A massive blade broke from a Siemens wind turbine this week – and it’s not the first time this has happened. The latest incident, which took place at Pattern Energy’s Ocotillo wind power plant in Imperial County, Calif., and caused no injuries, has led Siemens to “curtail” the operation of turbines using such blades.

This type of blade is 173 feet long, so when one them comes off, it’s pretty serious business. Longtime opponents of the Ocotillo project, which opened with 94 2.3-megawatt turbines right at the end of 2012, said the incident demonstrated yet another threat among many they believe the turbines pose.

ocotillo turbine blade throw
image via Ocotillo Wind Turbine Destruction

“Since Ocotillo Express operation started in late 2012, residents complain of adverse impacts from noise, vibrations, electrical interference, shadow flicker and light pollution,” the group Protect Our Communities Foundation said in a statement posted on the website of the anti-wind organization Industrial Wind Action Group. “People, pets and wildlife are suffering while the project’s wind production is far less than advertised.”

According to a report yesterday in East County Magazine, the blade was discovered by “ECM photographer and aerospace engineer Jim Pelley.” He “discovered the fallen blade before dawn this morning when he looked out from his front porch eastward and saw the enormous blade … lying on the desert floor,” the magazine said.

image via Ocotillo Wind Turbine Destruction
image via Ocotillo Wind Turbine Destruction

The anti-Ocotillo Facebook page Ocotillo Wind Turbine Destruction wrote that “the blade appeared to come detached, the tip of the blade hit the ground about 100’ to 120’ from the base of the tower and appeared to tumble with the attachment portion of the blade landing about 300’ from the tower.”

In a phone interview with EarthTechling, Pelley said that the turbine incident occurred on land open to and used by the public for dirt biking and other activities, and within perhaps 100 yards of a Bureau of Land Management road.

In a statement, Siemens confirmed the “B53 rotor blade of a SWT-2.3-108 wind turbine broke off near the blade root and fell to the ground at the Ocotillo Wind project in California.”

Siemens said it had “convened a team of experts at the site who will examine all facets of this incident, including the production, installation, commissioning and service of the blade, which is under warranty by Siemens Energy.”

The company went on to say that it was “working to determine if and how this is related to a recent similar incident in Iowa,” and that in the meantime was “curtailing all turbines with the B53 blade type globally.”

In an email to EarthTechling, a Siemens spokeswoman explained that “when a turbine is curtailed, it means the load on the blade is significantly reduced compared to normal operation.” The company said there were about 700 such turbines deployed around the world, with most – around 600 – in the United States, and all those turbines were being examined.

Note: This story was updated to add new information after its initial publication.