The core of a wind turbine is the rotor star, consisting of three rotor blades and the hub to which they are attached. The rotor blades “catch” the wind and pass the wind energy on to the generator via the rotation of the rotor and the associated internal drive train.

In addition to various electrical control cabinets, the oil and grease supply, the hydraulic modules, the blade pitch control, the wind tracking system, etc., the nacelle also houses the heart of the power generation system: the drive train. The drive train, at the end of which is the generator, is driven by the rotor blades. A generator is an electrical machine that, like a dynamo, converts kinetic energy into electrical energy. 

A winch platform is mounted on the nacelle. People can abseil onto this from the helicopter. This is necessary to reach the facility even in bad weather conditions when a ship transfer is not possible. Especially for rescue purposes, accessibility by helicopter is essential. 

The tower contains several platforms that can be reached via a ladder. The switchgear, the converter system and the transformer are located on these platforms. There is also a service lift that can transport both materials and personnel from the bottom to the top of the nacelle. The energy generated by the generator is fed downwards via the so-called loop cables in the tower.

The boat landing allows personnel to access the facilities. For a transfer, the service boat presses the specially designed bow to the boat landing, where a staircase up to the outside platform is attached.

The tripods and three 30–40 m steel tubes driven into the seabed anchor the wind turbines to the seabed.

Operation, Maintenance and Repair

The Trianel Wind Farm Borkum is in operation day and night. To ensure that it can be managed around the clock, nearly 30 employees of Trianel GmbH are on standby to look after the operation, maintenance and upkeep of the wind farm. Together with our service provider Siemens Gamesa, this ensures the availability of the wind farm.

Switching On and Off the Wind Farm
The turbine switches on at a wind speed of 4 m/s, which corresponds to wind force 3. At wind speeds of over 25 m/s, i.e. at wind force 10, it switches off automatically to prevent damage. It reaches its full power – i.e. the entire 5 MW per turbine – at a speed of 13 m/s and above. At that speed, the turbine runs at full load.


The 24/7 manned control room handles, among other things, remote fault clearance, fault analysis and preparation of maintenance stops.

On-site fault clearance is carried out by the Service Operations Vessel (SOV). This is a hotel ship that travels back and forth between wind farms. For two weeks, it is the home of the technicians, who work in shifts to carry out necessary work in the wind farms. Smaller Crew Transfer Vessels (CTV) are then used to transport the technicians to the individual turbines.

In high waves, however, the CTV cannot land. In this case, the wind turbine can be approached by helicopter. A winch platform is mounted on each nacelle, onto which people can abseil from the helicopter.

The Trianel Wind Farm Borkum itself cannot accommodate any people. As the park can be reached from the mainland within two hours, this is not necessary.

A live overview of each wind turbine is displayed via a dashboard. In case of an error message that cannot be rectified by the turbine itself or via remote control, the CTV brings the technicians to the turbine to carry out the fault clearance/repair work on site. Marine coordination also takes place via the dashboard that displays when a technician enters the turbine and when he has finished working.

Even when the turbine is not malfunctioning, preventive missions are carried out in the park, so-called preventive trouble shooting to work through open items that are not relevant to operation. The standard-compliant maintenance of the wind turbines is regularly checked/verified by an external inspection officer by means of a recurring inspection (WKP).

Maintenance and Emergency Management

An operation-specific turbine maintenance campaign takes place annually to ensure the safety and technical availability of the systems as well as to comply with legal requirements. From underwater to rotor blade inspection, specialised teams check the required items on a recurring basis.

Trianel Wind Farm Borkum is also prepared for emergencies: Each wind turbine has a shelter equipped with a survival kit. The SOV houses a fully equipped infirmary. In addition, injured persons can be brought to the mainland via helicopter rescue.