The U.S. power grid could become less reliable if too much electricity comes from renewable energy and natural gas, according to a study from the Department of Energy.
But not everyone is buying it. Environmentalists suspect the Trump administration is just trying to prop up an ailing coal industry.
Energy Secretary Rick Perry called for the study in the spring. The report doesn't say there is a grid reliability problem now — only that one could develop if more coal and nuclear power plants shut down.