The evolution of the conventional wind turbine is a great illustration of where we want to go: high in the sky.

Why?
At higher altitudes (200 meter and above) the average wind speeds are higher and more consistent. The power that can be extracted from the wind grows cubically with the wind speed, making higher altitudes a desirable choice as location for wind energy generators. Due to both higher wind speeds and its consistency, capacity factors can be up to 50% higher than at conventional wind turbine heights.

Publications related to the resource :

C. Archer and K. Caldeira. Global Assessment of High-Altitude Wind Power. Energies, 2, 307-319, 2009.

C. Archer and K. Caldeira. Atlas of High-Altitude Wind Power. Dept. of Global Ecology, Carnegie Institute for Science, Stanford, 2008.