The U.S. Air Force is threatening to halt construction of a 845-megawatt wind farm in eastern Oregon that would be the world’s largest wind project, citing concerns that the wind turbines would interfere with a nearby military radar station and its ability to detect radar images. Rotating wind turbine blades could impart a Doppler shift to any radar energy reflecting off the blades and cause false images or interference. This has impact on the location of future wind farms but issues remain on how to resolve this problem.
The U.S. Air Force is threatening to halt construction of a 845-megawatt wind farm in eastern Oregon that would be the world’s largest wind project, citing concerns that the wind turbines would interfere with a nearby military radar station and its ability to detect radar images. Rotating wind turbine blades could impart a Doppler shift to any radar energy reflecting off the blades and cause false images or interference. This has impact on the location of future wind farms but issues remain on how to resolve this problem.
!ADVERTISEMENT!A wind farm is a group of wind turbines in the same location used for production of electric power. Individual turbines are interconnected with a medium voltage power collection system and communications network. At a substation, this medium-voltage electrical current is increased in voltage with a transformer for connection to the high voltage transmission system.
Wind farm siting can be highly controversial, particularly when sites are picturesque or environmentally sensitive, such as having substantial bird life, or requiring roads to be built through pristine areas. These areas are generally non-residential due to the noise concerns and setback requirements. And now there are radar concerns.
Easy access to the power grid must be taken into mind. The further from the power grid, there will be need for more transmission lines to span from the farm directly to the power grid or transformers will have to be built on the premises depending upon the types of turbines being used.
As a general rule, wind generators are practical if the wind speed is 10 mph or greater. An ideal location would have a near constant flow of non-turbulent wind throughout the year with a minimum likelihood of sudden powerful bursts of wind.
Concerned that the blades of the 338 massive wind turbines might interfere with radar signals when positioned at certain angles, the Department of Defense moved to reject a Federal Aviation Administration permit. Construction of the $2 billion project (which the Pentagon called a hazard to air navigation) is scheduled to begin in two weeks. Developers say that significant delays will likely kill the project because it will lose eligibility for federal stimulus dollars if construction does not begin soon. Obama administration officials and wind energy lobbyists are now working to resolve the Pentagon's concerns and clear the way for the Oregon project.
What has not been resolved is how close is too close and whether there are any other alternate solutions to the radar clutter.
Some studies in the United Kingdom and elsewhere show that while wind turbines can cause clutter on radars, there are engineering solutions that can be implemented or should be explored further.
A June 2003 study from the British Department of Trade and Industry concluded that there are hardware and software mitigation efforts that can be implemented to reduce or eliminate the effects of wind turbines on radars. These solutions include adding radars, adding filters to the radar software, or altering the layout of a wind project.
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