Power generation has been halted at the 396 MW Merkur offshore wind farm in the German North Sea due to turbine issues, the green energy investment trust The Renewable Infrastructure Group (TRIG) said on Monday.

The London-listed TRIG said that routine inspections had identified signs of stress fatigue on certain areas of the support structure of the helihoist on some of the 6MW wind turbines manufactured by GE.

“Generation at the wind farm was paused as a precautionary safety measure whilst the root cause of the issue is being investigated,” TRIG said in a statement. 

It added that the turbines are under warranty and service contract with GE, that supplied 66 wind turbines producing enough power for almost half a million German homes. Contractual provisions also include a mechanism to protect lost revenue whilst turbines are not operational, subject to a cap. TRIG said it does not currently expect that the cap will be exceeded.

The first batches of turbines have been brought back online, in consultation with the authorities, and work is underway to identify and put in place a solution that will allow the wind farm to resume operations.

The Merkur offshore wind farm, located 45 km from Germany’s Borkum Island, is owned by the Dutch pension group APG 64%, TRIG 25% and InfraRed 11%.