What is Natural Gas?
Natural gas is a combustible, gaseous mixture of simple hydrocarbon compounds, usually found in deep underground reservoirs formed by porous rock. Natural gas is a colorless, odorless fossil fuel composed almost entirely of methane, but does contain small amounts of other gases, including ethane, propane, butane and pentane.
Natural gas is used extensively in residential, commercial and industrial applications. It is the dominant energy used for home heating, with about 51 percent of American homes using gas. Additionally, the use of natural gas is rapidly increasing in electric power generation and cooling, and as a transportation fuel.
Natural gas is the cleanest-burning fossil fuel, producing primarily carbon dioxide, water vapor and small amounts of nitrogen oxides. Other fossil fuels are coal and oil, which together with natural gas, account for about 88 percent of U.S. energy consumption.
Currently, oil provides the largest share of U.S. energy consumption, about 41 percent of the entire market. Natural gas provides about 24 percent, coal 23 percent, hydropower four percent and nuclear power eight percent. However, about half of the oil Americans use is imported; in contrast, 85 percent of the natural gas U.S. consumers use is produced domestically with the remaining 15 percent coming primarily from Canada via pipeline.
Natural Gas and the Environment
Because natural gas is the cleanest-burning fossil fuel, it can help improve the quality of air and water, especially when used in place of other, more polluting energy sources. Natural gas combustion results in virtually no atmospheric emissions of sulfur dioxide (SO2) or small particulate matter, and far lower emissions of carbon monoxide (CO), reactive hydrocarbons, nitrogen oxides (NOx) and carbon dioxide than combustion of other fossil fuels.
Natural gas is more environmentally attractive than other fossil fuels because it is composed chiefly of methane - a molecule made up of one carbon atom and four hydrogen atoms. When methane is burned completely, the principal products of combustion are carbon dioxide and water vapor. In comparison, oil and coal compounds have much more complicated molecular structures. They include a higher ratio of carbon, as well as various sulfur and nitrogen compounds, and do not burn as cleanly. Coal and industrial fuel oil combustion also produce ash particles, which do not burn at all; however, they can be carried into the atmosphere. Because natural gas burns cleanly, its use can be an effective means of controlling pollution.