Natural gas is a highly combustible fossil fuel primarily composed of methane, though it does contain various other hydrocarbons. According to the International Energy Agency's "World Energy Outlook 2000" report, its use worldwide is expected to increase from 18 percent of total fuels consumed in 1971 to 26 percent by 2020.
Natural gas is invisible and odorless, with the gas methyl mercaptan added during production to add a spoiled-egg scent to assist in detecting leaks. In addition to containing between 70 to 90 percent methane -- each molecule of which contains one carbon and four hydrogen atoms -- it also contains less than 20 percent ethane, propane and butane, as well as trace amounts of carbon dioxide, nitrogen, oxygen, hydrogen sulfide and other, rarer types of gas.
According to the U.S. Energy Information Administration, about 24 percent of American energy needs in 2002 were met by natural gas in a variety of ways. The EIA claims that 24 percent of total consumption was used to generate electricity, 32 percent was used in industrial applications, 14 percent was used commercially and about 22 percent was used residentially -- with about 8 percent used in other ways. At home, natural gas is most commonly used for cooking and heating.
The U.S. Department of Energy considers natural gas to be the one of the cheapest fuels on the market, behind utility-generated electricity, propane, kerosene and no. 2 heating oil. This is true for residential and all other applications. The American Gas Association estimated in 2002 that it would cost twice as much for an electric water heater to fill a bathtub as it would for a natural gas heater. Because of its low cost, natural gas is a popular energy source: In 2003, according to the U.S. Census, 70 percent of new home construction used natural gas heaters.
Natural gas burns more efficiently and pollutes the environment less than other common fossil fuels used to generate electricity. The U.S. Energy Information Administration's "Natural Gas Issues and Trends 1998" report shows that coal and oil produce more carbon dioxide, nitrogen oxides, sulfur dioxide and particulate matter when burned. Natural gas also contains no mercury byproducts, as opposed to both oil and coal. These emissions, considered greenhouse gases, are considered to be the chief causes of global warming, smog and acid rain, among other environmental problems.
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Properties of Liquid Natural Gas
Liquid natural gas (LNG) is a natural gas that has undergone condensation to become a liquid. At an atmospheric pressure of 14.7...