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Wind power's big blades can mask radar; Researchers on a quest to solve problem

The blades' rotation — at speeds as fast as 200 mph — can prevent radar signals from reaching targets and can create radar echoes. The reflected signals — called "clutter" — produce shadows that can hide an object such as a plane. Although no major incidents have been reported so far, leaders on both sides of the issue are looking for ways to mitigate the turbines' radar effects.

Wind turbines blossom across the country, holding the promise of reduced reliance on fossil fuels while having a benign environmental impact.

But turbines also can "erase" aircraft on civilian and military radar, and the whirling blades can mislead meteorologists into thinking a wind farm is a thunderstorm.

The blades' rotation — at speeds as fast as 200 mph — can prevent radar signals from reaching targets and can create radar echoes. The reflected signals — called "clutter" — produce shadows that can hide an object such as a plane.

Although no major incidents have been reported so far, leaders on both sides of the issue are looking for ways to mitigate the turbines' radar effects.

The problems "are serious but solvable," Dorothy Robyn, a deputy Defense Department undersecretary, testified at a recent congressional hearing.

Others participating in efforts to find common ground include wind-energy and Federal Aviation Administration representatives.

"The same solution will not work everywhere," said Tom Vinson, spokesman for the American Wind Energy Association. The type of terrain, how the turbines are aligned and the type of radar in use all play a role, he said.

Solutions include upgrading radar, getting... more [truncated due to possible copyright]  

Wind turbines blossom across the country, holding the promise of reduced reliance on fossil fuels while having a benign environmental impact.

But turbines also can "erase" aircraft on civilian and military radar, and the whirling blades can mislead meteorologists into thinking a wind farm is a thunderstorm.

The blades' rotation — at speeds as fast as 200 mph — can prevent radar signals from reaching targets and can create radar echoes. The reflected signals — called "clutter" — produce shadows that can hide an object such as a plane.

Although no major incidents have been reported so far, leaders on both sides of the issue are looking for ways to mitigate the turbines' radar effects.

The problems "are serious but solvable," Dorothy Robyn, a deputy Defense Department undersecretary, testified at a recent congressional hearing.

Others participating in efforts to find common ground include wind-energy and Federal Aviation Administration representatives.

"The same solution will not work everywhere," said Tom Vinson, spokesman for the American Wind Energy Association. The type of terrain, how the turbines are aligned and the type of radar in use all play a role, he said.

Solutions include upgrading radar, getting radar operators more training and altering the layout of a wind farm.

Companies such as Vestas, which has facilities in Windsor, Brighton and Pueblo, are researching how to make "stealth" blades for turbines. The work focuses on how to coat the blades or use materials that make the blades invisible to radar.

The FAA has jurisdiction over any structure more than 200 feet high. Plans for turbines, which range from 200 feet to 400 feet high, must be submitted to the agency, which reviews them for potential hazards.

Joining in the reviews are the Colorado Springs-based North American Aerospace Defense Command, charged with aerospace warning and aerospace control for North America; the Department of Homeland Security; and the National Oceanic and Atmospheric Administration.

The concerns are not new but have grown as wind farms have proliferated.

"In recent years, as the need for alternative energy has become a major focus of government and industry, the volume of proposed wind turbines submitted to the FAA for review has increased dramatically," said Nancy Kalinow ski, the FAA's vice president of system operations services.

The FAA handled 3,030 wind-turbine cases in 2004; in 2009, that was up to 25,618. As of June 30 this year, there have been 18,685 cases.

Vinson said wind-turbine concerns first became an issue in 2006, "and there have been periodic flareups." Conflicts have arisen in Oregon; Illinois, Texas and California, but not Colorado. No crashes or incidents have been reported.


Source: http://www.denverpost.com/c...

JUL 17 2010
https://www.windaction.org/posts/27300-wind-power-s-big-blades-can-mask-radar-researchers-on-a-quest-to-solve-problem
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