Energy available in the wind

Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind speed doubles. Wind turbines for grid electricity therefore need to be especially efficient at greater wind speeds.

Unfortunately, the general availability and reliability of wind speed data is extremely poor in many regions of the world. Large areas of the world appear to have mean annual wind speeds below 3m/s, and are unsuitable for wind power systems, and almost equally large areas have wind speeds in the intermediate range (3-4.5m/s) where wind power may or may not be an attractive option. In addition, significant land areas have mean annual wind speeds exceeding 4.5m/s where wind power would most certainly be economically competitive.