The UK is at risk of missing its Kyoto climate change targets because more than half of planning applications for wind farms are thrown out. The problem is that they interfere with air traffic control systems.
LONDON — The UK is at risk of missing its Kyoto climate change targets because more than half of planning applications for wind farms are thrown out. The problem is that they interfere with air traffic control systems.
In response, the UK's BAE Systems is pioneering technology that aims to reduce or even eliminate interference caused to air traffic radars by wind turbines' rotating blades.
The radar returns from the turbines' moving blades are typically similar in size to a light aircraft. To confuse the radar further, the tip speed -- though not that of the whole blade -- is just below the speed of sound, much the same as an aircraft.
On radar screens the signals generated show up as multiple objects that pop up and then disappear unpredictably. Air traffic control is affected so much that a wind farm built under a flight path would result in the closure of the airport.
Even if wind farms are located at the edge of the radar's 60-mile range, the interference is unacceptable to airport owners, local authorities and the Civil Aviation Authority.
BAE's technology works by analysing data normally hidden in a radar signal to build up a clearer picture of the object from which the signal came.
From the characteristics identified (such as which direction the object is moving in), fuzzy logic software is used to calculate the probability that it is a wind turbine.
If the balance of probabilities indicate that it is, the signals from the object are filtered out so that it does not appear on screen.
Originally developed by BAE for the military where it is was used to distinguish aircraft from large waves and flocks of birds, the technology is now being honed in conjunction with the Department of Trade and Industry and the British Wind Energy Association.
At the end of July, tests will be run in Wales on a Watchman radar operated by the Royal Air Force. The radar has recorded the interference from several nearby wind farms; filtering software will be installed before Cessna aircraft and RAF helicopters are flown overhead. Only the aircraft should be visible on screen.
Over the next six to 12 months the software will be tweaked before being packaged in a commercial form. BAE, like rival Qinetiq, is also looking at other ways of masking wind farms such as with the use of stealth technology borrowed from fighter bombers.
The efforts could prove a valuable contribution to Britain's efforts to reduce carbon dioxide emissions through the greater use of wind farms.
Under the terms of the Kyoto protocol, the UK government is committed to generating 10 percent of its energy needs from renewable sources by 2010. Wind farms are seen as one of the main ways this target can be met.
To see more of The Business, or to subscribe to the newspaper, go to http://www.thebusinessonline.com.
Source: Knight Ridder/Tribune Business News
