Below is a response I received from Mike Crawley of AIM Powergen about turbine collapses. My responses to him are in red. I added some qualifying statements in blue to help you understand the background.
Thank you for sending through a copy of the article from Business Week.This article pointed out the increased number of turbine collapses there has been in recent years. We are aware of this article. I will try to include in my postings.
While the risk of turbine tower collapse is real, the probability of this happening is extremely low and needs to be looked at in context. Considering the number of turbines that are installed worldwide and the number of catastrophic failures it is clear that the risk is extremely low. Earlier correspondence from E. Fenelle stated that there has only been one collapse out of the 100,000 turbines installed today. This correspondence is from AIM’s Env. Assessment company Helimax. These risks need to be put into context alongside the risk of failures of other built structures in our environment (ex. power lines, communications towers, silos, etc.) or natural features such as trees. The risks are no greater for wind turbines than these other examples. I am not sure how you equate the risks of a tree falling to that of a 120 m turbine that has a nacelle which weighs alone 67 metric tonnes.
There are, as you demonstrate, examples of component failures, ex. turbine blades, that fail more often. Ihave a contact in Port Burwell who was talking to the maintenance people for those turbines, and they have been finding bolts at the base of the turbine when opening the doors at the base of the turbine. Again, the nature of the event and the risk associated needs to be assessed and compared to risks in our environment already. What elements in our environment have the potential to throw blades with distances of 400 m? Please see site http://www.caithnesswindfarms.co.uk/
What does not appear in any of the examples you raise is a death or serious injury to persons from the general public. O.K. the risk is not real until someone gets hurt or dies? While these failures have the potential to cause property damage, no member of the public has been killed by a wind turbine failure. This is untrue 49 fatalities have been attributed to wind turbines, 14 were public fatalities. The deaths attributed to wind turbines are limited to workers associated with the turbines, either in construction, operations or maintenance. While these are unfortunate, the risks associated with these failures have also to be reviewed in context. The incidents of injury or death are not out of the realm of normal workplace accidents or deaths. Wind farms, as with any industrial workplace, are subject to strict workplace health and safety regulations. The risk of accidents is always there of course, as it is in an automotive plant, a construction site or in a local farm operation. Our industry takes these issues very seriously and strives to ensure a safe work environment for all involved.
Iwill try to include other responses in the future for your perusal. The mindset completely boggles my sense of decency.