How Is Electricity Generated From Fossil Fuels?

Coal Fired Power Plant

A coal fired power plant burns coal to produce electricity. Coal is loaded into the boiler and ignited to heat a supply of water from a nearby source to over 540 degrees Celsius (1,040 degrees Fahrenheit). The water does not boil because it is pressurized to around 1,800 pounds per square inch. The water produces steam which is kept pressurized and used to turn a turbine which turns a generator. The water is then cooled and released back into the river and electricity sent to a substation for distribution. According to the Tennessee Valley Authority their Kingston Power Plant near Knoxville burns around 14,000 tons of coal a day producing enough electricity to power 700,000 homes. Burning coal is the most popular method of generating electricity in America - according to the U.S. Energy Information Administration almost 45 percent of electricity is sourced from coal.

The second most used method of producing electricity in America is burning natural gas. Beneath the Earth's surface decaying plants and animals break-down under intense heat and pressure producing pockets of gas containing carbon. This gas is extracted and processed to remove impurities such as hydrogen sulfide, helium, carbon dioxide, hydrocarbons and moisture. It is then transported via pipeline to the power plants for burning. Electricity can be generated in a similar way to coal fired power plants--by heating pressurized water and using steam to power a turbine or, more commonly, used with a combustion turbine which mixed the gas with air and burns it in a similar fashion to a car engine. A more efficient type of combustion turbine is able to generate electricity by using the exhaust fumes to turn a second turbine and generator.

Oil or petrol is mostly used for transportation or home heating but is occasionally used to generate electricity. The U.S. Energy Information Administration estimates around one percent of electricity produced in America comes from burning oil or petrol. Like coal and some natural gas power plants it is burned to create steam from pressurized water to power a turbine and generator. Against the national trend, the state of New York generates around eight percent of its electricity by burning oil, according to Power Scorecard--a website which rates the environmental impact of electricity products.

Burning fossil fuels like coal, natural gas and oil produces a number of polluting substances which are released into the air. Among these are carbon dioxide, sulfur dioxide, methane, nitrogen oxides and mercury compounds. Carbon dioxide is known to collect in the Earth's atmosphere and contribute to global warming and climate change. An estimated five tons of carbon dioxide a year is released into the atmosphere by each person in the United States through fossil fuel consumption. Carbon dioxide is absorbed by plants through photosynthesis but the rate of release worldwide is much more than can be absorbed by plants.

Fossil fuels are considered non-renewable because it cannot be replenished on a human time frame. This means that eventually Earth's coal, natural gas and oil reserves will be depleted and no more electricity will be able to be produced in this way. According to the U.S. Department of Energy coal reserves are estimated at 286 billion tons in the United States of which 43 percent, or 122 billion tons, is currently accessible. 2003 estimates put American consumption of coal at 1.1 billion tons a year, meaning currently accessible coal will be used up within 112 years.

More stark is American consumption of oil which the Department of Energy in 2003 estimated at 7.3 billion barrels a year out of national reserve of 143 billion barrels, which would lead to depletion in under 20 years.