The Invenergy Judith Gap wind farm in central Montana. 14,300 acres in Wheatland County 100 miles east of Helena. The wind farm produces 135 MW of power from 90 GE 1.5 MW sle wind turbines. The blades are made in Brazil and the towers are made in South Korea and China. | William Campbell/Getty Images

The US Just Surpassed a Major Renewable Energy Milestone

Wind and solar energy supplied 10 percent of the nation's energy in March for the first time.