Wind turbines have become an extremely common sight throughout the state of Iowa. Fields of corn and soybeans now grow alongside these tall structures, each turning the state’s strongest winds into usable electricity.
Most people now barely even notice them anymore.
One evening, five of those towering turbines were left bent over like drinking straws after a violent storm swept through the area.
Homes had been destroyed, and communities were devastated. Among all the widespread damage caused by the tornadoes, many residents were asking the same question.
How could the wind bend structures that were built to withstand exactly what they were designed for?
The towers weren’t supposed to fall
Iowa is one of the leading states in wind energy production in America.
Thousands of wind turbines have operated throughout the state in strong winds, heavy rain, snow, and harsh seasonal weather.
Modern wind turbines are engineered to operate in demanding conditions. Their steel towers support enormous nacelles and blades.
Sophisticated control systems continuously monitor changing weather to keep the machines operating safely.
Nothing suggested this particular wind farm would become part of one of the most destructive tornado events to strike a U.S. wind facility in decades. When the storms passed, however, five giant turbine towers no longer stood above the surrounding fields.
The destruction extended far beyond the wind farm
On May 21, an unusual event unfolded across parts of Iowa. A violent outbreak of tornadoes caused some of the worst damage in communities like Greenfield.
A number of homes, many businesses, and public buildings were severely damaged or destroyed.
As with all natural disasters, lives were lost.
Emergency responders started rescue operations right away. Community members tried to assess the extent of the damage.
As morning broke over the landscape, another unexpected sight emerged.
Numerous large wind turbines had toppled over. The massive steel towers lay across open fields.
Reports indicated this was the greatest tornado-related damage at a U.S. wind farm in nearly twenty years.
Photos of the damaged turbines quickly spread through news outlets and the renewable energy community.
Many people expected damaged turbine blades after such extreme winds. Few imagined entire towers would look as though they had been bent by hand.
It wasn’t just the wind
At first glance, it appeared as though the wind had simply overpowered the structures. The real answer was far more complex.
These turbines were not defeated by normal wind.
Instead, they were struck by an exceptionally violent tornado.
It exposed them to rapidly changing forces from multiple directions at once. Unlike regular winds, tornadoes twist, rotate, and shift at incredible speeds.
They also push from multiple directions.
Different parts of a turbine can experience powerful forces at the same time instead of from a single direction.
Engineers design wind turbines to withstand extreme weather during normal operation. A direct encounter with a violent tornado is an entirely different type of event.
Instead of enduring steady loading, the towers face rapidly changing stresses that exceed those produced during conventional wind conditions.
That combination of violent rotation and extreme force was enough to collapse five massive steel towers during the storm despite the advanced engineering behind them.
The towers told a larger story
The twisted turbines became one of the iconic images of the disaster.
While they represented a large financial loss, they also showcased the extraordinary power released during the tornado outbreak.
Electricity can be restored. Wind turbines can eventually be replaced.
For many Iowa communities, rebuilding homes and recovering from the human cost of the disaster will remain the greatest challenge.
Those folded towers were never evidence that modern wind turbines were weak. Instead, they demonstrated just how exceptional that tornado really was.
Disclaimer: Our coverage of events affecting companies or institutions is purely informative and descriptive. Under no circumstances does it seek to promote an opinion or create a trend, nor can it be taken as investment advice or a recommendation of any kind.
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