A significant technological system change has been implemented in Lower Austria for the marking of wind turbines. The new Gnadendorf-Stronsdorf wind farm is the first to use the so-called demand-based night-time marking (BNK) system.
This technology replaces the previously mandatory continuous red flashing lights, which served to ensure air traffic safety, with an intelligent control system. The warning lights on the wind turbines will remain off during the night and will only be activated when an aircraft is in close proximity. With this measure, the state of Lower Austria is responding to long-standing demands from the local population and aims to increase public acceptance for the further expansion of wind energy.
The technical implementation is based on an innovative system from the Austrian air traffic control provider Austro Control. By linking radar data and aircraft information, the system detects in real time whether an aircraft or helicopter is entering a defined protected area. This area encompasses a radius of at least eight kilometers around the installation and extends to a height of 600 meters above the highest point of the obstacle. To ensure the uninterrupted safety of rescue and emergency flights, pilots or control centers can also manually activate the lighting remotely if necessary. This step was made legally possible by an amendment to the air traffic regulations, which now explicitly permits the use of radar-based obstacle lighting systems.
The energy supplier EVN plans not only to equip new projects with this technology but also to gradually retrofit existing wind farms. This presents operators with technical challenges, as older systems often require extensive modifications to their control electronics to establish a compatible interface with the Austro Control system. Furthermore, retrofitting existing systems often necessitates a new permitting process according to current standards. Despite these efforts, EVN sees this measure as a necessary component of its growth strategy, which aims to increase installed wind power capacity to 770 megawatts by 2030.
Deputy Governor Stephan Pernkopf and President of the State Parliament Karl Wilfing emphasized the importance of the new regulation for the quality of life in rural areas, particularly in the Weinviertel region. The elimination of continuous flashing lights is intended to significantly reduce the burden of light pollution at night. In Lower Austria, approximately 180 new wind turbines have already been approved under the current coalition agreement between the Austrian People's Party (ÖVP) and the Freedom Party of Austria (FPÖ). The introduction of demand-based nighttime marking is considered a crucial compromise to make the massive expansion of energy capacity more acceptable to local residents.