As reported by the Washington Post:
[A]ided in part by subsidies put in place by the Obama administration during the last economic recession, operators of wind turbines and solar panels have been able to lower costs to the point of being competitive with coal.
The country is projected this year to get more power from renewable energy than from coal for the first time, according to the Energy Information Administration. Last year, coal made up about a quarter of U.S. power generation.