With a key federal tax incentive about to expire, the U.S. installed a 5.5 gigawatts of wind power in December to cap off a year that saw a record 13.2 gigawatts of wind energy come online, according to a report released Friday by research firm Bloomberg New Energy Finance. The U.S. now boasts a total of 60 gigawatts of wind energy, accounting for 6% of the nation’s total generating capacity. According to Bloomberg New Energy Finance, wind power prices have dropped more than 21% since 2010. Falling prices and the looming expiration of the production tax credit, which pays a premium for wind energy, unleashed a wind farm building boom last year. “It’s clear that the economics, aided by the PTC, drove wind growth in 2012,” Amy Grace, a wind analyst with Bloomberg New Energy Finance, said in a statement. “Eleven gigawatts of capacity was built in states without any near-term state mandated demand.

The report finds that in 2011, roughly 6,800 megawatts (MW) of new wind power capacity was added to the U.S. grid, a 31 percent increase from 2010 installations.  The United States’ wind power capacity reached 47,000 MW by the end of 2011 and has since grown to 50,000 MW, enough electricity to power 13 million homes annually or as many as in Nevada, Colorado, Wisconsin, Virginia, Alabama, and Connecticut combined. The country’s cumulative installed wind energy capacity grew 16 percent from 2010, and has increased more than18-fold since 2000.  The report also finds that six states now meet more than 10 percent of their total electricity needs with wind power.

Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.

The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater.