Environmental Engineering Reference
In-Depth Information
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Proven reserves in the United States at the end of 2008 were 19,121 million barrels of crude oil
and 244,656 billion cubic feet of dry (consumer-grade) natural gas (USEIA 2011a, 2010b). U.S.
crude oil reserves have continued to decline since the 1970s, while reserves of natural gas have
increased steadily since price deregulation in 1998.
The United States consumed 19.1 million barrels per day of petroleum products in 2010 (USEIA
2011e), comprising about 37 percent of all energy used, more than from any other energy source
(USEIA 2011a, Figure 2.0). That represented about 22.4 percent of the 85.3 million barrels per
day consumed worldwide (USEIA 2011e). The United States also consumed 23,775 billion cubic
feet of natural gas (methane) in 2010, comprising about 24.6 percent of energy used nationally
(USEIA 2011a, Figure 2.0). That represented about 21 percent of the estimated 112.9 trillion cubic
feet of natural gas consumed worldwide in 2010 (USEIA 2011d).
Combustion of petroleum products is used for transportation of people, goods and services, to
heat buildings, and to produce electric power. About 71 percent of total U.S. petroleum consump-
tion is for transportation (USEIA 2011a, Figure 2.0). Gasoline is used in automobiles and light
trucks; diesel fuel is used in heavy construction equipment, trucks, buses, tractors, boats, trains,
and some automobiles; and jet fuel is used in airplanes.
Heating or fuel oil is used to heat homes and buildings, for industrial heating, and for producing
electricity. Liquefied petroleum gases are mixtures of propane, ethane, butane, and other gases
produced at oil refineries and natural gas processing plants. Propane is used in homes for space
and water heating, clothes drying, and cooking and by farmers for heating greenhouses, livestock
housing, and drying crops. The chemical industry uses about half of all propane consumed in
the United States as a raw material feedstock for making plastics, nylon, and other materials. In
addition, liquid petroleum is used as feedstock for production of plastics, polyurethane, solvents,
asphalt, and hundreds of other products. Most of the natural gas consumed in the United States is
produced in the United States, but about 16 percent is imported, mostly from Canada via pipelines
(USEIA 2011a, Table 6.3). About 11.5 percent of imported natural gas was shipped to the United
States as liquefied natural gas in 2010 (USEIA 2011d).
The oil and natural gas fuel cycle, shown in
Figure 4.1,
includes exploration, drilling, well
development and completion, transportation, refining and processing, reclamation of wellhead
disturbances, utilization, and disposal of waste by-products. Human exposure to toxic, hazard-
ous, and flammable materials is associated with each of these activities. Although there are some
variations in the initial parts of the fuel cycle based on whether the fuels are found under land or
water, oil and natural gas are often found together and pumped from the same wells, so their costs
are sufficiently similar as to warrant treatment in a single chapter.
Oil and natural gas are often associated with coal deposits, in or below the coal. All coal deposits
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