Potential safety concerns related to wind turbines include physical danger resulting from blade failure, tower collapse or turbine fires. These types of incidents are extremely rare, and modern turbine design and quality control have greatly reduced their risk of occurrence.
The California Wind Energy Collaborative conservatively estimates the risk of blade failure is 1 in 1,000 (0.1%) turbines per year (California Wind Collaborative 2006). Tower collapse is even rarer than blade failure and the risk of human injury is small, since the impacts from tower collapse are confined within a relatively short distance from the turbine (California Wind Collaborative 2006).
Public safety setbacks are designed to protect people, property and common services from the types of events described above. Honolulu City and County code requires wind turbines to be set back from all property lines by a distance equivalent to the height of the turbine (including the height of the blade). The setbacks at the Na Pua Makani wind farm will far exceed these minimum setback requirements by several orders of magnitude.