Fossil fuels are carbon and hydrocarbon compounds formed over millions of years from the organic remains of prehistoric plants and animals. There are three major forms of fossil fuels - coal, oil and gas. At present these fossil fuels are the major source of our energy needs, but these fossil fuels are non-renewable sources and are being consumed quickly. Although they may take millions of years to form, in the past 100 years there has been a tremendous increase in their consumption. Coal forms when plant remains decompose under water and are then compressed and heated underground for a very long time. Coal is the major contributor to the world’s energy use. About 23% of the world’s total energy comes from burning coal, with 38% of world’s electrical energy generated from coal. But on ecological basis, coal is a dangerous source of energy. Coal as well as the other fossil fuels is composed of carbon and hydrogen. In addition sulfur and nitrogen are present in coal. On combustion the sulfur in particular is released into the atmosphere which in turn causes air pollution and acid rain. Carbon dioxide that is emitted on combustion of coal is a greenhouse gas that increases global temperature. There are several new technologies use to improve the efficient burning of coal. Gasification is one that combines coal with oxygen and steam to produce Syngas, a mixture of hydrogen and carbon monoxide. This gas is cleaned to remove impurities like sulfur and is used to produce electricity. The improved efficiency of gasification, decreases the carbon dioxide emission from coal by 25% and the global CO2 emission by 6%. Coal is quite abundant compared to oil and natural gas. Current coal could last for 200 years or more. Due to the scarcity of oil supplies, worldwide coal use will increase. Oil is formed from the remains of marine microorganisms deposited on the sea floor. After millions of years the deposits end up in rock and sediment where oil is trapped in small spaces. It is noe believed the demand for oil has now exceeded the supply, the current discovered oil could last until 2040. Most of the oil is used for transportation. We can decrease the oil use By increasing the fuel efficiency of our vehicles By creating next generation of vehicles that no longer require oil. By using ethanol along with gasoline. Natural gas is clean when compared to coal and oil. It is also formed from the remains of marine microorganisms. Current reserves of natural gas could last until about 2075 at the current rate of consumption. Unconventional gas production (gas from shale, coal beds) has increased the gas production by 15%. Horizontal drilling and directional drilling technology is used to increase the chances of gas being found while drilling for oil. Fossil fuel prices will increase in the coming century because of scarcity and the gap between production and consumption. The following table illustrates the quantity of pollutants produced by each of the fossil fuels. Fossil fuel emission levels Pounds per billion Btu of energy input Pollutant Coal Oil Natural gas Carbon dioxide 208,000 164,000 117,000 Carbon monoxide 208 33 40 Nitrogen oxides 457 448 92 Sulfur dioxide 2591 1122 1 Particulates 2744 84 7
Posted on: Wed, 21 Jan 2015 11:43:50 +0000