Which Energy Sources Are the Dirtiest?

Estimated metric tons of carbon dioxide emission equivalents from generating one gigawatt-hour of electricity

A bar chart of the emissions resulting from each energy source generating the same amount of electricity, showing oil and natural gas to be the dirtiest energy sources after coal.

Note: The chart shows the average emissions per gigawatt-hour of electricity over the life cycle of a power plant.

Source: Our World in Data aggregation of findings from scientific studies.