In recent decades energy production has shifted with similar speed: Hydraulic fracturing was first invented in the 1940s, but when combined with horizontal drilling in the 2000s it ignited a boom in oil and gas production in the United States. Renewable energy has also grown rapidly as technology has improved: U.S. wind power produced just 70 trillion BTUs of energy in 2001, yet by 2010 had risen to 924 trillion BTUs — more than 13 times higher. By 2014, wind generated more than 181 gigawatt hours of power, up 8% from 2013’s total. Looking forward, the United States expects to get 35% of its electricity from renewable sources by 2050, and research indicates that 80% is feasible with current technology.