This chapter covers conditions and trends through calendar year 1998 using data and information available as of December 31, 2000.
Remarkable changes in the energy arena have occurred in the past half of the 20th century. The U.S. population grew by 82 percent while the consumption of energy increased by 194 percent. At the end of 1998, the average amount of energy used per person in one year was 82 percent greater than 50 years ago. At mid-century, the United States was nearly self-sufficient in petroleum and a net exporter of natural gas; coal came primarily from underground mines; nuclear electric power had not been developed; and industry used twice as much electricity as residences did. Things are much different now, for example:
TRENDS
Energy Reserves
The United States was essentially self-sufficient in petroleum until the 1950s and in natural gas until the late 1980s, when consumption began to outpace production. Over the 1977-1998 period, proved reserves of crude oil and natural gas in the United States fell substantially and imports rose to make up the difference. Crude oil reserves, estimated at 31.8 billion barrels in 1977, were down to 21.0 billion barrels by 1998 (Figure 9.1). Natural gas reserves, which were estimated at 207.4 trillion cubic feet in 1977, fell to 164.0 trillion cubic feet in 1998 (Figure 9.2).
The demonstrated reserve base of coal in the United States, as of January 1, 1997, contained an estimated 508 billion short tons. However, only 54 percent of this reserve base is believed to be recoverable over time (17 percent of the total reserve is presently inaccessible for mining and only 66 percent of the accessible reserve can actually be recovered by mining). Recoverable coal reserves at producing mines in 1998 totaled 19,311 million short tons, down 1.8 percent from 1989. Wyoming leads in reserves among the 27 coal-bearing states with 7,220 million short tons, followed by West Virginia (1,908 million short tons), New Mexico (1,385 million short tons), Montana (1,191 million short tons), Kentucky (1,175 million short tons), and North Dakota (1,170 million short tons).
U.S. uranium reserves have remained fairly stable for the last eight years. In 1998, these reserves by forward cost category totaled 276 million pounds of U3O8 at $30 per pound, 923 million pounds of U3O8 at $50 per pound, and 1,452 million pounds of U3O8 at $100 per pound.
U.S. Energy Production
Fossil fuels have dominated U.S. energy production since the early part of the 20th century, but the relative shares have changed (Figure 9.3). At the end of World War I, coal accounted for 75 percent of U.S. total energy use, but by World War II had relinquished its place as the premier fuel to growing use of petroleum. Coal regained the position of top energy source in the early 1980s, and has retained it ever since, primarily due to growing use by electric utilities. Petroleum got a major boost with the advent of mass-produced automobiles in the early part of the 20th century. Oil production from domestic reserves rose to the 20-22 quadrillion Btu (quad) range during the 1970s and 1980s, but declined to about 13 quads in the late-1990s. Natural gas was used extensively as a lighting fuel until the rapid development of electricity at the turn of the 20th century; now it is used primarily as a heating source. Domestic production peaked in the 1970s, then fell steeply through the mid-1980s before stabilizing in a range of 17-19 quads in the 1980s and 1990s. Nuclear energy production has grown from negligible production in 1960 to 7.2 quads in 1998.
Some renewable energy sources, such as water, wind, and biomass, have been used for centuries. Hydropower production has more than doubled, from 1.43 quads in 1949 to 3.39 quads in 1998, to now represent almost 5 percent of total U.S. energy production. Most of the rest of U.S. renewable energy production comes from biomass such as wood products, municipal solid waste, agricultural waste, landfill gas, and other waste. Geothermal, wind, and solar supply only a very small fraction of total U.S. energy production.
U.S. Coal Production
U.S. coal production has undergone substantial changes in this century in both mining methods and mine location.
Over the past several decades, coal production shifted from primarily underground mines to surface mines. In addition, the coal reserves of Wyoming and other areas west of the Mississippi River underwent tremendous development (Figure 9.4). Since 1960, coal production in the West has grown dramatically, from 21 million tons in 1960 to 547 million tons in 1998, to nearly equal that produced east of the Mississippi. Production in the East has remained fairly stable since 1970.
Technological improvements in mining and the shift toward more surface-mined coal have led to great improvements in coal mining productivity. In 1998, U.S. production of coal reached a record-high level of 1.12 billion short tons and was second worldwide after China. Surface mining produced 60 percent of this record quantity (Figure 9.5).
Nearly 90 percent of all coal consumed is used to produce electricity. Coal-fired electric generating units emit gases that are of environmental concern. In 1998 U.S. carbon dioxide emissions from the combustion of coal for electric utility generation were nearly half a billion metric tons of carbon, 32 percent of total carbon dioxide emitted from all U.S. fuel sources.
Petroleum Production and Imports
Until the 1950s, the United States produced nearly all the petroleum it needed. But by the end of the decade the gap between production and consumption began to widen and imported petroleum became a major component of the U.S. petroleum supply. After 1992, net imports exceeded production. Today the United States produces about 8 million barrels per day while importing nearly 10 million barrels per day (Figure 9.6). The five leading suppliers of petroleum to the United States in 1998 were Venezuela, Canada, Saudi Arabia, Mexico, and Nigeria.
Natural Gas Production
The development of steel pipelines, which allowed large volumes of gas to be easily and safely transported over many miles, launched the modern natural gas industry. The first all-welded pipeline over 200 miles in length was built in 1925, from Louisiana to Texas. U.S. demand grew rapidly thereafter, especially following World War II. Residential demand grew fifty-fold between 1906 and 1970. U.S. natural gas production peaked at about 22 trillion cubic feet in 1973, and has since drifted downwards in the range of 16-20 trillion cubic feet annually. In 1998, gas production totaled 18.71 trillion cubic feet.
