Wind Turbines Are Tornado Proof?

June 16th, 2013 by Joshua S Hill

I have a lot of love for the wind turbine and always have. Driving around the southern coast of Victoria, here in Australia, you’ll come across wind turbines spinning majestically within view of the crashing waves that make up our beautiful coastline. The winds are constant, and at times genuinely terrifying, but nowhere near as terrifying as the tornado that ripped through Canadian County in Oklahoma.

A tornado that did little or no damage to two wind turbines located at the Canadian Valley Technology Center (CVTC).

The tornado, as seen in the image above, was massive: it has since been listed as the widest tornado ever measured on Earth, and was home to winds nearing 300 miles per hour. 18 lives were lost as the tornado touched down and tore through El Reno, and no doubt the financial cost is going to skyrocket.

In the wake of the tornado many reports depicted a wind turbine blade detaching from a turbine and demolishing the CVTC child care facility. While the CVTC buildings were severely hit, the two turbines were not the cause of the problem. According to CVTC, the blade that did the damage was a learning tool, bound by steel straps to a block of concrete.

The turbine blade in question
Image Credit: Canadian Valley Technology Center

Bill Hulsey, El Reno Campus Business and Industry Services Director, said the internet stories about the turbine “flying off a tower and into the daycare center” or destroying it are unfortunate and baseless.

The fifteen people who were on campus at the time of the tornado took refuge in the basement of another building, which meant that despite the carnage, CVTC did not suffer any human loss.

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Tags: Canadian County, Canadian Valley Technology Center, CVTC, El Reno Tornado, Oklahoma, tornado, turbine, turbine blade, wind turbine, wind turbine blade

About the Author

Joshua S Hill I'm a Christian, a nerd, a geek, and I believe that we're pretty quickly directing planet-Earth into hell in a handbasket! I also write for Fantasy Book Review (.co.uk), and can be found writing articles for a variety of other sites. Check me out at about.me for more.

Wind Watch

Here’s video of a an EF-3 tornado destroying a wind turbine south of Spivey and west of Duquoin in Harper County, Kansas. https://www.youtube.com/watch?v=Egdtlnv6Gio
- Bob_Wallace
  
  Well, I watched the video and what I saw was one turbine lose its blades when the tornado passed through the wind farm. That’s not what I would call “destroying a wind turbine”.
  
  —
  
  When one googles “Wind Watch” here’s what turns up –
  
  “National Wind Watch is a nonprofit coalition for raising awareness of the shortcomings of industrial wind energy and its negative impacts on the environment,”
  
  Then if you go on to their site what you find is a lot of misinformation about industrial wind. “Industrial wind” is a recent friends of fossil fuels anti-renewable term.
  
  You get BS like this “the giant turbines have not been shown to meaningfully reduce the use of other fuels on the electric grid “.
  
  How stupid would have to be to not realize that if wind is producing electricity then some other generation source isn’t? Most likely dispatchable natural gas turbines.
  
  BTW, people shouldn’t miss Thomas’s article on The Breakthrough Institute and their anti-renewable energy disinformation campaign.
  
  http://cleantechnica.com/2013/06/17/the-breakthrough-institute-why-the-hot-air/#comment-932998769
  
  There’s evil afoot….
- Jonathan_Justice
  
  How helpful of the bit of video to make my points!
  
  EF-3 Tornado snakes through a wind farm hitting just one turbine.
  
  The blades are destroyed. The tower and the generator remain upright.
  
  The rest of the units remain ready to be available to the grid as soon as the wind where they are drops below 49 miles an hour.
  
  Other video I saw showed two turbines entirely surviving a less powerful tornado.
  
  Bob is right to look into the source on this. Wind Watch gives us a bit of slight of information. The imaged event took place last year. By now, the extent of the damages should be clear, even the cost and speed of the repairs. That we are shown an “enhanced” video but not presented with that information raises enough of a question to suggest that Bob is correct in interpreting the video as more likely to be showing blade destruction rather than turbine destruction.
Jonathan_Justice

While it is of interest that the installations hit by this particular tornado did as well as they did, it is important to recognize that EF-5 tornadoes are seriously uncommon. More typical tornadoes are much smaller and hugely less powerful. The relevant question is what balance of safety, efficiency, and cost is going to turn out to be considered appropriate. One might reasonably ask what damage would happen to a typical gas-fired turbine or a 50 year old coal-fired plant in a similar event.

