A combination of terrain and seasonal weather patterns has given Minnesota and the region an abundance of wind to use for the generation of electricity. Here's a look at our wind power potential: Wind gauges measure a site's potential, preferably over a full year. The data are displayed in charts called "wind roses."

• Points of the "petals" on the compass show where the winds came from.

• Size of the "petals" on the concentric circles show how often wind came from that direction.

Minnesota's wind industry was essentially born in the 1990s, when the Legislature mandated that Northern States Power (now Xcel Energy) generate 425 megawatts of wind power or purchase it from other companies by 2003. In 1994, NSP erected 73 wind turbines on Buffalo Ridge with a combined capacity of 25 megawatts -- an amount that can now be achieved with 11 of the nearly 1,000 turbines across the state. The state now requires utilities to generate at least 25 percent of their electricity from renewable sources by 2025. For Xcel, the quota is 30 percent by 2020. An estimated 3,000 new turbines will be needed to meet that goal. An area with excellent wind power

potential can still produce poor results if

a wind turbine is not properly situated.

Generally, higher winds are faster winds. But turbulence caused by terrain, trees, buildings, and even other wind turbines can sap the strength of the wind. Turbine sites must be carefully selected.

The turbine design shown above is the largest and most powerful in use in Minnesota. Wind farms in Mower and Cottonwood Counties have dozens of these giants.

Despite long delays in the government approval process and a shortage of turbines for green-lighted projects, Minnesota's wind industry has exploded in the past 14 years. Sources: Minnesota Department of Commerce, American Wind Energy Association, WindLogics, N.Y. Times

Because wind power must be distributed as it is produced, the growing number of wind farms has overwhelmed the state's power transmission lines. New lines are costly and take time to build. A new high-power line in the Buffalo Ridge area should help reduce wasting wind power that can't be delivered. By far, the richest area of wind power in Minnesota is Buffalo Ridge, which rises hundreds of feet above the surrounding plains and faces into the prevailing winds. After 14 years of development, the ridge is nearly saturated with wind farms.

To see an interactive graphic on wind energy go to: startribune.com/science