Laserfiche WebLink
<br />NON-IsSUES/"RED HERRINGS" <br /> <br />The following are common misconceptions about small wind: <br /> <br />i. Shadow "FlIcker" v. i:lectrical Signal Interference <br />ii. Fences! Attractive Nuisance vi. Lightning Strikes <br />iii. Birds vii. Stray Voltage <br />iv. "Ieing" <br /> <br />i. Shadow "Flicker": <br /> <br />Under very specific circumstances, low <br />sunlight passing through the moving <br />rotor of a turbine can cast visible <br />shadows on the ground or on structures. <br />This issue pertains almost exclusively <br />(and similarly rarely) to large, utility- <br />scale turbines because of their slower- <br />moving blades. Shadows also depend <br />on the time of day, day of year, and <br />latitude of the site's 10cation.11 <br /> <br />Small turbines are shorter, have <br />narrower blade profiles, and spin <br />much faster than utility-scale turbines <br /> <br />so that any shadows become essentially <br />invisible at operating speeds. Turbines <br />of all sizes are designed to start <br />spinning only after a minimum wind <br />speed has been attained, so chances <br />are very slim that a small turbine will <br />spin slowly enough to make shadow <br />flicker a concern. <br /> <br /> <br />Furthermore, normal setback distances <br />dictated by property lines or sound <br />requirements mitigates, if not entirely <br />eliminates, this potential nuisance, <br />especially at U.s. latitudes. <br /> <br />Northern Power <br />lOOkW turbine <br />in Golden, Colorado <br /> <br /> <br />11 The possibility of shadow flicker affecting a given <br />location can be calculated very precisely. See <br />http://www. wi ndpower. org/ en/tou r/ env I shadow/ <br />shadowc.htm for a shadow flicker calculator. <br />