Signs of hope on windfarm radar issues
Two recent developments may help overcome the problem of wind-turbine interference with aviation radar systems. £5.15 million is going into a research programme to protect Britain's air traffic control systems, and a 'stealth' turbine blade has been demonstrated in action.
The £5.15m R&D fund is made up of £1.6m from wind companies, £2m from the Crown Estate (which owns sites for offshore developments) and £1.55m from the government.
Aviation radar objections are a major reason why wind planning applications fail in the UK. NATS (formerly National Air Traffic Services) has lodged objections to over 5GW of wind farms currently in the planning system.
The 19-month research and development programme aims to mitigate the effects of wind turbines on the NATS En Route primary radar infrastructure. NATS technical experts will work with Raytheon Canada, the suppliers of the NATS systems.
An alternative to focusing on the radar system is to modify the turbines themselves. Technology firm Qinetiq has been working with Vestas Wind Systems on a five-year project to reduce the radar signature made by individual turbines to the point where they can be effectively ‘factored out’ of air traffic control and air defence systems.
Using a jointly designed 44m prototype turbine blade manufactured by Vestas, the technology has now been demonstrated at full scale for the first time at a wind farm in Norfolk.
The Stealth Turbine solution uses a portfolio of radar absorbing materials (RAM) that are integrated into the manufacturing processes for turbine components – blades, nacelle and tower – and which can be designed to operate at aviation and maritime frequencies. These include modified composites for nacelle and blades, and sprayable RAM coatings applied directly onto the tower and other static surfaces.
The Norfolk trial involved fitting the prototype stealth blade onto a Vestas V90 turbine. Qinetiq says radar cross section measurements showed significant reductions in line with expectations based on analysis and blade material measurements.