Technological advancement starting from the industrial revolution has increased the demand for energy. If we look at the history of man’s usage of energy, sun was the first energy source which provided light and heat to early humans. The discovery of fire resulted in the possibility of burning wood for cooking and heating thereby using energy. Renewable sources of energy such as sun, wind, biomass and hydropower was the only sources of energy for humans for thousands of years. As early as 4000–3500 BC wind energy was used to propel ships and windmills.
Fuel wood and dung cakes were also used for burning and producing heat for cooking. These are used even today a major source of energy in different parts of the world. In addition, from early days till today solar energy is a major source of energy (TERI, 2006). Early Egyptians collected oil that floated to the top of ponds and used it to burn for light. Coal was burned to bake clay pots by American Indians. Natural gas was used to heat sea water to produce salt by ancient Chinese (Elementary Energy Infobook, N.D.).
Today, the usage of energy has increased so much that in no other century or no millennium in the history of man was the growth in energy use as much as it is in this century. In fact, man in the 20th century used 10 times as much energy as in the thousand years before 1900 A.D. To be more specific, man has probably deployed more energy since 1900 than in all of human history before 1900. Between the dawn of agriculture and 1900 in the 100 centuries, McNeill calculates that only about two-thirds as much energy as in the 20th century was utilized by man (McNeill, 2001). The use of energy escalated during the industrial revolution in the form of fossil fuels which occurred in different stages, from the exploitation of coal deposits to the exploitation of oil and natural gas fields. Nuclear power as an energy source is only half a century old (TERI, 2006).
It is anticipated that global energy needs will to continue to grow more and more for at least the next two-and-a-half decades. World energy needs will be almost 50% higher in 2030 than that is today, with an average annual growth rate of 1.6%, if governments stick with current policies. It is estimated that in developing countries that accounts for highest economic and population, more than two thirds of the growth in world energy use will occur. Fossil fuels continue to dominate energy supplies and will account for more than 80% of projected energy demand.
Oil remains the single largest fuel and is estimated that the demand will reach 92 mb/d in 2010 and 115 mb/d in 2030. In addition natural gas demand is also estimated to grow fast and to surpass coal as the world’s second-largest primary energy source before 2015. However coal will remain a major source of energy in developing countries like India and China. Estimates say that while nuclear power’s market share may marginally decline, hydropower will remain mostly constant. In additions it is also projected that the share of non-hydro renewables, such as solar, biomass, wind, tidal, geothermal, and wave energy will remain constant at 11% (Birol, N.D.).
The demand for energy will increase substantially in the coming decades and we need to have enough resource to fulfil the needs. Hence, government policies need to promote sustainable use of energy, particularly the non-renewable energy sources as these are perishable if used unsustainably.