Because blades are constructed from complex materials, they are more difficult and expensive to recycle than other parts of a turbine.
Now an official report into the decommissioning of turbines has warned that rotors could be destined for landfill when they are no longer useful.
The report, for Aberdeenshire Council’s Garioch area planning committee, which met in Inverurie yesterday, also highlights that there is no UK or European legislation that relates specifically to disposal or recycling of redundant turbines.
The document, written by council planning officer Paul Duthie, refers to a Scottish Natural Heritage (SNH) report published in the summer and the Scottish Government’s web-based renewables advice for onshore wind turbines.
It warns that the number of turbines approved, their limited lifespan and increasing opportunities to replace older models with more efficient types, could lead to a rise in the number needing to be decommissioned.
Opponents of wind farms say the revelation is further proof turbines should not be built.
“We have said all along that this industry isn’t environmentally friendly,” said Derek Ross, a campaigner against the proposed Brown Muir wind farm near Elgin, in Moray. He said wind farm projects failed to be “green”, highlighting reliance on using materials from overseas, extraction of peat from the ground, the potential burial of rotors and the visual impact.
Another campaigner from Moray, George Herraghty, of Lhanbryde, said: “A total of 150 tonnes of coal are burned during the manufacture of turbine parts – 250 if it’s offshore.”
Mr Herraghty added: “Most Scottish politicians seemed to have been bamboozled by the propaganda [from] the wind farm industry. These companies look at our countryside and just see empty space. However, places such as the Highlands are our most valuable asset, as well as being very delicate ecosystems.”
There are currently very limited options for recycling rotor blades, which are generally made from fibre-reinforced polymer composites. Mechanical shredding and thermal processing techniques are costly, leaving landfill as the most cost-effective solution.
A spokesman for Danish firm Vestas, the world’s largest manufacturer of wind turbines, said there are solutions for recycling of resin composite materials, but these are generally still at an experimental stage.
Scottish Renewables, the industry body for the renewable energy sector, worked with SNH to develop guidance for decommissioning onshore wind farms.
Senior policy manager Joss Blamire said: “Crucially, this guidance comes years ahead of the time when the majority of wind farms will be restored or decommissioned. This early approach allows the industry to ensure the necessary measures are in place to manage responsible decommissioning of sites.”