WASHINGTON, D.C — Pilots and aircraft owners might find that efforts to go green will cost them a lot of green.
Planning over where, when and how to build wind turbine farms is little known among many general aviation users, but can have a major direct effect.
Federal agencies are wrestling over development of wind turbine power to meet the demand for electricity, government mandates for reducing power plant emissions, and a decline in the use of oil products.
For aviation — private, air carrier and military — the placements selected for these wind turbine farms mean interference with radar, both for air traffic control and weather reporting. The number of structures in a farm, their height, size of the blades, and speed of rotation, are some of the issues that cause concerns.
President Bush has said that wind energy could acccount for 20% of the nation’s electrical power. That would mean a lot of wind turbines, a potential that pleases the American Wind Energy Association but one that raises red flags for many others.
Wind turbines are composed of highly reflective materials, such as fiberglass, plastics and epoxy paints. Many are more than 400 feet tall. From the base to the tip of a blade at its highest is about 112 feet taller than the Statue of Liberty. Blades, which spin at up to 168 miles per hour, reflect radio waves.
What does all of this mean? According to scientific studies, it means partial or complete loss of signal strength on radar, and clutter that can mask the true location of an aircraft and produce a large radar cross section — that is, the distance around the object.
In some locations hundreds of these wind turbines are planned. Although this would be particularly troublesome on aircraft approaches, interference and loss of aircraft primary detection have been found as high as 6,000 feet above turbine farms. Weather radars also have trouble. It is a particularly troublesome effect when trying to give accurate conditions at low levels for approaches.
Many areas in the country are already facing problems. Offshore areas of New Jersey have special restrictions relating to Department of Defense concerns. Nantucket is another place where problems are seen. Many studies have been made and many more are to come as the locations of farms are approved on a case-by-case basis.
England has been wrestling with the issue for a number of years, with the Royal Air Force voicing strong objections to wind turbine farms near any of its airfields. The RAF has conducted detailed surveys and studies on the subject, including a 2005 study which showed that the effects on terminal radar included a reduction in signal strength or complete loss of expected display.
Although the Department of Energy has direct responsibility for wind power issues, many government agencies are involved in the Federal Interagency Wind Siting Collaboration, formed to coordinate among the various government agencies. The military and, of course, the FAA are members. So are the Department of Homeland Security and any group involved in “”regulatory, policy, technology or marketing”" of wind turbine farms.
Ironically, the siting of wind turbine farms near airports could be a major boost for the FAA’s drive for Automatic Dependence Broadcast-Surveillance (ADS-B), which does not need ground radar and might make the farms more acceptable near airports But, if it is required, look for the expense of equipping your aircraft. Will going green cost you green?
Charles Spence is GAN’s Washington, D.C., correspondent.