Washer suspected to have caused turbine collapse
It was suspected that a washer was forgotten inside the hub of a wind turbine under repair that subsequently collapsed hours later, labour department documents show.
E-mails between the investigating body, the Department of Labour and Advanced Education, and turbine manufacturer Enercon were recently disclosed by the department.
In the Point Tupper incident, workers were told to leave the tower before it buckled and fell. Enercon crews at the time were in the process of replacing a component as part of regular maintenance at the wind farm at the time. They were evacuated and no one was injured.
In January, the Cape Breton Post made a request under Freedom of Information for the labour department’s report on the investigation into the collapse, after another unrelated collapse occurred at a turbine in Grand Etang, Inverness Co.
The Point Tupper wind farm has an 80-metre Enercon turbine model manufactured in 2010.
In one of the emails, a managing director with Enercon whose name is redacted states that on Aug. 16 a damaged hub was removed and placed on the ground at the foot of the turbine. The blades were removed and installed on a new hub. It states that “technical challenges were encountered but were overcome upon consulting technical support.” The hub was then lifted and attached and the blades were pitched out of wind.
The next day the turbine was being assessed and the blades were left pitched into the wind. When the rotor was unlocked, a noise, suspected to be a forgotten washer in the hub, was heard. An Enercon technician opened the hatch to look for it, noting that the blades were pitched in and without having a brake applied, and told workers to climb down and go to another work site.
“Emergency response followed Enercon procedures as tower was evacuated as soon as situation became dangerous,” the email reads. “The site was cleared soon after workers evacuated the tower and every personnel remained out of the danger zone, which is defined as the area around the tower that is equal to half the rotor diameter.”
Four hours after the evacuation, the tower collapsed.
Initially, when The Post requested the Department of Labour and Advanced Education’s report on its investigation into the collapse, it was told the investigative file contained more than 1,200 pages of documents that would require 60 hours to process and would cost a total of $1,890 to obtain.
A modified request for the final report of the investigation was ultimately processed.
The file also shows that a stop-work order related to the demolition and removal of the collapsed turbine was issued to Enercon on Oct. 21. It indicated the company contravened the Occupational Health and Safety Act, saying it needed to obtain a written report of an assessment by an independent professional engineer with working knowledge of wind loading, structural towers and supports and turbine mechanical operation. The company was given a deadline of Nov. 21 to comply with the order.
It was also ordered to take other steps including providing names and contact information for all employees involved in the hub exchange, their jobs titles and tasks, their statements, a chronological written description of what was done to the turbine and its components after receiving the error code message for the bearing failure in March 2016 leading up to the collapse.
The last remaining piece of documentation was received by the department on Dec. 16 and the stop-work order was lifted.
In January, an official with Enercon told The Post its investigation found nothing to indicate it was due to an equipment design or a technical issue but wouldn’t say what the factors behind the failure were.
The Point Tupper wind farm has an 80-metre ENERCON turbine model manufactured in 2010.
The company’s business development manager told The Post it was “confident that we have identified the contributing factors and the continuous improvement opportunities and at this point in time we are in the process of implementing them.”
Despite being asked several times to specify what the “combination of factors” leading to the collapse were, she declined to elaborate.
Enercon said in a statement at the time of the Point Tupper collapse that it has installed almost 1,000 wind turbines in seven provinces in the past 15 years, and it was the first time one of them had collapsed. The 10 other E-82 turbines at the Point Tupper site were not affected.
At the time of the Point Tupper collapse, the Canadian Wind Energy Association, which represents the industry, issued a statement saying it was not aware of a similar failure among the more than 6,000 wind turbines in Canada.
Coincidentally, in January another turbine in Cape Breton failed. In that incident in Grand Etang, the main tower snapped in two after being pounded by strong southeast winds, known as les suêtes, that hammer the Cheticamp area with gusts of up to 200 km/h. That turbine was manufactured by another company than those at the Point Tupper wind farm and that turbine had been in service since 2002.
NSPI is a minority partner in the Point Tupper wind farm with majority owner Renewable Energy Services Ltd.
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