The footage from southwest Iowa was shocking: In the wake of the tornado, wind turbines were snapped in half like cheap straws, hubs engulfed in flames and thick black smoke, blades lying on the ground.
“You can see several large wind turbine towers that were destroyed,” Zane Suttle, a meteorologist with KCCI 8 News in Des Moines, told viewers. “This is a big tall one. I think it's about 250 feet tall. Well, that tornado took them out.”
But wind turbines are rarely destroyed by tornadoes or other severe weather, said Fraser McLachlan, chief executive of GCube, a company that insures renewable energy projects such as wind farms and solar panels. says.
Thanks to advances in technology since their initial designs in the 1990s, turbines are now built to withstand disasters such as tornadoes, hurricanes, and typhoons. It has a built-in mechanism that locks and feathers the blades and changes their angle when the wind reaches 55 mph. This reduces the surface area of ​​the blade facing the wind.
“You're going to lose a blade here and a blade there during a storm,” McLachlan said, but it's rare for one to be knocked out completely.
The damage to three turbines in Iowa was part of severe weather that hit the state on Tuesday, killing multiple people and injuring at least a dozen others. The storm followed other deadly weather events in the region, including in Missouri, Illinois and Kentucky. This is part of a trend scientists say. As average temperatures rise, severe storms are becoming more frequent and more powerful, but it's not always clear why.
As wind and solar power generation expands, disasters are becoming more common in the Midwest.
Roughly two-thirds of Iowa's net electricity generation in 2022 came from renewable sources, nearly all of it from wind, according to the U.S. Energy Information Administration. The state was second only to Texas in wind power generation. Wind power accounts for 62% of Iowa's net electricity generation, the highest share of any state.
When it comes to extreme weather and renewable energy, McLachlan said the bigger issue is solar panels' vulnerability to hailstorms.
To cut costs, the panels have gotten larger over time and the glass has gotten thinner, making them more susceptible to shattering when hit by hail, as more solar panels are installed in the hail-prone Midwest and hail events become more frequent and severe.
McLachlan says the standard way to protect solar panels from hail is to angle them so that their surface is not exposed to direct impact, but that creates a new problem: These panels start to act like sails, making them more vulnerable to being blown away by hail-related winds.
A GCube report last year found that hail accounted for 54% of solar sector insurance claims costs over the past five years, but only 1.4% of claims amounts. McLachlan said the rising risk of hail losses was making it harder to insure solar projects.
Still, renewables aren't the only power generation industry facing threats from extreme weather, said Elise Caplan, vice president of regulatory affairs at the American Renewable Energy Council. Periods of extreme cold could shut down natural gas facilities, she said, and drought could limit nuclear power plants, which need cooling water.
“There's no perfect generating resource,” Caplan says. “There are different kinds of extreme scenarios that will impact a generation in different ways.”
Kaplan said the focus should be on a mix of generation types and expanding transmission lines to get power to where it's needed most.