The sun pours on to our planet each day many times more energy than we need. We see this energy in a variety of forms, ranging from solar radiation, through wind and waves, to trees and vegetation which convert the sun's rays into plant biomass. In addition there is an enormous amount of energy in the materials of the earth's crust. The challenge has been to convert these almost boundless resources into useable forms of energy. Coal was the first fossil fuel to be widely used industrially and to increase people's standard of living.
Oil is a convenient source of energy.
Because of its easy availability and low price, it played an important role in the economic development of many countries during the past century. At present, oil remains the major source of primary energy for some countries. Today natural gas is widely used alongside coal and oil, as a very versatile fuel. As demand for fossil fuels grows, we are using the technological base they have provided to increase our use of renewable energy sources. Electricity demand is growing twice as fast as overall energy demand in all parts of the world.