Energy use in the United States

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The United States is the largest energy consumer in terms of total use, using 100 quadrillion BTU (105 exajoules, or 29000 TWh) in 2005, equivalent to an (average) consumption rate of 3.3 TW. The U.S. ranks seventh in energy consumption per-capita after Canada and a number of small countries.^[1][2] The majority of this energy is derived from fossil fuels: in 2005, it was estimated that 40% of the nation's energy came from petroleum, 23% from coal, and 23% from natural gas. The remaining 14% was supplied by nuclear power, hydroelectric dams, and miscellaneous renewable energy sources.^[3]

[edit] History

US energy consumption, by source, 1850-2000. Vertical axis is in quadrillion BTU

From its founding until the late 1800s, the United States was a largely agrarian country with abundant forests. During this period, energy consumption overwhelmingly focused on readily available firewood. Rapid industrialization of the economy, urbanization, and the growth of railroads led to increased use of coal, and by 1885 it had eclipsed wood as the nation's primary energy source. Coal remained dominant for the next 7 decades, but by 1950, it was surpassed in turn by both petroleum and natural gas. While coal consumption today is the highest it has ever been, it is now mostly used to generate electricity. Natural gas, which is cleaner-burning and more easily transportable, has replaced coal as the preferred source of heating in homes, businesses and industrial furnaces.

Petroleum began the 20th century as a minor resource used to manufacture lubricants and fuel for kerosene and oil lamps. One hundred years later it had become the preeminent energy source for the U.S. and the rest of the world. This rise closely paralleled the emergence of the automobile as a major force in American culture and the economy. While petroleum is also used as a source for plastics and other chemicals, and powers various industrial processes, today two-thirds of oil consumption in the U.S. is in the form of its derived transportation fuels.^[4]

[edit] Current consumption

U.S. Energy Flow - 2002. Note that the breakdown of useful and waste energy in each sector (yellow vs. grey) is estimated arbitrarily and is not based on data.

The U.S. Department of Energy tracks national energy consumption in four broad sectors: industrial, transportation, residential, and commercial. The industrial sector has long been the country's largest energy user, currently representing about 33% of the total. Next in importance is the transportation sector, followed by the residential and commercial sectors.

The breakdown of energy consumption by source is given here:

[edit] Regional variation

Average annual residential electricity usage by city, 2000-2005. Measured in Kilowatt hours per customer.^[10]

Household energy use varies significantly across the United States. An average home in the Pacific region (consisting of California, Oregon, and Washington) consumes 35% less energy than a home in the South Central region. Most of the regional differences can be explained by climate. The heavily populated coastal areas of the Pacific states experience generally mild winters and summers, reducing the need for both home heating and air conditioning. The warm, humid climates of the South Central and South Atlantic regions lead to higher electricity usage, while the cold winters experienced in the Northeast and North Central regions result in much higher consumption of natural gas and heating oil.

Another reason for regional differences is the variety of building codes and environmental regulations found at the local and state level. California has some of the strictest environmental laws and building codes in the country, which may contribute to the fact that its per-household energy consumption is lower than all other states except Hawaii.

Major U.S. cities also show significant variation in per capita energy consumption. In addition to differences in regional climates and variations in building code standards, factors affecting energy use in cities include population density and building design. Townhouses are more energy efficient than single-family homes because less heat, for example, is wasted per person. While New York City, Chicago, and San Francisco are all northern cities with broadly similar climate patterns, energy use varies by population density. New York City is the densest city, followed by San Francisco, and then Chicago.

[edit] Oil consumption

This article may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (October 2007)

America's current petroleum demand, which continues to rise steadily, poses ever growing environmental problems, and dependence on foreign petroleum. U.S. oil consumption is approximately 21 million barrels/day, yet production is only 6 million barrels per day (950,000 m³/d). Cost to import oil is approximately $200 billion dollars a year. While it costs the Arabian Peninsula just one U.S. dollar to extract a barrel of oil, the cost on the world market has varied up to $100/barrel in 2007 dollars. While U.S. oil usage increases by 2% per year, the economy has been growing at 3.3% per year. Over the past several decades, the petroleum cartel has self-imposed intentional cuts in oil production - either because they seek higher profits, or because of their protesting of American foreign policy. These production cuts have caused drops in the U.S. stock markets, but have sometimes been ameliorated by the United States releasing more of its reserves. The Strategic Petroleum Reserve currently holds about 640 million barrels (102,000,000 m³) of oil and is being filled to a level of 700 million barrels (110,000,000 m³). Should, for example, oil production be stopped entirely, or becomes depleted, the U.S. would have only 32 to 35 days of resources to fall back upon. From a national security standpoint, such a situation is untenable,^[who?] and calls for the immediate incubation of long term energy solutions prior to a 'peak oil' scenario which would force the economy to grinding halt. Although additional drilling in areas such as continental shelf, the Gulf of Mexico, off the U.S. West Coast, Alaska, and the Great Lakes may stave off the inevitability of the problem, it would be only a temporary solution, and carries the risk of further polluting our environment.

[edit] Electricity Production

Electricity production by source.      thermofosill      hydroelectric      nuclear      Other renewables

That United States has and continues to get most of its electrical production from conventional thermal power plants. Most of these are coal, however, the 1990s and 2000s have seen a disproportionate increase in natural gas and other kinds of gas powered plants.

From 1992 to 2005 some 270,000 MWe (Megawatt electric) of new gas-fired plant were built, but only 14,000 MWe of new nuclear and coal-fired capacity came on line, mostly coal, with 2,315 MWe of that being nuclear.^[11] Nuclear and coal are considerably capital intensive when compared to gas, and the great shift to gas plant construction is often attributed to deregulation and other political and economic factors.

As of 2007, there are a large number of new coal plants on order to keep up with fast increasing projected demand.

Hydroelectricity's contribution has been mostly constant throughout recent decades as has the contribution from new kinds of renewables including wind power and solar power, except for a sudden increase around 1990. Non-hydro renewable sources are also expected to increase in coming years.

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[edit] Energy consumption of computers in the USA

Visible or embedded (i. e. hidden) computers are found everywhere: in all sectors listed in the above chapter, as well as in all subsectors listed in the column entitled Major uses in the above tables. For the total of this cyberinfrastructure a study by Mark. P. Mills ^[13] of the Green Earth Society reported for the year 1999 an electricity consumption of 13% of the entire US electricity consumption. For the year 2020 this study predicted a consumption of 35 - 50% of all kWh used in the US. Numerous researchers questioned Mills' methodology and claimed that in numerous instances he was off by an order of magnitude. Berkeley Lab's Environmental Energy Technologies Division concluded that office and network equipment consume about three percent of the total U.S. electricity use. Although Mills' numbers were disputed as gross overestimates by researchers at Lawrence Berkeley Labs and elsewhere^[14][15], energy consumption of computers became an important political issue at least at the national level. In 2006 the US Senate started a study of the energy consumption of Server farms.

[edit] References

[edit] See also

Energy Portal

Sustainable development Portal

• The Climate Registry
• Efficient energy use
• Energy conservation
• Energy development
• Energy security
• Energy: world resources and consumption
• Peak oil

[edit] External links

• Energy Charts: Consumption, Oil Production & Imports
• Biomass Energy Data Book
• Buildings Energy Data Book
• Power Technologies Energy Data Book
• Transportation Energy Data Book