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BOSTON — Tucked in the corner of a vehicle shipping port along the Mystic River sits an unassuming gray building bearing a weathered state seal. Built in 2011, the Massachusetts Clean Energy Center wind technology facility has tested more than 50 models of land-based and offshore wind turbine blades over the last decade.
Blades arrive by road and river, with cranes and trailers carrying them through the center’s large garage door. Scientists visually inspect the unfinished components and then affix hundreds of sensors — called strain gauges — that converge into dozens of cables. They feed information from the blade into a windowed control room above.
Staff with hydraulic wrenches screw the blades into the center’s concrete wall. (The concrete was poured continuously for 36 hours, separately from the main floor, so that the whole building doesn’t shake.) The engineers then subject the blades — up to three at a time — to all sorts of stress and fatigue tests.
They’re shaken up and down, extended and flexed, shifted side to side, and sometimes pushed (purposefully) to failure. In six to eight months, the center’s machinery simulates the wear and tear of 20 to 30 years, the planned lifetime of a turbine.
The facility is one of a handful of turbine-blade testers in the world, and was the first in the U.S. capable of testing larger blades. The center evaluates new blade models before they can be approved for commercial manufacture and used in projects. Blades from Europe, Asia and North America, from all the major turbine manufacturers — Siemens Gamesa, Vestas and GE — have come through.
That includes one of the largest turbines on the market today, the Haliade-X, the model used for the Vineyard Wind project.
Because MassCEC tests blade design prototypes, its testing does not prevent flaws or problems that may emerge later, including during the manufacturing process. For instance, MassCEC did not test the exact blade that failed at Vineyard Wind in July. Rather, it tested a design prototype of the Haliade-X blade.
(GE Vernova, the blade’s manufacturer, has stated the failure was due to a manufacturing defect in which insufficient adhesive was applied in the building of the blade. The manufacturing defect has resulted in layoffs and suspensions at the blade plant in Gaspé, Quebec, where a local radio station reported that managers at the LM Wind plant may have falsified quality testing data.)
Plans call for the MassCEC center to grow in order to test even longer blades. The Light took a look inside.
Edge fatigue, flap fatigue
Hard hats and protective glasses are required wear on the main floor where the testing happens. Along one side are small rooms for tools, hydraulic pumps, and repair work.
In early October, three blades were at the testing center, but only two were connected to the wall. Sensors and cables adhered to the blades, and while the blades weren’t moving that morning, the facility was collecting real-time data on the components.
Giant metal rings, called adapter plates, sat in piles near the concrete testing wall; a few more were stacked on top of it. Some are uneven, to hold the blade at a specific angle for tests.
The plates also function like a phone adapter, explained Rahul Yarala, executive director of the facility. Blade manufacturers don’t always use the same design at the root, the part of the blade that connects to the generator. The plate helps connect the root to the testing wall.
In another area were stacks of wooden “saddles” — specially cut contraptions that hug the blade at a particular section and connect to cranes that create the heavy loads.
The facility is one of several checks that developers go through to certify their blades.
MassCEC is accredited to test a specific international standard: full-scale structural testing of blades. But blade companies must also meet international standards for manufacturing, including quality management.
MassCEC’s testing is focused on the design and innovation stage of blade development, before the blades are manufactured at a large scale.
Sometimes companies have the facility test a section of a blade, but that’s typically when they’re not as far along in the design. Most times, the center is testing blades when a company is 80% to 90% finished with its design, Yarala said.
According to MassCEC, its Boston blade-testing facility is the largest in North America. Other existing and upcoming blade testing facilities are located in Germany, Denmark, the United Kingdom and China.
Names for the facility’s different tests include edge fatigue, in which the blade is moved side to side for up to eight weeks; and flap fatigue, in which a machine called a hydraulic actuator applies the load up and down. One can envision the movements like the tails of a whale and a shark moving through the water.
Generally, a company will pay about $600,000 to $800,000 to test one blade, Yarala said. The program simulates about 25 years of operation.
Costs can increase depending on the scope of testing. If a company wants the center to push the blade to failure (which means the giant blade breaks), the center’s equipment will get damaged in the process.
An agency spokesperson did not respond to a question about what failure can look like in testing, but videos from other facilities show the blade buckling, cracking, or its layers (held together by adhesive) breaking apart.
The center started by testing 150-foot blades for land-based turbines. More than a decade later, it tests blades up to about 295 feet long for the offshore industry. The heaviest blade the center has tested was about 99,000 pounds, or the weight of about nine elephants.
Recent federal funding has allowed the center to upgrade some of its equipment to test even longer turbines (though they may still need to be cut down to fit inside).
To date, they’ve tested about 55 models.
“It’s a very complicated process to design and build a blade,” said Yarala. “Testing it is complicated and time-consuming … Everyone, including our customers, are doing their best.”
Testing GE’s Haliade-X blade
When GE’s Haliade-X blade arrived for testing in 2019, the tip was cut off: the 351-foot component was too long to fit into the facility that maxes out at testing 295 feet.
Opponents of offshore wind development have attributed, without evidence, this truncated testing to the blade failure at the Vineyard Wind project over the summer.
But experts explain cutting the blade for testing does not significantly impact the testing of its reliability in the field.
“I agree that, in general, the blade tip is not typically of high importance during testing,” said Joshua Paquette, researcher at the federal government’s Sandia National Lab in New Mexico, in an email. Paquette, an engineer by training, leads a blade collaborative that conducts research on blade reliability and issues.
“As long as loading is applied correctly to the blade in both the ultimate load and fatigue tests, and the design margins are high enough in the outer part of the blade, it should be acceptable to remove some of the blade tip to facilitate a test,” he wrote.
