Special thanks to Sullivan & Worcester's Ari Hoffman, environmental intern, for assisting in the preparation of this post.
On June 28 and 29 in Ottawa, the Canadian Wind Energy Association (“CanWEA”) in collaboration with the American Wind Energy Association (“AWEA”) hosted the International Wind and Radar Forum. The Forum was designed to “further the relationship between key regulatory and industry players, while promoting an international dialogue about responsible, effective tools designed to identify and address any potential conflicts between wind energy and radar.”
Tension between ensuring aviation security and expanding wind energy has arisen due to a wind turbine’s potential to interfere with the radio frequency waves emitted by radar systems. Wind turbines can defeat radar, especially when grouped into large wind farms, either by creating unwanted reflections or by blocking signals which can result in clutter on radar maps. Radar clutter prevents aircraft and surface air traffic controllers from determining the location, range, altitude, direction and speed of nearby objects, posing a safety threat.
Due to concern over aviation security, the British Wind Energy Association (“BWEA”) estimates that there is 4.7 gigawatts of wind energy on hold in Britain and AWEA estimates that in the United States over 9.0 gigawatts of wind energy are on hold. These statistics are worrisome to the United States Department of Energy, which relies heavily on the use of wind energy to help reach the nation’s renewable energy targets.
A myriad of solutions to this problem have emerged. Earlier this year, the United States Department of Homeland Security awarded a $22 million contract to Raytheon, a leader in this field, to study how proposed wind farms would interact with existing radar systems. CASSADIAN, the defense and security division of EADS, developed a solution based on modifications to the radar antenna as well as signal processing. Further, SCANTA 4002 Radar, a system developed by Terma, is designed to separate smaller air objects from larger surface objects, such as wind turbines. This radar can be independently installed and integrated with existing radar installations.
While some solutions try to change radar systems, Vestas is working to change wind turbine blades into radar-friendly stealth blades. Vestas believes the solution lies in coating blades with similar material used to produce stealth planes which are invisible to radar. Vestas announced on June 29, 2011 that the use of “stealthy” blades reduce radar clutter by around 99% or 20 decibels (The Guardian UK).
As wind energy expands, radar and blade technologies to avoid disturbances will become even more vital, especially to smaller aircraft that may fly along less traveled routes where large wind turbine farm development is more likely. As this issue progresses, please check back to this blog for future posts.