In the Netherlands, onshore wind turbines with a tip height of over 150 meter are required to be fitted with obstruction lights, much to the annoyance of the local community. However, the red, flashing obstruction lighting on the turbines of the onshore wind farm Krammer is expected to be switched off soon. This is made possible by the use of a transponder-based detection system. Windpark Krammer is serving as a test site for this.
Earlier this year, Krammer Wind Farm was designated as the national test site for the transponder-based detection technology. The preparations for this have now been completed. Last week, engineers installed detection equipment and new lighting on the turbines that are suitable for this transponder technology.
The system has now been tested with a drone and a final flight test will follow. Subsequently, the Human Environment and Transport Inspectorate (ILT) will check the results of the flight test and if there are no obstacles, Windpark Krammer may apply the technology and the lights can be switched off as much as possible at night.
This process is expected to be completed within a few weeks. The obstruction lighting will then only switch on incidentally, when an aircraft is approaching the wind farm.
“We are extremely pleased to be able to report this at last. There was very intensive cooperation with various authorities to get this done. And we thank the local residents for their patience. The fact that Krammer is now the first wind farm that can switch off its lights at night is a fantastic step forward.” – Marlies Sikken, Director of Windpark Krammer
Radar technology versus transponder technology
This is not the first test to be carried out at the wind farm to prevent the flashing, red lighting at night. In 2018, Krammer was the first wind farm in the Netherlands to conduct a pilot with a detection system based on radar technology. With radar technology, a radar in the vicinity of a wind farm detects when an aircraft approaches. The results showed that radar technology works and is safe.
The intention was to make a new radar of the Ministry of Defence suitable for this application. This would make it possible to switch off the obstacle lighting on wind turbines at night throughout the province of Zeeland. But the introduction of the system turned out to be more complicated than expected, both technically and organisationally.
National project group
Abstruction lighting is often a cause of social resistance to wind turbines. A national project group, in which Windpark Krammer and other bodies such as ILT, the Netherlands Enterprise Agency (RVO) and various ministries work together, has been set up to deal with this. The project group has for years been searching jointly for solutions and techniques to switch off the annoying permanent lighting on wind turbines at night.
In Germany, transponder technology has been approved. Following research by the project group, this technique appears to be less complex to apply and therefore more accessible for existing and future wind farms. Partly based on the experiences in Germany, Windpark Krammer decided earlier this year to abandon radar technology once and for all and to opt for transponder technology. Krammer, in collaboration with the project group, is now taking concrete steps in this process.
Transponder technology makes use of the presence of a transponder in aircraft. A transponder continuously transmits a signal and a receiver on a wind turbine picks up the signal. But this system is only safe if all aircraft flying in the dark are equipped with a transponder. This transponder obligation has now been in force since 1 October. That was the last step needed before this system could also be used in the Netherlands.
Krammer Wind Farm
Krammer Wind Farm, located on the Krammer locks in the province of Zeeland, comprises 34 Enercon E-115 wind turbines with a capacity of 3 MW each. It is the largest citizens’ initiative for sustainable energy in the Netherlands. The project in an initiative of the 5000 members of the energy cooperatives Deltawind and Zeeuwind. Together, they own 60% of the wind farm. The other 40% of the shares are owned by Kallista Energy. The wind farm has been fully operational since 29 March 2019. Source: Windpark Krammer