models can provide simulated time series, but these models still need to be validated offshore. With regard to hurricane risk, even long-term records may not be sufficient to assess 50- and 100-year return period winds, necessitating the use of stochastic modeling methods based on the existing Atlantic and Gulf of Mexico basin hurricane climatology.