Wind turbines 'less efficient than claimed'

Wind turbines are 25 per cent less effective than the renewable energy industry claims, according to research.

The John Muir Trust (JMT), one of Scotland's leading conservation bodies, has challenged the common assertion that wind farms run at an average of 30 per cent capacity over a year.

A study carried out for the Trust into the energy generated by dozens of wind farms, the majority of which are in Scotland, between November 2009 and last month, found they actually ran at 22 per cent of capacity.

Campaigners insist the figures, drawn from data provided by the National Grid, challenge the role of wind farms as an efficient source of renewable energy.

They said hundreds of wind farms had secured planning permission across Scotland based on inaccurate assumptions of their output.

"This analysis shows that over the course of a year, the average load factor fell well short of what the industry claims, yet the 30 per cent figure is peddled at every public inquiry into a proposed wind farm," said Helen McDade, head of policy at the JMT. "This data is needed to counter that hype."
The Telegraph UK