From an E mail sent to me.
According to Caithness Windfarm Information Forum, as more wind farms are built, more failures occur. The forum notes that of the average 104 turbine incidents each year, by far the biggest number are related to blade failure resulting in either whole blades or pieces of blade being thrown from the turbine. A total of 208 separate blade failure incidents have been reported up to June 2011.
Fraser McLachlan, CEO at G Cube comments: “There have been a number of significant [blade] failures this year. They are costing the insurance industry millions of euros.”
Indeed, the rotor represents between 15-20% of the total cost of a turbine. And large blades which can be up to 70m long cost anything between US$30,000 and US$100,000 each. In addition replacing a single blade is not an isolated cost- work needs to be done to ensure that the two remaining blades are properly balanced.
An average of 104 per year. so they’re not only inefficient, but downright dangerous. An example:
Blade failure 06/09/2011 Lister Hospital,
"Six-foot blade flies off new Lister turbine". A six-foot blade flew off after only a week's
operation, and landed on a car, damaging its roof. The turbine is on the roof of a brand new
Hospital car park.
And that’s only a small one. Just imagine what a 70m one would do.
Worth a look here if you would like to see a table of accidents to turbines and the resulting outcomes.