The Lüdersdorf wind farm is located in the municipality of Wriezen in Brandenburg, about 50 km northeast of Berlin. It consists of three Vestas wind turbines with a total nominal output of 11.6 MW. There are three airfields in the immediate vicinity.
Due to the legal obligation under the Renewable Energy Sources Act (EEG), the light:guard system for demand-controlled night marking (BNK) was installed. The BNK system uses transponder signals and multilateration to detect the position of flying objects. Only when an aircraft is nearby is the lighting of the wind farm activated. This reduces night-time light pollution while ensuring safety for air traffic.
For the analysis of the switching on and off times of the lights at the Lüdersdorf wind farm, six months from September 2024 to February 2025 were considered. The average light-off time was 92.61% and this despite high flight activity in the area due to the adjacent airfields. The proportion of light-on-time and error was minimal, which speaks for the high quality of the system.
Light:Guard GmbH has equipped the Lüdersdorf wind farm with demand-controlled night marking (BNK). The built-in light:guard system can boast light-off times of 93% over a period of six months.
Since 1 January 2025, the use of demand-controlled night marking (BNK) has been mandatory on wind turbines. The obligation results from the Renewable Energy Sources Act (EEG), and high penalties must be paid in the event of non-compliance. The regulation was introduced to protect people and nature from unnecessary light pollution from wind power.
BNK reduces the flashing of wind turbines to a minimum. To do this, the system monitors the airspace around a wind farm. If a flying object approaches, it cancels the suppression of the lighting and the red light flashes as before.
"The challenge here is to blink as little as possible, but at the same time to ensure enough safety for aviation," emphasizes Light:Guard Managing Director Willi Lehmann. "Especially in an area with a high volume of flights, the BNK system has to work very precisely in order to still achieve the desired effect and make the night dark."
This is exactly the case at the Lüdersdorf wind farm. The park is located in the municipality of Wriezen in Brandenburg, about 50 km northeast of Berlin. There are three airfields in the immediate vicinity.
The park is therefore particularly suitable as a case study. "We wanted to check: does the technology deliver what it promises? Do the nights get dark, even if there is a lot of air traffic?" explains Felix Weiss, Sales Manager of Light:Guard. "There is hardly any publicly available data in this country on how much flashing is actually reduced."
For the analysis of the switching on and off times of the lights at the Lüdersdorf wind farm, six months from September 2024 to February 2025 were considered. During this time, the nights are longest and there are more data points.
The average light-off time was 92.61% and this despite high flight activity in the area due to the adjacent airfields. The proportion of light-on-time and error was minimal, which speaks for the high quality of the ADLS system. Light:Guard relies particularly on multilateration for its system. The signal is received and processed by several receivers, so that the trajectory can be determined in addition to the exact location. This allows precise detection and the flashing to be switched on as needed.
The data confirms the obvious: the more you fly, the more the lights are on. The number of flights was particularly high in February 2025 with 828 detections. This means that the BNK system detected a flying object more than 30 times a night and then activated the flashing of the wind turbines. This results in a relatively low lights-off time of 80.29%.
However, this still means that only a fifth of the time is flashed, compared to the initial state without BNK. Daniela Beyer, Senior Investment Manager at the operator re:cap global investors ag, is also pleased about this: "With the demand-driven night labeling, we are not only fulfilling our legal obligation, but can also be a good neighbor for the local population. With Light:Guard, we have chosen the right partner. Thanks to their system, the nights in Lüdersdorf are dark."
re:cap and Light:Guard have been working together in the field of ADLS for several years. 14 re:cap wind farms have been equipped with the light:guard system in recent years.
"The Lüdersdorf wind farm was one of our first BNK projects. re:cap and we have done a lot of pioneering work on a new technology. It's great that we can repay the trust with good results," says Light:Guard project manager Jon Galdeano.
