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Wind farms and radar obstruction

By: jpoley
Are the answers to our energy woes blowing in the wind? Maybe. Wind farms are an amazing potential for clean renewable energy, but like all great technologies, there are complexities that need to be considered. First, wind farms must be sited in an area with the best wind to achieve the best results. Unfortunately, the windiest places don’t always play nicely with the locals. Some residents have aesthetic concerns about the giant spinning blades on their horizon. There are also concerns about birds and bats being minced as they innocently fly through the area. Others argue that the benefits of the clean power have less of an effect on our winged friends than current non-clean power sources. Offshore sites seem like a reasonable solution until we bring up another winged friend—the airplane. Airplanes are one of the lifelines of modern civilization and there are thousands in the air at any given moment. Strategically placed radar systems play the vital role of keeping track of them for security and safety reasons. But what many people don’t realize (or didn’t realize until recently) is that wind farms can directly affect radar system performance and their ability to detect airplanes. In simple terms, radar systems bounce radio frequency signals off objects to detect them. They determine the speed of the object based on how the signal comes back shifted in frequency (Doppler shifted). Everyone has experienced the Doppler Effect when they’ve heard a siren drive past. The radar systems are typically smart enough to filter out unwanted signals based on magnitude of the shift in frequency. The issue with wind farms is that the large rapidly moving blades of the turbines are basically returning signals to the radar that are indicative of an aircraft. Thus, an aircraft flying parallel to the farm’s spinning blades can become nearly impossible to detect because the blade tips are moving at nearly aircraft velocity. This poses a significant risk in security. Imagine the consequences of a huge wind farm placed in the Atlantic Ocean that provided 150 million people with clean power but completely blinded the Eastern Seaboard to all incoming air traffic. I don’t think the expression ‘ignorance is bliss’ was ever meant to be applied to anything in the sky. Obviously, there are many factors in determining the level of interference, including the frequency used by the radar, the speed of the aircraft and the orientation of the situation. With some planning and radar simulation before a wind farm site is chosen, wind farms around the world could blow past all other sources of clean energy in our future. Airplane over wind farm If you would like more information on the technical aspects to this problem, please contact Greg Haun ( or learn about our Electronic Systems Software .
Posted: 10/19/2010 7:11:43 PM