There are currently just under 30,000 onshore wind turbines in Germany. Globally, installed wind power amounts to more than 800,000 megawatts, meaning that the world’s wind farms can already generate twice as much electricity as nuclear power plants. However, this is still nowhere near enough to fully achieve the energy transition. In Germany alone, the new Renewable Energy Sources Act (EEG) sets out plans to install onshore wind farms with an output of 71,000 megawatts by 2030. Taking into account the decommissioning of old farms, this equates to a doubling of the previous stock.

As such, new land has to be made available, but this is often thwarted by resistance from the local population. One issue in this regard is wind farm lighting, which nearby residents often see as a nuisance. Wind farms have to be fitted with nighttime lighting in order to make them visible to aircraft and helicopters in the dark. In Germany, for instance, this became a legal requirement at the end of 2022 for all wind turbines taller than 100 meters, with similar rules in place in many other countries.

HENSOLDT offers a solution to this problem with its AIR SENTINEL, a system that automatically detects approaching aircraft, only activating the lighting when the aircraft enter a predefined danger zone. Otherwise, the wind farm remains dark, with no flashing lights or other disturbances.

This can significantly increase acceptance rates among residents, thereby making new sites available for the necessary expansion of the wind energy infrastructure. In addition, HENSOLDT has also optimized its air traffic control systems at airports so that they can more easily distinguish between an unauthorized aircraft and the electrical noise of wind farms. This means that wind farms can also be built in closer proximity to airports, thus making further potential locations available for the energy transition.

The AIR SENTINEL early-warning system uses existing HENSOLDT technology to locate low-flying aircraft. The system receives the transponder signals emitted at various frequencies by all aircraft and helicopters flying at night. Each aircraft is logged with a time stamp.

Weighing just four kilograms, AIR SENTINEL is able to cover a radius of 25 kilometers all around the farm, up to an altitude of 1,000 meters. With a service life of roughly 20 years, it is equally suitable for both individual wind turbines and entire wind farms. AIR SENTINEL is installed on the wind turbines themselves and can easily be retrofitted to existing farms. This turnkey solution does not require any significant maintenance and can be easily updated to reflect new demands or legal requirements via tablet. Military-grade manufacturing ensures long and reliable operation.

AIR SENTINEL has been successfully tested at a German wind farm. The tests were carried out by Parasol GmbH & Co. KG, a company specializing in demand-controlled nighttime lighting for wind parks. As HENSOLDT’s main contractor, Parasol is the first company in Germany to be awarded distribution rights for the AIR SENTINEL and will be responsible for the installation, commissioning, and maintenance of the system. Series production of AIR SENTINEL is already underway. In January 2023, Parasol installed and commissioned the system at two wind farms in northern Germany.

AIR SENTINAL detects approaching aircraft ...

... and activates the lighting of wind farms ...

... as needed.

Air Surveillance Radar – No Wind Farm Shadows Air surveillance radars provide airports with an early warning of unauthorized and unidentified aircraft. The combined primary and secondary radar ASR‑NG (Airport Surveillance Radar Next Generation) from HENSOLDT is able to reliably identify smaller aircraft that do not identify themselves using transponder signals, even in the typical “radar shadows” of wind farms. Thanks to its special signal processing technology, it ensures wide-range air surveillance and automatically eliminates the interference of wind turbines. In 2022, HENSOLDT modernized the ASR‑NG air traffic control system of Austrian air traffic control provider Austro Control GmbH at Vienna International Airport accordingly.