The Renewable Energy Foundation (REF) claimed in a recent report that the economic life of onshore wind turbines is 10-15 years, not the 20- 25 generally accepted by the wind industry. It also said that by the time a turbine is ten years old, its contribution to meeting electricity demand has declined by a third.
The issue is significant since the number of years over which a turbine generates electricity affects financing of wind farms, and therefore the cost of energy.
However, economics and technology consultant David Milborrow analysed the data for research unit Windpower Intelligence and found that the performance of onshore wind farms falls off by only around 0.7 percentage points over 20 years, not four percentage points over 15 years as claimed by REF.REF also alleged that performance of offshore turbines declined from around 40% to 10% over ten years. However, Milborrow found that two of the oldest offshore wind turbines actually increased in performance. The third decreased, but only by 1.5 percentage points.