Defence chiefs say a planned wind farm could stop the RAF from spotting enemy planes bound for Britain.
The MoD says a wind farm planned for Hill of Braco, Aberdeenshire, would hurt a nearby radar station’s ability to “detect threats to UK airspace”.
The ministry’s written objection to the plans come as complaints about the project have soared to more than 1000.
Defence chiefs say the proposed eight 100-metre-high turbines will obstruct the radar of RAF Buchan, based five miles away.
An MoD spokesman said: “This would compromise the capability of Air Defence operation staff to detect threats to the UK airspace and control aircraft at range.
“The MoD also said the turbines would cause “unacceptable interference” to a Met Office radar station at Hill of Dudwick nearby.
Locals have argued the area already has too many wind turbines and would damage a site of scientific interest called the Moss of Cruden.
But the MoD objection could kill off the bid to build the windfarm, which would have a 20MW capacity. The RAF station houses a radome which can track aircraft entering the UK’s airspace, and was first opened in 1952.
Wind energy developers PNE Wind UK, who are behind the bid to build the farm, say they will consult with the MoD about how it will affect radar.
A spokesman said: “We are actively working to address the concerns that have been raised in the representations to Aberdeenshire Council which, in many cases, have been considered in detail during the development process and are included in the planning application.
“The impact of turbines on radar is something we are aware of and we will continue to discuss with the MoD how to ensure there will be no detrimental impact on radar installations if the Hill of Braco Wind Farm is consented.
“We know that visual and landscape impact is a key local consideration and have taken this fully on board as we have developed the size and layout of Hill of Braco.
“We believe the proposals we have submitted to Aberdeenshire council are sensitively designed to ensure this impact is carefully managed.”
He continued: “We remain committed to delivering a project that will contribute towards national energy needs and provide a community fund of £100,000 a year.”
PNE said there was local support for its plan, with a phone poll of residents finding 43% were in favour.
The company said out of 346 households questioned only 30% were against and 21% neutral.
Campaigner Michele Emslie , from Blackhills, said: “Residents feel that talk of community benefits prior to a planning application decision is extremely manipulative and bad conduct. The damage this development will do far outweighs any benefits.”
The plans will be brought before the council’s Buchan area committee in the coming months.