Demand for coal rises
16 December 2013 Last updated at 09:54 GMT
Pressure to reduce carbon emissions has done little to stop the rise in demand for coal, particularly in growing economies like China and India.
The International Energy Agency says use of coal has doubled in the past 20 years - making it is as important to the energy market as the next two sources, gas and renewables, put together.
Philip Hampsheir reports.