Offshore Wind Turbine Failure Prompts Calls for No Sail Zone

turbine failure prompts no sail zone around wind farms — Operating for nearly a decade the wind farm in Denmark where the failure took place has 111 turbines (Anholt file photo)

Ørsted, one of the leading developers of offshore wind farms, and turbine manufacturer Siemens-Gamesa are investigating what caused a turbine failure at one of Europe’s older and largest offshore wind farms. At the same time, the companies advised that a “no sail zone” should be established around eight other wind farms in the UK, Germany, and Denmark as a precaution.

The companies called for the action while reporting that a rotor including three blades had separated from a nacelle of one of the offshore wind turbines at Anholt Offshore Wind Farm in Denmark. The debris was sent crashing into the ocean and while no one was injured the companies are advising caution while they investigate the cause of the failure.

“So far, the investigation has not pointed to a systemic cause of the issue, but we have taken this precautionary step as safety is our first priority,” said Ørsted in a prepared statement. “The assets continue to operate as normal with the relevant safety protocols, and customers in the relevant markets will not be affected.”

News of the incident however caused concern across the offshore industry and with investors in Siemens-Gamesa. While there have been other failures with offshore turbines, investors possibly based on the magnitude of the number of turbines involved in the cautionary announcement sent the stock price of the turbine manufacturer down by more than eight percent.

Anholt Offshore Wind Farm was commissioned in 2013 and consists of 111 Siemens-Gamesa 3.6 MW wind turbines. With a generating capacity of 400 MW, the farm became the largest in Denmark and the world's third-largest offshore wind farm when it entered service. It is located in the Kattegat strait between Jutland and the island of Anholt covering an area equivalent to nearly 34 square miles. The turbines were described as each weighing up to 205 tonnes for the nacelle and 18 tonnes per blade.

“We are investigating the cause of the incident, and as an extraordinary precautionary measure, we are requesting the relevant authorities to establish ‘no-sail zones’ at all of our offshore wind farms that use the same turbine as at Anholt,” Ørsted said.

A widely used turbine, Ørsted reports that besides Anholt, it is installed at another wind farm in Denmark, as well as one in Germany and five locations in the UK. The no sail zone applies to each of these farms while the investigation is ongoing.