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Costs and Dangers of Wind Turbine Failures

October 13, 2015

Wind turbine failures are likely to become more important as older turbines, built before 2010, come out of warranty.

There are many unknowns about how wind turbines will weather aging, as none of the modern designs have been in operation for their full twenty years of expected life.

Undoubtedly many components have been subjected to twenty year accelerated life tests, but these can only identify the most obvious of weaknesses.

Two components seem to be most vulnerable:

  • Blades
  • Gear boxes

Three systems appear to have the highest failure rates:

  • Electrical system
  • Gear boxes
  • Generators

The cost of repairs are affected by whether cranes are required when making the repair, which frequently means that gear boxes, generators and blades have high repair costs.

Blades are numerous and failures can be dangerous.

One estimate is that 1% to 3% of turbines require blade replacement annually.

There were 33,250 turbines installed between 2007 and 2015, indicating that between 300 and 1,000 blades need to be replaced each year.

The cost of each blade is around $150,000, according to an NREL analysis. If 1,000 blades are replaced each year, the cost will be around $150 million, not including the cost of installing the new blade.

Crack repair in progress. 2013

Blade repair in progress, 2013

Blade replacement costs are not a trivial matter, and have largely been covered by the manufacturer while units were under warranty. Now, the cost will increasingly shift to the owners of wind farms.

Blade failures are no trivial matter. Blades weigh around 24,000 pounds, or 12 tons.

Catastrophic blade failures have thrown portions of blades, or entire blades, onto surrounding areas, which for the most part have been rural farmland.

But communities should be careful not to have wind turbines installed near buildings, such as schools and hospitals, as a broken blade, that weighs 4 times more than a Tesla S sedan, could cause considerable damage. Potentially, these are life threatening installations.

According to an NREL report, gear boxes represent 6% of all failures, but account for the largest amount of downtime.

Gear boxes cost around $250,000. The cost of replacing a gear box is substantial when the cost of crane rental and the cost of lost production, from long down times, are taken into consideration.

As units go off warranty, owner-operators must decide whether to enter into extended warranty agreements with the manufacturer, or into warranty and maintenance agreements with third party service companies … or manage the maintenance costs themselves.

In each case, the owner-operator must contend with equipment that’s supposed to operate for twenty years, but where none of the existing equipment has ever done so.

This creates a huge unknown for the future cost of wind generated electricity.

The original equipment manufacturer (OEM) has extensive data on maintenance costs and failure rates across all of its installed base. OEMs guard this proprietary information carefully, as it provides them with the advantage of being in the best position to predict future maintenance and failure costs.

The government and some industry members are upset over this practice, claiming that the industry would benefit if all such information was made available to everyone.

Third party service companies may have data on equipment manufactured by several OEMs based on maintenance contracts they have performed, but have less information than OEMs on OEM equipment.

The owner-operator of a wind farm is at a disadvantage when deciding how to handle its maintenance and service costs after the warranty has expired. Any equipment that fails out of warranty will be replaced at a very high price if it isn’t covered by a service agreement.

The owner operator’s best alternative may be to enter into an agreement where the OEM or service company guarantees yield or output, under specific operating conditions.

Since most modern wind turbines in the United States haven’t operated for more than seven years, there is great uncertainty whether maintenance and failure costs will increase significantly over their remaining lives.

The real cost of maintenance is being absorbed by OEMs during the warranty period, and will continue to be absorbed by them when they provide maintenance contracts. As a result, the true cost of maintaining wind turbines is largely hidden from view.

If the cost of maintenance contracts increase, the already high cost of electricity from wind is also likely to increase.

Eventually, the cost of decommissioning existing units will also have to be accounted for, and it’s not clear who will absorb those costs … wind farm owners, or the land owners on which the turbines are built.

The next decade could provide a better understanding of the levelized cost of electricity form wind turbines.

* * * * * *


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8 Comments leave one →
  1. October 13, 2015 10:46 am

    Thanks for another good article Donn.

    I can tell you that we are constantly witness to just how often these giant lemons break down here in western New York State. Invenergy’s relatively-new, 58-turbine project here in Orangeville, NY, had to be shut down before it ever even went online after one of the turbines threw a blade during testing. Fortunately, the fragments of this 11-TON BOMB didn’t hit anyone. Most of Invenergy’s turbines in Orangeville are sited dangerously close to high-traffic roadways and peoples’ homes. It’s just a matter of time before a tragedy occurs.

    Recent Corporate trends are very clear – when it is convenient for corporations to shed their responsibilities and legally-binding pacts, they do so with increasing regularity. When pressed for an answer by an astute Town Board member at a “Local Government Workshop” held here in western New York State years ago, one of Invenergy’s attorneys finally admitted that if the wind companies abandon the project – whatever the reason, “THE LANDOWNER WILL BE LIABLE.”

    This 2009 article discusses the fact that Lackawanna’s Steel Winds project had to be disassembled and replaced twice in the first two years of operation:

    Despite what industry salesmen say, wind is not the future:

    In case you haven’t seen it, here is an excellent site that is tracking the wind turbine accidents/failures world-wide:

    Summary of Wind Turbine Accident data to 30 September 2015:

    • October 13, 2015 11:30 am

      Thanks for your excellent comments. I had not seen the list of wind turbine accidents, and appreciate your providing the link.

  2. permalink
    October 13, 2015 11:10 am

    I blade that you show being repaired fail again and needed to be replace per my friend in WNY

    • October 13, 2015 11:26 am

      Thanks. Very interesting. Hope you are doing well.

  3. Neil Jones permalink
    October 13, 2015 5:00 pm


    Good piece. Most folks I talk with about the “Green” issue have not given safety, maintenance, or replacement costs of the wind machines any serious thought. It’s easy for us all to presume that since the wind is free, except for the occasional squirt of oil, once erected the machine runs more or less forever. Thanks for the “heads up.”


    • October 13, 2015 5:08 pm

      Thans for your comment. I agree, most people don’t think much about what happens while they are in operation or what happens when the fail or will be decommissioned.


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