Offshore windmills pose no environmental or socioeconomic risk, according to the Interior Department. But the department didn’t consider this:
In certain risky offshore regions off the Atlantic and Gulf Coasts, there is a high probability that at least one turbine would be destroyed by hurricanes within 20 years, and a smaller chance that half the turbines in a farm would be wiped out.
Current windmills are designed to withstand gales in the North Sea, which, while rough, are nothing next to a Cat 3 hurricane. So windmills could snap off.
It would help if windmills could spin to face the wind, called yawing. Many windmills yaw, but need electricity to do it. But in a big storm, power out to the windmill would be cut off.
The study calls for stronger windmills and battery backups to the yawing mechanism.