ThinkGreenResources.com
Wind Energy Potential
Good wind areas, which cover 6% of the contiguous U.S. land area, have the potential to supply more than one and a half times the current electricity consumption of the United States. Estimates of the wind resource are expressed in wind power classes ranging from class 1 to class 7, with each class representing a range of mean wind power density or equivalent mean speed at specified heights above the ground. Areas designated class 4 or greater are suitable with advanced wind turbine technology under development today. Power class 3 areas may be suitable for future technology. Class 2 areas are marginal and class 1 areas are unsuitable for wind energy development.
Because techniques of wind resource assessment have improved greatly in recent years, work began in 2000 to update the U.S. wind atlas. The work will produce regional-scale maps of the wind resource with resolution down to one square kilometer. The new atlas will take advantage of modern techniques for mapping. It will also incorporate new meteorological, geographical, and terrain data. The program's advanced mapping of the wind resource is another important element necessary for expanding wind-generating capacity in the United States.
Source http://www1.eere.energy.gov/windandhydro/wind_potential.html