Wind turbine rotor blades are failing at a rate of around 3,800 a year, 0.54% of the 700,000 or so blades that are in operation worldwide.
The figures, from research carried out by renewable energy undewriter GCube, were delivered by Andrew Bellamy, former head of Areva’s 8MW blade programme, in his opening address to Windpower Monthly’s blade manufacturing and composites conference in London on 12 May.
Bellamy, co-founder of renewables advisory firm Aarufield, pointed out that blade failures are the primary cause of insurance claims in the US onshore market. They account for over 40% of claims, ahead of gearboxes (35%) and generators (10%).
The wind industry also faces a struggle to secure the carbon fibre materials it needs for lighter and stronger blade designs, warned Bellamy.
“There’s growing competition for these materials from the automotive and aerospace industries,” he said. “And they are willing, and able, to pay more than we are.”
Recent examples of blade failures include a blade from a Vestas V90 3MW turbine that snapped on a wind farm in the north of Denmark last year. At the time, Vestas said the winds were not particularly high.
In another case last year, GE was forced to replace 33 blade on its turbines at a Michigan wind farm after a blade broke on the project.
GE put the failure down to a “spar cap anomaly”. It was the second such incident involving the 1.6-100 model, and was followed by a third at the 94MW Orangeville wind farm in New York State, also in November.
Possibly the biggest blade issue was faced by Siemens in 2013 when it was forced to curtail around 700 turbines worldwide. This was caused by a bonding failure in its B53 blade.
[See also: “Does The Wind Industry Have A Blade Problem?” – North American Windpower, May 2015: “DNV GL has compiled blade failure rates from 10 GW of operating wind projects and found that 1% to 3% of turbines in North America require blade replacements annually in the first 10 years of operation, with the highest failure rates usually occurring in year 1 and year 5.”]
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