Bill Montgomery, UH Energy Fellow

Wind turbinesspin in antarctica, in Quebec and Norway, even during harsh winters. The story is the same in Iowa, North Dakota and even Arctic Russia.

But ice built up on a number of wind turbines during the February freeze-up in Texas, forcing them to shut down to avoid damage or destruction from load imbalances and vibration and to prevent them. to throw pieces of ice across the landscape.

The judgments raise questions about the state’s more than 13,000 turbines. Is winterizing the best solution for them? What does wintering mean exactly? How does the economy work to handle the hard-to-predict cold weather explosions in Texas?

Hadi Ghasemi, professor of mechanical engineering at the University of Houston and chief technology officer for the Houston-based company Elementary coatings, said the way to prepare wind turbines for extreme cold is as follows:

“Basically, it’s insurance on your assets. So you pay a small amount for these technologies – it’s not that much – but you make sure that when you need them, they are fully functional. ”

Turbine blades can be prepared for severe cold through active systems, which heat the blades, or via a passive approach, such as coatings. Wind farm operators can purchase cold weather kits that protect components such as the gearbox and motors, as well as through heaters in the nacelle of a wind turbine. the Canadian government said with these measurements, turbines can operate at temperatures down to minus 22 degrees Fahrenheit.

With no financial incentive for operators to winterize turbines or penalties for not doing so, Texas turbines have been left at the mercy of the elements. A lot stopped.

Hui Hu, professor of aerospace engineering at Iowa State University, who has done extensive research on wind turbine icing problems, told UH Energy that Texas’ choices for winterizing turbines were unclear. He said he couldn’t remember a time in the past two decades when Texas wind generation took such a hit.

Thinking about winterizing wind turbines, he compared the situation to buying a car. If you only used heated seats once in the life of the car, would you spend the money to buy them?

Hu added that the Texas wind turbines faced a big problem during the recent freezing weather, due to the moisture accumulated on the turbine blades and ice. Humidity is the key. Most Iowa turbines normally don’t have a big problem with ice buildup due to lower winter humidity.

When ice forms on turbines, it can reduce electricity production by up to 50% of normal, he said.

Hu said the price per turbine to deal with winter conditions is 5% to 10% more than that without, or up to $ 400,000 more on a utility-scale 2.5 megawatt wind turbine, according to the chosen system.

Lasse Hietikko, Head of Business Development at Wicetec, a Helsinki, Finland-based company that installs carbon-fiber-based heaters on the surfaces of wind turbine blades that operate automatically, told UH Energy that it probably wouldn’t be wise to install systems anti-icing on all Texas turbines.

“The older and smaller should be left out because it probably wouldn’t make sense,†Hietikko said. “However, with the energy price of $ 9,000 per megawatt hour occurring in Texas, the payback time would only be a few days on the larger turbines. If severe icing occurs, say, three times over the life of a turbine, there could be a business case.

“But if we look at the issue from an energy supply point of view, it becomes more and more critical to prevent all wind energy from disappearing from the grid at the same time.”

In other words, if much of the wind power is taken off the grid within minutes, thermal power plants do not have enough time to step in and fill the void, so the case may be stronger for anti-icing systems on many turbines.

On the Wicetec system, the energy consumption of the anti-icing blade heating system is about 0.2% of the long-term turbine output on a wind farm where icing occurs regularly, Hietikko said. .

Wind energy players such as Siemens, Gamesa, Enercon, Nordex and Vestas are also developing technologies for against the winter weather.

Elemental Coatings of Houston works on the passive side of turbine wintering. It manufactures materials that prevent the build-up of ice and scale, which form from minerals in water, on a range of surfaces. The company, which was established in 2018, is based on technology developed by Ghasemi and licensed by the University of Houston. The company has not yet used its products on wind turbines but has tested its products in this area.

Elemental Coatings CEO Brian Huskinson said he expected to be ready to coat the wind turbines in the winter of 2022.

He said it was telling that companies haven’t invested in winterizing their wind turbines in Texas. “There is no doubt that the calculation is uncertain, because if it were clear, then it would be done from a purely economic point of view. Otherwise, we would have to believe that many dozen independent operators are making incorrect and unprofitable decisions, which I find hard to believe, â€said Huskinson.

But that was before last month’s epic blackout, with overall costs measured in lives and billions of dollars in damage. Total damage estimates reached $ 90 billion or more.

“If you include those kinds of effects, the calculations would overwhelmingly be favorable to wintering,” Huskinson said.

“In Texas, I think we’re in a nice situation where a lot of active heating probably doesn’t make a lot of economic sense. We have a cheaper solution that still provides a good solution around the ice, â€he said.

Huskinson admitted that keeping the wind turbines running during the crisis would not have been enough. But it would have helped.

“If the wind had stayed where it was before the fall, it still wouldn’t have prevented the blackout situation because we were short by several tens of gigawatts on the supply side,†Huskinson said.

“Our experience in talking to owners and operators is that they know the economics of their turbines,†said Allen Hall, CEO ofWeather Guard Lightning Tech in Williamstown, Mass.

And knowing the economy will be crucial as Texas lawmakers and regulators decide how to proceed to increase network resiliency. Deciding who will pay and which sources of energy will bring in the most money will be big decisions. Keeping the turbines rotating even in a very cold winter storm would contribute to the resilience of the network.

Bill montgomery is a Houston-based writer and editor. He worked for the Houston Chronicle for over three decades, mostly editing energy-related stories. He holds an MA and BA from the University of Illinois.

UH Energy is the University of Houston’s hub for energy education, research and technology incubation, working to shape the energy future and forge new business approaches in the energy industry. energy.