For centuries now coal has been man’s main source of heat  and energy.  However, coal suffered a huge decline in the industrial age, when the oil industry took over and the world opted for liquid fuels.  Adding to this decline was the fact that gaseous fuels, initially the by-product of oil, also grew in importance.  The substitute for coal became oil, and it defeated coal in most of its traditional markets.  Oil not only dominated the world’s transport scene, but it also came to have widespread use in domestic and industrial heating and for power generation.  In short, in many countries, oil became the prime source of energy

On a global basis, oil and gas are still the most widely-used fuels.   However, since the oil price explosions of the 1970s, coal was restored as the dominant fuel for power stations and cement works.  Coal has steadily come back into favour.