Electricity Net Generation
Electric power arrived barely a hundred years ago, but it radically transformed and expanded energy use. Electricity’s broad and increasing usage from 1949 to 1998 is evident in many consumption indicators. For example, while the U.S. population grew by 82 percent, the amount of electricity sold by utilities grew 1,200 percent (Figure 9.7). Per-capita average consumption of electricity was six times higher in 1998 than in 1949. In 1998, the residential sector used the most (1.128 trillion kilowatt-hours), followed closely by the industrial sector (1.040 trillion kilowatt-hours), and then the commercial sector (0.969 trillion kilowatt-hours).
Coal has been and continues to be the source of most electricity, accounting for over half (1.808 trillion kilowatt-hours) of all electricity generated in 1998 (Figure 9.8). Hydroelectric power was an early source of U.S. electricity (accounting for almost a third of all utility generation in 1949) and remains a dependable contributor (about 9 percent of the total in 1998). Natural gas and petroleum grew steadily as sources of electricity in the late 1960s, but have since declined. Nuclear electricity began production in 1957 and increased steadily except for downturns in 1979 and 1980, following the accident at Three Mile Island, and again in 1993. Nuclear generation declined seven percent in 1997 but rebounded somewhat in 1998.
Nuclear Power Plant Operations
The number of U.S. operable nuclear reactor units peaked in 1990 at 112. As operable units have aged, some have become uneconomic to operate or have otherwise reached the end of their useful lives. At the end of 1998, 28 once-operable units had been shutdown permanently, leaving an inventory of 104. The Department of Energy projects that 51 percent of existing nuclear capacity will be retired by 2020, and does not expect any new plants to be built during the period.
U.S. Net Energy Imports by Source
Through the late 1950s, U.S. production and consumption of energy were nearly in balance. Over the following decade, however, consumption slightly outpaced domestic production and by the early 1970s a more significant gap had developed. Petroleum is by far the largest source of imported energy in the United States, accounting for 19.12 quadrillion Btu out of the net total of 23 quads of energy imports in 1998 (Figure 9.9). The 1998 net import level represents a 17-fold increase over the 1949 level.
U.S. Total Energy Consumption by Sector
In 1949, U.S. industry accounted for almost half of total energy consumption — 14.7 quads out of a national total of 32.0 quads, compared to 9.3 quads for combined residential and commercial and 8.0 quads for the transportation sector. Since then, all sectors have increased their consumption, but residential and commercial consumption has risen to be nearly equal to the industrial sector (Figure 9.10).
Per Capita Total Energy Consumption
The efficiency with which Americans use energy has improved over the years. One such measure is the amount of energy consumed to produce a (constant) dollar’s worth of gross domestic product (GDP). By that measure, efficiency improved by 42 percent between 1949 and 1998, as energy consumption per dollar of GDP fell from 21.6 thousand Btu to 12.5 thousand Btu (Figure 9.11). Nevertheless, a growing population and economy drove total energy use up. Between 1949 and 1998, the U.S. population expanded from 149 million people to 270 million people (an increase of 82 percent), total energy consumption grew from 32 quadrillion Btu to 94 quadrillion Btu (up 194 percent), and per capita energy consumption rose from 215 million Btu to 352 million Btu (up 62 percent) (Figure 9.12).
U.S. Renewable Energy Production
U.S. renewable energy production is now almost 10 percent of total U.S. energy production (Figure 9.13). About half of the U.S. renewable total in 1998 came from hydroelectric power generation. Biomass energy was second in 1998, accounting for about 43 percent of U.S. renewable energy production, followed by geothermal energy (3 percent), solar energy (about 1 percent) and wind energy (one-half percent).
Industrial sources and electric utilities account for about 90 percent of all renewable energy consumption.
U.S. Energy Intensity by Source
Energy intensity is another measure of energy efficiency. In the late 1970s and early 1980s, energy intensity in the residential and commercial sectors fell as a result of energy conservation improvements; since then, estimates of energy intensity in these two sectors have been about the same. Similarly, energy intensity fell during the 1977-84 period in the manufacturing sector, but has apparently stayed about the same since then.
Energy intensity for both passenger cars and trucks has declined steadily over the 1977-1998 period, but the decline has been less dramatic in the 1990s.
References
Davis, S.C., Transportation Energy Databook, Edition 20 (U.S. Department of Energy, Oak Ridge National Laboratory, Center for Transportation Analysis, Oak Ridge, TN, 2000). (http://www-cta.ornl.gov/data/tedb.htm)
U.S. Department of Energy, Energy Information Administration, Annual Energy Review 1998 (DOE, EIA,Washington, DC, 1999). (http://www.eia.doe.gov/emeu/aer/contents.html)
--, U.S. Coal Reserves: 1997 Update (DOE, EIA, Washington, DC, 1999). (http://www.eia.doe.gov/cneaf/coal/reserves/front-1.html)
--, U.S. Crude Oil, Natural Gas, and Natural Gas Liquids Reserves 1998 Annual Report (DOE, EIA, Washington, DC, 1999). (http://www.eia.doe.gov/oil_gas/natural_gas/data_publications/crude_oil_natural_gas_reserves/cr.html)
