Wind turbines attached to houses generate on average one-tenth of the electricity they would in optimal conditions, research has found.

A two-year study of 133 sites by the British Electrotechnical & Allied Manufacturers Association will encourage supporters of large-scale wind farms in more productive locations and comes a week after a government u-turn over the merits of microgeneration.

Ivan Ball, director of sustainability consultancy Bluesky, said: “This shows that renewables built off site have got to be the way forward.”