http://blog.crowncapitalmngt.com/what-fossil-fuel-really-do-to-america/

Fossil fuels—coal, oil, and natural gas—are America’s primary source of energy. America’s annual consumption of fossil fuels grown rapidly. 89 % of these consumption are consumed by boilers, transportation, residential usage, fuels for direct heating of process. The balance is used for feed-stocks, raw materials, and other miscellaneous uses. And most of the dirty fuels such as coal and residual oil go into boilers.

Fuel burned are by far the largest single source of air pollution. This pollution is from sulfur oxide. It is also a significant source of particulate matter and nitrogen oxides. Boiler combustion is sufficiently important to warrant the effort to analyze the complete nature of the problems.

Fuel consumption in boilers is divided into three sectors: utility boilers producing steam for generation of electricity which is actually consuming probably 59%, industrial boilers producing steam or hot water for process heat,generation of electricity or space heat consuming about 24%, and boilers for space heating for commercial and institutional facilities consuming the 17%.

http://www.youtube.com/watch?v=mmmpIYqoi7w&feature=youtu.be

The economic development of one country is dependent upon the ability of the authorities to set up a highly suitable, competitive and reliable electricity sector. Why is natural gas better than coal boilers?
Only when there is extreme environmental pressure or substantial reduction in loads that conversion from coal to 100% natural gas is possible.
Not until the 20th century until natural gas was used for production of energy, it was dismissed as a useless byproduct of crude oil production until then. But now natural gas accounts for 23 percent of the world’s energy consumption and still growing. The International Energy Agency predicts that the demand for natural gas will grow by approximately 44 percent through 2035.
Natural gas is the cleanest-burning conventional fuel not to mention it has been one of the most economical energy sources. It is an environmentally friendly and efficient source of energy. It produces lower levels of greenhouse gas emissions than heavier hydrocarbon fuels such as coal and oil. Natural gas fuels electric power generators, heats buildings and is used as a raw material in many consumer products, such as those made of traditional plastics. However, natural gas has never been a cheaper fuel than coal.

Coal is one of the longest-used and is considered as the most abundant fossil fuels on Earth. Coal mining has been going on since then 17th century. Coal burning boilers have also been around for a long time, and while they may not always be popular, these machines have some definite advantages in terms of costs and simplicity.
Because it is the most abundant it is the cheapest form of fossil fuel to burn. But coal boilers on the other hand have harmful effects on the environment and human health. Its emissions contain sulfur combines with air to create the poison gas sulfur oxide. When this gas releases into the atmosphere, it causes polluting rain. Extracting coal from mines further damages soil and water resources, adding to the disadvantages of using coal burning boilers.