Energy

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 The following adapted from http://en.wikipedia.org/wiki/Energy_in_the_United_States as of January 2011

The US is the largest energy consumer in terms of total use, using 100 quadrillion BTUs (105 exajoules, or 29 PWh) in 2005. This is three times the consumption by the US in 1950. The U.S. ranks seventh in energy consumption per-capita after Canada and a number of small countries.

The vast 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. Nuclear power supplied 8.4% andrenewable energy supplied 7.3%, which was mainly from hydroelectric dams although other renewables are included such as wind power, geothermal and solar energy.  Energy consumption has increased at a faster rate than energy production over the last fifty years in the U.S.(when they were roughly equal). This difference is now largely met through imports.

According to the Energy Information Administration's statistics, the per-capita energy consumption in the US has been somewhat consistent from the 1970s to today. The average has been 335.9 million BTUs per person from 1980 to 2006. One explanation suggested for this is that the energy required to produce the increase in US consumption of manufactured equipment, cars, and other goods has been shifted to other countries producing and transporting those goods to the US with a corresponding shift of green house gases and pollution. In comparison, the world average has increased from 63.7 in 1980 to 72.4 million BTU's per person in 2006. On the other hand, US "off-shoring" of manufacturing is sometimes exaggerated: US domestic manufacturing has grown by 50% since 1980.

The development of renewable energy and energy efficiency marks "a new era of energy exploration" in the United States, according to President Barack Obama.

History

US energy consumption, by source, 1850-2000. Vertical axis is in quadrillion BTU
From its founding until the late 18th century, 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 ofcoal, 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. Although total energy use increased dramatically during this period, by approximately a factor of 50 between 1850 and 2000, energy use per capita increased only by a factor of 4.

At the beginning of the 20th century, petroleum was 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. Oil's unique qualities for transportation fuels in terms of energy content, cost of production, and speed of refueling have made it difficult to supplant with technological alternatives developed so far.

In June 2010, the American Energy Innovation Council,(which includes Bill Gates, Microsoft; Jeffrey R. Immelt, chief executive of General Electric; and John Doerr) has urged the government to more than triple spending on energy research and development, to $16 billion a year. Mr. Gates endorsed the administration’s goal of reducing greenhouse gas emissions by 80 percent by 2050, but said that was not possible with today’s technology or politicism. He said that the only way to find such disruptive new technology was to pour large sums of money at the problem. The group notes that the federal government spends less than $5 billion a year on energy research and development, not counting one-time stimulus projects. About $30 billion is spent annually on health research and more than $80 billion on military R.& D. They advocate a jump in spending on basic energy research.

Current consumption

U.S. Energy Flow - 2009. A quad is 1015 BTU, or 1.055 × 1018joules. Note that the breakdown of useful and waste energy in each sector (yellow vs. grey) may be misleading because much of the 'lost' energy consists of unavoidable losses arising from the Second Law of thermodynamics: heat engines cannot convert 100% of thermal energy into useful work, and must dump a fraction of waste heat into the environment.
USenergy2004.jpg

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.

Sector Summary
Sector Name Description Major uses
Industrial Facilities and equipment used for producing and processing goods. 22% chemical production
16% petroleum refining
14% metal smelting/refining
Transportation Vehicles which transport people/goods on ground, air or water. 61% gasoline fuel
21% diesel fuel
12% aviation
Residential Living quarters for private households. 32% space heating
13% water heating
12% lighting
11% air conditioning
8% refrigeration
5% electronics
5% wet-clean (mostly clothes dryers)
Commercial Service-providing facilities and equipment (businesses, government, other institutions). 25% lighting
13% heating
11% cooling
6% refrigeration
6% water heating
6% ventilation
6% electronics

The breakdown of energy consumption by source is given here:

Fuel type 2006 US consumption in PWh[12] 2006 World consumption in PWh[13]
Oil 11.71 50.33
Gas 6.50 31.65
Coal 6.60 37.38
Hydroelectric 0.84 8.71
Nuclear 2.41 8.14
Geothermal, wind,
solar, wood, waste
0.95 1.38
Total 29.26 138.41

U.S, Primary Energy Consumption by Source and Sector in 2008 is tabled as following:

Consumption Summary'[14]
Supply Sources Percent of Source Demand Sectors Percent of Sector
Petroleum
37.1%
71% Transportation
23% Industrial
5% Residential and Commercial
1% Electric Power
Transportation
27.8%
95% Petroleum
2% Natural Gas
3% Renewable Energy
Natural Gas
23.8%
3% Transportation
34% Industrial
34% Residential and Commercial
29% Electric Power
Industrial
20.6%
42% Petroleum
40% Natural Gas
9% Coal
10% Renewable Energy
Coal
22.5%
8% Industrial
<1% Residential and Commercial
91% Electric Power
Residential and Commercial
10.8%
16% Petroleum
76% Natural Gas
1% Coal
1% Renewable Energy
Renewable Energy
7.3%
11% Transportation
28% Industrial
10% Residential and Commercial
51% Electric Power
Electric Power
40.1%
1% Petroleum
17% Natural Gas
51% Coal
9% Renewable Energy
21% Nuclear Electric Power
Nuclear Electric Power
8.5%
100% Electric Power

Note: Sum of components may not equal 100 percent due to independent rounding.

Total Primary Consumption Historical Evolution in U.S until 2009.


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