Fortunately, locations where typical wind velocities are high enough to make attractive sites for wind farms are not highly correlated with locations at high risk for serious tornadoes.

One might also note that the path of even a high EF scale tornado probably would not take out a lot of the turbines in a large wind farm, so there would still be some power output to deal with. I’d be more concerned about hardening the transmission system.

I would think that the towers and turbines should be designed to resist a lot more wind than the blades.
- Bob_Wallace
  
  If you look at the size of this record-breaking EF-5 tornado it covered only about 30 square miles. Given that Oklahoma has an area of 69,899 square miles the odds of hitting more than one wind farm per tornado event is pretty small.
  
  The odds of an EF-5 hitting a wind farm are slight.
  
  What’s encouraging to me is this gives us some indication how turbines/blades might stand up to large hurricanes. Hurricanes have much larger footprints.
  - Tongue-In-Cheek
    
    Perhaps the real estate used to locate wind farms would be put to better use housing people, specifically trailer parks!?
    - Bob_Wallace
      
      You might be on to something. We could build trailer parks close to wind farms and residents could shelter inside turbine towers. ;o)
bussdriver78

People forget that the towers are designed for wind and the blades designed to spin quite fast– with the tips of the blades traveling 100s of mph more than a tornado. Not to say it isn’t a problem, but not as bad as people believe.
- Bob_Wallace
  
  I’m seeing max tip speeds under 200 MPH.
  
  http://www.aweo.org/windmodels.html
  
  World’s largest blade –
  
  “Remarkably, the 75-meter-long (246-ft) blades consist of a single component made from epoxy resin and balsa reinforced with glass fiber, cast in a gigantic mold using a process Siemens has cunningly named IntegralBlade.
  
  Initially, three B75 blades will be put to use in a prototype 6-MW offshore turbine at Denmark’s national test center at Østerild. The sweep of the completed turbine will cover 18,600 sq m (200,200 sq ft) and the tips of the blades will move at 290 km/h (180 mph) at full lick. At a wind speed of 10 m/s (19.4 knots), the turbine will be hit by 200 tons (181 metric tonnes) of air every second.”
  
  http://www.gizmag.com/worlds-largest-wind-turbine-blades/23578/
Bob_Wallace

“Last week, the widest tornado ever measured on Earth ripped through Canadian County, Okla., destroying many homes and businesses. This record-setting storm event received an EF5 rating–the highest possible–and was only the eighth tornado of this magnitude to be measured in the state since 1950.

Despite taking a direct hit, two wind turbines at the Canadian Valley Technology Center (CVTC) stood intact after the storm passed. The turbines, on 85- and 126-foot towers–both fully constructed and used for educational purposes–did not suffer any visible damage.”

http://www.evwind.es/2013/06/06/wind-turbines-withstand-tornado-with-nearly-300-mph-winds/33454

Joshua boiled this down to a nutrient-less “A tornado that did little or no damage to two wind turbines located at the Canadian Valley Technology Center (CVTC).”
- Bob_Wallace
  
  More –
  
  In the linked article in the piece it states that the taller tower turbine had blades installed when the tornado hit but the shorter tower turbine did not.
  
  So we have one data point. I would have expected the blades to be ripped off with winds above 200 MPH. I figured that offshore wind farms that are hit by Category 5 hurricanes would need blade replacements. Perhaps not.
Ivor O’Connor

It’s not very clear in this article. How many wind turbines did the tornado touch and what if any damage did they suffer. Some summary stats here, if positive, would be wonderful for the industry.
- Matt
  
  Yes, wheres the beef. Past saying that the blade that hit the CVTC child care facility was ground based demo blade. It really gives no information on the wind turbines in the area.
  - Ivor O’Connor
    
    Probably hard to get the details but if they can be gotten and they are positive the wind industry should publish them everywhere and forevermore!