According to the U.S. Department of Energy, can provide more power than the entire nation's electricity needs. The plains states (northern Texas up to the Dakotas) have been called the Saudi Arabia of wind. In 2001 (before natural gas got really expensive), wind was already cost-competitive with natural gas power plants in some parts of the country.
In the past 20 years, wind technology has come a long way. The cost has dropped dramatically and continues to drop as conventional power sources become more expensive. Modern wind turbines can produce more and more power (currently, the large ones can produce 1.5 megawatts each and 2-3 megawatt types are currently under testing and development).
North and South Dakota alone have enough wind energy from its highest wind speed sites to supply over half of the electricity needs of the lower 48 states. A group of 12 states in the midsection of the country have enough wind energy potential to produce nearly four times the amount of electricity consumed by the nation in 1990.
According to the American Wind Energy Association:
"Installed wind energy generating capacity now totals 6,374 MW, and is expected to generate about 16.7 billion kWh of electricity in 2004. That is still less 1% of U.S. electricity generation. By contrast, the total amount of electricity that could potentially be generated from wind in the United States has been estimated at 10,777 billion kWh annually—more than twice the electricity generated in the U.S. today."
-Wind Energy: An Untapped Resource
Worldwide, it's been demonstrated the there is enough wind power to power the entire earth's population:
Many have expressed concern about bird kills from wind turbines. Wind turbines kill an average of about two birds per turbine per year. To put this in perspective, the United States could get half its electricity from wind power and the bird fatalities would be less than 1 percent of the number of birds U.S. housecats kill each year. At sites in southwestern Pennsylvania and West Virginia, however, significantly large numbers of bats have been killed by wind turbines. The industry is studying the matter to figure out how to prevent this.
U.S. Wind Energy Links:
From: An Assessment of the Available Windy Land Area and Wind Energy Potential in the Contiguous United States (Pacific Northwest Laboratory, 1991)
Estimates of the electricity that could potentially be generated by wind power and of the land area available for wind energy have been calculated for the contiguous United States. The estimates are based on published wind resource data and exclude windy lands that are not suitable for development as a result of environmental and land-use considerations. Despite these exclusions, the potential electric power from wind energy is surprisingly large. 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. Technology under development today will be capable of producing electricity economically from good wind sites in many regions of the country.
...To provide 20% of the nation's electricity, only about 0.6% of the land of the lower 48 states would have to be developed with wind turbines. Furthermore, less than 5% of this land would be occupied by wind turbines, electrical equipment, and access roads. Most existing land use, such as farming and ranching, could remain as it is now."
From: Wind Energy Resources (National Wind Coordinating Committee, Jan 1997)
"The United States is fortunate to possess one of the largest wind energy resources in the world. The amount of energy theoretically available for use has been estimated at as much as 40 times the current U.S. energy consumption. Of course, only a small fraction of this potential could be used because of constraints on available land for wind power plants, limits on the efficiency of energy extraction, cost, siting issues and other factors. Even after taking these factors into account, various studies suggest nonetheless that wind has the potential to supply anywhere from 10 percent to 40 percent of U.S. electricity needs.
...They found that the windiest areas (class 5 and above) could support enough wind power capacity to provide 18 percent to 53 percent of the electricity consumed in 1993. The lower figure represents the most severe assumptions of land use exclusion, while the upper figure represents no exclusions at all. Most of the prospective sites in these classes are concentrated in the Great Plains states. In contrast, class 3 and 4 areas are distributed much more widely around the country and, according to the study could supply from 1.7 to 6 times the current U.S. electricity demand.