Vineyard Wind Turbine Had Non-Operational Lightning Protection System When Struck

The damaged Vineyard Wind turbine that was struck by lightning last week had a non-operational lightning protection system due to the blade failure it suffered last July, according to the Bureau of Safety & Environmental Enforcement (BSEE).

The federal agency on Wednesday stated that it is overseeing the assessment and response to the lightning strike, and is requiring Vineyard Wind to conduct a "comprehensive assessment" to determine the extent of the damage done to the turbine.

"Overflights and on-scene vessels did not find initial debris in the water," a BSEE spokesperson said. "The turbine’s lightning protection system was not operational due to the July 13, 2024, blade failure. All other wind turbines are equipped with lightning protection."

While there was some initial confusion on the timing of the lightning strike, BSEE stated that it occurred on Friday, Feb. 28th. Vineyard Wind notified BSEE and the town of Nantucket about the situation on Sunday, March 2.

It was the same turbine - known as AW-38 - that had one of its three blades snap into thousands of pieces last July 13th, sending large amounts of fiberglass and foam debris onto Nantucket's shores, which forced the town to close all south shore beaches for a full day and prompted BSEE to suspend the project. While Vineyard Wind had previously removed the large pieces of the blade that were left dangling from the turbine rotor after the failure, the nub of the damaged blade remains attached at the 12 o'clock position on the turbine.

In a statement issued Sunday, Vineyard Wind claimed there was no impact to the nacelle or turbine structure from the lightning strike, and that after deploying both aerial and maritime resources "there is no indication of debris from this event.”

On Wednesday, the Select Board heard from several residents and others who raised concerns about the lightning strike, as well as the delay in notification to the town about the incident.

"The town of Nantucket wasn't notified until Sunday, three days later, and only after the news was widely spread on social media," said offshore wind critic and Select Board candidate Mary Chalke. "Did the town of Nantucket take action at any time to warn citizens of possible debris on the beach? Were warnings issued by the town of Nantucket to our fishermen and recreational boaters that there may be debris in the water? Again, Vineyard Wind failed to promptly notify the town of Nantucket of an incident, of a polluting accident, at the wind farm. What actions, such as withdrawing from the Good Neighbor Agreement, will be taken by the town? Has the board taken a straw poll among its members so the public can see whether the board wants to exit the Good Neighbor Agreement?"

According to DNV, a global assurance and risk management company, "lightning damage is the single largest cause of unplanned downtime in wind turbines and the most common insurance claim filed by wind farm owners."

In December 2022, DNV issued an independent certification for Vineyard Wind's Haliade-X turbines based on a "rigorous third-party certification process" and testing conducted on a land-based prototype.

Based on the growing size of offshore wind turbines - with Vineyard Wind's 853-foot Haliade-X model being the largest in the western world - DNV stated that "lightning protection is becoming more and more important for all stakeholders in wind power industry."

According to Vineyard Wind's construction and operations plan, all of its wind turbines were to be equipped with lightning protection.

The German technology firm the Schunk Group, which specializes in climate technology and manufactures lightning protection systems for wind turbines, states that "When lightning strikes a wind turbine, currents of several tens of thousands of amperes flow within fractions of a second - even maximum values of 200,000 amperes have already been recorded. The electrical voltage reaches several million volts. If the lightning protection now fails, the consequences are serious: Not only can overcharge damage occur in the electrical control system, but the rotor blades can also snap off. And not only that. Since the air temperature inside the lightning channel rises abruptly to several tens of thousands of degrees Celsius, fires easily start."