Fossil Fuels

Fossil fuel is a general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years.

When generating electricity, energy from the combustion of fossil fuels is often used to power a turbine. Older generators often used steam generated by the burning of the fuel to turn the turbine, but in newer power plants the gases produced by burning of the fuel turn a gas turbine directly.

With global modernization in the 20th and 21st centuries, the thirst for energy from fossil fuels, especially gasoline derived from oil, is one of the causes of major regional and global conflicts. A global movement toward the generation of renewable energy is therefore underway to help meet the increased global energy needs.

Limited Resources

In addition to damaging the environment when burned, fossil fuels are a finite resource.

Levels (reserves) (EIA oil, gas, coal estimates)

• Oil: 1,050,691 to 1,277,702 million barrels
• Gas: 6,040,208 - 6,805,830 billion cubic feet
• Coal: 1,081,279 million short tons

Years of production left in the ground with the most optimistic reserve estimates (Oil & Gas Journal, World Oil)

• Oil: 32 years
• Gas: 72 years
• Coal: 252 years

Damaging Resources

Coal

Coal is a fossil fuel extracted from the ground by underground mining or open-pit mining (surface mining). It is a readily combustible black or brownish-black sedimentary rock. It is composed primarily of carbon along with assorted other elements, including sulfur. Often associated with the Industrial Revolution, coal remains an enormously important fuel and is the largest single source of electricity world-wide. In the United States the coal power plants generate 50% of the electricity produced. In the UK, coal supplies 28% of electricity production (as of October 2004). In the UK this has been decreasing since the late-1990s with natural gas replacing coal as the primary electricity generating fuel.

Emissions from coal-fired power plants represent the largest source of carbon dioxide emissions, a primary cause of global warming. Coal mining and abandoned mines also emit methane, another cause of global warming. Since the carbon content of coal is much higher than oil, burning coal is a more serious threat to global temperatures. Many other pollutants are present in coal power station emissions. Some studies claim that coal power plant emissions are responsible for tens of thousands of premature deaths annually in the United States alone.

There is much work being done to better utilize existing technology and develop new technologies to eliminate emissions from coal-fired power plants.FutureGen is an initiative to build the world's first integrated sequestration and hydrogen production research power plant. The $1 billion dollar project is intended to create the world's first zero-emissions fossil fuel plant. When operational, the prototype will be the cleanest fossil fuel fired power plant in the world.

Oil

Petroleum, or crude oil, is a black, dark brown or greenish liquid found in porous rock formations in the earth. It is composed mainly of mixtures of chemical compounds of carbon and hydrogen with or without other nonmetallic elements such as sulfur, oxygen, and nitrogen."

Petroleum is also the raw material for many chemical products, including solvents, fertilizers, pesticides, and plastics. 88% of all petroleum extracted is processed as fuel; the other 12% is converted into other materials such as plastic.

Gas

The primary component of natural gas is methane (CH4), the shortest and lightest hydrocarbon molecule. It also contains heavier gaseous hydrocarbons such as ethane (C2H6), propane (C3H8) and butane (C4H10), as well as other sulphur containing gases, in varying amounts. Natural gas also contains and is the primary market source of helium.

Natural gas burns cleaner than other fossil fuels, such as oil and coal, and produces less greenhouse gas per unit energy released. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal.

However, it is the most significant source of indoor air pollution responsible for generating illness, surpassing even pesticides or passive tobacco smoke. For the chemically susceptible individual, this may be the worst form of fuel. Dr. Gerald Ross, M.D., President of the American Academy of Environmental Medicine, writes that, "Traditionally, natural gas is a pollutant chemical that can worsen both classical allergy and chemical sensitivity." He further states, "patients with complex allergies and sensitivities will have only limited success with their treatment programs, if they are living in a home that has natural gas or if they are in an area where there is natural gas transportation or leakage." (3 Jan., 1997).

In the past, the natural gas which was recovered in the course of recovering petroleum could not be profitably sold, and was simply burned at the oil field (known as flaring). This wasteful practice is now illegal in many countries, as it adds greenhouse gases to the earth's atmosphere. The gas is now re-injected back into the formation for later recovery.

For more information about Fossil Fuels see http://en.wikipedia.org/wiki/Fossil_fuels .