Here is a reprint of an email about ice throw at Green Mountain Power's Searsburg wind energy facility in Searsburg Vermont. The email was written by John Zimmerman to an American Wind Energy Association listserv in 2000. Mr. Zimmerman managed the development of the Searsburg facility

The official OR-OSHA report on the August 2007 turbine collapse at the Klondike III wind facility in Oregon can be accessed below. Siemens Power Generation, Inc. was fined $10,500 and cited in part for failing to properly train personnel.

These internal FPL employee meeting communications were anonymously released to the St. Lucie County Attorney Dan McIntyre. The documents show clear knowledge that FPL was aware of potential risks to their nuclear power plant if the company proceeded with a wind energy facility nearby.

This short GE Energy document explains the risk in the event of extreme wind conditions including hurricane or tornado and any mitigation. Note, the document acknowledges the risk of blade throws and tower collapse.

This interview with retired EMS pilot Ray Slavik was submitted to the Calumet County Ad Hoc Committee researching proposed ordinances governing the placement of wind turbines in the county. The interview provides important insight into controling an aircraft in the vicinity of utility-scale turbines.

Some elements to consider in policy, planning, and public relations

This chapter provides guidelines for the marking and lighting of wind turbine farms. For the purposes of this advisory circular, wind turbine farms are defined as a wind turbine development that contains more than three (3) turbines of heights over 200 feet above ground level. The recommended marking and lighting of these structures is intended to provide day and night conspicuity and to assist pilots in identifying and avoiding these obstacles.

The California Wind Energy Collaborative was tasked to look at barriers to new wind energy development in the state. Planning commissions in the state have developed setback standards to reduce the risk of damage or injury from fragments resulting from wind turbine rotor failures. These standards are usually based on overall turbine height. With the trend toward larger capacity, taller towers and longer blades, modern wind turbines can be "squeezed out" of parcels thus reducing the economic viability of new wind developments.

Current setback standards and their development are reviewed. The rotor failure probability is discussed and public domain statistics are reviewed. The available documentation shows rotor failure probability in the 1-in-1000 per turbine per year range. The analysis of the rotor fragment throw event is discussed in simplified terms. The range of the throw is highly dependent on the release velocity, which is a function of the turbine tip speed. The tip speed of wind turbines does not tend to increase with turbine size, thus offering possible relief to setback standards. Six analyses of rotor fragment risks were reviewed. The analyses do not particularly provide guidance for setbacks. Recommendations are made to use models from previous analyses for developing setbacks with an acceptable hazard probability.