The United States is well on its way to becoming largely self-sufficient in oil and gas and could overtake Saudi Arabia as the world's biggest supplier of hydrocarbons by 2020. Even if U.S. energy independence is still some time away, this is nonetheless a stunning turnaround from decades of U.S. dependence on imported energy sources and all the attendant geopolitical concerns. The change has been driven in part by innovative methods of exploration and extraction of fossil fuels such as shale gas from hydraulic fracturing. In a development entirely unforeseen five years ago, this has caused natural gas supplies in the United States to soar and prices to drop. Europe, in contrast, must pay four to five times more for its natural gas and has become one of the biggest importers of U.S. coal, which is experiencing a sharp decline in its share of U.S. electricity generation as power is increasingly supplied by natural gas. This increasing availability of cheap electricity is helping to bring new vigor to the U.S. economy and there are signs of new manufacturing life in old industrial regions as energy-intensive industries like petrochemicals are finding the United States a more competitive place to do business.