Wind Farm Management has long discussed the effects of extreme cold on turbine blades. The same can be said for lightning strikes, which can damage electrical systems and cause costly downtime. Advanced fortification materials, lightning protection systems, and continuous monitoring are essential in mitigating these risks and ensuring turbines operate smoothly, even in adverse conditions.
But while these measures are effective against cold and lightning, the unpredictable and violent nature of tornadoes presents an entirely different challenge.
A turbine’s greatest foe?
In May 2024, a powerful tornado tore through a wind farm in Iowa, toppling multiple wind turbines and causing extensive damage. Experts describe such destruction as extremely rare, yet the impact was significant. While some sources have reported that five turbines were flattened as a result, it has been reported by others that up to 10 turbines were destroyed by the tornado, leading to repair costs estimated in the millions.
The worst affected area in the state was the small town of Greenfield, with a population of around 2,000 people.
“Wind turbines are built to withstand high wind speeds and severe weather […] However, few structures are designed to withstand a direct hit from a powerful tornado,” says Sri Sritharan, an engineering professor at Iowa State University who has studied the impact of earthquakes and severe weather on structures.
“When you do a design, you don’t design something that can withstand a level 4 or 5 tornado.”
Sri Sritharan, Iowa State University
Wind turbines are designed to meet industry standards for structural integrity that includes factors like wind speed, and it’s possible that design code committees will consider the impact of recent tornado strikes in the future. Sritharan added, “I would think they would look at this event and how they should update the standards.”
The twister tally
Tornadoes are classified by the Fujita scale, which measures the intensity of tornadoes based on the damage they cause. While an F1 tornado can only really lead to minor structural damage and break a few tree branches, an F5 destroys everything in its path. An average tornado will be in the 100-200 mph range, and a large F5 can go up to 300 mph.
Closer to home
Tornadoes are not confined to North America. Europe has also experienced tornado activity, though these events are typically less frequent and intense. However, with climate change, the unpredictability and potential frequency of such events may increase. This necessitates that European wind farms consider these potential risks in their design and operational strategies to enhance resilience.
Extreme weather poses significant challenges to wind turbine infrastructure. Tornadoes, although rare, can cause devastating damage. The recent incident in Iowa serves as a stark reminder of the potential impact of such natural events. Continuous innovation and rigorous maintenance are crucial in mitigating these risks.
SKF remains committed to supporting the wind energy sector with cutting-edge solutions that aim to enhance turbine resilience and reliability.
