Wind turbines

Economics are pushing the size of wind turbines upwards. Having fewer, larger turbines reduces the number of expensive towers, foundations, erection operations and power collection cables that are needed. This is more crucial in the offshore sector, where the largest turbines can therefore be expected. Today we see turbines of 3 - 3.5MW with rotors of 80 - 90m diameter coming into the market, while recently a 5MW unit from RE Power, with a 126m rotor, started operating experimentally in Germany. Talk is of turbines at least double this power eventually. But is such talk realistic and are there factors likely to limit wind turbine growth? George Marsh reports.