The following is from an article published in WindStats Newsletter Vol. 19, No. 4. The complete article is available from WindStats at:

“It comes as no surprise that much of today’s wind power research focuses on increasing blade lengths. The weight of a rotor can take up as much as 77% of the total weight of a system, says John Locke, a researcher at Wichita State University’s National Institute for Aviation Research.

Yet, according to Dr. Paul Veers of Sandia National Laboratories, blades account for just 10% of a turbine’s cost: If you double the [cost] of your blades, that would only increase [system] cost by 10%, says Veers. But if you increase your swept area by just 20%, you win, as that represents a substantial boost in power output.”