Siemens Energy officials ordered wind turbines using its B53 rotor blade – manufactured at its Fort Madison, Iowa, plant – to run at significantly reduced speeds while the company works to determine what caused two blades to fall from turbines at two wind farms in recent weeks.
It’s unclear what – if anything – the incidents could mean for Siemens nacelle manufacturing plant in Hutchinson. The blades are paired with the type of nacelles manufactured here.
The latest incident was on a turbine at Pattern Energy’s recently completed 94-turbine Ocotillo Wind Project in California, about 75 miles east of San Diego, which came online in December. The 10-ton blade on a Kansas-made SWT-2.3-108 wind turbine broke off May 16 near the blade root, where the blade attaches to the nacelle, and fell some 240 feet to the ground in the middle of the night.
A blade on the same model of turbine broke off at MidAmerican Energy’s 200MW Eclipse wind farm in Iowa on April 5. There were no injuries from either incident.
After the second incident, Siemens ordered all turbines globally that use the blade “curtailed,” which means reducing the rotor speeds and output power of the turbines, said Monika Wood, corporate communications director for Siemens’ Wind Power Americas.
“The turbines will remain curtailed until it can be determined they are not at risk of a similar malfunction,” according to a statement from Wood. “As the inspections and analysis progress, Siemens will make further determinations on curtailment protocols.”
There are currently about 2,100 B53 blades in use on about 700 turbines worldwide, with 600 of those installed in the U.S., Wood stated.
Siemens Energy sent a team of experts to the site to “examine all facets of this incident, including the production, installation, commissioning and service of the blade, which is under warranty by Siemens Energy,” the statement said regarding the California incident. “Siemens does not yet know the root cause of this incident and is working to determine if and how this is related to a recent similar incident in Iowa.”
According to Siemens’ website, the company makes the 108-meter blades, which it introduced in 2011, from a series of spars and shells cast in a fiberglass-reinforced epoxy resin in a single process. The process eliminates glued joints, giving the blade “both low weight and enormous strength.”
Asked about pending orders at the Hutchinson plant for nacelles that will use the B53, Wood stated in an email “Siemens does not provide information on production schedules or on how many blades for SWT-2.3-108 wind turbines are on order at this time.”
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