June starts hurricane season, an unsettling time for some people living near our nation’s shorelines. For the next 6 months, communities will be on watch for severe storms and high winds that could potentially knock out power or damage homes and businesses.
Strong winds also put America’s growing fleet of wind turbines to the test. Wind power recently surpassed 82,000 megawatts of total installed capacity, making it the nation’s number one source of renewable generation capacity.
You would think that during hurricane season, more wind means more energy, right? It only works that way up to a point. Wind turbines need to protect themselves just as communities do during tropical storms and hurricanes. To understand what happens, let’s first discuss a wind turbine’s power curve.
The diagram below shows the power output of a turbine against steady wind speeds. The cut-in speed (typically between 6 and 9 mph) is when the blades start rotating and generating power. As wind speeds increase, more electricity is generated until it reaches a limit, known as the rated speed. This is the point that the turbine produces its maximum, or rated power. As the wind speed continues to increase, the power generated by the turbine remains constant until it eventually hits a cut-out speed (varies by turbine) and shuts down to prevent unnecessary strain on the rotor.