As concerns over climate change, geopolitical disputes, and increasing energy demands rise, the United States has recognized wind energy as an integral part of our energy mix in the future. However, agencies such as the U.S. Department of Defense (DoD), U.S. Department of Energy (DoE), Federal Aviation Administration (FAA), and the National Weather Service (NWS) have reported that the towers and rotating turbine blades degrade radar quality due to adverse shadowing and clutter effects in the line-of-sight of radar applications [1,2]. These effects have the potential to threaten national security by impacting the country’s military air defense operations, decrease air safety by reducing Air Traffic Controllers’ ability to monitor the U.S. airspace, and decrease the accuracy of weather prediction [1]. Consequently, the U.S. government has implemented broad restrictions on the development of new wind projects that may interfere with civilian or military radar although mitigation techniques have been proposed that may allow the two to coexist [1].
On February 14, 2009, the FAA spoke out against the 420 MW Cape Wind Project, which includes plans to install 130 turbines in the Nantucket Sound. The site, off the shores of Massachusetts, was chosen because of its characteristically persistent and intense winds, but has been accused of interfering with 3 major FAA radar systems [4]. The FAA claims that the turbines will add extraneous clutter that may reduce its ability to monitor the sky since rotating turbines resemble aircraft on radar. Since this would be the United State’s first off-shore wind project, the FAA’s block forecasts a new era of controversy over off-shore wind projects. The Cape wind project has already weathered years of heavy criticism from the public because of environmental concerns and those who claim it will be an “eyesore” on the horizon [4].
In the near-future governing bodies such as the DoD, DoE, FAA, and NWS, must decide whether they are willing to put in substantial resources into upgrading already very expensive radar systems to filter out wind turbine clutter, or if they will redesign wind turbines to be less obtrusive to radar clutter, which may substantially increase the cost of production due to the need for more expensive radar absorbing materials [2]. The alternative would be to simply block the financing of off-shore projects in areas that would intercept civilian and military radar. In many senses the Cape Wind Project will set the tone for the off-shore wind industry in the next few months based on how this block by the FAA is handled.
1. Report to the Congressional Defense Committees: The Effect of Windmill Farms on Military Readiness, U.S. DoD, September 2006.
2. Rashid, L.S.; Brown, A.K., RCS and radar propagation near offshore wind farms, 2007 IEEE Antennas and Propagation Society International Symposium (9-15 June 2007) pg. 4605 – 4608.
3. “FAA: Controversial Cape Wind project could be radar hazard,” The Boston Herald, February 14, 2009. http://www.bostonherald.com/business/general/view.bg?articleid=1152140&srvc=business&position=3
4. Grad, P. “Offshore USA: The Cape Wind offshore wind farm: a first for the USA?”, Refocus, Volume 6, Issue 5, September-October 2005, Pages 34-36. doi:10.1016/S1471-0846(05)70456-X .
