During the Carboniferous Era some 300 million years ago lush tropical plants grew and then
geological changes crushed and compressed the plants. With time they were converted to carbon
in its many forms which are mainly coal, oil and natural gas. Continental drift then distributed
these storehouses of energy around the globe, near to where our various modern civilizations
then developed. 306 million years ago (U.S. Geological Survey)
Reserves of coal are estimated to be 8 x 1012 tonnes with annual consumption of 5x 109
tonnes. <US Global Change Research Program>. It is unlikely that we will run out of easily
accessible coal deposits in this century. Because coal is such a low cost source of energy it is
likely to remain an attractive energy source for producing electricity and for refining metals.
<Intergovernmental Panel on Climate Change>.
Next: Pulverized Coal