Power-laden winds sweep North America.

There's ample wind in the United States to supply all the country's electricity, according to Mark Z. Jacobson of Stanford University and his colleague Cristina L. Archer. They base that claim on data from about 2,400 locations in North America. Wind power can be produced economically if the average wind speed at windmill height exceeds 6.9 meters per second, the researchers note in an upcoming Journal of Geophysical Research (Atmospheres). Wind blows that strong in broad swaths of the Great Plains and the continent's coasts. In the map above, dots other than light- and medium-blue shades mark potential wind-power areas. All that's needed for U.S. utilities to generate as much electrical power as the nation now consumes, the researchers calculate, are around 750,000 1.5-megawatt wind turbines.