Wind Energy Development

Abstract

Wind energy technology has been characterised by a very rapid growth in capacity which is now approaching 600 GW, worldwide. Machine sizes have grown from 10 to 20 m diameter in the early 1980s, and the largest machines are now over 160 m diameter, with larger machines under development. The rated output of the largest machines is now around 10 MW. During the last 40 years, numerous design configurations have been used, but the industry has now settled on three-blade rotors that run upwind of the tower. There is an increasing focus on direct-drive wind turbines, but there are still numerous manufacturers offering geared machines. Although there has been some interest in vertical-axis wind turbines, the concept has not been taken up at megawatt-scale, although there is still some work in progress. As machines have grown in size, they have benefited from the higher wind speeds found at greater heights, and so energy productivity has increased.