The economic life of onshore wind turbines could be up to ten years less than that projected by the wind industry itself, the Renewable Energy Foundation has warned.

The charity published a study – The Performance of Wind Farms in the United Kingdom – which found that the economic life of onshore wind turbines was between 10-15 years, not the 20-25 years projected by the wind industry and used for government projections.

Led by Gordon Hughes from the University of Edinburgh, the study looked at years of performance data from wind farms in both the UK and Denmark.

Taking into consideration variations in wind speed and site characteristics, the study found that the average load factor – average real output – of wind farms declined substantially as they got older, probably due to wear and tear.

In addition, the study found once it reached 10 years old, the contribution of an average UK wind farm to meeting electricity demand declined by a third.

The study suggested that due to this decline in performance, it was rarely economic to operate wind farms for more than 12-15 years, after which they must be replaced with new machines.

The study also found that performance of new UK onshore wind farms had declined significantly between 2000 and 2011, especially in Scotland, with progressively worse sites being deployed. While, larger wind farms were found to have a worse performance than smaller ones.

“Meeting the UK government’s targets for wind generation will require a much higher level of wind capacity and capital investment than current projections imply,” said Prof Hughes.

Gemma Mackenzie on G+