Quantifying the hurricane risk to offshore wind power in the U.S.

Developers in the United States are planning offshore and coastal onshore wind farms in areas of the Atlantic Ocean and Gulf of Mexico that are prone to hurricanes. Those hurricanes pose a risk to current turbine designs-a typhoon that struck Okinawa, Japan destroyed or extensively damaged six wind turbines designed to current standards.We present two methods to estimate the hurricane risk to offshore wind turbines. One estimates the risk to a wind farm using compound probability distributions fit to historical hurricane data. The other estimates the riskusing Monte Carlo simulations with simulated hurricanes. We apply both methods to a generic 5-MW offshore turbine design in two loading cases-head-on wind (parallel to nacelle axis) and broadside wind (perpendicular to nacelle axis).We find the risks to offshore wind turbines in the Gulf of Mexico are high enough to warrant higher design reference wind speeds than are currently used for turbines in northern Europe. The risks are much lower for a turbine pointed head-on into the wind than for a turbine broadside to the wind, which suggests that turbines designed to current standards can operate with low risk in hurricane-prone areas if they can track the wind direction even when grid power is lost.