The lifespan of windfarms is significantly shorter than the billed 20 to 25 years, according to a new study by an energy charity.
Just before Christmas, the Renewable Energy Foundation published The Performance of Wind Farms in the United Kingdom and Denmark, showing that the economic life of onshore wind turbines is between 10 and 15 years, not the 20 to 25 years projected by the wind industry itself, and used for government projections.
And it also raises issues surrounding the subsidies currently paid out to the industry.
Dr John Constable, director of Renewable Energy Foundation, said: “This study confirms suspicions that decades of generous subsidies to the wind industry have failed to encourage the innovation needed to make the sector competitive.
“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.”
The work has been conducted by one of the UK’s leading energy and environmental economists, Professor Gordon Hughes, of the University of Edinburgh, and anonymously peer-reviewed.
It applies rigorous statistical analysis to years of actual windfarm performance data from sites in both the UK and Denmark.
The results show that, after allowing for variations in wind speed and site characteristics, the average load factor of windfarms declines substantially as they get older, probably due to wear and tear.
By 10 years of age the contribution of an average UK wind farm to meeting electricity demand has declined by a third.
This decline in performance means that it is rarely economic to operate windfarms for more than 12 to 15 years.
The study points out that policymakers expecting windfarms built before 2010 to be contributing towards CO2 targets in 2020 or later must allow for the likelihood that the total investment required to meet these targets will be much larger than previous forecasts have suggested.
As a consequence, the lifetime cost per unit (MWh) of electricity generated by wind power will be considerably higher than official estimates.
However, the study comes at a time when official figures from the Department of Energy and Climate Change show that nearly 12 per cent of the country’s electricity came from renewable sources in the third quarter of 2012, equalling the record set in quarter four of 2011 of 11.7 per cent.
It was the third time that renewables have exceeded 10 per cent of UK electricity in a three-month period.