Part III in our series on the Ocotillo wind turbine collapse
By Miriam Raftery
Photos by Jim Pelley
December 11, 2016 (Ocotillo) – State Senator Ben Hueso (D-40th district) wants to know why a massive wind turbine collapsed on November 21st in Ocotillo on public land—and what will be done to prevent future such disasters.
In a letter to Beth O’Brien, Pattern Energy’s manager of external affairs, Senator Hueso notes that this is the third serious incident that has occurred at the Ocotillo Wind Energy Facilitiy since it opened approximately four years ago. Prior problems include a wind turbine that burst into flames and another that hurled a multi-ton blade onto a public trail.
He indicated that residents have contacted him with concerns and asked him to look into the matter. East County Magazine also contacted the Senator to ask what steps will be taken to protect public safety.
Hueso’s letter states that “the health and safety of my constituents are my utmost priorities” adding that he wants to be sure that activities in or near a residential area do not harm residents.
He asked three pointed questions:
- What is the cause of the failure;
- What is Pattern doing to address this matter; and
- What steps are you taking to prevent this from happening in the future?
Senator Hueso’s office later indicated that he will also be sending a similar letter to the U.S. Bureau of Land Management, since the project is on federal public land.
According to an investigation conducted by manufacturer Siemens, the 500-foot-tall Siemens 2.3-108 wind turbine (number T-126) collapse has been determined to have been caused by a blade failure that resulted in the blade striking the tower, the Ocotillo Wind website reports. The site adds, "The blade failure that occurred in this event was determined to be unrelated to the blade failure observed in 2013 at the facility.”
This failure of T-126 is believed to have resulted from cracks in the structural member of the interior of the blade known as the shear web blade. Siemens claims that it has manufactured over 2,100 turbine blades identical to those at Ocotillo Wind and that this is the first time a failure of this nature has occurred, though the company has had other blade failures elsewhere.
“This type of crack is slow to develop and can be seen via visual inspection of the inside of the blade prior to progressing to failure,” the site states, adding that Siemens has recently begun conducting internal inspections of all blades at Ocotillo Wind. The company statement concludes, “We are committed to complete these inspections and return individual turbines to service only after confirming this type of incident is unlikely to recur.”
Siemens did not comment on whether this "first time" failure of this nature may have been related to Pattern Energy installing larger blades than recoommended for the turbine towers at this project.
For now, three weeks after the collapse, the wind project remains offline.
Residents have also objected to Pattern's statement that the blade fell within a designated setback zone, noting that there are no setbacks to prevent the public from walking near or even directly under the turbine blades--and in fact the earlier blade failure resulted in a multi-ton blade dropped onto a public trail frequented by off-road vehicles in this desert community.Other turbines are close to homes, roads, and Interstate 8.
A website titled Ocotillo Wind Turbine Destruction set up by residents opposed to the project includes a post confirming that the number of technicians has increased tremendously since the collapse. The post concludes, “We still have our fingers crossed on shutting this place down... It has been very very nice without the noise and spinning blades.”