Another industry blade expert based in the U.S., who spoke on background, said that with the exception of a lightning strike, he had never seen a blade fail structurally at tip, and that is because the loads are very light there.
What typically happens at the tip is called “leading edge erosion,” the expert said, but that happens over a number of years of wear and tear.
He also noted MassCEC did not test the exact blade that failed at Vineyard Wind. Rather, they tested a design prototype of the blade, assuming the blades subsequently manufactured would be made in exact accordance to the design, which was certified by a separate entity, Norwegian firm DNV.
Paquette said the increasing blade size does “bring up an important point about the difficulty of performing tests on these large structures.”
“The testing of a single blade requires specialized facilities and takes many months,” he said. “There are well-developed standards for wind blade testing … and there is much in the way of ongoing research in the U.S. and elsewhere on the topic of improved test methods.”
The Light requested testing information for the Haliade-X blade prototype from MassCEC, but the quasi-governmental agency says it is proprietary information that cannot be shared. (All visitors to the center are also required to sign a release form that assures confidentiality of “confidential business information,” and precludes the taking of some photographs.)
Yarala, the testing center’s director, would not speak specifically on the Haliade-X testing (or any specific blade, citing confidentiality concerns). He did, however, speak generally about testing blades, stating the tip section of the blade is less structurally challenging than the root.
He also noted other industries cannot and do not test items — think a bridge or the aerospace industry — at full scale, but use the data collected at sub-scale to confirm it will work.
A MassCEC spokesperson said its testing is part of a multi-step testing and certification process, which can include data from other facilities.
The spokesperson said the blade company’s engineers will account for the blade cutting in the testing specifications it provides to MassCEC. The agency returns the data it collects, but is not the blade certifier for either the design or the manufacturing.
Expansion in the works
Massachusetts built the testing center as part of its effort to take a leading role in the offshore wind industry. At the groundbreaking ceremony for the center in December 2009, U.S. Sen. Ed Markey stressed that goal.
“New England winds have tested the wills of sailors and citizens for centuries,” Markey said. “Now we will be taking the lead in testing and developing the wind turbines that will help power our nation in the 21st century. This new clean energy facility will help ensure that the Bay State has a front row seat for the clean energy revolution.”
Now, state leadership seeks to retain that front row seat.
As turbine components have quickly grown, they have outgrown the 13-year-old Charlestown facility. And just as MassCEC is expanding its staging terminal in New Bedford, built in 2015, to account for increased capacity needs, the quasi-state agency is in the design and planning stage of expanding the testing center.
A MassCEC spokesperson said the expansion of the testing facility will help the agency “remain competitive” with the expected growth in blade size.
At the beginning of the year, Massport solicited bids for an estimated $80 million expansion project to extend the length from the testing wall by almost 280 feet, to about 575 feet.
A spokesperson with Massport said project design will start next month and continue through most of 2025. Construction will likely begin in 2026 and take around 18 months.
Email Anastasia E. Lennon at alennon@newbedfordlight.org.
Thank you for such an in depth and informative article. You indicated the cost of testing runs $600,000 to $800,000 per blade. Given the number of additional blades requiring a test before electricity can be produced, the overall cost will be increased by several million dollars. How is that going to impact GE’s operation and, more importantly, the prices to consumers?
It’s in the contracts.
You haven’t been reading them?
Passive aggressive?
Unless these blades are tested in the harsh North Atlantic Ocean for an entire year.
It really doesn’t matter if they test the blades in a simulated environment it will never tell us whether or not these blades will hold up to the real world environment period.
The late Edgar Gunter, a mechanical engineer who was at the forefront of rotor dynamics research and engineering support — including for the NASA space shuttle program and the petrochemical industry — suggested the cause of the blade failure was not a material bonding problem, but rather “a classical torsional fatigue failure of the blade at the base.”
Besides sharing his analysis with the federal agency, Gunter shared his theory on the New England Offshore Wind Discussion Group Facebook page earlier this month, prior to his death on Aug. 14.
He noted that the blade was based on a design that aims “to develop large blades that could bend and flex under each rotation to reduce stresses” and stated that the fiberglass shell “did not have any reinforcing carbon fiber added.”
“Carbon fibers cost 15 times more than fiberglass and also require extremely toxic epoxy glues for the bonding,” wrote Gunter, who was a fellow with the American Society of Mechanical Engineers, president of Rodym Vibrations Analysis, and professor emeritus in the department of mechanical and aerospace engineering at the University of Virginia.
He said carbon fiber has “15 times of strength of fiberglass.”
On a more technical level, Gunter posited in his Aug. 2 posting, the blade “encountered a torsional divergence.”
“This terminology was developed by NASA to explain the failure of flexible propeller blades. As a blade rotates and flexes the aerodynamic forces on it increase until the endurance limit of the blade is met and it fails. This is just one of the unstable flutter modes that these large flexible blades can encounter,” he wrote.
Gunter suggested that all of the blades should be analyzed for aerodynamic flutter stability before any more are installed in offshore turbines. He also suggested that a scale model of the blades needs to be tested in a NASA wind tunnel before installation.
In 1997 LM Glassfiber had these same torsion problem
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LM Wind Power (formerly LM Glasfiber is a Danish manufacturer of wind turbine blades)
About LM Glassfiber, Denmark torsion ( blade cracks )
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Article: 1997 Windpower Monthly
Blade cracks signal new problem, preventative investment needed on turbines with large LM blades
https://www.windpowermonthly.com/article/958000/blade-cracks-signal-new-stress-problem-preventative-investment-needed-turbines-large-lm-blades