COLUMBUS – A wind turbine blade failure incident on April 24 in Paulding County threw a piece of debris weighing approximately 6.6 pounds as far as 764 feet from the turbine’s tower base, according to a report filed with the state of Ohio on Friday.
Timber Road II Wind Farm near Payne had to be shut down in April after two blades shattered and sent debris raining down on farm fields below. No one was injured.
According to EDP Renewables and the turbine’s manufacturer, Vestas, the first of two blades broke due to a carbon fiber defect and the second blade broke as a result of a load problem resulting from the first blade’s failure. According to the report, Vestas restarted the turbine via a remote system, causing the turbine further damage after the first blade failed. It was determined the first blade had “a wrinkle in the carbon fiber” of its supporting structure. This caused it to fail under “high loads for a low number of cycles.” The failure reportedly was categorized incorrectly in the computer system, resulting in the turbine being restarted remotely.
The report states that Vestas now requires technicians to sign a document stating this particular alarm category will not result in a remote restart and that a turbine involved in such a failure will be inspected before being restarted. Also, Vestas says software is being changed to block remote starts following this type of alarm.
The wind farm’s 55 turbines are now going to be incrementally restarted under a “load reduced mode” – presumed to be safer – in order to control for any potential defects that could be present in other blades. Vestas proposes a staggered start-up as the facility resumes operation, a 30 percent reduction of turbine loads until normal operation is approved and routine blade inspections.
Vestas continues investigating and is attempting to sort which blades are at-risk and which are not. The companies also plan to implement new visual procedures to inspect blades at the farm for damage. A second, unrelated turbine in Timber Road II was also found during the investigation to be damaged, according to the report. Of the 55 turbines built, 53 are set to be phased back into operation under the reduced mode. The wind farm could be placed back into regular operation without reduced load once it is deemed safe.
The Ohio Power Siting Board answered findings by Vestas and EDP filed Friday by approving plans for restarting the turbines at Timber Road II. Vestas stated in its report this is the first failure of its kind on this specific turbine model in North America.
What it means locally
Opponents and proponents of two proposed wind farms for Champaign County have been following the Timber Road II investigation closely. Setbacks from EverPower’s proposed turbines in Champaign County include turbine bases to be sited as close as 541 feet from non-participating property lines and as close as 914 feet from inhabited residences. The six-pound piece of debris thrown in Paulding County would have fallen within the allowed setback for adjacent property lines, but not as far as an inhabited structure setback. Debris smaller than six pounds was not specifically noted in the report filed with the state.
Opponents of the Champaign County proposed projects have long insisted the state setback formula does not adequately protect nearby properties, residences, structures and their inhabitants. The wind farm’s applicants, Buckeye Wind and Champaign Wind formed by EverPower, contend the state’s setback formula is sufficient. Buckeye Wind was approved for construction with the power siting board’s decision upheld by the Ohio Supreme Court in March. Subsequently, EverPower filed its application with the state in May to build Champaign Wind.
EverPower has not ruled out using Vestas turbines in its project, according to company spokesmen contacted by the Daily Citizen within the past six weeks. It is considering several turbine manufacturers and has not yet confirmed which ultimately will be used.
If both farms are constructed as approved and proposed, the eastern side of Champaign County would host up to 110 utility-scale wind turbines as high as 492 feet from base to blade tip. The projects would also build infrastructure poles and lines to carry electricity to the grid. Construction could begin in 2013.
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