A massive offshore wind farm planned for the Moray Firth could hamper air traffic operations, a study has found.
Developers of a £3 billion project to construct up to 277 huge turbines have examined the environmental impact.
They found the turbines may be “indistinguishable” from aircraft on radar screens at the air traffic control centres at RAF Lossiemouth and Aberdeen Airport.
The wind farm could also affect evacuation and transfer flights to oil and gas platforms near the development, the report adds.
Developer Beatrice Offshore Windfarm Ltd (Bowl) – a consortium of SSE Renewables and Repsol Nuevas Energias UK – said the wind farm would have between 142 and 277 turbines, depending on their size.
It is planned for nine miles off the coast of Caithness and would be visible from as far afield as Orkney and Moray.
However, the consortium’s environmental statement admitted the wind farm could potentially affect radar systems at RAF Lossiemouth and Allans Hill, near Fraserburgh, an air traffic control site used by Aberdeen.
It states: “This is due to the fact a large proportion of the turbines are theoretically visible to both RAF Lossiemouth and Nerl (air traffic control) Allans Hill.
“The theoretical visibility of turbines will cause unwanted radar returns to be presented on the primary source radars and will likely hamper an air traffic controller’s ability to distinguish aircraft returns from those created by the wind-farm turbines, known as clutter.”
Possible solutions being considered include a new radar system and upgraded holographic radar.
The consultants who prepared the statement added: “A potential effect was identified for helicopter operations to offshore oil and gas platforms in the Moray Firth.
“This is due to the effects on both visual and instrument approaches to the platforms, decreasing the ability of helicopters to reach the platforms for both evacuation and personnel transfer purposes.”
The minimum safe altitude for flights in the Moray Firth in bad weather would have to be raised by 200ft to allow space above the turbine blades.
An Ministry of Defence spokesman said wind turbines could affect military operations and it was “crucial” its weapons, firing ranges and navigation were protected.
He added: “The MoD fully supports the government’s renewable energy policies and targets. However, wind turbines can have detrimental effects on MoD operations and assets. The MoD ensures that any developments, both on and beyond the defence estate, do not adversely affect military operations and assets.”
The spokesman added that the MoD was in discussions with the wind-farm developer.
A National Air Traffic System (Nats) spokeswoman said it was too early to tell whether her organisation would lodge an objection.
She said: “The movement and the altitude of the [turbine] blades can cause clutter on the radar screen, which can interfere with the controllers’ ability to identify the aircraft passing through the area.”
A Bowl spokesman said: “We have been in regular consultation with the MoD, the Civil Aviation Authority, National Air Traffic Systems and offshore platform stakeholders from the outset.
“We will continue to consult all relevant agencies throughout the consenting process.”