Coal provides 54 percent of the US electricity supply. Oil is used primarily for transportation fuels, but also for power production, heat and as a feedstock for chemicals. The US imports over half of the oil we use, more than ever before. Natural gas is a relatively clean burning fossil fuel, used mostly for space and water heating in buildings and running industrial processes. Increasingly, natural gas is used in turbines to produce electricity.
Nuclear power harnesses the heat of radioactive materials to produce steam for power generation.
Nuclear power provides about 21 percent of US power, but is expected to decline as old plants retire.