FOSSIL FUEL ANALYSIS World Energy Consumption Where Energy Comes From US and World Energy Consumption

WHAT IS A FOSSIL FUEL? Most common fuels are similar to food in many respects. They contain carbon compounds and are known as fossil fuels because they are found in the earth as the end product of organic matter left behind by plants and animals and buried many years ago. Such fuels are burned in air, combining with its oxygen in a chemical reaction that produces heat. This heat can then be converted into mechanical or electrical energy. When they are burned, fossil fuels are consumed. Therefore, they are a nonrenewable energy resource.

COAL IS A FOSSIL FUEL A hydrocarbon, coal is classified in ranks, or types, according to the amount of heat it produces. This depends upon the amount of fixed carbon it contains. The ranks, in increasing order, are lignite, or brown coal; bituminous coal, or soft coal; and anthracite, or hard coal. Bituminous coal is the most abundant type.

COAL FORMATION

PEAT IS A PRECURSER OF COAL A worker cuts peat from lush peat land in Ireland. Peat is the first stage in the transformation of vegetation into coal. For hundreds of years, people have cut, dried, and burned it for heating and cooking. This compact, dark-brown material contains about one third less heating value than coal.

KINDS OF COAL MINE Drift Mine Strip Mine Three types of mines are built to excavate coal beds deeper than about 30 m (100 feet) underground. Shaft mines use two vertical shafts to reach the deeply buried coal beds. Slope mines use angled shafts to reach coal deposits that have been tilted or folded in the earth’s crust. Drift mines use a single shaft to follow coal beds back into a mountainside.

COAL MINING Coal Mine Coal Fields in the USA

COAL PRODUCING AND CONSUMING These charts show the countries that produce the most coal and the countries that consume the most coal. Coal is burned to produce electricity and to make coke for the production of steel. China produces and consumes more coal than any other country in the world.

THE GEOLOGY OF OIL AND GAS In order for a substantial natural-gas or oil deposit to form, three geologic conditions must be met. First, somewhere in the subsurface there must be a source rock that will generate the gas and oil. Second, in that same general area, there must be a reservoir rock to hold the natural gas and oil. Finally, there must be a trap in the underground reservoir rock to concentrate the gas and oil into commercially useful quantities.

OIL AND GAS FORMATION Both crude oil and natural gas are formed from ancient dead plant and animal material that lies buried in layers of sedimentary rock. Black shales--the most common source rocks--were formed from very fine-grained muds. A minimum temperature of 120o F (49o C) is necessary to start the process of natural generation of crude oil. Temperatures increase with depth. Oil is generated at temperatures between 120o F (49o C) and 350o F (177o C), which occur at depths between about 5,000 feet (1,500 meters) and 21,000 feet (6,400 meters). The area in the crust of the Earth where oil is generated from the source rock is called the oil window. Heavy oils are generated at the lower temperatures found in shallower parts of the oil window, whereas lighter oils are generated at the higher temperatures found in the deeper levels.

OIL DRILLING The rotary drilling rig uses a series of rotating pipes, called the drill string, to tap into oil reservoirs. Circulating, mud like fluid driven by a pump removes cuttings as the teeth of the drill bit dig into the rock around the reservoir. This reservoir abuts a salt dome, which has trapped a layer of oil and natural gas between itself and nonporous rock. Because they have no place to expand, the gas and crude oil are under high pressure and will tend to rush explosively out the channel opened by the drill rig.

OIL PRODUCING AND CONSUMING COUNTRIES These charts show the countries that produce the most petroleum and the countries that consume the most petroleum. Petroleum is refined into gasoline, which powers most of the world’s transportation systems. Lubricants derived from petroleum are also used in virtually all mechanical devises. The United States is the world’s second largest petroleum producer, and the world’s largest petroleum consumer.

WORLD ENERGY CONSUMPTION

WHERE ENERGY COMES FROM

US and World Energy Consumption In 1996, 375 quadrillion British thermal units (BTU) of fossil fuels were consumed worldwide. These fuels were in the form of oil, gas, and coal. The United States, with less than 5 percent of the world’s population, consumed 25 percent of the oil, 27 percent of the gas, and 24 percent of the coal.