Even Thomas Edison tilted at windmills. America's most prolific inventor was an early proponent of using windmills connected to electric generators to bring electricity to rural America. The electricity generated by windmills could have been stored in batteries, meaning more potential customers for Edison's inefficient incandescent bulb and other power-hungry devices. According to an article by Heather Rogers in The New York Times Magazine on Edison's efforts to promote wind power, Edison went so far as to draw up plans for windmills that would power as many as six homes. He pitched manufacturers on building a prototype in 1911, Rogers reported.

Edison's scheme never really took off, but some of us are old enough to remember when the countryside was dotted with windmills used by farmers to pump well water or power machinery. Many of those windmills rusted as family farms were subdivided into suburbs.

But growing energy costs have generated renewed interest in wind power. A recent U.S. Energy Department study found that the United States is the fastest-growing market for wind power. Europe remains far ahead in total electricity generated from wind, but the U.S. is gaining rapidly and has far more wind resources available.

U.S. wind power capacity jumped 27 percent in 2006, the largest incremental jump on record and the highest incremental capacity in the world, the U.S. study found.

"The wind power industry has entered an era of substantial growth, both globally and in the United States," said Ryan Wiser, co-author of an Energy Department report on wind power and a scientist at Lawrence Berkeley National Laboratory (Berkeley, Calif.). "The market is just exploding," said Wiser.

According to the DOE report, the U.S. ranked third globally in 2006 in cumulative wind power capacity with 11,575 megawatts. Germany was first with 20,652 MW, followed by Spain with 11,614 MW.

The study found, however, that the U.S. lags far behind global leaders Denmark, Spain, Portugal and Germany in the percentage of electricity consumption from wind power. The U.S., France and China were all under 1 percent of projected wind power production as a percentage of overall electricity consumption in 2006. Denmark leads the world with 21.4 percent of its electricity supplied by wind power.

Within the United States, the states of Texas, Washington and California lead the nation in new annual wind power capacity.

The DOE report also noted that the cost of wind turbines has been increasing since 2002, reversing a decline in the cost of wind power projects and raising the price tag for generating wind power. But rising costs have been offset by higher tower heights, improved siting and technology advances.

The biggest hurdle, experts agree, is power transmission.

"One of the greatest challenges is the siting of electric transmission corridors to support wind power generation," said Bernie Lesieutre, a power electronics professor at the University of Wisconsin, Madison, who has worked extensively on power transmission issues.

"Long lines will be needed to send 'wind by wire' from locations with the greatest potential to distant population centers," he added. "Transmission siting has long been a difficult process that often involves different state and federal agencies, and concerned private citizens' groups, any of whom may question the value of a project passing through their area for which they perceive they will not receive direct benefit."

Still, said Lesieutre, "The technology is here."