The United States has surpassed 50 gigawatts, or 50,000 megawatts, of installed wind energy capacity, the American Wind Energy Association announced this week.

Iowa leads the nation in the number of wind energy equipment manufacturers and wind-related businesses, and by the end of 2012 the state is projected to have close to 5,000 megawatts of installed capacity. Iowa was the first state to exceed 20 percent of its electrical generation from wind. 

A production tax credit for utility-scale wind operations is set to expire at the end of this year, however, which has caused many wind energy companies to suspend plans to install more wind turbines next year. On Aug. 2, the Senate Finance Committee voted to extend the tax break, which must still be passed by the full Senate and the House of Representatives.