The sources of the energy that people use the world over fall into two general categories: renewable and nonrenewable. While the supply of renewable resources, such as sunshine and wind, is virtually limitless, nonrenewable resource supplies are finite. Some nonrenewable resources, including oil and coal, are the product of millions of years of conversion from fossils, the buried remains of ancient plants and animals. Others, such as uranium, are not categorized as fossil fuels but are still rare and nonrenewable. (See References 1)
Liquid petroleum --- crude oil --- is the only nonrenewable resource in fluid form. A fossil fuel that is being used up faster than new reserves are discovered, the oil supply may only last through the middle of this century. Industrial nations, with the U.S. far in the lead, are the biggest consumers of crude oil. Gasoline, heating oil, and diesel fuel are the primary uses of the resource, although manufacturers utilize oil as the base for such products as plastics and industrial chemicals. (See References 2)
Natural gas reserves often share space with underground oil reserves, so the two nonrenewable resources are often extracted at the same time. Natural gas is primarily composed of methane, but contains ethane, propane and butane as well. Once drillers extract natural gas, processing plants remove the propane and butane for use as liquified petroleum gas (LPG), a household and industrial fuel. Consumers use it as a cooking fuel, for heating and sometimes for vehicle fuel. According to the current usage statistics and the volume of world reserves, the supply of natural gas should last another century. (See References 2)
Coal reserves represent the largest stockpile of nonrenewable resources in the world. Coal is the product of millions of years of pressure on original organic matter from plants buried underground. Bituminous coal, which is the type most commonly found in U.S. reserves, is approximately 85 percent carbon and 3 percent water. More than half of the electricity used in the U.S. is generated in coal-burning plants, a process that releases sulfur dioxide, a greenhouse gas, into the atmosphere. The global supply of coal, given the current rate at which it is used, should last at least two more centuries. (See References 2)
Tar Sand and Oil Shale
Tar sand is tarry oil that comes from sedimentary rock. Reserves of this nonrenewable resource are only plentiful enough to supply energy for 15 years or so. Extracting tar sand is a labor-intensive process that uses up 1/2 barrel of oil for every barrel of tar sand recovered. Oil shale extraction is similarly difficult and energy-intensive. More plentiful than tar sand, current oil shale reserves could fuel international demand for up to a century. (See References 2)
Uranium is a radioactive chemical element that naturally occurs in some groundwater, soil and rock. Uranium was deposited in the earth from extraterrestrial events, probably super novae, that occurred billions of years in the past. The primary use of uranium is nuclear energy production. Worldwide uranium reserves are more abundant than mercury, cadmium, and silver reserves. However, U-235, the fuel used in nuclear plants, is very rare. (See References 3) While nuclear power generation does not emit greenhouse gasses, radioactive byproducts create environmental hazards (see References 2).
Lynne Haley Rose has written extensively for Internet publications on topics in business, finance, fitness and renewable energy. Her poetry has been honored by the Washington Poets Association and published in "Poetry Northwest," "Willow Springs" and online at Fogged Clarity. She has a Bachelor of Arts from Gonzaga University and a Master of Fine Arts in creative writing from Eastern Washington University.
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