Of all the fossil fuels, coal is by far the most plentiful in the world. It has been estimated that, as at 1996, there are around one thousand billion tonnes of total coal reserves economically accessible using current mining technology, approximately half of it being hard coal. At 1998 production levels, reserves are sufficient to last over 200 years.

World oil and gas reserves are estimated at just 40 years and 60 years respectively, at current production levels.