Currently, Minnesota Power, which serves 144,000 customers, plans to buy half the output of three new wind generators at the Chandler Hills Wind Farm in southwestern Minnesota owned by utility Great River Energy, based in Elk River, Minnesota.

Also this week, power company UtiliCorp United Inc. , based in Kansas City, Missouri, said that it activated the first wind turbines near Montezuma, Kansas, at a wind farm owned and operated by FPL Energy, a unit of Juno Beach, Florida-based FPL Group Inc. and one of the biggest U.S. players in the nascent U.S. windpower market.

UtiliCorp will buy all the power produced at the farm, which is capable of generating 110 megawatts of electricity when construction is completed at the end of the year, for customers of its WestPlains Energy utility in Kansas, as well as customers of its Missouri Public Service and St. Joseph Light & Power utilities in Missouri.

These projects have been a long time coming. Damaged by failures that hurt early U.S. backers and by critics who saw windmills as an eyesore and as a danger to birds, windpower still only provides the United States with less than 1 percent of its energy.

But worldwide, it is the fastest-growing area of energy generation, with year-on-year growth of 25 percent, and it is projected that the U.S. market will see 1,500 MW of new capacity installed this year.

Wind turbine technology is ideal for flatlands like those found in the Dakotas, Kansas and Texas, as well as where wind is drawn off bodies of water such as the Great Lakes, the Gulf of Mexico or the Pacific Ocean off California's coast.

In July, oil giant Royal Dutch/Shell Group announced an agreement to buy its first commercial wind farm, a 50-megawatt project in Wyoming.