The role of coal

摘要

In 2006,some 5 billion t of hard coal and 0.9 billion t of lignite were extracted and consumed worldwide.The calorific value of the mined coal is 4.4 billion t of coal equivalent (tce -1 tce = 29,308 kJ).In total,global primary energy consumption is almost 16 billion tce,of which coal has a 28% share and 26 percentage points of which are accounted for by hard coal and two percentage points by lignite.This gives coal slot two in the ranking of the most important energy carriers worldwide - after mineral oil and ahead of natural gas.