Lindsey Chew<\/p>\n
Professor Grace<\/p>\n
EK132 Intro to Wind Energy<\/p>\n
11\/28\/12<\/p>\n
Wind energy is one of the fastest growing electric power sources in the United States. Massachusetts alone produces over 90MW of land-based wind power capacity and plans to install wind turbines to produce 2000MW of energy by 2020. 1000MW of wind power can offset 2.6 million tons of CO2 (5). Wind energy is also now competitively priced, offering an advantage over coal solutions because of its clean-burning nature. Despite the obvious environmental benefits of using wind turbines to produce energy, the potentially dangerous health effects of placing these turbines within public view and hearing have raised social unrest and concern. One negative health effect of wind turbines is ice throw; however, the risks of ice throw are preventable. I believe that the government should continue to support wind turbine construction despite ice throw possibilities.<\/p>\n
Ice throw is a possible risk that poses a threat to surrounding residents of a wind turbine field. In areas of cold climate, ice can accumulate on turbine blades and break off the machine with drops in temperature, unexpectedly. In the small town of Whittlesey, England December 2008, \u201clumps of three or four feet long flew through the air,\u201d into a carpet showroom and parking lot due to wind turbine ice throw. Residents described ice shards as \u201cjavelins\u201d (2). The wind industry, however, rebuts with the fact that all tall structures such as skyscrapers, trees, utility poles, roofs and cell phone towers will develop ice that can fall and injure observers down below (7). \u00a0The case of Whittlesey wind turbines is abnormal and could have been prevented with proper safety measures.<\/p>\n
The effects and amounts of ice throw produced by a wind turbine are predictable, depending on its location, height, and blade length. In most cases, ice falls within a radius of the tower equal to the tower height, and rarely exceeds total height (tower height plus blade length) (4). Also, wind power generation facilities in southern regions have warm climates that preclude the issue of ice (3). The energy company GE lists specific guidelines that must be implemented in order to reduce dangers of ice throw, such as using the formula (1.5 * (hub height + rotor diameter)) to calculate a safe distance, place warning signs near wind turbine range, remotely switch off turbine site personnel detect ice accumulation, and restricting direct physical access to turbines by workers and the public (9).<\/p>\n
In Wisconsin, precautions have been implemented for determining the risk of turbine location. An estimate should be made of the time (days per year) in which icing conditions occur at the turbine site to determine the risk of construction in that area. In Wisconsin, they categorized \u201cheavy icing\u201d as more than 5 days, less than 25 days, \u201cmoderate icing\u201d as more than 1 day, less than 5 days, \u201clight icing\u201d as less than 1 day per year, and \u201cno icing\u201d as warm climate areas where no icing would occur (7). Sites for wind turbines can then be chosen from the \u201clight\u201d to \u201cno icing\u201d categories.<\/p>\n
The town of Arkwright in New York has taken precautions against ice-shedding such as turbine-shut-down, in which ice that accumulates on rotor blades will cause a weight imbalance, automatically turning off the turbine motors. Once the ice melts, the turbine can only be turned back on by a worker (10). Turbine shut-down mechanisms can prevent issues of ice throw.<\/p>\n
Heating the blade\u2019s surface is another option. Active anti-icing systems include electrical resistance heating (heating a membrane on the blade\u2019s surface) and indirect heating of the surface (using a radiator from the inside of the blade). In 1996, Yukon Energy painted their blades with a Teflon-like material called StaClean, a highly slick substance that ice tended to fall off of. This is an example of a passive anti-icing system (1).<\/p>\n
<\/strong><\/p>\n <\/strong>Remote monitoring and operating is now required in the wind energy industry; all commercial machines have ultrasonic vibration sensors which automatically shut down turbines when ice is detected at a pre-set level (detecting 40-70kHz frequencies). Devices having heating elements that switch on at shut-down level are also desirable. Icing rate is important to take into account to note the efficiency of location and long-term usage of the turbine (8).<\/p>\n Successful wind turbine sites in Wisconsin and New York, as well as anti-icing mechanisms have worked in the past, an indication that ice throw issues can be mitigated. The government should allow for the construction of wind turbines, as long as they maintain safety measures and precautions such as guidelines as to calculate a safe distance from residential areas, determining the risk of ice accumulation at the site region, shut-down mechanisms, remote monitoring and operating systems and active\/passive anti-icing systems. The benefits of implementing wind energy for the sake of the environment and clean energy usage are worth taking the extra precautions.<\/p>\n <\/p>\n Works Cited<\/p>\n <\/p>\n 1. Carriveau, R; Dalili, N; Edrisy, A. \u201cA Review of Surface Engineering Issues Critical to Wind Turbine Performance.\u201d Elsevier. Vol. 13 Issue 2, February 2009, pages 428-438.<\/p>\n http:\/\/www.sciencedirect.com.ezproxy.bu.edu\/science\/article\/pii\/S1364032107001554<\/p>\n 2. Galbraith, Kate. \u201cIce-Tossing Turbines: Myth or Hazard?\u201d The New York Times. December 9, 2008. http:\/\/green.blogs.nytimes.com\/2008\/12\/09\/ice-tossing-turbines-myth-or-hazard\/<\/a>.<\/p>\n 3. \u201cIce Throw.\u201d Blue Highlands Citizens Coalition. 2004. http:\/\/www.bhcc.ca\/ice_throw.htm<\/a>.<\/p>\n 4. Independent Expert Panel of Massachusetts Government. \u201cWind Turbine Health Impact Study\u201d MassGov. January 2012.<\/p>\n http:\/\/www.mass.gov\/dep\/energy\/wind\/turbine_impact_study.pdf<\/a><\/p>\n 5. \u201cLand-based Wind Energy: A Guide to Understanding the Issues and Making Informed Decisions.\u201d CLF Ventures. <\/span>June 2011.<\/p>\n http:\/\/www.clfventures.org\/wp-content\/uploads\/Wind_Guide.pdf<\/a><\/p>\n 6. \u201cNoise and Health Effects of Large Wind Turbines.\u201d National Wind Watch, Inc. Oct. 25, 2006. http:\/\/www.wind-watch.org\/ww-noise-health.php<\/a>.<\/p>\n 7. Sangrillo, Mike. \u201cHome-Sized Wind Turbines and Flying Ice.\u201d Windletter. Volume 22, Issue No. 6, June 2003.<\/p>\n http:\/\/www.renewwisconsin.org\/wind\/Toolbox-Fact%20Sheets\/Ice%20shedding.pdf<\/a><\/p>\n 8. Seifert, Henry. \u201cAssessment of Safety Risks from Wind Turbine Icing.\u201d Dutch Wind Energy Institute.<\/span> April 2, 1998.<\/p>\n