A surge in demand for renewable energy has led to a large order backlog for the world's biggest wind turbine-maker, Vestas Wind Systems.The Danish firm said it had 7.2bn euros ($10.6bn; £5.7bn) worth of orders still to fulfil at the end of June, up 67% on a year earlier. Vestas made 98m euros profit after tax in the first six months of 2008, 44% higher than the same period in 2007.The firm is expecting further growth as the use of wind power grows globally. chance," Dengate said.
