BT has started trials of a new wind-powered generator at one of its telephone exchanges in Lanreath, Cornwall. If successful the experiment is likely to increase interest in wind energy among companies, as power prices come under pressure from the rising cost of oil and gas. But the economics of wind remain in dispute.

BT has been one of the more enthusiastic supporters of renewable energy and last year became the world's biggest company to commit to taking all its electricity from environmentally sound sources. But most companies are yet to be convinced as to whether wind energy is cheaper than conventional forms of energy with recent studies sending conflicting messages.