On-demand night-time marking: no more continuous flashing at night

8. Mai 2020

Photo Copyright: RECASE

Wind turbines should only light up red at night when an aircraft is in the vicinity of a wind farm. The so-called “Bedarfsgesteuerte Nachtkennzeichnung“ (BNK: German term for on-demand night-time marking) can considerably reduce the flashing at night. This is intended to increase public acceptance for the expansion of wind energy. At the same time, on-demand night-time marking also minimizes the impact on the environment and local residents.


An essential component of a BNK is the technology for recording aircraft during the night hours. Until now, only radar-based systems have been approved. However, as these systems are very expensive and not always easy to implement, the Federal Cabinet approved an amendment to the General Administrative Regulation on the Marking of Aeronautical Obstacles (AVV Marking) on 4 March 2020. This allowed another safe and cost-effective alternative: the use of transponder signals.

The obligation to retrofit an BNK system (Section 9 (8) EEG 2017) applies to new and existing turbines. Legislators only provide for a few exceptions, thereby increasing the pressure on the sector through short implementation deadlines which poses immense challenges to operators, operations managers and service companies. At the same time, operators are facing considerable financial damage if they breach this obligation. At present, the implementation deadline, already extended by the Federal Grid Agency, gives them time until 30.05.2021.


wpd windmanager GmbH & Co. KG has been following the subject of BNK for some years and playing an active role in technical committees and working with manufacturers to design the BNK system as well as to develop overall technical concepts that are cost-efficient.

„A structured approach is essential.“

“The complexity of retrofitting an BNK system requires a structured approach”, explains Jonas Lesch, Technical Management at wpd windmanager. “Only by taking exact stock of the project and knowing the technical requirements in the wind farm is it possible to identify the measures needed and the potential to reduce costs during installation.” In the process, wpd windmanager can call on its many years of experience, a large network and in-depth know-how in order to implement the specifications of the new regulation.


Copyright: Dark-Sky


“Due to the tight implementation deadline, operators can expect service and BNK providers to be at the limit of their capacity”, states Till Schorer, Sales Director at wpd windmanager. “We are therefore working independently, and specifically for each wind farm in order to identify the right overall concept for that particular farm while keeping a watchful eye on the costs.” Good preparation and an early start will speed up implementation and lessen the risk of delay.

„Preliminary tests for 1,500 turbines already completed.“

wpd windmanager has already conducted preliminary examinations on around 1,500 turbines in over 300 wind farms. The operations manager can support operators in all the steps required for implementation – an offer that initially applies exclusively to the company’s own customers.

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