Agenda - Planning Commission - 08/06/2009

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v. Electrical Signal Interference: Small wind turbines are commonly used to power communications equipment. They will not cause signal. interference. Small wind turbine blades are made from materials that are "invisible" to radio frequency transmissions and cannot cause interference problems. In fact, small wind turbines are used by the U.s. Navy to power military communications equipment.15 In the past; wind turbine blades were sometimes made of metal which did create unwanted radio <?r television interference, but the industry has long vi. Lightning Strikes: Wind turbines do not attract lightning, so pose no threat to neighboring properties. Bergey WindPower lkW turbine on telecommunications station in Bristol Bay, Alaska Lightning is essentially the release of pent-up static electricity that moves from a turbulent atmosphere to the ground. Small wind turbines are "grounded," meaning that any static electricity on the tower or generator is dispersed into the ground, preventing a build-up that could invite lightning strikes. As a result, even though small wind turbine towers are made of metal (a conductor of 'electricity), by virtue of their grounding they are less susceptible to lightning strikes than trees, which cannot shed built-up static electricity. To a lightning bolt, a turbine istherefore Proven Energ'y 6kW turbine powering telecommunications equipment since abandoned the use of metal blades. Any structure under 200 feet high - that is to say, any small wind turbine - is also too short to interfere with civilian or military radar. Radar usually does riot even scan for objects this close to the ground because common land features at this height, like treesr would normally cause distorted, cluttered, or misleading . radar images. no more "appealing" than the ground itself. However, lightning strikes are still possible, which is why small wind turbines incorporate back-up technologies like surge and lightning arrestors (also known as silicon oxide varistors) and metal oxide varistors, which are also used to protect home computers from electrical surges. Lightning strikes are never completely preventable, but these industry- standard measures offer the best protection available to the owner of the wind system. Good practice in the wind industry includes grounding of all towers and guy wires, which Significantly reduces the chance of a lightning strike. 15 SagrillD, Mick. "TelecDmmunication Interference from Home Wind Systems." AWEA Windletter, Volume ZZ, Issue 4, April Z003.