New research has suggested the economic lifespan of windfarm turbines is up to 10 years shorter than previously thought.
A study by an energy and environment economist on behalf of the Renewable Energy Foundation revealed that machinery was only viable for 10-15 years instead of the 20-25 years projected by the wind industry and governments.
Edinburgh University professor Gordon Hughes, who based his research on windfarm data from the UK and Denmark, said the contribution of an average turbine development to electricity demand fell by a third within 10 years due to wear and tear.
The study claims decline in performance means it is rarely economic to operate sites for more than 12-15 years and turbines would have to be replaced which would have “profound consequences” for investors and governments.
Prof Hughes claimed “larger windfarms have a systematically worse performance than smaller ones”. Highland anti-windfarm campaigner Lyndsey Ward, of Kiltarlity, Inverness, said it made “sobering” reading and reinforced the need to stop future developments until “indisputable facts” were laid out by independent experts.
Tory MSP Murdo Fraser, convener of the Scottish Parliament’s energy committee, said: “This is another damning verdict on wind energy and if the SNP isn’t going to listen to communities or councils, it should listen to experts.”
Prof Hughes said some investors were aware of the decline in turbine performance but continued to invest, which suggested subsidies were so generous they “compensated for the fall in output”.
John Constable, director of the London-based Renewable Energy Foundation, added: “Bluntly, wind turbines onshore and offshore still cost too much and wear out far too quickly to offer the developing world a realistic alternative to coal.”
But Jenny Hogan, of industry body Scottish Renewables, said: “Our oldest commercial windfarms in Scotland are around 16 years old and none of them have been decommissioned or repowered.
“Everyone who drives a car understands parts will need to be replaced and there will also come a time when you want to trade in for a better, more suitable model – it’s not much different for windfarm operators.”
The Scottish Government has a target to generate 100% of electricity through renewables by 2020. A spokeswoman said: “Wind power is already making a meaningful contribution to Scotland’s power supplies, with onshore wind meeting around 18% of forecast Scottish energy demand for 2011.
“We have a responsibility to make sure our nation seizes this opportunity.”